Development of long term marrow cultures which form osteoclast-like multinucleated cells (MNC) from mononuclear precursors, has allowed us to characterize the mechanism of action of osteotropic factors which regulate osteoclast formation. Although these culture systems have been extremely useful for these studies, they are limited by the fact that they are composed of heterogeneous cell populations, making it impossible to determine: 1) the molecular mechanisms involved in the differentiation of osteoclast precursors to mature osteoclasts, 2) the identity of the osteoclast precursor(s), or 3) if osteotropic factors act directly on osteoclast precursors. Such studies require purified populations of osteoclast precursors. To overcome these limitations, we have recently developed monoclonal antibodies to these MNC. The monoclonal antibodies react with a subpopulation of marrow mononuclear cells and freshly isolated osteoclasts from fetal baboons as well as MNC, suggesting that they may react with MNC precursors. The antibodies do not cross-react with peripheral blood monocytes or macrophage polykaryons demonstrating that they are not directed against macrophage antigens. With development of these reagents we can no initiate studies to purify and characterize osteoclast precursors. In this proposal we will: 1) further characterize these newly developed anti-MNC monoclonal antibodies and test their ability to purify osteoclast precursors from human bone marrow. If purified populations of MNC precursors are obtained, we will use these purified precursor populations to identify the cell lineage of the osteoclast by determining the antigenic phenotype of the osteoclast precursor(s) and determine the effects of osteotropic factors on purified populations of osteoclasts precursors. 2) extend our culture studies in which we have developed semi-solid culture systems which permit the clonal growth of committed osteoclast (OCL) precursors. These clones will be used to raise monoclonal antibodies against the committed OCL precursor. These antibodies should be useful in purification of OCL precursors and identification of unique differentiation antigens present on early OCL precursors ; 3) transfect human marrow cell populations containing OCL precursors with recombinant adenoviruses to determine if OCL precursors can be transformed, and identify the growth conditions required for their maturation to osteoclasts.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR035188-08
Application #
2079031
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1985-09-01
Project End
1995-08-14
Budget Start
1994-04-01
Budget End
1995-08-14
Support Year
8
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Mills, B G; Frausto, A; Singer, F R et al. (1994) Multinucleated cells formed in vitro from Paget's bone marrow express viral antigens. Bone 15:443-8
Mundy, G R; Roodman, G D; Bonewald, L F et al. (1992) Effects of TNF and lymphotoxin on bone cells. Immunol Ser 56:483-98
Roodman, G D; Kurihara, N; Ohsaki, Y et al. (1992) Interleukin 6. A potential autocrine/paracrine factor in Paget's disease of bone. J Clin Invest 89:46-52
Mundy, G R (1991) Inflammatory mediators and the destruction of bone. J Periodontal Res 26:213-7