title: Involvement of RAGE, NADPH oxidase, and Ras/Raf-1 pathway in glycated LDL-induced expression of heat shock factor-1 and plasminogen activator inhibitor-1 in vascular endothelial cells.
abstract: Atherothrombotic cardiovascular diseases are the predominant causes of mortality of diabetic patients. Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor for fibrinolysis, and it is also implicated in inflammation and tissue remodeling. Increased levels of PAI-1 and glycated low-density lipoprotein (glyLDL) were detected in patients with diabetes. Previous studies in our laboratory demonstrated that heat shock factor-1 (HSF1) is involved in glyLDL-induced PAI-1 overproduction in vascular endothelial cells (EC). The present study investigated transmembrane signaling mechanisms involved in glyLDL-induced HSF1 and PAI-1 up-regulation in cultured human vascular EC and streptozotocin-induced diabetic mice. Receptor for advanced glycation end products (RAGE) antibody prevented glyLDL-induced increase in the abundance of PAI-1 in EC. GlyLDL significantly increased the translocation of V-Ha-Ras Harvey rat sarcoma viral oncogene homologue (H-Ras) from cytoplasm to membrane compared with LDL. Farnesyltransferase inhibitor-277 or small interference RNA against H-Ras inhibited glyLDL-induced increases in HSF1 and PAI-1 in EC. Treatment with diphenyleneiodonium, a nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor, blocked glyLDL-induced translocation of H-Ras, elevated abundances of HSF1 and PAI-1 in EC, and increased release of hydrogen peroxide from EC. Small interference RNA for p22(phox) prevented glyLDL-induced expression of NOX2, HSF1, and PAI-1 in EC. GlyLDL significantly increased V-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) phosphorylation. Treatment with Raf-1 inhibitor blocked glyLDL-induced increase of PAI-1 mRNA in EC. The levels of RAGE, H-Ras, NOX4, HSF1, and PAI-1 were increased in hearts of streptozotocin-diabetic mice and positively correlated with plasma glucose. The results suggest that RAGE, NOX, and H-Ras/Raf-1 are implicated in the up-regulation of HSF1 or PAI-1 in vascular EC under diabetes-associated metabolic stress.
authors.affiliation: Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada R3E 3P4.
authors.forename: Ganesh V
authors.initials: GV
authors.lastname: Sangle
authors.forename: Ruozhi
authors.initials: R
authors.lastname: Zhao
authors.forename: Tooru M
authors.initials: TM
authors.lastname: Mizuno
authors.forename: Garry X
authors.initials: GX
authors.lastname: Shen
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000139:chemically induced / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017127:Glycation End Products, Advanced; D000076249:Heat Shock Transcription Factors; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D034622:RNA Interference; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D013311:Streptozocin; D014157:Transcription Factors / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism; D000093844:Glycated Proteins
chemical_list: D000906:Antibodies; D001786:Blood Glucose; D004268:DNA-Binding Proteins; D017127:Glycation End Products, Advanced; D000076249:Heat Shock Transcription Factors; D008077:Lipoproteins, LDL; D019255:NADPH Oxidases; D009861:Onium Compounds; D017395:Plasminogen Activator Inhibitor 1; D019908:Proto-Oncogene Proteins c-raf; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D013311:Streptozocin; D014157:Transcription Factors; D018631:ras Proteins; C000619706:HSF1 protein, human; C000619709:Hsf1 protein, rat; C031797:glycated lipoproteins, LDL; D000093844:Glycated Proteins; C007517:diphenyleneiodonium; C086986:CYBA protein, human