Complement deficiency ameliorates collagen-induced arthritis in mice

Collagen-induced arthritis (CIA) is an experimental animal model of human rheumatoid arthritis being characterized by synovitis and progressive destruction of cartilage and bone. CIA is induced by injection of heterologous or homologous collagen type II in a susceptible murine strain. DBA/1J mice deficient of complement factors C3 (C3(-/-)) and factor B (FB(-/-)) were generated to elucidate the role of the complement system in CIA. When immunized with bovine collagen type II emulsified in CFA, control mice developed severe arthritis and high CII-specific IgG Ab titers. In contrast, the C3(-/-) and FB(-/-) were highly resistant to CIA and displayed decreased CII-specific IgG Ab response. A repeated bovine collagen type II exposure 3 wk after the initial immunization led to an increase in the Ab response in all mice and triggered arthritis also in the complement-deficient mice. Although the arthritic score of the C3(-/-) mice was low, the arthritis in FB(-/-) mice ranked intermediate with regard to C3(-/-) and control mice. We conclude that complement activation by both the classical and the alternative pathway plays a deleterious role in CIA.     

Hepatocyte growth factor significantly suppresses collagen-induced arthritis in mice

Hepatocyte growth factor (HGF) plays an important role in angiogenesis, cell proliferation, antifibrosis, and antiapoptosis. Moreover, recent studies have highlighted the immunosuppressive effect of HGF in animal models of allogenic heart transplantation and autoimmune myocarditis and in studies in vitro as well. We also reported that HGF significantly suppresses dendritic cell function, thus down-regulating Ag-induced Th1-type and Th2-type immune responses in allergic airway inflammation. However, the immunosuppressive effect of HGF in many other situations has not been fully clarified. In the present study, using a mouse model of collagen-induced arthritis (CIA) and experiments in vitro, we examined the effect of HGF on autoimmune arthritis and then elucidated the mechanisms of action of HGF. To achieve sufficient delivery of HGF, we used biodegradable gelatin hydrogels as a carrier. HGF suppressed Ag-induced T cell priming by regulating the functions of dendritic cells in the Ag-sensitization phase with down-regulation of IL-10. In contrast, under continuous Ag stimulation HGF induced IL-10-producing immunocytes both in vivo and in vitro. Moreover, HGF potently inhibited the development of CIA with enhancing the Th2-type immune response. We also confirmed that HGF significantly suppressed the production of IL-17 by immunocytes. These results indicate that HGF suppresses the development of CIA through different ways at different phases. They also suggest that HGF could be an attractive tool for treating patients with rheumatoid arthritis.     

Resistance to collagen-induced arthritis in SHPS-1 mutant mice

SHPS-1 is a transmembrane protein that binds the protein tyrosine phosphatases SHP-1 and SHP-2 through its cytoplasmic region and is abundantly expressed on dendritic cells and macrophages. Here we show that mice expressing a mutant form of SHPS-1 fail to develop type-II collagen (CII)-induced arthritis (CIA), a model for rheumatoid arthritis in humans. Histological examinations of the arthritic paws from immunized wild-type mice revealed that cartilage was destroyed in association with marked mononuclear cell infiltration, while only mild cell infiltration was observed in immunized SHPS-1 mutant mice. Consistently, the serum levels of both IgG and IgG2a specific to CII and of IL-1β in immunized SHPS-1 mutant mice were markedly reduced compared with those apparent for wild-type mice. The CII-induced proliferation of, and production of cytokines by, T cells from immunized SHPS-1 mutant mice were reduced compared to wild-type cells. These results suggest that SHPS-1 is essential for development of CIA.     

Bacterial lipopolysaccharide potentiates type II collagen-induced arthritis in mice

Collagen-induced arthritis (CIA) is an immunologically relevant animal model of human rheumatoid arthritis. Studies comparing the disease incidence in genetically susceptible male and female DBA/1LacJ mice demonstrated that under low density/low stress housing conditions, female mice had earlier onset (day 35) and higher disease incidence (25%) than the male mice (17% at day 49) when immunized with bovine type II collagen. A single subcutaneous or intraperitoneal injection of bacterial lipopolysaccharide (LPS) 17-24 days after collagen immunization greatly potentiated this standard CIA model in a dose related manner. 20-40 mug of LPS accelerated the onset of disease from day 35 to day 21 and exacerbated the clinical severity score from 0.27 to 2.00 at day 42. A similar administration of 6 mug of recombinant interleukin-beta produced a comparable potentiated CIA model. The acute phase protein, serum amyloid P (SAP), was elevated in the serum at day 26 to 440 mug ml(-1) for the LPS potentiated CIA mice compared to 65 mug ml(-1) in the non-potentiated immunized CIA mice. There was a significant correlation (r = 0.78) between SAP levels and disease expression in the LPS treated CIA mice. The rapidity and uniformity of disease expression in this LPS potentiated CIA model will allow more and different drugs to be evaluated with a smaller number of animals.     

Identification of collagen-induced arthritis loci in aged multiparous female mice

Collagen-induced arthritis in mice is one of the most commonly used autoimmune experimental models, with many similarities to rheumatoid arthritis. Since collagen-induced arthritis is a complex polygenic disease there is a need for identification of several major disease-controlling genes. Because rheumatoid arthritis particularly affects aged women, we have in the present study identified new genetic regions critical for collagen-induced arthritis by studying aged female mice of a cross between NFR/N and B10.Q (H-2^q haplotype). The mice in the present study had different reproductive histories, which did not significantly affect the onset, incidence or severity of the disease. A total of 200 female mice were used in a total genome-wide screening with 125 microsatellite markers. We found one new significant quantitative trait locus affecting the arthritis incidence, severity and day of onset on chromosome 11 (denoted Cia40), which colocalizes with a locus controlling pregnancy failure. Furthermore, a quantitative trait locus of suggestive significance associated with the incidence, severity and day of onset was identified on chromosome 1. Finally, a suggestively significant quantitative trait locus associated with collagen type II antibody titers was identified on chromosome 13. This study indicates that several gene loci control arthritis in aged multiparous females, and that at least one of these loci coincides with pregnancy failure.     

Oral administration of lipopolysaccharide exacerbates collagen-induced arthritis in mice.

We investigated whether oral administration of LPS exacerbated collagen-induced arthritis (CIA) in mice, which was an experimental model of autoimmune disease. CIA was induced by s.c. injection of type II collagen emulsified with CFA into the base of the tail (day 0) followed by a booster injection on day 21. To examine the ability of LPS to exacerbate CIA, varying doses of LPS were orally administered on day 50. The results showed that administration of LPS was followed by reactivation of CIA in a dose-related fashion. Histologically, on day 55 there were marked edema of synovium proliferated by day 50, new formation of fibrin, and intense infiltration of neutrophils accompanied with a large number of mononuclear cells. Severe destruction of cartilage and subchondral bone was also observed on day 70. The reactivation of CIA by oral administration of LPS was associated with increase in anti-type II collagen IgG and IgG2a Abs as well as varying kinds of cytokines including IL-12, IFN-gamma, IL-1beta, and TNF-alpha. Polymyxin B sulfate given either orally or i.v. suppressed the recurrence of CIA. Increased amounts of LPS were found in sera of mice given the endotoxin orally. LPS from Salmonella enteritidis, Salmonella typhimurium, and Klebsiella pneumoniae and its component, lipid A from Escherichia coli, also reactivated the disease. These findings suggest that LPS from intestinal bacteria may play a role in the exacerbation of autoimmune joint inflammation.     

CD97 neutralisation increases resistance to collagen-induced arthritis in mice

Synovial tissue of rheumatoid arthritis (RA) patients is characterised by an influx and retention of CD97-positive inflammatory cells. The ligands of CD97, CD55, chondroitin sulfate B, and α5β1 (very late antigen [VLA]-5) are expressed abundantly in the synovial tissue predominantly on fibroblast-like synoviocytes, endothelium, and extracellular matrix. Based upon this expression pattern, we hypothesise CD97 expression to result in accumulation of inflammatory cells in the synovial tissue of RA patients. To determine the therapeutic effect of blocking CD97 in an animal model of RA, collagen-induced arthritis was induced in a total of 124 DBA/J1 mice. Treatment was started on day 21 (early disease) or on day 35 (longstanding disease) with the blocking hamster anti-mouse CD97 monoclonal antibody (mAb) 1B2, control hamster immunoglobulin, or NaCl, applied intraperitoneally three times a week. The paws were evaluated for clinical signs of arthritis and, in addition, examined by radiological and histological analysis. Mice receiving 0.5 mg CD97 mAb starting from day 21 had significantly less arthritis activity and hind paw swelling. Furthermore, joint damage and inflammation were reduced and granulocyte infiltration was decreased. When treatment was started on day 35, CD97 mAb treatment had similar effects, albeit less pronounced. The results support the notion that CD97 contributes to synovial inflammation and joint destruction in arthritis.     

A CD4 cell is capable of transferring suppression of collagen-induced arthritis

Collagen-induced arthritis can be suppressed by i.v. injection of intact type II collagen (CII) but not type I collagen before immunization. To identify the mechanism mediating this suppression, splenocytes were obtained from mice injected with CII or OVA and administered to recipients that were subsequently immunized with CII. Mice receiving cells from donors injected with CII had a lower incidence of arthritis and lower antibody titers than those receiving cells from OVA-injected donors. Treatment of cells with 3000 rad of gamma-irradiation abrogated the suppression. To determine the phenotype of these donor cells, spleen cells were fractionated by adherence to plates coated with mouse anti-IgG to enrich for Thy-1+ phenotype. Thy-1+ cells injected into naive mice could significantly suppress arthritis. Further depletion of T cell subsets by panning revealed that depletion of CD4+ cells prevented the transfer of suppression whereas removal of CD8+ cells had no effect. Isolated CD4+ cells transferred into naive mice were also suppressive. Recently the Pgp-1 (Ly-24) Ag has been described to identify a unique memory subset of CD4+ cells when present on the cell surface. In CII-tolerized spleen populations, removal of the Pgp-1+ (Ly-24) subset of T cells abrogated suppression and transfer of isolated Pgp-1+ cells suppressed arthritis. These findings indicate that the Pgp-1+ subset of CD4+ cells can suppress collagen-induced arthritis and suggest that a CD4+ memory cell down-regulates autoimmunity. In addition, treatment of donor animals with cyclosporin, which inhibits the development of CD4+ cells, abrogated suppression.     

Smoking and nicotine exposure delay development of collagen-induced arthritis in mice

Introduction  

Recent epidemiologic studies have implicated smoking as an environmental risk factor for the development of rheumatoid arthritis (RA). The aim of the present study is the evaluation of the role of cigarette smoke (CS) in the pathogenesis of collagen-induced arthritis in mice.     

Suppression of immune induction of collagen-induced arthritis in IL-17-deficient mice

Interleukin-17 is a T cell-derived proinflammatory cytokine. This cytokine is suspected to be involved in the development of rheumatoid arthritis (RA) because this cytokine expression is augmented in synovial tissues of RA patients. The pathogenic roles of IL-17 in the development of RA, however, still remain to be elucidated. In this study, effects of IL-17 deficiency on collagen-induced arthritis (CIA) model were examined using IL-17-deficient mice (IL-17(-/-) mice). We found that CIA was markedly suppressed in IL-17(-/-) mice. IL-17 was responsible for the priming of collagen-specific T cells and collagen-specific IgG2a production. Thus, these observations suggest that IL-17 plays a crucial role in the development of CIA by activating autoantigen-specific cellular and humoral immune responses.     

Abrogation of CC chemokine receptor 9 ameliorates collagen-induced arthritis of mice

Introduction

Biological drugs are effective in patients with rheumatoid arthritis (RA), but increase severe infections. The CC chemokine receptor (CCR) 9 antagonist was effective for Crohn’s disease without critical adverse effects including infections in clinical trials. The present study was carried out to explore the pathogenic roles of chemokine (C-C motif) ligand (CCL) 25 and its receptor, CCR9, in autoimmune arthritis and to study if the CCR9 antagonist could be a new treatment for RA.

Methods

CCL25 and CCR9 expression was examined with immunohistochemistry and Western blotting. Concentration of interleukin (IL)-6, matrix metalloproteinase (MMP)-3 and tumor necrosis factor (TNF)-α was measured with enzyme-linked immunosorbent assays. Effects of abrogating CCR9 on collagen-induced arthritis (CIA) was evaluated using CCR9-deficient mice or the CCR9 antagonist, CCX8037. Fluorescence labeled-CD11b⁺ splenocytes from CIA mice were transferred to recipient CIA mice and those infiltrating into the synovial tissues of the recipient mice were counted.

Results

CCL25 and CCR9 proteins were found in the RA synovial tissues. CCR9 was expressed on macrophages, fibroblast-like synoviocytes (FLS) and dendritic cells in the synovial tissues. Stimulation with CCL25 increased IL-6 and MMP-3 production from RA FLS, and IL-6 and TNF-α production from peripheral blood monocytes. CIA was suppressed in CCR9-deficient mice. CCX8037 also inhibited CIA and the migration of transferred CD11b⁺ splenocytes into the synovial tissues.

Conclusions

The interaction between CCL25 and CCR9 may play important roles in cell infiltration into the RA synovial tissues and inflammatory mediator production. Blocking CCL25 or CCR9 may represent a novel safe therapy for RA.     

Acceleration and increased severity of collagen-induced arthritis in P-selectin mutant mice.

P-selectin plays an important role in leukocyte adherence to microvascular endothelium and is expressed in synovial tissue from patients with rheumatoid arthritis (RA). However, the contribution of P-selectin to the initiation and chronicity of joint inflammation is not well understood. In these studies, collagen-induced arthritis (CIA) was induced in P-selectin mutant (-/-) mice to explore the role of P-selectin in the development of joint inflammation. Surprisingly, CIA onset was accelerated and severity was increased in P-selectin mutant mice, compared with wild-type mice (+/+). Increased levels of anti-type II collagen IgG were detected in both nonarthritic and arthritic P-selectin mutant mice from days 14-91. In addition, splenocytes isolated from immunized and nonimmunized P-selectin mutant mice produced significantly less IL-2 and IL-4, but significantly higher levels of IL-10 and IL-5 than splenocytes from wild-type mice. These observations show that P-selectin-mediated leukocyte rolling is not required for the development of murine CIA and that P-selectin expression exerts a controlling effect on the development of Ag-driven inflammatory joint disease, possibly by mediating the recruitment and/or trafficking of specific leukocyte subtypes into lymphoid tissue or inflammatory foci.     

Inhibition of indoleamine 2,3-dioxygenase-mediated tryptophan catabolism accelerates collagen-induced arthritis in mice

Indoleamine 2,3-dioxygenase (IDO) is one of the initial and rate-limiting enzymes involved in the catabolism of the essential amino acid tryptophan. In cultured cells, the induction of IDO leads to depletion of tryptophan and tryptophan starvation. Recent studies suggest that modulation of tryptophan concentration via IDO plays a fundamental role in innate immune responses. Induction of IDO by interferon-γ in macrophages and dendritic cells results in tryptophan depletion and suppresses the immune-mediated activation of fibroblasts and T, B, and natural killer cells. To assess the role of IDO in collagen-induced arthritis (CIA), a model of rheumatoid arthritis characterized by a primarily Th1-like immune response, activity of IDO was inhibited by 1-methyl-tryptophan (1-MT) in vivo. The results showed significantly increased incidence and severity of CIA in mice treated with 1-MT. Activity of IDO, as determined by measuring the levels of kynurenine/tryptophan ratio in the sera, was increased in the acute phase of arthritis and was higher in collagen-immunized mice that did not develop arthritis. Treatment with 1-MT resulted in an enhanced cellular and humoral immune response and a more dominant polarization to Th1 in mice with arthritis compared with vehicle-treated arthritic mice. The results demonstrated that development of CIA was associated with increased IDO activity and enhanced tryptophan catabolism in mice. Blocking IDO with 1-MT aggravated the severity of arthritis and enhanced the immune responses. These findings suggest that IDO may play an important and novel role in the negative feedback of CIA and possibly in the pathogenesis of rheumatoid arthritis.     

Immunosuppression of collagen-induced arthritis in mice with an anti-IL-2 receptor antibody

The use of an anti-IL-2R antibody, 7D4, was investigated in vivo in the suppression of collagen-induced arthritis in mice. 7D4 was shown to reduce the incidence of arthritis in a group of mice immunized with type II collagen as compared with a group similarly immunized with collagen and treated with a control isotype matched anti-Forsmann antibody. 7D4 was also shown to reduce the severity of arthritis in the treated mice as compared to the mice in the group treated with the control antibody. Anti-IL-2R antibodies may be useful in the treatment of autoimmune diseases by selectively suppressing activated T cells.     

A proinflammatory role for Fas in joints of mice with collagen-induced arthritis

Collagen-induced arthritis (CIA) is a chronic inflammatory disease bearing all the hallmarks of rheumatoid arthritis, e.g. polyarthritis, synovitis, and subsequent cartilage/bone erosions. One feature of the disease contributing to joint damage is synovial hyperplasia. The factors responsible for the hyperplasia are unknown; however, an imbalance between rates of cell proliferation and cell death (apoptosis) has been suggested. To evaluate the role of a major pathway of cell death – Fas (CD95)/FasL – in the pathogenesis of CIA, DBA/1J mice with a mutation of the Fas gene (lpr) were generated. The susceptibility of the mutant DBA-lpr/lpr mice to arthritis induced by collagen type II was evaluated. Contrary to expectations, the DBA-lpr/lpr mice developed significantly milder disease than the control littermates. The incidence of disease was also significantly lower in the lpr/lpr mice than in the controls (40% versus 81%; P < 0.05). However DBA-lpr/lpr mice mounted a robust immune response to collagen, and the expression of local proinflammatory cytokines such as, e.g., tumor necrosis factor α (TNF-α) and IL-6 were increased at the onset of disease. Since the contribution of synovial fibroblasts to inflammation and joint destruction is crucial, the potential activating effect of Fas on mouse fibroblast cell line NIH3T3 was investigated. On treatment with anti-Fas in vitro, the cell death of NIH3T3 fibroblasts was reduced and the expression of proinflammatory cytokines TNF-α and IL-6 was increased. These findings suggest that impairment of immune tolerance by increased T-cell reactivity does not lead to enhanced susceptibility to CIA and point to a role of Fas in joint destruction.     

Effects of selective iNOS inhibition on type II collagen-induced arthritis in mice

Nitric oxide as well as prostaglandins has been reported to play an important role in inflammatory diseases including arthritis. In the present study, the effects of iNOS inhibition on development of disease were examined in type II collagen-induced arthritis (CIA) in male DBA/1J mice. From 4 weeks after the first immunization with bovine type II collagen, 1400W (10 mg/kg/day, p.o.), a selective iNOS inhibitor, indomethacin (1 mg/kg/day, p.o.), a cyclooxygenase (COX) inhibitor, or 1400W + indomethacin was administered for 8 weeks. Immunization with type II collagen evoked arthritic inflammation of paws and bone destruction accompanied by increases in urinary nitrite/nitrate (NOx) excretion, plasma NOx and PGE2 levels. Administration of 1400W reduced urinary NOx excretion and increased plasma PGE2 levels, while it had no effect on arthritic inflammation or bone destruction. Indomethacin slightly reduced the inflammatory signs and bone destruction with marked reduction of plasma PGE2. Combination of 1400W and indomethacin reduced urinary NOx and PGE2 levels, and showed greater amelioration of inflammatory signs and bone destruction than either alone. In conclusion, 1400W, a selective iNOS inhibitor, failed to prevent CIA probably due to its increasing effect on PGE2 production, but showed a synergistic ameliorative effect in combination with indomethacin.     

Adenoviral transfer of cyclin-dependent kinase inhibitor genes suppresses collagen-induced arthritis in mice

In rheumatoid synovial tissues, synovial fibroblasts are activated by proinflammatory cytokines and proliferate to develop hyperplastic pannus tissues, which irreversibly damage the affected joints. We recently reported that the cyclin-dependent kinase inhibitors p16(INK4a) and p21(Cip1) are not expressed in vivo in rheumatoid synovial fibroblasts, but are readily inducible in vitro. This observation was followed by the successful treatment of rat adjuvant arthritis by local p16(INK4a) gene transfer, showing that the inhibition of the cell cycle of the synovial cells ameliorates the arthritis. In this study, we show that another animal model of rheumatoid arthritis, murine collagen-induced arthritis, can be effectively treated by local gene transfer of p21(Cip1) as well as that of p16(INK4a). The anti-arthritic effects were observed even when the treatment was conducted after the arthritis had developed. Furthermore, the effects included suppression of the expression of proinflammatory cytokines such as IL-1ss, IL-6, and TNF-alpha. Our results demonstrate that the ectopic expression of cyclin-dependent kinase inhibitors not only prevents synovial overgrowth but also ameliorates the proinflammatory milieu in the affected joints. The induction of p21(Cip1) in rheumatoid synovial tissues by pharmacological agents may also be an effective strategy to treat rheumatoid arthritis.     

LFA-1基因敲出鼠胶原诱导风湿性关节炎发病率及程度的降低

淋巴细胞功能相关抗原（LFA-1）属于黏附分子家族,在细胞相互作用中发挥重要作用。通过观察LFA-1基因敲除小鼠的胶原诱导关节炎(CIA)发病率、放射线学及组织学变化,探讨LFA-1分子在CIA发病中的作用。实验采用100μg的二型胶原(CII)加弗氏完全佐剂充分混合,在LFA-1基因敲除小鼠及正常对照组小鼠尾根部皮内注射,21天后重复免疫一次,随后进行发病率、放射线学及组织学分析。研究结果显示,CII免疫后,正常对照组小鼠平均发病率为57%,临床可见明显的放射线及组织学的异常变化。而LFA-1基因敲除小鼠无发病,放射线及组织学检查亦无明显异常改变。上述结果提示LFA-1在胶原诱导的关节炎发病中起重要作用。