Expression of hyaluronan synthases and hyaluronidases in the MG63 osteoblast cell line.
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.
Adams
Julian Robert James
JR
Matrix Biology Unit, Department of Genetic Medicine, Children, Youth and Women's Health Service, 72 King William Rd., Nth. Adelaide. SA 5006, Australia.
Sander
Guy
G
Byers
Sharon
S
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*
D006025:Glycosaminoglycans; D007527:Isoenzymes; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D006821:Hyaluronoglucosaminidase