Zhou Zhi-Xiang, Ma Xiao-Feng, Xiong Wen-Hao, Ren Zhong, Jiang Miao, Deng Nian-Hua, Zhou Bo-Bin, Liu Hui-Ting, Zhou Kun, Hu Heng-Jing, Tang Hui-Fang, Zheng He, Jiang Zhi-Sheng
Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerosis of Hunan Province, Hengyang Medical School, University of South China, Hengyang City, Hunan Province, 421001, PR China.
Department of Cardiology, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang City, Hunan Province, 421001, PR China.
Atherosclerosis. 2024 Mar;390:117430. doi: 10.1016/j.atherosclerosis.2023.117430. Epub 2023 Dec 30.
Tripartite motif (TRIM65) is an important member of the TRIM protein family, which is a newly discovered E ligase that interacts with and ubiquitinates various substrates and is involved in diverse pathological processes. However, the function of TRIM65 in atherosclerosis remains unarticulated. In this study, we investigated the role of TRIM65 in the pathogenesis of atherosclerosis, specifically in vascular smooth muscle cells (VSMCs) phenotype transformation, which plays a crucial role in formation of atherosclerotic lesions.
Both non-atherosclerotic and atherosclerotic lesions during autopsy were collected singly or pairwise from each individual (n = 16) to investigate the relationship between TRIM65 and the development of atherosclerosis. In vivo, Western diet-fed ApoE mice overexpressing or lacking TRIM65 were used to assess the physiological function of TRIM65 on VSMCs phenotype, proliferation and atherosclerotic lesion formation. In vitro, VSMCs phenotypic transformation was induced by platelet-derived growth factor-BB (PDGF-BB). TRIM65-overexpressing or TRIM65-abrogated primary mouse aortic smooth muscle cells (MOASMCs) and human aortic smooth muscle cells (HASMCs) were used to investigate the mechanisms underlying the progression of VSMCs phenotypic transformation, proliferation and migration. Increased TRIM65 expression was detected in α-SMA-positive cells in the medial and atherosclerotic lesions of autopsy specimens. TRIM65 overexpression increased, whereas genetic knockdown of TRIM65 remarkably inhibited, atherosclerotic plaque development. Mechanistically, TRIM65 overexpression activated PI3K/Akt/mTOR signaling, resulting in the loss of the VSMCs contractile phenotype, including calponin, α-SMA, and SM22α, as well as cell proliferation and migration. However, opposite phenomena were observed when TRIM65 was deficient in vivo or in vitro. Moreover, in cultured PDGF-BB-induced TRIM65-overexpressing VSMCs, inhibition of PI3K by treatment with the inhibitor LY-294002 for 24 h markedly attenuated PI3K/Akt/mTOR activation, regained the VSMCs contractile phenotype, and blocked the progression of cell proliferation and migration.
TRIM65 overexpression enhances atherosclerosis development by promoting phenotypic transformation of VSMCs from contractile to synthetic state through activation of the PI3K/Akt/mTOR signal pathway.
三联基序（TRIM65）是TRIM蛋白家族的重要成员，是一种新发现的E3连接酶，可与多种底物相互作用并使其泛素化，参与多种病理过程。然而，TRIM65在动脉粥样硬化中的作用尚不清楚。在本研究中，我们探讨了TRIM65在动脉粥样硬化发病机制中的作用，特别是在血管平滑肌细胞（VSMC）表型转化中的作用，VSMC表型转化在动脉粥样硬化病变形成中起关键作用。
从每位个体（n = 16）单独或成对收集尸检时的非动脉粥样硬化和动脉粥样硬化病变，以研究TRIM65与动脉粥样硬化发展之间的关系。在体内，使用喂食西式饮食的过表达或缺乏TRIM65的ApoE小鼠来评估TRIM65对VSMC表型、增殖和动脉粥样硬化病变形成的生理功能。在体外，用血小板衍生生长因子-BB（PDGF-BB）诱导VSMC表型转化。使用过表达或缺失TRIM65的原代小鼠主动脉平滑肌细胞（MOASMC）和人主动脉平滑肌细胞（HASMC）来研究VSMC表型转化、增殖和迁移进展的潜在机制。在尸检标本的中膜和动脉粥样硬化病变的α-SMA阳性细胞中检测到TRIM65表达增加。TRIM65过表达增加了动脉粥样硬化斑块的形成，而TRIM65基因敲低则显著抑制了这一过程。机制上，TRIM65过表达激活了PI3K/Akt/mTOR信号通路，导致VSMC收缩表型丧失，包括钙调蛋白、α-SMA和SM22α，以及细胞增殖和迁移。然而，当TRIM65在体内或体外缺乏时，观察到相反的现象。此外，在培养的PDGF-BB诱导的过表达TRIM65的VSMC中，用抑制剂LY-294002处理24小时抑制PI3K，可显著减弱PI3K/Akt/mTOR激活，恢复VSMC收缩表型，并阻断细胞增殖和迁移的进展。
TRIM65过表达通过激活PI3K/Akt/mTOR信号通路促进VSMC从收缩状态向合成状态的表型转化，从而增强动脉粥样硬化的发展。
