MicroRNA-24-3p alleviates cardiac fibrosis by suppressing cardiac fibroblasts mitophagy via downregulating PHB2.

Cardiac fibrosis is a pathological process of multiple cardiovascular diseases, which may lead to heart failure. Studies have shown that microRNAs (miRNAs) play critical roles in regulating mitophagy and cardiac fibrosis. We found that miR-24-3p expression was significantly downregulated in transverse aortic constriction (TAC) mice and cardiac fibroblasts (CFs) treated with Ang Ⅱ. We also found that, apart from improving cardiac structure and function, forced expression of miR-24-3p not only reduced the levels of collagen and α-SMA but also inhibited proliferation and migration of CFs. Next, our research proved that miR-24-3p suppressed the progression of mitophagy, autophagic flux, and the levels of mitophagy-related proteins in cardiac fibrosis models. Further analysis showed that PHB2 was a direct target of miR-24-3p. Finally, experiments showed that the knockdown of PHB2 reversed Ang Ⅱ-induced fibrosis in CFs. The results of our study suggests that increased expression of miR-24-3p contributes to the reduction of cardiac fibrosis and that it might be targeted therapeutically to alleviate cardiac fibrosis.

The Chinese medicine Fufang Zhenzhu Tiaozhi capsule protects against atherosclerosis by suppressing EndMT via modulating Akt1/ß-catenin signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Fufang Zhenzhu Tiaozhi (FTZ) is a traditional Chinese herbal prescription that has been used to treat dyslipidemia, nonalcoholic fatty liver disease, atherosclerosis, diabetes and its complications in the clinic for almost ten years. Endothelial-mesenchymal transition (EndMT) is the key driver of atherosclerosis. However, the effects of FTZ on endothelial dysfunction and EndMT remain unknown. AIM OF THE STUDY: To evaluate the therapeutic effects of FTZ against EndMT and the underlying mechanisms. MATERIALS AND METHODS: An in vivo model of atherosclerosis was established by feeding ApoE-/- mice with a high-fat diet (HFD). The body weight, lipid levels, plaque area, lipid deposition and EndMT were evaluated using standard assays 12 weeks after intragastric administration of FTZ and simvastatin. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to simulate EndMT in vitro. The degree of EndMT was assessed after treating the cells with FTZ or transfection with si-Akt1. The expression levels of genes involved in EndMT were quantified by real-time PCR or western blotting. RESULTS: FTZ ameliorated dyslipidemia and endothelial dysfunction in the atherosclerotic mice. In addition, FTZ reduced body weight and the total cholesterol, triglycerides and low-density lipoprotein levels, and increased that of high-density lipoproteins. FTZ also upregulated the expression of endothelial markers (CD31 and VE-cadherin) and decreased that of mesenchymal markers (ɑ-SMA and FSP1), indicating that it inhibits EndMT. Knocking down Akt1 exacerbated EndMT and reversed the therapeutic effect of FTZ. CONCLUSION: FTZ delayed atherosclerosis by inhibiting EndMT via the Akt1/ß-catenin pathway.

BAG3 Alleviates Atherosclerosis by Inhibiting Endothelial-to-Mesenchymal Transition via Autophagy Activation.

Atherosclerosis is a chronic systemic inflammatory disease that causes severe cardiovascular events. B cell lymphoma 2-associated athanogene (BAG3) was proven to participate in the regulation of tumor angiogenesis, neurodegenerative diseases, and cardiac diseases, but its role in atherosclerosis remains unclear. Here, we aim to investigate the role of BAG3 in atherosclerosis and elucidate the potential molecular mechanism. In this study, ApoE-/- mice were given a tail-vein injection of BAG3-overexpressing lentivirus and fed a 12-week high-fat diet (HFD) to investigate the role of BAG3 in atherosclerosis. The overexpression of BAG3 reduced plaque areas and improved atherosclerosis in ApoE-/- mice. Our research proves that BAG3 promotes autophagy in vitro, contributing to the suppression of EndMT in human umbilical vein endothelial cells (HUVECs). Mechanically, autophagy activation is mediated by BAG3 via the interaction between BAG3 and its chaperones HSP70 and HSPB8. In conclusion, BAG3 facilitates autophagy activation via the formation of the chaperone-assisted selective autophagy (CASA) complex interacting with HSP70 and HSPB8, leading to the inhibition of EndMT during the progression of atherosclerosis and indicating that BAG3 is a potential therapeutic target for atherosclerosis.