title: Transforming growth factor beta1-regulated xylosyltransferase I activity in human cardiac fibroblasts and its impact for myocardial remodeling.
abstract: In cardiac fibrosis remodeling of the failing myocardium is associated with a complex reorganization of the extracellular matrix (ECM). Xylosyltransferase I and Xylosyltransferase II (XT-I and XT-II) are the key enzymes in proteoglycan biosynthesis, which are an important fraction of the ECM. XT-I was shown to be a measure for the proteoglycan biosynthesis rate and a biochemical fibrosis marker. Here, we investigated the XT-I and XT-II expression in cardiac fibroblasts and in patients with dilated cardiomyopathy and compared our findings with nonfailing donor hearts. We analyzed XT-I and XT-II expression and the glycosaminoglycan (GAG) content in human cardiac fibroblasts incubated with transforming growth factor (TGF)-beta(1) or exposed to cyclic mechanical stretch. In vitro and in vivo no significant changes in the XT-II expression were detected. For XT-I we found an increased expression in parallel with an elevated chondroitin sulfate-GAG content after incubation with TGF-beta(1) and after mechanical stretch. XT-I expression and subsequently increased levels of GAGs could be reduced with neutralizing anti-TGF-beta(1) antibodies or by specific inhibition of the activin receptor-like kinase 5 or the p38 mitogen-activated protein kinase pathway. Usage of XT-I small interfering RNA could specifically block the increased XT-I expression under mechanical stress and resulted in a significantly reduced chondroitin sulfate-GAG content. In the left and right ventricular samples of dilated cardiomyopathy patients, our data show increased amounts of XT-I mRNA compared with nonfailing controls. Patients had raised levels of XT-I enzyme activity and an elevated proteoglycan content. Myocardial remodeling is characterized by increased XT-I expression and enhanced proteoglycan deposition. TGF-beta(1) and mechanical stress induce XT-I expression in cardiac fibroblasts and have impact for ECM remodeling in the dilated heart. Specific blocking of XT-I expression confirmed that XT-I catalyzes a rate-limiting step during fibrotic GAG biosynthesis.
authors.affiliation: Institut für Laboratoriumsund Transfusionsmedizin, Herzund Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Georgstrasse 11, 32545 Bad Oeynhausen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Prante
authors.forename: Hendrik
authors.initials: H
authors.lastname: Milting
authors.forename: Astrid
authors.initials: A
authors.lastname: Kassner
authors.forename: Martin
authors.initials: M
authors.lastname: Farr
authors.forename: Michael
authors.initials: M
authors.lastname: Ambrosius
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schön
authors.forename: Daniela G
authors.initials: DG
authors.lastname: Seidler
authors.forename: Aly El
authors.initials: AE
authors.lastname: Banayosy
authors.forename: Reiner
authors.initials: R
authors.lastname: Körfer
authors.forename: Joachim
authors.initials: J
authors.lastname: Kuhn
authors.forename: Knut
authors.initials: K
authors.lastname: Kleesiek
authors.forename: Christian
authors.initials: C
authors.lastname: Götting
mesh_terms: D029404:Activin Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D000906:Antibodies / Q000494:pharmacology; D002311:Cardiomyopathy, Dilated / Q000201:enzymology* / Q000473:pathology; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000096:biosynthesis; D005109:Extracellular Matrix / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000201:enzymology* / Q000473:pathology; D005355:Fibrosis; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006352:Heart Ventricles / Q000201:enzymology / Q000473:pathology; D006801:Humans; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D010430:Pentosyltransferases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D013314:Stress, Mechanical; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000097608:UDP Xylose-Protein Xylosyltransferase
chemical_list: D029404:Activin Receptors; D000906:Antibodies; D002809:Chondroitin Sulfates; D010430:Pentosyltransferases; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; D053773:Transforming Growth Factor beta1; D048051:p38 Mitogen-Activated Protein Kinases; D000097608:UDP Xylose-Protein Xylosyltransferase