Sirtuin 7 ameliorates cuproptosis, myocardial remodeling and heart dysfunction in hypertension through the modulation of YAP/ATP7A signaling

Abstract

Myocardial fibrosis is a typical pathological manifestation of hypertension. However, the exact role of sirtuin 7 (SIRT7) in myocardial remodeling remains largely unclear. Here, spontaneously hypertensive rats (SHRs) and angiotensin (Ang) II-induced hypertensive mice were pretreated with recombinant adeno-associated virus (rAAV)-SIRT7, copper chelator tetrathiomolybdate (TTM) or copper ionophore elesclomol, respectively. Compared with normotensive controls, reduced SIRT7 expression and augmented cuproptosis were observed in hearts of hypertensive rats and mice with decreased FDX1 levels and increased HSP70 levels. Notably, intervention with rAAV-SIRT7 and TTM strikingly prevented DLAT oligomers aggregation, and elevated ATP7A and TOM20 expressions, contributing to the alleviation of cuproptosis, mitochondrial injury, myocardial remodeling and heart dysfunction in spontaneously hypertensive rats and Ang II-induced hypertensive mice. In cultured rat primary cardiac fibroblasts (CFs), rhSIRT7 alleviated CuCl₂, Ang II or elesclomol-induced cuproptosis and fibroblast activation by blunting DLAT oligomers accumulation and downregulating α-SMA expression. Additionally, conditioned medium from rhSIRT7-pretreated CFs remarkably mitigated cellular hypertrophy and mitochondrial impairments of neonatal rat cardiomyocytes, as well as cell migration and polarization of RAW 264.7 macrophages. Importantly, verteporfin reduced CuCl₂-induced cuproptosis, mitochondrial injury and fibrotic activation in CFs. Knockdown of ATP7A with si-ATP7A blocked cellular protective effects of rhSIRT7 and verteporfin in CFs. In conclusion, SIRT7 attenuates cuproptosis, myocardial fibrosis and heart dysfunction in hypertension through the modulation of YAP/ATP7A signaling. Targeting SIRT7 is of vital importance for developing therapeutic strategies in hypertension and hypertensive heart disorders.