NAADP/SERCA3-Dependent Ca2+ Stores Pathway Specifically Controls Early Autocrine ADP Secretion Potentiating Platelet Activation

Circ Res. 2020 Sep 11;127(7):e166-e183. doi: 10.1161/CIRCRESAHA.119.316090. Epub 2020 Jun 26.

Abstract

Rationale: Ca2+ signaling is a key and ubiquitous actor of cell organization and its modulation controls many cellular responses. SERCAs (sarco-endoplasmic reticulum Ca2+-ATPases) pump Ca2+ into internal stores that play a major role in the cytosolic Ca2+ concentration rise upon cell activation. Platelets exhibit 2 types of SERCAs, SERCA2b and SERCA3 (SERCA3 deficient mice), which may exert specific roles, yet ill-defined. We have recently shown that Ca2+ mobilization from SERCA3-dependent stores was required for full platelet activation in weak stimulation conditions.

Objective: To uncover the signaling mechanisms associated with Ca2+ mobilization from SERCA3-dependent stores leading to ADP secretion.

Methods and results: Using platelets from wild-type or Serca3-deficient mice, we demonstrated that an early (within 5-10 s following stimulation) secretion of ADP specifically dependent on SERCA3 stored Ca2+ is exclusively mobilized by nicotinic acid adenosine dinucleotide-phosphate (NAADP): both Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion are blocked by the NAADP receptor antagonist Ned-19, and reciprocally both are stimulated by permeant NAADP. In contrast, Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion were unaffected by inhibition of the production of IP3 (inositol-1,4,5-trisphosphate) by phospholipase-C and accordingly were not stimulated by permeant IP3.

Conclusions: Upon activation, an NAADP/SERCA3 Ca2+ mobilization pathway initiates an early ADP secretion, potentiating platelet activation, and a secondary wave of ADP secretion driven by both an IP3/SERCA2b-dependent Ca2+ stores pathway and the NAADP/SERCA3 pathway. This does not exclude that Ca2+ mobilized from SERCA3 stores may also enhance platelet global reactivity to agonists. Because of its modulating effect on platelet activation, this NAADP-SERCA3 pathway may be a relevant target for anti-thrombotic therapy. Graphic Abstract: A graphic abstract is available for this article.

Keywords: adenosine; endoplasmic reticulum; platelet activation; sarcoplasmic reticulum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / blood*
  • Animals
  • Autocrine Communication* / drug effects
  • Blood Platelets / drug effects
  • Blood Platelets / enzymology*
  • Calcium Signaling* / drug effects
  • Humans
  • Inositol 1,4,5-Trisphosphate / blood
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NADP / analogs & derivatives*
  • NADP / blood
  • Platelet Activation* / drug effects
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases / blood*
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases / genetics
  • Secretory Pathway
  • Thrombin / pharmacology
  • Thromboxane A2 / blood
  • Time Factors

Substances

  • NADP
  • NAADP
  • Thromboxane A2
  • Adenosine Diphosphate
  • Inositol 1,4,5-Trisphosphate
  • Thrombin
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases
  • ATP2A3 protein, human
  • Atp2a3 protein, mouse