1995 Fiscal Year Final Research Report Summary
Study on interaction of integrins with extracellular matrix in proliferation of chondrocytes
| Project/Area Number |
06671853
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
IWAMOTO Motomi Osaka University, Faculty of Dentistry, Assistant Professor, 歯学部, 講師 (80203644)
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| Co-Investigator(Kenkyū-buntansha) |
NAKASHIMA Kazuhisa Osaka University, Faculty of Dentistry, Assistant Researcher, 歯学部, 助手 (90252692)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Chondrocytes / Integrins / Cell Proliferation / Fibronectin |
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| Research Abstract |
We investigated which extracellular matrix and which integrins are involved in chondrocyte adhesion and spreading, and in the control of proliferation. Rabbit growth plate chondrocytes were able to attach to substrates coated with type 1 collagen, type 11 collagen or fibronectin within 24 hours. The initial attachment of chondrocytes to fibronectin substrate was specifically counteracted by treatment with RGD peptide, anti-alpha5beta1 integrin or anti-fibronectin antibody, indicating that attachment involved alpha5beta1 integrin. In contrast, initial adhesion to collagen substrates appeared to be independent on alpha5beta1 integrin intervention. By day 3 of culture, chondrocytes spread onto the various substrates tested. We found that regardless of the nature of the substrate, spreading was reversed by treatment with RGD peptide or antibodies against alpha5beta1 or fibronectin, indicating that cell spreading involved alpha5beta1 and fibronectin endogenously produced and deposited by the chondrocytes themselves. To analyze the role of alpha5beta1 integrin in chondrocyte proliferation, we used agar suspension cultures in which the chondrocytes remain round in shape and their proliferative responses can be studied in the absence of possible changes in cell shape. Colony formation by chondrocytes in soft agar was inhibited by RGD peptides or antibodies (BIIG2 and 2A10) which interferes with beta1 integrin-ligand interactions. Strikingly, colony formation was stimulated by an antibody (U1alpha) which enhances the affinity of alpha5beta1 to fibronectin. Immunohistochemical analysis on tissue sections revealed that the alpha5 was particularly abundant in the proliferative and hypertrophic zones of growth plate. The results of the study indicate that alpha5beta1 integrin plays multiple roles in chondrocyte behavior and function, and appears to be involved in the regulation of chondrocyte-matrix interactions and proliferation.
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Research Products
(4 results)
