EZH2 Regulates ANXA6 Expression via H3K27me3 and Is Involved in Angiotensin II-Induced Vascular Smooth Muscle Cell Senescence

Abstract

Objectives. Abdominal aortic aneurysm (AAA) has a high risk of rupture of the aorta and is one of the leading causes of death in older adults. This study is aimed at confirming the influence and mechanism of the abnormally expressed ANXA6 gene in AAA. Methods. Clinical samples were collected for proteome sequencing to screen for differentially expressed proteins. An Ang II-induced vascular smooth muscle cell (VSMC) aging model as well as an AAA animal model was used. Using RT-qPCR to detect the mRNA levels of EZH2, ANXA6, IK-6, and IL-8 in cells and tissues were assessed. Western blotting and immunohistochemistry staining were used apply for the expression of associated proteins in cells and tissues. SA-β-gal staining, flow cytometry, and DHE staining were used to detect senescent cells and the level of ROS. The cell cycle was assessed by flow cytometry. Arterial pathology was observed by HE staining. The aging of VSMCs in arterial tissue was assessed by coimmunofluorescence for α-SMA and p53. Results. There were 24 differentially expressed proteins in the AAA clinical samples, including 10 upregulated protein and 14 downregulated protein, and the differential expression of ANXA6 was associated with vascular disease. Our study found that ANXA6 was highly expressed and EZH2 was lowly expressed in an Ang II-induced VSMC aging model. Knockdown of ANXA6 or overexpression of EZH2 inhibited Ang II-induced ROS, inhibited cell senescence, decreased Ang II evoked G1 arrest, and increased cells in G2 phase, while overexpression of ANXA6 played the opposite role. Overexpression of EZH2 inhibited ANXA6 expression by increasing H3K27me3 modification at the ANXA6 promoter. Simultaneous overexpression of EZH2 and the protective effect of EZH2 on cell senescence were partially reversed by ANXA6. Similarly, ANXA6 was highly expressed and EZH2 was lowly expressed in an Ang II-induced AAA animal model. Knockdown of ANXA6 and overexpression of EZH2 alleviated Ang II-induced VSMC senescence and inhibited AAA progression, while simultaneous overexpression of EZH2 and ANXA6 partially reversed the protective effect of EZH2 on AAA. Conclusion. EZH2 regulates the ANXA6 promoter H3K27me3 modification, inhibits ANXA6 expression, alleviates Ang II-induced VSMC senescence, and inhibits AAA progression.

ANXA6: a key molecular player in cancer progression and drug resistance

“…ANXA6 overexpression has the opposite effect. EZH2 regulates ANXA6 promoter H3K27me3 modification, inhibits ANXA6 expression, attenuates Ang II-induced senescence in blood smooth muscle cells, and inhibits the progression of an abdominal aortic aneurysm (AMA) [ 107 ].…”

Enhancer of zeste homolog 2 facilitates phenotypic transition of vascular smooth muscle cells leading to aortic aneurysm/dissection

“…Wang et al ( 19 ) demonstrated that EZH2 expression increases the migration of pulmonary arterial smooth muscle cells (SMCs) and participates in the pathogenesis of pulmonary arterial hypertension. EZH2 enhances apoptosis in SMCs and the formation of abdominal aortic aneurysms ( 20 ). However, the biological effects of EZH2, as well as the association between EZH2 and TAA, remain unclear.…”

Role of EZH2-mediated epigenetic modification on vascular smooth muscle in cardiovascular diseases: A mini-review

“…Enhancer of zeste homolog 2 (EZH2) is a methyltransferase from the Polycomb gene family, significantly impacting VSMC proliferation and differentiation. EZH2 regulates these processes by modifying histone methylation on microRNAs and the N-terminal tail of the 27th amino acid, lysine, on core histone H3 (H3K27me3) ( Zhang et al, 2021 ; Li et al, 2022 ; Zhong et al, 2022 ). Furthermore, EZH2 influences VSMC contraction and relaxation by modulating the expression of critical genes such as those encoding calcium channels and actin.…”