Treatment of rheumatoid arthritis with IL-1 inhibitors

Immunomodulatory agents for COVID-19 treatment: possible mechanism of action and immunopathology features

The novel coronavirus pandemic has emerged as one of the significant medical-health challenges of the current century. The World Health Organization has named this new virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the first detection of SARS-CoV-2 in November 2019 in Wuhan, China, physicians, researchers, and others have made it their top priority to find drugs and cures that can effectively treat patients and reduce mortality rates. The symptoms of Coronavirus Disease 2019 (COVID-19) include fever, dry cough, body aches, and anosmia. Various therapeutic compounds have been investigated and applied to mitigate the symptoms in COVID-19 patients and cure the disease. Degenerative virus analyses of the infection incidence and COVID-19 have demonstrated that SARS-CoV-2 penetrates the pulmonary alveoli's endothelial cells through Angiotensin-Converting Enzyme 2 (ACE2) receptors on the membrane, stimulates various signaling pathways and causes excessive secretion of cytokines. The continuous triggering of the innate and acquired immune system, as well as the overproduction of pro-inflammatory factors, cause a severe condition in the COVID-19 patients, which is called "cytokine storm". It can lead to acute respiratory distress syndrome (ARDS) in critical patients. Severe and critical COVID-19 cases demand oxygen therapy and mechanical ventilator support. Various drugs, including immunomodulatory and immunosuppressive agents (e.g., monoclonal antibodies (mAbs) and interleukin antagonists) have been utilized in clinical trials. However, the studies and clinical trials have documented diverging findings, which seem to be due to the differences in these drugs' possible mechanisms of action. These drugs' mechanism of action generally includes suppressing or modulating the immune system, preventing the development of cytokine storm via various signaling pathways, and enhancing the blood vessels' diameter in the lungs. In this review article, multiple medications from different drug families are discussed, and their possible mechanisms of action are also described.

Comprehensive microRNA profiling reveals potential augmentation of the IL1 pathway in rheumatic heart valve disease

BACKGROUND

Valvular heart disease is a leading cause of cardiovascular mortality, especially in China. More than a half of valvular heart diseases are caused by acute rheumatic fever. microRNA is involved in many physiological and pathological processes. However, the miRNA profile of the rheumatic valvular heart disease is unknown. This research is to discuss microRNAs and their target gene pathways involved in rheumatic heart valve disease.

METHODS

Serum miRNA from one healthy individual and four rheumatic heart disease patients were sequenced. Specific differentially expressed miRNAs were quantified by Q-PCR in 40 patients, with 20 low-to-moderate rheumatic mitral valve stenosis patients and 20 severe mitral valve stenosis patients. The target relationship between certain miRNA and predicted target genes were analysis by Luciferase reporter assay. The IL-1β and IL1R1 expression levels were analyzed by immunohistochemistry and western blot in the mitral valve from surgery of mitral valve replacement.

RESULTS

The results showed that 13 and 91 miRNAs were commonly upregulated or downregulated in all four patients. Nine miRNAs, 1 upregulated and 8 downregulated, that had a similar fold change in all 4 patients were selected for quantitative PCR verification. The results showed similar results from miRNA sequencing. Within these 9 tested miRNAs, hsa-miR-205-3p and hsa-miR-3909 showed a low degree of dispersion between the members of each group. Hsa miR-205-3p and hsa-miR-3909 were predicted to target the 3'UTR of IL-1β and IL1R1 respectively. This was verified by luciferase reporter assays. Immunohistochemistry and Western blot results showed that the mitral valve from rheumatic valve heart disease showed higher levels of IL- 1β and IL1R1 expression compared with congenital heart valve disease. This suggested a difference between rheumatic heart valve disease and other types of heart valve diseases, with more inflammatory responses in the former.

CONCLUSION

In the present study, by next generation sequencing of miRNAs, it was revealed that interleukin 1β and interleukin 1 receptor 1 was involved in rheumatic heart diseases. And this is useful for diagnosis and understanding of mechanism of rheumatic heart disease.

Mesenchymal stem cells ameliorate experimental arthritis via expression of interleukin-1 receptor antagonist

Human bone marrow-derived mesenchymal stem cells (MSCs) have been observed to inhibit arthritis in experimental animal models such as collagen-induced arthritis. However, the exact anti-inflammatory mechanisms remain poorly understood. Interleukin-1 receptor antagonist (IL-1Ra) is an anti-inflammatory cytokine produced by immune and stromal cells. We postulated that MSCs could produce IL-1Ra and attenuate experimental arthritis. In this study, 5x106 MSCs were injected into the peritoneal cavity of IL-1Ra knockout (IL-1RaKO) mice. MSCs reduced the severity of the arthritis by histology and decreased pro-inflammatory cytokine levels in IL-1RaKO mice. The ratio of splenic T helper 17 (Th17) cells to regulatory T cells (Treg) was significantly decreased in MSC-injected IL-1RaKO mice. Purified splenic CD4+ T cells from mice in each of the treatment groups were cultured under Th17 polarizing conditions and analyzed by flow cytometry. Less expansion of the Th17 population was observed in the MSC-treated group. Interestingly, MSCs expressed inducible IL-1Ra against inflammatory environmental stimuli. Human recombinant IL-1Ra could suppress Th17 cells differentiation under Th17 polarizing conditions. These results indicate that IL-1Ra expressed by MSCs can inhibit Th17 polarization and decrease the immune response in IL-1RaKO mice. Therefore, MSC-derived IL-1Ra may inhibit inflammation in IL-1RaKO mice via effects on Th17 differentiation.

Cytokine and Growth Factor Concentrations in Canine Autologous Conditioned Serum

OBJECTIVE

To compare cytokine and growth factor concentrations in canine autologous conditioned serum (ACS) to canine plasma.

STUDY DESIGN

Experimental in vivo study.

ANIMALS

Client-owned, adult dogs (n=22).

METHODS

Blood collected from 16 medium to large breed dogs was used to produce ACS (Orthokine(®) vet irap 10 syringes) and citrated plasma (control). Canine-specific ELISA assays were run per manufacturers' instructions for interleukin (IL)-10, IL-4, tumor necrosis factor (TNF)-α, insulin-like growth factor (IGF)-1, fibroblast growth factor (FGF)-2, transforming growth factor (TGF)-β1, IL-1β, and interleukin-1 receptor antagonist (IL-1ra). Serum, in addition to plasma and ACS, was collected from an additional 6 dogs for TNF-α, IL-1β, and IL-1ra analysis (total of 22 dogs). Data were analyzed for differences in each cytokine concentration using pairwise comparisons between ACS, plasma, and serum using Wilcoxon signed-rank tests. Significance was set at P<.05.

RESULTS

There was a large variability in growth factor and cytokine concentrations in ACS and plasma for individual dogs. There were no significant differences in IL-10, TNF-α, IGF-1, FGF-2, and TGF-β1 concentrations between ACS, plasma, and serum. The IL-1β concentrations in ACS (median, range 46.3 pg/mL, 0-828.8) and IL-4 (0.0 pg/mL, 0-244.1) were significantly higher than plasma (36.6 pg/mL, 0-657.1 and 0.0 pg/mL, 0-0, respectively). The IL-1ra concentration in ACS (median, range 3,458.9 pg/mL, 1,243.1-12,089.0) was significantly higher than plasma (692.3 pg/mL, 422.5-1,475.6). The IL-1ra:IL-1β ratio in ACS was significantly higher than plasma (39.9 vs. 7.2).

CONCLUSION

IL-1ra concentrations in canine ACS were comparable to those published for people and horses and pro-inflammatory cytokines remained low in canine ACS.

Aryl hydrocarbon receptor antagonism and its role in rheumatoid arthritis

Although rheumatoid arthritis (RA) is the most common autoimmune disease, affecting approximately 1% of the population worldwide, its pathogenic mechanisms are poorly understood. Tobacco smoke, an environmental risk factor for RA, contains several ligands of aryl hydrocarbon receptor (Ahr), also known as dioxin receptor. Ahr plays critical roles in the immune system. We previously demonstrated that Ahr in helper T-cells contributes to development of collagen-induced arthritis, a mouse model of RA. Other studies have shown that cigarette smoke condensate and pure Ahr ligands exacerbate RA by altering bone metabolism and inducing proinflammatory responses in fibroblast-like synoviocytes. Consistent with these findings, several Ahr antagonists such as α-naphthoflavone, resveratrol, and GNF351 reverse the effect of Ahr ligands in RA pathogenesis. In this review, we summarize the current knowledge of Ahr function in the immune system and the potential clinical benefits of Ahr antagonism in treating RA.

Modern anti-cytokine therapy of autoimmune diseases

The emergence of genetically engineered biological agents opened new prospects in the treatment of autoimmune and inflammatory diseases. Cytokines responsible for regulation of a wide range of processes during development of the normal immune response are among the most successful therapeutic targets. Studies carried out in recent decades and accompanied by rapid development of biotechnology have promoted establishing in detail the role and place of cytokines in autoimmune and inflammatory pathologies. Nevertheless, mechanisms that underlie anti-cytokine therapy are still not fully understood. This review examines the role of such cytokines as TNF, IL-1, and IL-6 in the development of inflammatory processes and the action mechanisms of their inhibitors.

scAAVIL-1ra dosing trial in a large animal model and validation of long-term expression with repeat administration for osteoarthritis therapy

A gene therapeutic approach to treat osteoarthritis (OA) appears to be on the horizon for millions of people who suffer from this disease. Previously we described optimization of a scAAVIL-1ra gene therapeutic vector and initially tested this in an equine model verifying long-term intrasynovial IL-1ra protein at therapeutic levels. Using this vector, we carried out a dosing trial in six horses to verify protein levels and establish a dose that would express relevant levels of therapeutic protein for extended periods of time (8 months). A novel arthroscopic procedure used to detect green fluorescence protein (GFP) fluorescence intrasynovially confirmed successful transduction of the scAAVGFP vector in both the synovial and cartilage tissues. No evidence of intra-articular toxicity was detected. Immune responses to vector revealed development of neutralizing antibodies (Nabs) within 2 weeks of administration, which persisted for the duration of the study but did not lower protein expression intra-articularly. Re-dosing with a different serotype to attain therapeutic levels of protein confirmed establishment of successful transduction. This is the first study in an equine model to establish a dosing/redosing protocol, as well as examine the Nab response to capsid and supports further clinical investigation to determine the clinical efficacy of scAAVIL-1ra to treat OA.

Periodontal disease and rheumatoid arthritis: a systematic review

This systematic review considers the evidence available for a relationship between periodontal disease and rheumatoid arthritis. MEDLINE/PubMed, CINAHL, DOSS, Embase, Scopus, Web of Knowledge, MedNar, and ProQuest Theses and Dissertations were searched from the inception of the database until June 2012 for any quantitative studies that examined the association between periodontal disease and rheumatoid arthritis. Nineteen studies met our inclusion criteria. Good evidence was found to support an association between these conditions with regard to tooth loss, clinical attachment levels, and erythrocyte sedimentation rates. Moderate evidence was noted for C-reactive protein and interleukin-1β. Some evidence for a positive outcome of periodontal treatment on the clinical features of rheumatoid arthritis was noted. These results provide moderate evidence based on biochemical markers and stronger evidence with regard to clinical parameters that common risk factors or common pathologic processes may be responsible for an association between rheumatoid arthritis and periodontal disease. Further studies are required to fully explore both the biochemical processes and clinical relationships between these 2 chronic inflammatory conditions. There is a need to move from case-control studies to more rigorous studies using well-defined populations and well-defined biochemical and clinical outcomes as the primary outcome measures with consideration of potential confounding factors.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Delivery of biologically active anti-inflammatory cytokines IL-10 and IL-1ra in vivo by the Shigella type III secretion apparatus

Pathogenicity of many Gram-negative bacteria relies on a type III secretion (T3S) apparatus, which is used for delivery of bacterial effectors into the host cell cytoplasm allowing the bacteria to manipulate host cell cytoskeleton network as well as to interfere with intracellular signaling pathways. In this study, we investigated the potential of the Shigella flexneri T3SA as an in vivo delivery system for biologically active molecules such as cytokines. The anti-inflammatory cytokines IL-10 and IL-1 receptor antagonist (IL-1ra) were genetically fused to the first 30 or 60 residues of the Shigella T3S effector IpaH9.8 or to the first 50 residues of the Yersinia enterocolitica effector YopE and the recombinant fusion proteins were expressed in S. flexneri. YopE(50)-IL-10, IpaH(60)-IL-10, and IpaH(60)-IL-1ra were efficiently secreted via the T3S apparatus of Shigella. Moreover, these recombinant proteins did not impair the invasive ability of the bacteria in vitro. In a murine model, Shigella strains expressing YopE(50)-IL-10, IpaH(60)-IL-10, and IpaH(60)-IL-1ra induced a lower mortality in mice that was associated with reduced inflammation and a restricted localization of bacteria within the lung tissues as compared with wild-type Shigella. Moreover, the level of TNF-alpha and IL-1beta mRNA were reduced in the lungs following infection by IL-10- and IL-1ra-secreting Shigella, respectively. These findings demonstrate that the Shigella T3S apparatus can deliver biologically active cytokines in vivo, thus opening new avenues for the use of attenuated bacteria to deliver proteins for immunomodulation or gene therapy purposes.

Partial protection against collagen antibody-induced arthritis in PARP-1 deficient mice

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear DNA-binding protein that participates in the regulation of DNA repair and maintenance of genomic integrity. In addition, PARP-1 has a role in several models of inflammation disease, where its absence or inactivation confers protection. The aim of this study was to analyze the impact of selective PARP-1 suppression in collagen antibody-induced arthritis. We show that PARP-1 deficiency partially reduces the severity of arthritis, although the incidence of disease was similar in control and deficient mice. Decreased clinical scores were accompanied by partial reduction of histopathological findings. Interestingly, quantitative real-time PCR and ELISA analysis revealed that the absence of PARP-1 down-regulated IL-1β and monocyte chemotactic protein 1 expression in arthritic joints whereas tumor necrosis factor-α transcription was not impaired. Our results provide evidence of the contribution of PARP-1 to the progression of arthritis and identify this protein as a potential therapeutic target for the treatment of rheumatoid arthritis.

Use of biologics in rheumatoid arthritis: Where are we going?

PURPOSE

The pharmacology, efficacy, safety, and costs of biologic agents that are approved by the Food and Drug Administration or are under review for the management of rheumatoid arthritis (RA) are discussed. Biologic therapies that are currently under investigation in early- and late-phase clinical trials are summarized at the end of this report.

SUMMARY

The use of biologic agents for the treatment of RA has significantly improved the management of this disease. Experimental and clinical studies have shown that these agents ameliorate the signs and symptoms of RA, slow radiographic progression of disease, and improve physical function and quality of life. Data also support that early initiation of therapy with these agents improves long-term outcomes. However, biologic agents are associated with adverse effects that health care providers need to recognize and manage.

CONCLUSION

Biologic agents have revolutionized the treatment of RA by reducing the signs and symptoms of RA, slowing radiographic progression of joint destruction, and improving physical function and quality of life in affected patients.

CYP7B expression and activity in fibroblast-like synoviocytes from patients with rheumatoid arthritis: regulation by proinflammatory cytokines

OBJECTIVE

The cytochrome P450 enzyme CYP7B catalyzes the conversion of dehydroepiandrosterone (DHEA) into 7alpha-hydroxy-DHEA (7alpha-OH-DHEA). This metabolite can stimulate the immune response. We previously reported that the severity of murine collagen-induced arthritis is correlated with CYP7B messenger RNA (mRNA) expression and activity in the arthritic joint. The purpose of this study was to investigate the presence of 7alpha-OH-DHEA in synovial samples and the cytokine regulation of CYP7B activity in fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA).

METHODS

The presence of 7alpha-OH-DHEA was examined in synovial biopsy tissues, synovial fluid, and serum by radioimmunoassay. The effect of cytokines on CYP7B mRNA expression and CYP7B activity in FLS was examined by determining the formation of the CYP7B enzyme product 7alpha-OH-DHEA with the use of high-performance liquid chromatography.

RESULTS

The CYP7B enzyme product 7alpha-OH-DHEA was found in synovial biopsy tissues, synovial fluid, and serum from RA patients. The proinflammatory cytokines tumor necrosis factor alpha (TNFalpha), interleukin-1alpha (IL-1alpha), IL-1beta, and IL-17 up-regulated CYP7B activity in an FLS cell line 2-10-fold. Enhanced CYP7B activity was correlated with an increase in CYP7B mRNA. The cytokine transforming growth factor beta inhibited CYP7B activity. Moreover, CYP7B activity was detected in 10 of 13 unstimulated synovial fibroblast cell lines. Stimulation with TNFalpha increased CYP7B activity in all cell lines tested.

CONCLUSION

Exposure to the proinflammatory cytokines TNFalpha, IL-1alpha, IL-1beta, and IL-17 increases CYP7B activity in synovial tissue. Increased CYP7B activity leads to higher levels of the DHEA metabolite 7alpha-OH-DHEA in synovial fluid, which may contribute to the maintenance of the chronic inflammation observed in RA patients.

Anakinra: review of recombinant human interleukin-I receptor antagonist in the treatment of rheumatoid arthritis

BACKGROUND

Interleukin-1 (IL-1) plays an important role in the pathophysiology and progression of rheumatoid arthritis (RA) by contributing to destruction of cartilage, bone, and periarticular tissues. Inhibiting IL-1 synthesis or activity with the use of recombinant human IL-1 receptor antagonist (anakinra) may prove to be an effective approach to the treatment of RA.

OBJECTIVE

The purpose of this article is to review the effects of anakinra in the treatment of RA.

METHODS

A MEDLINE search from 1982 to 2003 was used to identify animal studies and randomized clinical trials of anakinra and other therapies that target IL-1.

RESULTS

Clinical trials of anakinra have shown that it reduces the signs and symptoms of active disease and slows the rate of radiographic destruction in adults with RA. With anakinra 150 mg/d, 43% of patients achieved an American College of Rheumatology (ACR) 20% response, compared with 27% with placebo (P = 0.014). The ACR20 score indicates at least 20% improvement in the ACR composite score, which includes assessment of tender and swollen joint count, and other clinical end points such as pain and disability assessment. Patients treated with anakinra also experienced a 59% reduction in new bony erosion compared with controls (P < 0.001) and a 65% reduction in joint space narrowing as measured by the modified Sharp score (P = 0.020). Injection-site reactions were the most commonly reported adverse event, occurring in 50%, 73%, and 81% of patients receiving anakinra 30, 75, and 150 mg/d, respectively, compared with 25% of patients receiving placebo. Few serious adverse events were reported, and they typically occurred in patients receiving the highest daily dosage.

CONCLUSIONS

IL-1 is an important cytokine in promoting the damage associated with RA. Anakinra is mildly to moderately effective and well tolerated in patients with active RA when used as monotherapy or in combination with methotrexate.

Rheumatoid arthritis synovium contains plasmacytoid dendritic cells

We have previously described enrichment of antigen-presenting HLA-DR⁺ nuclear RelB⁺ dendritic cells (DCs) in rheumatoid arthritis (RA) synovium. CD123⁺HLA-DR⁺ plasmacytoid DCs (pDCs) and their precursors have been identified in human peripheral blood (PB), lymphoid tissue, and some inflamed tissues. We hypothesized recruitment of pDCs into the inflamed RA synovial environment and their contribution as antigen-presenting cells (APCs) and inflammatory cells in RA. CD11c⁺ myeloid DCs and CD123⁺ pDCs were compared in normal and RA PB, synovial fluid (SF), and synovial tissue by flow cytometry, immunohistochemistry, and electron microscopy and were sorted for functional studies. Nuclear RelB^-CD123⁺ DCs were located in perivascular regions of RA, in a similar frequency to nuclear RelB⁺CD123^- DCs, but not normal synovial tissue sublining. Apart from higher expression of HLA-DR, the numbers and phenotypes of SF pDCs were similar to those of normal PB pDCs. While the APC function of PB pDCs was less efficient than that of PB myeloid DCs, RA SF pDCs efficiently activated resting allogeneic PB T cells, and high levels of IFN-γ, IL-10, and tumor necrosis factor α were produced in response to incubation of allogeneic T cells with either type of SF DCs. Thus, pDCs are recruited to RA synovial tissue and comprise an APC population distinct from the previously described nuclear RelB⁺ synovial DCs. pDCs may contribute significantly to the local inflammatory environment.

Mucosal delivery of anti-inflammatory IL-1Ra by sporulating recombinant bacteria

BACKGROUND

Mucosal delivery of therapeutic protein drugs or vaccines is actively investigated, in order to improve bioavailability and avoid side effects associated with systemic administration. Orally administered bacteria, engineered to produce anti-inflammatory cytokines (IL-10, IL-1Ra), have shown localised ameliorating effects in inflammatory gastro-intestinal conditions. However, the possible systemic effects of mucosally delivered recombinant bacteria have not been investigated.

RESULTS

B. subtilis was engineered to produce the mature human IL-1 receptor antagonist (IL-1Ra). When recombinant B. subtilis was instilled in the distal colon of rats or rabbits, human IL-1Ra was found both in the intestinal lavage and in the serum of treated animals. The IL-1Ra protein in serum was intact and biologically active. IL-1-induced fever, neutrophilia, hypoglycemia and hypoferremia were inhibited in a dose-dependent fashion by intra-colon administration of IL-1Ra-producing B. subtilis. In the mouse, intra-peritoneal treatment with recombinant B. subtilis could inhibit endotoxin-induced shock and death. Instillation in the rabbit colon of another recombinant B. subtilis strain, which releases bioactive human recombinant IL-1beta upon autolysis, could induce fever and eventually death, similarly to parenteral administration of high doses of IL-1beta.

CONCLUSIONS

A novel system of controlled release of pharmacologically active proteins is described, which exploits bacterial autolysis in a non-permissive environment. Mucosal administration of recombinant B. subtilis causes the release of cytoplasmic recombinant proteins, which can then be found in serum and exert their biological activity in vivo systemically.

The usefulness and the limitations of animal models in identifying targets for therapy in arthritis

Animal models have played a critical role in the history of modern drug development for rheumatoid arthritis (RA). In this chapter I examine the contributions of animal models in arthritis therapy from adjuvant arthritis and COX-1 inhibitors to transgenic mice and biological response modifiers. Advances in knowledge of the mechanisms of connective tissue disease are frequently derived from the study of animal models, and these findings frequently identify therapeutic targets that are subsequently evaluated in animal models. Hence a critical relationship between insights into the pathology of arthritis and the development of novel therapeutic approaches exists around the study of animal models of arthritis. In particular, we examine how the study of collagen-induced arthritis in rodents led to pioneering work in cytokine inhibitors for the successful therapy of RA.

Rheumatoid arthritis: regulation of synovial inflammation

Rheumatoid arthritis (RA) is a systemic, inflammatory autoimmune disorder that presents as a symmetric polyarthritis associated with swelling and pain in multiple joints, often initially occurring in the joints of the hands and feet. Articular inflammation causes activation and proliferation of the synovial lining, expression of inflammatory cytokines, chemokine-mediated recruitment of additional inflammatory cells, as well as B cell activation with autoantibody production. A vicious cycle of altered cytokine and signal transduction pathways and inhibition of programmed cell death contribute to synoviocyte and osteoclast mediated cartilage and bone destruction. A combination of targeted interventions at various stages in the pathogenesis of RA will likely be required to control symptoms in certain patients with this complex and potentially disabling disease. The regulation of rheumatoid synovial inflammation will be reviewed, followed by a brief summary of the therapeutic implications of these advances, including strategies targeting key cytokines, signal transduction molecules, co-stimulatory molecules, B cells, chemokines, and adhesion molecules.

In vivo mucosal delivery of bioactive human interleukin 1 receptor antagonist produced by Streptococcus gordonii

BACKGROUND

Interleukin-1 (IL-1) is a cytokine involved in the initiation and amplification of the defence response in infectious and inflammatory diseases. IL-1 receptor antagonist (IL-1ra) is an inactive member of the IL-1 family and represents one of the most potent mechanisms for controlling IL-1-dependent inflammation. IL-1ra has proven effective in the therapy of acute and chronic inflammatory diseases in experimental animal models and also in preliminary clinical trials. However, optimisation of therapeutic schedules is still needed. For instance, the use of drug delivery systems targeting specific mucosal sites may be useful to improve topical bioavailability and avoid side effects associated with systemic administration.

RESULTS

In order to develop systems for the delivery of IL-1ra to mucosal target sites, a Streptococcus gordonii strain secreting human IL-1ra was constructed. The recombinant IL-1ra produced by S. gordonii was composed of the four amino acid residues RVFP of the fusion partner at the N-terminus, followed by the mature human IL-1ra protein. RFVP/IL-1ra displayed full biological activity in vitro in assays of inhibition of IL-1beta-induced lymphocyte proliferation and was released by recombinant S. gordonii in vivo both at the vaginal and the gastrointestinal mucosa of mice. RFVP/IL-1ra appeared beneficial in the model of ulcerative colitis represented by IL-2-/- mice (knock-out for the interleukin-2 gene), as shown by the body weight increase of IL-2-/- mice locally treated with S. gordonii producing RFVP/IL-1ra.

CONCLUSIONS

These results indicate that recombinant S. gordonii can be successfully used as a delivery system for the selective targeting of mucosal surfaces with therapeutic proteins.

Upcoming biologic agents for the treatment of rheumatic diseases

The development of biologic agents has provided rheumatologists with a variety of new and effective treatment options. The success of early biologics, especially etanercept and infliximab for the treatment of rheumatoid arthritis, has spurred research into novel targets for the management of systemic inflammatory and autoimmune diseases. In addition, existing biologics approved for use in other diseases, such as rituximab, are now under study for the treatment of new indications. This article reviews ongoing research on the treatment of rheumatic diseases with new and existing biologic agents.

Tumor necrosis factor alpha-mediated joint destruction is inhibited by targeting osteoclasts with osteoprotegerin

OBJECTIVE

To study the effects of osteoclast-targeted therapies, such as osteoprotegerin (OPG) and pamidronate, on joint inflammation and bone destruction using a tumor necrosis factor alpha (TNF alpha)-transgenic mouse model.

METHODS

Mice were placed into 5 groups that received either OPG, pamidronate, a combination of both agents, infliximab as a positive control, or phosphate buffered saline as a negative control. Treatment was initiated at the onset of arthritis, continued over 6 weeks, and thereafter, the clinical, radiologic, and histologic outcomes were assessed.

RESULTS

A significant improvement in clinical symptoms, as assessed by the reduction of paw swelling, was only found in the infliximab group, whereas all other treatment groups failed to show significant improvement. However, when assessing structural damage with radiographic analysis, a significant retardation of joint damage was evident in animals treated with OPG (55% reduction of erosions), pamidronate (50% reduction of erosions) the combination therapy of OPG and pamidronate (64% reduction of erosions), and with infliximab (66% reduction of erosions). Confirming these data, quantitative histologic analysis revealed a significant reduction in the size of bone erosions in all treatment groups (OPG 56%, pamidronate 53%, OPG and pamidronate 81%, and infliximab 46%) compared with the control group. Furthermore, a significant reduction of osteoclast numbers was seen in animals treated with OPG alone or in combination with pamidronate as well as in animals treated with infliximab.

CONCLUSION

These data suggest that OPG alone or in combination with bisphosphonates is an effective therapeutic tool for the prevention of TNF alpha-mediated destruction of bone by reducing the number of bone-resorbing cells in the inflammatory tissue.

Influence of interleukin-1 receptor antagonist gene polymorphism on disease

Interleukin-1 receptor antagonist (IL-1RA) is a naturally occurring competitive inhibitor of interleukin-1 (IL-1)-induced proinflammatory activity. The IL-1RA gene is polymorphic, resulting in quantitative differences in both IL-1RA and IL-1beta production. Persons homozygous for allele 2 of the IL-1RA gene (IL1RN*2) have a more prolonged and more severe proinflammatory immune response than persons with other IL-1RA genotypes. Thus, being IL1RN*2 homozygous might be beneficial when combating infectious agents or malignantly transformed cells, but it might be detrimental for those with chronic inflammatory conditions or who are pregnant. The IL1RN*2 phenotype is associated with ulcerative colitis and Crohn's disease, lupus erythematosus, vulvar vestibulitis, and possibly with osteoporosis and coronary artery disease. IL1RN*2 homozygosity may also be associated with recurrent spontaneous abortion, preterm birth, and severity of preeclampsia. Conversely, there are negative associations between IL1RN*2 homozygosity and vaginal colonization with mycoplasmas, infection with human cytomegalovirus and Epstein-Barr virus, human immunodeficiency virus proliferation, and the occurrence of ovarian cancer.

Association of clinical, radiological and synovial immunopathological responses to anti-rheumatic treatment in rheumatoid arthritis

OBJECTIVES

To compare immunohistochemical scoring with clinical scoring and radiology for the assessment of rheumatoid arthritis (RA) disease activity, synovial tissue (ST) biopsied arthroscopically was assessed from 18 patients before and after commencement of disease-modifying anti-rheumatic drug (DMARD) therapy.

METHODS

Lymphocytes, macrophages, differentiated dendritic cells (DC), vascularity, tumour necrosis factor (TNF) alpha and interleukin-1beta levels were scored. Clinical status was scored using the American College of Rheumatology (ACR) core set and serial radiographs were scored using the Larsen and Sharp methods. Histopathological evidence of activity included infiltration by lymphocytes, DC, macrophages, tissue vascularity, and expression of lining and sublining TNFalpha. These indices co-varied across the set of ST biopsies and were combined as a synovial activity score for each biopsy.

RESULTS

The change in synovial activity with treatment correlated with the ACR clinical response and with decreased radiological progression by the Larsen score. The ACR response to DMARD therapy, the change in synovial activity score and the slowing of radiological progression were each greatest in patients with high initial synovial vascularity.

CONCLUSIONS

The data demonstrate an association between clinical, radiological and synovial immunopathological responses to anti-rheumatic treatment in RA. High ST vascularity may predict favourable clinical and radiological responses to treatment.

The cathepsin B inhibitor z-FA.fmk inhibits cytokine production in macrophages stimulated by lipopolysaccharide

Cathepsin B has previously been shown to proteolytically activate the proinflammatory caspase-11 in vitro. Here we show that cathepsin B is not involved in activation of caspase-11 induced by lipopolysaccharide (LPS) and subsequent maturation of interleukin (IL)-1beta in macrophages. Nevertheless, we found that the cathepsin B inhibitor benzyloxycarbonyl-Phe-Ala-fluoromethylketone (z-FA.fmk) prevents LPS-induced production of IL-1alpha, IL-1beta, and tumor necrosis factor at the transcriptional level. The latter was not because of cathepsin B inhibition, but was mediated by inhibition of the transactivation potential of the nuclear factor kappaB (NF-kappaB). z-FA.fmk did not prevent LPS-induced activation of p38 mitogen-activated protein kinase, which was shown to be involved in NF-kappaB transactivation in response to LPS. These results suggest that the previously described therapeutic effect of z-FA.fmk in the treatment of rheumatoid arthritis might not only result from inhibition of cathepsin B but also implicates an important contribution from the inhibition of NF-kappaB-dependent gene expression.

Have the new drugs relieved the burden of the orthopedic surgeon?

Rheumatoid arthritis (RA) represents a chronic joint inflammation that leads to destructive lesions of joint cartilage and periarticular bone. Increased understanding of the molecular and cellular mechanisms of RA and recent advantages in molecular technology have resulted in new antirheumatic drugs such as tumor necrosis factor-alpha blockers, inhibitors of interleukin-1, and novel disease-modifying antirheumatic drugs such as leflunomide. This review summarizes the important effects of the novel antirheumatic drugs and their potential impact on the work of orthopedic surgeons. The ability of these agents not only to improve the clinical signs and symptoms of RA but also to prevent progressive joint damage promises support to the work of orthopedic surgeons and to the interdisciplinary treatment of RA patients. The challenge, however, will be to conduct studies that show the concrete way in which the single drugs may best relieve the burden of the orthopedic surgeon.

Pathogenesis of rheumatoid arthritis. The role of T cells and other beasts

The evidence coming from the different experimental approaches reviewed in this article strongly supports the hypothesis that RA is T-cell driven at all stages of the disease. Although the effector phases responsible for the events that lead to joint destruction involve several different cell types, cytokines, and other mediators, T cells still direct operations behind the scenes. Direct experimental proof of this proposition in patients is still lacking, but the development of nondepleting modulating CD4 monoclonal antibodies may provide new tools to test this hypothesis. In this respect, it is encouraging that using one such reagent, we have recently shown that not only did the activity of the disease improve but, more importantly, the inflammatory indices and production of non-T-cell cytokines were reduced. This is not to dissimilar from the results of experiments described in animals, where by blocking synovial T cells, the production of IL-1 beta and TNF alpha could be decreased by more than 90%. From this perspective, it may be predicted that by modulating T cells in the joint, it is possible to achieve our ultimate goal of permanently switching off the disease.

Update on synovitis

Rheumatoid arthritis (RA) is an inflammatory disorder associated with chronic synovitis, eventually leading to cartilage and bone destruction in the joints. Synovitis is associated with the activation of various cells in the synovium including synovial lining cells, interstitial macrophages, endothelial cells, lymphocytes, and fibroblasts. The key mechanisms underlying synovitis include inflammatory cell adhesion and activation, the production of mediators (such as cytokines, chemokines, and growth factors), angiogenesis, joint destruction, fibrosis, and bone resorption. These important events, as well as the role of inflammatory cells, cell surface molecules, and soluble mediators are updated and discussed in this review. Some aspects and strategies of current or future immunotherapy are also discussed because these animal and human trials provide information on the pathogenesis of inflammatory synovitis.

Molecular and cellular mediators of interleukin-1-dependent acute inflammatory arthritis

OBJECTIVE

To examine the molecular and cellular mechanisms in a model of acute inflammatory monarticular arthritis induced by methylated bovine serum albumin (mBSA) and interleukin-1 (IL-1).

METHODS

Mice were injected intraarticularly with mBSA on day 0 and subcutaneously with recombinant human IL-1beta on days 0-2. At day 7, knee joints were removed and assessed histologically. Flow cytometry and RNase protection were used to analyze IL-1-dependent events.

RESULTS

C57BL/6 (B6), 129/Sv, and (B6 x 129/ Sv)F1 hybrid mice, all H-2b strains, were susceptible to mBSA/IL-1-induced arthritis, whereas C3H/HeJ (H-2k) mice were not. B6 mice lacking T and B cells (RAG1-/-) or major histocompatibility complex (MHC) class II antigens (MHCII-/-), and B6 mice treated with a CD4+ T cell-depleting monoclonal antibody, were resistant to disease. In contrast, B cell-deficient (muMT/ muMT) mice developed arthritis at an incidence and severity similar to that of controls. RelB-deficient (RelB-/-) bone marrow chimeric mice had arthritis that was significantly reduced in incidence and severity. In B6 mice, flow cytometry demonstrated an IL-1-dependent leukocyte infiltration into the synovial compartment and RNase protection assays revealed induction of messenger RNA (mRNA) for the chemokines monocyte chemoattractant protein 1, macrophage inhibitory protein 2 (MIP-2), RANTES, MIP-1alpha, and MIP-1beta, in vivo and in vitro.

CONCLUSION

Arthritis induced by mBSA/IL-1 is strain specific and dependent on CD4+ T lymphocytes and at least partially on RelB, but not on B lymphocytes or antibody. IL-1 contributes to leukocyte recruitment to the synovium and directly induces chemokine mRNA production by synovial cells. This model of acute monarticular arthritis is particularly suitable for further investigations into cell-mediated immunity in arthritis and the role of IL-1.

Early response genes induced in chondrocytes stimulated with the inflammatory cytokine interleukin-1beta

Recent work has established that IL-1beta plays a central role in the inflammation and connective tissue destruction observed in both rheumatoid arthritis and osteoarthritis. These processes result from the ability of this inflammatory cytokine to activate expression of genes for neutral proteases, such as the matrix metalloproteinases. While IL-1beta activates matrix metalloproteinase genes within several hours, it also activates immediate early genes, which are required for the later expression of matrix metalloproteinases and other arthritis-perpetuating genes, are also activated. To identify putative immediate early genes involved in IL-1beta-mediated arthritic disease, a chondrocytic cell line (SW1353) was stimulated with this cytokine for 2 hours, total RNA was isolated, and expressed genes were identified by microarray analysis. This analysis identified alterations in the expression of multiple transcription factors, cytokines, growth factors and their receptors, adhesion molecules, proteases, and signaling intermediates that may contribute to inflammation and cartilage destruction in arthritis. Interestingly, confirmation of the expression of activating protein-1 family members by reverse transcriptase polymerase chain reaction revealed a preferential increase in junB, a known transcriptional antagonist of c-jun. The failure to observe induction of early growth response gene-1, which was detected by reverse transcriptase polymerase chain reaction to be substantially and transiently induced by 1 hour of IL-1 treatment, may be explained by the known instability of the message after early induction. However, this analysis has identified numerous IL-1beta-responsive genes that warrant further investigation as mediators of disease in arthritis.

Modulation of fibroblast-mediated cartilage degradation by articular chondrocytes in rheumatoid arthritis

OBJECTIVE

To determine the role of chondrocytes and factors released from chondrocytes in cartilage destruction by fibroblast-like synoviocytes (FLS) derived from patients with rheumatoid arthritis (RA).

METHODS

RA FLS from 2 patients were implanted into SCID mice, together with fresh articular cartilage or with cartilage that had been stored for 24 hours at 4 degrees C or at 37 degrees C. The invasion of the same RA FLS into the fresh and stored cartilage was compared histologically using a semiquantitative scoring system. In addition, we investigated whether protein synthesis in chondrocytes affects the invasion of RA FLS in vitro. A 3-dimensional cartilage-like matrix formed by cultured chondrocytes was labeled with 35S. After formation of the cartilage-like matrix, protein synthesis was blocked with cycloheximide. The invasion of RA FLS from 6 patients into cycloheximide-treated and untreated matrix was assessed by measuring the released radioactivity in coculture with and without interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha).

RESULTS

The SCID mouse experiments showed a significant invasion of RA FLS into the cartilage (overall mean score 3.2) but revealed significant differences when the invasion of the same RA FLS into fresh and stored cartilage was compared. RA FLS that were implanted with fresh articular cartilage showed a significantly higher invasiveness than those implanted with pieces of cartilage that had been stored for 24 hours (overall mean score 2.3). Storage at 37 degrees C and 4 degrees C resulted in the same reduction of invasion (35% and 37%, respectively). In the in vitro experiments, RA FLS rapidly destroyed the cartilage-like matrix. Blocking of chondrocyte protein biosynthesis significantly decreased the invasion of RA FLS, as shown by a decreased release of radioactivity. Addition of IL-1beta, but not TNFalpha, to the cocultures partially restored the invasiveness of RA FLS.

CONCLUSION

These data underline the value of the SCID mouse in vivo model of rheumatoid cartilage destruction and demonstrate that chondrocytes contribute significantly to the degradation of cartilage by releasing factors that stimulate RA FLS. Among those, IL-1beta-mediated mechanisms might be of particular importance.

Anti-cytokine therapy for rheumatoid arthritis

Tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) are important in mediating inflammation in rheumatoid arthritis (RA). Randomized phase II and III clinical trials of anti-TNF reagents (infliximab and etanercept) have demonstrated an acceptable safety profile and marked clinical efficacy in cases of RA that have not responded adequately to conventional therapy. Combination therapy with methotrexate (MTX) appears to be particularly effective in patients whose disease activity persists despite prior disease-modifying antirheumatic drugs (DMARDs) and ongoing MTX monotherapy. DMARD-recalcitrant disease may become the main indication for the use of anti-TNF drugs in patients with RA. Trials of IL-1 receptor antagonist show a relatively modest anti-inflammatory effect and a possible retardation of joint damage. Whether anti-TNF therapy protects joints from structural damage is under investigation. One anti-TNF reagent has already been approved in the United States for the treatment of RA, and other cytokine antagonists or agonists are under development.

Distribution of (76)Br-labeled antisense oligonucleotides of different length determined ex vivo in rats

Oligonucleotides may hybridize with high selectivity to an RNA sequence and can be used for the monitoring of gene expression or for its inhibition in experimental or therapeutic purposes. As part of the development of positron emission tomography (PET) methods, different lengths (30, 20, 12 and 6 mer) of antisense phosphorothioate oligonucleotides complementary to rat chromogranin A were labeled with [(76)Br] using a prosthetic group. The (76)Br-oligonucleotides were injected into rat's tail vein (1-2 MBq/rat), and the radioactivity distribution was analyzed after 20 h using whole body autoradiography or by measurement of organ radioactivity concentration. The whole body autoradiography showed different distribution depending on the oligonucleotide length. The organs with highest uptake changed from kidney cortex (with 6 or 12 mer), kidney cortex and liver (with 20 mer), to liver and spleen (with 30 mer). With 20 or 30 mer sequences, uptake could be observed in the adrenals. Kidneys and livers from rats receiving 20 mer or 30 mer (76)Br-oligonucleotides were analyzed with respect to subcellular distribution and DNA/RNA/protein fraction. 30%-45% of the radioactivity was found in the nuclear fraction. More than 80% of the radioactivity was recovered in the high molecular weight fraction (as proteins or oligonucleotides longer than 10 mer) using size exclusion (NAP 5) gelfiltration or cetylpyridinium bromide (CPB) precipitation. This work indicates the potential to perform kinetic whole body studies of (76)Br-oligonucleotides using PET.

Dendritic cells: the driving force behind autoimmunity in rheumatoid arthritis?

Dendritic cells (DC) are likely to play a significant role in immune-mediated diseases such as autoimmunity and allergy. To date there are few treatments capable of inducing permanent remission in rheumatoid arthritis (RA) and elucidation of the role of DC may provide specific strategies for disease intervention. Dendritic cells have proven to be powerful tools for immunotherapy and investigations are under way to determine their clinical efficacy in transplantation and viral and tumour immunotherapy. The present review will focus on the current view of DC and their role in autoimmunity, in particular RA. Two possible roles for DC in the pathogenesis of RA will be proposed, based on recent advances in the field.