Cutting Edge: Chronic NF-κB Activation in CD4+ T Cells in Rheumatoid Arthritis Is Genetically Determined by HLA Risk Alleles

Rheumatoid arthritis-recent advances in pathogenesis and the anti-inflammatory effect of plant-derived COX inhibitors

The majority of people with autoimmune disorders, including those with rheumatoid arthritis, osteoarthritis, and tendonitis report pain, stiffness, and inflammation as major contributors to their worse quality of life in terms of overall health. Of all the available treatment options, COX inhibitors are the ones that are utilized most frequently to ease the symptoms. Various signaling cascades have been reported to be involved in the pathogenesis of rheumatoid arthritis which includes JAK/STAT, MAPK, and NF-kB signaling pathways, and several allopathic inhibitors (tofacitinib and baricitinib) have been reported to target the components of these cascades and have received approval for RA treatment. However, the prolonged use of these COX inhibitors and other allopathic drugs can pose serious health challenges due to their significant side effects. Therefore, searching for a more effective and side effect-free treatment for rheumatoid arthritis has unveiled phytochemicals as both productive and promising. Their therapeutic ability helps develop potent and safe drugs targeting immune-inflammatory diseases including RA. Various scientific databases were used for searching articles such as NCBI, SpringerLink, BioMed Central, ResearchGate, Google Scholar, Scopus, Nature, Wiley Online Library, and ScienceDirect. This review lists various phytochemicals and discusses their potential molecular targets in RA treatment, as demonstrated by various in vitro, in vivo (pre-clinical), and clinical studies. Several pre-clinical and clinical studies suggest that various phytochemicals can be an alternative promising intervention for attenuating and managing inflammation-associated pathogenesis of rheumatoid arthritis.

Genetic basis of defects in immune tolerance underlying the development of autoimmunity

Genetic variants associated with susceptibility to autoimmune disease have provided important insight into the mechanisms responsible for the loss of immune tolerance and the subsequent development of autoantibodies, tissue damage, and onset of clinical disease. Here, we review how genetic variants shared across multiple autoimmune diseases have contributed to our understanding of global tolerance failure, focusing on variants in the human leukocyte antigen region, PTPN2 and PTPN22, and their role in antigen presentation and T and B cell homeostasis. Variants unique to a specific autoimmune disease such as those in PADI2 and PADI4 that are associated with rheumatoid arthritis are also discussed, addressing their role in disease-specific immunopathology. Current research continues to focus on determining the functional consequences of autoimmune disease-associated variants but has recently expanded to variants in the non-coding regions of the genome using novel approaches to investigate the impact of these variants on mechanisms regulating gene expression. Lastly, studying genetic risk variants in the setting of autoimmunity has clinical implications, helping predict who will develop autoimmune disease and also identifying potential therapeutic targets.

Therapeutic effects of Chinese medicine Di-Long (Pheretima vulgaris) on rheumatoid arthritis through inhibiting NF-κB activation and regulating Th1/Th2 balance

Chinese medicine Di-Long, the dried body of Pheretima vulgaris (Chen) has been used for the treatment of joint inflammation, arthralgia and numbness of limbs for many years. This study was to investigate the anti-rheumatoid arthritis (RA) effects of Di-Long and to explore its possible mechanisms. The identification and quantification of representative components in Di-Long extracts (DL) were carried out by HPLC analysis. The anti-RA effects and mechanisms of DL were studied in CIA mice, RAW 264.7 macrophages and spleen T lymphocytes. The Th1/Th2 cell ratio in CIA mice spleens were determined by Flow cytometry. The cytokine levels were determined by ELISA method. The expressions of p-NF-κB p65 in ankle joints of CIA mice were detected by Immunohistochemistry analysis. The phosphorylation of NF-κB signaling pathway in RAW 264.7 macrophages and expressions of T-bet and GATA-3 in CIA mice spleens were determined by Western blots. The treatment with DL significantly decreased the paw thickness, arthritis scores and inflammatory cells infiltration in CIA mice. The TNF-α, IL-6 concentrations in both mice serum and macrophages secretion were markedly reduced with the treatment of DL, as well as the phosphorylation of NF-κB pathway. DL inhibited the expressions of T-bet and GATA-3 and decreased Th1/Th2 cells ratio in CIA mice spleens. DL reduced IFN-γ, IL-2 levels in mice serum and spleen T lymphocytes, and increased IL-4 levels in CIA mice serum. Chinese medicine Di-Long have significant anti-RA effects. The mechanisms might be inhibiting the activation of NF-κB signaling pathway and regulating the balance of Th1/Th2 cells.

The genetic pathogenesis, diagnosis and therapeutic insight of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that causes chronic inflammation of the joints. RA is a heterogeneous disorder caused by an abnormal autoimmune response triggered by the complex interactions of genetic and environmental factors that contribute to RA etiology. However, its underlying pathogenic mechanisms are yet to be fully understood. In this review, I provide an overview of the pathogenesis, diagnosis and therapeutic insight in the clinical management of RA in light of the recent updates to classification criteria and recent discoveries of genetic loci associated with susceptibility for RA.

Genetic and environmental risk factors for rheumatoid arthritis

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the "shared epitope," and exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a "preclinical" period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically apparent synovitis and classifiable RA, to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

Inflammation and epigenetic regulation in osteoarthritis

Osteoarthritis (OA) was once defined as a non-inflammatory arthropathy, but it is now well-recognized that there is a major inflammatory component to this disease. In addition to synovial cells, articular chondrocytes and other cells of diarthrodial joints are also known to express inflammatory mediators. It has been proposed that targeting inflammation pathways could be a promising strategy to treat OA. There have been many reports of cross-talk between inflammation and epigenetic factors in cartilage. Specifically, inflammatory mediators have been shown to regulate levels of enzymes that catalyze changes in DNA methylation and histone structure, as well as alter levels of non-coding RNAs. In addition, expression levels of a number of these epigenetic factors have been shown to be altered in OA, thereby suggesting potential interplay between inflammation and epigenetics in this disease. This review provides information on inflammatory pathways in arthritis and summarizes published research on how epigenetic regulators are affected by inflammation in chondrocytes. Furthermore, we discuss data showing how altered expression of some of these epigenetic factors can induce either catabolic or anti-catabolic effects in response to inflammatory signals. A better understanding of how inflammation affects epigenetic factors in OA may provide us with novel therapeutic strategies to treat this condition.

Update on the genetic architecture of rheumatoid arthritis

Human genetic studies into rheumatoid arthritis (RA) have uncovered more than 100 genetic loci associated with susceptibility to RA and have refined the RA-association model for HLA variants. The majority of RA-risk variants are highly shared across multiple ancestral populations and are located in noncoding elements that might have allele-specific regulatory effects in relevant tissues. Emerging multi-omics data, high-density genotype data and bioinformatic approaches are enabling researchers to use RA-risk variants to identify functionally relevant cell types and biological pathways that are involved in impaired immune processes and disease phenotypes. This Review summarizes reported RA-risk loci and the latest insights from human genetic studies into RA pathogenesis, including how genetic data has helped to identify currently available drugs that could be repurposed for patients with RA and the role of genetics in guiding the development of new drugs.

Risk of lymphoid neoplasms in a Swedish population-based cohort of 337,437 patients undergoing appendectomy

OBJECTIVE

Appendectomy remains one of the most common surgical procedures, but possible long-term consequences for health and disease are incompletely investigated. The appendix forms part of the secondary lymphoid system and appendectomy has been associated with increased risks of hematolymphoproliferative malignancies in some studies.

MATERIALS AND METHODS

We examined the risk of lymphoid neoplasms in a large cohort of 337,437 appendectomised patients <60 years of age in Sweden 1975-2009. We estimated relative risks of non-Hodgkin lymphoma (NHL) and major subtypes, Hodgkin lymphoma (HL), chronic lymphocytic leukaemia (CLL), myeloma, and acute lymphoblastic leukaemia (ALL) versus the general population using standardised incidence ratios (SIRs) with 95% confidence intervals (CIs).

RESULTS

There was no increased risk of NHL (SIR = 0.97, 95%CI 0.88-1.06), major NHL subtypes, CLL (SIR = 0.87, 95%CI 0.70-1.06), myeloma (SIR = 1.14, 95%CI 0.96-1.33) or ALL (SIR = 1.10, 95%CI 0.80-1.47) following appendectomy. An increased risk of HL was observed among patients diagnosed with appendicitis (SIR = 1.29, 95%CI 1.07-1.54, p=0.007), especially individuals aged <20 years at surgery (SIR = 1.43, 95%CI 1.11-1.82), and for the nodular sclerosis subtype of HL (SIR = 1.55, 95%CI 1.01-2.27). A marginally increased risk of myeloma was noted among men, but the association was limited to the first few years of follow-up.

CONCLUSION

Appendectomy is not associated with any notable increase in risk of lymphoid neoplasms. A small increased risk of HL following appendicitis (rather than appendectomy per se) could reflect a true association, or shared susceptibility to infection/inflammation among individuals prone to develop HL. The association observed for myeloma may be explained by chance or surveillance bias.

Factors Associated With Pathogenicity of Anti-Glomerular Basal Membrane Antibodies: A Case Report

Antiglomerular basement membrane (GBM) disease is known as a super-acute proliferative glomerulonephritis caused by auto-antibodies targeting the NC1 domain of the α3 chain of type IV collagen.Here, we describe a case of atypical anti-GBM disease presenting as a dialysis-dependent acute renal failure with unusual mild glomerular involvement. We found that immunoglobulin G (IgG) deposits were restricted to the uncommon IgG2 and IgG4 subclasses, and that blood was positive for anti-GBM antibodies by immunofluorescence, but not by Enzyme Linked Immunosorbent Assay (ELISA). The patient was treated with plasma exchanges, corticosteroids, and cyclosphosphamide. He eventually regained a normal renal function.This case demonstrates that biopsy-proven anti-GBM disease can have reduced pathogenicity. Referring to previous studies of anti-GBM detection in the blood from healthy or minimally ill individuals, we discuss the antigenic specificities, the IgG subclasses, and the involvement of complement in this observation.We suggest that anti-GBM disease is a heterogeneous entity and that the study of IgG subclasses by immunofluorescence may help to distinguish categories with different severities.

Effect of Xinfeng capsule on nuclear factor Kappa B/tumor necrosis factor alpha and transforming growth factor beta 1/Smads pathways in rats with cardiac injuries induced by adjuvant arthritis

OBJECTIVE

To investigate effects of Xinfeng capsule (XFC) on cardiac function in rats with adjuvant arthritis (AA) and explore the mechanism of these effects.

METHODS

Forty-eight rats were randomly divided into normal control (NC), model control (MC), methotrexate (MTX) and XFC groups of equal size. In all groups except for the NC group, 0.1 mL Freund's complete adjuvant (FCA) was intracutaneously injected in the right rear vola pedis to induce inflammation. Drugs were applied beginning 19 days after induction of inflammation. Normal saline was administered to the NC and MC groups and 1 mg/ 100 g MTX (weekly) and 0.12 g/100 g XFC (daily) to the MTX and XFC groups, respectively. Rats were sacrificed after 30 day of treatment. Toe swelling degree (TSD), arthritis index (Al), cardiac function and expression of nuclear factor kappa B (NF-κB)/tumor necrosis factor alpha (TNF-α) and transforming growth factor beta 1 (TGF-β1)/Smads pathway proteins were measured.

RESULTS

In the MC group, TSD and Al were greatly increased, while parameters of cardiac function were decreased and morphological analysis showed myocardial cell damage. Expression of TNF-α, NF-KB, Smad2, P-Smad2, Smad4 and TGF-β1 proteins were elevated in cardiac tissue, while Smad7 expression was decreased. TSD and Al values closely correlated to parameters of cardiac function and to levels of proteins in the NF-κB/TNF-α and TGF-β1/Smads pathways. Certain correlations were identified among TGF-β1 and NF-KB, Smad2, P-Smad2 and Smad4. With XFC intervention, both TSD and Al were decreased and parameters of cardiac function and ultrastructure of myocardial cells improved. Expressions of NF-κB, Smad2, and Smad4 proteins were greatly decreased and Smad7 expression was elevated, as compared with levels in the MC and MTX groups.

CONCLUSION

XFC regulates expression of proteins in the NF-KB/TNF-α and TGF-β1/Smads pathways, decreases immune complex deposition in cardiac tissue and improves cardiac function in AA rats via upregulation of Smad7.

Risk Genes of Inflammatory Bowel Disease in Asia: What Are the Most Important Pathways Affected?

Genetic factors play an important role in the pathogenesis of inflammatory bowel disease (IBD), and IBD is now recognized as a complex disease that results from interplay between genetic and environment factors. To date, over 160 IBD-susceptible loci have been identified using genome-wide association studies (GWAS). The risk genes identified in these studies are involved in various pathways in innate and adaptive immune response such as innate bacterial sensing, autophagy and interleukin-23 receptor/T-helper cell 17 pathway. It was initially believed that the genetic backgrounds of Asian IBD patients differ from that of other populations. Recent GWAS and meta-analysis found that there is pervasive sharing of risk loci between the East and West. Overlapping risk genes between populations of different ancestries indicate that pathways underlying the etiology of IBD may be common between Asia and other areas. However, the importance of individual pathways may be different in Asia from the Western countries. Identifying the most important pathways affected in Asian IBD patients may provide a better understanding of pathogenesis of IBD in Asia and improve the clinical management of the patients.

Collagen Specific T-Cell Repertoire and HLA-DR Alleles: Biomarkers of Active Refractory Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by chronic joint inflammation and associates with HLA-DRB1*04. The Collagen IIp_261-273-specific T cell repertoire in the peripheral blood of DR4 + patients at the onset of the disease shows a restricted TCR-beta chain usage among which the most frequent is TRBV25.

To define whether this group of DR4-restricted collagen-specific shared T cell could represent markers of active-severe disease and response to therapy, 90 subjects affected by early-RA were enrolled in the study; peripheral blood mononuclear cells were cultured with or without the human collagen II peptide p261-273 and were examined by immunoscope analysis for the usage of the previously identified shared TCR-beta chains.

We report that the presence of T cells carrying rearrangement TRBV25 associated with HLA-DR haplotype and disease activity. HLA-DRB1* haplotypes 04–04, 04–01 and 04–11 were significantly associated with usage of TRBV25, higher disease activity at the onset of disease and poor response to DMARDs.

Finally, the HLA-DRB1* haplotype appeared complementary with current serologic tools to predict good and poor responders in a treat to target strategy. The data reported here offer clues to predict the course of the disease and to foresee personalized treatments in RA patients.

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In DR4 + RA patients disease activity is associated with detection of Collagen_261-273-specific T cells carrying TRBV25.

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HLA-DR 04/04, 04/01 and 04/11 alleles were associated with TRBV25, DAS at the onset, and poor response to DMARDs.

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These findings could lead to tailor the treatment in the subgroup of patients with an active refractory disease.

In the era of costly medical care with monoclonal antibodies and new molecules, and of an increasing request of a personalized medicine, a relevant socio-economic problem in the management of Rheumatoid Arthritis patients is the possible identification of the subgroups of poor responders to treatment. Our study aimed to detect the refractory active patients using an HLA-DR test (available in most hospital centers) combined with a relatively new biomarker of active disease expressed on the cell surface of autoreactive T cells. These tests appear complementary tools to identify the best and the poor responders to a “treat to target strategy”.