title: Enhanced expression of osteopontin by high glucose. Involvement of osteopontin in diabetic macroangiopathy.
abstract: Atherosclerotic vascular disease is a major complication of diabetic patients. Osteopontin has recently been implicated in the development of atherosclerosis. In the present study, we have investigated the effects of high glucose on expression of osteopontin in cultured rat aortic smooth muscle cells. High concentrations of glucose increased osteopontin secretion from the cells, and the increased secretion was completely inhibited by an inhibitor of protein kinase C, GF109203X. Northern blot analysis confirmed the enhanced effect of glucose on expression of osteopontin mRNA. Promoter activity of osteopontin, measured using the osteopontin promoter/luciferase expression vector system, was increased by high glucose, and the enhanced effect was completely inhibited by GF109203X. Glucosamine also increased the promoter activity of osteopontin. Azaserine, an inhibitor of glutamine:fructose-6-phosphate amidotransferase, the key enzyme of the hexosamine pathway, profoundly inhibited high glucose-mediated increase in the promoter activity. Taken together, these data indicate that high glucose enhances the expression of osteopontin at the transcriptional level possibly through the activation of protein kinase C as well as the hexosamine pathway. Our results suggest that osteopontin could play a role in the development of diabetic vascular complications.
authors.affiliation: Second Department of Internal Medicine, School of Medicine, Chiba University, Japan. mtakemo@intmed02.m.chiba-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Takemoto
authors.forename: K
authors.initials: K
authors.lastname: Yokote
authors.forename: M
authors.initials: M
authors.lastname: Yamazaki
authors.forename: A L
authors.initials: AL
authors.lastname: Ridall
authors.forename: W T
authors.initials: WT
authors.lastname: Butler
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: K
authors.initials: K
authors.lastname: Tamura
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Mori
mesh_terms: D000818:Animals; D001011:Aorta; D001161:Arteriosclerosis / Q000503:physiopathology; D002448:Cell Adhesion; D002478:Cells, Cultured; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D053495:Osteopontin; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D012795:Sialoglycoproteins / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D011493:Protein Kinase C; D005947:Glucose; C070515:bisindolylmaleimide I