Inhibition of adenosine kinase attenuates myocardial ischaemia/reperfusion injury.

Increased adenosine helps limit infarct size in ischaemia/reperfusion‐injured hearts. In cardiomyocytes, 90% of adenosine is catalysed by adenosine kinase (ADK) and ADK inhibition leads to higher concentrations of both intracellular adenosine and extracellular adenosine. However, the role of ADK inhibition in myocardial ischaemia/reperfusion (I/R) injury remains less obvious. We explored the role of ADK inhibition in myocardial I/R injury using mouse left anterior ligation model. To inhibit ADK, the inhibitor ABT‐702 was intraperitoneally injected or AAV9 (adeno‐associated virus)—ADK—shRNA was introduced via tail vein injection. H9c2 cells were exposed to hypoxia/reoxygenation (H/R) to elucidate the underlying mechanisms. ADK was transiently increased after myocardial I/R injury. Pharmacological or genetic ADK inhibition reduced infarct size, improved cardiac function and prevented cell apoptosis and necroptosis in I/R‐injured mouse hearts. In vitro, ADK inhibition also prevented cell apoptosis and cell necroptosis in H/R‐treated H9c2 cells. Cleaved caspase‐9, cleaved caspase‐8, cleaved caspase‐3, MLKL and the phosphorylation of MLKL and CaMKII were decreased by ADK inhibition in reperfusion‐injured cardiomyocytes. X‐linked inhibitor of apoptosis protein (XIAP), which is phosphorylated and stabilized via the adenosine receptors A2B and A1/Akt pathways, should play a central role in the effects of ADK inhibition on cell apoptosis and necroptosis. These data suggest that ADK plays an important role in myocardial I/R injury by regulating cell apoptosis and necroptosis.

增加的腺苷有助于限制缺血/再灌注损伤心脏的梗死面积。在心肌细胞中，90%的腺苷由腺苷激酶（ADK）催化，抑制ADK会导致细胞内和细胞外腺苷浓度升高。然而，抑制ADK在心肌缺血/再灌注（I/R）损伤中的作用仍不十分明确。我们利用小鼠左前降支结扎模型探讨了抑制ADK在心肌I/R损伤中的作用。为了抑制ADK，通过腹腔注射抑制剂ABT - 702或经尾静脉注射腺相关病毒9（AAV9） - ADK - 短发夹RNA（shRNA）。将H9c2细胞暴露于缺氧/复氧（H/R）环境以阐明潜在机制。心肌I/R损伤后ADK短暂升高。药物或基因抑制ADK可减小梗死面积，改善心脏功能，并防止I/R损伤小鼠心脏中的细胞凋亡和坏死性凋亡。在体外，抑制ADK也可防止H/R处理的H9c2细胞发生细胞凋亡和坏死性凋亡。在再灌注损伤的心肌细胞中，抑制ADK可降低裂解的半胱天冬酶 - 9、裂解的半胱天冬酶 - 8、裂解的半胱天冬酶 - 3、混合谱系激酶结构域样蛋白（MLKL）以及MLKL和钙/钙调蛋白依赖性蛋白激酶II（CaMKII）的磷酸化。X连锁凋亡抑制蛋白（XIAP）通过腺苷受体A2B和A1/Akt途径磷酸化并稳定，应在抑制ADK对细胞凋亡和坏死性凋亡的影响中起核心作用。这些数据表明，ADK通过调节细胞凋亡和坏死性凋亡在心肌I/R损伤中起重要作用。