哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)是一种保守、非典型的丝氨酸/氨酸蛋白激酶,其主要通过复合体1(m TOR complex 1,m TORC1)和复合体2(m TOR complex 2,m TORC2)发挥作用。有研究证实,复合体1在心肌缺血期和再灌注期分别起到了不同的重要作用,通过调控复合体1可以影响细胞自噬水平、线粒体通透性转换孔的开放、抗氧化基因的上调等机制起到保护心肌的作用。本文对m TOR复合体的结构,以及m TORC1信号分别在心肌缺血期和再灌注期的作用机制进行综述。
Cannabinoid receptor type 2(CB2)activation is recently reported to promote proliferation of some types of resident stem cells(e.g.,hematopoietic stem/progenitor cell or neural progenitor cell).Resident cardiac progenitor cell(CPC)activation and proliferation are crucial for endogenous cardiac regeneration and cardiac repair after myocardial infarction(MI).This study aims to explore the role and possible mechanisms of CB2receptor activation in enhancing myocardial repair.Our results revealed that CB2receptor agonist AM1241 can significantly increase CPCs by c-kit and Runx1 staining in ischemic myocardium as well as improve cardiomyocyte proliferation.AM1241 also decreased serum levels of MDA,TNF-αand IL-6 after MI.In addition,AM1241 can ameliorate left ventricular ejection fraction and fractional shortening,and reduce fibrosis.Moreover,AM1241 treatment markedly increased p-Akt and HO-1 expression,and promoted Nrf-2 nuclear translocation.However,PI3K inhibitor wortmannin eliminated these cardioprotective roles of AM1241.In conclusion,AM1241 could induce myocardial regeneration and improve cardiac function,which might be associated with PI3K/Akt/Nrf2 signaling pathway activation.Our findings may provide a promising strategy for cardiac endogenous regeneration after MI.
