title: NOX4-derived reactive oxygen species limit fibrosis and inhibit proliferation of vascular smooth muscle cells in diabetic atherosclerosis.
abstract: Smooth muscle cell (SMC) proliferation and fibrosis contribute to the development of advanced atherosclerotic lesions. Oxidative stress caused by increased production or unphysiological location of reactive oxygen species (ROS) is a known major pathomechanism. However, in atherosclerosis, in particular under hyperglycaemic/diabetic conditions, the hydrogen peroxide-producing NADPH oxidase type 4 (NOX4) is protective. Here we aim to elucidate the mechanisms underlying this paradoxical atheroprotection of vascular smooth muscle NOX4 under conditions of normo- and hyperglycaemia both in vivo and ex vivo. Following 20-weeks of streptozotocin-induced diabetes, Apoe(-/-) mice showed a reduction in SM-alpha-actin and calponin gene expression with concomitant increases in platelet-derived growth factor (PDGF), osteopontin (OPN) and the extracellular matrix (ECM) protein fibronectin when compared to non-diabetic controls. Genetic deletion of Nox4 (Nox4(-/)(-)Apoe(-/-)) exacerbated diabetes-induced expression of PDGF, OPN, collagen I, and proliferation marker Ki67. Aortic SMCs isolated from NOX4-deficient mice exhibited a dedifferentiated phenotype including loss of contractile gene expression, increased proliferation and ECM production as well as elevated levels of NOX1-associated ROS. Mechanistic studies revealed that elevated PDGF signalling in NOX4-deficient SMCs mediated the loss of calponin and increase in fibronectin, while the upregulation of NOX1 was associated with the increased expression of OPN and markers of proliferation. These findings demonstrate that NOX4 actively regulates SMC pathophysiological responses in diabetic Apoe(-/-) mice and in primary mouse SMCs through the activities of PDGF and NOX1.
authors.affiliation: Diabetic Complications Division, Baker IDI Heart & Diabetes Institute, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia.
authors.forename: Elyse
authors.initials: E
authors.lastname: Di Marco
authors.affiliation: Diabetic Complications Division, Baker IDI Heart & Diabetes Institute, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Gray
authors.affiliation: Diabetic Complications Division, Baker IDI Heart & Diabetes Institute, Melbourne, Australia.
authors.forename: Kit
authors.initials: K
authors.lastname: Kennedy
authors.affiliation: Genkyotex SA, Geneva, Switzerland.
authors.forename: Cedric
authors.initials: C
authors.lastname: Szyndralewiez
authors.affiliation: Division of Cardiology, Department of Medicine, Emory University, Atlanta, USA.
authors.forename: Alicia N
authors.initials: AN
authors.lastname: Lyle
authors.affiliation: Division of Cardiology, Department of Medicine, Emory University, Atlanta, USA.
authors.forename: Bernard
authors.initials: B
authors.lastname: Lassègue
authors.affiliation: Division of Cardiology, Department of Medicine, Emory University, Atlanta, USA.
authors.forename: Kathy K
authors.initials: KK
authors.lastname: Griendling
authors.affiliation: Diabetic Complications Division, Baker IDI Heart & Diabetes Institute, Melbourne, Australia.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Cooper
authors.affiliation: Department of Pharmacology & Cardiovascular Research Institute Maastricht (CARIM), Faculty of Medicine, Health & Life Science, Maastricht University, The Netherlands.
authors.forename: Harald H H W
authors.initials: HHHW
authors.lastname: Schmidt
authors.affiliation: Diabetic Complications Division, Baker IDI Heart & Diabetes Institute, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia. Electronic address: Karin.jandeleit-dahm@bakeridi.edu.au.
authors.forename: Karin A M
authors.initials: KAM
authors.lastname: Jandeleit-Dahm
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D050197:Atherosclerosis / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D000077214:Becaplermin; D049109:Cell Proliferation; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000201:enzymology* / Q000473:pathology; D005355:Fibrosis; D008297:Male; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D000074624:NADPH Oxidase 1 / Q000378:metabolism; D000074663:NADPH Oxidase 4 / Q000235:genetics / Q000378:metabolism*; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D020574:Proto-Oncogene Proteins c-sis; D017382:Reactive Oxygen Species; D053495:Osteopontin; D013481:Superoxides; D000077214:Becaplermin; D000074624:NADPH Oxidase 1; D000074663:NADPH Oxidase 4; C000614711:NOX1 protein, mouse; C422943:Nox4 protein, mouse
keywords: Atherosclerosis; Diabetes; NOX4; Vascular smooth muscle cell