Volume 46, Issue 4 pp. 1094-1101
Original Article

Expression of osteopontin at sites of bone erosion in a murine experimental arthritis model of collagen-induced arthritis: Possible involvement of osteopontin in bone destruction in arthritis

Shiro Ohshima

Shiro Ohshima

Osaka University Medical School, Suita City, Osaka, Japan

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Hideyuki Kobayashi

Hideyuki Kobayashi

Osaka University Medical School, Suita City, Osaka, Japan

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Norihiko Yamaguchi

Norihiko Yamaguchi

Osaka University Medical School, Suita City, Osaka, Japan

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Katsuhiro Nishioka

Katsuhiro Nishioka

Osaka University Medical School, Suita City, Osaka, Japan

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Mitsuko Umeshita-Sasai

Mitsuko Umeshita-Sasai

Osaka University Medical School, Suita City, Osaka, Japan

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Toru Mima

Toru Mima

Osaka University Medical School, Suita City, Osaka, Japan

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Shintaro Nomura

Shintaro Nomura

Osaka University Medical School, Suita City, Osaka, Japan

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Shigeyuki Kon

Shigeyuki Kon

Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan, and Immuno-Biological Laboratories, Naka, Fujioka, Japan

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Manabu Inobe

Manabu Inobe

Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan

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Toshimitsu Uede

Toshimitsu Uede

Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan

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Yukihiko Saeki

Yukihiko Saeki

Osaka University Medical School, Suita City, Osaka, Japan

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First published: 05 April 2002
Citations: 50

Abstract

Objective

To investigate the involvement of osteopontin (OPN) in bone destruction in a murine experimental arthritis model of collagen-induced arthritis (CIA).

Methods

The expression of OPN was examined at both the messenger RNA (mRNA) and protein levels in various arthritic lesions in mice with CIA by in situ hybridization and immunohistochemistry, respectively. In addition, the expression of αvβ3 integrin, a receptor for OPN, the ligation of which is thought to be essential for bone resorption by osteoclasts, was examined by immunohistochemistry. Plasma concentrations of OPN were measured at different time points in the course of CIA by enzyme-linked immunosorbent assay.

Results

OPN mRNA was detected mainly at sites of bone erosion in arthritic lesions, where activated osteoclasts were present; OPN protein was also detected at sites of bone erosion. In the arthritic synovium, OPN was predominantly expressed in the synovial lining layer, but not in lymphoid aggregates. In addition, αvβ3 integrin was detected coincident with OPN at sites of bone erosion (bone–pannus junction). Plasma OPN levels were markedly elevated at the time points that corresponded to arthritis flares, and higher levels were maintained during the progression of arthritis.

Conclusion

OPN may mediate bone resorption by osteoclasts in arthritis through ligation with its receptor, αvβ3 integrin. OPN may be a useful therapeutic target molecule in the prevention of bone destruction in arthritis.

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