151. Overexpression of glutamine:fructose-6-phosphate-amidotransferase induces transforming growth factor-β1 synthesis in NIH-3T3 fibroblasts
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Katrin Brodbeck, Hans U. Häring, Erwin Schleicher, Rainer Lehmann, and Cora Weigert
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Transcriptional Activation ,medicine.medical_treatment ,Blotting, Western ,Biophysics ,Fructose 6-phosphate ,Enzyme-Linked Immunosorbent Assay ,Diabetic nephropathy ,Transfection ,Biochemistry ,Hexosamine biosynthetic pathway ,Transforming Growth Factor beta1 ,Mice ,Transforming Growth Factor beta2 ,chemistry.chemical_compound ,Genes, Reporter ,Transforming Growth Factor beta ,Structural Biology ,Genetics ,medicine ,Animals ,Lactic Acid ,RNA, Messenger ,Glutamine:fructose-6-phosphate-amidotransferase ,Promoter Regions, Genetic ,Molecular Biology ,Transforming growth factor β ,Glutamine amidotransferase ,Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) ,biology ,3T3 Cells ,Cell Biology ,Transforming growth factor beta ,Fibrosis ,Molecular biology ,Fibronectins ,Glutamine ,Fibronectin ,Glucose ,Cytokine ,chemistry ,biology.protein ,Fibroblast ,Cell Division ,Stable overexpression ,Transforming growth factor - 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.
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