Regulation of joint destruction and inflammation by p53 in collagen-induced arthritis. (17/1192)

The role of the tumor suppressor p53 as a key regulator of inflammation was examined in murine collagen-induced arthritis (CIA), a model of rheumatoid arthritis. Wild-type DBA/1 mice develop progressive arthritis in this model, in which p53 expression and apoptosis are evident in the synovial cells. In contrast, the joints of p53(-/-) DBA/1 animals with CIA showed increased severity of arthritis using clinical and histological scoring methods with almost no apoptosis. Consistent with this, collagenase-3 expression and cytokine production (interleukin-1 and interleukin-6) in the joints of p53(-/-) mice with CIA were significantly greater than in wild-type mice. Anti-collagen antibody titers, however, were not different. Therefore, p53 expression occurs during inflammation and acts to suppress local inflammatory responses. Because mutations in p53 have been described in the synovial membrane of rheumatoid arthritis patients, the loss of p53 function in synoviocytes or other cells in the joint because of dominant-negative mutations might contribute to invasion and destruction of the joint in this disease.  (+info)

Effects of ageing and arthritic disease on nitric oxide production by human articular chondrocytes. (18/1192)

Nitric oxide (NO) has been considered as an important mediator in inflammatory phases and in loss of cartilage. In inflammatory arthritis, NO levels are correlated with disease activity and articular cartilage is able to produce large amounts of NO with the appropriate inducing factor such as cytokines. The old animals are shown to have a greater sensitivity to NO than young animals. This study evaluated the basal production of NO in normal and OA-affected chondroyctes from young and old patients and compared the levels of NO formation in response to IL-1beta. The results showed that the basal levels were 7-fold higher in old chondrocytes than those of young cells. However, the IL-1beta induced NO production was seen to decrease with age. Aminoguianidine (AG), a competitive inhibitor of iNOS, inhibited NO formation completely in both chondrocytes from young and old individuals. However, at the same concentration of AG it caused partial inhibition of NO and iNOS formation in chondrocytes from OA-affected individuals. In addition, although the IL-1beta induced NO production was much lesser than that of young chondrocytes, the inhibition of collagen production by IL-1beta was prominent in old chondrocytes and OA-affected chondrocytes. These results suggest that age-related differences in the regulation of NO production and collagen production, which may affect the ageing cells and osteoarthritic changes in some way.  (+info)

Expression of collagen and aggrecan genes in normal and osteoarthritic murine knee joints. (19/1192)

OBJECTIVE: The STR/ort mouse strain develops osteoarthritis (OA) of the medial tibial cartilage whilst CBA mice do not develop this disease. We investigated whether changes occur in the expression of genes encoding major extracellular matrix proteins in the connective tissue of the murine knee joint in OA. DESIGN: Expression of the genes encoding collagens II (Col2alpha1), X (Col10alpha1), alpha2(XI) (Col11alpha2) and aggrecan (Agc) was detected in skeletally mature and immature male mice of the CBA and STR/ort strains by in situ hybridization. RESULTS: Col2alpha1 was expressed by chondrocytes of the tibial and patella-femoral cartilage and by the meniscal cartilage in all young mice (4-9 weeks) but only in the patella-femoral cartilage in older mice of both strains (36-45 weeks). In contrast Col2alpha1 was expressed by growth plate chondrocytes of both species at all ages. Similarly, Col2alpha1 transcripts were detected in cruciate ligament cells in both strains at all ages. Col10alpha1 transcripts were detected in cruciate ligament cells in both strains at all ages. Col10alpha1 expression was evident in the hypertrophic chondrocytes in the growth plate of young CBA and STR mice, but was not active in these cells in mature animals. However, Col10alpha1 was transcribed in articular chondrocytes of the tibia, meniscal and patella-femoral cartilages of all ages, in normal and osteoarthritic mice. Transcripts were also present in ligament of some mature animals. Col11alpha2 followed a similar pattern of expression in CBA cartilages to Col2alpha1, being active in adult growth plate but generally inactive in adult articular cartilages. Young CBA and STR/ort mice expressed Col11alpha2 in articular cartilage and very strongly throughout the growth plate. Agc expression was detected in all articular cartilages at all ages in both strains. Interestingly, transcripts for all four genes were absent in tibial articular chondrocytes located close to osteoarthritic lesions in STR/ort mice, indicating that these cells are unable to synthesize matrix proteins. Adult STR/ort mice also showed evidence of tissue remodeling around the periphery of the knee joint. Cells in remodeling areas actively transcribed Col2alpha1, Col10alpha1, Col11alpha2 and Agc. CONCLUSION: It is unlikely that OA develops in STR/ort mice because of failure to express major proteins in joint tissue. However, once lesions develop in articular cartilage neighbouring chondrocytes fail to express genes encoding several matrix proteins.  (+info)

Dedifferentiation-associated changes in morphology and gene expression in primary human articular chondrocytes in cell culture. (20/1192)

OBJECTIVE: The aim of the present study was the investigation of differential gene expression in primary human articular chondrocytes (HACs) and in cultivated cells derived from HACs. DESIGN: Primary human articular chondrocytes (HACs) isolated from non-arthritic human articular cartilage and monolayer cultures of HACs were investigated by immunohistochemistry, Northern analysis, RT-PCR and cDNA arrays. RESULTS: By immunohistochemistry we detected expression of collagen II, protein S-100, chondroitin-4-sulphate and vimentin in freshly isolated HACs. Cultivated HACs, however, showed only collagen I and vimentin expression. These data were corroborated by the results of Northern analysis using specifc cDNA probes for collagens I, II and III and chondromodulin, respectively, demonstrating collagen II and chondromodulin expression in primary HACs but not in cultivated cells. Hybridization of mRNA from primary HACs and cultivated cells to cDNA arrays revealed additional transcriptional changes associated with dedifferentiation during propagation of chondrocytes in vitro. We found a more complex hybridization pattern for primary HACs than for cultivated cells. Of the genes expressed in primary HACs the early growth response (EGR1) transcription factor showed the strongest expression whereas D-type cyclin was expressed in proliferating cells. Other factors associated with differentiated HACs were the adhesion molecules ICAM-1 and VCAM-1, VEGF, TGFbeta2, and the monocyte chemotactic protein receptor. CONCLUSIONS: Our data support the hypothesis that HACs dedifferentiate when grown in monolayer cultures. Moreover, the expression patterns also show that proliferation and differentiation are exclusive features of human chondrocytes.  (+info)

Potent antiarthritic properties of a glucocorticoid derivative, NCX-1015, in an experimental model of arthritis. (21/1192)

Here, we describe the improved antiarthritic properties of a nitric oxide-releasing derivative of prednisolone that includes a sparing of the effects on bone. Glucocorticoids are widely used in the treatment of chronic inflammatory pathologies, but their use is often accompanied by side effects, including osteoporosis. Recently, a new steroid able to release low levels of nitric oxide showed potent inhibition of leukocyte trafficking and chemokine generation in models of acute inflammation. The objective of this study was to assess the anti-inflammatory activity of this nitric-oxide releasing glucocorticoid, nitro-prednisolone (NCX-1015), in parallel with the parent compound prednisolone and a control molecule lacking an NO group, (NCX-1016), in a model of rat collagen-induced arthritis. Dosing of rats with NCX-1015 (0.4-4 micromol/kg, i.p.) greatly reduced all parameters of inflammation. A significant but inferior anti-inflammatory effect also was obtained with prednisolone. Collagen-induced arthritic rats had elevated pyridinoline values (> 60% over naive rats), indicating bone and cartilage erosion; this increase was prevented by NCX-1015 but not by prednisolone or NCX-1016 treatment. In vitro, prednisolone (1 nM), but not NCX-1015, elevated bone resorbing activity of rat primary osteoclasts. In conclusion, NCX-1015 is a steroid derivative with a potential for the treatment of chronic inflammatory pathologies and that has milder side effects anticipated on the bone compartment.  (+info)

A fibronectin fragment induces type II collagen degradation by collagenase through an interleukin-1-mediated pathway. (22/1192)

OBJECTIVE: To examine the effects of a fibronectin (FN) fragment containing the COOH-terminal heparin-binding domain (HBFN-f) on chondrocyte-mediated type II collagen (CII) cleavage by collagenase and proteoglycan (PG) degradation in articular cartilage in explant culture. METHODS: Intact FN or HBFN-f was added to explant cultures of mature bovine articular cartilage. We investigated collagenase-mediated cleavage of CII caused by HBFN-f in explant cultures using a new immunoassay for detection and measurement of the primary collagenase cleavage site of CII. CII denaturation in cartilage was also measured using a specific enzyme-linked immunosorbent assay. Degradation of PG (principally aggrecan) was analyzed by a dye-binding assay. APMA and/or a matrix metalloproteinase 13 (MMP-13) preferential inhibitor or interleukin-1 receptor antagonist (IL-1Ra) were added to some cultures to examine the presence of latent procollagenase or the involvement of MMP-13 or IL-1, respectively, in cartilage breakdown induced by HBFN-f. Secretion of MMP-3 and MMP-13 into media was detected by immunoblotting. RESULTS: In contrast to intact FN, HBFN-f was shown to stimulate CII cleavage by collagenase in a dose-dependent manner following PG degradation, similar to cartilage breakdown induced by IL-1. Treatment with HBFN-f also resulted in elevated denaturation of CII. Immunoblotting demonstrated that HBFN-f enhanced pro-matrix metalloproteinase 13 (proMMP-13) production as well as that of proMMP-3. APMA, which activates latent proMMPs, enhanced the HBFN-f-mediated cleavage of CII by collagenase. An MMP-13 preferential inhibitor or IL-1Ra suppressed HBFN-f-induced collagen cleavage to control levels. CONCLUSION: Our data demonstrate that HBFN-f can induce early PG degradation and subsequent CII cleavage. The latter is probably mediated by early proMMP-13 induction involving an IL-1-dependent pathway. Activation of latent collagenase is delayed. This new information, together with existing data on other FN fragments, reveals that increased levels of these fragments, found in diseased joints such as in osteoarthritis and rheumatoid arthritis, may stimulate cartilage breakdown by mechanisms of the kind demonstrated in the present study.  (+info)

Association of baseline levels of urinary glucosyl-galactosyl-pyridinoline and type II collagen C-telopeptide with progression of joint destruction in patients with early rheumatoid arthritis. (23/1192)

OBJECTIVE: To evaluate whether measurements of urinary glucosyl-galactosyl-pyridinoline (Glc-Gal-PYD) and urinary C-terminal crosslinking telopeptide of type II collagen (CTX-II), 2 new markers of destruction of the synovium and cartilage collagen breakdown, respectively, are associated with the progression of joint damage in patients with early rheumatoid arthritis (RA), and to compare this association with that with serum matrix metalloproteinase 3 (MMP-3), a proteinase expressed by synovial tissue and chondrocytes, and that with serum C-reactive protein (CRP), an index of systemic inflammation. METHODS: The prospective study cohort comprised 116 patients with early RA who were part of a large, double-blind, randomized study comparing the efficacy of etanercept and methotrexate. The relationship between baseline levels of urinary Glc-Gal-PYD, urinary CTX-II, and serum MMP-3 and the progression of joint destruction, as measured by changes in the modified Sharp score (average findings of 2 independent readers) over 1 year, was investigated. RESULTS: Levels of urinary Glc-Gal-PYD (+70%), urinary CTX-II (+104%), and serum MMP-3 (+219%) were elevated compared with the levels in 76 healthy controls. The baseline levels of Glc-Gal-PYD (r = 0.30), CTX-II (r = 0.25), and MMP-3 (r = 0.29) correlated with the changes over 1 year in the total Sharp score (joint space narrowing and bone erosion). Patients with baseline levels of Glc-Gal-PYD, CTX-II, and MMP-3 that were higher than the mean + 2 SD in healthy controls had a significantly greater progression of joint damage, with an increase in the total Sharp score over 1 year that was from 3- to 8-fold higher than that in patients with low baseline levels of these markers. Moreover, patients with these higher levels of Glc-Gal-PYD, CTX-II, and MMP-3 had a higher risk of progression of the disease (increase in total Sharp score > or =0.5 units) than did the other patients (relative risks and 95% confidence intervals [95% CI] 3.3 [95% CI 1.5-7.4], 2.5 [95% CI 1.1-5.7], and 2.5 [95% CI 1.1-5.6], respectively). The baseline serum level of CRP was not significantly associated with the progression of joint damage. Adjustment of the levels of Glc-Gal-PYD, CTX-II, and MMP-3 according to radiologic damage at baseline did not alter their association with progression. After adjustment for serum CRP, the relative risk slightly decreased, but remained significant, for Glc-Gal-PYD (2.6 [95% CI 1.1-6.3]). Patients with both increased levels of the molecular markers and radiologic damage at baseline had a higher risk of progression of joint damage than did those with either high molecular marker levels or radiologic damage. CONCLUSION: High baseline levels of Glc-Gal-PYD, CTX-II, and MMP-3 are associated with increased risk of progression of joint destruction over 1 year in early RA. The association between baseline levels of urinary Glc-Gal-PYD and progression of joint erosion was independent of the severity of radiologic damage and inflammation at baseline. Combining the measurements of these molecular markers with radiologic assessment of joint damage may be useful for identifying patients with RA who are at high risk of rapid progression and for whom early aggressive treatment would be beneficial.  (+info)

Identification of type II collagen peptide 261-273-specific T cell clones in a patient with relapsing polychondritis. (24/1192)

OBJECTIVE: To characterize and clone T cells specific for type II collagen (CII) in a patient with relapsing polychondritis (RP) and to establish whether the immunodominant epitope of CII determined in HLA transgenic mice is used in the human autoimmune response to CII. METHODS: T cell responses to CII were examined in a patient with RP, who was heterozygous for the HLA-DR allele DRB1*0101/DRB1*0401. T cell clones were established from this patient and characterized for peptide specificity, class II restriction, cytokine production, and staining with HLA-DRB1*0401 class II tetramers. RESULTS: A response to CII and the peptide 255-273 was present in this patient. T cells specific for the CII epitope 261-273 were cloned. Evaluation of these clones demonstrated a response to CII 261-273 in the context of both DR alleles. HLA-DR4 CII tetramer did not demonstrate staining of either CII-specific DRB1*0401-restricted T cell clones or a polyclonal population of CII-reactive T cells from this individual. CONCLUSION: T cells directed against CII were present in this patient with RP. Also, T cell clones isolated from this individual were found to be specific for the CII peptide 261-273 and were restricted to either the DRB1*0101 or the DRB1*0401 allele. These findings establish that a T cell response directed against CII is present in this patient with RP and that the CII peptide 261-273 plays a role in the human immune response to CII.  (+info)