title: Mechanical stress induces COX-2 mRNA expression in bone cells from elderly women.
abstract: Mechanical loading-induced fluid flow in the lacuno-canalicular network is a possible signal for bone cell adaptive responses. In an earlier study we found that pulsating fluid flow (PFF, 0.7+/-0.02 Pa, 5 Hz, 0.4 Pa/s) stimulates the production of prostaglandins by neonatal mouse calvarial cells. In addition, mRNA expression of the inducible form of cyclooxygenase (COX-2), but not the constitutive form (COX-1), the major enzymes in prostaglandin production, was increased by PFF. The present study was performed to determine whether human primary bone cells from the iliac crest, respond to mechanical stress in a similar way as neonatal mouse calvarial cells. We subjected bone cells originating from the iliac crest of nine elderly women, between 56 and 80 yr of age, for 1 h to PFF and measured prostaglandin production and COX-1 and COX-2 mRNA expression. One hour PFF treatment stimulated the release of PGE2 by 3.5 fold and PGI2 by 2.2 fold. PFF also increased the expression of COX-2 mRNA by 2.9 fold, but did not change COX-1 mRNA. No correlation was found between donor age and PFF effect, neither on prostaglandin production nor on COX-2 mRNA expression. This study shows that bone cells from the iliac crest of elderly women react to PFF treatment in a similar way as neonatal mouse calvarial cells, namely with increased production of prostaglandins and upregulation of COX-2 mRNA expression. These results suggest that human bone cells from the iliac crest and neonatal mouse calvarial cells share a similar mechanotransduction pathway.
authors.affiliation: Department of Oral Cell Biology, ACTA-Vrije Universiteit, Amsterdam, Netherlands. m.joldersma.ocb.acta@med.vu.nl
authors.forename: M
authors.initials: M
authors.lastname: Joldersma
authors.forename: E H
authors.initials: EH
authors.lastname: Burger
authors.forename: C M
authors.initials: CM
authors.lastname: Semeins
authors.forename: J
authors.initials: J
authors.lastname: Klein-Nulend
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001842:Bone and Bones / Q000378:metabolism*; D002478:Cells, Cultured; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D008565:Membrane Proteins; D051379:Mice; D008875:Middle Aged; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D017931:DNA Primers; D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse