The long term goals of this study are to definitively analyze the alterations in the in vivo pericellular matrix due to osteoarthritis and to determine how these changes affect cartilage maintenance and repair. Previous studies have reported that the pericellular region in osteoarthritic cartilage becomes enlarged and enriched in specific matrix molecules such as type VI collagen. These changes are important because all molecules which leave or enter the cell must pass through this interface between the chondrocyte and the cartilage matrix. During their passage, some of these molecules, such as growth factors, are modified or retained.
The specific aims of this proposal are: (l) to determine how the molecular composition and organization of the pericellular matrix in osteoarthritic human cartilage differs from that in normal human cartilage, (2) to determine how the macromolecules enriched in the osteoarthritic pericellular matrix are associated with other matrix components and how these associations produce the observed matrix structure, (3) to relate changes in the in vivo pericellular matrix with alterations in chondrocyte metabolism in vitro, and (4) to determine how the structure - and composition of the pericellular matrix affects extracellular matrix assembly. The studies to accomplish these aims will make use of the PI's recently developed technique to conveniently isolate """"""""chondrons"""""""": chondrocytes with their in vivo pericellular matrix and surrounding capsule. These chondrons are viable, obtained in good yield, and can be maintained in alginate head culture for several months. The in vivo pericellular matrix can now be studied independently of the surrounding interterritorial cartilage matrix. Chondrons and traditionally isolated chondrocytes will be obtained from normal and osteoarthritic adult human cartilage, maintained in alginate bead culture, and compared. The dynamic structure and composition of the pericellular matrix in living and fixed chondrons will be examined with confocal microscopy, nanovid microscopy (video-enhanced light microscopy combined with colloidal gold probes conjugated to monoclonal antibodies), and transmission electron microscopy. Chondrocyte metabolism in vitro will be studied with a variety of techniques including in situ hybridization, immunofluorescence, and SDS-PAGE with Western blotting. In addition to defining the changes in the pericellular matrix due to osteoarthritis, these studies provide for the characterization of an important new model system for studying the metabolism of osteoarthritic chondrocytes in vitro.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29AR043883-04
Application #
2769636
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Project Start
1995-09-25
Project End
2000-08-31
Budget Start
1998-09-01
Budget End
1999-08-31
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Zhang, Z; Fan, J; Becker, K G et al. (2006) Comparison of gene expression profile between human chondrons and chondrocytes: a cDNA microarray study. Osteoarthritis Cartilage 14:449-59
Graff, Ronald D; Lee, Greta M (2003) Microplate live cell assay system for early events in mechanotransduction. Anal Biochem 318:181-6
Summey Jr, Brett T; Graff, Ronald D; Lai, Thung-Sheng et al. (2002) Tissue transglutaminase localization and activity regulation in the extracellular matrix of articular cartilage. J Orthop Res 20:76-82
Larson, Christopher M; Kelley, Scott S; Blackwood, A Denene et al. (2002) Retention of the native chondrocyte pericellular matrix results in significantly improved matrix production. Matrix Biol 21:349-59
Lee, Greta M; Tioran, Marianne E; Jansen, Marilyn et al. (2002) Development of selective tolerance to interleukin-1beta by human chondrocytes in vitro. J Cell Physiol 192:113-24
Trickey, W R; Lee, G M; Guilak, F (2000) Viscoelastic properties of chondrocytes from normal and osteoarthritic human cartilage. J Orthop Res 18:891-8
Lee, G M; Paul, T A; Slabaugh, M et al. (2000) The incidence of enlarged chondrons in normal and osteoarthritic human cartilage and their relative matrix density. Osteoarthritis Cartilage 8:44-52
Graff, R D; Lazarowski, E R; Banes, A J et al. (2000) ATP release by mechanically loaded porcine chondrons in pellet culture. Arthritis Rheum 43:1571-9
Lee, G M; Loeser, R F (1999) Cell surface receptors transmit sufficient force to bend collagen fibrils. Exp Cell Res 248:294-305
Guilak, F; Jones, W R; Ting-Beall, H P et al. (1999) The deformation behavior and mechanical properties of chondrocytes in articular cartilage. Osteoarthritis Cartilage 7:59-70

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