TRIM65 promotes vascular smooth muscle cell phenotypic transformation by activating PI3K/Akt/mTOR signaling during atherogenesis

Atherosclerosis. 2024 Mar:390:117430. doi: 10.1016/j.atherosclerosis.2023.117430. Epub 2023 Dec 30.

Abstract

Background and aims: Tripartite motif (TRIM65) is an important member of the TRIM protein family, which is a newly discovered E3 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.

Methods and results: 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.

Conclusions: 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.

Keywords: ApoE(−/−) mice; Atherosclerosis; Phenotypic transformation; Signal pathway; Tripartite motif (TRIM65); VSMCs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Atherosclerosis* / pathology
  • Becaplermin / genetics
  • Becaplermin / metabolism
  • Cell Movement
  • Cell Proliferation
  • Cells, Cultured
  • Humans
  • Mice
  • Muscle, Smooth, Vascular / pathology
  • Myocytes, Smooth Muscle / pathology
  • Phenotype
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt* / metabolism
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism
  • Tripartite Motif Proteins / genetics
  • Tripartite Motif Proteins / metabolism
  • Ubiquitin-Protein Ligases / genetics

Substances

  • Becaplermin
  • Proto-Oncogene Proteins c-akt
  • Phosphatidylinositol 3-Kinases
  • TOR Serine-Threonine Kinases
  • TRIM65 protein, human
  • Tripartite Motif Proteins
  • Ubiquitin-Protein Ligases