Cartilage Destruction (cartilage + destruction)

Distribution by Scientific Domains

Selected Abstracts

Addition of bisphosphonate to antibiotic and anti-inflammatory treatment reduces bone resorption in experimental Staphylococcus aureus -induced arthritis

Margareta Verdrengh
Abstract Bacterial arthritis is a disease with high morbidity leading to rapidly progressive bone resorption. We have shown earlier that treatment with antibiotics in combination with corticosteroids decreases joint inflammation and mortality but does not significantly affect bone/cartilage destruction of the joints. This study was performed to assess the effect of treatment with bisphosphonate [zoledronic acid (ZA)] in combination with antibiotics and corticosteroids, on the course and outcome of Staphlococcus aureus -induced arthritis. Three days after intravenous inoculation with S. aureus, mice were treated with antibiotics alone, ZA alone, ZA and antibiotics, or ZA combined with antibiotics and corticosteroids, respectively. One group served as controls and received PBS. Clinical assessment of arthritis was performed as well as histological analysis of bone and cartilage destruction in the joints. One femur from each mouse was collected for bone mineral density (BMD) analysis. In addition, serum levels of type I collagen fragments (RatLaps), and osteocalcin, markers for osteoclastic and osteoblastic activity, respectively, were analyzed. Mice treated with ZA and antibiotics or with ZA in combination with antibiotics and corticosteroids lost significantly less in trabecular bone density compared to infected control mice. Furthermore, the addition of corticosteroids to animals treated with ZA and antibiotics, significantly decreased serum levels of RatLaps and osteocalcin, compared to animals treated with ZA and antibiotics or ZA alone. Treatment with bisphosphonates in combination with antimicrobial agents and corticosteroids significantly decreases the activity of osteoclasts in septic arthritis, thereby reducing the risk of skeletal destruction. 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]

Beneficial effect of galectin 9 on rheumatoid arthritis by induction of apoptosis of synovial fibroblasts

Masako Seki
Objective To compare the expression of galectin 9 (Gal-9) in synovial tissue (ST) from rheumatoid arthritis (RA) patients and osteoarthritis (OA) patients and to evaluate the effects of Gal-9 on fibroblast-like synoviocytes (FLS) in these patients. Methods The expression of Gal-9 in ST and FLS was compared using immunohistochemical techniques. Apoptotic cells in RA and OA ST samples were detected by TUNEL assay. Apoptosis of FLS was analyzed by the sub-G1 method in vitro. The in vivo suppressive effects of Gal-9 on collagen-induced arthritis (CIA) in a mouse model were also elucidated. Results The percentage of Gal-9,positive cells in ST samples and the amount of Gal-9 in synovial fluid samples were significantly higher in patients with RA than in patients with OA, suggesting the involvement of Gal-9 in the development of RA. Compared with the 2 wild-type Gal-9 forms, stable Gal-9, a mutant protein resistant to proteolysis, significantly induced apoptosis of FLS from RA patients. In contrast, other galectins, such as Gal-1, Gal-3, and Gal-8, did not induce apoptosis or suppress the proliferation of human RA FLS. Stable Gal-9 preferentially induced apoptosis and suppressed the proliferation of RA FLS in vitro. It also induced apoptosis of cells in RA ST implanted into SCID mice in vivo. In a mouse model of CIA, apoptotic cells were detected in the joints of stable Gal-9,treated mice, but not phosphate buffered saline,treated mice, and suppressed CIA characterized by pannus formation with inflammatory cell infiltration and bone/cartilage destruction. Conclusion Gal-9,induced apoptosis of hyperproliferative RA FLS may play a critical role in the suppression of RA. [source]

N -acetylcysteine prevents nitric oxide-induced chondrocyte apoptosis and cartilage degeneration in an experimental model of osteoarthritis

Shuji Nakagawa
Abstract We investigated whether N -acetylcysteine (NAC), a precursor of glutathione, could protect rabbit articular chondrocytes against nitric oxide (NO)-induced apoptosis and could prevent cartilage destruction in an experimental model of osteoarthritis (OA) in rats. Isolated chondrocytes were treated with various concentrations of NAC (0,2 mM). Apoptosis was induced by 0.75 mM sodium nitroprusside (SNP) dehydrate, which produces NO. Cell viability was assessed by MTT assay, while apoptosis was evaluated by Hoechst 33342 and TUNEL staining. Intracellular reactive oxygen species (ROS) and glutathione levels were measured, and expression of p53 and caspase-3 were determined by Western blotting. To determine whether intraarticular injection of NAC prevents cartilage destruction in vivo, cartilage samples of an OA model were subjected to H&E, Safranin O, and TUNEL staining. NAC prevented NO-induced apoptosis, ROS overproduction, p53 up-regulation, and caspase-3 activation. The protective effects of NAC were significantly blocked by buthionine sulfoximine, a glutathione synthetase inhibitor, indicating that the apoptosis-preventing activity of NAC was mediated by glutathione. Using a rat model of experimentally induced OA, we found that NAC also significantly prevented cartilage destruction and chondrocyte apoptosis in vivo. These results indicate that NAC inhibits NO-induced apoptosis of chondrocytes through glutathione in vitro, and inhibits chondrocyte apoptosis and articular cartilage degeneration in vivo. 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:156,163, 2010 [source]

Addition of bisphosphonate to antibiotic and anti-inflammatory treatment reduces bone resorption in experimental Staphylococcus aureus -induced arthritis

Margareta Verdrengh
Abstract Bacterial arthritis is a disease with high morbidity leading to rapidly progressive bone resorption. We have shown earlier that treatment with antibiotics in combination with corticosteroids decreases joint inflammation and mortality but does not significantly affect bone/cartilage destruction of the joints. This study was performed to assess the effect of treatment with bisphosphonate [zoledronic acid (ZA)] in combination with antibiotics and corticosteroids, on the course and outcome of Staphlococcus aureus -induced arthritis. Three days after intravenous inoculation with S. aureus, mice were treated with antibiotics alone, ZA alone, ZA and antibiotics, or ZA combined with antibiotics and corticosteroids, respectively. One group served as controls and received PBS. Clinical assessment of arthritis was performed as well as histological analysis of bone and cartilage destruction in the joints. One femur from each mouse was collected for bone mineral density (BMD) analysis. In addition, serum levels of type I collagen fragments (RatLaps), and osteocalcin, markers for osteoclastic and osteoblastic activity, respectively, were analyzed. Mice treated with ZA and antibiotics or with ZA in combination with antibiotics and corticosteroids lost significantly less in trabecular bone density compared to infected control mice. Furthermore, the addition of corticosteroids to animals treated with ZA and antibiotics, significantly decreased serum levels of RatLaps and osteocalcin, compared to animals treated with ZA and antibiotics or ZA alone. Treatment with bisphosphonates in combination with antimicrobial agents and corticosteroids significantly decreases the activity of osteoclasts in septic arthritis, thereby reducing the risk of skeletal destruction. 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]

In vivo high-resolution synchrotron radiation imaging of collagen-induced arthritis in a rodent model

Chang-Hyuk Choi
In vivo microstructures of the affected feet of collagen-induced arthritic (CIA) mice were examined using a high-resolution synchrotron radiation (SR) X-ray refraction technique with a polychromatic beam issued from a bending magnet. The CIA models were obtained from six-week-old DBA/1J mice that were immunized with bovine type II collagen and grouped as grades 0,3 according to a clinical scoring for the severity of arthritis. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens before being captured with a digital charge-coupled-device camera. Various changes in the joint microstructure, including cartilage destruction, periosteal born formation, articular bone thinning and erosion, marrow invasion by pannus progression, and widening joint space, were clearly identified at each level of arthritis severity with an equivalent pixel size of 2.7,m. These high-resolution features of destruction in the CIA models have not previously been available from any other conventional imaging modalities except histological light microscopy. However, thickening of the synovial membrane was not resolved in composite images by the SR refraction imaging method. In conclusion, in vivo SR X-ray microscopic imaging may have potential as a diagnostic tool in small animals that does not require a histochemical preparation stage in examining microstructural changes in joints affected with arthritis. The findings from the SR images are comparable with standard histopathology findings. [source]

Mammalian target of rapamycin signaling is crucial for joint destruction in experimental arthritis and is activated in osteoclasts from patients with rheumatoid arthritis

Daniel Cejka
Objective Activation of the mammalian target of rapamycin (mTOR) pathway is important for immune cell activation and bone metabolism. To date, the contribution of mTOR signaling to joint inflammation and structural bone and cartilage damage is unknown. The aim of this study was to investigate the potential of inhibiting mTOR as a treatment of inflammatory arthritis. Methods Human tumor necrosis factor,transgenic mice in which inflammatory arthritis was developing were treated with 2 different mTOR inhibitors, sirolimus or everolimus. The effects of treatment on clinical disease activity, inflammation, and localized joint and cartilage destruction were studied. In addition, the effects of mTOR inhibition on osteoclast survival and expression of key molecules of osteoclast function were analyzed in vitro. Moreover, synovial tissue from patients with rheumatoid arthritis (RA) was assessed for activation of the mTOR pathway. Results Inhibition of mTOR by sirolimus or everolimus reduced synovial osteoclast formation and protected against local bone erosions and cartilage loss. Clinical signs of arthritis improved after mTOR inhibition, and histologic evaluation showed a decrease in synovitis. In vitro, mTOR inhibition down-regulated the expression of digestive enzymes and led to osteoclast apoptosis. Moreover, mTOR signaling was shown to be active in the synovial membrane of patients with RA, particularly in synovial osteoclasts. Conclusion Signaling through mTOR is an important link between synovitis and structural damage in inflammatory arthritis. Current pharmacologic inhibitors of mTOR could be effective in protecting joints against structural damage. [source]

Matriptase is a novel initiator of cartilage matrix degradation in osteoarthritis

Jennifer M. Milner
Objective Increasing evidence implicates serine proteinases in pathologic tissue turnover. The aim of this study was to assess the role of the transmembrane serine proteinase matriptase in cartilage destruction in osteoarthritis (OA). Methods Serine proteinase gene expression in femoral head cartilage obtained from either patients with hip OA or patients with fracture to the neck of the femur (NOF) was assessed using a low-density array. The effect of matriptase on collagen breakdown was determined in cartilage degradation models, while the effect on matrix metalloproteinase (MMP) expression was analyzed by real-time polymerase chain reaction. ProMMP processing was determined using sodium dodecyl sulfate,polyacrylamide gel electrophoresis/N-terminal sequencing, while its ability to activate proteinase-activated receptor 2 (PAR-2) was determined using a synovial perfusion assay in mice. Results Matriptase gene expression was significantly elevated in OA cartilage compared with NOF cartilage, and matriptase was immunolocalized to OA chondrocytes. We showed that matriptase activated proMMP-1 and processed proMMP-3 to its fully active form. Exogenous matriptase significantly enhanced cytokine-stimulated cartilage collagenolysis, while matriptase alone caused significant collagenolysis from OA cartilage, which was metalloproteinase-dependent. Matriptase also induced MMP-1, MMP-3, and MMP-13 gene expression. Synovial perfusion data confirmed that matriptase activates PAR-2, and we demonstrated that matriptase-dependent enhancement of collagenolysis from OA cartilage is blocked by PAR-2 inhibition. Conclusion Elevated matriptase expression in OA and the ability of matriptase to activate selective proMMPs as well as induce collagenase expression make this serine proteinase a key initiator and inducer of cartilage destruction in OA. We propose that the indirect effects of matriptase are mediated by PAR-2, and a more detailed understanding of these mechanisms may highlight important new therapeutic targets for OA treatment. [source]

META060 inhibits osteoclastogenesis and matrix metalloproteinases in vitro and reduces bone and cartilage degradation in a mouse model of rheumatoid arthritis

Veera Reddy Konda
Objective The multikinase inhibitor META060 has been shown to inhibit NF-,B activation and expression of markers of inflammation. This study was undertaken to investigate the effect of META060 on biomarkers associated with bone and cartilage degradation in vitro and its antiinflammatory efficacy in vivo in both acute and chronic inflammation models. Methods Glycogen synthase kinase 3, (GSK3,),dependent ,-catenin phosphorylation was evaluated in RAW 264.7 macrophages to assess kinase inhibition. The inhibition of osteoclastogenesis and tartrate-resistant acid phosphatase (TRAP) activity was evaluated in RANKL-treated RAW 264.7 cells. The inhibition of interleukin-1, (IL-1,),mediated markers of inflammation was analyzed in human rheumatoid arthritis synovial fibroblasts (RASFs). Mice with carrageenan-induced acute inflammation and collagen-induced arthritis (CIA) were used to assess efficacy. Results META060 inhibited the activity of kinases (spleen tyrosine kinase [Syk], Bruton's tyrosine kinase [Btk], phosphatidylinositol 3-kinase [PI 3-kinase], and GSK3) associated with RA and inhibited ,-catenin phosphorylation. META060 inhibited osteoclastogenesis, as indicated by decreased transformation of RAW 264.7 cells to osteoclasts and reduced TRAP activity, and inhibited IL-1,,activated prostaglandin E2, matrix metalloproteinase 3, IL-6, IL-8, and monocyte chemotactic protein 1 in RASFs. In mice with acute inflammation, oral administration of META060 reduced paw swelling similar to the effect of aspirin. In mice with CIA, META060 significantly reduced the arthritis index and decreased bone, joint, and cartilage degradation. Serum IL-6 concentrations in these mice were inhibited in a dose-dependent manner. Conclusion Our findings indicate that META060 reduces swelling in a model of acute inflammation and inhibits bone and cartilage destruction in a model of chronic inflammation. Its efficacy is associated with the inhibition of multiple protein kinases, including Syk, Btk, PI 3-kinase, and GSK3. These results warrant further clinical testing of META060 for its therapeutic potential in the treatment of inflammatory diseases. [source]

Control of Dkk-1 ameliorates chondrocyte apoptosis, cartilage destruction, and subchondral bone deterioration in osteoarthritic knees

Lin-Hsiu Weng
Objective Perturbation of Wnt signaling components reportedly regulates chondrocyte fate and joint disorders. The Wnt inhibitor Dkk-1 mediates remodeling of various tissue types. We undertook this study to examine whether control of Dkk-1 expression prevents joint deterioration in osteoarthritic (OA) knees. Methods Anterior cruciate ligament transection,and collagenase-induced OA in rat knees was treated with end-capped phosphorothioate Dkk-1 antisense oligonucleotide (Dkk-1,AS). Articular cartilage destruction, cartilage degradation markers, bone mineral density (BMD), and subchondral trabecular bone volume of injured knee joints were measured using Mankin scoring, enzyme-linked immunosorbent assay, dual x-ray absorptiometry, and histomorphometry. Dkk-1,responsive molecule expression and apoptotic cells in knee tissue were detected by quantitative reverse transcriptase,polymerase chain reaction, immunoblotting, and TUNEL staining. Results Up-regulated Dkk-1 expression was associated with increased Mankin score and with increased serum levels of cartilage oligomeric matrix protein and C-telopeptide of type II collagen (CTX-II) during OA development. Dkk-1,AS treatment alleviated OA-associated increases in Dkk-1 expression, Mankin score, cartilage fibrillation, and serum cartilage degradation markers. Dkk-1,AS also alleviated epiphyseal BMD loss and subchondral bone exposure associated with altered serum levels of osteocalcin and CTX-I. The treatment abrogated chondrocyte/osteoblast apoptosis and subchondral trabecular bone remodeling in OA. Dkk-1 knockdown increased levels of nuclear ,-catenin and phosphorylated Ser473 -Akt but attenuated expression of inflammatory factors (Toll-like receptor 4 [TLR-4], TLR-9, interleukin-1,, and tumor necrosis factor ,), the apoptosis regulator Bax, matrix metalloproteinase 3, and RANKL in OA knee joints. Conclusion Interference with the cartilage- and bone-deleterious actions of Dkk-1 provides therapeutic potential for alleviating cartilage destruction and subchondral bone damage in OA knee joints. [source]

Comparative analysis of gene expression profiles between primary knee osteoarthritis and an osteoarthritis endemic to Northwestern China, Kashin-Beck disease

Chen Duan
Objective To investigate the differences in gene expression profiles of adult articular cartilage from patients with Kashin-Beck disease (KBD) versus those with primary knee osteoarthritis (OA). Methods The messenger RNA expression profiles of articular cartilage from patients with KBD, diagnosed according to the clinical criteria for KBD in China, were compared with those of cartilage from patients with OA, diagnosed according to the Western Ontario and McMaster Universities OA Index. Total RNA was isolated separately from 4 pairs of the KBD and OA cartilage samples, and the expression profiles were evaluated by Agilent 444k Whole Human Genome density oligonucleotide microarray analysis. The microarray data for selected transcripts were confirmed by quantitative real-time reverse transcription,polymerase chain reaction (RT-PCR) amplification. Results For 1.2 104 transcripts, corresponding to 58.4% of the expressed transcripts, 2-fold changes in differential expression were revealed. Expression levels higher in KBD than in OA samples were observed in a mean SD 6,439 1,041 (14.6 2.4%) of the transcripts, and expression levels were lower in KBD than in OA samples in 6,147 1,222 (14.2 2.8%) of the transcripts. After application of the selection criteria, 1.85% of the differentially expressed genes (P < 0.001 between groups) were detected. These included 233 genes, of which 195 (0.4%) were expressed at higher levels and 38 (0.08%) were expressed at lower levels in KBD than in OA cartilage. Comparisons of the quantitative RT-PCR data supported the validity of our microarray data. Conclusion Differences between KBD and OA cartilage exhibited a similar pattern among all 4 of the pairs examined, indicating the presence of disease mechanisms, mainly chondrocyte matrix metabolism, cartilage degeneration, and apoptosis induction pathways, which contribute to cartilage destruction in KBD. [source]

Inflammatory arthritis in caspase 1 gene,deficient mice: Contribution of proteinase 3 to caspase 1,independent production of bioactive interleukin-1,

Leo A. B. Joosten
Objective Caspase 1, a known cysteine protease, is a critical component of the inflammasome. Both caspase 1 and neutrophil serine proteases such as proteinase 3 (PR3) can process pro,interleukin-1, (proIL-1,), a crucial cytokine linked to the pathogenesis of rheumatoid arthritis. This study was undertaken to establish the relative importance of caspase 1 and serine proteases in mouse models of acute and chronic inflammatory arthritis. Methods Acute and chronic arthritis were induced in caspase 1,/, mice, and the lack of caspase 1 was investigated for its effects on joint swelling, cartilage metabolism, and histopathologic features. In addition, caspase 1 activity was inhibited in mice lacking active cysteine proteases, and the effects of dual blockade of caspase 1 and serine proteases on arthritis severity and histopathologic features were evaluated. Results Surprisingly, caspase 1,/, mice, in a model of acute (neutrophil-dominated) arthritis, developed joint swelling to an extent similar to that in wild-type control mice. Joint fluid concentrations of bioactive IL-1, were comparable in caspase 1,/, mice and controls. In contrast, induction of chronic arthritis (characterized by minimal numbers of neutrophils) in caspase 1,/, mice led to reduced joint inflammation and less cartilage damage, implying a caspase 1,dependent role in this process. In mice lacking neutrophil serine PR3, inhibition of caspase 1 activity resulted in decreased bioactive IL-1, concentrations in the synovial tissue and less suppression of chondrocyte anabolic function. In addition, dual blockade of both PR3 and caspase 1 led to protection against cartilage and bone destruction. Conclusion Caspase 1 deficiency does not affect neutrophil-dominated joint inflammation, whereas in chronic arthritis, the lack of caspase 1 results in reduced joint inflammation and cartilage destruction. These findings suggest that inhibitors of caspase 1 are not able to interfere with the whole spectrum of IL-1, production, and therefore such inhibitors may be of therapeutic value only in inflammatory conditions in which limited numbers of neutrophils are present. [source]

Scavenger receptor class A type I/II determines matrix metalloproteinase,mediated cartilage destruction and chondrocyte death in antigen-induced arthritis

P. L. E. M. van Lent
Objective Scavenger receptor class A type I (SR-AI) and SR-AII are expressed by macrophages in particular and bind and internalize a broad range of molecules (including endotoxins, apoptotic bodies, and oxidized low-density lipoprotein). This study was undertaken to investigate the role of SR-AI/II in mediating severe cartilage destruction in antigen-induced arthritis (AIA). Methods AIA was induced in the knee joints of SR-AI/II,/, mice and wild-type (WT) controls. Joint inflammation and cartilage destruction (chondrocyte death) were measured by examining the histology of total knee joints. Matrix metalloproteinase (MMP),mediated neoepitopes were measured by immunolocalization using anti-VDIPEN antibodies and chondrocyte activation with anti-S100A8 antibodies. Messenger RNA (mRNA) levels were determined in inflamed synovium using microarray analysis and quantitative reverse transcriptase,polymerase chain reaction. In synovial washouts, cytokines (interleukin-1, [IL-1,], IL-10, and tumor necrosis factor ,) and S100A8/S100A9 were measured using Luminex and enzyme-linked immunosorbent assay. Results Levels of SR-AI/II mRNA were strongly elevated in inflamed synovium in AIA. On days 2, 8, and 14 after AIA induction, joint inflammation (exudates/infiltrate) was similar between the 2 groups. In WT mice, severe cartilage destruction was found in multiple cartilage surfaces of the inflamed knee joint on day 14 after AIA induction. MMP-mediated matrix destruction ranged between 40% and 60%, and chondrocyte death was prominent in 40,75% of the cartilage surfaces. In striking contrast, in SR-AI/II,/, mice, despite comparable joint inflammation, pronounced cartilage destruction was almost completely absent. Levels of IL-1, and S100A8/S100A9 were significantly lower on days 7 and 14 after AIA induction, but levels of mRNA for various MMPs (MMP-2, MMP-3, MMP-9, and MMP-13) were comparable. Conclusion Our findings indicate that SR-AI and SR-AII are crucial receptors involved in mediating severe cartilage destruction in AIA. [source]

Liver X receptor agonism promotes articular inflammation in murine collagen-induced arthritis

Darren L. Asquith
Objective Liver X receptors (LXRs) have previously been implicated in the regulation of inflammation and have, in general, been ascribed an antiinflammatory role. This study was therefore undertaken to explore the biologic mechanisms of LXRs in vivo and in vitro in an experimental inflammatory arthritis model. Methods Male DBA/1 mice were immunized with type II collagen and treated from an early or established stage of arthritis with 2 different concentrations of the LXR agonists T1317 and GW3965 or vehicle control. The mice were monitored for articular inflammation and cartilage degradation by scoring for clinical signs of arthritis, histologic examination of the joints, and analysis of serum cytokine and antibody levels. In vitro, primary human monocytes and T cells were cultured in the presence of GW3965 or T1317, and the concentrations of proinflammatory cytokines were measured by multiplex assay. Results Contrary to expectations, LXR agonism with the use of 2 discrete, specific molecular entities led to substantial exacerbation of articular inflammation and cartilage destruction in this murine collagen-induced arthritis model. This was associated ex vivo with elevated cytokine expression, with enhanced Th1 and Th17 cellular responses, and with elevated collagen-specific autoantibody production. In vitro, LXR agonists, in concert with lipopolysaccharide, promoted cytokine and chemokine release from human monocytes, and similar effects were observed in a T cell,macrophage coculture model that closely recapitulates the pathways that drive synovial cytokine release. Conclusion Since LXRs are present in rheumatoid arthritis (RA) synovium, these results suggest that LXR-mediated pathways could exacerbate the chronic inflammatory response typical of RA. [source]

Role of Wnt-5A in interleukin-1,,induced matrix metalloproteinase expression in rabbit temporomandibular joint condylar chondrocytes

Xianpeng Ge
Objective To determine the possible involvement and regulatory mechanisms of Wnt-5A signaling in interleukin-1, (IL-1,),induced increase in matrix metalloproteinase 1 (MMP-1), MMP-3, MMP-9, and MMP-13 expression in temporomandibular joint (TMJ) condylar chondrocytes. Methods Primary rabbit condylar chondrocytes were treated with IL-1,, purified Wnt-5A protein, or both and transfected with Wnt-5A expression vector. Expression of Wnt-5A, MMP-1, MMP-3, MMP-9, MMP-13, and type II collagen, as well as cell morphologic changes, were examined. To explore the mechanisms of action of Wnt-5A, the accumulation and nuclear translocation of ,-catenin, the transcription activity of the ,-catenin,Tcf/Lef complex, phosphorylated JNK, phosphorylated ERK, and phosphorylated p38 were analyzed. SP600125, a JNK inhibitor, was used to investigate the role of the JNK pathway in Wnt-5A induction of MMP-1, MMP-3, MMP-9, and MMP-13. Results Treatment of rabbit condylar chondrocytes with IL-1, up-regulated Wnt-5A expression. Purified Wnt-5A protein and transfection with Wnt-5A expression vector promoted the expression of MMP-1, MMP-3, MMP-9, and MMP-13. Wnt-5A did not cause accumulation and nuclear translocation of ,-catenin or activation of the ,-catenin-Tcf/Lef transcription complex. Instead, Wnt-5A activated JNK, and an inhibitor of JNK blocked the Wnt-5A,induced up-regulated expression of MMPs. Conclusion These findings indicate that IL-1, up-regulates Wnt-5A, and the activation of Wnt-5A signaling induces the expression of MMP-1, MMP-3, MMP-9, and MMP-13 via the JNK signaling pathway in rabbit TMJ condylar chondrocytes. Blockage of JNK signaling impairs the Wnt-5A,induced up-regulation of MMPs. Thus, Wnt-5A may be associated with cartilage destruction by promoting the expression of MMPs. [source]

HLA,B27,restricted antigen presentation by human chondrocytes to CD8+ T cells: Potential contribution to local immunopathologic processes in ankylosing spondylitis

Maren Kuhne
Objective Analysis of the histopathologic features of hip arthritis in patients with ankylosing spondylitis (AS) has revealed accumulation of infiltrating mononuclear cells in the bone end plate and presence of hyaline articular cartilage that is not found in areas of total cartilage destruction. This study was undertaken to assess whether chondrocytes attract lymphocytes and whether cartilage chondrocytes from patients with AS have the potential to directly stimulate T cells in an HLA-restricted manner. Methods Human HLA,B27+ T cell lines, specific for the Epstein-Barr virus,derived peptide EBNA258,266, and autologous chondrocytes, serving as nonprofessional antigen-presenting cells (APCs), were available for use in a model system to study chondrocyte functions in femoral head joint cartilage of patients with AS. Peptide functionality of cytotoxic T cells was assessed by flow cytometry, and cellular interactions were detected by fluorescence confocal microscopy. Results When maintained in an alginate matrix, chondrocytes isolated from the femoral heads of patients with AS constitutively expressed type II collagen and CD80. When pulsed with the EBNA258,266 peptide, autologous chondrocytes functioned as APCs and, specifically, induced interferon-, production in CD8+ T cells. In mixed chondrocyte,T cell cultures, cell,cell contacts were dependent on the presence of the EBNA258,266 peptide. T cells adjacent to chondrocytes produced perforin and granzyme B; both molecules were found in focal aggregates, a prerequisite for antigen-specific lysis of target cells. Conclusion Antigen presentation through human chondrocytes allows the stimulation of peptide-specific CD8+ T cells. These results indicate that human chondrocytes can act as nonprofessional APCs, and suggest that there is an interferon-,,triggered autocrine loop of immune cell,mediated chondrocyte activation in the already inflamed environment. Thus, local HLA-dependent activation of peptide-specific cytotoxic CD8+ T cells by chondrocytes might contribute to inflammatory processes in the spondylarthritides. [source]

Interleukin-7 stimulates secretion of S100A4 by activating the JAK/STAT signaling pathway in human articular chondrocytes

Raghunatha R. Yammani
Objective S100A4 has been shown to be increased in osteoarthritic (OA) cartilage and to stimulate chondrocytes to produce matrix metalloproteinase 13 (MMP-13) through activation of the receptor for advanced glycation end products (RAGE). The aim of this study was to examine the mechanism of S100A4 secretion by chondrocytes. Methods Human articular chondrocytes isolated from ankle cartilage were stimulated with 10 ng/ml of interleukin-1, (IL-1,), IL-6, IL-7, or IL-8. Cells were pretreated with either a JAK-3 inhibitor, brefeldin A, or cycloheximide. Immunoblotting with phospho-specific antibodies was used to determine the activation of signaling proteins. Secretion of S100A4 was measured in conditioned media by immunoblotting, and MMP-13 was measured by enzyme-linked immunosorbent assay. Results Chondrocyte secretion of S100A4 was observed after treatment with IL-6 or IL-8 but was much greater in cultures treated with equal amounts of IL-7 and was not observed after treatment with IL-1,. IL-7 activated the JAK/STAT pathway, with increased phosphorylation of JAK-3 and STAT-3, leading to increased production of S100A4 and MMP-13. Overexpression of a dominant-negative RAGE construct inhibited the IL-7,mediated production of MMP-13. Pretreatment of chondrocytes with a JAK-3 inhibitor or with cycloheximide blocked the IL-7,mediated secretion of S100A4, but pretreatment with brefeldin A did not. Conclusion IL-7 stimulates chondrocyte secretion of S100A4 via activation of JAK/STAT signaling, and then S100A4 acts in an autocrine manner to stimulate MMP-13 production via RAGE. Since both IL-7 and S100A4 are up-regulated in OA cartilage and can stimulate MMP-13 production by chondrocytes, this signaling pathway could contribute to cartilage destruction during the development of OA. [source]

Different amplifying mechanisms of interleukin-17 and interferon-, in Fc, receptor,mediated cartilage destruction in murine immune complex,mediated arthritis

Lilyanne C. Grevers
Objective Previously, we reported that interferon-, (IFN,) aggravates cartilage destruction in immune complex (IC),mediated arthritis via up-regulation of activating Fc, receptors (Fc,R). Recently, we found that interleukin-17 (IL-17) also aggravates cartilage destruction in arthritis models in which ICs are involved, but the underlying mechanism remains unknown. This study was undertaken to determine the role of IL-17 in Fc,R-mediated cartilage destruction in IC-mediated arthritis and to compare its effect with that of IFN,. Methods IC-mediated arthritis was passively induced in ,-chain,/, mice, which lack functional activating Fc,R, and in wild-type controls. AdIL-17 or a control vector was injected into the knee joints 1 day prior to induction of IC-mediated arthritis. Knee joints were isolated for histologic analysis, and synovium samples were obtained for reverse transcriptase,polymerase chain reaction (RT-PCR). Macrophage (RAW 264.7) cell lines and polymorphonuclear cell (PMN; 32Dcl3) lines were stimulated with IFN, or IL-17 for analysis of Fc,R expression using RT-PCR and fluorescence-activated cell sorting. Results IL-17 overexpression prior to induction of IC-mediated arthritis significantly aggravated cartilage destruction and inflammation, characterized by a massive influx of PMNs, which adhered to the cartilage surface. Although IL-17 overexpression increased Fc,R messenger RNA levels in the synovium, in vitro stimulation of macrophages and PMNs revealed that, in contrast to IFN,, IL-17 did not directly regulate Fc,R expression. Despite similar inflammation in AdIL-17,enhanced IC-mediated arthritis in ,-chain,/, mice and wild-type controls, severe cartilage destruction and PMN adherence were completely absent in ,-chain,/, mice. Conclusion Our findings indicate that IL-17,mediated aggravation of cartilage destruction in IC-mediated arthritis is Fc,R dependent. However, in contrast to IFN,, which directly up-regulates Fc,R expression on macrophages and PMNs, IL-17 enhances cartilage destruction by increasing the local amount of Fc,R-bearing neutrophils. [source]

Crucial role of macrophages in matrix metalloproteinase,mediated cartilage destruction during experimental osteoarthritis : Involvement of matrix metalloproteinase 3

Arjen B. Blom
Objective To explore the involvement of synovial macrophages in early cartilage damage in osteoarthritis (OA), and to identify the role of matrix metalloproteinase 3 (MMP-3) in the pathology of early and late OA. Methods The role of synovial macrophages in MMP-mediated damage in OA was studied by depleting synovial macrophages prior to elicitation of a collagenase-induced instability model of OA. The expression of MMP in synovium and cartilage was monitored using TaqMan analysis. In spontaneous and induced OA, cartilage pathology was scored in MMP-3,knockout mice and control mice, by histologic assessment and VDIPEN staining. Results On day 14 following induction of OA, MMP-mediated neoepitopes were detected in cartilage from mice with mild experimental OA (mean SD positively stained surface area 20 3.2%). Remarkably, by depleting synovial macrophages prior to induction of OA, the generation of MMP-induced neoepitopes was largely prevented (mean SD positively stained surface area 5 1%; P< 0.001), indicating an important role for synovial macrophages in the occurrence of MMP-mediated cartilage damage. We observed a strong decrease in MMP-3 and MMP-9 expression in synovial but not cartilage tissue in macrophage-depleted joints. Among 2-year-old mice, spontaneous OA,like changes in the lining layer were significantly decreased in MMP-3,knockout mice compared with control mice. Even more striking was the 67% reduction in the occurrence of severe cartilage damage in MMP-3,knockout mice. In addition, MMP-mediated VDIPEN expression was significantly decreased, indicating reduced MMP-mediated cartilage breakdown. Conclusion The results of this study prove that MMP-3 is involved in the generation of severe cartilage damage in murine OA. Synovial macrophages are crucial in early MMP activity and appear to mediate MMP production in synovium rather than cartilage. [source]

Molecular mechanisms of cartilage destruction: Mechanics, inflammatory mediators, and aging collide

Richard F. Loeser
First page of article [source]

Production of lipid peroxidation products in osteoarthritic tissues: New evidence linking 4-hydroxynonenal to cartilage degradation,

Barbara Morquette MSc
Objective The lipid peroxidation product 4-hydroxynonenal (HNE) is prominently produced in osteoarthritic (OA) synovial cells, but its specific contribution to cartilage destruction is not understood. This study was designed to test whether HNE signaling and binding are involved in OA cartilage degradation through type II collagen (CII) and matrix metalloproteinase 13 (MMP-13) modulation. Methods HNE levels in synovial fluid and in isolated OA chondrocytes treated with free radical donors were determined by enzyme-linked immunosorbent assay. The formation of the HNE/CII adducts was measured in cartilage explants by immunoprecipitation. Levels of CII and MMP-13 messenger RNA and protein were determined by reverse transcription,polymerase chain reaction, Western blotting, and by the use of commercial kits. Results Levels of HNE/protein adducts were higher in OA synovial fluid compared with normal synovial fluid and were higher in OA chondrocytes treated with free radical donors compared with untreated cells. In cartilage explants, HNE induced CII cleavage, as established by the generation of neoepitopes. The level of HNE/CII adducts was increased in OA cartilage explants incubated with free radical donors. Modification of CII by HNE accelerated its degradation by active MMP-13. In isolated OA chondrocytes, HNE inhibited the expression of CII and tissue inhibitor of metalloproteinases 1 and induced MMP-13 mainly through activation of p38 MAPK. In vitro, HNE binding to MMP-13 activated this enzyme at a molar ratio of 1:100 (MMP-13 to HNE). Conclusion The increased level of HNE in OA cartilage and the ability of HNE to induce transcriptional and posttranslational modifications of CII and MMP-13 suggest that this aldehyde could play a role in OA. [source]

A comparative genetic analysis between collagen-induced arthritis and pristane-induced arthritis

Peter Olofsson
Objective To compare the genetic regulation of collagen-induced arthritis (CIA) with that of pristane-induced arthritis (PIA) in rats. Methods A genome-wide linkage analysis of an (E3 DA)DA backcross of rats with CIA (n = 364 male rats; the same strain combinations as previously used to determine the genetic control of PIA) was performed. The strongest loci in both CIA and PIA (i.e., Cia12/Pia4 and Cia13/Pia7) were isolated in congenic strains. Susceptibility in both congenic strains was tested in rats with CIA and in rats with PIA. Results We found a striking, although not complete, similarity of the arthritis-controlling loci in CIA and in PIA, as well as the previously defined loci associated with cartilage destruction, antibody production, and the acute-phase response. All major PIA quantitative trait loci (QTLs) identified in early severe arthritis were also strong regulators of CIA. The 2 strongest QTLs, Cia12/Pia4 on chromosome 12 and Cia13/Pia7 on chromosome 4, were also analyzed in congenic strains with DA or E3 as the background genome. Consistent with the results of linkage analysis, the congenic strain experiments showed that the chromosome 4 locus was more penetrant in CIA than in PIA, while the chromosome 12 locus almost completely dominated the control of PIA severity. Conclusion The underlying genetic control of CIA was found to have many, but not all, pathogenic mechanisms in common with PIA, despite the use of a cartilage-specific antigen (type II collagen) to induce CIA but not PIA. [source]

Inhibition of insulin-like growth factor binding protein 5 proteolysis in articular cartilage and joint fluid results in enhanced concentrations of insulin-like growth factor 1 and is associated with improved osteoarthritis

David R. Clemmons
Objective The complement component C1s is present in dog joint fluid in an activated state. Since C1s degrades insulin-like growth factor binding protein 5 (IGFBP-5), we undertook to determine whether inhibiting C1s in joint fluid would result in an increase in the amount of intact IGFBP-5 and IGF-1 in cartilage and joint fluid, and whether C1s inhibition would be associated with a reduction in cartilage destruction during the development of osteoarthritis (OA). Methods Twenty-two dogs were randomized to 3 treatment groups. All dogs underwent anterior cruciate ligament transection and were exercised. Dogs received 1 of 3 treatments: buffer alone (controls; n = 6); PB-145, a peptide derived from the sequence of antithrombin III (n = 9); and pentosan polysulfate (PPS; n = 7). PB-145 or saline was injected into the joint space 3 times per week for 3 weeks. PPS was injected intramuscularly weekly for 3 weeks. Results Joint histology showed preservation of chondrocytes and a smooth joint surface in the animals treated with PB-145 and PPS. Mankin scoring showed statistically significant reductions in joint destruction with PB-145 and PPS treatments (P < 0.01) compared with buffer control. Mean active collagenase concentrations were decreased by these two treatments. Immunoblotting of joint fluid showed that both treatments increased concentrations of intact IGFBP-5. Direct analysis of IGFBP-3 and IGFBP-5 protease activity showed that IGFBP-5 was degraded more rapidly and that PB-145 and PPS inhibited the degradation of both proteins. Total IGF-1 concentrations in joint fluid were increased 5.6,5.8-fold by these two treatments. Analysis showed that C1s was being activated in joint fluid and that its activation was inhibited by the addition of PB-145 or PPS. Conclusion The findings suggest that direct inhibition of the serine protease C1s results in increased concentrations of intact IGFBP-5 and that proteolysis of IGFBP-3 is also inhibited, probably by the inhibition of some other protease. This increase in concentrations of intact IGFBP-3 and IGFBP-5 leads to an increase in IGF-1 which is associated with an improvement in joint architecture during the development of OA. [source]

The in,uence of ,1 -acid glycoprotein on collagenase-3 activity in early rheumatoid arthritis

J. Louise Haston
Abstract The concentration and glycosylation of ,1 -acid glycoprotein (AGP) alter signi,cantly during in,ammation. A de,nitive physiological role for AGP remains elusive and is the subject of extensive investigation. This study investigated the in,uence of AGP on the activity of collagenase-3, an important mediator of cartilage destruction in rheumatoid arthritis. AGP was isolated from normal and rheumatoid plasma. Fucosylation was determined by high pH anion-exchange chromatography; sialylation was assessed following enzymatic digest. Rheumatoid AGP displayed elevated fucosylation and sialylation compared with normal. The in,uence of each sample on collagenase-3 activity was measured ,uorometrically. AGP in,uenced collagenase-3 catalysis and collagen binding, with catalytic activity correlating with fucosylation. Rheumatoid AGP exhibited less ef,cient inhibition than normal plasma AGP. It is hypothesized that AGP within rheumatoid synovial ,uid may be inadequate to prevent excessive cartilage destruction and hence may exacerbate the disease process. Copyright 2003 John Wiley & Sons, Ltd. [source]

Benzo[d]isothiazol-3-yl-benzamidines: a Class of Protective Agents on Culture of Human Cartilage and Chondrocytes Stimulated by IL-1,

CHEMMEDCHEM, Issue 1 2007
Paola Vicini Prof.
Abstract New derivatives of N -benzo[d]isothiazol-3-yl-benzamidine 6,a were synthesized as nonacidic anti-inflammatory/antidegenerative agents. We investigated the influence of the amidines 6,a,j on the production of NO, PGE2, MMP-3, COX-2, ROS, and GAGs, key molecules involved in cartilage destruction in osteoarthritic diseases. The antidegenerative properties of the novel designed derivatives 6,b,j were improved with respect to N -benzo[d]isothiazol-3-yl-benzamidine 6,a. All of the compounds 6,a,j promoted the reduction of most of the IL-1,-induced harmful effects. Derivatives 6,d, 6,h, and 6,j were the most potent of all the tested compounds, particularly in the human chondrocyte culture model. [source]