- Paper Report
- Open Access
A role for osteopontin in joint destruction
- Cheryl Smythe1
© Biomed Central Ltd 2002
- Received: 13 May 2002
- Accepted: 6 June 2002
- Published: 6 June 2002
Osteopontin (OPN) is an extracellular matrix protein that may play a role in inflammatory arthritis. OPN expression has been observed in the proliferating synovial cells and at the interface of cartilage and invading synovium of rheumatoid patients. In order to understand the contribution OPN makes to the pathology of rheumatoid arthritis (RA), the authors have investigated progression of anti-type II collagen antibody-induced arthritis in wild-type and OPN-deficient animals.
Immunohistological analysis demonstrated that OPN expression was enhanced in the superficial and deep layers of cartilage in arthritic mice. Cartilage destruction, chondrocyte apoptosis, proteoglycan depletion, joint swelling and infiltration of inflammatory cells into the knee joint were all significantly reduced in OPN-deficient arthritic mice compared to wild-type arthritic controls. By measuring the level of PECAM-1-positive cells in the synovia as an indicator of angiogenesis, an increased level of angiogenesis was observed in arthritis-induced wild-type mice which was not seen in OPN-deficient arthritic animals. Serum TNF levels following LPS treatment were identical in OPN-deficient and wild-type mice. Levels of urinary D-Pyr, a marker of bone resorption, were elevated in arthritic wild-type mice, but remained at basal levels in OPN-deficient arthritic animals.
- Yumoto K, Ishijima M, Rittling SR, Tsuji K, Tsuchiya Y, Kon S, Nifuji A, Uede T, Denhardt DT, Noda M: Osteopontin deficiency protects joints against destruction in anti-type II collagen antibody induced arthritis in mice. Proc Natl Acad Sci. 2002, 99: 4556-4561.PubMedPubMed CentralView ArticleGoogle Scholar