Circulating C3 is necessary and sufficient for induction of autoantibody-mediated arthritis in a mouse model

Overview on the Link Between the Complement System and Auto-Immune Articular and Pulmonary Disease

Complement system (CS) dysregulation is a key factor in the pathogenesis of different autoimmune diseases playing a central role in many immune innate and adaptive processes. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by ta breach of self-tolerance leading to a synovitis and extra-articular manifestations. The CS is activated in RA and seems not only to mediate direct tissue damage but also play a role in the initiation of RA pathogenetic mechanisms through interactions with citrullinated proteins. Interstitial lung disease (ILD) represents the most common extra-articular manifestation that can lead to progressive fibrosis. In this review, we focused on the evidence of CS dysregulation in RA and in ILD, and highlighted the role of the CS in both the innate and adaptive immune responses in the development of diseases, by using idiopathic pulmonary fibrosis as a model of lung disease. As a proof of concept, we dissected the evidence that several treatments used to treat RA and ILD such as glucocorticoids, pirfenidone, disease modifying antirheumatic drugs, targeted biologics such as tumor necrosis factor (TNF)-inhibitors, rituximab, tocilizumab, and nintedanib may act indirectly on the CS, suggesting that the CS might represent a potential therapeutic target in these complex diseases.

Complement as a Therapeutic Target in Systemic Autoimmune Diseases

The complement system (CS) includes more than 50 proteins and its main function is to recognize and protect against foreign or damaged molecular components. Other homeostatic functions of CS are the elimination of apoptotic debris, neurological development, and the control of adaptive immune responses. Pathological activation plays prominent roles in the pathogenesis of most autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, dermatomyositis, and ANCA-associated vasculitis. In this review, we will review the main rheumatologic autoimmune processes in which complement plays a pathogenic role and its potential relevance as a therapeutic target.

Plasmacytoid dendritic cells in the eye

Plasmacytoid dendritic cells (pDCs) are a unique subpopulation of immune cells, distinct from classical dendritic cells. pDCs are generated in the bone marrow and following development, they typically home to secondary lymphoid tissues. While peripheral tissues are generally devoid of pDCs during steady state, few tissues, including the lung, kidney, vagina, and in particular ocular tissues harbor resident pDCs. pDCs were originally appreciated for their potential to produce large quantities of type I interferons in viral immunity. Subsequent studies have now unraveled their pivotal role in mediating immune responses, in particular in the induction of tolerance. In this review, we summarize our current knowledge on pDCs in ocular tissues in both mice and humans, in particular in the cornea, limbus, conjunctiva, choroid, retina, and lacrimal gland. Further, we will review our current understanding on the significance of pDCs in ameliorating inflammatory responses during herpes simplex virus keratitis, sterile inflammation, and corneal transplantation. Moreover, we describe their novel and pivotal neuroprotective role, their key function in preserving corneal angiogenic privilege, as well as their potential application as a cell-based therapy for ocular diseases.

Association Between Genetic Polymorphisms of CR2 Gene and the Risk of Steroid-Induced Osteonecrosis of the Femoral Head in the Chinese Han Male Population

Background: Multiple lines of evidence have suggested that genetic factors may contribute to steroid-induced osteonecrosis of the femoral head (SONFH). Complement receptor 2 (CR2), constituting a family of regulators of complement activation, has been recently reported to be associated with osteonecrosis of the femoral head (ONFH) in Koreans. The aim of this study was to evaluate the relationships between polymorphisms of the CR2 gene and susceptibility to SONFH in the male Han Chinese population. Materials and Methods: A total of 468 SONFH patients and 1224 healthy controls were recruited for this study. Ten tag single nucleotide polymorphisms (SNPs) located within the CR2 gene were genotyped. Genetic association analyses, including SNP and haplotypic analyses, were performed for the 10 SNPs. Furthermore, bioinformatic analyses were conducted to examine the functional consequences of SNPs shown to be significantly associated with SONFH. Results: An intronic SNP, rs311306, was identified to be significantly associated with the risk of SONFH (p = 0.0008, odds ratio = 1.44). Allelic analyses showed that the C allele of this SNP significantly elevated the risk of SONFH, which was replicated in genotypic association analyses. Moreover, a 3-SNP haplotype was significantly associated with SONFH (rs311306-rs17044576-rs3767933, p = 7.49 × 10^-8). Furthermore, bioinformatic analyses indicated limited functional consequences of SNP rs311306, but a complex interaction network was constructed for the protein encoded by the SLC44A2 gene and proteins encoded by the CD19, CD81, and C3 genes. Conclusion: Our findings shed new light on the link between the CR2 gene and SONFH in Han Chinese males, providing clues as to the nature of the mechanisms involved in the etiology of ONFH.

A time-course microarray data analysis reveals consistent dysregulated genes and upstream microRNAs in autoantibody-mediated arthritis

Background

The purpose of this study is to identify key genes and microRNAs (miRNAs) involved in autoantibody-mediated arthritis (AMA).

Methods

A time-course microarray data (ID: GSE27492) of peripheral blood leukocytes, ankle tissue, and synovial fluid from K/BxN mouse serum-transferred mice were downloaded from Gene Expression Omnibus. Those samples were collected at days 0, 1, 3, 7, 12, and 18 after serum injection. Limma of R was employed to identify differentially expressed genes (DEGs) in samples collected at days 1–18 compared with those collected at day 0. Consistent DEGs were obtained by taking the interaction of DEGs from different time points, followed by functional enrichment analysis. MiRNAs were screened out and constructed into regulatory network with DEGs using Cytoscape.

Results

In total, 17 consistent DEGs were obtained, including downregulated Ephx1 and upregulated AF251705, Adam8, Arg1, Basp1, Ccl2, Ccl7, Ccl9, Ccr2, Clec4a2, Clec4d, Cxcl1, Fabp5, Fcgr1, Gp49a, Il1rn, and Saa3. Those DEGs were associated with biological processes of immune response, inflammatory response, and defense response; chemokine signaling pathway; cytokine-cytokine receptor interaction; and NOD-like receptor signaling pathway. Additionally, 202 miRNAs were identified to have a regulatory effect on 9 of the 17 DEGs. Notably, miR-944, miR-374a, and miR374b were found to regulate the expression of Cxcl1, Ccl7, and Ccl2. Clec4d was targeted by 78 miRNAs.

Conclusions

Our study reveals that 17 DEGs and 202 miRNAs may be associated with autoimmune disorder in the progression of AMA, which could guide future researches.

Therapeutic Modulation of Plasmacytoid Dendritic Cells in Experimental Arthritis

OBJECTIVE

The role of plasmacytoid dendritic cells (PDCs) and type I interferons (IFNs) in rheumatoid arthritis (RA) remains a subject of controversy. This study was undertaken to explore the contribution of PDCs and type I IFNs to RA pathogenesis using various animal models of PDC depletion and to monitor the effect of localized PDC recruitment and activation on joint inflammation and bone damage.

METHODS

Mice with K/BxN serum-induced arthritis, collagen-induced arthritis, and human tumor necrosis factor transgene insertion were studied. Symptoms were evaluated by visual scoring, quantification of paw swelling, determination of cytokine levels by enzyme-linked immunosorbent assay, and histologic analysis. Imiquimod-dependent therapeutic effects were monitored by transcriptome analysis (using quantitative reverse transcriptase-polymerase chain reaction) and flow cytometric analysis of the periarticular tissue.

RESULTS

PDC-deficient mice showed exacerbation of inflammatory and arthritis symptoms after arthritogenic serum transfer. In contrast, enhancing PDC recruitment and activation to arthritic joints by topical application of the Toll-like receptor 7 (TLR-7) agonist imiquimod significantly ameliorated arthritis in various mouse models. Imiquimod induced an IFN signature and led to reduced infiltration of inflammatory cells.

CONCLUSION

The therapeutic effects of imiquimod on joint inflammation and bone destruction are dependent on TLR-7 sensing by PDCs and type I IFN signaling. Our findings indicate that local recruitment and activation of PDCs represents an attractive therapeutic opportunity for RA patients.

K/BxN Serum-Transfer Arthritis as a Model for Human Inflammatory Arthritis

The K/BxN serum-transfer arthritis (STA) model is a murine model in which the immunological mechanisms occurring in rheumatoid arthritis (RA) and other arthritides can be studied. To induce K/BxN STA, serum from arthritic transgenic K/BxN mice is transferred to naive mice and manifestations of arthritis occur a few days later. The inflammatory response in the model is driven by autoantibodies against the ubiquitously expressed self-antigen, glucose-6-phosphate isomerase (G6PI), leading to the formation of immune complexes that drive the activation of different innate immune cells such as neutrophils, macrophages, and possibly mast cells. The pathogenesis further involves a range of immune mediators including cytokines, chemokines, complement factors, Toll-like receptors, Fc receptors, and integrins, as well as factors involved in pain and bone erosion. Hence, even though the K/BxN STA model mimics only the effector phase of RA, it still involves a wide range of relevant disease mediators. Additionally, as a murine model for arthritis, the K/BxN STA model has some obvious advantages. First, it has a rapid and robust onset of arthritis with 100% incidence in genetically identical animals. Second, it can be induced in a wide range of strain backgrounds and can therefore also be induced in gene-deficient strains to study the specific importance of disease mediators. Even though G6PI might not be an essential autoantigen, for example, in RA, the K/BxN STA model is a useful tool to understand how autoantibodies, in general, drive the progression of arthritis by interacting with downstream components of the innate immune system. Finally, the model has also proven useful as a model wherein arthritic pain can be studied. Taken together, these features make the K/BxN STA model a relevant one for RA, and it is a potentially valuable tool, especially for the preclinical screening of new therapeutic targets for RA and perhaps other forms of inflammatory arthritis. Here, we describe the molecular and cellular pathways in the development of K/BxN STA focusing on the recent advances in the understanding of the important mechanisms. Additionally, this review provides a comparison of the K/BxN STA model to some other arthritis models.

CD55 deposited on synovial collagen fibers protects from immune complex-mediated arthritis

INTRODUCTION

CD55, a glycosylphosphatidylinositol-anchored, complement-regulating protein (decay-accelerating factor), is expressed by fibroblast-like synoviocytes (FLS) with high local abundance in the intimal lining layer. We here explored the basis and consequences of this uncommon presence.

METHODS

Synovial tissue, primary FLS cultures, and three-dimensional FLS micromasses were analyzed. CD55 expression was assessed by quantitative polymerase chain reaction (PCR), in situ hybridization, flow cytometry, and immunohistochemistry. Reticular fibers were visualized by Gomori staining and colocalization of CD55 with extracellular matrix (ECM) proteins by confocal microscopy. Membrane-bound CD55 was released from synovial tissue with phospholipase C. Functional consequences of CD55 expression were studied in the K/BxN serum transfer model of arthritis using mice that in addition to CD55 also lack FcγRIIB (CD32), increasing susceptibility for immune complex-mediated pathology.

RESULTS

Abundant CD55 expression seen in FLS of the intimal lining layer was associated with linearly oriented reticular fibers and was resistant to phospholipase C treatment. Expression of CD55 colocalized with collagen type I and III as well as with complement C3. A comparable distribution of CD55 was established in three-dimensional micromasses after ≥3 weeks of culture together with the ECM. CD55 deficiency did not enhance K/BxN serum-induced arthritis, but further exaggerated disease activity in Fcgr2b (-/-) mice.

CONCLUSIONS

CD55 is produced by FLS and deposited on the local collagen fiber meshwork, where it protects the synovial tissue against immune complex-mediated arthritis.

Roles of adipocytes and fibroblasts in activation of the alternative pathway of complement in inflammatory arthritis in mice

The complement system is involved in mediation of joint damage in rheumatoid arthritis, with evidence suggesting activation of both the classical and alternative pathway (AP). The AP is both necessary and sufficient to mediate collagen Ab-induced arthritis, an experimental animal model of immune complex-induced joint disease. The AP in mice is dependent on MASP-1/3 cleavage of pro-factor D (pro-FD) into mature factor D (FD). The objectives of the current study were to determine the cells synthesizing MASP-1/3 and pro-FD in synovial tissue. Collagen Ab-induced arthritis was studied in wild-type C57BL/6 mice, and the localization of mRNA and protein for FD and MASP-1/3 in synovial adipose tissue (SAT) and fibroblast-like synoviocytes (FLS) was determined using various techniques, including laser capture microdissection. SAT was the sole source of mRNA for pro-FD. Cultured differentiated 3T3 adipocytes, a surrogate for SAT, produced pro-FD but no mature FD. FLS were the main source of MASP-1/3 mRNA and protein. Using cartilage microparticles (CMPs) coated with anti-collagen mAb and serum from MASP-1/3(-/-) mice as a source of factor B, pro-FD in 3T3 supernatants was cleaved into mature FD by MASP-1/3 in FLS supernatants. The mature FD was eluted from the CMP, and was not present in the supernatants from the incubation with CMP, indicating that cleavage of pro-FD into mature FD by MASP-1 occurred on the CMP. These results demonstrate that pathogenic activation of the AP can occur in the joint through immune complexes adherent to cartilage and the local production of necessary AP proteins by adipocytes and FLS.

Essential role of surface-bound complement factor H in controlling immune complex-induced arthritis

Factor H (fH) is an endogenous negative regulator of the alternative pathway (AP) that binds polyanions as well as complement activation fragments C3b and C3d. The AP is both necessary and sufficient to develop collagen Ab-induced arthritis (CAIA) in mice; the mechanisms whereby normal control of the AP is overcome and injury develops are unknown. Although primarily a soluble circulating protein, fH can also bind to tissues in a manner dependent on the carboxyl-terminal domain containing short consensus repeats 19 and 20. We examined the role of fH in CAIA by blocking its binding to tissues through administration of a recombinant negative inhibitor containing short consensus repeats 19 and 20 (rfH19-20), which impairs fH function and amplifies surface AP activation in vitro. Administration of rfH19-20, but not control rfH3-5, significantly worsened clinical disease activity, histopathologic injury, and C3 deposition in the synovium and cartilage in wild-type and fH(+/-) mice. In vitro studies demonstrated that rfH19-20 increased complement activation on cartilage extracts and injured fibroblast-like synoviocytes, two major targets of complement deposition in the joint. We conclude that endogenous fH makes a significant contribution to inhibition of the AP in CAIA through binding to sites of immune complex formation and complement activation.

The synovium in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease targeting multiple joints. The synovium is the primary site of the inflammatory process, which if untreated leads to irreversible damage to the adjacent cartilage and bone. It is now well established that autoantibodies that are characteristic of RA, including rheumatoid factor (RF) and anti-citrulluninated protein antibodies (ACPA), are present before clinical disease onset. Studies in both humans and animal models are beginning to provide new insights into how this asymptomatic autoimmunity evolves into an inflammatory process that is localized in the synovium.Once RA synovitis established, a number of amplification mechanisms serve to sustain the process leading to the persistence of the disease. These mechanisms include engagement of the resident mesenchymal cells and the establishment of ectopic lymphoid structures in the synovium, although the relationship between these lymphoid structures and the presence of RA autoantibodies remains unclear.An enhanced understanding of the mechanisms that initiate and sustain RA synovitis offers unprecedented opportunities for therapeutics, and ultimately prevention strategies.

KRN/I-Ag7 mouse arthritis is independent of complement C3

BACKGROUND

KRN/I-A(g7) (KxB/N) is a mouse model of inflammatory arthritis, which resembles human rheumatoid arthritis. Arthritis in these animals is caused by autoreactivity to a ubiquitously expressed autoantigen, glucose-6 phosphate isomerase. Tolerance is broken at both the T cell and B cell level. The sera from KRN/I-A(g7) mice can induce mouse arthritis in healthy mice. Complement components of the alternative complement pathway, including C3, have been shown to be required in induction of mouse arthritis by serum transfer.

METHODS

We have bred KRN/I-A(g7) mice onto a C3-deficient background and followed cohorts for the spontaneous appearance of arthritis. We have also transferred KxB/N serum to B6.I-A ( g7 ) recipients.

RESULTS

C3-deficient KRN/I-A(g7) mice spontaneously developed severe, destructive arthritis, comparable to that seen in C3-intact KRN/I-A(g7) mice. However, serum transfer experiments confirmed the strong requirement for C3 in the passive model.

CONCLUSION

The pathogenesis of spontaneous KRN/I-A(g7) arthritis can largely proceed by complement-independent pathways and must have pathology effector mechanisms in addition to those seen in the passive serum transfer model.

Immune cell-derived c3 is required for autoimmune diabetes induced by multiple low doses of streptozotocin

OBJECTIVE

The complement system contributes to autoimmune injury, but its involvement in promoting the development of autoimmune diabetes is unknown. In this study, our goal was to ascertain the role of complement C3 in autoimmune diabetes.

RESEARCH DESIGN AND METHODS

Susceptibility to diabetes development after multiple low-dose streptozotocin treatment in wild-type (WT) and C3-deficient mice was analyzed. Bone marrow chimeras, luminex, and quantitative reverse transcription PCR assays were performed to evaluate the phenotypic and immunologic impact of C3 in the development of this diabetes model.

RESULTS

Coincident with the induced elevations in blood glucose levels, we documented alternative pathway complement component gene expression within the islets of the diabetic WT mice. When we repeated the experiments with C3-deficient mice, we observed complete resistance to disease, as assessed by the absence of histologic insulitis and the absence of T-cell reactivity to islet antigens. Studies of WT chimeras bearing C3-deficient bone marrow cells showed that bone marrow cell-derived C3, and not serum C3, is involved in the induction of diabetes in this model.

CONCLUSIONS

The data reveal a key role for immune cell-derived C3 in the pathogenesis of murine multiple low-dose streptozotocin-induced diabetes and support the concept that immune cell mediated diabetes is in part complement-dependent.

The role of antibodies in inflammatory arthritis

Inflammatory arthritis presents in a variety of diseases, from rheumatoid arthritis to hepatitis. Antibodies to autoantigens or to microbial constituents are commonly associated with these conditions. In some cases, the antibodies have diagnostic and prognostic relevance. It cannot as yet be determined definitively that any of them mediate joint damage, although the evidence from animal models indicates that this mechanism is likely. The purpose of this article is to give an overview of the spectrum of antibodies found in a variety of inflammatory arthritides. The relevant animal models are also discussed.

Neutrophils in a mouse model of autoantibody-mediated arthritis: critical producers of Fc receptor gamma, the receptor for C5a, and lymphocyte function-associated antigen 1

OBJECTIVE

Neutrophils represent a prominent component of inflammatory joint effusions and are required for synovial inflammation in mouse models, but the mechanisms are poorly understood. In this study, we developed a system with which to test the importance of the production of specific factors by neutrophils in a mouse model of arthritis.

METHODS

Neutrophil-deficient Gfi-1(-/-) mice were administered sublethal doses of radiation and were then engrafted with donor bone marrow cells (BMCs), which resulted in the production of mature neutrophils within 2 weeks. By reconstituting with BMCs from mice lacking selected proinflammatory factors, we generated mice that specifically lacked these factors on their neutrophils. Arthritis was initiated by transfer of K/BxN serum to identify the role of defined neutrophil factors on the incidence and severity of arthritis.

RESULTS

Neutrophils lacking the signaling chain of stimulatory Fc receptors (FcRgamma(-/-)) were unable to elicit arthritis, but neutrophils lacking FcgammaRIII still did so. Neutrophils lacking the chemotactic or adhesion receptor C5a receptor (C5aR) or CD11a/lymphocyte function-associated antigen 1 (LFA-1) also failed to initiate arthritis but could enter joints in which inflammation had been initiated by wild-type neutrophils. Neutrophils unable to produce interleukin-1alpha (IL-1alpha) and IL-1beta (IL-1alpha/beta(-/-)) or leukotrienes (5-lipoxygenase [5-LOX(-/-)]) produced arthritis of intermediate severity. The inability of neutrophils to make tumor necrosis factor or to express receptors for tumor necrosis factor or IL-1 had no effect on arthritis.

CONCLUSION

A novel transfer system was developed to identify neutrophil production of FcRgamma, C5aR, and CD11a/LFA-1 as critical components of autoantibody-mediated arthritis. Neutrophil production of IL-1 and leukotriene B(4) likely contributes to inflammation but is not essential. Molecular requirements for neutrophil influx into joints become more permissive after inflammation is initiated.

Chondroitin sulfate and abnormal contact system in rheumatoid arthritis

Rheumatoid arthritis (RA) is a heterogeneous autoimmune disease that affects 1% of the population worldwide. In the K/BxN mouse model of RA, autoantibodies specific for glucose-6-phosphate isomerase (GPI) from these mice can transfer joint-specific inflammation to normal mice. The binding of GPI/autoantibody to the cartilage surface is a prerequisite for autoantibody-induced joint-specific inflammation in the mouse model. Chondroitin sulfate (CS) on cartilage surface is the long sought high-affinity receptor for GPI. The binding affinity and structural differences between mouse paw/ankle CS and knee/elbow CS correlate with the distal to proximal disease severity in these joints. The data presented in this chapter indicate that autoantigen/autoantibodies in blood circulation activate contact system to produce vasodilators to allow immune complex, protein aggregates, and other plasma proteins to get into the joints. Cartilage surface CS binds and retains autoantigen/autoantibodies. The CS/autoantigen/autoantibody complexes could induce C3a and C5a production through contact system activation. C3a and C5a trigger degranulation of mast cells, which further recruit plasma contact system and complement proteins, immune cells, and immune activation factors to facilitate joint-specific tissue destruction. Therefore, either reducing autoantibody production or inhibiting autoantibody-induced contact system activation might be effective in RA prevention.

The preclinical stages of RA: lessons from human studies and animal models

Rheumatoid arthritis (RA) is a systemic autoimmune disorder based in the synovium of peripheral joints. Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) are autoantibodies detectable in the majority of patients, with the latter being highly specific for RA. Retrospective studies utilizing preclinical serum samples have demonstrated that RF and ACPAs are detectable in the serum of RA patients months to years before disease onset. Moreover, a close association between ACPAs, smoking, and disease-predisposing HLA-DRB1 alleles has been identified, suggesting that these risk factors may converge to precipitate autoantibody-positive RA. Animal models of RA have added considerable information regarding the immune events that precede joint inflammation. These models have demonstrated that autoantibodies to ubiquitous antigens can directly precipitate chronic organ-specific inflammation centred in the joint. Furthermore, it has recently been possible to demonstrate a role for ACPAs in the animal models of RA. The major challenge currently is to develop a robust predictive model for RA onset, identifying the factors that serve to initiate, amplify, and mature the immune responses towards citrullinated autoantigens. Recent data from a high-risk population of RA family members indicate that the nature and specificity of the ACPA response in healthy individuals differs considerably from that in RA patients, and support the concept that this autoimmune response evolves over time and leads to the onset of clinically detectable synovitis. Ultimately, the availability of data from prospective studies of RA onset will allow for novel strategies that can potentially prevent disease in high-risk individuals.

Antigen-specific tolerogenic and immunomodulatory strategies for the treatment of autoimmune arthritis

OBJECTIVES

To review various antigen-specific tolerogenic and immunomodulatory approaches for arthritis in animal models and patients in regard to their efficacy, mechanisms of action, and limitations.

METHODS

We reviewed the published literature in Medline (PubMed) on the induction of antigen-specific tolerance and its effect on autoimmune arthritis, as well as the recent work on B-cell-mediated tolerance from our laboratory. The prominent key words used in different combinations included arthritis, autoimmunity, immunotherapy, innate immunity, tolerance, treatment, and rheumatoid arthritis (RA). Although this search spanned the years 1975 to 2007, the majority of the short-listed articles belonged to the period 1990 to 2007. The relevant primary as well as cross-referenced articles were then collected from links within PubMed and reviewed.

RESULTS

Antigen-specific tolerance has been successful in the prevention and/or treatment of arthritis in animal models. The administration of soluble native antigen or an altered peptide ligand intravenously, orally, or nasally, and the delivery of the DNA encoding a particular antigen by gene therapy have been the mainstay of immunomodulation. Recently, the methods for in vitro expansion of CD4+CD25+ regulatory T-cells have been optimized. Furthermore, interleukin-17 has emerged as a promising new therapeutic target in arthritis. However, in RA patients, non-antigen-specific therapeutic approaches have been much more successful than antigen-specific tolerogenic regimens.

CONCLUSION

An antigen-specific treatment against autoimmune arthritis is still elusive. However, insights into newly emerging mechanisms of disease pathogenesis provide hope for the development of effective and safe immunotherapeutic strategies in the near future.

Adenovirus-mediated gene transfer of adiponectin reduces the severity of collagen-induced arthritis in mice

Adiponectin (APN) is a hormone released by adipose tissue with anti-inflammatory properties. The purpose of this study was to examine the therapeutic effects of systemic delivery of APN in murine arthritis model. Collagen-induced arthritis (CIA) was induced in male DBA1/J mice, and adenoviral vectors encoding human APN (Ad-APN) or beta-galactosidase (Ad-beta-gal) as control were injected either before or during arthritis progression. Systemic APN delivery at both time points significantly decreased clinical disease activity scores of CIA. In addition, APN treatment before arthritis progression significantly decreased histological scores of inflammation and cartilage damage, bone erosion, and mRNA levels of pro-inflammatory cytokines in the joints, without altering serum anti-collagen antibodies levels. Immunohistochemical staining showed significant inhibition of complement C1q and C3 deposition in the joints of Ad-APN infected CIA mice. These results provide novel evidence that systemic APN delivery prevents inflammation and joint destruction in murine arthritis model.