Immunological therapies for rheumatoid arthritis

Macrophage-Mimicking Cellular Nanoparticles Scavenge Proinflammatory Cytokines in Specimens of Patients with Inflammatory Disorders

Effectively neutralizing inflammatory cytokines is crucial for managing a variety of inflammatory disorders. Current techniques that target only a subset of cytokines often fall short due to the intricate nature of redundant and compensatory cytokine networks. A promising solution to this challenge is using cell membrane-coated nanoparticles (CNPs). These nanoparticles replicate the complex interactions between cells and cytokines observed in disease pathology, providing a potential avenue for multiplex cytokine scavenging. While the development of CNPs using experimental animal models has shown great promise, their effectiveness in scavenging multiple cytokines in human diseases has yet to be demonstrated. To bridge this gap, this study selected macrophage membrane-coated CNPs (MФ-CNPs) and assessed their ability to scavenge inflammatory cytokines in serum samples from patients with COVID-19, sepsis, acute pancreatitis, or type-1 diabetes, along with synovial fluid samples from patients with rheumatoid arthritis. The results show that MФ-CNPs effectively scavenge critical inflammatory cytokines, including interleukin (IL)-6, IL-8, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, in a dose-dependent manner. Overall, this study demonstrates MФ-CNPs as a multiplex cytokine scavenging formulation with promising applications in clinical settings to treat a range of inflammatory disorders.

Eichhornia crassipes Ameliorated Rheumatoid Arthritis by Modulating Inflammatory Cytokines and Metalloproteinase Enzymes in a Rat Model

Background and Objectives: This study was planned to investigate the anti-arthritic property of flowers of E. crassipes in a Sprague-Dawley rat model by administering Freund's Complete Adjuvant (FCA). Materials and Methods: Arthritis was induced at day 0 in all rats except negative controls, while arthritic progress and paw edema were analyzed on specific days (8th, 13th, 18th, and 23rd) via the macroscopic arthritic scale and a digital Vernier caliper, respectively. Histopathological parameters were examined using a Hematoxylin and Eosin (H&E) staining method. Blood samples were withdrawn from rats to investigate the effects of the E. crassipes flower on the mRNA expression values of inflammatory markers, via a reverse transcription PCR technique. Serum samples were used to determine prostaglandin E2 (PGE2) levels using enzyme-linked immunosorbent assay (ELISA). Values of alanine transaminase (ALT), aspartate aminotransferase (AST), creatinine, and urea, besides hematological parameters, i.e., the hemoglobin (Hb) content and complete blood count (CBC), were investigated. Results: The data showed that E. crassipes inhibited the arthritic progress and ameliorated the paw edema. The amelioration of parameters assessed via the histopathological analysis of ankle joints, as well as via hematological analysis, confirmed the diminution of rheumatoid arthritis (RA) in the plant-treated groups. Treatment with E. crassipes inhibited the expression levels of tumor necrosis factor-α (TNF-α), interleukins (IL-1β and IL-6), nuclear factor KappaB (NF-κB), matrix metalloproteinase (MMP-2 and MMP-3), and vascular endothelial growth factor (VEGF). Serum PGE2 levels were also found to be reduced in treatment groups. A biochemical investigation revealed the improvements in hepatic markers in plant-treated groups. The data indicated that the plant has no hepatotoxic or nephrotoxic effects at the studied dose. GC-MS (Gas Chromatography-Mass Spectrometry) analysis displayed the presence of phytochemicals having known anti-inflammatory and antioxidant properties. Conclusions: Therefore, it may be concluded that E. crassipes possesses anti-arthritic characteristics that could be attributed to the modulation of pro-inflammatory cytokines, MMPs, and PGE2 levels.

Neuroimmune semaphorins as costimulatory molecules and beyond

Several neuronal guidance proteins, known as semaphorin molecules, function in the immune system. This dual tissue performance has led to them being defined as "neuroimmune semaphorins". They have been shown to regulate T cell activation by serving as costimulatory molecules. Similar to classical costimulatory molecules, neuroimmune semaphorins are either constitutively or inducibly expressed on immune cells. In contrast to the classical costimulatory molecule function, the action of neuroimmune semaphorins requires the presence of two signals, the first one provided by TCR/MHC engagement, and the second one provided by B7/CD28 interaction. Thus, neuroimmune semaphorins serve as a "signal three" for immune cell activation and regulate the overall intensity of immune response. The current knowledge on their structures, multiple receptors, specific cell/tissue/organ expression, and distinct functions in different diseases are summarized and discussed in this review.

Rheumatoid arthritis fibroblast-like synoviocytes co-cultured with PBMC increased peripheral CD4+ CXCR5+ ICOS+ T cell numbers

'Circulating' T follicular helper cells (Tfh), characterized by their surface phenotypes CD4⁺ chemokine receptor 5 (CXCR5)⁺ inducible co-stimulatory molecule (ICOS)⁺ , have been identified as the CD4⁺ T cell subset specialized in supporting the activation, expansion and differentiation of B cells. Fibroblast-like synoviocytes (FLS) are critical in promoting inflammation and cartilage destruction in rheumatoid arthritis (RA), and the interaction between FLS and T cells is considered to facilitate FLS activation and T cell recruitment. However, it remains unknown whether RA-FLS co-cultured with activated peripheral blood mononuclear cells (PBMC) has immunoregulatory effects on peripheral Tfh. In the present study, we co-cultured RA-FLS with or without anti-CD3/CD28-stimulated PBMC. The results showed that RA-FLS co-cultured with stimulated PBMC could increase the numbers of CD4⁺ CXCR5⁺ ICOS⁺ T cells of RA PBMC possibly via the production of interleukin (IL)-6, a critical cytokine involved in the differentiation of Tfh cells. We also observed increased reactive oxygen species (ROS) levels in the co-culture system of RA-FLS and PBMC. The percentage of CD4⁺ CXCR5⁺ ICOS⁺ T cells was decreased when ROS production was inhibited by N-acetyl-L-cysteine (NAC), a specific inhibitor which can decrease ROS production. In addition, we showed that the higher levels of tumour necrosis factor (TNF)-α and IL-1β in the co-culture system and the blocking of TNF receptor 2 (TNF-R2) and IL-1β receptor (IL-1βR) both decreased the numbers of CD4⁺ CXCR5⁺ ICOS⁺ T cells. Our study reveals a novel mechanistic insight into how the interaction of RA-FLS and PBMC participates in the RA pathogenesis, and also provides support for the biologicals application for RA.

Astilbin from Smilax glabra Roxb. Attenuates Inflammatory Responses in Complete Freund's Adjuvant-Induced Arthritis Rats

Astilbin, a flavonoid compound, was isolated from the rhizome of Smilax glabra Roxb. (with red cross-section) grown in Guizhou Province, China. We accessed its effect and potential mechanism on attenuation of the inflammatory response in CFA-induced AA rats. Our results showed that daily oral administration of astilbin at 5.3 mg/kg reduced joint damage in the hind paw of AA rats. Accordingly, astilbin exhibited remarkable inhibitory effects on TNF-α, IL-1β, and IL-6 mRNA expression. Significant decrease of serum cytokine levels of TNF-α, IL-1β, and IL-6 was also observed in astilbin-treated AA rats compared to the vehicle-treated AA rats. The reduced expression of these cytokines was associated with protein activity suppression of three key molecular targets in the pathogenesis of RA, including IKKβ, NF-κB p65 subunit, and TLR adaptor MyD88. Furthermore, the therapeutic effects of astilbin on the inhibition of cytokines production as well as the reduction of inflammatory response in AA rats are close to a commonly used antirheumatic drug, leflunomide. Collectively, our data suggest that the action mechanism of astilbin, as an anti-inflammatory agent for RA treatment, is associated with modulating the production of proinflammatory cytokines and inhibiting the expression of key elements in NF-κB signaling pathway mediated by TLR.

Innate lymphoid cells in autoimmunity: emerging regulators in rheumatic diseases

Innate lymphoid cells (ILCs) are important in the regulation of barrier homeostasis. These cells do not express T cell receptors but share many functional similarities with T helper cells and cytotoxic CD8⁺ T lymphocytes. ILCs are divided into three groups, namely group 1 ILCs, group 2 ILCs and group 3 ILCs, based on the transcription factors they depend on for their development and function, and the cytokines they produce. Emerging data indicate that ILCs not only have protective functions but can also have detrimental effects when dysregulated, leading to chronic inflammation and autoimmune diseases, including asthma, inflammatory bowel disease, graft-versus-host disease, psoriasis, rheumatoid arthritis and atopic dermatitis. Elucidation of the cytokine pathways involved in various autoimmune diseases - and the identification of ILCs as potent producers of these cytokines - points towards a potential role for these cellular players in the pathophysiology of these diseases. In this Review we discuss the current knowledge of the role of ILCs in the pathogenesis of rheumatic and other autoimmune diseases.

Semaphorin 4A as novel regulator and promising therapeutic target in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease manifesting in joint destruction. The recognized hallmark of RA pathogenesis is the involvement of immune cells which produce many mediators potentiating an inflammatory environment. RA synovial fibroblasts (RASFs) contribute significantly to disease progression by initiating and regulating many pathways of joint destruction. Detailed molecular insights into RASF biology may lead to identification of important therapeutic targets. The discovery of common molecular targets for joint resident and inflammatory cells may help to develop the most effective therapeutic strategy. One such pathway includes semaphorin 4A as reported in a recent article in Arthritis Research & Therapy.

Macrophage repolarization with targeted alginate nanoparticles containing IL-10 plasmid DNA for the treatment of experimental arthritis

In this study, we have shown for the first time the effectiveness of a non-viral gene transfection strategy to re-polarize macrophages from M1 to M2 functional sub-type for the treatment of rheumatoid arthritis (RA). An anti-inflammatory (IL-10) cytokine encoding plasmid DNA was successfully encapsulated into non-condensing alginate based nanoparticles and the surface of the nano-carriers was modified with tuftsin peptide to achieve active macrophage targeting. Enhanced localization of tuftsin-modified alginate nanoparticles was observed in the inflamed paws of arthritic rats upon intraperitoneal administration. Importantly, targeted nanoparticle treatment was successful in reprogramming macrophage phenotype balance as ∼66% of total synovial macrophages from arthritic rats treated with the IL-10 plasmid DNA loaded tuftsin/alginate nanoparticles were in the M2 state compared to ∼9% of macrophages in the M2 state from untreated arthritic rats. Treatment significantly reduced systemic and joint tissue pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) expression and prevented the progression of inflammation and joint damage as revealed by magnetic resonance imaging and histology. Treatment enabled animals to retain their mobility throughout the course of study, whereas untreated animals suffered from impaired mobility. Overall, this study demonstrates that targeted alginate nanoparticles loaded with IL-10 plasmid DNA can efficiently re-polarize macrophages from an M1 to an M2 state, offering a novel treatment paradigm for treatment of chronic inflammatory diseases.

Regulation of TNF-α with a focus on rheumatoid arthritis

Cytokines and chemokines represent two important groups of proteins that control the human immune system. Dysregulation of the network in which these immunomodulators function can result in uncontrolled inflammation, leading to various diseases including rheumatoid arthritis (RA), characterized by chronic inflammation and bone erosion. Potential triggers of RA include autoantibodies, cytokines and chemokines. The tight regulation of cytokine and chemokine production, and biological activity is important. Tumor necrosis factor-α (TNF-α) is abundantly present in RA patients' serum and the arthritic synovium. This review, therefore, discusses first the role and regulation of the major proinflammatory cytokine TNF-α, in particular the regulation of TNF-α production, post-translational processing and signaling of TNF-α and its receptors. Owing to the important role of TNF-α in RA, the TNF-α-producing cells and the dynamics of its expression, the direct and indirect action of this cytokine and possible biological therapy for RA are described.

Bosentan, an endothelin receptor antagonist, ameliorates collagen-induced arthritis: the role of TNF-α in the induction of endothelin system genes

OBJECTIVE

Endothelins (ETs) are involved in several inflammatory events. The present study investigated the efficacy of bosentan, a dual ETA/ETB receptor antagonist, in collagen-induced arthritis (CIA) in mice.

TREATMENT

CIA was induced in DBA/1J mice. Arthritic mice were treated with bosentan (100 mg/kg) once a day, starting from the day when arthritis was clinically detectable.

METHODS

CIA progression was assessed by measurements of visual clinical score, paw swelling and hypernociception. Histological changes, neutrophil infiltration and pro-inflammatory cytokines were evaluated in the joints. Gene expression in the lymph nodes of arthritic mice was evaluated by microarray technology. PreproET-1 mRNA expression in the lymph nodes of mice and in peripheral blood mononuclear cells (PBMCs) was evaluated by real-time PCR. The differences were evaluated by one-way ANOVA or Student's t test.

RESULTS

Oral treatment with bosentan markedly ameliorated the clinical aspects of CIA (visual clinical score, paw swelling and hyperalgesia). Bosentan treatment also reduced joint damage, leukocyte infiltration and pro-inflammatory cytokine levels (IL-1β, TNFα and IL-17) in the joint tissues. Changes in gene expression in the lymph nodes of arthritic mice returned to the levels of the control mice after bosentan treatment. PreproET mRNA expression increased in PBMCs from rheumatoid arthritis (RA) patients but returned to basal level in PBMCs from patients under anti-TNF therapy. In-vitro treatment of PBMCs with TNFα upregulated ET system genes.

CONCLUSION

These findings indicate that ET receptor antagonists, such as bosentan, might be useful in controlling RA. Moreover, it seems that ET mediation of arthritis is triggered by TNFα.

Interactive cytokine regulation of synoviocyte lubricant secretion

Cytokine regulation of synovial fluid (SF) lubricants, hyaluronan (HA), and proteoglycan 4 (PRG4) is important in health, injury, and disease of synovial joints, and may also provide powerful regulation of lubricant secretion in bioreactors for articulating tissues. This study assessed lubricant secretion rates by human synoviocytes and the molecular weight (MW) of secreted lubricants in response to interleukin (IL)-1beta, IL-17, IL-32, transforming growth factor-beta 1 (TGF-beta1), and tumor necrosis factor-alpha (TNF-alpha), applied individually and in all combinations. Lubricant secretion rates were assessed using ELISA and binding assays, and lubricant MW was assessed using gel electrophoresis and Western blotting. HA secretion rates were increased approximately 40-fold by IL-1beta, and increased synergistically to approximately 80-fold by the combination of IL-1beta + TGF-beta1 or TNF-alpha + IL-17. PRG4 secretion rates were increased approximately 80-fold by TGF-beta1, and this effect was counterbalanced by IL-1beta and TNF-alpha. HA MW was predominantly <1 MDa for controls and individual cytokine stimulation, but was concentrated at >3 MDa after stimulation by IL-1beta + TGF-beta1 + TNF-alpha to resemble the distribution in human SF. PRG4 MW was unaffected by cytokines and similar to that in human SF. These results contribute to an understanding of the relationship between SF cytokine and lubricant content in health, injury, and disease, and provide approaches for using cytokines to modulate lubricant secretion rates and MW to help achieve desired lubricant composition of fluid in bioreactors.

Manipulating B cell homeostasis: a key component in the advancement of targeted strategies

Understanding the homeostatic mechanisms governing lymphocyte pools achieves critical importance as lymphocyte-targeted therapies expand in use and scope. The primacy of B lymphocyte stimulator (BLyS) family ligands and receptors in governing B lymphocyte homeostasis has become increasingly clear in recent years, affording insight into novel opportunities and potential pitfalls for targeted B cell therapeutics. Interclonal competition for BLyS-BR3 interactions determines the size of naïve B cell pools and can regulate the stringency of selection applied as cells complete maturation. Thus one of the predicted consequences of ablative therapies targeting primary pools is relaxed negative selection. This suggests that BLyS levels and B cell reconstitution rates may serve useful prognostic roles and that BLyS itself might be targeted to circumvent relapse. Alternatively, manipulations that allow rare, minimally autoreactive specificities to survive and mature may lead to opportunities in cases where antibody-based vaccine development has heretofore been unsuccessful. BLyS family ligands and receptors also play a role in activated and memory B cell pools, suggesting they might likewise be targeted to promote or delete particular antigen-experienced subpopulations in a similar way.

Vaccination with cytokines in autoimmune diseases

Most autoimmune diseases have an unknown etiology, but all involve cytokines cascade in their development. At the present time, several cytokines have been identified as major targets in various autoimmune diseases, involving the development of monoclonal antibodies (MAbs) against those cytokines. Even if MAbs are indeed efficient, the passive immunotherapies also present some disadvantages and are expensive. To counter this, several strategies have been developed, including active immunotherapy, based on the vaccination principle. The aim of such a strategy is to induce a B cell response and to obtain autoantibodies able to neutralize the interaction of the self-cytokine with its receptor. To that purpose, cytokines (entire or peptide) are either coupled with a protein-carrier or virus-like particle, or modified with foreign Th cell epitopes. DNA vaccination can also be used with cytokine sequences. This review focuses on the different vaccination strategies with cytokines (including Tumor Necrosis Factor (TNF)alpha, Interleukin-1beta (IL-1beta), IL-17) in different autoimmune diseases in preclinical studies; the benefit/risk ratio of such a strategy and the present development of clinical trials in some autoimmune diseases are also discussed.

7th EFIS Tatra Immunology Conference. Molecular determinants of T-cell immunity. 24-28 June 2006, High Tatra Mountains, Slovakia

This meeting was hosted by the European Federation of Immunological Societies celebrating its 7th meeting in the High Tatra Mountains of Slovakia on 24-28 June 2006. Entitled molecular determinants of T-cell immunity, the meeting covered a wide range of novel methods to regulate an unwanted immune response in autoimmunity and boost the immune system to combat viral infection and cancer.