title: CLIC1 Inhibition Attenuates Vascular Inflammation, Oxidative Stress, and Endothelial Injury.
abstract: Endothelial dysfunction, which includes endothelial oxidative damage and vascular inflammation, is a key initiating step in the pathogenesis of atherosclerosis (AS) and an independent risk factor for this disorder. Intracellular chloride channel 1 (CLIC1), a novel metamorphic protein, acts as a sensor of cell oxidation and is involved in inflammation. In this study, we hypothesize that CLIC1 plays an important role in AS. Apolipoprotein E-deficient mice were supplied with a normal diet or a high-fat and high-cholesterol diet for 8 weeks. Overexpressed CLIC1 was associated with the accelerated atherosclerotic plaque development, amplified oxidative stress, and in vivo release of inflammatory cytokines. We subsequently examined the underlying molecular mechanisms through in vitro experiments. Treatment of cultured human umbilical vein endothelial cells (HUVECs) with H2O2 induced endothelial oxidative damage and enhanced CLIC1 expression. Suppressing CLIC1 expression through gene knocked-out (CLIC1-/-) or using the specific inhibitor indanyloxyacetic acid-94 (IAA94) reduced ROS production, increased SOD enzyme activity, and significantly decreased MDA level. CLIC1-/- HUVECs exhibited significantly reduced expression of TNF-α and IL-1β as well as ICAM-1 and VCAM-1 at the protein levels. In addition, H2O2 promoted CLIC1 translocation to the cell membrane and insertion into lipid membranes, whereas IAA94 inhibited CLIC1 membrane translocation induced by H2O2. By contrast, the majority of CLIC1 did not aggregate on the cell membrane in normal HUVECs, and this finding is consistent with the changes in cytoplasmic chloride ion concentration. This study demonstrates for the first time that CLIC1 is overexpressed during AS development both in vitro and in vivo and can regulate the accumulation of inflammatory cytokines and production of oxidative stress. Our results also highlight that deregulation of endothelial functions may be associated with the membrane translocation of CLIC1 and active chloride-selective ion channels in endothelial cells.
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Yingling
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Clinical Laboratory, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Zhu
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Hu
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Dezhao
authors.initials: D
authors.lastname: Lu
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Chenxue
authors.initials: C
authors.lastname: Gong
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Jinhuan
authors.initials: J
authors.lastname: Yang
authors.affiliation: College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zong
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency; D050197:Atherosclerosis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers; D002448:Cell Adhesion; D018118:Chloride Channels / Q000235:genetics* / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress / Q000235:genetics*; D058226:Plaque, Atherosclerotic; D021381:Protein Transport; D017382:Reactive Oxygen Species / Q000378:metabolism; D014657:Vasculitis / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology
chemical_list: D001057:Apolipoproteins E; D015415:Biomarkers; D018118:Chloride Channels; C501967:Clic1 protein, mouse; D016207:Cytokines; D018836:Inflammation Mediators; D017382:Reactive Oxygen Species