WTAP Silencing protects human aortic smooth muscle cells from angiotensin II-induced senescence, apoptosis, ferroptosis, and inflammation by regulating PCSK9.

Abstract

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease characterized by aortic wall degeneration and inflammation. The molecular mechanisms underlying AAA development remain unclear. Wilms tumor 1-associated protein (WTAP) has been implicated in various biological processes, but its role in AAA pathogenesis, particularly in cardiomyocyte regulation, has not been fully explored. Quantitative real-time PCR (qRT-PCR) was performed to detect the mRNA levels of WTAP and proprotein convertase subtilisin/kexin type 9 (PCSK9). Western blotting assay was used to analyze protein expression. Cell viability, proliferation, senescence, apoptosis, ferroptosis, and inflammation were assessed using cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay, SA-β-gal staining, flow cytometry, fluorometric assay, colorimetric method, and enzyme-linked immunosorbent assay. The association among PCSK9, WTAP, and IGF2BP2 was analyzed using RNA immunoprecipitation assay and dual-luciferase reporter assay. WTAP expression was upregulated in AAA and angiotensin II (Ang II)-induced human aortic smooth muscle cells (HASMCs). Ang II treatment inhibited HASMC proliferation and induced senescence, apoptosis, ferroptosis, and NLRP3 inflammasome-mediated inflammation. However, these effects were mitigated by WTAP knockdown. In addition, PCSK9 expression was increased in AAA, and WTAP stabilized PCSK9 mRNA expression in an IGF2BP2-dependent manner. Moreover, WTAP overexpression promoted senescence, apoptosis, ferroptosis, and inflammation by regulating PCSK9 in Ang II-induced HASMCs. WTAP silencing protected HASMCs from Ang II-induced senescence, apoptosis, ferroptosis, and inflammation by regulating PCSK9, suggesting a potential therapeutic target for AAA treatment.