Aldehyde dehydrogenase 2 protects cardiomyocytes against lipotoxicity via the AKT/glycogen synthase kinase 3 beta pathways

[Palmitic acid suppresses autophagy in neonatal rat cardiomyocytes via the cGAS-STING-IRF3 pathway]

OBJECTIVE

To investigate the effect of palmitic acid (PA) on autophagy in neonatal rat cardiomyocytes (NRCMs) and explore the underlying mechanism.

METHODS

NRCMs were isolated and cultured for 24 h before exposure to 10% BSA and 0.1, 0.3, 0.5, or 0.7 mmol/L PA for 24 h. After the treatments, the expressions of Parkin, PINK1, p62, LC3Ⅱ/ LC3Ⅰ, cGAS, STING and p-IRF3/IRF3 were detected using Western blotting and the cell viability was assessed with CCK8 assay, based on which 0.7 mmol/L was selected as the optimal concentration in subsequent experiments. The effects of cGAS knockdown mediated by cGAS siRNA in the presence of PA on autophagy-related proteins in the NRCMs were determined using Western blotting, and the expressions of P62 and LC3 in the treated cells were examined using immunofluorescence assay.

RESULTS

PA at different concentrations significantly lowered the expressions of Parkin, PINK1, LC3 Ⅱ/LC3 Ⅰ and LC3 Ⅱ/LC3 Ⅰ+Ⅱ (P < 0.05), increased the expression of p62 (P < 0.05), and inhibited the viability of NRCMs (P < 0.05). Knockdown of cGAS obviously blocked the autophagy-suppressing effect of PA and improved the viability of NRCMs (P < 0.05).

CONCLUSION

PA inhibits autophagy by activating the cGAS-STING-IRF3 pathway to reduce the viability of NRCMs.

Vaspin Mediates the Intraorgan Crosstalk Between Heart and Adipose Tissue in Lipoatrophic Mice

Lipoatrophy is characterized as selective loss of adipose tissues, leading to the severity of cardiovascular disorders. Therefore, there was close intraorgan crosstalk between adipose tissue and cardiovascular in lipoatrophy. A-ZIP/F-1 mouse, a well-established lipoatrophic model, and primary cardiomyocytes were used for investigating the pathophysiological changes and molecular mechanisms. A-ZIP/F-1 mice had severe fat loss and impaired ventricular function during growth, but closely associated with the reduction of circulating vaspin levels. Administration of recombinant vaspin protein improved cardiac structural disorders, left ventricular dysfunction, and inflammatory response in lipoatrophic mice. In detail, vaspin decreased cardiac lipid deposits, but enhanced mitochondrial biogenesis and activities. Interestingly, A-ZIP/F-1 mice transplanted with normal visceral adipose tissues exhibited improvement in cardiac structural remodeling and mitochondrial function. Mechanistically, vaspin increased cardiac AKT activity, which guaranteed the mitochondrial benefits of vaspin in lipoatrophic mice and primary mouse cardiomyocytes. The present study suggested that vaspin possessed biological benefits in attenuating lipoatrophy-induced cardiomyopathy onset, and targeting vaspin/AKT signaling was a potential strategy to maintain heart metabolism.