Osteoclasts utilize the integrin alphabeta3 to mediate attachment to bone, the initial step in athe resorptive process. We find, in a murine system of in vitro osteoclastogenesis, precursor cells initially express and utilize the integrin alphabeta5 and not alphabeta3 and that, during formation of bone-resorbing polykaryons, alphabeta5 and alphabeta3 levels fall and rise respectively. This reciprocal change in levels of two functional integrins can be replicated by treating osteoclast precursors with GM-CSF, a cytokine involved in osteoclast differentiation. Levels of beta5 and beta3 mRNA fall alphabeta5 and alphabeta3 regulation is mediated through GM-CSF-dependent alterations in beta5 and beta3 gene expression. GM-CSF regulates gene expression by phosphorylation of STAT5, a cytosol- residing transcription factor, two isoforms of which have been cloned in mouse. The activated STAT5 translocates to the nucleus, where it binds to specific sequences in target genes, resulting in new protein synthesis. Most importantly as regards this proposal, the promoter region of the murine beta3 contains multiple STAT binding sequences. Based on our findings, and athe current model of GM-CSF action, we hypothesize that 1) specific STAT5 isoforms bind to and mediate GM-CSF expression of the murine beta3 gene and 2) GM-CSF inhibits murine beta5 gene expression through a cis-acting DNA sequence. Thus, our specific aims are; 1. CHARACTERIZE THE STAT5 ISOFORMS AND ASSOCIATED DNA BINDING DOMAINS WHICH MEDIATE GM-CSF REGULATION OF THE MURINE BETA3 GENE; 2. IDENTIFY THE DNA SEQUENCE BY WHICH GM-CSF INHIBITS EXPRESSION OF THE MURINE BETA5 GENE.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR042404-05
Application #
2442824
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
1993-05-01
Project End
1999-06-30
Budget Start
1997-07-01
Budget End
1998-06-30
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Barnes-Jewish Hospital
Department
Type
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63110
Feng, Xu; Takeshita, Sunao; Namba, Noriyuki et al. (2002) Tyrosines 559 and 807 in the cytoplasmic tail of the macrophage colony-stimulating factor receptor play distinct roles in osteoclast differentiation and function. Endocrinology 143:4868-74
Wei, S; Teitelbaum, S L; Wang, M W et al. (2001) Receptor activator of nuclear factor-kappa b ligand activates nuclear factor-kappa b in osteoclast precursors. Endocrinology 142:1290-5
Srivastava, S; Toraldo, G; Weitzmann, M N et al. (2001) Estrogen decreases osteoclast formation by down-regulating receptor activator of NF-kappa B ligand (RANKL)-induced JNK activation. J Biol Chem 276:8836-40
Feng, X; Novack, D V; Faccio, R et al. (2001) A Glanzmann's mutation in beta 3 integrin specifically impairs osteoclast function. J Clin Invest 107:1137-44
McHugh, K P; Kitazawa, S; Teitelbaum, S L et al. (2001) Cloning and characterization of the murine beta(3) integrin gene promoter: identification of an interleukin-4 responsive element and regulation by STAT-6. J Cell Biochem 81:320-32
Legler, D F; Wiedle, G; Ross, F P et al. (2001) Superactivation of integrin alphavbeta3 by low antagonist concentrations. J Cell Sci 114:1545-53
McHugh, K P; Hodivala-Dilke, K; Zheng, M H et al. (2000) Mice lacking beta3 integrins are osteosclerotic because of dysfunctional osteoclasts. J Clin Invest 105:433-40
Lai, C F; Feng, X; Nishimura, R et al. (2000) Transforming growth factor-beta up-regulates the beta 5 integrin subunit expression via Sp1 and Smad signaling. J Biol Chem 275:36400-6
Cheng, S L; Lai, C F; Fausto, A et al. (2000) Regulation of alphaVbeta3 and alphaVbeta5 integrins by dexamethasone in normal human osteoblastic cells. J Cell Biochem 77:265-76
Abu-Amer, Y; Erdmann, J; Alexopoulou, L et al. (2000) Tumor necrosis factor receptors types 1 and 2 differentially regulate osteoclastogenesis. J Biol Chem 275:27307-10

Showing the most recent 10 out of 27 publications