title: Overexpression of glutamine:fructose-6-phosphate-amidotransferase induces transforming growth factor-beta1 synthesis in NIH-3T3 fibroblasts.
abstract: Increased flux through the hexosamine biosynthetic pathway with glutamine:fructose-6-phosphate-amidotransferase (GFAT) as rate-limiting enzyme has been linked to the enhanced bioactivity of the prosclerotic cytokine transforming growth factor beta1 (TGF-beta1) in fibrotic complications, particularly in diabetic kidney disease. Here, we investigate in a stable transfection system the effect of overexpression of GFAT on TGF-beta1 synthesis in NIH-3T3 fibroblasts. We demonstrate a 1.8-fold stimulation of TGF-beta1 mRNA and a 1.9-fold increased protein expression, whereas TGF-beta2 production was not upregulated. The 1.5-fold enhanced TGF-beta1 promoter activity suggests a transcriptional regulation. The elevated TGF-beta1 protein is biologically active since GFAT-overexpressing cells exhibit a 2-fold fibronectin production. The results indicate a GFAT-dependent induction of TGF-beta1 synthesis.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Metabolism and Pathobiochemistry, University of Tübingen, D-72076, Tübingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Weigert
authors.forename: K
authors.initials: K
authors.lastname: Brodbeck
authors.forename: R
authors.initials: R
authors.lastname: Lehmann
authors.forename: H U
authors.initials: HU
authors.lastname: Häring
authors.forename: E D
authors.initials: ED
authors.lastname: Schleicher
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D002455:Cell Division; D004797:Enzyme-Linked Immunosorbent Assay; D005353:Fibronectins / Q000032:analysis / Q000096:biosynthesis; D005355:Fibrosis / Q000201:enzymology / Q000378:metabolism; D017930:Genes, Reporter / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000235:genetics / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics*; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2
chemical_list: D005353:Fibronectins; D012333:RNA, Messenger; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D019344:Lactic Acid; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); D005947:Glucose