Human, viral or mutant human IL-10 expressed after local adenovirus-mediated gene transfer are equally effective in ameliorating disease pathology in a rabbit knee model of antigen-induced arthritis

IL-10 Paradoxically Promotes Autoimmune Neuropathy through S1PR1-Dependent CD4+ T Cell Migration

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a debilitating condition caused by autoimmune demyelination of peripheral nerves. CIDP is associated with increased IL-10, a cytokine with well-described anti-inflammatory effects. However, the role of IL-10 in CIDP is unclear. In this study, we demonstrate that IL-10 paradoxically exacerbates autoimmunity against peripheral nerves. In IL-10-deficient mice, protection from neuropathy was associated with an accrual of highly activated CD4+ T cells in draining lymph nodes and absence of infiltrating immune cells in peripheral nerves. Accumulated CD4+ T cells in draining lymph nodes of IL-10-deficient mice expressed lower sphingosine-1-phosphate receptor 1 (S1pr1), a protein important in lymphocyte egress. Additionally, IL-10 stimulation in vitro induced S1pr1 expression in lymph node cells in a STAT3-dependent manner. Together, these results delineate a novel mechanism in which IL-10-induced STAT3 increases S1pr1 expression and CD4+ T cell migration to accelerate T cell-mediated destruction of peripheral nerves.

The therapeutic potential of interleukin-10 in neuroimmune diseases

Neuroimmune diseases have diverse symptoms and etiologies but all involve pathological inflammation that affects normal central nervous system signaling. Critically, many neuroimmune diseases also involve insufficient signaling/bioavailability of interleukin-10 (IL-10). IL-10 is a potent anti-inflammatory cytokine released by immune cells and glia, which drives the regulation of a variety of anti-inflammatory processes. This review will focus on the signaling pathways and function of IL-10, the current evidence for insufficiencies in IL-10 signaling/bioavailability in neuroimmune diseases, as well as the implications for IL-10-based therapies to treating such problems. We will review in detail four pathologies as examples of the common etiologies of such disease states, namely neuropathic pain (nerve trauma), osteoarthritis (peripheral inflammation), Parkinson's disease (neurodegeneration), and multiple sclerosis (autoimmune). A number of methods to increase IL-10 have been developed (e.g. protein administration, viral vectors, naked plasmid DNA, plasmid DNA packaged in polymers to enhance their uptake into target cells, and adenosine 2A agonists), which will also be discussed. In general, IL-10-based therapies have been effective at treating both the symptoms and pathology associated with various neuroimmune diseases, with more sophisticated gene therapy-based methods producing sustained therapeutic effects lasting for several months following a single injection. These exciting results have resulted in IL-10-targeted therapeutics being positioned for upcoming clinical trials for treating neuroimmune diseases, including neuropathic pain. Although further research is necessary to determine the full range of effects associated with IL-10-based therapy, evidence suggests IL-10 may be an invaluable target for the treatment of neuroimmune disease. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.

Targeting of viral interleukin-10 with an antibody fragment specific to damaged arthritic cartilage improves its therapeutic potency

INTRODUCTION

We previously demonstrated that a single-chain fragment variable (scFv) specific to collagen type II (CII) posttranslationally modified by reactive oxygen species (ROS) can be used to target anti-inflammatory therapeutics specifically to inflamed arthritic joints. The objective of the present study was to demonstrate the superior efficacy of anti-inflammatory cytokines when targeted to inflamed arthritic joints by the anti-ROS modified CII (anti-ROS-CII) scFv in a mouse model of arthritis.

METHODS

Viral interleukin-10 (vIL-10) was fused to anti-ROS-CII scFv (1-11E) with a matrix-metalloproteinase (MMP) cleavable linker to create 1-11E/vIL-10 fusion. Binding of 1-11E/vIL-10 to ROS-CII was determined by enzyme-linked immunosorbent assay (ELISA), Western blotting, and immune-staining of arthritic cartilage, whereas vIL-10 bioactivity was evaluated in vitro by using an MC-9 cell-proliferation assay. Specific in vivo localization and therapeutic efficacy of 1-11E/vIL-10 was tested in the mouse model of antigen-induced arthritis.

RESULTS

1-11E/vIL-10 bound specifically to ROS-CII and to damaged arthritic cartilage. Interestingly, the in vitro vIL-10 activity in the fusion protein was observed only after cleavage with MMP-1. When systemically administered to arthritic mice, 1-11E/vIL-10 localized specifically to the arthritic knee, with peak accumulation observed after 3 days. Moreover, 1-11E/vIL-10 reduced inflammation significantly quicker than vIL-10 fused to the control anti-hen egg lysozyme scFv (C7/vIL10).

CONCLUSIONS

Targeted delivery of anti-inflammatory cytokines potentiates their anti-arthritic action in a mouse model of arthritis. Our results further support the hypothesis that targeting biotherapeutics to arthritic joints may be extended to include anti-inflammatory cytokines that lack efficacy when administered systemically.

Regulation of osteoarthritis-associated key mediators by TNFα and IL-10: effects of IL-10 overexpression in human synovial fibroblasts and a synovial cell line

Synovial fibroblasts (SF) contribute to the pathogenesis of osteoarthritis (OA), but the effects of intra-articular cytokines on SF are not completely understood. The aim of this study was to characterize the interplay between tumor necrosis factor (TNF)α and the anti-inflammatory interleukin (IL)-10. Non-immortalized human SF and SF of the human cell line K4IM were stimulated with recombinant TNFα, IL-10, or TNFα + IL-10 (10 ng/ml each) for 24 h or transduced with an adenoviral vector overexpressing human IL-10 (hIL-10) and subsequently treated with 10 ng/ml TNFα for 24 h. Effects on the gene expression and protein synthesis of IL-6, IL-10, matrix metalloproteinases (MMP)-1, -3, type I collagen, β1-integrin, and CD44 were investigated via real-time detection polymerase chain reaction, immunofluorescence labeling, flow cytometry, and Western blotting. IL-10 release by transduced SF was confirmed with enzyme-linked immunosorbent assay. Both cell populations were activated by TNFα and by TNFα + IL-10, increasing their gene expression and protein synthesis of IL-6, IL-10, MMP-1, and MMP-3 and altering the synthesis of type I collagen, β1-integrin, and CD44. hIL-10 overexpression greatly elevated the gene expression and protein synthesis of IL-10. However, transduction did not significantly affect the gene expression of IL-6, MMP-1, and MMP-3 in SF. The increased expression of pro-inflammatory and catabolic mediators in TNFα-activated SF indicates their role in OA pathogenesis, suggesting they are a potential therapeutic target. Although the vigorousness of the responses of non-immortalized SF and K4IM clearly differ, the K4IM cell line seems to be a suitable model for non-immortalized human SF.

IL-10 encoded by viruses: a remarkable example of independent acquisition of a cellular gene by viruses and its subsequent evolution in the viral genome

Many viruses have evolved strategies to deregulate the host immune system. These strategies include mechanisms to subvert or recruit the host cytokine network. IL-10 is a pleiotropic cytokine that has both immunostimulatory and immunosuppressive properties. However, its key features relate mainly to its capacity to exert potent immunosuppressive effects. Several viruses have been shown to upregulate the expression of cellular IL-10 (cIL-10) with, in some cases, enhancement of infection by suppression of immune functions. Other viruses encode functional orthologues of cIL-10, called viral IL-10s (vIL-10s). The present review is devoted to these virokines. To date, vIL-10 orthologues have been reported for 12 members of the family Herpesviridae, two members of the family Alloherpesviridae and seven members of the family Poxviridae. Study of vIL-10s demonstrated several interesting aspects on the origin and the evolution of these viral genes, e.g. the existence of multiple (potentially up to nine) independent gene acquisition events at different times during evolution, viral gene acquisition resulting from recombination with cellular genomic DNA or cDNA derived from cellular mRNA and the evolution of cellular sequence in the viral genome to restrict the biological activities of the viral orthologues to those beneficial for the virus life cycle. Here, various aspects of the vIL-10s described to date are reviewed, including their genetic organization, protein structure, origin, evolution, biological properties and potential in applied research.

Interleukin-10 produced by B cells is crucial for the suppression of Th17/Th1 responses, induction of T regulatory type 1 cells and reduction of collagen-induced arthritis

INTRODUCTION

Interleukin-10 (IL-10) producing B cells, also known as regulatory B (Breg) cells, play a key role in controlling autoimmunity. Our laboratory and others have demonstrated a pivotal role for Bregs in rheumatological disorders, including experimental models of arthritis and lupus. The aim of this study was to identify the role of endogenous IL-10 secreting B cells in vivo in controlling the induction and disease progression of collagen-induced arthritis (CIA).

METHODS

We generated chimeric mice that had IL-10 knocked-out specifically in the B cell population. These mice were compared with wild-type (WT) B cell chimeric mice for their susceptibility to CIA.

RESULTS

Here we report that chimeric mice specifically lacking IL-10 producing B cells (IL-10-/- B cell) developed an exacerbated CIA compared to chimeric wild type B cell (WT B cell) mice. A marked increase in inflammatory Th1 and Th17 cells were detected in IL-10-/-B cell mice compared to WT B cell mice. Furthermore, there was a reduction in IL-10 secreting CD4+ Tr1 cells in these animals.

CONCLUSIONS

IL-10 producing B cells restrain inflammation by promoting differentiation of immuno-regulatory over pro-inflammatory T cells and, hence, act to maintain tolerance.

Cytokine homologs of human gammaherpesviruses

Gammaherpesviruses such as Epstein-Barr virus (EBV, human herpesvirus 4) and Kaposi sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) establish lifelong infection in the host. To further this lifestyle, they encode homologs of cellular cytokines and cytokine receptors with the overarching goal to escape from or to blunt host antiviral defenses. EBV encodes mimics of human interleukin (hIL)-10 and a G protein-coupled receptor protein with sequence similarity to CXCR, whereas KSHV encodes homologs of hIL-6, 3 CC chemokine ligands, and a G protein-coupled receptor with sequence similarity to IL8 receptor alpha. This review focuses on the EBV IL-10 homolog and the KSHV IL-6 homolog with respect to virus biology and pathogenesis of the virus-associated diseases.

Gene Therapy for Cartilage Repair

The concept of using gene transfer strategies for cartilage repair originates from the idea of transferring genes encoding therapeutic factors into the repair tissue, resulting in a temporarily and spatially defined delivery of therapeutic molecules to sites of cartilage damage. This review focuses on the potential benefits of using gene therapy approaches for the repair of articular cartilage and meniscal fibrocartilage, including articular cartilage defects resulting from acute trauma, osteochondritis dissecans, osteonecrosis, and osteoarthritis. Possible applications for meniscal repair comprise meniscal lesions, meniscal sutures, and meniscal transplantation. Recent studies in both small and large animal models have demonstrated the applicability of gene-based approaches for cartilage repair. Chondrogenic pathways were stimulated in the repair tissue and in osteoarthritic cartilage using genes for polypeptide growth factors and transcription factors. Although encouraging data have been generated, a successful translation of gene therapy for cartilage repair will require an ongoing combined effort of orthopedic surgeons and of basic scientists.

Antigen-induced arthritis in rabbits: a comparative study between high-resolution ultrasound and contrast-enhanced ultrasound and pathologic findings

The objective of this study was to explore the feasibility and value of high-resolution ultrasound and contrast-enhanced ultrasound in evaluation of synovitis in rabbit knee joint in antigen-induced arthritis (AIA). Thirty-six rabbits were divided into three groups, each injected with different doses of ovalbumin (OVA) into the right knee joint. On week 1 and 4, 6 randomly selected in each group were killed. Each knee joint undergone the high-resolution ultrasound to measure capsule thickness and contrast-enhanced ultrasound to measure synovium thickness. The results from the ultrasound examinations were compared with those of pathologic examinations. Different OVA doses resulted in different modeling success rate, different pathological synovitis score, and different capsule and synovium thickness measured by ultrasound. The diagnostic accuracy of synovitis by ultrasound was high. The ultrasound measurement revealed that the capsule thickness on week 4 was lessened than that on week 1, while the synovial thickness on week 4 was greater than that on week 1. Both the joint capsule and synovium thickness measured by ultrasound were significantly and positively correlated to the pathologic synovitis score (P < 0.05). The synovial thickness on week 4 is more correlated to the synovitis score than the capsule thickness, rather than that on week 1. Injection of OVA of different doses results in different modeling success rate and synovitis severity. The high-resolution ultrasound and contrast-enhanced ultrasound can be used to determine whether the AIA was made successfully and evaluate the synovitis severity. In chronic inflammatory phase, the contrast-enhanced ultrasound has better effect.

Endogenous IL-10 regulates sepsis-induced thymic apoptosis and improves survival in septic IL-10 null mice

Recent studies have shown that increased lymphocyte apoptosis contributes to sepsis-induced mortality. Furthermore, studies have demonstrated that IL-10 can suppress lymphocyte apoptosis, in part, by upregulating Bcl-2 expression and interfering with activation induced cell death. We have previously shown that intrathymic delivery of IL-10 with an adenoviral vector in wild-type mice significantly improves outcome to sepsis. Presently, we investigated the role of endogenous IL-10 expression on thymocyte apoptosis and outcome in IL-10 null mice subject to induction of generalized polymicrobial peritonitis via cecal ligation and puncture. Compared to wild-type C57BL/6 mice, IL-10 null mice demonstrated increased mortality and enhanced lymphocyte apoptosis. Intrathymic injection with an adenoviral vector expressing human IL-10 prior to cecal ligation and puncture in IL-10 null mice significantly improved outcome and decreased thymic caspase-3 activity. Furthermore, plasma concentrations of IL-6 were also significantly reduced in IL-10 null mice treated with the IL-10 expressing adenovirus. In contrast, injection of a control adenovirus did not improve outcome in IL-10 null mice, nor was caspase-3 activity reduced. Thus, local thymic expression of IL-10 not only improves outcome but also reduces local tissue apoptosis and caspase-3 activity, and appears to attenuate the systemic proinflammatory cytokine response.

Association of interleukin-6 and interleukin-10 genotypes with radiographic damage in rheumatoid arthritis is dependent on autoantibody status

Objective

Recent evidence has highlighted a major genetic contribution to radiographic damage in rheumatoid arthritis (RA). The objective of this study was to determine whether genetic variants in the loci for interleukin-1 (IL-1), IL-6, IL-10, protein tyrosine phosphatase N22 (PTPN22), and selenoprotein S are associated with radiographic damage.

Methods

Modified Larsen scores of radiographic damage were determined in a cross-sectional population of patients with RA (n = 964). Rheumatoid factor (RF) and anti–cyclic citrullinated peptide (anti-CCP) were also assayed. The Kruskal-Wallis nonparametric test was used to compare median radiographic damage scores across genotype groups, followed by the Cuzick nonparametric test for trend to assess gene-dose effects.

Results

An allele-dose association of IL-6 −174G with increasing radiographic damage was present (P = 0.005), but only in patients who were RF positive (P = 0.004) or anti-CCP positive (P = 0.01). Patients with the IL-10 −592CC genotype had more extensive radiographic damage than did those with the AC or AA genotype (P = 0.006), but this was observed only among patients who were RF negative (P = 0.002) or anti-CCP negative (P = 0.002). However, RF status and anti-CCP status were not associated with the IL-6 or IL-10 genotype. No other genetic associations were detected, apart from a marginal association of PTPN22 +1858T with increased radiographic damage.

Conclusion

The reported associations of IL-6 −174G with high IL-6 production and IL-10 −592 with low IL-10 production and our own results support a role of genetically determined dysregulated cytokine production in disease severity. The lack of association of these genotypes with RF and anti-CCP antibody status suggests that they act downstream of autoantibody production. We conclude that IL-6 and IL-10 genotypes may be useful in predicting disease severity in autoantibody-positive and autoantibody-negative patients, respectively.