title: High glucose-induced upregulation of osteopontin is mediated via Rho/Rho kinase pathway in cultured rat aortic smooth muscle cells.
abstract: OBJECTIVE
  Osteopontin is upregulated in the diabetic vascular wall and in vascular smooth muscle cells cultured under high glucose concentration. In the present study, we analyzed the mechanism of high glucose-induced upregulation of osteopontin in cultured rat aortic smooth muscle cells.
  
  
  RESULTS
  We found that an inhibitor of Rho-associated protein kinase, Y-27632, suppressed osteopontin mRNA expression under high glucose concentration. Transfection of cells with a constitutive active Rho mutant, pSRalpha-myc-RhoDA, enhanced osteopontin mRNA expression. Furthermore, incubation of cells under high glucose concentration activated Rho, indicating that Rho/Rho kinase pathway mediates high-glucose-stimulated osteopontin expression. Treatment of cells with an inhibitor of protein kinase C, GF109203X, and azaserine, an inhibitor of the hexosamine pathway, suppressed high glucose-induced Rho activation. Glucosamine treatment was shown to activate Rho. Treatment of cells with an inhibitor of MEK1, PD98059, suppressed osteopontin mRNA expression under high glucose concentration. Incubation of cells under high glucose concentration activated ERK. Finally, transfection of cells with pSRalpha-myc-RhoDA also activated ERK.
  
  
  CONCLUSIONS
  In conclusion, our present findings support a notion that Rho/Rho kinase pathway functions downstream of protein kinase C and the hexosamine pathways and upstream of ERK in mediating high-glucose-induced upregulation of osteopontin expression.
authors.affiliation: Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan.
authors.forename: Harukiyo
authors.initials: H
authors.lastname: Kawamura
authors.forename: Koutaro
authors.initials: K
authors.lastname: Yokote
authors.forename: Sunao
authors.initials: S
authors.lastname: Asaumi
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Masaki
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Maezawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Saito
authors.forename: Seijiro
authors.initials: S
authors.lastname: Mori
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism*; D053495:Osteopontin; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017368:Protein Prenylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012795:Sialoglycoproteins / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology*; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000577:Amides; D004791:Enzyme Inhibitors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007211:Indoles; D047908:Intracellular Signaling Peptides and Proteins; D008301:Maleimides; D011725:Pyridines; D011804:Quinolines; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; C108830:Y 27632; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D020742:rhoA GTP-Binding Protein; D005947:Glucose; C070515:bisindolylmaleimide I; C108475:pitavastatin