New Targets and Strategies for Rheumatoid Arthritis: From Signal Transduction to Epigenetic Aspect

Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Combined With Network Pharmacology to Elucidate the Bioactive Ingredients and Potential Mechanism of Wu-Teng Decoction for Treatment of Rheumatoid Arthritis

Wu-Teng Decoction (WTD) is a significant in-hospital preparation widely used in clinical practice to treat rheumatoid arthritis (RA) in China, however, its active substances and underlying mechanisms remain unclear. In this study, the chemical constituents of WTD were analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry, identifying a total of 120 compounds, including flavonoids, phenylpropanoids, phenolic acids, alkaloids, etc. Subsequently, network pharmacology analyses revealed that 29 compounds were potential active compounds in WTD for the treatment of RA, as well as 48 core anti-RA targets, including tumor necrosis factor-α, V-Akt murine thymoma viral oncogene homolog 1, and albumin. Further analysis suggested that WTD treats RA via the phosphoinositide 3-kinase-Akt, mitogen-activated protein kinase, and Ras signaling pathways. Molecular docking analysis of the top five pivotal targets with the core active ingredients demonstrated suitable binding interactions at the active site of target proteins. The significant reduction of nitric oxide levels in lipopolysaccharides-induced RAW264.7 cells validated the anti-inflammation activity of WTD.

FOXA2 inhibits the TLR4/NF-κB signaling pathway and alleviates inflammatory activation of macrophages in rheumatoid arthritis by repressing LY96 transcription

BACKGROUND

Rheumatoid arthritis (RA) remains a devastating autoimmune disease characterized by joint damage, inflammation, and disability. This study investigates the function of lymphocyte antigen 96 (LY96) in the inflammatory response in RA and explores its regulatory mechanism.

METHODS

A mouse model of RA was developed using type II collagen, and the LY96 expression in the ankle joint tissue was determined. Upstream regulators targeting LY96 were investigated using bioinformatics, followed by chromatin immunoprecipitation and luciferase reporter assays for validation. Gain- or loss-of-functions of LY96 and forkhead box A2 (FOXA2) were performed to analyze their roles in arthritis score, pathological changes, and inflammatory responses in mice. The effects of FOXA2 and LY96 on pro-inflammatory activation of macrophages were additionally investigated in vitro using a mouse RAW264.7 macrophage model with lipopolysaccharide treatment.

RESULTS

LY96 mRNA and protein (MD-2) levels were increased in the RA mice. Knockdown of LY96 alleviated arthritis severity, joint deformities, inflammation, and cartilage destruction in mice. In vitro, the LY96 knockdown reduced the pro-inflammatory activation of RAW264.7 macrophages by inhibiting the TLR4/NF-κB inflammatory signaling transduction. FOXA2 was identified as a transcriptional repressor of LP96 poorly expressed in RA. Overexpression of FOXA2 similarly alleviated inflammation and reduced M1-type macrophages in vivo and in vitro. However, these changes were reversed by the additional LY96 upregulation.

CONCLUSION

This study suggests that FOXA2 represses LY96 transcription to inhibit the TLR4/NF-κB signaling transduction, thus reducing pro-inflammatory activation of macrophages in the context of RA.

High Humidity Alters Myeloid-Derived Suppressor Cells in Spleen Tissue: Insights into Rheumatoid Arthritis Progression

Background

Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation and bone destruction, leading to severe complications. Previous research has suggested that high humidity conditions may exacerbate RA, however, the underlying mechanisms remain unclear. Furthermore, there is a lack of evidence linking humidity to the worsening of RA symptoms in animal models.

Methods

The Collagen-induced arthritis (CIA) mouse model was established using C57BL/6 mice. The arthritis status of the mice was evaluated under two distinct humidity conditions (50% and 80%). The aim of the present study was to investigate the impact of elevated humidity levels on the types of splenic cells present using mass spectrometry flow. Additionally, the study utilized MDSCs, which are significantly upregulated by high humidity, to assess the levels of oxidative stress and conducted mRNA sequencing of sorted MDSCs to investigate their impact on arthritis in CIA mice.

Results

Compared to normal humidity, high humidity exacerbated arthritis incidence in mice, resulting in increased arthritis scores, swelling, serum autoantibodies (anti-COII and anti-CCP), and upregulation of pro-inflammatory cytokines. Significant variations were observed in the spleen index under high humidity condition, accompanied by noticeable inflammatory alterations. Moreover, elevated humidity levels induced a substantial modulation in MDSCs population in the spleen of CIA mice, along with alterations in oxidative stress markers such as heightened serum ROS levels, and increased expression of COX, SOD, and Nrf2 mRNA. Following successful sorting of MDSCs, mRNA sequencing revealed a decrease in the expression of Rap1 signaling pathway under high humidity environment, which may contribute to the increase of MDSCs cells and aggravate the progression of RA disease.

Conclusion

A comprehensive analysis of the available data reveals a detrimental impact of high humidity on MDSCs numbers within spleen tissue, with potential implications for the development of RA.

Genetics, epigenetics and autoimmunity constitute a Bermuda triangle for the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA), a multigene disorder with a heritability rate of 60 %, is characterized by persistent pain, synovial hyperplasia, and cartilage and bone destruction, ultimately causing irreversible joint deformity. The etiology and pathogenesis of rheumatoid arthritis (RA) are primarily influenced by specific genetic variants, particularly HLA alleles such as HLA-DRB1*01 and DRB1*04. However, other HLA alleles such as HLA-DRB1*10 and DPB*1 have also been found to contribute to increased susceptibility to RA. However, non-HLA genes also confer a comparatively high risk of RA disease manifestation. The most relevant single nucleotide polymorphisms (SNPs) associated with non-HLA genes are PTPN22, TRAF1, CXCL-12, TBX-5, STAT4, FCGR, PADI4, and MTHFR. In conjunction with genetic susceptibility, epigenetic alterations orchestrate paramount involvement in regulating RA pathogenesis. Increasing evidence implicates DNA methylation and histone protein modifications, including acetylation and methylation, as the primary epigenetic mechanisms that drive the pathogenesis and clinical progression of the disease. In addition to genetic and epigenetic changes, autoimmune inflammation also determines the pathological progression of the synovial membrane in joints with RA. Glycosylation changes, such as sialylation and fucosylation, in immune cells have been shown to be relevant to disease progression. Genetic heterogeneity, epigenetic factors, and changes in glycosylation do not fully explain the features of RA. Therefore, investigating the interplay between genetics, epigenetics, and autoimmunity is crucial. This review highlights the significance and interaction of these elements in RA pathophysiology, suggesting their diagnostic potential and opening new avenues for novel therapeutic approaches.

PANoptosis in autoimmune diseases interplay between apoptosis, necrosis, and pyroptosis

PANoptosis is a newly identified inflammatory programmed cell death (PCD) that involves the interplay of apoptosis, necrosis, and pyroptosis. However, its overall biological effects cannot be attributed to any one type of PCD alone. PANoptosis is regulated by a signaling cascade triggered by the recognition of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) by various sensors. This triggers the assembly of the PANoptosome, which integrates key components from other PCD pathways via adapters and ultimately activates downstream execution molecules, resulting in cell death with necrotic, apoptotic, and pyroptotic features. Autoimmune diseases are characterized by reduced immune tolerance to self-antigens, leading to abnormal immune responses, often accompanied by systemic chronic inflammation. Consequently, PANoptosis, as a unique innate immune-inflammatory PCD pathway, has significant pathophysiological relevance to inflammation and autoimmunity. However, most previous research on PANoptosis has focused on tumors and infectious diseases, leaving its activation and role in autoimmune diseases unclear. This review briefly outlines the characteristics of PANoptosis and summarizes several newly identified PANoptosome complexes, their activation mechanisms, and key components. We also explored the dual role of PANoptosis in diseases and potential therapeutic approaches targeting PANoptosis. Additionally, we review the existing evidence for PANoptosis in several autoimmune diseases and explore the potential regulatory mechanisms involved.

Nature of the Association between Rheumatoid Arthritis and Cervical Cancer and Its Potential Therapeutic Implications

It is now established that patients with rheumatoid arthritis (RA) have an increased risk of developing cervical cancer (CC) or its precursor, cervical intraepithelial neoplasia (CIN). However, the underlying mechanisms of this association have not been elucidated. RA is characterized by unresolved chronic inflammation. It is suggested that human papillomavirus (HPV) infection in RA patients exacerbates inflammation, increasing the risk of CC. The tumor microenvironment in RA patients with CC is also marked by chronic inflammation, which aggravates the manifestations of both conditions. Gut and vaginal dysbiosis are also considered potential mechanisms that contribute to the chronic inflammation and aggravation of RA and CC manifestations. Numerous clinical and pre-clinical studies have demonstrated the beneficial effects of various nutritional approaches to attenuate chronic inflammation, including polyunsaturated fatty acids and their derivatives, specialized pro-resolving mediators (SPMs), probiotics, prebiotics, and certain diets. We believe that successful resolution of chronic inflammation and correction of dysbiosis, in combination with current anti-RA and anti-CC therapies, is a promising therapeutic approach for RA and CC. This approach could also reduce the risk of CC development in HPV-infected RA patients.

Recent innovations in topical delivery for management of rheumatoid arthritis: A focus on combination drug delivery

Rheumatoid arthritis (RA) is an immune-mediated disease that necessitates a thorough understanding of its intricate pathophysiological mechanism for precise and effective therapeutic targeting. The European League Against Rheumatism (EULAR) has established guidelines for RA treatment, endorsing monotherapy or combination therapy with corticosteroids and synthetic disease-modifying antirheumatic drugs (sDMARDs). This review delves into clinical trials and research outcomes related to combination drug delivery, with an emphasis on the role of natural products in combination with synthetic drugs. Given the significant adverse effects associated with systemic administration, topical delivery has emerged as an alternative avenue for effective management of RA.

Circulating MicroRNAs and Cytokines Associated with Celiac Disease

BACKGROUND

The current research examines the molecular terrain of celiac disease (CD) through microRNA (miRNA) and cytokines as potential new diagnostic and therapeutic markers. Gluten-appropriate immune response is a key feature of an autoimmune clinical entity known as CD that leads to inflammation and degeneration of small intestine mucosa. However, the mechanisms responsible for this remain unclear.

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR ) was carried out on serum samples obtained from patients with CD and control groups to unravel their pathogenesis. Assessing miR-155, miR-15b, interleukin (IL)-2, IL-7, IL-35and IL-37 levels in expression might be useful in diagnosing or treating the disorder.

RESULTS

A significant dysregulation of these molecular players in patients with CD compared with healthy controls has been evidenced by results from this study. For instance, miR-155 was up-regulated, whereas miR-15b was significantly down-regulated in CD, illustrating their roles in immune responses and inflammation-mediated processes. Besides, there was an over-expression of IL-2 and an under-expression of IL-37 in patients with CD, indicating these biomolecules' role in immuno-dysregulation and inflammatory process underlying CD. In addition, a positive correlation between IL-2 and miRNA 155 expression levels was observed in patients with CD, suggesting that they could be involved together with other cytokines, showing the interplay between immune response pathways and inflammatory cascades during CD pathogenesis.

CONCLUSION

These molecular signature discoveries might result in new and revolutionary diagnostic modalities and molecular-targeted therapies for CD pathogenesis. When used with the scientific understanding of miRNAs and cytokines associated with CD pathophysiology, it creates a basis for personalized medicine based on the individualized molecular profile of all patients. This will undoubtedly increase the efficacy of CD treatment strategies. In brief, more research on molecular pathways' workings should be done to harness their potential in CD diagnosis and treatment.

PTEN: an emerging target in rheumatoid arthritis?

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a critical tumor suppressor protein that regulates various biological processes such as cell proliferation, apoptosis, and inflammatory responses by controlling the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PI3K/AKT) signaling pathway. PTEN plays a crucial role in the pathogenesis of rheumatoid arthritis (RA). Loss of PTEN may contribute to survival, proliferation, and pro-inflammatory cytokine release of fibroblast-like synoviocytes (FLS). Also, persistent PI3K signaling increases myeloid cells' osteoclastic potential, enhancing localized bone destruction. Recent studies have shown that the expression of PTEN protein in the synovial lining of RA patients with aggressive FLS is minimal. Experimental upregulation of PTEN protein expression could reduce the damage caused by RA. Nonetheless, a complete comprehension of aberrant PTEN drives RA progression and its interactions with other crucial molecules remains elusive. This review is dedicated to promoting a thorough understanding of the signaling mechanisms of aberrant PTEN in RA and aims to furnish pertinent theoretical support for forthcoming endeavors in both basic and clinical research within this domain.

Rheumatoid Arthritis Treatment Potential of Stearic Acid Nanoparticles of Quercetin in Rats

This study aims to assess the anti-inflammatory potential of stearic acid nanoparticles of quercetin in an arthritic rat model. This article describes the fabrication of solid lipid nanoparticles (SLNs) using the hot melt encapsulation method, followed by the anti-inflammatory study of SLNs and other characterizations such as FTIR, XRD, and SEM. Thirty male healthy albino rats were taken and treated with FCA to induce rheumatoid arthritis. Quercetin loading of quercetin to stearic acid was confirmed by FTIR. The efficacy of quercetin-loaded SLNs to reduce inflammation was evaluated with the help of inflammatory biomarker levels. Quercetin-loaded stearic acid nanoparticles were successfully prepared by using a hot melt encapsulation method. Their average size and zeta potential were 100 nm and -25 mV, respectively. Rheumatoid arthritis was significantly (p < 0.001) reduced in the quercetin-loaded SLN group, as indicated by finding out the reduced levels of inflammatory mediators such as tumor necrosis factor (TNF-α) and rheumatoid factor. Quercetin-loaded stearic acid nanoparticles were found to be potentially effective in treating RA.

Clinical significance of long non-coding RNA NORAD in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that may cause joint deformities and seriously affect the normal life of the patients. In order to enable patients to receive timely attention and treatment, this study developed new diagnostic markers by exploring the expression and molecular mechanism of the long non-coding RNA NORAD (NORAD) in RA.

METHODS

Participants including 77 RA patients and 52 healthy persons were enrolled, and the corresponding clinical data and serum samples were obtained. The NORAD and miR-204-5p expression were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). The content of inflammatory cytokines (IL-6, TNF-α) were determined through enzyme-linked immunosorbent assay (ELISA). Luciferase activity reporter assay demonstrated the association between NORAD and miR-204-5p. In addition, receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of NORAD, and Pearson's correlation analysis was applied for the correlation analysis.

RESULTS

NORAD was enriched in RA serum with high diagnostic value. Simultaneously, IL-6 and TNF-α levels were also upregulated (P < 0.001). The C-reactive protein (CRP), rheumatoid factor (RF), erythrocyte sedimentation rate (ESR) and anti-cyclic citrullinated peptide antibody (Anti-CCP) levels in RA patients were generally elevated (P < 0.001). NORAD was positively correlated with the levels of clinical indicators and inflammatory factors (P < 0.0001). Mechanistically, NORAD may affect the progression of RA by targeting and negatively regulating miR-204-5p.

CONCLUSIONS

There is a correlation between NORAD and the processes of RA, and NORAD has the potential to predict and diagnose the occurrence of RA.

Deacetylation of Histones and Non-histone Proteins in Inflammatory Diseases and Cancer Therapeutic Potential of Histone Deacetylase Inhibitors

Epigenetic changes play an important role in the pathophysiology of autoimmune diseases such as allergic asthma, multiple sclerosis, lung diseases, diabetes, cystic fibrosis, atherosclerosis, rheumatoid arthritis, and COVID-19. There are three main classes of epigenetic alterations: post-translational modifications of histone proteins, control by non-coding RNA and DNA methylation. Since histone modifications can directly affect chromatin structure and accessibility, they can regulate gene expression levels. Abnormal expression and activity of histone deacetylases (HDACs) have been reported in immune mediated diseases. Increased acetylated levels of lysine residues have been suggested to be related to the overexpression of inflammatory genes. This review focuses on the effect of HDAC modifications on histone and non-histone proteins in autoimmune diseases. Furthermore, we discuss the potential therapeutic effect of HDAC inhibitors (HDACi) used in these diseases.

Rheumatoid Arthritis Has Won the Battle but Not the War: How Many Joints Will We Save Tomorrow?

Rheumatoid arthritis refers to joint diseases of unclear etiology whose final stages can lead to unbearable pain and complete immobility of the affected joints. As one of the most widely known diseases of the joints, it serves as a study target for a large number of research groups and pharmaceutical companies. Modern treatment with anti-inflammatory drugs, including janus kinase (JAK) inhibitors, monoclonal antibodies, and botanicals (polyphenols, glycosides, alkaloids, etc.) has achieved some success and hope for improving the course of the disease. However, existing drugs against RA have a number of side effects which push researchers to elaborate on more selective and effective drug candidates. The avant-garde of research, which aims to develop treatment of rheumatoid arthritis using antisense oligonucleotides along with nonsteroidal drugs and corticosteroids against inflammation, increases the chances of success and expands the arsenal of drugs. The primary goal in the treatment of this disease is to find therapies that allow patients with rheumatoid arthritis to move their joints without pain. The main purpose of this review is to show the victories and challenges for the treatment of rheumatoid arthritis and the tortuous but promising path of research that aims to help patients experience the joy of freely moving joints without pain.

An Update on the Emerging Role of Wnt/β-catenin, SYK, PI3K/AKT, and GM-CSF Signaling Pathways in Rheumatoid Arthritis

Rheumatoid arthritis is an untreatable autoimmune disorder. The disease is accompanied by joint impairment and anomalies, which negatively affect the patient's quality of life and contribute to a decline in manpower. To diagnose and treat rheumatoid arthritis, it is crucial to understand the abnormal signaling pathways that contribute to the disease. This understanding will help develop new rheumatoid arthritis-related intervention targets. Over the last few decades, researchers have given more attention to rheumatoid arthritis. The current review seeks to provide a detailed summary of rheumatoid arthritis, highlighting the basic description of the disease, past occurrences, the study of epidemiology, risk elements, and the process of disease progression, as well as the key scientific development of the disease condition and multiple signaling pathways and enumerating the most current advancements in discovering new rheumatoid arthritis signaling pathways and rheumatoid arthritis inhibitors. This review emphasizes the anti-rheumatoid effects of these inhibitors [for the Wnt/β-catenin, Phosphoinositide 3-Kinases (PI3K/AKT), Spleen Tyrosine Kinase (SYK), and Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) signaling pathways], illustrating their mechanism of action through a literature search, current therapies, and novel drugs under pre-clinical and clinical trials.