title: Differential stimulation of prostaglandin G/H synthase-2 in osteocytes and other osteogenic cells by pulsating fluid flow.
abstract: Mechanical stress produces flow of fluid in the osteocytic lacunar-canalicular network, which is likely the physiological signal for the adaptive response of bone. We compared the induction of prostaglandin G/H synthase-2 (PGHS-2) by pulsating fluid flow (PFF) and serum in osteocytes, osteoblasts, and periosteal fibroblasts, isolated from 18-day-old fetal chicken calvariae. A serum-deprived mixed population of primarily osteocytes and osteoblasts responded to serum with a two- to threefold induction of PGHS-2 mRNA. Serum stimulated PGHS-2-derived PGE(2) release from osteoblasts and osteocytes but not from periosteal fibroblasts as NS-398, a PGHS-2 blocker, inhibited PGE(2) release from osteocytes and osteoblasts with 65%, but not that from periosteal fibroblasts. On the other hand PFF (0.7 Pa, 5 Hz) stimulated (3 fold) PGHS-2 mRNA only in OCY. The related PGE(2) response could be completely inhibited by NS-398. We conclude that osteocytes have a higher intrinsic sensitivity for loading-derived fluid flow than osteoblasts or periosteal fibroblasts.
authors.affiliation: Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands. I.Westbroek@lumc.nl
authors.forename: I
authors.initials: I
authors.lastname: Westbroek
authors.forename: N E
authors.initials: NE
authors.lastname: Ajubi
authors.forename: M J
authors.initials: MJ
authors.lastname: Alblas
authors.forename: C M
authors.initials: CM
authors.lastname: Semeins
authors.forename: J
authors.initials: J
authors.lastname: Klein-Nulend
authors.forename: E H
authors.initials: EH
authors.lastname: Burger
authors.forename: P J
authors.initials: PJ
authors.lastname: Nijweide
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D051546:Cyclooxygenase 2; D004789:Enzyme Activation; D004790:Enzyme Induction; D005347:Fibroblasts / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism; D010011:Osteocytes / Q000201:enzymology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D011673:Pulsatile Flow / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases