title: Mechanical regulation of HB-GAM expression in bone cells.
abstract: Bone adaption upon mechanical stimulation is accompanied by changes in gene expression. In this context we investigated the influence of mechanical loading on heparin binding growth associated molecule (HB-GAM) expression, an extracellular matrix molecule which in cell culture has been shown to stimulate the differentiation of osteoblasts. We obtained information on the participating signal transduction pathways using a mitogenic loading regimen. Specific inhibitors of various signal transduction pathways were added to loaded cells and to unloaded controls. By semi-quantitative PCR studies we demonstrated a rapid decrease of HB-GAM expression in primary osteoblasts and SaOs-2 cells by 20-30% upon mechanical loading within 30min. We showed that the RGD-integrin interaction is involved in the regulation of HB-GAM expression. Furthermore, integrity of the cytoskeleton, stretch-activated, and voltage-sensitive Ca(2+) channels as well as gap junctional communication are necessary for the downregulation of HB-GAM expression by mechanical loading.
authors.affiliation: Institute of Orthopedic Research and Biomechanics, University of Ulm, Germany. astrid.liedert@medizin.uni-ulm.de
authors.forename: Astrid
authors.initials: A
authors.lastname: Liedert
authors.forename: Peter
authors.initials: P
authors.lastname: Augat
authors.forename: Anita
authors.initials: A
authors.lastname: Ignatius
authors.forename: Heinz-Juergen
authors.initials: HJ
authors.lastname: Hausser
authors.forename: Lutz
authors.initials: L
authors.lastname: Claes
mesh_terms: D000368:Aged; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D006034:Glycyrrhetinic Acid / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008934:Mitogens / Q000378:metabolism*; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D016023:Integrins; D008934:Mitogens; D009842:Oligopeptides; C066845:pleiotrophin; C047981:arginyl-glycyl-aspartic acid; D006034:Glycyrrhetinic Acid