title: Expression of hyaluronan synthases and hyaluronidases in the MG63 osteoblast cell line.
abstract: The expression of hyaluronan synthases (1, 2 and 3) and hyaluronidases (1, 2, 3, 4 and PH20) was examined in the MG63 osteoblast cell line induced to mineralize in vitro and compared to the rate of glycosaminoglycan production. Real-time PCR analysis demonstrated a 13-fold decrease in hyaluronan synthase 3 expression in mineralising MG63 cells; no significant change in hyaluronan synthase 2 expression in mineralising cells and hyaluronan synthase 1 was not expressed. In mineralising MG63 cells a 62-fold increase in hyaluronidase 2, a 13-fold increase in hyaluronidase 3, and a 3-fold increase in hyaluronidase 4 expression were observed when compared to non-mineralising cells; hyaluronidase 1 and PH20 expression was not detected. After 5 weeks in mineralising culture conditions a 2-fold increase in total 3H-glucosamine incorporation was observed in cells when compared to 24 h or 5 week control cultures. This was made up of a 5-fold decrease in hyaluronan production, a 2-fold increase in chondroitin sulphate/dermatan sulphate and a 10-fold increase in 3H-glucosamine incorporation into the non-glycosaminoglycan fraction. A 3-fold increase in 35SO4 incorporation into chondroitin sulphate/dermatan sulphate was also observed. Thus there is co-ordinate expression of genes that control hyaluronan metabolism such that there is a general decrease in the expression of hyaluronan synthases, an increase in the expression of hyaluronidases and a corresponding decrease in hyaluronan production by mineralising MG63 cells.
authors.affiliation: Matrix Biology Unit, Department of Genetic Medicine, Children, Youth and Women's Health Service, 72 King William Rd., Nth. Adelaide. SA 5006, Australia.
authors.forename: Julian Robert James
authors.initials: JR
authors.lastname: Adams
authors.forename: Guy
authors.initials: G
authors.lastname: Sander
authors.forename: Sharon
authors.initials: S
authors.lastname: Byers
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D000076002:Hyaluronan Synthases; D006821:Hyaluronoglucosaminidase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*
chemical_list: D006025:Glycosaminoglycans; D007527:Isoenzymes; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D006821:Hyaluronoglucosaminidase