Transient Receptor Potential Vanilloid Type 1 Protects Against Pressure Overload-Induced Cardiac Hypertrophy by Promoting Mitochondria-Associated Endoplasmic Reticulum Membranes

Transient receptor potential vanilloid type 1 (TRPV1) is a nonselective cation channel that mediates the relationship between mitochondrial function and pathological myocardial hypertrophy. However, its underlying mechanisms remain unclear. This study aimed to investigate whether TRPV1 activation improves the morphology and function of intracellular mitochondria to protect cardiomyocytes after pressure overload-induced myocardial hypertrophy. The myocardial hypertrophy model was established by performing transverse aortic constriction surgery in C57BL/6 J male mice. The data revealed that TRPV1 activation significantly reduced myocardial hypertrophy, promoted ejection fraction% and fractional shortening%, and decreased the left ventricular internal diameter in end-diastole and left ventricular internal diameter in end-systole after transverse aortic constriction. Moreover, in vitro experiments revealed that TRPV1 reduces cardiomyocyte area and improves mitochondrial function by promoting mitochondria-associated endoplasmic reticulum membranes (MAMs) formation in a phenylephrine-treated cardiomyocyte hypertrophy model. TRPV1 up-regulates the phosphorylation levels of AMP-activated protein kinase and expression of mitofusin2 (MFN2). TRPV1 function is blocked by single-stranded RNA interfering with silent interfering MFN2. Activation of TRPV1 reduced mitochondrial Reactive Oxygen Species caused by phenylephrine, whereas disruption of MAMs by siMFN2 abolished TRPV1-mediated mitochondrial protection. Our findings suggest that TRPV1 effectively protects against pressure overload-induced cardiac hypertrophy by promoting MAM formation and conserved mitochondrial function via the AMP-activated protein kinase/MFN2 pathway in cardiomyocytes.