ROS-mediated downregulation of MYPT1 in smooth muscle cells: a potential mechanism for the aberrant contractility in atherosclerosis
| Autor: | Meei Jyh Jiang, Jung-Chien Cheng, I-Ching Tsai, Hui-Pin Cheng |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
medicine.medical_specialty
Smooth muscle cell migration Myocytes Smooth Muscle Down-Regulation Pathology and Forensic Medicine Contractility Mice Myosin-Light-Chain Phosphatase Downregulation and upregulation Cell Movement Peroxynitrous Acid Stress Fibers Internal medicine Myosin medicine Animals Humans Myocyte RNA Messenger Molecular Biology Aorta Cells Cultured Mice Knockout Platelet-Derived Growth Factor chemistry.chemical_classification Reactive oxygen species NADPH oxidase biology Superoxide Dismutase Hydrogen Peroxide Cell Biology Atherosclerosis Actin cytoskeleton Cell biology Mice Inbred C57BL Endocrinology chemistry Gene Knockdown Techniques biology.protein Female Reactive Oxygen Species |
| Zdroj: | Laboratory Investigation. 93:422-433 |
| ISSN: | 0023-6837 |
| DOI: | 10.1038/labinvest.2013.40 |
| Popis: | Reactive oxygen species (ROS) mediates the aberrant contractility in hypertension. Abnormal contractility occurs in atherosclerotic vessels but changes in proteins that regulate contractility remain poorly understood. Myosin phosphatase (MP) activity, which regulates smooth muscle relaxation, is regulated by the phosphorylation of its regulatory subunit, MP targeting subunit 1 (MYPT1). In the present study, we examined the roles of ROS in MP subunit expression both in cultured human aortic smooth muscle cells (HASMCs) and during atherosclerosis progression in apolipoprotein E-knockout (apoE-KO) mice. Furthermore, the effect of decreased MYPT1 on actin cytoskeleton and cell migration activity was assessed in HASMCs. Short hairpin RNA-mediated knockdown of MYPT1 increased stress fibers and attenuated platelet-derived growth factor-induced cell migration in HASMCs. Superoxide anion-inducing agent LY83583 downregulated MYPT1 mRNA and protein levels, but did not affect the phosphorylation of MYPT1 and catalytic subunit of MP, PP1δ. The LY83583-induced decrease in MYPT1 was abolished by co-treating with superoxide dismutase or by inhibiting NADPH oxidase with diphenyleneiodonium. Treatment of peroxynitrite, but not hydrogen peroxide (H2O2), downregulated MYPT1 protein expression and induced MYPT1 phosphorylation without affecting mRNA levels. Co-treatment with a proteasome inhibitor, MG-132, eliminated peroxynitrite-induced MYPT1 downregulation. In apoE-KO mice, MYPT1 protein, but not mRNA, levels were markedly decreased in 16-week- and 24-week-old mice. Oral estrogen treatment, which was previously shown to decrease aortic ROS levels, upregulated aortic MYPT1 expression. Moreover, reduction in MYPT1 expression correlated with increased aortic sensitivity toward vasoconstrictors. These results suggested that during atherosclerosis progression oxidative stress mediates the downregulation of MYPT1, which may inhibit smooth muscle cell migration and contribute to the aberrant contractility. |
| Databáze: | OpenAIRE |
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