title: Regulatory role of NADPH oxidase in glycated LDL-induced upregulation of plasminogen activator inhibitor-1 and heat shock factor-1 in mouse embryo fibroblasts and diabetic mice.
abstract: Cardiovascular disease is the predominant cause of death in diabetic patients. Fibroblasts are one of the major types of cells in the heart or vascular wall. Increased levels of glycated low-density lipoprotein (glyLDL) were detected in diabetic patients. Previous studies in our group demonstrated that oxidized LDL increased the amounts of NADPH oxidase (NOX), plasminogen activator inhibitor-1 (PAI-1), and heat shock factor-1 (HSF1) in fibroblasts. This study examined the expression of NOX, PAI-1, and HSF1 in glyLDL-treated wild-type or HSF1-deficient mouse embryo fibroblasts (MEFs) and in leptin receptor-knockout (db/db) diabetic mice. Treatment with physiologically relevant levels of glyLDL increased superoxide and H2O2 release and the levels of NOX4 and p22phox (an essential component of multiple NOX complexes) in wild-type or HSF1-deficient MEFs. The levels of HSF1 and PAI-1 were increased by glyLDL in wild-type MEFs, but not in HSF1-deficient MEFs. Diphenyleneiodonium (a nonspecific NOX inhibitor) or small interfering RNA for p22phox prevented glyLDL-induced increases in the levels of NOX4, HSF1, or PAI-1 in MEFs. The amounts of NOX4, HSF1, and PAI-1 were elevated in hearts of db/db diabetic mice compared to wild-type mice. The results suggest that glyLDL increased the abundance of NOX4 or p22phox via an HSF1-independent pathway, but that of PAI-1 via an HSF1-dependent manner. NOX4 plays a crucial role in glyLDL-induced expression of HSF1 and PAI-1 in mouse fibroblasts. Increased expression of NOX4, HSF1, and PAI-1 was detected in cardiovascular tissue of diabetic mice.
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada MB R3E 3P4.
authors.forename: Ruozhi
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada MB R3E 3P4.
authors.forename: Khuong
authors.initials: K
authors.lastname: Le
authors.affiliation: Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada MB R3E 3P4.
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Moghadasian
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada MB R3E 3P4. Electronic address: gshen@ms.umanitoba.ca.
authors.forename: Garry X
authors.initials: GX
authors.lastname: Shen
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003573:Cytochrome b Group / Q000032:analysis / Q000502:physiology; D004268:DNA-Binding Proteins / Q000032:analysis / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D017127:Glycation End Products, Advanced; D000076249:Heat Shock Transcription Factors; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D054411:Receptors, Leptin / Q000172:deficiency; D014157:Transcription Factors / Q000032:analysis / Q000502:physiology*; D015854:Up-Regulation; D000093844:Glycated Proteins
chemical_list: D003573:Cytochrome b Group; D004268:DNA-Binding Proteins; D017127:Glycation End Products, Advanced; D000076249:Heat Shock Transcription Factors; D008077:Lipoproteins, LDL; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; D017395:Plasminogen Activator Inhibitor 1; D017382:Reactive Oxygen Species; D054411:Receptors, Leptin; D014157:Transcription Factors; C490017:Hsf1 protein, mouse; C031797:glycated lipoproteins, LDL; D000093844:Glycated Proteins; C515447:leptin receptor, mouse; C422943:Nox4 protein, mouse; C515614:Cyba protein, mouse
keywords: Free radicals; Glycated low-density lipoprotein; Heat shock factor-1; Leptin receptor-knockout diabetic mice; Mouse embryo fibroblasts; NADPH oxidase; Plasminogen activator inhibitor-1