Abstract 15001: Stimulation of P2Y11 Receptor Affords Cardioprotection Against Hypoxia/Reoxygenation Injury in Cultured Cardiomyocytes and Improves Allogeneic Heart Graft Survival
Ischemia reperfusion injuries are involved in the physiopathology of heart transplantation where they will increase graft rejection. Ischemia generates cellular stress leading to ATP release in the extracellular medium that may activate purinergic receptors. These receptors may play important regulatory roles. We already showed that the purinergic receptor P2Y11 (P2Y11R) exhibited an immunosuppressive role in human dendritic cells in vitro (Chadet et al., 2015). We sought here for a possible role of P2Y11R in the cellular response of cardiomyocytes to ischemia/reperfusion. We used a human cell line of adult ventricular cardiomyocytes (AC16) and a rat cardiomyoblast cell line (H9c2). Both were subjected to 5h of hypoxia (1% O2, PBS) and 1h of reoxygenation (21% O2, DMEM) (H/R). Viability/mortality was assessed by MTT Assay, ATPi level and LDH release. We then confirmed our in vitro data in an in vivo model of allogeneic heterotopic heart transplantation in mice. Hearts from BalbC mice were intra-abdominally transplanted into C57BL6 mice. Graft survival, a surrogate marker of rejection, was evaluated by subcutaneous heartbeat palpation and confirmed by echocardiography. Addition of ATP (100 μM) in vitro at the onset of reoxygenation decreased AC16 cell death independently of adenosine receptors (-14%±2%, p<0.05), supporting the involvement of P2Y11R in cardiomyocytes response to H/R. In addition, pharmacological postconditioning with NF546, a specific P2Y11R agonist, in both AC16 and H9c2 induced significant protection with regards to cell viability (respectively +15%±5% and +12%±3%, p<0.05). This protection was suppressed by the P2Y11R antagonist NF340 suggesting a cardioprotective role of P2Y11R stimulation against H/R injuries in vitro. We then injected heart transplanted mice in the retro-orbital sinus with NF546. Cardiac allograft survival was significantly prolonged after NF546 injection compared to saline (9.6±1.9 vs. 8.2±1.4 days, p=0.04) suggesting an in vivo protection by P2Y11R stimulation. Our data strongly suggest that P2Y11R may modulate myocardial H/R injuries and subsequently heart graft rejection. Future experiments will aim at investigating the molecular mechanisms of this protection.
Author Disclosures: L. Benoist: None. T. Bourguignon: None. T. Genet: None. S. Chadet: None. C. Lefort: None. C. Baron: None. D. Babuty: None. D. Angoulvant: None. F. Ivanes: None.
- © 2016 by American Heart Association, Inc.