Stimulation of collagen gene expression and protein synthesis in murine mesangial cells by high glucose is mediated by autocrine activation of transforming growth factor-beta.
Previous investigations have demonstrated that growing mesangial cells in high glucose concentration stimulates extracellular matrix synthesis and also increases the expression of TGF-beta. We tested whether the stimulation of extracellular matrix production is mediated by autocrine activation of TGF-beta, a known prosclerotic cytokine. Addition of neutralizing anti-TGF-beta antibody, but not normal rabbit IgG, significantly reduced the high glucose-stimulated incorporation of 3[H]proline. Denaturing SDS-PAGE revealed that mainly collagen types I and IV were stimulated by high (450 mg/dl) D-glucose. This high glucose-mediated increase in collagen synthesis was reduced by the anti-TGF-beta antibody. Treatment of mesangial cells grown in normal (100 mg/dl) D-glucose with 2 ng/ml recombinant TGF-beta 1 mimicked the effects of high glucose. Furthermore, the anti-TGF-beta antibody significantly reduced the increase in mRNA levels encoding alpha 2(I) and alpha 1(IV) collagens induced by high glucose. Thus, the high glucose-stimulated increase of collagen production in mesangial cells is mediated, at least in part, by autocrine TGF-beta activation. We postulate that the interception of the glomerular activity of TGF-beta may be an effective intervention in the management of diabetic nephropathy.
Ziyadeh
F N
FN
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6144.
Sharma
K
K
Ericksen
M
M
Wolf
G
G
D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D015870:Gene Expression / Q000187:drug effects*; D005920:Glomerular Mesangium / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D007074:Immunoglobulin G / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D011392:Proline / Q000378:metabolism; D014176:Protein Biosynthesis; D011817:Rabbits / Q000276:immunology; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000276:immunology / Q000502:physiology*
D000906:Antibodies; D016326:Extracellular Matrix Proteins; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D003094:Collagen; D011392:Proline; D005947:Glucose