The Hatter Cardiovascular Institute, University College London, London, UK.
Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile.
J Cell Mol Med. 2018 Feb;22(2):926-935. doi: 10.1111/jcmm.13394. Epub 2017 Nov 20.
The Reperfusion Injury Salvage Kinase (RISK) pathway is considered the main pro-survival kinase cascade mediating the ischaemic preconditioning (IPC) cardioprotective effect. To assess the role of PI3K-Akt, its negative regulator PTEN and other pro-survival proteins such as ERK and STAT3 in the context of IPC, C57BL/6 mouse hearts were retrogradely perfused in a Langendorff system and subjected to 4 cycles of 5 min. ischaemia and 5 min. reperfusion prior to 35 min. of global ischaemia and 120 min. of reperfusion. Wortmannin, a PI3K inhibitor, was administered either at the stabilization period or during reperfusion. Infarct size was assessed using triphenyl tetrazolium staining, and phosphorylation levels of Akt, PTEN, ERK, GSK3β and STAT3 were evaluated using Western blot analyses. IPC reduced infarct size in hearts subjected to lethal ischaemia and reperfusion, but this effect was lost in the presence of Wortmannin, whether it was present only during preconditioning or only during early reperfusion. IPC increased the levels of Akt phosphorylation during both phases and this effect was fully abrogated by PI3K, whilst its downstream GSK3β was phosphorylated only during the trigger phase after IPC. Both PTEN and STAT3 were phosphorylated during both phases after IPC, but this was PI3K independent. IPC increases ERK phosphorylation during both phases, being only PI3K-dependent during the IPC phase. In conclusion, PI3K-Akt plays a major role in IPC-induced cardioprotection. However, PTEN, ERK and STAT3 are also phosphorylated by IPC through a PI3K-independent pathway, suggesting that cardioprotection is mediated through more than one cell signalling cascade.
再灌注损伤 salvage 激酶 (RISK) 途径被认为是介导缺血预处理 (IPC) 心脏保护作用的主要生存激酶级联。为了评估 PI3K-Akt、其负调节因子 PTEN 和其他生存蛋白（如 ERK 和 STAT3）在 IPC 中的作用，C57BL/6 小鼠心脏在 Langendorff 系统中逆行灌注，并在 35 分钟的全缺血和 120 分钟的再灌注之前进行 4 个 5 分钟的缺血和 5 分钟的再灌注循环。PI3K 抑制剂 Wortmannin 在稳定期或再灌注期给药。使用三苯基四唑染色评估梗塞面积，并用 Western blot 分析评估 Akt、PTEN、ERK、GSK3β 和 STAT3 的磷酸化水平。IPC 减少了致命缺血和再灌注后心脏的梗塞面积，但在 Wortmannin 存在下，这种作用消失了，无论它仅存在于预处理期间还是仅存在于早期再灌注期间。IPC 增加了两个阶段 Akt 磷酸化水平，而这种作用完全被 PI3K 阻断，而其下游 GSK3β 仅在 IPC 后的触发阶段被磷酸化。IPC 后两个阶段都有 PTEN 和 STAT3 磷酸化，但这是 PI3K 非依赖性的。IPC 在两个阶段都增加了 ERK 磷酸化，仅在 IPC 阶段依赖于 PI3K。总之，PI3K-Akt 在 IPC 诱导的心脏保护中起主要作用。然而，PTEN、ERK 和 STAT3 也通过 PI3K 非依赖性途径被 IPC 磷酸化，表明心脏保护是通过不止一条细胞信号级联介导的。
