The role of P2Y12 in cardiovascular disease beyond atherothrombosis: P2Y12 signaling promotes emergency hematopoiesis after myocardial infarction

Abstract

Abstract Background Adenosine diphosphate (ADP) plays a pivotal role in platelet activation. The purinergic ADP-receptor P2Y12 has therefore been targeted in the treatment of cardiovascular disease (CVD) to prevent atherothrombosis (1). Beyond P2Y12 expression on platelets, purinergic receptors have also been described on hematopoietic stem and progenitor cells (LSK) (2). After myocardial infarction (MI), accelerated LSK proliferation launches emergency hematopoiesis as the driving force behind the inflammatory response to MI, increasing inflammatory cell production in the bone marrow (BM) and providing leukocyte resupply for local cell recruitment to the infarct (3). The inflammatory cascade after MI covers intricate multilayered interactions between the injured myocardium and the hematopoietic BM that still remain to be fully elucidated and may unearth novel therapeutic strategies. Whereas P2X receptors have recently been found to be involved in cell trafficking (4), the role of P2Y receptors in the hematopoietic BM have not yet been characterized. Purpose This study aims to characterize the influence of P2Y12 signaling on emergency hematopoiesis and cardiac remodeling after MI. Methods Permanent coronary ligation was performed for MI to assess BM activation, inflammatory cell composition, cardiac remodeling and function in murine global and platelet-specific P2Y12 knockout models and under pharmacological P2Y12 inhibition with prasugrel using flow cytometry, qPCR, immunohistochemistry and echocardiography. In vitro studies including colony forming unit (CFU) assays and flow cytometry allowed for investigation of ADP-dependent effects on LSK cells and intracellular pathway analysis. Results We identified ADP as a danger signal for the hematopoietic BM, fueling emergency hematopoiesis by promoting Akt phosphorylation and cell cycle progression. Detection of P2Y12 expression in LSK implicated a direct effect of ADP on LSK via P2Y12 signaling. P2Y12 deficiency and P2Y12 inhibition with prasugrel decelerated emergency hematopoiesis and consecutively reduced the excessive inflammatory response to MI, translating to lower numbers of hematopoietic progenitors and inflammatory cells in the blood and infarct. Ultimately, P2Y12 inhibition ameliorated chronic adverse cardiac remodeling and preserved cardiac function after MI. Conclusion ADP-dependent P2Y12-mediated activation of hematopoietic stem and progenitor cells in the BM promotes emergency hematopoiesis after MI and fuels post-ischemic inflammation, proposing a novel role of P2Y12 antagonists in CVD beyond atherothrombosis. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG)