Myocardin suppression increases lipid retention and atherosclerosis via downregulation of ABCA1 in vascular smooth muscle cells.

Abstract

Myocardin (MYOCD) plays an important role in cardiovascular disease. However, its underlying impact on atherosclerosis remains to be elucidated. ATP binding cassette transporter A1 (ABCA1), a key membrane-associated lipid transporter which maintains intracellular lipid homeostasis, has a protective function in atherosclerosis progress. The purpose of this study was to investigate whether and how the effect of MYOCD on atherosclerosis is associated with ABCA1 in vascular smooth muscle cells (VSMCs). We found both MYOCD and ABCA1 expression were dramatically decreased in atherosclerotic patient aortas compared to control. MYOCD knockdown inhibited ABCA1 expression in human aortic vascular smooth muscle cells (HAVSMCs), leading to reduced cholesterol efflux and increased intracellular cholesterol contents. MYOCD overexpression exerted the opposite effect. Mechanistically, MYOCD regulates ABCA1 expression in an SRF-dependent manner. Consistently, apolipoprotein E-deficient mice treated with MYOCD shRNA developed more plaques in the aortic sinus, which is associated with reduced ABCA1 expression, increased cholesterol retention in the aorta, and decreased high-density lipoprotein cholesterol levels in the plasma. Our data suggest that MYOCD deficiency exacerbates atherosclerosis by downregulating ABCA1 dependent cholesterol efflux from VSMCs, thereby providing a novel strategy for the therapeutic treatment of atherosclerotic cardiovascular disease.

• Authors: Xiao-Dan Xia, Xiao-Hua Yu, Ling-Yan Chen, Song-Lin Xie, Yao-Guang Feng, Rui-Zhe Yang, Zhen-Wang Zhao, Heng Li, Gang Wang, Chao-Ke Tang
• Journal: Biochimica et biophysica acta. Molecular and cell biology of lipids (Biochim Biophys Acta Mol Cell Biol Lipids) Vol. 1866 Issue 4 Pg. 158824 (04 2021) ISSN: 1879-2618 [Electronic] Netherlands
• PMID: 33035679 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2020. Published by Elsevier B.V.

Chemical References

• ABCA1 protein, human
• ABCA1 protein, mouse
• ATP Binding Cassette Transporter 1
• Nuclear Proteins
• Trans-Activators
• myocardin

Topics

• ATP Binding Cassette Transporter 1 (genetics, metabolism)
• Aged
• Aged, 80 and over
• Animals
• Aorta (cytology, metabolism, pathology)
• Atherosclerosis (genetics, metabolism, pathology)
• Cells, Cultured
• Down-Regulation
• Female
• Humans
• Lipid Metabolism
• Male
• Mice, Knockout, ApoE
• Middle Aged
• Muscle, Smooth, Vascular (cytology, metabolism, pathology)
• Nuclear Proteins (genetics, metabolism)
• Trans-Activators (genetics, metabolism)
• Mice