ALKBH5 Regulates Inflammation and Pyroptosis of Coronary Heart Disease by Targeting SPEN in a YTHDF1-Mediated Manner.

Abstract

PURPOSE: Coronary heart disease (CHD) occurs when the arteries supplying blood to the heart become narrowed or blocked owing to plaque buildup, leading to reduced blood flow and potential heart attacks. N6-methyladenosine (mA) modification is a common form of post-transcriptional RNA modification. ALKB homolog 5 (ALKBH5) is an RNA demethylase that specifically removes the mA modification from RNA. This study aimed to investigate the role of ALKBH5 in CHD and the underlying mechanism. METHODS: Both cellular and animal CHD models were established. The expression levels of Alkbh5 and fibrosis-related markers were analyzed by qRT-PCR. Cell viability and cytotoxicity were assessed via cell counting kit-8. Inflammatory cytokines levels were detected by ELISA. Flow cytometry was used to detect pyroptosis. The interaction between ALKBH5/YTH N6-methyladenosine RNA binding protein (YTHDF)1 and SPEN transcriptional repressor (SPEN) was examined through RNA immunoprecipitation and dual-luciferase reporter assays. RESULTS: ALKBH5-mediated demethylation of mA was decreased in CHD rat heart tissues and oxidized low-density lipoprotein (ox-LDL)-treated H9c2 cells. In addition, Alkbh5 overexpression increased the cell viability and suppressed the inflammation, pyroptosis, and fibrosis in ox-LDL-treated H9c2 cells. In in vivo studies, Alkbh5 overexpression reduced myocardial injury and fibrosis in CHD rats by suppressing inflammation and pyroptosis. Mechanically, Alkbh5 overexpression decreased the stability of Spen mRNA. Additionally, ALKBH5/YTHDF1 mA axis regulated the expression of Spen. Moreover, Ythdf1 overexpression counteracted ALKBH5-mediated inhibition of inflammation, pyroptosis, and fibrosis in ox-LDL-treated H9c2 cells. CONCLUSION: ALKBH5 regulated inflammation and pyroptosis of CHD by targeting SPEN in a YTHDF1-mediated manner, which could provide a reference for CHD treatment.