Involvement of PINK1/Parkin-mediated mitophagy in AGE-induced cardiomyocyte aging

Advanced glycation end products (AGEs) can induce senescence in cardiomyocytes. However, its underlying molecular mechanisms remain unknown.

Neonatal rat cardiomyocytes were incubated with AGEs, and cellular senescence was evaluated by senescence-associated beta-galactosidase (SA-β-gal) activity and aging-associated p16 expression. In addition, mitophagic activity was evaluated by measuring the expression of the PINK1, Parkin, LC3 and p62 proteins. The mitophagy inhibitor cyclosporine A (CsA) or PINK1 siRNAs was then administered to cardiomyocytes to study the role of mitophagy in AGE-induced aging.

A significantly increased number of SA-β-gal positive cells and increased p16 protein levels were observed in cardiomyocytes treated with AGEs. Moreover, AGEs significantly increased the protein levels of PINK1 and Parkin as well as the LC3-II/LC3-I ratio, which occurred in a dose-dependent manner. However, the expression of p62 decreased significantly in the AGE group compared to the control. Surprisingly, both CsA and the knockdown of PINK1 by small-interfering RNA (siRNA) significantly decreased the LC3-II/LC3-I ratio and the PINK1 and Parkin protein levels in AGE-treated cardiomyocytes. Moreover, CsA treatment or knockdown of PINK1 expression attenuated the increased number of SA-β-gal positive cells and the upregulated p16 level in cardiomyocytes induced by AGEs.

PINK1/Parkin-mediated mitophagy is involved in the process of cardiomyocyte senescence induced by AGEs, and a reduction in mitophagic activity might be a promising approach to block the senescent state in cardiomyocytes.