Glycosaminoglycan therapy prevents TGF-beta1 overexpression and pathologic changes in renal tissue of long-term diabetic rats.
Chronic induction of the prosclerotic cytokine transforming growth factor beta (TGF-beta) has been implicated in the pathogenesis of diabetic nephropathy. In a rat model of diabetes mellitus-induced glomerulosclerosis, daily administration of a modified heparin (mH) glycosaminoglycan (GAG) preparation with low anticoagulant activity prevented glomerular and tubular matrix accumulation, as well as overexpression of TGF-beta1 mRNA and albuminuria, without obvious side effects. To elucidate the molecular mechanisms of GAG/mH inhibitory actions on TGF-beta1, studies using cultured mesangial cells were also performed. In these cells, high glucose-induced, dose-dependent increases in TGF-beta1 mRNA and bioactive TGF-beta protein expression were inhibited by GAG/mH treatment, whereas basal TGF-beta1 expression was not affected. Both the heparin-derived GAG and dermatan sulfate were effective, indicating that the heparin chemical structure is not necessary for inhibitory activity. Coincubation of GAG with active TGF-beta1 demonstrated no inhibitory effect on TGF-beta1 bioactivity, excluding a neutralizing effect of GAG on TGF-beta1 a the protein level. Furthermore, it was demonstrated that GAG inhibited phorbol myristate acetate-induced translocation of protein kinase C-alpha (PKC-alpha) and -beta1 and activation of PKC-alpha, as well as high glucose-induced activation of PKC-alpha. These results suggest that GAG inhibit TGF-beta1 overexpression at the transcriptional level, possibly via inhibition of high glucose-activated PKC. The findings indicate the potential of GAG therapy for the prevention of diabetic glomerulosclerosis by the inhibition of chronic disease-induced TGF-beta1 mRNA overexpression.
Ceol
Monica
M
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.|Department of Internal Medicine, Division of Endocrinology, Metabolism, and Pathobiochemistry, University of Tübingen, Tübingen, Germany.
Gambaro
Giovanni
G
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.
Sauer
Ulrich
U
Institute of Pathology, University of Munich, Munich, Germany.
Baggio
Bruno
B
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.
Anglani
Franca
F
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.
Forino
Monica
M
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.
Facchin
Sonia
S
Institute of Internal Medicine, Division of Nephrology, University of Padova, Padova, Italy.|Department of Internal Medicine, Division of Endocrinology, Metabolism, and Pathobiochemistry, University of Tübingen, Tübingen, Germany.
Bordin
Luciana
L
Department of Biochemistry, University of Padova, Padova, Italy.
Weigert
Cora
C
Department of Internal Medicine, Division of Endocrinology, Metabolism, and Pathobiochemistry, University of Tübingen, Tübingen, Germany.
Nerlich
Andreas
A
Institute of Pathology, University of Munich, Munich, Germany.
Schleicher
Erwin D
ED
Department of Internal Medicine, Division of Endocrinology, Metabolism, and Pathobiochemistry, University of Tübingen, Tübingen, Germany.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D002908:Chronic Disease; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D005920:Glomerular Mesangium / Q000378:metabolism / Q000473:pathology; D005947:Glucose / Q000494:pharmacology; D006025:Glycosaminoglycans / Q000627:therapeutic use*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1
D006025:Glycosaminoglycans; D012333:RNA, Messenger; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D011493:Protein Kinase C; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate