Fluid Flow Induces Rankl Expression in Primary Murine Calvarial Osteoblasts.
From: Department of Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
Journal of cellular biochemistry
- Publish Date: Aug 2006
- ISSN: 0730-2312
- Volume: 98
- Issue: 5
- Pages: 1271-83
- Medium: Print
- Language: English
- Citation (JAMA): Mehrotra Meenal, Saegusa Masatomo, Wadhwa Sunil, et al. Fluid Flow Induces Rankl Expression in Primary Murine Calvarial Osteoblasts.. J. Cell. Biochem. Aug 2006;98:1271-83
Abstract
Mechanical loading of bone generates fluid flow within the mineralized matrix that exerts fluid shear stress (FSS) on cells. We examined effects of FSS on receptor activator of nuclear factor kappa B ligand (RANKL), a critical factor for osteoclast formation. Primary murine osteoblasts were subjected to pulsatile FSS (5 Hz, 10 dynes/cm(2)) for 1 h and then returned to static culture for varying times (post-FSS). Protein levels were measured by Western analysis and mRNA by Northern analysis, RT-PCR and quantitative PCR. There were 20- to 40-fold increases in RANKL mRNA at 2-4 h post-FSS. RANKL protein was induced by 2 h post-FSS and remained elevated for at least 8 h. Effects were independent of cyclooxygenase-2 activity. Small increases (up to three-fold) in mRNA of the decoy receptor for RANKL, osteoprotegerin, were seen. Five min of FSS, followed by static culture, was as effective in stimulating RANKL mRNA as 4 h of continuous FSS. FSS induced cAMP activity, and H-89, a protein kinase A (PKA) inhibitor, blocked the FSS induction of RANKL. H-89 also inhibited the PKC pathway, but specific PKC inhibitors, GF109203X and Go6983, did not inhibit FSS-induced RANKL. FSS induced phosphorylation of ERK1/2, and PD98059, an inhibitor of the ERK pathway, inhibited the FSS induction of RANKL mRNA 60%-90%. Thus, brief exposure to FSS resulted in sustained induction of RANKL expression after stopping FSS, and this induction was dependent on PKA and ERK signaling pathways. Increased RANKL after mechanical loading may play a role in initiating bone remodeling.
Mesh Headings (Keywords): Animals, Carrier Proteins, Cells, Cultured, Culture Media, Cyclic AMP-Dependent Protein Kinases, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Extracellular Signal-Regulated MAP Kinases, Gene Expression Regulation, Glycoproteins, Membrane Glycoproteins, Mice, Osteoblasts, Osteoprotegerin, Protein Kinase C, RANK Ligand, RNA, Messenger, Receptor Activator of Nuclear Factor-kappa B, Receptors, Cytoplasmic and Nuclear, Receptors, Tumor Necrosis Factor, Rheology, Signal Transduction, Skull
Check for Full Text / PubMed Unique Identifier (PMID): 16514640
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.