<div><h4>Missense Mutation in Human CHD4 Causes Ventricular Noncompaction by Repressing ADAMTS1.</h4><i>Shi W, Scialdone AP, Emerson JI, Mei L, ... Cook JG, Conlon FL</i><br /><b>Background</b><br />Left ventricular noncompaction (LVNC) is a prevalent cardiomyopathy associated with excessive trabeculation and thin compact myocardium. Patients with LVNC are vulnerable to cardiac dysfunction and at high risk of sudden death. Although sporadic and inherited mutations in cardiac genes are implicated in LVNC, understanding of the mechanisms responsible for human LVNC is limited.<br /><b>Methods</b><br />We screened the complete exome sequence database of the Pediatrics Cardiac Genomics Consortium and identified a cohort with a de novo CHD4 (chromodomain helicase DNA-binding protein 4) proband, CHD4<sup>M202I</sup>, with congenital heart defects. We engineered a humanized mouse model of CHD4<sup>M202I</sup> (mouse CHD4<sup>M195I</sup>). Histological analysis, immunohistochemistry, flow cytometry, transmission electron microscopy, and echocardiography were used to analyze cardiac anatomy and function. Ex vivo culture, immunopurification coupled with mass spectrometry, transcriptional profiling, and chromatin immunoprecipitation were performed to deduce the mechanism of CHD4<sup>M195I</sup>-mediated ventricular wall defects.<br /><b>Results</b><br /><i>CHD4</i><sup><i>M195I/M195I</i></sup> mice developed biventricular hypertrabeculation and noncompaction and died at birth. Proliferation of cardiomyocytes was significantly increased in <i>CHD4</i><sup><i>M195I</i></sup> hearts, and the excessive trabeculation was associated with accumulation of ECM (extracellular matrix) proteins and a reduction of ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif 1), an ECM protease. We rescued the hyperproliferation and hypertrabeculation defects in <i>CHD4</i><sup><i>M195I</i></sup> hearts by administration of ADAMTS1. Mechanistically, the CHD4<sup>M195I</sup> protein showed augmented affinity to endocardial BRG1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4). This enhanced affinity resulted in the failure of derepression of <i>Adamts1</i> transcription such that ADAMTS1-mediated trabeculation termination was impaired.<br /><b>Conclusions</b><br />Our study reveals how a single mutation in the chromatin remodeler CHD4, in mice or humans, modulates ventricular chamber maturation and that cardiac defects associated with the missense mutation CHD4<sup>M195I</sup> can be attenuated by the administration of ADAMTS1.<br /><br /><br /><br /><small>Circ Res: 31 May 2023; epub ahead of print</small></div>

<div><h4>Spatial Multiplexed Protein Profiling of Cardiac Ischemia-Reperfusion Injury.</h4><i>Yao L, He F, Zhao Q, Li D, ... Zhou B, Wang L</i><br /><b>Background</b><br />Reperfusion therapy is critical to myocardial salvage in the event of a myocardial infarction but is complicated by ischemia-reperfusion injury (IRI). Limited understanding of the spatial organization of cardiac cells, which governs cellular interaction and function, has hindered the search for targeted interventions minimizing the deleterious effects of IRI.<br /><b>Methods</b><br />We used imaging mass cytometry to characterize the spatial distribution and dynamics of cell phenotypes and communities in the mouse left ventricle following IRI. Heart sections were collected from 12 cardiac segments (basal, mid-cavity, apical, and apex of the anterior, lateral, and inferior wall) and 8 time points (before ischemia [I-0H], and postreperfusion [R-0H, R-2H, R-6H, R-12H, R-1D, R-3D, R-7D]), and stained with 29 metal-isotope-tagged antibodies. Cell community analysis was performed on reconstructed images, and the most disease-relevant cell type and target protein were selected for intervention of IRI.<br /><b>Results</b><br />We obtained a total of 251 multiplexed images, and identified 197 063 single cells, which were grouped into 23 distinct cell communities based on the structure of cellular neighborhoods. The cellular architecture was heterogeneous throughout the ventricular wall and exhibited swift changes following IRI. Analysis of proteins with posttranslational modifications in single cells unveiled 13 posttranslational modification intensity clusters and highlighted increased H3K9me3 (tri-methylated lysine 9 of histone H3) as a key regulatory response in endothelial cells during the middle stage of IRI. Erasing H3K9 methylation, by silencing its methyltransferase <i>Suv39h1</i> or overexpressing its demethylase <i>Kdm4d</i> in isolated endothelial cells, attenuated cardiac dysfunction and pathological remodeling following IRI. in vitro, H3K9me3 binding significantly increased at endothelial cell function-related genes upon hypoxia, suppressing tube formation, which was rescued by inhibiting H3K9me3.<br /><b>Conclusions</b><br />We mapped the spatiotemporal heterogeneity of cellular phenotypes in the adult heart upon IRI, and uncovered H3K9me3 in endothelial cells as a potential therapeutic target for alleviating pathological remodeling of the heart following myocardial IRI.<br /><br /><br /><br /><small>Circ Res: 30 May 2023; epub ahead of print</small></div>

<div><h4>Distinct Roles of DRP1 in Conventional and Alternative Mitophagy in Obesity Cardiomyopathy.</h4><i>Tong M, Mukai R, Mareedu S, Zhai P, ... Babu GJ, Sadoshima J</i><br /><b>Rationale</b><br />Obesity induces cardiomyopathy characterized by hypertrophy and diastolic dysfunction. Whereas mitophagy mediated through an Atg7-dependent mechanism serves as an essential mechanism to maintain mitochondrial quality during the initial development of obesity cardiomyopathy, Rab9-dependent alternative mitophagy takes over the role during the chronic phase. Although it has been postulated that DRP1 (dynamin-related protein 1)-mediated mitochondrial fission and consequent separation of the damaged portions of mitochondria are essential for mitophagy, the involvement of DRP1 in mitophagy remains controversial.<br /><b>Objective</b><br />We investigated whether endogenous DRP1 is essential in mediating the 2 forms of mitophagy during high-fat diet (HFD)-induced obesity cardiomyopathy and, if so, what the underlying mechanisms are.<br /><b>Methods and results</b><br />Mice were fed either a normal diet or an HFD (60 kcal %fat). Mitophagy, evaluated with Mito-Keima, was increased after 3 weeks of HFD consumption. The induction of mitophagy by HFD consumption was completely abolished in tamoxifen-inducible cardiac-specific <i>Drp1</i>knockout (<i>Drp1</i> MCM) mouse hearts, in which both diastolic and systolic dysfunction were exacerbated. The increase in LC3-dependent general autophagy and colocalization between LC3 and mitochondrial proteins was abolished in <i>Drp1</i> MCM mice. Activation of alternative mitophagy was also completely abolished in <i>Drp1</i> MCM mice during the chronic phase of HFD consumption. DRP1 was phosphorylated at Ser616, localized at the mitochondria-associated membranes, and associated with Rab9 and Fis1 only during the chronic, but not acute, phase of HFD consumption.<br /><b>Conclusions</b><br />DRP1 is an essential factor in mitochondrial quality control during obesity cardiomyopathy that controls multiple forms of mitophagy. Although DRP1 regulates conventional mitophagy through a mitochondria-associated membrane-independent mechanism during the acute phase, it acts as a component of the mitophagy machinery at the mitochondria-associated membranes in alternative mitophagy during the chronic phase of HFD consumption.<br /><br /><br /><br /><small>Circ Res: 26 May 2023; epub ahead of print</small></div>

<div><h4>LTBP4 (Latent Transforming Growth Factor Beta Binding Protein 4) Protects Against Renal Fibrosis via Mitochondrial and Vascular Impacts.</h4><i>Su CT, See DHW, Huang YJ, Jao TM, ... Huang JW, Hung KY</i><br /><b>Background</b><br />As a part of natural disease progression, acute kidney injury (AKI) can develop into chronic kidney disease via renal fibrosis and inflammation. LTBP4 (latent transforming growth factor beta binding protein 4) regulates transforming growth factor beta, which plays a role in renal fibrosis pathogenesis. We previously investigated the role of LTBP4 in chronic kidney disease. Here, we examined the role of LTBP4 in AKI.<br /><b>Methods</b><br />LTBP4 expression was evaluated in human renal tissues, obtained from healthy individuals and patients with AKI, using immunohistochemistry. <i>LTBP4</i> was knocked down in both C57BL/6 mice and human renal proximal tubular cell line HK-2. AKI was induced in mice and HK-2 cells using ischemia-reperfusion injury and hypoxia, respectively. Mitochondrial division inhibitor 1, an inhibitor of DRP1 (dynamin-related protein 1), was used to reduce mitochondrial fragmentation. Gene and protein expression were then examined to assess inflammation and fibrosis. The results of bioenergetic studies for mitochondrial function, oxidative stress, and angiogenesis were assessed.<br /><b>Results</b><br />LTBP4 expression was upregulated in the renal tissues of patients with AKI. <i>Ltbp4</i>-knockdown mice showed increased renal tissue injury and mitochondrial fragmentation after ischemia-reperfusion injury, as well as increased inflammation, oxidative stress, and fibrosis, and decreased angiogenesis. in vitro studies using HK-2 cells revealed similar results. The energy profiles of Ltbp4-deficient mice and LTBP4-deficient HK-2 cells indicated decreased ATP production. LTBP4-deficient HK-2 cells exhibited decreased mitochondrial respiration and glycolysis. Human aortic endothelial cells and human umbilical vein endothelial cells exhibited decreased angiogenesis when treated with LTBP4-knockdown conditioned media. Mitochondrial division inhibitor 1 treatment ameliorated inflammation, oxidative stress, and fibrosis in mice and decreased inflammation and oxidative stress in HK-2 cells.<br /><b>Conclusions</b><br />Our study is the first to demonstrate that LTBP4 deficiency increases AKI severity, consequently leading to chronic kidney disease. Potential therapies focusing on LTBP4-associated angiogenesis and LTBP4-regulated DRP1-dependent mitochondrial division are relevant to renal injury.<br /><br /><br /><br /><small>Circ Res: 26 May 2023; epub ahead of print</small></div>

<div><h4>PDE10A Inactivation Prevents Doxorubicin-Induced Cardiotoxicity and Tumor Growth.</h4><i>Chen S, Chen J, Du W, Mickelsen DM, ... Kumar S, Yan C</i><br /><b>Background</b><br />Cyclic nucleotides play critical roles in cardiovascular biology and disease. PDE10A (phosphodiesterase 10A) is able to hydrolyze both cAMP and cGMP. PDE10A expression is induced in various human tumor cell lines, and PDE10A inhibition suppresses tumor cell growth. Chemotherapy drug such as doxorubicin (DOX) is widely used in chemotherapy. However, cardiotoxicity of DOX remains to be a serious clinical complication. In the current study, we aim to determine the role of PDE10A and the effect of PDE10A inhibition on cancer growth and cardiotoxicity induced by DOX.<br /><b>Methods</b><br />We used global PDE10A KO (knockout) mice and PDE10A inhibitor TP-10 to block PDE10A function. DOX-induced cardiotoxicity was evaluated in C57Bl/6J mice and nude mice with implanted ovarian cancer xenografts. Isolated adult mouse cardiomyocytes and a human ovarian cancer cell line were used for in vitro functional and mechanistic studies.<br /><b>Results</b><br />We found that PDE10A deficiency or inhibition alleviated DOX-induced myocardial atrophy, apoptosis, and dysfunction in C57Bl/6J mice. RNA sequencing study revealed a number of PDE10A-regulated signaling pathways involved in DOX-induced cardiotoxicity. PDE10A inhibition increased the death, decreased the proliferation, and potentiated the effect of DOX on various human cancer cells. Importantly, in nude mice with implanted ovarian cancer xenografts, PDE10A inhibition attenuated tumor growth while protecting DOX-induced cardiotoxicity. In isolated cardiomyocytes, PDE10A contributed to DOX-induced cardiomyocyte death via increasing Top2β (topoisomerase 2β) expression, mitochondrial dysfunction, and DNA damage by antagonizing cGMP/PKG (protein kinase G) signaling. PDE10A contributed to cardiomyocyte atrophy via potentiating FoxO3 (forkhead box O3) signaling via both cAMP/PKA- (protein kinase A) and cGMP/PKG-dependent signaling.<br /><b>Conclusions</b><br />Taken together, our study elucidates a novel role for PDE10A in cardiotoxicity induced by DOX and cancer growth. Given that PDE10A has been already proven to be a safe drug target, PDE10A inhibition may represent a novel therapeutic strategy in cancer therapy, with effects preventing DOX-induced cardiotoxicity and simultaneously antagonizing cancer growth.<br /><br /><br /><br /><small>Circ Res: 26 May 2023; epub ahead of print</small></div>

<div><h4>HDL Function and Atherosclerosis: Reactive Dicarbonyls as Promising Targets of Therapy.</h4><i>Linton MF, Yancey PG, Tao H, Davies SS</i><br /><AbstractText>Epidemiologic studies detected an inverse relationship between HDL (high-density lipoprotein) cholesterol (HDL-C) levels and atherosclerotic cardiovascular disease (ASCVD), identifying HDL-C as a major risk factor for ASCVD and suggesting atheroprotective functions of HDL. However, the role of HDL-C as a mediator of risk for ASCVD has been called into question by the failure of HDL-C-raising drugs to reduce cardiovascular events in clinical trials. Progress in understanding the heterogeneous nature of HDL particles in terms of their protein, lipid, and small RNA composition has contributed to the realization that HDL-C levels do not necessarily reflect HDL function. The most examined atheroprotective function of HDL is reverse cholesterol transport, whereby HDL removes cholesterol from plaque macrophage foam cells and delivers it to the liver for processing and excretion into bile. Indeed, in several studies, HDL has shown inverse associations between HDL cholesterol efflux capacity and ASCVD in humans. Inflammation plays a key role in the pathogenesis of atherosclerosis and vulnerable plaque formation, and a fundamental function of HDL is suppression of inflammatory signaling in macrophages and other cells. Oxidation is also a critical process to ASCVD in promoting atherogenic oxidative modifications of LDL (low-density lipoprotein) and cellular inflammation. HDL and its proteins including apoAI (apolipoprotein AI) and PON1 (paraoxonase 1) prevent cellular oxidative stress and LDL modifications. Importantly, HDL in humans with ASCVD is oxidatively modified rendering HDL dysfunctional and proinflammatory. Modification of HDL with reactive carbonyl species, such as malondialdehyde and isolevuglandins, dramatically impairs the antiatherogenic functions of HDL. Importantly, treatment of murine models of atherosclerosis with scavengers of reactive dicarbonyls improves HDL function and reduces systemic inflammation, atherosclerosis development, and features of plaque instability. Here, we discuss the HDL antiatherogenic functions in relation to oxidative modifications and the potential of reactive dicarbonyl scavengers as a therapeutic approach for ASCVD.</AbstractText><br /><br /><br /><br /><small>Circ Res: 26 May 2023; 132:1521-1545</small></div>

<div><h4>Cardiovascular Brain Circuits.</h4><i>Mohanta SK, Yin C, Weber C, Godinho-Silva C, ... Chang RB, Habenicht AJR</i><br /><AbstractText>The cardiovascular system is hardwired to the brain via multilayered afferent and efferent polysynaptic axonal connections. Two major anatomically and functionally distinct though closely interacting subcircuits within the cardiovascular system have recently been defined: The artery-brain circuit and the heart-brain circuit. However, how the nervous system impacts cardiovascular disease progression remains poorly understood. Here, we review recent findings on the anatomy, structures, and inner workings of the lesser-known artery-brain circuit and the better-established heart-brain circuit. We explore the evidence that signals from arteries or the heart form a systemic and finely tuned cardiovascular brain circuit: afferent inputs originating in the arterial tree or the heart are conveyed to distinct sensory neurons in the brain. There, primary integration centers act as hubs that receive and integrate artery-brain circuit-derived and heart-brain circuit-derived signals and process them together with axonal connections and humoral cues from distant brain regions. To conclude the cardiovascular brain circuit, integration centers transmit the constantly modified signals to efferent neurons which transfer them back to the cardiovascular system. Importantly, primary integration centers are wired to and receive information from secondary brain centers that control a wide variety of brain traits encoded in engrams including immune memory, stress-regulating hormone release, pain, reward, emotions, and even motivated types of behavior. Finally, we explore the important possibility that brain effector neurons in the cardiovascular brain circuit network connect efferent signals to other peripheral organs including the immune system, the gut, the liver, and adipose tissue. The enormous recent progress vis-à-vis the cardiovascular brain circuit allows us to propose a novel neurobiology-centered cardiovascular disease hypothesis that we term the neuroimmune cardiovascular circuit hypothesis.</AbstractText><br /><br /><br /><br /><small>Circ Res: 26 May 2023; 132:1546-1565</small></div>

<div><h4>Inflammasomes and Atherosclerosis: a Mixed Picture.</h4><i>Tall AR, Bornfeldt KE</i><br /><AbstractText>The CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcome Study) and colchicine trials suggest an important role of inflammasomes and their major product IL-1β (interleukin 1β) in human atherosclerotic cardiovascular disease. Moreover, studies in mouse models indicate a causal role of inflammasomes and IL-1β in atherosclerosis. However, recent studies have led to a more granular view of the role of inflammasomes in atherosclerosis. Studies in hyperlipidemic mouse models suggest that prominent activation of the NLRP3 inflammasome requires a second hit such as defective cholesterol efflux, defective DNA repair, clonal hematopoiesis or diabetes. Similarly in humans some mutations promoting clonal hematopoiesis increase coronary artery disease risk in part by promoting inflammasome activation. Recent studies in mice and humans point to a wider role of the AIM2 (absent in melanoma 2) inflammasome in promoting cardiovascular disease including in some forms of clonal hematopoiesis and diabetes. These developments suggest a precision medicine approach in which treatments targeting inflammasomes or IL-1β might be best employed in clinical settings involving increased inflammasome activation.</AbstractText><br /><br /><br /><br /><small>Circ Res: 26 May 2023; 132:1505-1520</small></div>

<div><h4>Platelets and SARS-CoV-2 During COVID-19: Immunity, Thrombosis, and Beyond.</h4><i>Sciaudone A, Corkrey H, Humphries F, Koupenova M</i><br /><AbstractText>COVID-19 is characterized by dysregulated thrombosis and coagulation that can increase mortality in patients. Platelets are fast responders to pathogen presence, alerting the surrounding immune cells and contributing to thrombosis and intravascular coagulation. The SARS-CoV-2 genome has been found in platelets from patients with COVID-19, and its coverage varies according to the method of detection, suggesting direct interaction of the virus with these cells. Antibodies against Spike and Nucleocapsid have confirmed this platelet-viral interaction. This review discusses the immune, prothrombotic, and procoagulant characteristics of platelets observed in patients with COVID-19. We outline the direct and indirect interaction of platelets with SARS-CoV-2, the contribution of the virus to programmed cell death pathway activation in platelets and the consequent extracellular vesicle release. We discuss platelet activation and immunothrombosis in patients with COVID-19, the effect of Spike on platelets, and possible activation of platelets by classical platelet activation triggers as well as contribution of platelets to complement activation. As COVID-19-mediated thrombosis and coagulation are still not well understood in vivo, we discuss available murine models and mouse adaptable strains.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1272-1289</small></div>

<div><h4>Cell-Specific Mechanisms in the Heart of COVID-19 Patients.</h4><i>Tsai EJ, Cˇiháková D, Tucker NR</i><br /><AbstractText>From the onset of the pandemic, evidence of cardiac involvement in acute COVID-19 abounded. Cardiac presentations ranged from arrhythmias to ischemia, myopericarditis/myocarditis, ventricular dysfunction to acute heart failure, and even cardiogenic shock. Elevated serum cardiac troponin levels were prevalent among hospitalized patients with COVID-19; the higher the magnitude of troponin elevation, the greater the COVID-19 illness severity and in-hospital death risk. Whether these consequences were due to direct SARS-CoV-2 infection of cardiac cells or secondary to inflammatory responses steered early cardiac autopsy studies. SARS-CoV-2 was reportedly detected in endothelial cells, cardiac myocytes, and within the extracellular space. However, findings were inconsistent and different methodologies had their limitations. Initial autopsy reports suggested that SARS-CoV-2 myocarditis was common, setting off studies to find and phenotype inflammatory infiltrates in the heart. Nonetheless, subsequent studies rarely detected myocarditis. Microthrombi, cardiomyocyte necrosis, and inflammatory infiltrates without cardiomyocyte damage were much more common. In vitro and ex vivo experimental platforms have assessed the cellular tropism of SARS-CoV-2 and elucidated mechanisms of viral entry into and replication within cardiac cells. Data point to pericytes as the primary target of SARS-CoV-2 in the heart. Infection of pericytes can account for the observed pericyte and endothelial cell death, innate immune response, and immunothrombosis commonly observed in COVID-19 hearts. These processes are bidirectional and synergistic, rendering a definitive order of events elusive. Single-cell/nucleus analyses of COVID-19 myocardial tissue and isolated cardiac cells have provided granular data about the cellular composition and cell type-specific transcriptomic signatures of COVID-19 and microthrombi-positive COVID-19 hearts. Still, much remains unknown and more in vivo studies are needed. This review seeks to provide an overview of the current understanding of COVID-19 cardiac pathophysiology. Cell type-specific mechanisms and the studies that provided such insights will be highlighted. Given the unprecedented pace of COVID-19 research, more mechanistic details are sure to emerge since the writing of this review. Importantly, our current knowledge offers significant clues about the cardiac pathophysiology of long COVID-19, the increased postrecovery risk of cardiac events, and thus, the future landscape of cardiovascular disease.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1290-1301</small></div>

<div><h4>Repurposing Drugs for the Treatment of COVID-19 and Its Cardiovascular Manifestations.</h4><i>Wang RS, Loscalzo J</i><br /><AbstractText>COVID-19 is an infectious disease caused by SARS-CoV-2 leading to the ongoing global pandemic. Infected patients developed a range of respiratory symptoms, including respiratory failure, as well as other extrapulmonary complications. Multiple comorbidities, including hypertension, diabetes, cardiovascular diseases, and chronic kidney diseases, are associated with the severity and increased mortality of COVID-19. SARS-CoV-2 infection also causes a range of cardiovascular complications, including myocarditis, myocardial injury, heart failure, arrhythmias, acute coronary syndrome, and venous thromboembolism. Although a variety of methods have been developed and many clinical trials have been launched for drug repositioning for COVID-19, treatments that consider cardiovascular manifestations and cardiovascular disease comorbidities specifically are limited. In this review, we summarize recent advances in drug repositioning for COVID-19, including experimental drug repositioning, high-throughput drug screening, omics data-based, and network medicine-based computational drug repositioning, with particular attention on those drug treatments that consider cardiovascular manifestations of COVID-19. We discuss prospective opportunities and potential methods for repurposing drugs to treat cardiovascular complications of COVID-19.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1374-1386</small></div>

<div><h4>COVID-19, Myocarditis and Pericarditis.</h4><i>Fairweather D, Beetler DJ, Di Florio DN, Musigk N, Heidecker B, Cooper LT</i><br /><AbstractText>Viral infections are a leading cause of myocarditis and pericarditis worldwide, conditions that frequently coexist. Myocarditis and pericarditis were some of the early comorbidities associated with SARS-CoV-2 infection and COVID-19. Many epidemiologic studies have been conducted since that time concluding that SARS-CoV-2 increased the incidence of myocarditis/pericarditis at least 15× over pre-COVID levels although the condition remains rare. The incidence of myocarditis pre-COVID was reported at 1 to 10 cases/100 000 individuals and with COVID ranging from 150 to 4000 cases/100 000 individuals. Before COVID-19, some vaccines were reported to cause myocarditis and pericarditis in rare cases, but the use of novel mRNA platforms led to a higher number of reported cases than with previous platforms providing new insight into potential pathogenic mechanisms. The incidence of COVID-19 vaccine-associated myocarditis/pericarditis covers a large range depending on the vaccine platform, age, and sex examined. Importantly, the findings highlight that myocarditis occurs predominantly in male patients aged 12 to 40 years regardless of whether the cause was due to a virus-like SARS-CoV-2 or associated with a vaccine-a demographic that has been reported before COVID-19. This review discusses findings from COVID-19 and COVID-19 vaccine-associated myocarditis and pericarditis considering the known symptoms, diagnosis, management, treatment, and pathogenesis of disease that has been gleaned from clinical research and animal models. Sex differences in the immune response to COVID-19 are discussed, and theories for how mRNA vaccines could lead to myocarditis/pericarditis are proposed. Additionally, gaps in our understanding that need further research are raised.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1302-1319</small></div>

<div><h4>Renin-Angiotensin System and Sex Differences in COVID-19: A Critical Assessment.</h4><i>Chappell MC</i><br /><AbstractText>The current epidemic of corona virus disease (COVID-19) has resulted in an immense health burden that became the third leading cause of death and potentially contributed to a decline in life expectancy in the United States. The severe acute respiratory syndrome-related coronavirus-2 binds to the surface-bound peptidase angiotensin-converting enzyme 2 (ACE2, EC 3.4.17.23) leading to tissue infection and viral replication. ACE2 is an important enzymatic component of the renin-angiotensin system (RAS) expressed in the lung and other organs. The peptidase regulates the levels of the peptide hormones Ang II and Ang-(1-7), which have distinct and opposing actions to one another, as well as other cardiovascular peptides. A potential consequence of severe acute respiratory syndrome-related coronavirus-2 infection is reduced ACE2 activity by internalization of the viral-ACE2 complex and subsequent activation of the RAS (higher ratio of Ang II:Ang-[1-7]) that may exacerbate the acute inflammatory events in COVID-19 patients and possibly contribute to the effects of long COVID-19. Moreover, COVID-19 patients present with an array of autoantibodies to various components of the RAS including the peptide Ang II, the enzyme ACE2, and the AT<sub>1</sub> AT<sub>2</sub> and Mas receptors. Greater disease severity is also evident in male COVID-19 patients, which may reflect underlying sex differences in the regulation of the 2 distinct functional arms of the RAS. The current review provides a critical evaluation of the evidence for an activated RAS in COVID-19 subjects and whether this system contributes to the greater severity of severe acute respiratory syndrome-related coronavirus-2 infection in males as compared with females.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1320-1337</small></div>

<div><h4>Multimodality Cardiac Imaging in COVID.</h4><i>Holby SN, Richardson TL, Laws JL, McLaren TA, ... Clark DE, Hughes SG</i><br /><AbstractText>Infection with SARS-CoV-2, the virus that causes COVID, is associated with numerous potential secondary complications. Global efforts have been dedicated to understanding the myriad potential cardiovascular sequelae which may occur during acute infection, convalescence, or recovery. Because patients often present with nonspecific symptoms and laboratory findings, cardiac imaging has emerged as an important tool for the discrimination of pulmonary and cardiovascular complications of this disease. The clinician investigating a potential COVID-related complication must account not only for the relative utility of various cardiac imaging modalities but also for the risk of infectious exposure to staff and other patients. Extraordinary clinical and scholarly efforts have brought the international medical community closer to a consensus on the appropriate indications for diagnostic cardiac imaging during this protracted pandemic. In this review, we summarize the existing literature and reference major societal guidelines to provide an overview of the indications and utility of echocardiography, nuclear imaging, cardiac computed tomography, and cardiac magnetic resonance imaging for the diagnosis of cardiovascular complications of COVID.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1387-1404</small></div>

<div><h4>Vaccination-Associated Myocarditis and Myocardial Injury.</h4><i>Altman NL, Berning AA, Mann SC, Quaife RA, ... Campbell TB, Bristow MR</i><br /><AbstractText>SARS-CoV-2 vaccine-associated myocarditis/myocardial injury should be evaluated in the contexts of COVID-19 infection, other types of viral myocarditis, and other vaccine-associated cardiac disorders. COVID-19 vaccine-associated myocardial injury can be caused by an inflammatory immune cell infiltrate, but other etiologies such as microvascular thrombosis are also possible. The clinical diagnosis is typically based on symptoms and cardiac magnetic resonance imaging. Endomyocardial biopsy is confirmatory for myocarditis, but may not show an inflammatory infiltrate because of rapid resolution or a non-inflammatory etiology. Myocarditis associated with SARS-COVID-19 vaccines occurs primarily with mRNA platform vaccines, which are also the most effective. In persons aged >16 or >12 years the myocarditis estimated crude incidences after the first 2 doses of BNT162b2 and mRNA-1273 are approximately 1.9 and 3.5 per 100 000 individuals, respectively. These rates equate to excess incidences above control populations of approximately 1.2 (BNT162b2) and 1.9 (mRNA-1273) per 100 000 persons, which are lower than the myocarditis rate for smallpox but higher than that for influenza vaccines. In the studies that have included mRNA vaccine and SARS-COVID-19 myocarditis measured by the same methodology, the incidence rate was increased by 3.5-fold over control in COVID-19 compared with 1.5-fold for BNT162b2 and 6.2-fold for mRNA-1273. However, mortality and major morbidity are less and recovery is faster with mRNA vaccine-associated myocarditis compared to COVID-19 infection. The reasons for this include vaccine-associated myocarditis having a higher incidence in young adults and adolescents, typically no involvement of other organs in vaccine-associated myocarditis, and based on comparisons to non-COVID viral myocarditis an inherently more benign clinical course.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1338-1357</small></div>

<div><h4>Microfluidic Organ-Chips and Stem Cell Models in the Fight Against COVID-19.</h4><i>Satta S, Rockwood SJ, Wang K, Wang S, ... Hsiai TK, Sharma A</i><br /><AbstractText>SARS-CoV-2, the virus underlying COVID-19, has now been recognized to cause multiorgan disease with a systemic effect on the host. To effectively combat SARS-CoV-2 and the subsequent development of COVID-19, it is critical to detect, monitor, and model viral pathogenesis. In this review, we discuss recent advancements in microfluidics, organ-on-a-chip, and human stem cell-derived models to study SARS-CoV-2 infection in the physiological organ microenvironment, together with their limitations. Microfluidic-based detection methods have greatly enhanced the rapidity, accessibility, and sensitivity of viral detection from patient samples. Engineered organ-on-a-chip models that recapitulate in vivo physiology have been developed for many organ systems to study viral pathology. Human stem cell-derived models have been utilized not only to model viral tropism and pathogenesis in a physiologically relevant context but also to screen for effective therapeutic compounds. The combination of all these platforms, along with future advancements, may aid to identify potential targets and develop novel strategies to counteract COVID-19 pathogenesis.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1405-1424</small></div>

<div><h4>A Post-Pandemic Enigma: The Cardiovascular Impact of Post-Acute Sequelae of SARS-CoV-2.</h4><i>Singh TK, Zidar DA, McCrae K, Highland KB, ... Cameron SJ, Chung MK</i><br /><AbstractText>COVID-19 has become the first modern-day pandemic of historic proportion, affecting >600 million individuals worldwide and causing >6.5 million deaths. While acute infection has had devastating consequences, postacute sequelae of SARS-CoV-2 infection appears to be a pandemic of its own, impacting up to one-third of survivors and often causing symptoms suggestive of cardiovascular phenomena. This review will highlight the suspected pathophysiology of postacute sequelae of SARS-CoV-2, its influence on the cardiovascular system, and potential treatment strategies.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1358-1373</small></div>

<div><h4>Interaction of COVID-19 With Common Cardiovascular Disorders.</h4><i>Boulos PK, Freeman SV, Henry TD, Mahmud E, Messenger JC</i><br /><AbstractText>The onset and widespread dissemination of the severe acute respiratory syndrome coronavirus-2 in late 2019 impacted the world in a way not seen since the 1918 H1N1 pandemic, colloquially known as the Spanish Flu. Much like the Spanish Flu, which was observed to disproportionately impact young adults, it became clear in the early days of the coronavirus disease 2019 (COVID-19) pandemic that certain groups appeared to be at higher risk for severe illness once infected. One such group that immediately came to the forefront and garnered international attention was patients with preexisting cardiovascular disease. Here, we examine the available literature describing the interaction of COVID-19 with a myriad of cardiovascular conditions and diseases, paying particular attention to patients diagnosed with arrythmias, heart failure, and coronary artery disease. We further discuss the association of acute COVID-19 with de novo cardiovascular disease, including myocardial infarction due to coronary thrombosis, myocarditis, and new onset arrhythmias. We will evaluate various biochemical theories to explain these findings, including possible mechanisms of direct myocardial injury caused by the severe acute respiratory syndrome coronavirus-2 virus at the cellular level. Finally, we will discuss the strategies employed by numerous groups and governing bodies within the cardiovascular disease community to address the unprecedented challenges posed to the care of our most vulnerable patients, including heart transplant recipients, end-stage heart failure patients, and patients suffering from acute coronary syndromes, during the early days and height of the COVID-19 pandemic.</AbstractText><br /><br /><br /><br /><small>Circ Res: 12 May 2023; 132:1259-1271</small></div>

<div><h4>Critical Role of the cGAS-STING Pathway in Doxorubicin-Induced Cardiotoxicity.</h4><i>Luo W, Zou X, Wang Y, Dong Z, ... Sun A, Ge J</i><br /><b>Background</b><br />Doxorubicin is an effective chemotherapy drug for treating various types of cancer. However, lethal cardiotoxicity severely limits its clinical use. Recent evidence has indicated that aberrant activation of the cytosolic DNA-sensing cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-STING (stimulator of interferon genes) pathway plays a critical role in cardiovascular destruction. Here, we investigate the involvement of this mechanism in doxorubicin-induced cardiotoxicity (DIC).<br /><b>Methods</b><br />Mice were treated with low-dose doxorubicin to induce chronic DIC. The role of the cGAS-STING pathway in DIC was evaluated in <i>cGAS</i>-deficiency (c<i>GAS</i><sup>-/-</sup>), <i>Sting</i> deficiency (<i>Sting</i><sup>-/-</sup>), and interferon regulatory factor 3 (<i>Irf3</i>)-deficiency (<i>Irf3</i><sup>-/-</sup>) mice. Endothelial cell (EC)-specific conditional <i>Sting</i> deficiency (<i>Sting</i><sup>flox/flox</sup>/Cdh5-Cre<sup>ERT</sup>) mice were used to assess the importance of this pathway in ECs during DIC. We also examined the direct effects of the cGAS-STING pathway on nicotinamide adenine dinucleotide (NAD) homeostasis in vitro and in vivo.<br /><b>Results</b><br />In the chronic DIC model, we observed significant activation of the cGAS-STING pathway in cardiac ECs. Global <i>cGAS</i>, <i>Sting,</i> and <i>Irf3</i> deficiency all markedly ameliorated DIC. EC-specific <i>Sting</i> deficiency significantly prevented DIC and endothelial dysfunction. Mechanistically, doxorubicin activated the cardiac EC cGAS-STING pathway and its target, IRF3, which directly induced CD38 expression. In cardiac ECs, the cGAS-STING pathway caused a reduction in NAD levels and subsequent mitochondrial dysfunction via the intracellular NAD glycohydrolase (NADase) activity of CD38. Furthermore, the cardiac EC cGAS-STING pathway also regulates NAD homeostasis and mitochondrial bioenergetics in cardiomyocytes through the ecto-NADase activity of CD38. We also demonstrated that pharmacological inhibition of TANK-binding kinase 1 or CD38 effectively ameliorated DIC without compromising the anticancer effects of doxorubicin.<br /><b>Conclusions</b><br />Our findings indicate a critical role of the cardiac EC cGAS-STING pathway in DIC. The cGAS-STING pathway may represent a novel therapeutic target for preventing DIC.<br /><br /><br /><br /><small>Circ Res: 08 May 2023; epub ahead of print</small></div>

<div><h4>Downregulation of FKBP5 Promotes Atrial Arrhythmogenesis.</h4><i>Wang X, Song J, Yuan Y, Li L, ... Dobrev D, Li N</i><br /><b>Background</b><br />Atrial fibrillation (AF), the most common arrhythmia, is associated with the downregulation of <i>FKBP5</i> (encoding FKBP5 [FK506 binding protein 5]). However, the function of FKBP5 in the heart remains unknown. Here, we elucidate the consequences of cardiomyocyte-restricted loss of FKBP5 on cardiac function and AF development and study the underlying mechanisms.<br /><b>Methods</b><br />Right atrial samples from patients with AF were used to assess the protein levels of FKBP5. A cardiomyocyte-specific FKBP5 knockdown mouse model was established by crossbreeding <i>Fkbp5</i><sup><i>flox/flox</i></sup> mice with <i>Myh6</i><sup><i>MerCreMer/+</i></sup> mice. Cardiac function and AF inducibility were assessed by echocardiography and programmed intracardiac stimulation. Histology, optical mapping, cellular electrophysiology, and biochemistry were employed to elucidate the proarrhythmic mechanisms due to loss of cardiomyocyte FKBP5.<br /><b>Results</b><br />FKBP5 protein levels were lower in the atrial lysates of patients with paroxysmal AF or long-lasting persistent chronic AF. Cardiomyocyte-specific knockdown mice exhibited increased AF inducibility and duration compared with control mice. Enhanced AF susceptibility in cardiomyocyte-specific knockdown mice was associated with the development of action potential alternans and spontaneous Ca<sup>2+</sup> waves, and increased protein levels and activity of the NCX1 (Na<sup>+</sup>/Ca<sup>2+</sup>-exchanger 1), mimicking the cellular phenotype of chronic AF patients. FKBP5-deficiency enhanced transcription of <i>Slc8a1</i> (encoding NCX1) via transcription factor hypoxia-inducible factor 1α. In vitro studies revealed that FKBP5 negatively modulated the protein levels of hypoxia-inducible factor 1α by competitively interacting with heat-shock protein 90. Injections of the heat-shock protein 90 inhibitor 17-AAG normalized protein levels of hypoxia-inducible factor 1α and NCX1 and reduced AF susceptibility in cardiomyocyte-specific knockdown mice. Furthermore, the atrial cardiomyocyte-selective knockdown of FKBP5 was sufficient to enhance AF arrhythmogenesis.<br /><b>Conclusions</b><br />This is the first study to demonstrate a role for the FKBP5-deficiency in atrial arrhythmogenesis and to establish FKBP5 as a negative regulator of hypoxia-inducible factor 1α in cardiomyocytes. Our results identify a potential molecular mechanism for the proarrhythmic NCX1 upregulation in chronic AF patients.<br /><br /><br /><br /><small>Circ Res: 08 May 2023; epub ahead of print</small></div>

<div><h4>Transcriptomic and Proteomic of Gastrocnemius Muscle in Peripheral Artery Disease.</h4><i>Ferrucci L, Candia J, Ubaida-Mohien C, Lyaskov A, ... Peterson CA, McDermott MM</i><br /><b>Background</b><br />Few effective therapies exist to improve lower extremity muscle pathology and mobility loss due to peripheral artery disease (PAD), in part because mechanisms associated with functional impairment remain unclear.<br /><b>Methods</b><br />To better understand mechanisms of muscle impairment in PAD, we performed in-depth transcriptomic and proteomic analyses on gastrocnemius muscle biopsies from 31 PAD participants (mean age, 69.9 years) and 29 age- and sex-matched non-PAD controls (mean age, 70.0 years) free of diabetes or limb-threatening ischemia.<br /><b>Results</b><br />Transcriptomic and proteomic analyses suggested activation of hypoxia-compensatory mechanisms in PAD muscle, including inflammation, fibrosis, apoptosis, angiogenesis, unfolded protein response, and nerve and muscle repair. Stoichiometric proportions of mitochondrial respiratory proteins were aberrant in PAD compared to non-PAD, suggesting that respiratory proteins not in complete functional units are not removed by mitophagy, likely contributing to abnormal mitochondrial activity. Supporting this hypothesis, greater mitochondrial respiratory protein abundance was significantly associated with greater complex II and complex IV respiratory activity in non-PAD but not in PAD. Rate-limiting glycolytic enzymes, such as hexokinase and pyruvate kinase, were less abundant in muscle of people with PAD compared with non-PAD participants, suggesting diminished glucose metabolism.<br /><b>Conclusions</b><br />In PAD muscle, hypoxia induces accumulation of mitochondria respiratory proteins, reduced activity of rate-limiting glycolytic enzymes, and an enhanced integrated stress response that modulates protein translation. These mechanisms may serve as targets for disease modification.<br /><br /><br /><br /><small>Circ Res: 08 May 2023; epub ahead of print</small></div>

<div><h4>Role of Dickkopf-3 in Blood Pressure Regulation in Mice and Hypertensive Rats.</h4><i>Busceti CL, Carrizzo A, Bianchi F, De Lucia M, ... Nicoletti F, Vecchione C</i><br /><b>Background</b><br />Dkk3 (Dickkopf-3) is a secreted glycoprotein known for its proapoptotic and angiogenic activity. The role of Dkk3 in cardiovascular homeostasis is largely unknown. Remarkably, the Dkk3 gene maps within a chromosome segment linked to the hypertensive phenotype in spontaneously hypertensive rats (SHR).<br /><b>Methods</b><br />We used Dkk3<sup>-/-</sup> mice or stroke-resistant (sr) and stroke-prone (sp) SHR to examine the role of Dkk3 in the central and peripheral regulation of blood pressure (BP). We used lentiviral expression vector to rescue Dkk3 in knockout mice or to induce Dkk3 overexpression or silencing in SHR.<br /><b>Results</b><br />Genetic deletion of Dkk3 in mice enhanced BP and impaired endothelium-dependent acetylcholine-induced relaxation of resistance arteries. These alterations were rescued by restoring Dkk3 expression either in the periphery or in the CNS. Dkk3 was required for the constitutive expression of VEGF (vascular endothelium growth factor), and the action of Dkk3 on BP and endothelium-dependent vasorelaxation was mediated by VEGF-stimulated phosphatidylinositol-3-kinase pathway, leading to eNOS (endothelial NO synthase) activation both in resistance arteries and the CNS. The regulatory function of Dkk3 on BP was confirmed in SHR stroke-resistant and SHR stroke-prone in which was blunted in both resistance arteries and brainstem. In SHR stroke-resistant, lentiviral expression vector-induced Dkk3 expression in the CNS largely reduced BP, whereas Dkk3 knock-down further enhanced BP. In SHR stroke-prone challenged with a hypersodic diet, lentiviral expression vector-induced Dkk3 expression in the CNS displayed a substantial antihypertensive effect and delayed the occurrence of stroke.<br /><b>Conclusions</b><br />These findings demonstrate that Dkk3 acts as peripheral and central regulator of BP by promoting VEGF expression and activating a VEGF/Akt/eNOS hypotensive axis.<br /><br /><br /><br /><small>Circ Res: 05 May 2023; epub ahead of print</small></div>

<div><h4>Mechanism of Tumor-Platelet Communications in Cancer.</h4><i>Dudiki T, Veleeparambil M, Zhevlakova I, Biswas S, ... Podrez EA, Byzova TV</i><br /><b>Background</b><br />Thrombosis is one of the main complications in cancer patients often leading to mortality. However, the mechanisms underlying platelet hyperactivation are poorly understood.<br /><b>Methods and results</b><br />Murine and human platelets were isolated and treated with small extracellular vesicles (sEVs) from various cancer cell lines. We demonstrate that platelets very effectively take up sEVs from aggressive prostate cancer cells. The process of uptake is fast, proceeds effectively in circulation in mice, and is mediated by the abundant sEV-membrane protein-CD63. The uptake of cancer-sEVs leads to the accumulation of cancer cell-specific RNA in platelets in vitro and in vivo. The human prostate cancer-sEV-specific RNA marker PCA3 is detected in platelets of ~70% of prostate cancer patients. This was markedly reduced after prostatectomy. In vitro studies showed that platelet uptake of cancer-sEVs induces strong platelet activation in a CD63-RPTPα (receptor-like protein tyrosine phosphatase alpha)-dependent manner. In contrast to physiological agonists ADP and thrombin, sEVs activate platelets via a noncanonical mechanism dependent upon active translation. Intravital studies demonstrated accelerated thrombosis both in murine tumor models and in mice that received intravenous injections of cancer-sEVs. The prothrombotic effects of sEVs were rescued by blocking CD63.<br /><b>Conclusions</b><br />Tumors communicate with platelets by means of sEVs, which deliver cancer markers and activate platelets in a CD63-dependent manner leading to thrombosis. This emphasizes the diagnostic and prognostic value of platelet-associated cancer markers and identifies new pathways for intervention.<br /><br /><br /><br /><small>Circ Res: 05 May 2023; epub ahead of print</small></div>

<div><h4>BIN1, Myotubularin, and Dynamin-2 Coordinate T-Tubule Growth in Cardiomyocytes.</h4><i>Perdreau-Dahl H, Lipsett DB, Frisk M, Kermani F, ... Morth JP, Louch WE</i><br /><b>Background</b><br />Transverse tubules (t-tubules) form gradually in the developing heart, critically enabling maturation of cardiomyocyte Ca<sup>2+</sup> homeostasis. The membrane bending and scaffolding protein BIN1 (amphiphysin-2) has been implicated in this process. However, it is unclear which of the various reported BIN1 isoforms are involved, and whether BIN1 function is regulated by its putative binding partners MTM1 (myotubularin), a phosphoinositide 3\'-phosphatase, and DNM2 (dynamin-2), a GTPase believed to mediate membrane fission.<br /><b>Methods</b><br />We investigated the roles of BIN1, MTM1, and DNM2 in t-tubule formation in developing mouse cardiomyocytes, and in gene-modified HL-1 and human-induced pluripotent stem cell-derived cardiomyocytes. T-tubules and proteins of interest were imaged by confocal and Airyscan microscopy, and expression patterns were examined by RT-qPCR and Western blotting. Ca<sup>2+</sup> release was recorded using Fluo-4.<br /><b>Results</b><br />We observed that in the postnatal mouse heart, BIN1 localizes along Z-lines from early developmental stages, consistent with roles in initial budding and scaffolding of t-tubules. T-tubule proliferation and organization were linked to a progressive and parallel increase in 4 detected BIN1 isoforms. All isoforms were observed to induce tubulation in cardiomyocytes but produced t-tubules with differing geometries. BIN1-induced tubulations contained the L-type Ca<sup>2+</sup> channel, were colocalized with caveolin-3 and the ryanodine receptor, and effectively triggered Ca<sup>2+</sup> release. BIN1 upregulation during development was paralleled by increasing expression of MTM1. Despite no direct binding between MTM1 and murine cardiac BIN1 isoforms, which lack exon 11, high MTM1 levels were necessary for BIN1-induced tubulation, indicating a central role of phosphoinositide homeostasis. In contrast, the developing heart exhibited declining levels of DNM2. Indeed, we observed that high levels of DNM2 are inhibitory for t-tubule formation, although this protein colocalizes with BIN1 along Z-lines, and binds all 4 isoforms.<br /><b>Conclusions</b><br />These findings indicate that BIN1, MTM1, and DNM2 have balanced and collaborative roles in controlling t-tubule growth in cardiomyocytes.<br /><br /><br /><br /><small>Circ Res: 04 May 2023; epub ahead of print</small></div>

<div><h4>A Critical Role for ERO1α in Arterial Thrombosis and Ischemic Stroke.</h4><i>Jha V, Xiong B, Kumari T, Brown G, ... Italiano JE, Cho J</i><br /><b>Background</b><br />Platelet adhesion and aggregation play a crucial role in arterial thrombosis and ischemic stroke. Here, we identify platelet ERO1α (endoplasmic reticulum oxidoreductase 1α) as a novel regulator of Ca<sup>2+</sup> signaling and a potential pharmacological target for treating thrombotic diseases.<br /><b>Methods</b><br />Intravital microscopy, animal disease models, and a wide range of cell biological studies were utilized to demonstrate the pathophysiological role of ERO1α in arteriolar and arterial thrombosis and to prove the importance of platelet ERO1α in platelet activation and aggregation. Mass spectrometry, electron microscopy, and biochemical studies were used to investigate the molecular mechanism. We used novel blocking antibodies and small-molecule inhibitors to study whether ERO1α can be targeted to attenuate thrombotic conditions.<br /><b>Results</b><br />Megakaryocyte-specific or global deletion of Ero1α in mice similarly reduced platelet thrombus formation in arteriolar and arterial thrombosis without affecting tail bleeding times and blood loss following vascular injury. We observed that platelet ERO1α localized exclusively in the dense tubular system and promoted Ca<sup>2+</sup> mobilization, platelet activation, and aggregation. Platelet ERO1α directly interacted with STIM1 (stromal interaction molecule 1) and SERCA2 (sarco/endoplasmic reticulum Ca<sup>2+</sup>-ATPase 2) and regulated their functions. Such interactions were impaired in mutant STIM1-Cys49/56Ser and mutant SERCA2-Cys875/887Ser. We found that ERO1α modified an allosteric Cys49-Cys56 disulfide bond in STIM1 and a Cys875-Cys887 disulfide bond in SERCA2, contributing to Ca<sup>2+</sup> store content and increasing cytosolic Ca<sup>2+</sup> levels during platelet activation. Inhibition of Ero1α with small-molecule inhibitors but not blocking antibodies attenuated arteriolar and arterial thrombosis and reduced infarct volume following focal brain ischemia in mice.<br /><b>Conclusions</b><br />Our results suggest that ERO1α acts as a thiol oxidase for Ca<sup>2+</sup> signaling molecules, STIM1 and SERCA2, and enhances cytosolic Ca<sup>2+</sup> levels, promoting platelet activation and aggregation. Our study provides evidence that ERO1α may be a potential target to reduce thrombotic events.<br /><br /><br /><br /><small>Circ Res: 03 May 2023; epub ahead of print</small></div>

<div><h4>Lessons of Vascular Specialization From Secondary Lymphoid Organ Lymphatic Endothelial Cells.</h4><i>Arroz-Madeira S, Bekkhus T, Ulvmar MH, Petrova TV</i><br /><AbstractText>Secondary lymphoid organs, such as lymph nodes, harbor highly specialized and compartmentalized niches. These niches are optimized to facilitate the encounter of naive lymphocytes with antigens and antigen-presenting cells, enabling optimal generation of adaptive immune responses. Lymphatic vessels of lymphoid organs are uniquely specialized to perform a staggering variety of tasks. These include antigen presentation, directing the trafficking of immune cells but also modulating immune cell activation and providing factors for their survival. Recent studies have provided insights into the molecular basis of such specialization, opening avenues for better understanding the mechanisms of immune-vascular interactions and their applications. Such knowledge is essential for designing better treatments for human diseases given the central role of the immune system in infection, aging, tissue regeneration and repair. In addition, principles established in studies of lymphoid organ lymphatic vessel functions and organization may be applied to guide our understanding of specialization of vascular beds in other organs.</AbstractText><br /><br /><br /><br /><small>Circ Res: 28 Apr 2023; 132:1203-1225</small></div>

<div><h4>Clinical Potential of Adrenomedullin Signaling in the Cardiovascular System.</h4><i>Bálint L, Nelson-Maney NP, Tian Y, Serafin SD, Caron KM</i><br /><AbstractText>Numerous clinical studies have revealed the utility of circulating AM (adrenomedullin) or MR-proAM (mid-regional proAM 45-92) as an effective prognostic and diagnostic biomarker for a variety of cardiovascular-related pathophysiologies. Thus, there is strong supporting evidence encouraging the exploration of the AM-CLR (calcitonin receptor-like receptor) signaling pathway as a therapeutic target. This is further bolstered because several drugs targeting the shared CGRP (calcitonin gene-related peptide)-CLR pathway are already Food and Drug Administration-approved and on the market for the treatment of migraine. In this review, we summarize the AM-CLR signaling pathway and its modulatory mechanisms and provide an overview of the current understanding of the physiological and pathological roles of AM-CLR signaling and the yet untapped potentials of AM as a biomarker or therapeutic target in cardiac and vascular diseases and provide an outlook on the recently emerged strategies that may provide further boost to the possible clinical applications of AM signaling.</AbstractText><br /><br /><br /><br /><small>Circ Res: 28 Apr 2023; 132:1185-1202</small></div>

<div><h4>Intestinal Lymphatic Dysfunction in Kidney Disease.</h4><i>Zhong J, Kirabo A, Yang HC, Fogo AB, Shelton EL, Kon V</i><br /><AbstractText>Kidney disease is associated with adverse consequences in many organs beyond the kidney, including the heart, lungs, brain, and intestines. The kidney-intestinal cross talk involves intestinal epithelial damage, dysbiosis, and generation of uremic toxins. Recent studies reveal that kidney injury expands the intestinal lymphatics, increases lymphatic flow, and alters the composition of mesenteric lymph. The intestinal lymphatics, like blood vessels, are a route for transporting potentially harmful substances generated by the intestines. The lymphatic architecture and actions are uniquely suited to take up and transport large macromolecules, functions that differentiate them from blood vessels, allowing them to play a distinct role in a variety of physiological and pathological processes. Here, we focus on the mechanisms by which kidney diseases result in deleterious changes in intestinal lymphatics and consider a novel paradigm of a vicious cycle of detrimental organ cross talk. This concept involves kidney injury-induced modulation of intestinal lymphatics that promotes production and distribution of harmful factors, which in turn contributes to disease progression in distant organ systems.</AbstractText><br /><br /><br /><br /><small>Circ Res: 28 Apr 2023; 132:1226-1245</small></div>

<div><h4>Electronic Nicotine Delivery Systems and Cardiovascular/Cardiometabolic Health.</h4><i>Mears MJ, Hookfin HL, Bandaru P, Vidal P, Stanford KI, Wold LE</i><br /><AbstractText>The use of electronic nicotine delivery systems, specifically electronic cigarettes (e-cig), has risen dramatically within the last few years; the demographic purchasing these devices is now predominantly adolescents that are not trying to quit the use of traditional combustible cigarettes, but rather are new users. The composition and appearance of these devices has changed since their first entry into the market in the late 2000s, but they remain composed of a battery and aerosol delivery system that is used to deliver breakdown products of propylene glycol/vegetable glycerin, flavorings, and potentially nicotine or other additives. Manufacturers have also adjusted the type of nicotine that is used within the liquid to make the inhalation more palatable for younger users, further affecting the number of youth who use these devices. Although the full spectrum of cardiovascular and cardiometabolic consequences of e-cig use is not fully appreciated, data is beginning to show that e-cigs can cause both short- and long-term issues on cardiac function, vascular integrity and cardiometabolic issues. This review will provide an overview of the cardiovascular, cardiometabolic, and vascular implications of the use of e-cigs, and the potential short- and long-term health effects. A robust understanding of these effects is important in order to inform policy makers on the dangers of e-cigs use.</AbstractText><br /><br /><br /><br /><small>Circ Res: 28 Apr 2023; 132:1168-1180</small></div>

<div><h4>The Lymphatic Vasculature in Cardiac Development and Ischemic Heart Disease.</h4><i>Liu X, Oliver G</i><br /><AbstractText>In recent years, the lymphatic system has received increasing attention due to the fast-growing number of findings about its diverse novel functional roles in health and disease. It is well documented that the lymphatic vasculature plays major roles in the maintenance of tissue-fluid balance, the immune response, and in lipid absorption. However, recent studies have identified an additional growing number of novel and sometimes unexpected functional roles of the lymphatic vasculature in normal and pathological conditions in different organs. Among those, cardiac lymphatics have been shown to play important roles in heart development, ischemic cardiac disease, and cardiac disorders. In this review, we will discuss some of those novel functional roles of cardiac lymphatics, as well as the therapeutic potential of targeting lymphatics for the treatment of cardiovascular diseases.</AbstractText><br /><br /><br /><br /><small>Circ Res: 28 Apr 2023; 132:1246-1253</small></div>

<div><h4>NETs-Induced Thrombosis Impacts on Cardiovascular and Chronic Kidney Disease.</h4><i>Thakur M, Junho CVC, Bernhard SM, Schindewolf M, Noels H, Döring Y</i><br /><AbstractText>Arterial and venous thrombosis constitute a major source of morbidity and mortality worldwide. Association between thrombotic complications and cardiovascular and other chronic inflammatory diseases are well described. Inflammation and subsequent initiation of thrombotic events, termed immunothrombosis, also receive growing attention but are still incompletely understood. Nevertheless, the clinical relevance of aberrant immunothrombosis, referred to as thromboinflammation, is evident by an increased risk of thrombosis and cardiovascular events in patients with inflammatory or infectious diseases. Proinflammatory mediators released from platelets, complement activation, and the formation of NETs (neutrophil extracellular traps) initiate and foster immunothrombosis. In this review, we highlight and discuss prominent and emerging interrelationships and functions between NETs and other mediators in immunothrombosis in cardiovascular disease. Also, with patients with chronic kidney disease suffering from increased cardiovascular and thrombotic risk, we summarize current knowledge on neutrophil phenotype, function, and NET formation in chronic kidney disease. In addition, we elaborate on therapeutic targeting of NETs-induced immunothrombosis. A better understanding of the functional relevance of antithrombotic mediators which do not increase bleeding risk may provide opportunities for successful therapeutic interventions to reduce thrombotic risk beyond current treatment options.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:933-949</small></div>

<div><h4>Enhanced Mitochondria-SR Tethering Triggers Adaptive Cardiac Muscle Remodeling.</h4><i>Nichtová Z, Fernandez-Sanz C, De La Fuente S, Yuan Y, ... Sheu SS, Csordás G</i><br /><b>Background</b><br />Cardiac contractile function requires high energy from mitochondria, and Ca2<sup>+</sup> from the sarcoplasmic reticulum (SR). Via local Ca2<sup>+</sup> transfer at close mitochondria-SR contacts, cardiac excitation feedforward regulates mitochondrial ATP production to match surges in demand (excitation-bioenergetics coupling). However, pathological stresses may cause mitochondrial Ca2<sup>+</sup> overload, excessive reactive oxygen species production and permeability transition, risking homeostatic collapse and myocyte loss. Excitation-bioenergetics coupling involves mitochondria-SR tethers but the role of tethering in cardiac physiology/pathology is debated. Endogenous tether proteins are multifunctional; therefore, nonselective targets to scrutinize interorganelle linkage. Here, we assessed the physiological/pathological relevance of selective chronic enhancement of cardiac mitochondria-SR tethering.<br /><b>Methods</b><br />We introduced to mice a cardiac muscle-specific engineered tether (linker) transgene with a fluorescent protein core and deployed 2D/3D electron microscopy, biochemical approaches, fluorescence imaging, in vivo and ex vivo cardiac performance monitoring and stress challenges to characterize the linker phenotype.<br /><b>Results</b><br />Expressed in the mature cardiomyocytes, the linker expanded and tightened individual mitochondria-junctional SR contacts; but also evoked a marked remodeling with large dense mitochondrial clusters that excluded dyads. Yet, excitation-bioenergetics coupling remained well-preserved, likely due to more longitudinal mitochondria-dyad contacts and nanotunnelling between mitochondria exposed to junctional SR and those sealed away from junctional SR. Remarkably, the linker decreased female vulnerability to acute massive β-adrenergic stress. It also reduced myocyte death and mitochondrial calcium-overload-associated myocardial impairment in ex vivo ischemia/reperfusion injury.<br /><b>Conclusions</b><br />We propose that mitochondria-SR/endoplasmic reticulum contacts operate at a structural optimum. Although acute changes in tethering may cause dysfunction, upon chronic enhancement of contacts from early life, adaptive remodeling of the organelles shifts the system to a new, stable structural optimum. This remodeling balances the individually enhanced mitochondrion-junctional SR crosstalk and excitation-bioenergetics coupling, by increasing the connected mitochondrial pool and, presumably, Ca2<sup>+</sup>/reactive oxygen species capacity, which then improves the resilience to stresses associated with dysregulated hyperactive Ca2<sup>+</sup> signaling.<br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; epub ahead of print</small></div>

<div><h4>Role of the Microbiome in Gut-Heart-Kidney Cross Talk.</h4><i>Glorieux G, Nigam SK, Vanholder R, Verbeke F</i><br /><AbstractText>Homeostasis is a prerequisite for health. When homeostasis becomes disrupted, dysfunction occurs. This is especially the case for the gut microbiota, which under normal conditions lives in symbiosis with the host. As there are as many microbial cells in and on our body as human cells, it is unlikely they would not contribute to health or disease. The gut bacterial metabolism generates numerous beneficial metabolites but also uremic toxins and their precursors, which are transported into the circulation. Barrier function in the intestine, the heart, and the kidneys regulates metabolite transport and concentration and plays a role in inter-organ and inter-organism communication via small molecules. This communication is analyzed from the perspective of the remote sensing and signaling theory, which emphasizes the role of a large network of multispecific, oligospecific, and monospecific transporters and enzymes in regulating small-molecule homeostasis. The theory provides a systems biology framework for understanding organ cross talk and microbe-host communication involving metabolites, signaling molecules, nutrients, antioxidants, and uremic toxins. This remote small-molecule communication is critical for maintenance of homeostasis along the gut-heart-kidney axis and for responding to homeostatic perturbations. Chronic kidney disease is characterized by gut dysbiosis and accumulation of toxic metabolites. This slowly impacts the body, affecting the cardiovascular system and contributing to the progression of kidney dysfunction, which in its turn influences the gut microbiota. Preserving gut homeostasis and barrier functions or restoring gut dysbiosis and dysfunction could be a minimally invasive way to improve patient outcomes and quality of life in many diseases, including cardiovascular and kidney disease.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:1064-1083</small></div>

<div><h4>Endothelial Cell Dysfunction and Increased Cardiovascular Risk in Patients With Chronic Kidney Disease.</h4><i>Baaten CCFMJ, Vondenhoff S, Noels H</i><br /><AbstractText>The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective endothelial cell functions are impaired due to the proinflammatory, prothrombotic and uremic environment caused by the decline in kidney function, adding to the increase in cardiovascular complications in this vulnerable patient population. In this review, we discuss endothelial cell functioning in healthy conditions and the contribution of endothelial cell dysfunction to cardiovascular disease. Further, we summarize the phenotypic changes of the endothelium in chronic kidney disease patients and the relation of endothelial cell dysfunction to cardiovascular risk in chronic kidney disease. We also review the mechanisms that underlie endothelial changes in chronic kidney disease and consider potential pharmacological interventions that can ameliorate endothelial health.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:970-992</small></div>

<div><h4>Hypertension as Cardiovascular Risk Factor in Chronic Kidney Disease.</h4><i>Burnier M, Damianaki A</i><br /><AbstractText>Hypertension is the leading modifiable cause of premature death and hence one of the global targets of World Health Organization for prevention. Hypertension also affects the great majority of patients with chronic kidney disease (CKD). Both hypertension and CKD are intrinsically related, as hypertension is a strong determinant of worse renal and cardiovascular outcomes and renal function decline aggravates hypertension. This bidirectional relationship is well documented by the high prevalence of hypertension across CKD stages and the dual benefits of effective antihypertensive treatments on renal and cardiovascular risk reduction. Achieving an optimal blood pressure (BP) target is mandatory and requires several pharmacological and lifestyle measures. However, it also requires a correct diagnosis based on reliable BP measurements (eg, 24-hour ambulatory BP monitoring, home BP), especially for populations like patients with CKD where reduced or reverse dipping patterns or masked and resistant hypertension are frequent and associated with a poor cardiovascular and renal prognosis. Even after achieving BP targets, which remain debated in CKD, the residual cardiovascular risk remains high. Current antihypertensive options have been enriched with novel agents that enable to lower the existing renal and cardiovascular risks, such as SGLT2 (sodium-glucose cotransporter-2) inhibitors and novel nonsteroidal mineralocorticoid receptor antagonists. Although their beneficial effects may be driven mostly from actions beyond BP control, recent evidence underline potential improvements on abnormal 24-hour BP phenotypes such as nondipping. Other promising novelties are still to come for the management of hypertension in CKD. In the present review, we shall discuss the existing evidence of hypertension as a cardiovascular risk factor in CKD, the importance of identifying hypertension phenotypes among patients with CKD, and the traditional and novel aspects of the management of hypertensives with CKD.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:1050-1063</small></div>

<div><h4>Accelerated Vascular Aging in Chronic Kidney Disease: The Potential for Novel Therapies.</h4><i>Hobson S, Arefin S, Witasp A, Hernandez L, ... Shiels PG, Stenvinkel P</i><br /><AbstractText>The pathophysiology of vascular disease is linked to accelerated biological aging and a combination of genetic, lifestyle, biological, and environmental risk factors. Within the scenario of uncontrolled artery wall aging processes, CKD (chronic kidney disease) stands out as a valid model for detailed structural, functional, and molecular studies of this process. The cardiorenal syndrome relates to the detrimental bidirectional interplay between the kidney and the cardiovascular system. In addition to established risk factors, this group of patients is subjected to a plethora of other emerging vascular risk factors, such as inflammation, oxidative stress, mitochondrial dysfunction, vitamin K deficiency, cellular senescence, somatic mutations, epigenetic modifications, and increased apoptosis. A better understanding of the molecular mechanisms through which the uremic milieu triggers and maintains early vascular aging processes, has provided important new clues on inflammatory pathways and emerging risk factors alike, and to the altered behavior of cells in the arterial wall. Advances in the understanding of the biology of uremic early vascular aging opens avenues to novel pharmacological and nutritional therapeutic interventions. Such strategies hold promise to improve future prevention and treatment of early vascular aging not only in CKD but also in the elderly general population.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:950-969</small></div>

<div><h4>Fibrosis in Pathology of Heart and Kidney: From Deep RNA-Sequencing to Novel Molecular Targets.</h4><i>Schreibing F, Anslinger TM, Kramann R</i><br /><AbstractText>Diseases of the heart and the kidney, including heart failure and chronic kidney disease, can dramatically impair life expectancy and the quality of life of patients. The heart and kidney form a functional axis; therefore, functional impairment of 1 organ will inevitably affect the function of the other. Fibrosis represents the common final pathway of diseases of both organs, regardless of the disease entity. Thus, inhibition of fibrosis represents a promising therapeutic approach to treat diseases of both organs and to resolve functional impairment. However, despite the growing knowledge in this field, the exact pathomechanisms that drive fibrosis remain elusive. RNA-sequencing approaches, particularly single-cell RNA-sequencing, have revolutionized the investigation of pathomechanisms at a molecular level and facilitated the discovery of disease-associated cell types and mechanisms. In this review, we give a brief overview over the evolution of RNA-sequencing techniques, summarize most recent insights into the pathogenesis of heart and kidney fibrosis, and discuss how transcriptomic data can be used, to identify new drug targets and to develop novel therapeutic strategies.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:1013-1033</small></div>

<div><h4>Cardiovascular Calcification Heterogeneity in Chronic Kidney Disease.</h4><i>Hutcheson JD, Goettsch C</i><br /><AbstractText>Patients with chronic kidney disease (CKD) exhibit tremendously elevated risk for cardiovascular disease, particularly ischemic heart disease, due to premature vascular and cardiac aging and accelerated ectopic calcification. The presence of cardiovascular calcification associates with increased risk in patients with CKD. Disturbed mineral homeostasis and diverse comorbidities in these patients drive increased systemic cardiovascular calcification in different manifestations with diverse clinical consequences, like plaque instability, vessel stiffening, and aortic stenosis. This review outlines the heterogeneity in calcification patterning, including mineral type and location and potential implications on clinical outcomes. The advent of therapeutics currently in clinical trials may reduce CKD-associated morbidity. Development of therapeutics for cardiovascular calcification begins with the premise that less mineral is better. While restoring diseased tissues to a noncalcified homeostasis remains the ultimate goal, in some cases, calcific mineral may play a protective role, such as in atherosclerotic plaques. Therefore, developing treatments for ectopic calcification may require a nuanced approach that considers individual patient risk factors. Here, we discuss the most common cardiac and vascular calcification pathologies observed in CKD, how mineral in these tissues affects function, and the potential outcomes and considerations for therapeutic strategies that seek to disrupt the nucleation and growth of mineral. Finally, we discuss future patient-specific considerations for treating cardiac and vascular calcification in patients with CKD-a population in need of anticalcification therapies.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:993-1012</small></div>

<div><h4>Cardiac Metabolism in Heart Failure and Implications for Uremic Cardiomyopathy.</h4><i>Nguyen TD, Schulze PC</i><br /><AbstractText>Chronic kidney disease is associated with an increased risk for the development and progression of cardiovascular disorders including hypertension, dyslipidemia, and coronary artery disease. Chronic kidney disease may also affect the myocardium through complex systemic changes, resulting in structural remodeling such as hypertrophy and fibrosis, as well as impairments in both diastolic and systolic function. These cardiac changes in the setting of chronic kidney disease define a specific cardiomyopathic phenotype known as uremic cardiomyopathy. Cardiac function is tightly linked to its metabolism, and research over the past 3 decades has revealed significant metabolic remodeling in the myocardium during the development of heart failure. Because the concept of uremic cardiomyopathy has only been recognized in recent years, there are limited data on metabolism in the uremic heart. Nonetheless, recent findings suggest overlapping mechanisms with heart failure. This work reviews key features of metabolic remodeling in the failing heart in the general population and extends this to patients with chronic kidney disease. The knowledge of similarities and differences in cardiac metabolism between heart failure and uremic cardiomyopathy may help identify new targets for mechanistic and therapeutic research on uremic cardiomyopathy.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:1034-1049</small></div>

<div><h4>Use of Computation Ecosystems to Analyze the Kidney-Heart Crosstalk.</h4><i>Wu Z, Lohmöller J, Kuhl C, Wehrle K, Jankowski J</i><br /><AbstractText>The identification of mediators for physiologic processes, correlation of molecular processes, or even pathophysiological processes within a single organ such as the kidney or heart has been extensively studied to answer specific research questions using organ-centered approaches in the past 50 years. However, it has become evident that these approaches do not adequately complement each other and display a distorted single-disease progression, lacking holistic multilevel/multidimensional correlations. Holistic approaches have become increasingly significant in understanding and uncovering high dimensional interactions and molecular overlaps between different organ systems in the pathophysiology of multimorbid and systemic diseases like cardiorenal syndrome because of pathological heart-kidney crosstalk. Holistic approaches to unraveling multimorbid diseases are based on the integration, merging, and correlation of extensive, heterogeneous, and multidimensional data from different data sources, both -omics and nonomics databases. These approaches aimed at generating viable and translatable disease models using mathematical, statistical, and computational tools, thereby creating first computational ecosystems. As part of these computational ecosystems, systems medicine solutions focus on the analysis of -omics data in single-organ diseases. However, the data-scientific requirements to address the complexity of multimodality and multimorbidity reach far beyond what is currently available and require multiphased and cross-sectional approaches. These approaches break down complexity into small and comprehensible challenges. Such holistic computational ecosystems encompass data, methods, processes, and interdisciplinary knowledge to manage the complexity of multiorgan crosstalk. Therefore, this review summarizes the current knowledge of kidney-heart crosstalk, along with methods and opportunities that arise from the novel application of computational ecosystems providing a holistic analysis on the example of kidney-heart crosstalk.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:1084-1100</small></div>

<div><h4>Innate Immunity System in Patients With Cardiovascular and Kidney Disease.</h4><i>Zoccali C, Mallamaci F</i><br /><AbstractText>With a global burden of 844 million, chronic kidney disease (CKD) is now considered a public health priority. Cardiovascular risk is pervasive in this population, and low-grade systemic inflammation is an established driver of adverse cardiovascular outcomes in these patients. Accelerated cellular senescence, gut microbiota-dependent immune activation, posttranslational lipoprotein modifications, neuroimmune interactions, osmotic and nonosmotic sodium accumulation, acute kidney injury, and precipitation of crystals in the kidney and the vascular system all concur in determining the unique severity of inflammation in CKD. Cohort studies documented a strong link between various biomarkers of inflammation and the risk of progression to kidney failure and cardiovascular events in patients with CKD. Interventions targeting diverse steps of the innate immune response may reduce the risk of cardiovascular and kidney disease. Among these, inhibition of IL-1β (interleukin-1 beta) signaling by canakinumab reduced the risk for cardiovascular events in patients with coronary heart disease, and this protection was equally strong in patients with and without CKD. Several old (colchicine) and new drugs targeting the innate immune system, like the IL-6 (interleukin 6) antagonist ziltivekimab, are being tested in large randomized clinical trials to thoroughly test the hypothesis that mitigating inflammation may translate into better cardiovascular and kidney outcomes in patients with CKD.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:915-932</small></div>

<div><h4>The Cardio-Kidney Patient: Epidemiology, Clinical Characteristics and Therapy.</h4><i>Schuett K, Marx N, Lehrke M</i><br /><AbstractText>Patients with chronic kidney disease (CKD) are at high risk to develop cardiovascular disease with its manifestations coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. In addition, the presence of CKD has a major impact on the prognosis of patients with cardiovascular disease, leading to an increased morbidity and mortality if both comorbidities are present. Therapeutic options including medical therapy and interventional treatment are often limited in patients with advanced CKD, and in most cardiovascular outcome trials, patients with advanced CKD have been excluded. Thus, in many patients, treatment strategies for cardiovascular disease need to be extrapolated from trials conducted in patients without CKD. The current article summarizes the epidemiology, clinical presentation, and treatment options for the most prevalent manifestations of cardiovascular disease in CKD and discusses the currently available treatment options to reduce morbidity and mortality in this high-risk population.</AbstractText><br /><br /><br /><br /><small>Circ Res: 14 Apr 2023; 132:902-914</small></div>

<div><h4>Targeting Wnt-ß-Catenin-FOSL Signaling Ameliorates Right Ventricular Remodeling.</h4><i>Nayakanti SR, Friedrich A, Sarode P, Jafari L, ... Schermuly RT, Pullamsett SS</i><br /><b>Background</b><br />The ability of the right ventricle (RV) to adapt to an increased pressure afterload determines survival in patients with pulmonary arterial hypertension. At present, there are no specific treatments available to prevent RV failure, except for heart/lung transplantation. The wingless/int-1 (Wnt) signaling pathway plays an important role in the development of the RV and may also be implicated in adult cardiac remodeling.<br /><b>Methods</b><br />Molecular, biochemical, and pharmacological approaches were used both in vitro and in vivo to investigate the role of Wnt signaling in RV remodeling.<br /><b>Results</b><br />Wnt/β-catenin signaling molecules are upregulated in RV of patients with pulmonary arterial hypertension and animal models of RV overload (pulmonary artery banding-induced and monocrotaline rat models). Activation of Wnt/β-catenin signaling leads to RV remodeling via transcriptional activation of FOSL1 and FOSL2 (FOS like 1/2, AP-1 [activator protein 1] transcription factor subunit). Immunohistochemical analysis of pulmonary artery banding -exposed BAT-Gal reporter mice RVs exhibited an increase in β-catenin expression compared with their respective controls. Genetic inhibition of β-catenin, FOSL1/2, or WNT3A stimulation of RV fibroblasts significantly reduced collagen synthesis and other remodeling genes. Importantly, pharmacological inhibition of Wnt signaling using LGK-974 attenuated fibrosis and cardiac hypertrophy leading to improvement in RV function in both, pulmonary artery banding - and monocrotaline-induced RV overload.<br /><b>Conclusions</b><br />Wnt- β-Catenin-FOSL signaling is centrally involved in the hypertrophic RV response to increased afterload, offering novel targets for therapeutic interference with RV failure in pulmonary hypertension.<br /><br /><br /><br /><small>Circ Res: 12 Apr 2023; epub ahead of print</small></div>

<div><h4>Mechano-Redox Control of Macrophage-1 Antigen De-Adhesion From ICAM-1 (Intercellular Adhesion Molecule 1) by Protein Disulfide Isomerase Promotes Directional Movement Under Flow.</h4><i>Dupuy A, Aponte Santamaría C, Yeheskel A, Hortle E, ... Passam FH, Chiu J</i><br /><b>Background</b><br />Neutrophil migration is critical to the initiation and resolution of inflammation. Macrophage-1 antigen (Mac-1; CD11b/CD18, αMβ2) is a leukocyte integrin essential for firm adhesion to endothelial ICAM-1 (intercellular adhesion molecule 1) and migration of neutrophils in the shear forces of the circulation. PDI (protein disulfide isomerase) has been reported to influence neutrophil adhesion and migration. We aimed to elucidate the molecular mechanism of PDI control of Mac-1 affinity for ICAM-1 during neutrophil migration under fluid shear.<br /><b>Methods</b><br />Neutrophils isolated from whole blood were perfused over microfluidic chips coated with ICAM-1. Colocalization of Mac-1 and PDI on neutrophils was visualized by fluorescently labeled antibodies and confocal microscopy. The redox state of Mac-1 disulfide bonds was mapped by differential cysteine alkylation and mass spectrometry. Wild-type or disulfide mutant Mac-1 was expressed recombinantly in Baby Hamster Kidney cells to measure ligand affinity. Mac-1 conformations were measured by conformation-specific antibodies and molecular dynamics simulations. Neutrophils crawling on immobilized ICAM-1 were measured in presence of oxidized or reduced PDI, and the effect of PDI inhibition using isoquercetin on neutrophil crawling on inflamed endothelial cells was examined. Migration indices in the X- and Y-direction were determined and the crawling speed was calculated.<br /><b>Results</b><br />PDI colocalized with high-affinity Mac-1 at the trailing edge of stimulated neutrophils when crawling on ICAM-1 under fluid shear. PDI cleaved 2 allosteric disulfide bonds, C169-C176 and C224-C264, in the βI domain of the β2 subunit, and cleavage of the C224-C264 disulfide bond selectively controls Mac-1 disengagement from ICAM-1 under fluid shear. Molecular dynamics simulations and conformation-specific antibodies reveal that cleavage of the C224-C264 bond induces conformational change and mechanical stress in the βI domain. This allosterically alters the exposure of an αI domain epitope associated with a shift of Mac-1 to a lower-affinity state. These molecular events promote neutrophil motility in the direction of flow at high shear stress. Inhibition of PDI by isoquercetin reduces neutrophil migration in the direction of flow on endothelial cells during inflammation.<br /><b>Conclusions</b><br />Shear-dependent PDI cleavage of the neutrophil Mac-1 C224-C264 disulfide bond triggers Mac-1 de-adherence from ICAM-1 at the trailing edge of the cell and enables directional movement of neutrophils during inflammation.<br /><br /><br /><br /><small>Circ Res: 06 Apr 2023; epub ahead of print</small></div>

<div><h4>FHL5 Controls Vascular Disease-Associated Gene Programs in Smooth Muscle Cells.</h4><i>Wong D, Auguste G, Lino Cardenas CL, Turner AW, ... Malhotra R, Miller CL</i><br /><b>Background</b><br />Genome-wide association studies (GWAS) have identified hundreds of loci associated with common vascular diseases, such as coronary artery disease, myocardial infarction, and hypertension. However, the lack of mechanistic insights for many GWAS loci limits their translation into the clinic. Among these loci with unknown functions is <i>UFL1</i>-four-and-a-half LIM domain 5 (<i>FHL5</i>; chr6q16.1), which reached genome-wide significance in a recent coronary artery disease/ myocardial infarction GWAS meta-analysis. <i>UFL1-FHL5</i> is also associated with several vascular diseases, consistent with the widespread pleiotropy observed for GWAS loci.<br /><b>Methods</b><br />We apply a multimodal approach leveraging statistical fine-mapping, epigenomic profiling, and ex vivo analysis of human coronary artery tissues to implicate <i>FHL5</i> as the top candidate causal gene. We unravel the molecular mechanisms of the cross-phenotype genetic associations through in vitro functional analyses and epigenomic profiling experiments in coronary artery smooth muscle cells.<br /><b>Results</b><br />We prioritized <i>FHL5</i> as the top candidate causal gene at the <i>UFL1-FHL5</i> locus through expression quantitative trait locus colocalization methods. <i>FHL5</i> gene expression was enriched in the smooth muscle cells and pericyte population in human artery tissues with coexpression network analyses supporting a functional role in regulating smooth muscle cell contraction. Unexpectedly, under procalcifying conditions, FHL5 overexpression promoted vascular calcification and dysregulated processes related to extracellular matrix organization and calcium handling. Lastly, by mapping FHL5 binding sites and inferring FHL5 target gene function using artery tissue gene regulatory network analyses, we highlight regulatory interactions between FHL5 and downstream coronary artery disease/myocardial infarction loci, such as <i>FOXL1</i> and <i>FN1</i> that have roles in vascular remodeling.<br /><b>Conclusions</b><br />Taken together, these studies provide mechanistic insights into the pleiotropic genetic associations of <i>UFL1-FHL5.</i> We show that FHL5 mediates vascular disease risk through transcriptional regulation of downstream vascular remodeling gene programs. These transacting mechanisms may explain a portion of the heritable risk for complex vascular diseases.<br /><br /><br /><br /><small>Circ Res: 05 Apr 2023; epub ahead of print</small></div>

<div><h4>IL-37 Attenuates Platelet Activation and Thrombosis Through IL-1R8 Pathway.</h4><i>Chen Y, Hong J, Zhong H, Zhao Y, ... Liu J, Gao W</i><br /><b>Background</b><br />IL (interleukin)-37, a natural suppressor of innate inflammatory and immune responses, is increased in patients with myocardial infarction. Platelets play an important role in the progress of myocardial infarction, but the direct effects of IL-37 on platelet activation and thrombosis, as well as the underlying mechanisms, still remain unclear.<br /><b>Methods</b><br />We evaluated the direct effects of IL-37 on agonists-induced platelet activation and thrombus formation, as well as revealed the underlying mechanisms using platelet-specific IL-1R8 (IL-1 receptor 8)-deficient mice. Using myocardial infarct model, we explored the effects of IL-37 on microvascular obstruction and myocardial injury.<br /><b>Results</b><br />IL-37 directly inhibited agonists-induced platelet aggregation, dense granule ATP release, P-selectin exposure, integrin αIIbβ3 activation, platelet spreading, and clot retraction. IL-37 inhibited thrombus formation in vivo in a FeCl<sub>3</sub>-injured mesenteric arteriole thrombosis mouse model and ex vivo in a microfluidic whole-blood perfusion assay. Mechanistic studies using platelet-specific IL-1R8-deficient mice revealed that IL-37 bound to platelet IL-1R8 and IL-18Rα, and IL-1R8 deficiency impaired the inhibitory effects of IL-37 on platelet activation. Using PTEN (phosphatase and tensin homolog)-specific inhibitor and PTEN-deficient platelets, we found that IL-37 combined with IL-1R8 to enhance PTEN activity, inhibit Akt, mitogen-activated protein kinases, and spleen tyrosine kinase pathways, as well as decrease the generation of reactive oxygen species to regulate platelet activation. Exogenous IL-37 injection suppressed microvascular thrombosis to protect against myocardial injury in wild-type mice but not in platelet-specific IL-1R8-deficient mice after permanent ligation of the left anterior descending coronary. Finally, a negative correlation between plasma IL-37 concentration and platelet aggregation was observed in patients with myocardial infarction.<br /><b>Conclusions</b><br />IL-37 directly attenuated platelet activation, thrombus formation, and myocardial injury via IL-1R8 receptor. Accumulated IL-37 in plasma inhibited platelet activation to ameliorate atherothrombosis and infarction expansion, and thus may have therapeutic advantages as potential antiplatelet drugs.<br /><br /><br /><br /><small>Circ Res: 31 Mar 2023; epub ahead of print</small></div>

<div><h4>Ketones and the Heart: Metabolic Principles and Therapeutic Implications.</h4><i>Matsuura TR, Puchalska P, Crawford PA, Kelly DP</i><br /><AbstractText>The ketone bodies beta-hydroxybutyrate and acetoacetate are hepatically produced metabolites catabolized in extrahepatic organs. Ketone bodies are a critical cardiac fuel and have diverse roles in the regulation of cellular processes such as metabolism, inflammation, and cellular crosstalk in multiple organs that mediate disease. This review focuses on the role of cardiac ketone metabolism in health and disease with an emphasis on the therapeutic potential of ketosis as a treatment for heart failure (HF). Cardiac metabolic reprogramming, characterized by diminished mitochondrial oxidative metabolism, contributes to cardiac dysfunction and pathologic remodeling during the development of HF. Growing evidence supports an adaptive role for ketone metabolism in HF to promote normal cardiac function and attenuate disease progression. Enhanced cardiac ketone utilization during HF is mediated by increased availability due to systemic ketosis and a cardiac autonomous upregulation of ketolytic enzymes. Therapeutic strategies designed to restore high-capacity fuel metabolism in the heart show promise to address fuel metabolic deficits that underpin the progression of HF. However, the mechanisms involved in the beneficial effects of ketone bodies in HF have yet to be defined and represent important future lines of inquiry. In addition to use as an energy substrate for cardiac mitochondrial oxidation, ketone bodies modulate myocardial utilization of glucose and fatty acids, two vital energy substrates that regulate cardiac function and hypertrophy. The salutary effects of ketone bodies during HF may also include extra-cardiac roles in modulating immune responses, reducing fibrosis, and promoting angiogenesis and vasodilation. Additional pleotropic signaling properties of beta-hydroxybutyrate and AcAc are discussed including epigenetic regulation and protection against oxidative stress. Evidence for the benefit and feasibility of therapeutic ketosis is examined in preclinical and clinical studies. Finally, ongoing clinical trials are reviewed for perspective on translation of ketone therapeutics for the treatment of HF.</AbstractText><br /><br /><br /><br /><small>Circ Res: 31 Mar 2023; 132:882-898</small></div>

<div><h4>ZBP1 Protects Against mtDNA-Induced Myocardial Inflammation in Failing Hearts.</h4><i>Enzan N, Matsushima S, Ikeda S, Okabe K, ... Kinugawa S, Tsutsui H</i><br /><b>Background</b><br />Mitochondrial DNA (mtDNA)-induced myocardial inflammation is intimately involved in cardiac remodeling. ZBP1 (Z-DNA binding protein 1) is a pattern recognition receptor positively regulating inflammation in response to mtDNA in inflammatory cells, fibroblasts, and endothelial cells. However, the role of ZBP1 in myocardial inflammation and cardiac remodeling remains unclear. The aim of this study was to elucidate the role of ZBP1 in mtDNA-induced inflammation in cardiomyocytes and failing hearts.<br /><b>Methods</b><br />mtDNA was administrated into isolated cardiomyocytes. Myocardial infarctionwas conducted in wild type and ZBP1 knockout mice.<br /><b>Results</b><br />We here found that, unlike in macrophages, ZBP1 knockdown unexpectedly exacerbated mtDNA-induced inflammation such as increases in IL (interleukin)-1β and IL-6, accompanied by increases in RIPK3 (receptor interacting protein kinase 3), phosphorylated NF-κB (nuclear factor-κB), and NLRP3 (nucleotide-binding domain and leucine-rich-repeat family pyrin domain containing 3) in cardiomyocytes. RIPK3 knockdown canceled further increases in phosphorylated NF-κB, NLRP3, IL-1β, and IL-6 by ZBP1 knockdown in cardiomyocytes in response to mtDNA. Furthermore, NF-κB knockdown suppressed such increases in NLRP3, IL-1β, and IL-6 by ZBP1 knockdown in response to mtDNA. CpG-oligodeoxynucleotide, a Toll-like receptor 9 stimulator, increased RIPK3, IL-1β, and IL-6 and ZBP1 knockdown exacerbated them. Dloop, a component of mtDNA, but not <i>Tert</i> and <i>B2m</i>, components of nuclear DNA, was increased in cytosolic fraction from noninfarcted region of mouse hearts after myocardial infarction compared with control hearts. Consistent with this change, ZBP1, RIPK3, phosphorylated NF-κB, NLRP3, IL-1β, and IL-6 were increased in failing hearts. ZBP1 knockout mice exacerbated left ventricular dilatation and dysfunction after myocardial infarction, accompanied by further increases in RIPK3, phosphorylated NF-κB, NLRP3, IL-1β, and IL-6. In histological analysis, ZBP1 knockout increased interstitial fibrosis and myocardial apoptosis in failing hearts.<br /><b>Conclusions</b><br />Our study reveals unexpected protective roles of ZBP1 against cardiac remodeling as an endogenous suppressor of mtDNA-induced myocardial inflammation.<br /><br /><br /><br /><small>Circ Res: 28 Mar 2023; epub ahead of print</small></div>

<div><h4>Enhanced Ca-Dependent SK-Channel Gating and Membrane Trafficking in Human Atrial Fibrillation.</h4><i>Heijman J, Zhou X, Morotti S, Molina CE, ... Nattel S, Dobrev D</i><br /><b>Background</b><br />Small-conductance Ca<sup>2+</sup>-activated K<sup>+</sup> (SK)-channel inhibitors have antiarrhythmic effects in animal models of atrial fibrillation (AF), presenting a potential novel antiarrhythmic option. However, the regulation of SK-channels in human atrial cardiomyocytes and its modification in patients with AF are poorly understood and were the object of this study.<br /><b>Methods and results</b><br />Apamin-sensitive SK-channel current (I<sub>SK</sub>) and action potentials were recorded in human right-atrial cardiomyocytes from sinus rhythm control (Ctl) patients or patients with (long-term persistent) chronic AF (cAF). I<sub>SK</sub> was significantly higher, and apamin caused larger action potential prolongation in cAF- versus Ctl- cardiomyocytes. Sensitivity analyses in an in silico human atrial cardiomyocyte model identified I<sub>K1</sub> and I<sub>SK</sub> as major regulators of repolarization. Increased I<sub>SK</sub> in cAF was not associated with increases in mRNA/protein levels of SK-channel subunits in either right- or left-atrial tissue homogenates or right-atrial cardiomyocytes, but the abundance of SK2 at the sarcolemma was larger in cAF versus Ctl in both tissue-slices and cardiomyocytes. Latrunculin-A and primaquine (anterograde and retrograde protein-trafficking inhibitors) eliminated the differences in SK2 membrane levels and I<sub>SK</sub> between Ctl- and cAF-cardiomyocytes. In addition, the phosphatase-inhibitor okadaic acid reduced I<sub>SK</sub> amplitude and abolished the difference between Ctl- and cAF-cardiomyocytes, indicating that reduced calmodulin-Thr80 phosphorylation due to increased protein phosphatase-2A levels in the SK-channel complex likely contribute to the greater I<sub>SK</sub> in cAF-cardiomyocytes. Finally, rapid electrical activation (5 Hz, 10 minutes) of Ctl-cardiomyocytes promoted SK2 membrane-localization, increased I<sub>SK</sub> and reduced action potential duration, effects greatly attenuated by apamin. Latrunculin-A or primaquine prevented the 5-Hz-induced I<sub>SK</sub>-upregulation.<br /><b>Conclusions</b><br />I<sub>SK</sub> is upregulated in patients with cAF due to enhanced channel function, mediated by phosphatase-2A-dependent calmodulin-Thr80 dephosphorylation and tachycardia-dependent enhanced trafficking and targeting of SK-channel subunits to the sarcolemma. The observed AF-associated increases in I<sub>SK</sub>, which promote reentry-stabilizing action potential duration shortening, suggest an important role for SK-channels in AF auto-promotion and provide a rationale for pursuing the antiarrhythmic effects of SK-channel inhibition in humans.<br /><br /><br /><br /><small>Circ Res: 17 Mar 2023; epub ahead of print</small></div>

<div><h4>Platelets at the Vessel Wall in Non-Thrombotic Disease.</h4><i>Aggarwal A, Jennings CL, Manning E, Cameron SJ</i><br /><AbstractText>Platelets are small, anucleate entities that bud from megakaryocytes in the bone marrow. Among circulating cells, platelets are the most abundant cell, traditionally involved in regulating the balance between thrombosis (the terminal event of platelet activation) and hemostasis (a protective response to tissue injury). Although platelets lack the precise cellular control offered by nucleate cells, they are in fact very dynamic cells, enriched in preformed RNA that allows them the capability of de novo protein synthesis which alters the platelet phenotype and responses in physiological and pathological events. Antiplatelet medications have significantly reduced the morbidity and mortality for patients afflicted with thrombotic diseases, including stroke and myocardial infarction. However, it has become apparent in the last few years that platelets play a critical role beyond thrombosis and hemostasis. For example, platelet-derived proteins by constitutive and regulated exocytosis can be found in the plasma and may educate distant tissue including blood vessels. First, platelets are enriched in inflammatory and anti-inflammatory molecules that may regulate vascular remodeling. Second, platelet-derived microparticles released into the circulation can be acquired by vascular endothelial cells through the process of endocytosis. Third, platelets are highly enriched in mitochondria that may contribute to the local reactive oxygen species pool and remodel phospholipids in the plasma membrane of blood vessels. Lastly, platelets are enriched in proteins and phosphoproteins which can be secreted independent of stimulation by surface receptor agonists in conditions of disturbed blood flow. This so-called biomechanical platelet activation occurs in regions of pathologically narrowed (atherosclerotic) or dilated (aneurysmal) vessels. Emerging evidence suggests platelets may regulate the process of angiogenesis and blood flow to tumors as well as education of distant organs for the purposes of allograft health following transplantation. This review will illustrate the potential of platelets to remodel blood vessels in various diseases with a focus on the aforementioned mechanisms.</AbstractText><br /><br /><br /><br /><small>Circ Res: 17 Mar 2023; 132:775-790</small></div>

<div><h4>Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities.</h4><i>Stotts C, Corrales-Medina VF, Rayner KJ</i><br /><AbstractText>Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.</AbstractText><br /><br /><br /><br /><small>Circ Res: 17 Mar 2023; 132:751-774</small></div>

<div><h4>Evidence That Binding of Cyclic GMP to the Extracellular Domain of Na/K-ATPase Mediates Natriuresis.</h4><i>Kemp BA, Howell NL, Gildea JJ, Hinkle JD, ... Keller SR, Carey RM</i><br /><b>Background</b><br />Extracellular renal interstitial cGMP inhibits renal proximal tubule (RPT) sodium (Na<sup>+</sup>) reabsorption via Src (Src family kinase) activation. Through which target extracellular cGMP acts to induce natriuresis is unknown. We hypothesized that cGMP binds to the extracellular α1-subunit of NKA (sodium-potassium ATPase) on RPT basolateral membranes to inhibit Na<sup>+</sup> transport similar to ouabain-a cardiotonic steroid.<br /><b>Methods and results</b><br />Urine Na<sup>+</sup> excretion was measured in uninephrectomized 12-week-old female Sprague-Dawley rats that received renal interstitial infusions of vehicle (5% dextrose in water), cGMP (18, 36, and 72 μg/kg per minute; 30 minutes each), or cGMP+rostafuroxin (12 ng/kg per minute) or were subjected to pressure-natriuresis±rostafuroxin infusion. Rostafuroxin is a digitoxigenin derivative that displaces ouabain from NKA. Renal interstitial cGMP and raised renal perfusion pressure induced natriuresis and increased phosphorylated Src<sup>Tyr416</sup> and Erk 1/2 (extracellular signal-regulated protein kinase 1/2)<sup>Thr202/Tyr204</sup>; these responses were abolished with rostafuroxin coinfusion. To assess cGMP binding to NKA, we performed competitive binding studies with isolated rat RPTs using bodipy-ouabain (2 μM)+cGMP (10 µM) or rostafuroxin (10 µM) and 8-biotin-11-cGMP (2 μM)+ouabain (10 μM) or rostafuroxin (10 µM). cGMP or rostafuroxin reduced bodipy-ouabain fluorescence intensity, and ouabain or rostafuroxin reduced 8-biotin-11-cGMP staining. We cross-linked isolated rat RPTs with 4-N<sub>3</sub>-PET-8-biotin-11-cGMP (2 μM); 8-N<sub>3</sub>-6-biotin-10-cAMP served as negative control. Precipitation with streptavidin beads followed by immunoblot analysis showed that RPTs after cross-linking with 4-N<sub>3</sub>-PET-8-biotin-11-cGMP exhibited a significantly stronger signal for NKA than non-cross-linked samples and cross-linked or non-cross-linked 8-N<sub>3</sub>-6-biotin-10-cAMP RPTs. Ouabain (10 μM) reduced NKA in cross-linked 4-N<sub>3</sub>-PET-8-biotin-11-cGMP RPTs confirming fluorescence staining. 4-N<sub>3</sub>-PET-8-biotin-11-cGMP cross-linked samples were separated by SDS gel electrophoresis and slices corresponding to NKA molecular weight excised and processed for mass spectrometry. NKA was the second most abundant protein with 50 unique NKA peptides covering 47% of amino acids in NKA. Molecular modeling demonstrated a potential cGMP docking site in the ouabain-binding pocket of NKA.<br /><b>Conclusions</b><br />cGMP can bind to NKA and thereby mediate natriuresis.<br /><br /><br /><br /><small>Circ Res: 15 Mar 2023; epub ahead of print</small></div>

<div><h4>Expression of Concern: Membrane Shedding of Epidermal Growth Factor Is Required for Cardiomyocyte Anoikis.</h4><i></i><br /><AbstractText>The Editors of <i>Circulation Research</i> are issuing an Expression of Concern regarding article, \"Membrane Shedding of Epidermal Growth Factor Is Required for Cardiomyocyte Anoikis\" which originally published November 1, 2007, and appeared in the January 4, 2008, issue of the journal (<i>Circulation Research</i>. 2008;102:32-41. doi: 10.1161/CIRCRESAHA.107.150573). Concerns have been raised regarding the quality of data and multiple images in the above-referenced article. The editors and Scientific Publishing Committee are in communication with the authors regarding the integrity of the image data, and Temple University has confirmed the concerns are being assessed. While we await the outcome of this assessment, we are publishing this Expression of Concern to indicate that the data and statements in the article may not be reliable.</AbstractText><br /><br /><br /><br /><small>Circ Res: 13 Mar 2023; epub ahead of print</small></div>

<div><h4>Expression of Concern: Sympathetic Activation Causes Focal Adhesion Signaling Alteration in Early Compensated Volume Overload Attributable to Isolated Mitral Regurgitation in the Dog.</h4><i></i><br /><AbstractText>The Editors of <i>Circulation Research</i> are issuing an Expression of Concern regarding article, \"Sympathetic Activation Causes Focal Adhesion Signaling Alteration in Early Compensated Volume Overload Attributable to Isolated Mitral Regurgitation in the Dog\" which originally published March 20, 2008, and appeared in the May 9, 2008, issue of the journal (<i>Circulation Research</i>. 2008;102:1127-1136. doi: 10.1161/CIRCRESAHA.107.163642). Concerns have been raised regarding the quality of data and multiple images in the above-referenced article. The editors and Scientific Publishing Committee are in communication with the authors regarding the integrity of the image data, and Temple University has confirmed the concerns are being assessed. While we await the outcome of this assessment, we are publishing this Expression of Concern to indicate that the data and statements in the article may not be reliable.</AbstractText><br /><br /><br /><br /><small>Circ Res: 13 Mar 2023; epub ahead of print</small></div>

<div><h4>Platelet-Derived MicroRNAs Regulate Cardiac Remodeling After Myocardial Ischemia.</h4><i>Philipp Schütte J, Manke MC, Hemmen K, Münzer P, ... Casadei N, Borst O</i><br /><b>Background</b><br />Platelets can infiltrate ischemic myocardium and are increasingly recognized as critical regulators of inflammatory processes during myocardial ischemia and reperfusion (I/R). Platelets contain a broad repertoire of microRNAs (miRNAs), which, under certain conditions such as myocardial ischemia, may be transferred to surrounding cells or released into the microenvironment. Recent studies could demonstrate that platelets contribute substantially to the circulating miRNA pool holding the potential for so far undiscovered regulatory functions. The present study aimed to determine the role of platelet-derived miRNAs in myocardial injury and repair following myocardial I/R.<br /><b>Methods</b><br />In vivo model of myocardial I/R, multimodal in vivo and ex vivo imaging approaches (light-sheet fluorescence microscopy, positron emission tomography and magnetic resonance imaging, speckle-tracking echocardiography) of myocardial inflammation and remodeling, and next-generation deep sequencing analysis of platelet miRNA expression.<br /><b>Results</b><br />In mice with a megakaryocyte/platelet-specific knockout of pre-miRNA processing ribonuclease Dicer, the present study discloses a key role of platelet-derived miRNAs in the tightly regulated cellular processes orchestrating left ventricular remodeling after myocardial I/R following transient left coronary artery ligation. Disruption of the miRNA processing machinery in platelets by deletion of Dicer resulted in increased myocardial inflammation, impaired angiogenesis, and accelerated development of cardiac fibrosis, culminating in an increased infarct size by d7 that persisted through d28 of myocardial I/R. Worsened cardiac remodeling after myocardial infarction in mice with a platelet-specific Dicer deletion resulted in an increased fibrotic scar formation and distinguishably increased perfusion defect of the apical and anterolateral wall at day 28 post-myocardial infarction. Altogether, these observations culminated in an impaired left ventricular function and hampered long-term cardiac recovery after experimental myocardial infarction and reperfusion therapy. Treatment with the P2Y<sub>12</sub> antagonist ticagrelor completely reversed increased myocardial damage and adverse cardiac remodeling observed in <i>Dicer</i><sup><i>Pf4∆/Pf4∆</i></sup> mice.<br /><b>Conclusions</b><br />The present study discloses a critical role of platelet-derived miRNA in myocardial inflammation and structural remodeling processes following myocardial I/R.<br /><br /><br /><br /><small>Circ Res: 09 Mar 2023; epub ahead of print</small></div>

<div><h4>β3AR-Dependent BDNF (Brain-Derived Neurotrophic Factor) Generation Limits Chronic Postischemic Heart Failure.</h4><i>Cannavo A, Jun S, Rengo G, Marzano F, ... Koch WJ, Paolocci N</i><br /><b>Background</b><br />Loss of brain-derived neurotrophic factor (BDNF)/TrkB (tropomyosin kinase receptor B) signaling accounts for brain and cardiac disorders. In neurons, β-adrenergic receptor stimulation enhances local BDNF expression. It is unclear if this occurs in a pathophysiological relevant manner in the heart, especially in the β-adrenergic receptor-desensitized postischemic myocardium. Nor is it fully understood whether and how TrkB agonists counter chronic postischemic left ventricle (LV) decompensation, a significant unmet clinical milestone.<br /><b>Methods</b><br />We conducted in vitro studies using neonatal rat and adult murine cardiomyocytes, SH-SY5Y neuronal cells, and umbilical vein endothelial cells. We assessed myocardial ischemia (MI) impact in WT, β3AR KO, or myocyte-selective BDNF KO (myoBDNF KO) mice in vivo (via coronary ligation [MI]) or in isolated hearts with global ischemia-reperfusion (I/R).<br /><b>Results</b><br />In WT hearts, BDNF levels rose early after MI (<24 hours), plummeting at 4 weeks when LV dysfunction, adrenergic denervation, and impaired angiogenesis ensued. The TrkB agonist, LM22A-4, countered all these adverse effects. Compared with WT, isolated myoBDNF KO hearts displayed worse infarct size/LV dysfunction after I/R injury and modest benefits from LM22A-4. In vitro, LM22A-4 promoted neurite outgrowth and neovascularization, boosting myocyte function, effects reproduced by 7,8-dihydroxyflavone, a chemically unrelated TrkB agonist. Superfusing myocytes with the β3AR-agonist, BRL-37344, increased myocyte BDNF content, while β3AR signaling underscored BDNF generation/protection in post-MI hearts. Accordingly, the β1AR blocker, metoprolol, via upregulated β3ARs, improved chronic post-MI LV dysfunction, enriching the myocardium with BDNF. Last, BRL-37344-imparted benefits were nearly abolished in isolated I/R injured myoBDNF KO hearts.<br /><b>Conclusions</b><br />BDNF loss underscores chronic postischemic heart failure. TrkB agonists can improve ischemic LV dysfunction via replenished myocardial BDNF content. Direct cardiac β3AR stimulation, or β-blockers (via upregulated β3AR), is another BDNF-based means to fend off chronic postischemic heart failure.<br /><br /><br /><br /><small>Circ Res: 08 Mar 2023; epub ahead of print</small></div>

<div><h4>Integrated Proteomics Unveils Nuclear PDE3A2 as a Regulator of Cardiac Myocyte Hypertrophy.</h4><i>Subramaniam G, Schleicher K, Kovanich D, Zerio A, ... Mohammed S, Zaccolo M</i><br /><b>Background</b><br />Signaling by cAMP is organized in multiple distinct subcellular nanodomains regulated by cAMP-hydrolyzing PDEs (phosphodiesterases). Cardiac β-adrenergic signaling has served as the prototypical system to elucidate cAMP compartmentalization. Although studies in cardiac myocytes have provided an understanding of the location and properties of a handful of cAMP subcellular compartments, an overall view of the cellular landscape of cAMP nanodomains is missing.<br /><b>Methods</b><br />Here, we combined an integrated phosphoproteomics approach that takes advantage of the unique role that individual PDEs play in the control of local cAMP, with network analysis to identify previously unrecognized cAMP nanodomains associated with β-adrenergic stimulation. We then validated the composition and function of one of these nanodomains using biochemical, pharmacological, and genetic approaches and cardiac myocytes from both rodents and humans.<br /><b>Results</b><br />We demonstrate the validity of the integrated phosphoproteomic strategy to pinpoint the location and provide critical cues to determine the function of previously unknown cAMP nanodomains. We characterize in detail one such compartment and demonstrate that the PDE3A2 isoform operates in a nuclear nanodomain that involves SMAD4 (SMAD family member 4) and HDAC-1. Inhibition of PDE3 results in increased HDAC-1 phosphorylation, leading to inhibition of its deacetylase activity, derepression of gene transcription, and cardiac myocyte hypertrophic growth.<br /><b>Conclusions</b><br />We developed a strategy for detailed mapping of subcellular PDE-specific cAMP nanodomains. Our findings reveal a mechanism that explains the negative long-term clinical outcome observed in patients with heart failure treated with PDE3 inhibitors.<br /><br /><br /><br /><small>Circ Res: 08 Mar 2023; epub ahead of print</small></div>

<div><h4>Destabilization of Atherosclerotic Plaque by Bilirubin Deficiency.</h4><i>Chen W, Tumanov S, Stanley CP, Kong SMY, ... Dunn LL, Stocker R</i><br /><b>Background</b><br />The rupture of atherosclerotic plaque contributes significantly to cardiovascular disease. Plasma concentrations of bilirubin-a byproduct of heme catabolism-inversely associate with risk of cardiovascular disease, although the link between bilirubin and atherosclerosis remains unclear.<br /><b>Methods</b><br />To assess the role of bilirubin in atherosclerotic plaque stability, we crossed <i>Bvra</i><sup>-/-</sup> with <i>Apoe</i><sup>-/</sup><sup>-</sup> mice and used the tandem stenosis model of plaque instability. Human coronary arteries were obtained from heart transplant recipients. Analysis of bile pigments, heme metabolism, and proteomics were performed by liquid chromatography tandem mass spectrometry. MPO (myeloperoxidase) activity was determined by in vivo molecular magnetic resonance imaging, liquid chromatography tandem mass spectrometry analysis, and immunohistochemical determination of chlorotyrosine. Systemic oxidative stress was evaluated by plasma concentrations of lipid hydroperoxides and the redox status of circulating Prx2 (peroxiredoxin-2), whereas arterial function was assessed by wire myography. Atherosclerosis and arterial remodeling were quantified by morphometry and plaque stability by fibrous cap thickness, lipid accumulation, infiltration of inflammatory cells, and the presence of intraplaque hemorrhage.<br /><b>Results</b><br />Compared with <i>Bvra<sup>+/</sup>Apoe</i><sup>-/-</sup> tandem stenosis littermates, <i>Bvra</i><sup>-/-</sup><i>Apoe</i><sup>-/-</sup> tandem stenosis mice were deficient in bilirubin, showed signs of increased systemic oxidative stress, endothelial dysfunction, as well as hyperlipidemia, and had a higher atherosclerotic plaque burden. Heme metabolism was increased in unstable compared with stable plaque of both <i>Bvra<sup>+/</sup>Apoe</i><sup>-/-</sup> and <i>Bvra</i><sup>-/-</sup><i>Apoe</i><sup>-/-</sup> tandem stenosis mice and in human coronary plaques. In mice, <i>Bvra</i> deletion selectively destabilized unstable plaque, characterized by positive arterial remodeling and increased cap thinning, intraplaque hemorrhage, infiltration of neutrophils, and MPO activity. Proteomic analysis confirmed <i>Bvra</i> deletion enhanced extracellular matrix degradation, recruitment and activation of neutrophils, and associated oxidative stress in unstable plaque.<br /><b>Conclusions</b><br />Bilirubin deficiency, resulting from global <i>Bvra</i> deletion, generates a proatherogenic phenotype and selectively enhances neutrophil-mediated inflammation and destabilization of unstable plaque, thereby providing a link between bilirubin and cardiovascular disease risk.<br /><br /><br /><br /><small>Circ Res: 06 Mar 2023; epub ahead of print</small></div>

<div><h4>RNF130 Regulates LDLR Availability and Plasma LDL Cholesterol Levels.</h4><i>Clifford BL, Jarrett KE, Cheng J, Cheng A, ... de Aguiar Vallim TQ, Tarling EJ</i><br /><b>Background</b><br />Removal of circulating plasma LDL-C (low-density lipoprotein cholesterol) by the liver relies on efficient endocytosis and intracellular vesicle trafficking. Increasing the availability of hepatic LDLRs (LDL receptors) remains a major clinical target for reducing LDL-C levels. Here, we describe a novel role for RNF130 (ring finger containing protein 130) in regulating plasma membrane availability of LDLR.<br /><b>Methods</b><br />We performed a combination of gain-of-function and loss-of-function experiments to determine the effect of RNF130 on LDL-C and LDLR recycling. We overexpressed RNF130 and a nonfunctional mutant RNF130 in vivo and measured plasma LDL-C and hepatic LDLR protein levels. We performed in vitro ubiquitination assays and immunohistochemical staining to measure levels and cellular distribution of LDLR. We supplement these experiments with 3 separate in vivo models of RNF130 loss-of-function where we disrupted <i>Rnf130</i> using either antisense oligonucleotides, germline deletion, or adeno-associated virus clustered regularly interspaced short palindromic repeats and measured hepatic LDLR and plasma LDL-C.<br /><b>Results</b><br />We demonstrate that RNF130 is an E3 ubiquitin ligase that ubiquitinates LDLR resulting in redistribution of the receptor away from the plasma membrane. Overexpression of RNF130 decreases hepatic LDLR and increases plasma LDL-C levels. Further, in vitro ubiquitination assays demonstrate really interesting new gene-dependent regulation of LDLR abundance at the plasma membrane. Finally, in vivo disruption of <i>Rnf130</i> using antisense oligonucleotides, germline deletion, or adeno-associated virus clustered regularly interspaced short palindromic repeats results in increased hepatic LDLR abundance and availability and decreased plasma LDL-C levels.<br /><b>Conclusions</b><br />Our studies identify RNF130 as a novel posttranslational regulator of LDL-C levels via modulation of LDLR availability, thus providing important insight into the complex regulation of hepatic LDLR protein levels.<br /><br /><br /><br /><small>Circ Res: 06 Mar 2023; epub ahead of print</small></div>

<div><h4>Wearable Devices in Cardiovascular Medicine.</h4><i>Hughes A, Shandhi MMH, Master H, Dunn J, Brittain E</i><br /><AbstractText>Wearable devices, such as smartwatches and activity trackers, are commonly used by patients in their everyday lives to manage their health and well-being. These devices collect and analyze long-term continuous data on measures of behavioral or physiologic function, which may provide clinicians with a more comprehensive view of a patients\' health compared with the traditional sporadic measures captured by office visits and hospitalizations. Wearable devices have a wide range of potential clinical applications ranging from arrhythmia screening of high-risk individuals to remote management of chronic conditions such as heart failure or peripheral artery disease. As the use of wearable devices continues to grow, we must adopt a multifaceted approach with collaboration among all key stakeholders to effectively and safely integrate these technologies into routine clinical practice. In this Review, we summarize the features of wearable devices and associated machine learning techniques. We describe key research studies that illustrate the role of wearable devices in the screening and management of cardiovascular conditions and identify directions for future research. Last, we highlight the challenges that are currently hindering the widespread use of wearable devices in cardiovascular medicine and provide short- and long-term solutions to promote increased use of wearable devices in clinical care.</AbstractText><br /><br /><br /><br /><small>Circ Res: 03 Mar 2023; 132:652-670</small></div>