成纤维细胞生长因子10通过激活AMPK/mTOR/TFEB信号通路减轻心肌缺血再灌注损伤OA

AIM:To explore the protective role and underlying molecular mechanism of fibroblast growth fac-tor 10(FGF10)in myocardial ischemia/reperfusion injury(MIRI).METHODS:A in vivo model of MIRI was estab-lished in C57BL/6 mice,and an in vitro model of hypoxia/reoxygenation(H/R)injury was constructed in neonatal rat car-diomyocytes.Changes in the expression levels of FGF10 at different reperfusion/reoxygenation time points were evaluated in both models.After treatment with exogenous recombinant FGF10,cardiac function and myocardial infarct size were as-sessed using echocardiography and 2,3,5-triphenyltetrazolium chloride/Evans blue double staining in the mice,while apoptosis and fibrosis were evaluated in cardiomyocytes using TUNEL staining and Masson staining.The levels of apopto-sis-related proteins[caspase-3,B-cell leukemia/lymphoma-2(Bcl-2)and Bcl-2-associated X protein(Bax)]and autopha-gy markers[microtubule-associated protein 1 light chain 3-II(LC3-II)and P62]were assessed using Western blot.Mice were treated with the autophagy inhibitor chloroquine or the autophagy agonist rapamycin,while cardiomyocytes were incu-bated with the lysosomal inhibitor bafilomycin A1 in combination with mCherry-GFP-LC3 adenovirus to monitor autophagic flux.The roles of AMP-activated protein kinase(AMPK)pathway,transcription factor EB(TFEB)nuclear translocation,and lysosomal-related gene transcription in FGF10-mediated regulation of autophagic flux were investigated using the AMPK-specific inhibitor Compound C,as well as Western blot,nuclear-cytoplasmic protein fractionation,and RT-qPCR.RESULTS:The FGF10 expression was significantly increased in both MIRI hearts and H/R cardiomyocytes,accompa-nied by LC3-II and P62 accumulation and blockade of autophagic flux(P<0.01).FGF10 significantly improved the left ventricular ejection fraction and fractional shortening(P<0.01),reduced myocardial infarct size,decreased cardiomyo-cyte apoptosis,and attenuated myocardial fibrosis(P<0.01).Mechanistic studies revealed that MIRI reduced AMPK ac-tivity and excessive mammalian target of rapamycin(mTOR)activation,but increased both TFEB phosphorylation and its cytoplasmic retention.FGF10 was found to activate AMPK,inhibit mTOR phosphorylation,promote TFEB nuclear trans-location,restore lysosomal function,and increase autophagic flux(P<0.01).The cardioprotective effects of FGF10 were completely reversed by treatment with the AMPK inhibitor dorsomorphin(P<0.01).CONCLUSION:The FGF10 attenu-ates myocardial ischemia/reperfusion injury in mice.Mechanistically,FGF10 activates the AMPK/mTOR/TFEB pathway to restore autophagic flux and reduce cardiomyocyte apoptosis and fibrosis.