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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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Animals
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Blotting, Western
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Cell Division
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Enzyme-Linked Immunosorbent Assay
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Fibronectins / analysis
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Fibronectins / biosynthesis
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Fibrosis / enzymology
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Fibrosis / metabolism
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Genes, Reporter / genetics
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Glucose / metabolism
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Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / genetics
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Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / metabolism*
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Lactic Acid / metabolism
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Mice
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Promoter Regions, Genetic / genetics
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Transcriptional Activation*
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Transfection
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Transforming Growth Factor beta / analysis
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Transforming Growth Factor beta / biosynthesis*
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Transforming Growth Factor beta / genetics*
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Transforming Growth Factor beta1
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Transforming Growth Factor beta2
Substances
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Fibronectins
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RNA, Messenger
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Tgfb1 protein, mouse
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Transforming Growth Factor beta
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Transforming Growth Factor beta1
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Transforming Growth Factor beta2
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Lactic Acid
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Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)
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Glucose