Glucose-induced TGF-beta1 and TGF-beta receptor-1 expression in vascular smooth muscle cells is mediated by protein kinase C-alpha.
Sclerosis and increased matrix expression in diabetes are mediated by glucose-induced transforming growth factor (TGF)-beta1 expression. The intracellular effects of high glucose occur at least in part by way of protein kinase C (PKC). We previously described a role for PKC-alpha in glucose-induced permeability. We now investigated the hypothesis that glucose-induced expression of TGF-beta1 and its receptors (TGF-beta-R1 and -R2) are mediated by activation of this PKC isoform. TGF-beta1 and TGF-beta-R expressions were determined in vascular smooth muscle cells (VSMCs) by immunocytochemistry and Western blotting. PKC isoforms were assessed by confocal microscopy. PKC isoforms were inhibited with antisense oligodeoxynucleotides. PKC-alpha was upregulated by overexpression or microinjection. High glucose (20 mmol/L) increased VSMC TGF-beta1 and TGF-beta-R1 expression but not TGF-beta-R2 expression. PKC inhibitors and specific PKC-alpha downregulation by antisense treatment prevented this effect, whereas antisense treatment against PKC-beta, -epsilon, and -zeta had no influence. PKC-alpha overexpression increased TGF-beta1 and TGF-beta-R1 expression but not TGF-beta-R2 expression. PKC-alpha microinjection into individual VSMCs also increased TGF-beta1 and TGF-beta-R immunofluorescence. Last, VSMCs from PKC-alpha-deficient mice did not respond to high glucose compared with VSMCs from wild-type mice. We propose that high glucose-induced TGF-beta1 and TGF-beta-R1 expression is mediated by PKC-alpha. Our findings suggest an autocrine feedback mechanism and a possible role for PKC-alpha in diabetic vascular disease.
Lindschau
Carsten
C
Department of Nephrology, Medical School Hannover, Germany.
Quass
Petra
P
Menne
Jan
J
Güler
Faikah
F
Fiebeler
Anette
A
Leitges
Michael
M
Luft
Friedrich C
FC
Haller
Hermann
H
D030201:Activin Receptors, Type I / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009281:Naphthalenes / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019311:Staurosporine / Q000494:pharmacology; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D053773:Transforming Growth Factor beta1
D004791:Enzyme Inhibitors; D008164:Luminescent Proteins; D009281:Naphthalenes; D016376:Oligonucleotides, Antisense; D018125:Receptors, Transforming Growth Factor beta; D011993:Recombinant Fusion Proteins; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C061465:calphostin complex; D049452:Green Fluorescent Proteins; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625843:Tgfbr1 protein, rat; D019311:Staurosporine; D005947:Glucose