Human Molecular Genetics Advance Access published online on December 24, 2007
Human Molecular Genetics, doi:10.1093/hmg/ddm372
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Changes in heparan sulfate are associated with delayed wound repair, altered cell migration, adhesion and contractility in the galactosyltransferase I (ß4GalT-7) deficient form of Ehlers-Danlos syndrome
1 Department of Gynecology and Obstetrics, University of Münster, Medical Center, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany 2 Department of Medical Biochemistry and Microbiology, The Biomedical Center, Uppsala University, SE-75123 Uppsala, Sweden 3 Department of Anatomy, National University of Singapore, 117597 Singapore 4 Department of Biochemistry, NCMLS, Radboud University Nijmegen Medical Center, 6500 HB Nijmegen, he Netherlands 5 Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, D-30625 Hannover, Germany
* corresponding author: Department of Gynecology and Obstetrics, University of Münster Medical Center, Research Laboratory Domagkstr. 11, D-48149 Münster, Germany, phone: +49-251-8356117, fax: +49-251-8355928, e-mail: martingotte{at}uni-muenster.de
Received September 10, 2007; Revised December 18, 2007; Accepted December 19, 2007
Reduced activity of β-galactosyltransferase 7 (ß4GalT-7), an enzyme involved in synthesizing the glycosaminoglycan linkage region of proteoglycans, is associated with the progeroid form of Ehlers-Danlos syndrome (EDS). In the invertebrates Drosophila melanogaster and Caenorhabditis elegans, mutations in ß4GalT-7 affect biosynthesis of heparan sulfate (HS), a modulator of several biological processes relevant to wound repair. We have analyzed structural alterations of HS and their functional consequences in human ß4GalT-7Arg270Cys mutant EDS and control fibroblasts. HS disaccharide analysis by reversed phase ion-pairing chromatography revealed a reduced sulfation degree of HS paralleled by altered immunostaining patterns for the phage-display anti-HS antibodies HS4E4 and RB4EA12 in ß4GalT-7 mutant fibroblasts. Real-time PCR-analysis of 44 genes involved in glycosaminoglycan biosynthesis indicated that the structural alterations in HS were not caused by differential regulation at the transcriptional level. Scratch wound closure was delayed in ß4GalT-7-deficient cells, which could be mimicked by enzymatic removal of HS in control cells. siRNA-mediated knockdown of ß4GalT-7 expression induced morphological changes in control fibroblasts which suggested altered cell-matrix interactions. Adhesion of ß4GalT-7 deficient cells to fibronectin was increased while actin stress fiber formation was impaired relative to control cells. Also collagen gel contraction was delayed in the ß4GalT-7 mutants which showed a reduced formation of pseudopodia and filopodia, less efficient penetration of the collagen gels, and a diminished formation of collagen suprastructures. Our study suggests an HS-dependent basic mechanism behind the altered wound repair phenotype of ß4GalT-7-deficient EDS patients.
equal contribution