Dataset Information

Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints.

ABSTRACT: Osteoarthritis (OA) is one of most common skeletal disorders and can affect synovial joints such as knee and ankle joints. ?5 integrin, a major fibronectin receptor, is expressed in articular cartilage and has been demonstrated to play roles in synovial joint development and in the regulation of chondrocyte survival and matrix degradation in articular cartilage. We hypothesized that ?5 integrin signaling is involved in pathogenesis of OA. To test this, we generated compound mice that conditionally ablate ?5 integrin in the synovial joints using the Gdf5Cre system. The compound mice were born normally and had an overall appearance similar to the control mice. However, when the mutant mice received the OA surgery, they showed stronger resistance to osteoarthritic changes than the control. Specifically the mutant knee joints presented lower levels of cartilage matrix and structure loss and synovial changes and showed stronger biomechanical properties than the control knee joints. These findings indicate that ?5 integrin may not be essential for synovial joint development but play a causative role in induction of osteoarthritic changes.

SUBMITTER: Candela ME

PROVIDER: S-EPMC4900574 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints.

Candela Maria Elena ME Wang Chao C Gunawardena Aruni T AT Zhang Kairui K Cantley Leslie L Yasuhara Rika R Usami Yu Y Francois Noelle N Iwamoto Masahiro M van der Flier Arjan A Zhang Yejia Y Qin Ling L Han Lin L Enomoto-Iwamoto Motomi M

PloS one 20160609 6

Osteoarthritis (OA) is one of most common skeletal disorders and can affect synovial joints such as knee and ankle joints. α5 integrin, a major fibronectin receptor, is expressed in articular cartilage and has been demonstrated to play roles in synovial joint development and in the regulation of chondrocyte survival and matrix degradation in articular cartilage. We hypothesized that α5 integrin signaling is involved in pathogenesis of OA. To test this, we generated compound mice that conditional ...[more]

PMID: 27280771

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Project description:Articular cartilage needs sulfated-glycosaminoglycans (sGAGs) to withstand high pressures while mechanically loaded. Chondrocyte sGAG synthesis is regulated by exposure to compressive forces. Moderate physical exercise is known to improve cartilage sGAG content and might protect against osteoarthritis (OA). This study investigated whether rat knee joints with sGAG depleted articular cartilage through papain injections might benefit from moderate exercise, or whether this increases the susceptibility for cartilage degeneration.sGAGs were depleted from cartilage through intraarticular papain injections in the left knee joints of 40 Wistar rats; their contralateral joints served as healthy controls. Of the 40 rats included in the study, 20 rats remained sedentary, and the other 20 were subjected to a moderately intense running protocol. Animals were longitudinally monitored for 12 weeks with in vivo micro-computed tomography (?CT) to measure subchondral bone changes and single-photon emission computed tomography (SPECT)/CT to determine synovial macrophage activation. Articular cartilage was analyzed at 6 and 12 weeks with ex vivo contrast-enhanced ?CT and histology to measure sGAG content and cartilage thickness.All outcome measures were unaffected by moderate exercise in healthy control joints of running animals compared with healthy control joints of sedentary animals. Papain injections in sedentary animals resulted in severe sGAG-depleted cartilage, slight loss of subchondral cortical bone, increased macrophage activation, and osteophyte formation. In running animals, papain-induced sGAG-depleted cartilage showed increased cartilage matrix degradation, sclerotic bone formation, increased macrophage activation, and more osteophyte formation.Moderate exercise enhanced OA progression in papain-injected joints and did not protect against development of the disease. This was not restricted to more-extensive cartilage damage, but also resulted in pronounced subchondral sclerosis, synovial macrophage activation, and osteophyte formation.

Project description:Progressive loss of joint function in osteoarthritis (OA) is driven by degenerative and inflammatory processes and their complex interaction. Decoding the link between degeneration and inflammation is one of the most exciting approaches in understanding OA pathophysiology and holds the promise to open new therapeutic avenues. The overarching goal of this project was to analyze the impact of mononuclear cells (MNC) on enzymatic chondrodestructive processes (MMP/ADAMTS) in OA. Synovial membrane (SM), articular cartilage (AC) and peripheral blood (PB) were obtained from a total of 21 patients with advanced knee OA who underwent arthroplastic surgery. In supernatants of native synovial cell cultures, T cell-depleted synovial cell cultures and macrophage-depleted synovial cell cultures, the concentrations of various metalloproteinases were examined by Enzyme Linked Immunosorbent Assay (ELISA). Furthermore, ELISA was used to analyze concentrations of metalloproteinases in supernatants of chondrocyte monocultures and chondrocyte co-cultures with CD4+CD127dim/- enriched peripheral blood mononuclear cells (PBMC), Treg depleted CD4+CD25-CD127dim/- enriched PBMC and CD4+CD25+CD127dim/- Treg. Compared to native synovial cell culture, T cell depletion led to significantly lower levels of MMP1, MMP3 and MMP-9 and macrophage depletion led to a significant decline of MMP1, MMP3, MMP9 and ADAMTS-5 concentration. Compared to T cell depletion, macrophage depletion resulted in a significantly stronger reduction of MMP1, MMP3, MMP9 and ADAMTS5. In chondrocyte co-culture with CD4+CD127dim/- enriched PBMC the concentration of MMP1 and ADAMTS5 was significantly increased compared to chondrocyte monoculture. No significant differences were found between chondrocyte monoculture and chondrocyte coculture with Treg as well as between co-culture with CD4+CD127dim/- enriched PBMC containing Treg and co-culture with Treg-depleted CD4+CD25-CD127dim/- enriched PBMC. In conclusion, our data suggests that both synovial macrophages and T cells have a catabolic potential by inducing the release of chondrodestructive metalloproteinases in OA synovium. This study also supports the hypothesis that MNC affect the release of metalloproteinases by chondrocytes and are hereby involved in the cartilageinduced chondrodestructive process. In this study no suppressive effect of Treg was shown.

Project description:Natalizumab inhibits the transmigration of activated T lymphocytes into the brain and is highly efficacious in multiple sclerosis (MS). However, from a pharmacogenomic perspective, its efficacy and safety in specific patients remain unclear. Here our goal was to analyze the effects of epithelial V-like antigen (EVA) on anti-alpha? integrin (VLA4) efficacy in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). EVA has been previously characterized in human CD4 T lymphocytes, mouse thymic development, and choroid plexus epithelial cells. Further analysis here demonstrated expression in B lymphocytes and an increase in EVA? lymphocytes following immunization. Following active induction of EAE using the MOG³???? active immunization model, EVA deficient mice developed more severe EAE and white matter tissue injury as compared to wild type controls. This severe EAE phenotype did not respond to anti-VLA4 treatment. In both the control antibody and anti-VLA4 conditions, these mice demonstrated persistent CNS invasion of mature B lymphocyte (CD19?, CD21?, sIgG?), increased serum autoantibody levels, and extensive complement and IgG deposition within lesions containing CD5?IgG? cells. Wild type mice treated with control antibody also demonstrated the presence of CD19?, CD21?, sIgG? cells within the CNS during peak EAE disease severity and detectable serum autoantibody. In contrast, wild type mice treated with anti-VLA4 demonstrated reduced serum autoantibody levels as compared to wild type controls and EVA-knockout mice. As expected, anti-VLA4 treatment in wild type mice reduced the total numbers of all CNS mononuclear cells and markedly decreased CD4 T lymphocyte invasion. Treatment also reduced the frequency of CD19?, CD21?, sIgG? cells in the CNS. These results suggest that anti-VLA4 treatment may reduce B lymphocyte associated autoimmunity in some individuals and that EVA expression is necessary for an optimal therapeutic response. We postulate that these findings could optimize the selection of treatment responders.

Dataset Information

Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints.

Publications

Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints.

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