Regulation of autophagy of the heart in ischemia and reperfusion.

ABSTRACT

Ischemia/reperfusion (I/R) of the heart leads to increased autophagic flux. Preconditioning stimulates autophagic flux by AMPK and PI3-kinase activation and mTOR inhibition. The cardioprotective effect of postconditioning is associated with activation of autophagy and increased activity of NO-synthase and AMPK. Oxidative stress stimulates autophagy in the heart during I/R. Superoxide radicals generated by NADPH-oxidase acts as a trigger for autophagy, possibly due to AMPK activation. There is reason to believe that AMPK, GSK-3ß, PINK1, JNK, hexokinase II, MEK, PKCα, and ERK kinases stimulate autophagy, while mTOR, PKCδ, Akt, and PI3-kinase can inhibit autophagy in the heart during I/R. However, there is evidence that PI3-kinase could stimulate autophagy in ischemic preconditioning of the heart. It was found that transcription factors FoxO1, FoxO3, NF-κB, HIF-1α, TFEB, and Nrf-2 enhance autophagy in the heart in I/R. Transcriptional factors STAT1, STAT3, and p53 inhibit autophagy in I/R. MicroRNAs could stimulate and inhibit autophagy in the heart in I/R. Long noncoding RNAs regulate the viability and autophagy of cardiomyocytes in hypoxia/reoxygenation (H/R). Nitric oxide (NO) donors and endogenous NO could activate autophagy of cardiomyocytes. Activation of heme oxygenase-1 promotes cardiomyocyte tolerance to H/R and enhances autophagy. Hydrogen sulfide increases cardiac tolerance to I/R and inhibits apoptosis and autophagy via mTOR and PI3-kinase activation.