CYLD Deubiquitinates Nicotinamide Adenine Dinucleotide Phosphate Oxidase 4 Contributing to Adventitial Remodeling.

Transdifferentiation of adventitial fibroblasts (AFs) into myofibroblasts plays a critical role during the vascular remodeling that occurs during atherosclerosis, restenosis, and aortic aneurysm. The ubiquitination/deubiquitination regulatory system is essential for the quality control of proteins. The involvement of ubiquitination/deubiquitination during AF transdifferentiation remains largely unknown. In this study, we determined ...
the role of cylindromatosis (CYLD), a deubiquitinase, in the process of AF differentiation and activation in vitro and in vivo.Transforming growth factor-β1 and homocysteine, 2 known inducers of AF transdifferentiation, greatly upregulated CYLD expression in a time- and dose-dependent manner. The silencing of CYLD significantly inhibited AF transdifferentiation and activation as evidenced by the expression of contractile proteins, the production of the proinflammatory cytokines MCP-1 (monocyte chemotactic protein 1) and IL-6 (interleukin-6), the deposition of extracellular matrix, and cell migration. We further asked whether CYLD mediates AF activation via the regulation of nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) as it is an essential factor during AF transdifferentiation. Indeed, the silencing of CYLD repressed transforming growth factor-β1-induced and homocysteine-induced Nox4 upregulation and reactive oxygen species production, whereas Nox4 overexpression greatly rescued the inhibitory effect on AF activation by CYLD silencing. Most interestingly, transforming growth factor-β1 and homocysteine repressed Nox4 ubiquitination and prolonged the half-life of Nox4. Moreover, Nox4 was deubiquitinated via a direct interaction with the ubiquitin-specific protease domain of CYLD. In accordance, hyperhomocysteinemia significantly increased adventitial CYLD and Nox4 expression, promoted AF transdifferentiation, and aggravated CaPO4-induced abdominal aortic aneurysm in mice. These effects were abolished in CYLD-/- mice.CYLD contributes to the transdifferentiation of AFs via deubiquitinating Nox4 and may play a role in vascular remodeling.
Mesh Terms:
Adventitia, Animals, Aortic Aneurysm, Abdominal, COS Cells, Calcium Phosphates, Cell Movement, Cell Transdifferentiation, Cercopithecus aethiops, Chemokine CCL2, Cysteine Endopeptidases, Disease Models, Animal, Dose-Response Relationship, Drug, Enzyme Stability, Extracellular Matrix, Genotype, HEK293 Cells, Half-Life, Homocysteine, Humans, Hyperhomocysteinemia, Interleukin-6, Male, Mice, Inbred C57BL, Mice, Knockout, Myofibroblasts, NADPH Oxidase 4, NADPH Oxidases, Phenotype, Proteolysis, RNA Interference, Rats, Sprague-Dawley, Reactive Oxygen Species, Signal Transduction, Time Factors, Transfection, Transforming Growth Factor beta1, Ubiquitin Thiolesterase, Ubiquitination, Vascular Remodeling
Arterioscler. Thromb. Vasc. Biol.
Date: Dec. 01, 2016
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