Salvianic acid A ameliorates atherosclerosis through metabolic-dependent anti-EndMT pathway and repression of TGF-β/ALK5 signaling

Abstract

Background

Endothelial-to-mesenchymal transition (EndMT) has been identified as a key factor to the initiation and progression of the pathogenesis of atherosclerosis (AS). Salvianic acid A (SAAS) is the primary water-soluble bioactive ingredient found in Salvia miltiorrhiza, is renowned for its therapeutic effects on cardiovascular diseases. However, the efficacy and mechanisms of SAAS in treating EndMT-induced AS remain underexplored.

Purpose

This study aimed to investigate the role SAAS in reversing EndMT process to impede AS development.

Methods

We used a murine model of cholesterol-rich and high-fat diet-induced AS in ApoE^-/- mice to evaluate the effect of SAAS on EndMT during AS progression in vivo. The biological effects of SAAS on EndMT-induced HUVEC cells were also detected by transcriptome sequencing (RNA-seq). Mechanistic exploration was carried out using omics data mining and screening, gene knockout experiments, gene expression, protein expression, and localization of key gene expression in animal lesion areas.

Results

We found that SAAS treatment significantly alleviated EndMT injury in the AS mice model and also improved aortic root lesions and dyslipidemia. Furthermore, pre-treatment with SAAS effectively inhibited the EndMT in HUVEC cells, as evidenced by maintained endothelial cell morphology and reduced cell migration ability, as well as elevated CD31 and decreased α-SMA. RNA sequencing data indicated that key differentially expressed genes were mainly enriched in metabolism-related and TGF-β receptor signaling pathways. The metabolic regulator PDK4 and profibrotic TGF-β receptor ALK5 were identified specifically. Subsequently, RT-qPCR and western blot results demonstrated that SAAS notably increased metabolic regulator PDK4 and decreased profibrotic TGF-β receptor ALK5 in EndMT-induced HUVEC cells. Moreover, siRNA-directed PDK4 inhibition resulted in EndMT induction and SAAS mediated the suppression of EndMT in a PDK4-dependent manner. Additionally, SAAS partially reduced the TGF-β receptor ALK5 expression. Furthermore, ApoE^-/- AS mice with SAAS treatment displayed downregulation of ALK5 and upregulation of PDK4 with reduced EndMT during AS.

Conclusion

This investigation demonstrated that SAAS improved AS through metabolic-dependent anti-EndMT pathway and repression of profibrotic TGF-β receptor signaling, thereby providing SAAS as a promising therapeutic candidate for managing AS and EndMT-related disorders.