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Medical Specialties / Rheumatology / Rheumatoid Arthritis

Wnt Signaling in Dendritic Cells: Its Role in Regulation of Immunity and Tolerance

Abstract: A fundamental puzzle in immunology is how the immune system launches robust immunity against pathogens while maintaining a state of tolerance to the body's own tissues and the trillions of commensal microorganisms and food antigens that confront them every day. Innate immune cells, such as dendritic cells (DCs) and macrophages, play a fundamental role in this process. Emerging studies have highlighted that the Wnt signaling pathway, particularly in DCs, plays a major role in regulating tolerance versus immunity. Here, we review our current understanding of how Wnt-signaling shapes the immune response and, in addition, highlight unanswered questions, the solution of which will be imperative in the rational exploitation of this pathway in vaccine design and immune therapy. ... Read more

T Cell Chemokine Receptor Patterns as Pathogenic Signatures in Autoimmunity

Abstract: Autoimmune diseases arise from aberrant activation of immune cells directed against endogenous autoantigens expressed throughout the human body. While the initiating triggers remain poorly understood, the self-perpetuating phase of these diseases is directly linked to the ongoing recruitment of inflammatory cells that traffic to the affected anatomical sites. T lymphocytes are prominent drivers of many autoimmune diseases and the targeted trafficking of these cells to infiltrate the affected organs is often a common denominator. The regulation of T cell trafficking involves the coordinated expression of specific patterns of chemokines and the reciprocal expression of cognate chemokine receptors on T cell membranes. Thereby, chemokines direct the specific trafficking of a wide array of responsive activated immune cells. Specific patterns of chemokine receptor expression can correlate with disease activity in an autoimmune disease, confirming the importance of further characterizing the T cells that infiltrate specific sites of autoimmunity. Herein, we will review our current understanding of the roles of chemokines in two common autoimmune diseases: rheumatoid arthritis and multiple sclerosis. We also discuss the implications for chemokine receptor signatures in autoimmune pathogenesis, and how these may provide novel targets for therapeutic intervention. ... Read more

Determination of Role of Thromboxane A2 in Rheumatoid Arthritis

Abstract: Introduction: To date, the etiology of rheumatoid arthritis (RA) remains largely unknown, and the therapies are still unsatisfactory. The biosynthesis of thromboxane A2 (TxA2) is increased in RA patients, suggesting a role of TxA2 in RA pathology. Methods: RA patients were divided into two groups, DMARDs and non-DMARDs, according to their use of disease-modifying antirheumatic drugs (DMARDs). Sera from RA patients and healthy controls were extracted and subjected to enzyme immunoassays for measurement of the thromboxane B2 (TxB2) level. The statistical correlations between serum TxB2 levels and disease activity score of 28 joints (DAS28), C-reactive protein (CRP), or erythrocyte sedimentation rate (ESR) were calculated. Moreover, the effects of dual TxA2 modulator BM567 on cell proliferation as well as protein expression of α-actinin and NF-κB2 in RA fibroblast-like synovial (FLS) cells MH7A were determined by MTS assays and Western blot analysis, respectively. The effects of BM567 on mRNA expression of cyclooxygenase (COX)-2, a downstream product of NF-κB2 and an upstream enzyme of TxA2, was examined by real-time quantitative PCR experiments. Results: Serum TxB2 level was significantly higher in RA patients as compared to healthy controls. Both DAS28 score and serum TxB2 levels were slightly lower in the DMARDs group than the non-DMARDs group, without statistical significance, and there was positive correlation between these two factors. BM567 significantly suppressed cell proliferation as well as expression of α-actinin, NF-κB2, p52, and COX-2 in MH7A. Conclusion: TxA2 plays an important role in RA pathology, synovial cell proliferation in particular, through an auto-regulatory feedback loop. Thus, targeting TxA2 may represent a promising add-on therapy in the treatment of RA. ... Read more

Advances in the Etiology and Mechanisms of Type 1 Diabetes

Abstract: Type 1 diabetes (T1D) is an insulin-dependent form of diabetes resulting from the autoimmune destruction of pancreatic beta cells. The past few decades have seen tremendous progress in our understanding of the molecular basis of the disease, with the identification of susceptibility genes and autoantigens, the demonstration of several abnormalities affecting various cell types and functions, and the development of improved assays to detect and monitor autoimmunity and beta cell function. New findings about the disease pathology and pathogenesis are emerging from extensive studies of organ donors with T1D promoted by the JDRF nPOD (Network for the Pancreatic Organ Donor with Diabetes). Furthermore, the establishment of extensive collaborative projects including longitudinal follow-up studies in relatives and clinical trials are setting the stage for a greater understanding of the role of environmental factors, the natural history of the disease, and the discovery of novel biomarkers for improved prediction, which will positively impact future clinical trials. Recent studies have highlighted the chronicity of islet autoimmunity and the persistence of some beta cell function for years after diagnosis, which could be exploited to expand therapeutic options and the time window during which a clinical benefit can be achieved. ... Read more

Novel Insight into the Role of Alpha-actinin-1 in Rheumatoid Arthritis

Abstract: The knowledge of rheumatoid arthritis (RA) pathology is rapidly advancing and becoming more and more complex, and a simple fact is that the major organ targeted by RA pathogenic factors is the synovium. It is well known that fibroblast-like synovial (FLS) cell is the major cell-type for constructing synovium. Following stimulation by pro-inflammatory cytokines, FLS cells are phenotypically changed to have the capability to proliferate abnormally. Recently we demonstrated that α-actinin-1 (ACTN1) gene is significantly increased in synovial tissues obtained from RA, as compared to osteoarthritis (OA). We therefore reviewed the literature about α-actinins (ACTNs) and we now propose that ACTN1 may function as a "terminal effector" of intracellular signalings initiated by tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) in RA. Future research on ACTN1 may help to improve the current therapeutic and diagnostic strategies of RA. ... Read more

Pharmacogenomics in Childhood Rheumatic Disorders: A Foundation for Future Individualized Therapy

Abstract: Investigating the effect of genotype on drug response in children is an evolving field, with many challenges, but there is great potential to optimize safe and effective use of drugs in children. An exponential increase in available medications for use in children with rheumatic disease has opened seemingly endless genotype/phenotype relationships to explore, but challenges inherent in studying rare diseases and the often overlooked role of ontogeny contribute to limitations in pharmacogenomic studies in this population. With careful recognition of the importance of development, improved phenotyping with the incorporation of biomarkers, and expanding collaborative efforts on a national and even international scale, the field of pediatric rheumatology has the opportunity to strategically study the new therapeutic armamentarium available and provide individualized safe and effective therapies to our population of patients. ... Read more

Scleritis: Challenges in Immunopathogenesis and Treatment

Abstract: Scleritis is an uncommon disease characterized by inflammation of the sclera and adjacent ocular structures. Recent studies have led to significant progress in understanding the epidemiology, immunopathogenesis, severity assessment, treatment, and prognosis of this potentially sight threatening disease. Despite these advances, significant challenges remain regarding our understanding of the mechanisms of scleral destruction and inflammation, and the rational approach to treatment. Information from studies in associated systemic diseases and vasculitis and a small number of studies of ocular tissue has revealed the prominent role of T and B cells, autoantibodies, immune complexes, and cytokines, such as TNF-alpha. These studies have prompted clinical trials that have demonstrated the effectiveness of anti-TNF, anti-B cell therapy, systemic immunosuppression, and more recently the use of local sub-conjunctival steroid treatment. ... Read more

The Quest for Better Understanding of HLA-Disease Association: Scenes from a Road Less Travelled By

Abstract: Dozens of human diseases and health traits are significantly more common among individuals carrying particular human leukocyte antigens (HLA) alleles. The underlying mechanism of this phenomenon, commonly referred to as "HLA-disease association," has been the subject of a decades-long debate. The prevailing hypotheses implicate an auto-aggressive immune response due to aberrant presentation of self-, self-mimicking-, or altered self-antigens by HLA molecules. However, the identity of such putative antigens remains elusive in the vast majority of HLA-associated diseases. Moreover, antigen presentation-based hypotheses are difficult to reconcile with epidemiologic data and functional characteristics of HLA molecules. To provide better answers to these inconsistencies an alternative theory involving allele-based, antigen presentation-independent mechanism is proposed here. Recent research findings in rheumatoid arthritis, an emblematic HLA-associated disease, lend support to the proposed theory. ... Read more

Novel Therapeutic Approaches for Corneal Disease

Abstract: Congenital and acquired corneal opacities, and diseases of the ocular surface, are blinding conditions that impose physical, psychological, and financial constraints upon the sufferer. In the past, corneal and corneal epithelial stem cell transplantation have been the major treatment for severe corneal and ocular surface disease, respectively, but the sequelae of neovascularization and inflammatory eye disease cause many grafts to undergo irreversible immunological rejection. Furthermore, in the case of corneal dystrophies, the original disease may recur in the graft. New therapeutic options for diseases of the cornea and ocular surface are now being actively explored in experimental animals and in clinical trials. Antibody-based biologics are being tested for their ability to reduce blood and lymphatic vessel ingrowth into the cornea, and to reduce inflammation. Many new biomaterials are being examined for their capacity to transfer drugs and corneal epithelial cell progenitor cells to the ocular surface and anterior segment of the eye. New component-cell corneal transplantation procedures that may reduce the risk of immunological rejection have been developed and are already in clinical practice. Finally, gene therapy is being tested in experimental animals to improve the outcomes of corneal transplantation, and to halt or reverse the pathophysiology of some corneal dystrophies. ... Read more

Personalized Medicine: Theranostics (Therapeutics Diagnostics) Essential for Rational Use of Tumor Necrosis Factor-alpha Antagonists

Abstract: With the discovery of the central pathogenic role of tumor necrosis factor (TNF)-α in many immunoinflammatory diseases, specific inhibition of this pleiotropic cytokine has revolutionized the treatment of patients with several non-infectious inflammatory disorders. As a result, genetically engineered anti-TNF-α antibody constructs now constitute one of the heaviest medicinal expenditures in many countries. All currently used TNF antagonists may dramatically lower disease activity and, in some patients, induce remission. Unfortunately, however, not all patients respond favorably, and safety can be severely impaired by immunogenicity, i.e., the ability of a drug to induce anti-drug antibodies (ADA). Assessment of ADA is therefore an important component of the evaluation of drug safety in both pre-clinical and clinical studies and in the process of developing less immunogenic and safer biopharmaceuticals. Therapeutics diagnostics, also called theranostics, i.e., monitoring functional drug levels and neutralizing ADA in the circulation, is central to more effective use of biopharmaceuticals. Hence, testing-based strategies rather than empirical dose-escalation may provide more cost-effective use of TNF antagonists as this allows therapies tailored according to individual requirements rather than the current universal approach to diagnosis. The objective of the present review is to discuss the reasons for recommending theranostics to implement an individualized use of TNF antagonists and to highlight some of the methodological obstacles that have obscured cost-effective ways of using these therapies. ... Read more

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