Rheumatoid arthritis: Evolving recognition of a common disease

Treatment response in rheumatoid arthritis is predicted by the microbiome: a large observational study in UK DMARD-naive patients

OBJECTIVES

Disease-modifying antirheumatic drugs (DMARDs) are a first-line treatment in rheumatoid arthritis (RA). Treatment response to DMARDs is patient-specific, dose efficacy is difficult to predict and long-term results are variable. The gut microbiota are known to play a pivotal role in prodromal and early-disease RA, manifested by Prevotella spp. enrichment. The clinical response to therapy may be mediated by microbiota, and large-scale studies assessing the microbiome are few. This study assessed whether microbiome signals were associated with, and predictive of, patient response to DMARD treatment. Accurate early identification of those who will respond poorly to DMARD therapy would allow selection of alternative treatment (e.g. biologic therapy) and potentially improve patient outcome.

METHODS

A multicentre, longitudinal, observational study of stool- and saliva microbiome was performed in DMARD-naive, newly diagnosed RA patients during introduction of DMARD treatment. Clinical data and samples were collected at baseline (n = 144) in DMARD-naive patients and at six weeks (n = 117) and 12 weeks (n = 95) into DMARD therapy. Samples collected (n = 365 stool, n = 365 saliva) underwent shotgun sequencing. Disease activity measures were collected at each timepoint and minimal clinically important improvement determined.

RESULTS

In total, 26 stool microbes were found to decrease in those manifesting a minimal clinically important improvement. Prevotella spp. and Streptococcus spp. were the predominant taxa to decline following six weeks and 12 weeks of DMARDs, respectively. Furthermore, baseline microbiota of DMARD-naive patients were indicative of future response.

CONCLUSION

DMARDs appear to restore a perturbed microbiome to a eubiotic state. Moreover, microbiome status can be used to predict likelihood of patient response to DMARD.

Pathophysiology, diagnosis, and herbal medicine-based therapeutic implication of rheumatoid arthritis: an overview

Rheumatoid arthritis (RA) stands as an autoimmune disorder characterized by chronic joint inflammation, resulting in profound physiological alterations within the body. Affecting approximately 0.4-1.3% of the global population, this condition poses significant challenges as current therapeutic approaches primarily offer symptomatic relief, with the prospect of complete recovery remaining elusive. This review delves into the contemporary advancements in understanding the pathophysiology, diagnosis, and the therapeutic potential of herbal medicine in managing RA. Notably, early diagnosis during the initial stages emerges as the pivotal determinant for successful recovery post-treatment. Utilizing tools such as Magnetic Resonance Imaging (MRI), anti-citrullinated peptide antibody markers, and radiography proves crucial in pinpointing the diagnosis of RA with precision. Unveiling the intricate pathophysiological mechanisms of RA has paved the way for innovative therapeutic interventions, incorporating plant extracts and isolated phytoconstituents. In the realm of pharmacological therapy for RA, specific disease-modifying antirheumatic drugs have showcased commendable efficacy. However, this conventional approach is not without its drawbacks, as it is often associated with various side effects. The integration of methodological strategies, encompassing both pharmacological and plant-based herbal therapies, presents a promising avenue for achieving substantive recovery. This integrated approach not only addresses the symptoms but also strives to tackle the underlying causes of RA, fostering a more comprehensive and sustainable path towards healing.

Exploring the mechanism of Celastrol in the treatment of rheumatoid arthritis based on systems pharmacology and multi-omics

To explore the molecular network mechanism of Celastrol in the treatment of rheumatoid arthritis (RA) based on a novel strategy (integrated systems pharmacology, proteomics, transcriptomics and single-cell transcriptomics). Firstly, the potential targets of Celastrol and RA genes were predicted through the database, and the Celastrol-RA targets were obtained by taking the intersection. Then, transcriptomic data and proteomic data of Celastrol treatment of RA were collected. Subsequently, Celastrol-RA targets, differentially expressed genes, and differentially expressed proteins were imported into Metascape for enrichment analysis, and related networks were constructed. Finally, the core targets of Celastrol-RA targets, differentially expressed genes, and differentially expressed proteins were mapped to synoviocytes of RA mice to find potential cell populations for Celastrol therapy. A total of 195 Celastrol-RA targets, 2068 differential genes, 294 differential proteins were obtained. The results of enrichment analysis showed that these targets, genes and proteins were mainly related to extracellular matrix organization, TGF-β signaling pathway, etc. The results of single cell sequencing showed that the main clusters of these targets, genes, and proteins could be mapped to RA synovial cells. For example, Mmp9 was mainly distributed in Hematopoietic cells, especially in Ptprn+fibroblast. The results of molecular docking also suggested that Celastrol could stably combine with molecules predicted by network pharmacology. In conclusion, this study used systems pharmacology, transcriptomics, proteomics, single-cell transcriptomics to reveal that Celastrol may regulate the PI3K/AKT signaling pathway by regulating key targets such as TNF and IL6, and then play an immune regulatory role.

Role of m6A modification and novel circ_0066715/ miR-486-5p/ ETS1 axis in rheumatoid arthritis macrophage polarization progression

Rheumatoid arthritis (RA) is a systemic disease dominated by inflammatory synovitis. RA synovial macrophages tend undergo M1-type macrophage polarization. Then, polarized M1-type macrophages secrete abundant pro-inflammatory cytokines, causing joint and cartilage destruction. N6-methyladenosine (m6A) methylation modification, circular RNA (circRNA), microRNA (miRNA), messenger RNA (mRNA), etc. are involved in the inflammatory response of RA. We found that there is an imbalance of inflammatory polarization in RA, which is manifested by a sharp increase in inflammatory markers and a high inflammatory response. Here, we show that RA was closely associated with low expression of circ_0066715. The overexpression of circ_0066715 significantly increased the ETS1 levels in RA-FLS cells, decreased cytokine secretion by M1-type macrophages, elevated M2-type cytokines, and inhibited FLS proliferation. Interestingly, the overexpression of miR-486-5p significantly suppressed the attenuation of the cell function and the effect on M1 macrophage polarization caused by circ_0066715 positive expression. WTAP may be involved in the methylation process of ETS1 in RA. ETS1 m6A methylation levels were altered upon WTAP intervention. The overexpression or interference of circ_0066715 decreased or increased WTAP expression. Our findings provide a novel circRNA/miRNA/mRNA regulatory axis and m6A regulatory mechanism involved in the process of RA macrophage polarization, thereby providing a powerful diagnostic and therapeutic strategy for RA treatment.

Ziyuglycoside I attenuates collagen-induced arthritis through inhibiting plasma cell expansion

ETHNOBOTANICAL RELEVANCE

With most of the anti-rheumatic drugs having severe adverse drug reactions and poor tolerance, the active components from natural herbs provides a repository for novel, safe, and effective drug development. Sanguisorba officinalis L. exhibits definite anti-inflammatory capacity, however, whether it has anti-rheumatic effects has not been revealed.

AIM OF THE STUDY

In the present study, the effect of Ziyuglycoside I (Ziyu I), one of the most important active components in Sanguisorba officinalis L., was investigated in treating collagen-induced arthritis (CIA), illuminating its potential pharmacological mechanisms.

MATERIAL AND METHODS

CIA mice were treated with 5, 10, or 20 mg/kg of Ziyu I or 2 mg/kg of MTX, and clinical manifestations as well as pathological changes were observed. T and B cell viability was determined using cell counting kit-8, plasma autoantibodies and cytokines were tested with ELISA, T and B cell subsets were identified by flow cytometry, Blimp1 expression was detected by RT-qPCR and in situ immunofluorescence. The expression of activation-induced cytidine deaminase (AID) was detected by immunohistochemistry. ERK activation in B cells was verified through western blotting and immunofluorescence. Meanwhile, bioinformatics retrieval and molecular docking/molecular dynamics were used to predict the relationship between Blimp1, ERK and Ziyu I with the pharmacokinetics and toxicity of Ziyu I being evaluated in the ADMETlab Web platform.

RESULTS

Ziyu I treatment effectively alleviated the joint inflammatory manifestation including arthritis index, global scores, swollen joint count and body weight of CIA mice. It improved the pathological changes of joint and spleen of arthritic mice, especially in germinal center formation. Ziyu I displayed a moderate regulatory effect on T cell activation, the percentage of total T and helper T cells, and tumor necrosis factor-α, but transforming growth factor-β was not restored. Increased spleen index, B cell viability and plasma auto-antibody production in CIA mice were significantly reduced by Ziyu I therapy. Of note, we found that Ziyu I administration substantially inhibited the excessive expansion of plasma cells in spleen through preventing the expression of B lymphocyte induced maturation protein 1 (Blimp1) and AID in B cells. Ziyu I was predicted in silico to directly interact with ERK2, and reduce ERK2 activation, contributing to the depressed expression of Blimp1. Moreover, Ziyu I was predicted to have a favorable pharmacokinetic profile and low toxicity.

CONCLUSION

Ziyu I effectively ameliorates CIA in mice by inhibiting plasma cell generation through prevention of ERK2-mediated Blimp1 expression in B cells. Therefore, Ziyu I is a promising candidate for anti-arthritic drug development.

Serum HDAC4 level in rheumatoid arthritis: Longitudinal change during treatment and correlation with clinical outcomes

Objective

Histone deacetylase 4 (HDAC4) modulates immunity, inflammation, and osteoblast differentiation to engage in rheumatoid arthritis (RA) etiology. This study aimed to evaluate the HDAC4 longitudinal change and its relationship with clinical features and outcomes in RA patients.

Methods

Eighty‐three RA patients were enrolled. Their serum HDAC4 level was detected by ELISA at baseline (W0), week (W) 4, W12, and W24 after treatment. RA patients were divided into response or non‐response, low disease activity (LDA) or non‐LDA, remission or non‐remission patients according to their treatment outcomes at W24. Meanwhile, serum HDAC4 was detected by ELISA in 20 osteoarthritis patients and 20 healthy controls (HCs).

Results

HDAC4 level was reduced in RA patients compared with HCs (p < 0.001) and osteoarthritis patients (p = 0.009). HDAC4 was negatively related to some of the disease activity indexes such as C‐reactive protein (p = 0.003), tender joint count (p = 0.025), and disease activity score based on 28 joints (p = 0.013) in RA patients; it was also negatively correlated with TNF‐α (p = 0.003), IL‐6 (p = 0.022), and IL‐17A (p = 0.015). However, the HDAC4 level was not related to different treatment histories or current initiating treatment regimens (all p < 0.05). After treatment, HDAC4 was gradually elevated along with the time (p < 0.001). Interestingly, HDAC4 level at W12 (p = 0.041) and W24 (p = 0.012) was higher in response patients versus non‐response patients, and its level at W24 was higher in LDA patients versus non‐LDA patients (p = 0.019), and in remission patients versus non‐remission patients (p = 0.039).

Conclusion

HDAC4 gradually increases during treatment and its elevation estimates good treatment outcomes in RA patients.