title: Glycosyltransferases and glycosaminoglycans in bleomycin and transforming growth factor-β1-induced pulmonary fibrosis.
abstract: Glycosaminoglycan (GAG) chains of proteoglycans (PGs) play important roles in fibrosis through cell-matrix interactions and growth factor binding in the extracellular matrix. We investigated the expression and regulation of PG core protein (versican) and key enzymes (xylosyltransferase [XT]-I, β1,3-glucuronosyltransferase [GlcAT]-I, chondroitin-4-sulfotransferase [C4ST]) implicated in synthesis and sulfation of GAGs in bleomycin (BLM) and adenovirus-transforming growth factor (TGF)-β1-induced lung fibrosis in rats. We also studied the role of GlcAT-I or TGF-β1 and the signaling pathways regulating PG-GAG production in primary lung fibroblasts isolated from saline- or BLM-instilled rats. The mRNA for XT-I, GlcAT-I, C4ST, and versican was increased in the lung 14 days after BLM injury. In vitro studies indicate that fibrotic lung fibroblasts (FLFs) expressed more XT-I, C4ST, and chondroitin sulfate (CS)-GAGs than did normal lung fibroblasts at baseline. TGF-β1 enhanced the expression of XT-I, C4ST-I, and versican in normal lung fibroblasts, whereas SB203580 or SB431542, by targeting p38 mitogen-activated protein kinase or TGF-β type-1 receptor/activin receptor-like kinase 5, respectively, attenuated the response to both TGF-β1 and FLFs on PG-GAG expression. Neutralizing anti-TGF-β1 antibody abrogated FLF-conditioned medium-stimulated expression of XT-I, GlcAT-I, versican, and CS-GAG. Forced expression of TGF-β1 in vivo enhanced versican, XT-I, GlcAT-I, and C4ST-I expression and PG-GAG deposition in rat lungs. Finally, induced expression of GlcAT-I gene in rat lung fibroblasts increased GAG synthesis by these cells. Together, our results provide new insights into the basis for increased PG-GAG deposition in lung fibrosis; inhibition of TGF-β1-mediated or fibrosis-induced PG-GAG production by activin receptor-like kinase 5/p38 inhibitors may contribute to antifibrotic activity.
authors.affiliation: 1 Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
authors.forename: Narayanan
authors.initials: N
authors.lastname: Venkatesan
authors.forename: Kimitake
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Martin
authors.initials: M
authors.lastname: Kolb
authors.forename: Laszlo
authors.initials: L
authors.lastname: Farkas
authors.forename: Mustapha
authors.initials: M
authors.lastname: Bourhim
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ouzzine
authors.forename: Mara S
authors.initials: MS
authors.lastname: Ludwig
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001761:Bleomycin; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000378:metabolism; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000201:enzymology / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic; D014453:Glucuronosyltransferase / Q000378:metabolism; D006025:Glycosaminoglycans / Q000235:genetics / Q000378:metabolism*; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D010430:Pentosyltransferases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D015238:Sulfotransferases / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D053675:Versicans / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000097608:UDP Xylose-Protein Xylosyltransferase
chemical_list: D057134:Antibodies, Neutralizing; D001761:Bleomycin; D002809:Chondroitin Sulfates; D014453:Glucuronosyltransferase; D006025:Glycosaminoglycans; D016695:Glycosyltransferases; D010430:Pentosyltransferases; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta; D015238:Sulfotransferases; D053773:Transforming Growth Factor beta1; D053675:Versicans; D048051:p38 Mitogen-Activated Protein Kinases; D000097608:UDP Xylose-Protein Xylosyltransferase; C508324:Vcan protein, rat; C067806:glucuronyltransferase GlcAT-1; C000625843:Tgfbr1 protein, rat; C019893:chondroitin 4-sulfotransferase