Pathogenetic insights from the treatment of rheumatoid arthritis

Mechanism of lysine oxidase-like 1 promoting synovial inflammation mediating rheumatoid arthritis development

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that causes great distress to patients and society. Early diagnosis is the key to the successful treatment of RA. The basement membrane, one of the oldest tissue structures, is localized under the epithelium. Its complex composition and rich biological functions have made it a focus of research in recent years, while basement membrane-associated genetic variants are involved in most human disease processes. The aim of this study is to find new diagnostic biomarkers for RA and explore their role and possible mechanism in rheumatoid arthritis. The GSE12021, GSE55235 and GSE55457 datasets were downloaded from the GEO database. Their fraction associated with basement membrane genes was analyzed and differentially expressed genes between the disease and normal groups were explored. We identified two basement membrane-associated genes, lysine oxidase-like 1 (LOXL1) and discoid peptide receptor 2 (DDR2). Focusing on the more interesting LOXL1, we found that LOXL1 expression was significantly elevated in the synovium of patients with rheumatoid arthritis, and LOXL1 mRNA and protein levels were elevated in tumor necrosis factor α-stimulated human synovial sarcoma cells (SW982). And LOXL1 knockdown inhibited tumor necrosis factor α-induced inhibition in SW982 cells expression of inducible nitric oxide synthase (INOS), cyclooxygenase-2 (COX2), and interleukin-6 (IL-6). Interestingly, knockdown of LOXL1 inhibited the phosphorylation of PI3K and AKT. In summary, LOXL1 may become a novel diagnostic gene for RA, and knockdown of LoxL1 may inhibit synovial inflammation by affecting PI3K/AKT pathway.

Bioresponsive Cytokine Delivery Responding to Matrix Metalloproteinases

Cytokines are regulated in acute and chronic inflammation, including rheumatoid arthritis (RA) and myocardial infarction (MI). However, the dynamic windows within which cytokine activity/inhibition is desirable in RA and MI change timely and locally during the disease. Therefore, traditional, static delivery regimens are unlikely to meet the idiosyncrasy of these highly dynamic pathophysiological and individual processes. Responsive delivery systems and biomaterials, sensing surrogate markers of inflammation (i.e., matrix metalloproteinases - MMPs) and answering with drug release, may present drug activity at the right time, manner, and place. This article discusses MMPs as surrogate markers for disease activity in RA and MI to clock drug discharge to MMP concentration profiles from MMP-responsive drug delivery systems and biomaterials.

Bisdemethoxycurcumin, a curcumin derivative, ameliorates adjuvant-induced arthritis by suppressing inflammatory reactions and macrophage migration

Rheumatoid arthritis (RA) is a highly prevalent and chronic inflammatory synovial joint disease manifested by hyperplasia and continuous inflammation. Curcumin (Cur) has been studied for alleviating RA. However, poor stability and oral bioavailability restrict its therapeutic value. Bisdemethoxycurcumin (BDMC), a curcumin (Cur) derivative, exerts better stability and oral bioavailability than Cur. However, the efficacy of BDMC on RA has not been fully clarified. The aim of the study was to investigate the therapeutic effects and underlying mechanisms of BDMC on RA. The in-vivo anti-arthritic activity of BDMC was determined via adjuvant-induced arthritis (AIA) rat model. Paw swelling, body weight, arthritic index, and histopathological assessments were performed. RAW264.7 cell was stimulated by lipopolysaccharides (LPS) in vitro. The cell viability were determined by CCK8 assay, while the migration ability was determined using cell wound healing and transwell assays. Furthermore, in-vivo and in-vitro levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) were assayed by ELISA, and that of IκBα, p-NF-κB, NF-κB, and COX-2 were assessed via Western blot or immunofluorescence. In AIA rat model, it suggested a higher anti-arthritic activity of BDMC than Cur, including amelioration of swelling in hind paws, reduced arthritic index, and alleviated histopathological injury in rats. Furthermore, BDMC also substantially decreased the levels of the aforementioned pro-inflammatory cytokines in both in-vivo and in-vitro, inhibited the IκBα degradation, down-regulated the COX-2 levels and p-NF-κB/NF-κB ratio in AIA rats and LPS-stimulated RAW264.7 cells. Additionally, BDMC showed an inhibitory effect on the migration of LPS-stimulated RAW264.7 cells. BDMC could effectively ameliorate RA by suppressing inflammatory reactions and inhibiting macrophage migration, more potentially than Cur.

Relationship of weight change patterns from young to middle adulthood with incident rheumatoid arthritis and osteoarthritis: a retrospective cohort study

Background

The relationship between weight change patterns and arthritis onset, specifically rheumatoid arthritis (RA) and osteoarthritis (OA), is unclear. We examined the association between weight changes from young adulthood to midlife and arthritis onset.

Methods

Using data from NHANES 1999-2018, participants with self-reported arthritis were selected. Age at diagnosis determined arthritis onset. Weight change patterns were based on BMI at age 25 and 10 years before the survey. Patterns were categorized as stable non-obese, non-obese to obese, obese to non-obese, and stable obese. Cox regression models and restricted cubic spline (RCS) analysis were employed, calculating hazard ratios (HRs) and 95% confidence intervals (CIs) considering covariates.

Results

Out of 20,859 participants (male 11,017, 52.82%), 4922 developed arthritis over a mean 8.66-year follow-up. Compared to stable non-obese individuals, the HRs for arthritis were 1.55 (95% CI=1.45 to 1.66, P < 0.0001) for non-obese to obese and 1.74 (95% CI=1.56 to 1.95, P < 0.0001) for stable obese. Those gaining 10-20 kg had a HR of 1.33 (95% CI=1.22 to 1.46, P < 0.0001), and gains >20 kg had a HR of 1.56 (95% CI=1.42 to 1.71, P < 0.0001), compared to stable weight (change within 2.5 kg). Identical results observed for OA and RA. RCS showed a nonlinear relationship between weight change and arthritis (all P < 0.01).

Conclusions

Stable obesity and weight gain during adulthood increase arthritis risk. Maintaining a non-obese weight throughout adult years might reduce arthritis risk in later life.

L-arginine metabolism inhibits arthritis and inflammatory bone loss

OBJECTIVES

To investigate the effect of the L-arginine metabolism on arthritis and inflammation-mediated bone loss.

METHODS

L-arginine was applied to three arthritis models (collagen-induced arthritis, serum-induced arthritis and human TNF transgenic mice). Inflammation was assessed clinically and histologically, while bone changes were quantified by μCT and histomorphometry. In vitro, effects of L-arginine on osteoclast differentiation were analysed by RNA-seq and mass spectrometry (MS). Seahorse, Single Cell ENergetIc metabolism by profilIng Translation inHibition and transmission electron microscopy were used for detecting metabolic changes in osteoclasts. Moreover, arginine-associated metabolites were measured in the serum of rheumatoid arthritis (RA) and pre-RA patients.

RESULTS

L-arginine inhibited arthritis and bone loss in all three models and directly blocked TNFα-induced murine and human osteoclastogenesis. RNA-seq and MS analyses indicated that L-arginine switched glycolysis to oxidative phosphorylation in inflammatory osteoclasts leading to increased ATP production, purine metabolism and elevated inosine and hypoxanthine levels. Adenosine deaminase inhibitors blocking inosine and hypoxanthine production abolished the inhibition of L-arginine on osteoclastogenesis in vitro and in vivo. Altered arginine levels were also found in RA and pre-RA patients.

CONCLUSION

Our study demonstrated that L-arginine ameliorates arthritis and bone erosion through metabolic reprogramming and perturbation of purine metabolism in osteoclasts.

Synovial microenvironment-influenced mast cells promote the progression of rheumatoid arthritis

Mast cells are phenotypically and functionally heterogeneous, and their state is possibly controlled by local microenvironment. Therefore, specific analyses are needed to understand whether mast cells function as powerful participants or dispensable bystanders in specific diseases. Here, we show that degranulation of mast cells in inflammatory synovial tissues of patients with rheumatoid arthritis (RA) is induced via MAS-related G protein-coupled receptor X2 (MRGPRX2), and the expression of MHC class II and costimulatory molecules on mast cells are upregulated. Collagen-induced arthritis mice treated with a combination of anti-IL-17A and cromolyn sodium, a mast cell membrane stabilizer, show significantly reduced clinical severity and decreased bone erosion. The findings of the present study suggest that synovial microenvironment-influenced mast cells contribute to disease progression and may provide a further mast cell-targeting therapy for RA.

Network Pharmacology and Experimental Validation Explore the Pharmacological Mechanisms of Herb Pair for Treating Rheumatoid Arthritis

OBJECTIVE

This study aimed to elucidate the multitarget mechanism of the Mori Ramulus - Taxilli Herba (MT) herb pair in treating rheumatoid arthritis (RA).

METHODS

The targets of the herb pair and RA were predicted from databases and screened through cross-analysis. The core targets were obtained using protein-protein interaction (PPI) network analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed. Finally, animal experiments were conducted to validate the anti-RA effect and mechanism of this herb pair.

RESULTS

This approach successfully identified 9 active compounds of MT that interacted with 6 core targets (AKT1, TNF, IL6, TP53, VEGFA, and IL1β). Pathway and functional enrichment analyses revealed that MT had significant effects on the TNF and IL-17 signaling pathways. The consistency of interactions between active components and targets in these pathways was confirmed through molecular docking. Moreover, the potential therapeutic effect of MT was verified in vivo, demonstrating its ability to effectively relieve inflammation by regulating these targeted genes and pathways.

CONCLUSION

The present work suggests that the therapeutic effect of MT herb pair on RA may be attributed to its ability to regulate the TNF signaling pathway and IL-17 signaling pathway.

The Lnc-ENST00000602558/IGF1 axis as a predictor of response to treatment with tripterygium glycosides in rheumatoid arthritis patients

AIMS

Growing clinical evidence suggests that not all patients with rheumatoid arthritis (RA) benefit to the same extent by treatment with tripterygium glycoside (TG), which highlights the need to identify RA-related genes that can be used to predict drug responses. In addition, single genes as markers of RA are not sufficiently accurate for use as predictors. Therefore, there is a need to identify paired expression genes that can serve as biomarkers for predicting the therapeutic effects of TG tablets in RA.

METHODS

A total of 17 pairs of co-expressed genes were identified as candidates for predicting an RA patient's response to TG therapy, and genes involved in the Lnc-ENST00000602558/GF1 axis were selected for that purpose. A partial-least-squares (PLS)-based model was constructed based on the expression levels of Lnc-ENST00000602558/IGF1 in peripheral blood. The model showed high efficiency for predicting an RA patient's response to TG tablets.

RESULTS

Our data confirmed that genes co-expressed in the Lnc-ENST00000602558/IGF1 axis mediate the efficacy of TG in RA treatment, reduce tumor necrosis factor-α induced IGF1 expression, and decrease the inflammatory response of MH7a cells.

CONCLUSION

We found that genes expressed in the Lnc-ENST00000602558/IGF1 axis may be useful for identifying RA patients who will not respond to TG treatment. Our findings provide a rationale for the individualized treatment of RA in clinical settings.

Liposomal AntagomiR-155-5p Restores Anti-Inflammatory Macrophages and Improves Arthritis in Preclinical Models of Rheumatoid Arthritis

OBJECTIVE

We previously reported an increased expression of microRNA-155 (miR-155) in the blood monocytes of patients with rheumatoid arthritis (RA) that could be responsible for impaired monocyte polarization to anti-inflammatory M2-like macrophages. In this study, we employed two preclinical models of RA, collagen-induced arthritis and K/BxN serum transfer arthritis, to examine the therapeutic potential of antagomiR-155-5p entrapped within PEGylated (polyethylene glycol [PEG]) liposomes in resolution of arthritis and repolarization of monocytes towards the anti-inflammatory M2 phenotype.

METHODS

AntagomiR-155-5p or antagomiR-control were encapsulated in PEG liposomes of 100 nm in size and -10 mV in zeta potential with high antagomiR loading efficiency (above 80%). Mice were injected intravenously with 1.5 nmol/100 μL PEG liposomes containing antagomiR-155-5p or control after the induction of arthritis.

RESULTS

We demonstrated the biodistribution of fluorescently tagged PEG liposomes to inflamed joints one hour after the injection of fluorescently tagged PEG liposomes, as well as the liver's subsequent accumulation after 48 hours, indicative of hepatic clearance, in mice with arthritis. The injection of PEG liposomes containing antagomiR-155-5p decreased arthritis score and paw swelling compared with PEG liposomes containing antagomiR-control or the systemic delivery of free antagomiR-155-5p. Moreover, treatment with PEG liposomes containing antagomiR-155-5p led to the restoration of bone marrow monocyte defects in anti-inflammatory macrophage differentiation without any significant functional change in other immune cells, including splenic B and T cells.

CONCLUSION

The injection of antagomiR-155-5p encapsulated in PEG liposomes allows the delivery of small RNA to monocytes and macrophages and reduces joint inflammation in murine models of RA, providing a promising strategy in human disease.

Forsythiaside A exhibits anti-migration and anti-inflammation effects in rheumatoid arthritis in vitro model

BACKGROUND

Rheumatoid arthritis (RA) is a kind of systemic autoimmune disease, and the joint inflammation and cartilage destruction are the major features. Some traditional Chinese medicine have been discovered to exhibit regulatory roles in the treatment of RA. Forsythiaside A (FA) as an active ingredient isolated from forsythia suspensa has been discovered to participate into the regulation of some diseases through improving inflammation. However, the regulatory effects of FA on the progression of RA keep indistinct.

METHODS

IL-1β treatment (10 ng/mL) in MH7A cells was built to mimic RA in vitro (cell) model. The cell viability was examined through CCK-8 assay. The cell proliferation was detected through Edu assay. The levels of TNF-α, IL-6, and IL-8 were evaluated through ELISA. The protein expressions were measured through western blot. The cell apoptosis was assessed through flow cytometry. The cell migration and invasion abilities were tested through Transwell assay.

RESULTS

In this study, it was revealed that the cell proliferation was strengthened after IL-1β treatment (p < .001), but this effect was reversed after FA treatment in a dose-increasing manner (p < .05). Furthermore, FA suppressed inflammation in IL-1β-triggered MH7A cells through attenuating the levels of TNF-α, IL-6, and IL-8 (p < .05). The cell apoptosis was lessened after IL-1β treatment (p < .001), but this effect was rescued after FA treatment (p < .05). Besides, the cell migration and invasion abilities were both increased after IL-1β treatment (p < .001), but these changes were offset after FA treatment (p < .05). Eventually, FA retarded the JAK/STAT pathway through reducing p-JAK/JAK and p-STAT/STAT levels (p < .01).

CONCLUSION

Our study manifested that FA exhibited anti-migration and anti-inflammation effects in RA in vitro model (IL-1β-triggered MH7A cells) through regulating the JAK/STAT pathway. This work hinted that FA can be an effective drug for RA treatment.

Plant-Based Approaches for Rheumatoid Arthritis Regulation: Mechanistic Insights on Pathogenesis, Molecular Pathways, and Delivery Systems

Rheumatoid arthritis (RA) is classified as a chronic inflammatory autoimmune disorder, associated with a varied range of immunological changes, synovial hyperplasia, cartilage destructions, as well as bone erosion. The infiltration of immune-modulatory cells and excessive release of proinflammatory chemokines, cytokines, and growth factors into the inflamed regions are key molecules involved in the progression of RA. Even though many conventional drugs are suggested by a medical practitioner such as DMARDs, NSAIDs, glucocorticoids, etc., to treat RA, but have allied with various side effects. Thus, alternative therapeutics in the form of herbal therapy or phytomedicine has been increasingly explored for this inflammatory disorder of joints. Herbal interventions contribute substantial therapeutic benefits including accessibility, less or no toxicity and affordability. But the major challenge with these natural actives is the need of a tailored approach for treating inflamed tissues by delivering these bioactive agentsat an appropriate dose within the treatment regimen for an extended periodof time. Drug incorporated with wide range of delivery systems such as liposomes, nanoparticles, polymeric micelles, and other nano-vehicles have been developed to achieve this goal. Thus, inclinations of modern treatment are persuaded on the way to herbal therapy or phytomedicines in combination with novel carriers is an alternative approach with less adverse effects. The present review further summarizes the significanceof use of phytocompounds, their target molecules/pathways and, toxicity and challenges associated with phytomolecule-based nanoformulations.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

The Role of Marine n-3 Polyunsaturated Fatty Acids in Inflammatory-Based Disease: The Case of Rheumatoid Arthritis

Inflammation is a conserved process that involves the activation of immune and non-immune cells aimed at protecting the host from bacteria, viruses, toxins and injury. However, unresolved inflammation and the permanent release of pro-inflammatory mediators are responsible for the promotion of a condition called "low-grade systemic chronic inflammation", which is characterized by tissue and organ damage, metabolic changes and an increased susceptibility to non-communicable diseases. Several studies have demonstrated that different dietary components may influence modifiable risk factors for diverse chronic human pathologies. Marine n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), are well-recognized anti-inflammatory and immunomodulatory agents that are able to influence many aspects of the inflammatory process. The aim of this article is to review the recent literature that relates to the modulation of human disease, such as rheumatoid arthritis, by n-3 PUFAs.

Supramolecular Integration of Multifunctional Nanomaterial by Mannose-Decorated Azocalixarene with Ginsenoside Rb1 for Synergistic Therapy of Rheumatoid Arthritis

The complexity and progressive nature of diseases require the exploitation of multifunctional materials. However, introducing a function inevitably increases the complexity of materials, which complicates preparation and decreases reproducibility. Herein, we report a supramolecular integration of multifunctional nanomaterials based on mannose-modified azocalix[4]arene (ManAC4A) and ginsenoside Rb1 (Rb1), which showed advances of simplicity and reproducibility. ManAC4A possesses reactive oxygen species (ROS) scavenging capacity and hypoxia-responsiveness, together with macrophage-targeting and induction functionality. Collectively, the Rb1@ManAC4A assembly simply prepared by two components is integrated with multifunction, including triple targeting (ELVIS targeting, macrophage-targeting, and hypoxia-targeted release) and triple therapy (ROS scavenging, macrophage polarization, and the anti-inflammatory effect of Rb1). The spontaneous assembly and recognition of ManAC4A, with its precise structure and molecular weight, facilitated the simple and straightforward preparation of Rb1@ManAC4A, leading to excellent batch consistency. Progress in simplicity and reproducibility, as directed by this research, will catalyze the clinical translation of multifunctional materials.

Advances in Formulations of Microneedle System for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic joint inflammation, eventually leading to severe disability and premature death. At present, the treatment of RA is mainly to reduce inflammation, swelling, and pain. Commonly used drugs are non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and disease-modifying anti-rheumatic drugs (DMARDs). These drugs lack specificity and require long-term, high-dose administration, which can cause serious adverse effects. In addition, the oral, intravenous, and intra-articular injections will reduce patient compliance, resulting in high cost and low bioavailability. Due to these limitations, microneedles (MNs) have emerged as a new strategy to efficiently localize the drugs in inflamed joints for the treatment of RA. MNs can overcome the cuticle barrier of the skin without stimulating nerves and blood vessels. Which can increase patient compliance, improve bioavailability, and avoid systemic circulation. This review summarizes and evaluates the application of MNs in RA, especially dissolving MNs (DMNs). We encourage the use of MNs to treat RA, by describing the general properties of MNs, materials, preparation technology, drug release mechanism, and advantages. Furthermore, we discussed the biological safety, development prospects, and future challenges of MNs, hoping to provide a new strategy for the treatment of RA.

The long non-coding RNA HOTAIR contributes to joint-specific gene expression in rheumatoid arthritis

Although patients with rheumatoid arthritis (RA) typically exhibit symmetrical joint involvement, some patients develop alternative disease patterns in response to treatment, suggesting that different molecular mechanism may underlie disease progression depending on joint location. Here, we identify joint-specific changes in RA synovium and synovial fibroblasts (SF) between knee and hand joints. We show that the long non-coding RNA HOTAIR, which is only expressed in knee SF, regulates more than 50% of this site-specific gene expression in SF. HOTAIR is downregulated after stimulation with pro-inflammatory cytokines and is expressed at lower levels in knee samples from patients with RA, compared with osteoarthritis. Knockdown of HOTAIR in knee SF increases PI-Akt signalling and IL-6 production, but reduces Wnt signalling. Silencing HOTAIR inhibits the migratory function of SF, decreases SF-mediated osteoclastogenesis, and increases the recruitment of B cells by SF. We propose that HOTAIR is an important epigenetic factor in joint-specific gene expression in RA.

A Peripheral Blood Signature of Increased Th1 and Myeloid Cells Combined with Serum Inflammatory Mediators Is Associated with Response to Abatacept in Rheumatoid Arthritis Patients

Abatacept (CTLA4-Ig)-a monoclonal antibody which restricts T cell activation-is an effective treatment for rheumatoid arthritis (RA). Nevertheless, only 50% of RA patients attain clinical responses, while predictors of response are rather limited. Herein, we aimed to investigate for early biomarkers of response to abatacept, based on a detailed immunological profiling of peripheral blood (PB) cells and serum proteins. We applied flow cytometry and proteomics analysis on PB immune cells and serum respectively, of RA patients starting abatacept as the first biologic agent. After 6 months of treatment, 34.5% of patients attained response. At baseline, Th1 and FoxP3+ T cell populations were positively correlated with tender joint counts (p-value = 0.047 and p-value = 0.022, respectively). Upon treatment, CTLA4-Ig effectively reduced the percentages of Th1 and Th17 only in responders (p-value = 0.0277 and p-value = 0.0042, respectively). Notably, baseline levels of Th1 and myeloid cell populations were significantly increased in PB of responders compared to non-responders (p-value = 0.009 and p-value = 0.03, respectively). Proteomics analysis revealed that several inflammatory mediators were present in serum of responders before therapy initiation and strikingly 10 amongst 303 serum proteins were associated with clinical responses. Finally, a composite index based on selected baseline cellular and proteomics' analysis could predict response to abatacept with a high sensitivity (90%) and specificity (88.24%).

Exploring the pharmacological mechanisms and key active ingredients of total flavonoids from Lamiophlomis rotata (Benth.) Kudo against rheumatoid arthritis based on multi-technology integrated network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Lamiophlomis rotata (Benth.) Kudo (LR, Lamiaceae) is a traditional Tibetan medicinal material in China. Tibetan medicine classic and research report suggested that LR could be used to cure rheumatoid arthritis (RA). However, the anti-RA active ingredients and pharmacological mechanisms of LR have not been elucidated.

AIM OF THE STUDY

To explore the mechanisms and key active ingredients of total flavonoids from LR (TFLR) against RA.

MATERIALS AND METHODS

First, the mechanisms of TFLR against RA were investigated on collagen-induced arthritis (CIA) rat model by analyzing paw appearance, paw swelling, arthritis score, spleen index, thymus index, inflammatory cytokine (TNF-α, IL-1β, IL-6 and IL-17) levels in serum, histopathology of ankle joint and synovium from knee joint (hematoxylin-eosin, safranin O-fast green and DAB-TUNEL staining), and apoptosis-related protein (PI3K, Akt1, p-Akt, Bad, p-Bad, Bcl-xL and Bcl-2) levels in the synovium of ankle joints (Western blot). Then, the crucially active ingredients of TFLR against RA were explored by network pharmacology, ingredient analysis, in vitro metabolism and TNF-α-induced human RA synovial fibroblast MH7A proliferation assays. Network pharmacology was applied to predict the key active ingredients of TFLR against RA. The ingredient analysis and in vitro metabolism of TFLR were performed on HPLC, and MH7A proliferation assay were applied to evaluate the predicted results of network pharmacology.

RESULTS

TFLR shown excellently anti-RA effect by reducing paw swelling, arthritis score, spleen index, thymus index and inflammatory cytokine (IL-1β, IL-6 and IL-17) levels, and improving the histopathological changes of ankle joint and synovium from knee joint in CIA rats. Results of Western blot indicated that TFLR reversed the changes of PI3K, p-Akt, p-Bad, Bcl-xL and Bcl-2 levels in the ankle joint synovium of CIA rats. Results of network pharmacology exhibited that luteolin was identified as the pivotal active ingredient of TFLR against RA. The ingredient analysis of TFLR indicated that the main ingredient in TFLR was luteoloside. The in vitro metabolism study of TFLR suggested that luteoloside could be converted to luteolin in artificial gastric juice and intestinal juice. Results of MH7A proliferation assay showed that there was no significant difference between TFLR and equal luteoloside on the viability of MH7A cells, indicating that luteoloside was the key active ingredient of TFLR against RA. Additionally, the luteolin (same mol as luteoloside) showed better inhibitory effect on the viability of MH7A cells than luteoloside.

CONCLUSION

TFLR showed anti-RA effect, and the mechanism was related to promoting synovial cell apoptosis mediated by PI3K/Akt/Bad pathway. Meanwhile, this work indicated that luteoloside was the key active ingredient of TFLR against RA. This work lays a foundation for providing TFLR product with clear mechanism and stable quality to treat RA.

Could endothelial progenitor cells complement the diagnosis of inflammatory arthritis? A systematic review and meta-analysis

The objective of this meta-analysis was to systematically review existing evidence and evaluate variations in levels of circulating endothelial progenitor cells (EPCs) among individuals with psoriatic arthritis (PsA), juvenile idiopathic arthritis (JIA), and rheumatoid arthritis (RA). Relevant studies were identified through database searches, and 20 records were enrolled. We used the fixed-effect model or random-effect model to estimate the pooled standardized mean difference (SMD) with 95% confidence intervals (CIs) in circulating EPC levels between inflammatory arthritis patients and controls. The results showed that circulating EPC levels differed among subtypes of inflammatory arthritis, with significantly lower levels in patients with RA (SMD = -0.848, 95% CI = -1.474 to -0.221, p = 0.008) and PsA (SMD = -0.791, 95% CI = -1.136 to -0.446, p < 0.001). However, no statistically significant difference was found in circulating EPC levels between patients with JIA and controls (SMD = -1.160, 95% CI = -2.578 to 0.259, p = 0.109). Subgroup analyses suggested that in patients with RA, circulating EPC levels were influenced by age, disease activity, and duration. Although many studies have investigated circulating EPC levels in patients with inflammatory arthritis, the results have been inconsistent. This meta-analysis offers a comprehensive overview of the existing evidence and emphasizes the association between levels of circulating EPCs and various types of arthritis. However, further research is needed to determine the specific mechanisms underlying the observed differences in EPC levels in different types of arthritis and to establish the clinical utility of this biomarker.

Relationship of Complete Blood Count Derived Biomarkers With Methotrexate Resistance

Background Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and joint damage. Among the therapeutic agents, methotrexate remains a cornerstone of initial treatment. Complete blood count (CBC)-derived biomarkers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), and systemic immune response index (SIRI) have been extensively studied in various diseases. Still, their specific role in RA patients undergoing methotrexate treatment has not been investigated. Objective This study aimed to investigate the relationship of CBC-derived biomarkers with methotrexate resistance in newly diagnosed rheumatoid arthritis patients. Methods We performed a comprehensive analysis of 54 RA patients, divided into methotrexate-resistant (MTXR) and methotrexate-sensitive (MTXS) groups. Analysis of variance (ANOVA) was used to assess differences in hematological biomarkers between groups. Standard t-tests were used to compare specific biomarkers between the MTXR and MTXS groups. The chi-squared test was used to compare categorical variables between groups. Pearson's correlation test was also used to examine correlations between these biomarkers and Disease Activity Score 28 (DAS28) in both groups. Receiver operating characteristic (ROC) curve analysis was performed for each biomarker to determine predictive ability. Results A statistically increased PLR ratio was observed in the MTXR group compared to the MTXS group. Significant correlations between DAS28 and NLR, PLR, SII, and SIRI were observed in the MTXR group. In contrast, these correlations were absent in the MTXS group. In addition to PLR, DAS28 and ESR were significantly higher in the MTXR group than in the MTXS group. None of these biomarkers showed prognostic value for methotrexate treatment outcomes. Conclusion PLR could be used as a biomarker for resistance to methotrexate treatment in a specific RA patient population. Increased PLR and ESR, together with higher DAS28, might be associated with a more pronounced inflammatory state in MTXR patients.

Understanding the roles of the microbiome in autoimmune rheumatic diseases

The gut microbiome represents a potential promising therapeutic target for autoimmune diseases. This review summarizes the current knowledge on the links between the gut microbiome and several autoimmune rheumatic diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) spondyloarthropathies (SpA), Sjogren's syndrome (SS), and systemic sclerosis (SSc). Evidence from studies of RA and SLE patients suggests that alterations in the gut microbiome composition and function contribute to disease development and progression through increased gut permeability, with microbes and microbial metabolites driving an excessive systemic activation of the immune system. Also, there is growing evidence that gut dysbiosis and subsequent immune cell activation may contribute to disease pathogenesis in SpA and SS. For SSc, there are fewer, but these are still informative, reports on alterations in the gut microbiome. In general, the complex interplay between the microbiome and the immune system is still not fully understood. Here we discuss the current knowledge of the link between the gut microbiome and autoimmune rheumatic diseases, highlighting potentially fertile areas for future research and make considerations on the potential benefits of strategies that restore gut microbiome homeostasis.

Oridonin Promotes Apoptosis in Rheumatoid Arthritis Fibroblast-like Synoviocytes Through PERK/eIF2α/CHOP of Endoplasmic Reticulum Stress Pathway

Oridonin (ORI), derived from Chinese herbs Rabdosia rubescens, has anti-inflammatory, proapoptotic, anticancer effects. Previous studies have found that ORI induces apoptosis in rheumatoid arthritis fibroblast synovial cells (RA-FLSs), but this mechanism is not clear. We will investigate the apoptosis mechanism of ORI on RA-FLSs. RA-FLSs were treated with various concentrations of ORI (0, 5, 10, 15, 20, 25, and 30 μM) for 24 h. CCK8, LDH, and hochest/PI assay determined the viability, cytotoxicity, and death of ORI on RA-FLSs. The endoplasmic reticulum probe was used to observe structural changes of endoplasmic reticulum in RA-FLSs. RNA expression was detected with RNA sequencing analysis and quantitative real-time PCR. The PERK/eIF2α/CHOP pathway protein of the endoplasmic reticulum was verified with Western Blot. Our results show that ORI induced the apoptosis of RA-FLSs from CCK8, LDH, and Hochest/PI. The endoplasmic reticulum distribution was altered in RA-FLSs after being treated with ORI. Bioinformatics analysis of RNA sequencing data found that 1453 genes were elevated. The PERK/eIF2α/CHOP pathway of the endoplasmic reticulum was regulated from the Gene ontology and KEGG analysis. The results of quantitative real-time PCR and Western blot analysis verified the regulation of PERK/eIF2α/CHOP pathway in RA-FLSs. Our data imply that the endoplasmic reticulum's PERK/eIF2α/CHOP signaling pathway is certainly implicated in the induction of RA-FLS apoptosis by ORI. This study has important implications for the pharmacological effects of ORI and the treatment of RA.

Pathophysiology to advanced intra-articular drug delivery strategies: Unravelling rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most prevalent life-long autoimmune diseases with an unknown genesis. It primarily causes chronic inflammation, pain, and synovial joint-associated cartilage and bone degradation. Unfortunately, limited information is available regarding the etiology and pathogenesis of this chronic joint disorder. In the last few decades, an improved understanding of RA pathophysiology about key immune cells, antibodies, and cytokines has inspired the development of several anti-rheumatic drugs and biopharmaceuticals to act on RA-affected joints. However, life-long frequent systemic high doses of commercially available drugs are currently a limiting factor in the efficient management of RA. To address this issue, various single and double-barrier intra-articular drug delivery systems (IA-DDSs) such as nanocarriers, microparticles, hydrogels, and particles-hybrid hydrogel composite have been developed which can exclusively target the RA-affected joint cavity and release the precisely controlled therapeutic drug concentration for prolonged time whilst avoiding the systemic toxicity. This review provides a comprehensive overview of the pathogenesis of RA and discusses the rational design and development of biomaterials-based novel IA-DDs, ranging from conventional to advanced systems, for improved treatment of RA. Therefore, this review aims to unravel the pathophysiology of rheumatoid arthritis and explore cutting-edge IA-DD strategies exploiting biomaterials. It offers researchers a consolidated and up-to-date resource platform to analyze existing knowledge, identify research gaps, and contribute to the scientific literature.

Quercetin is a Potential Therapy for Rheumatoid Arthritis via Targeting Caspase-8 Through Ferroptosis and Pyroptosis

Background

Rheumatoid arthritis (RA) is one of the most common chronic inflammatory autoimmune diseases. However, the underlying molecular mechanisms of its pathogenesis are unknown. This study aimed to identify the common biomarkers of ferroptosis and pyroptosis in RA and screen potential drugs.

Methods

The RA-related differentially expressed genes (DEGs) in GSE55235 were screened by R software and intersected with ferroptosis and pyroptosis gene libraries to obtain differentially expressed ferroptosis-related genes (DEFRGs) and differentially expressed pyroptosis-related genes (DEPRGs). We performed Gene Ontology (GO), Kyoto Encyclopedia of the Genome (KEGG), ClueGO, and Protein-Protein Interaction (PPI) analysis for DEFRGs and DEPRGs and validated them by machine learning. The microRNA/transcription factor (TF)-hub genes regulatory network was further constructed. The key gene was validated using the GSE77298 validation set, cellular validation was performed in in vitro experiments, and immune infiltration analysis was performed using CIBERSORT. Network pharmacology was used to find key gene-targeting drugs, followed by molecular docking and molecular dynamics simulations to analyze the binding stability between small-molecule drugs and large-molecule proteins.

Results

Three hub genes (CASP8, PTGS2, and JUN) were screened via bioinformatics, and the key gene (CASP8) was validated and obtained through the validation set, and the diagnostic efficacy was verified to be excellent through the receiver operating characteristic (ROC) curves. The ferroptosis and pyroptosis phenotypes were constructed by fibroblast-like synoviocytes (FLS), and caspase-8 was detected and validated as a common biomarker for ferroptosis and pyroptosis in RA, and quercetin can reduce caspase-8 levels. Quercetin was found to be a potential target drug for caspase-8 by network pharmacology, and the stability of their binding was further verified using molecular docking and molecular dynamics simulations.

Conclusion

Caspase-8 is an important biomarker for ferroptosis and pyroptosis in RA, and quercetin is a potential therapy for RA via targeting caspase-8 through ferroptosis and pyroptosis.

Wnt5a: A promising therapeutic target for inflammation, especially rheumatoid arthritis

BACKGROUND

Wnt5a is a member of the Wnt protein family, which acts on classical or multiple non-classical Wnt signaling pathways by binding to different receptors. The expression regulation and signal transduction of Wnt5a is closely related to the inflammatory response. Abnormal activation of Wnt5a signaling is an important part of inflammation and rheumatoid arthritis (RA).

OBJECTIVES

This paper mainly focuses on Wnt5a protein and its mediated signaling pathway, summarizes the latest research progress of Wnt5a in the pathological process of inflammation and RA, and looks forward to the main directions of Wnt5a in RA research, aiming to provide a theoretical basis for the prevention and treatment of RA diseases by targeting Wnt5a.

RESULTS

Wnt5a is highly expressed in activated blood vessels, histocytes and synoviocytes in inflammatory diseases such as sepsis, sepsis, atherosclerosis and rheumatoid arthritis. It mediates the production of pro-inflammatory cytokines and chemokines, regulates the migration and recruitment of various immune effector cells, and thus participates in the inflammatory response. Wnt5a plays a pathological role in synovial inflammation and bone destruction of RA, and may be an important clinical therapeutic target for RA.

CONCLUSION

Wnt5a is involved in the pathological process of inflammation and interacts with inflammatory factors. Wnt5a may be a new target for regulating the progression of RA disease and intervening therapy because of its multi-modal effects on the etiology of RA, especially as a regulator of osteoclast activity and inflammation.

The effect of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis: A double-blind, placebo, controlled randomized clinical trial

Propolis has gained popularity in recent years because of its beneficial properties, which make it a possible preventative and therapeutic agent as well as a valuable food and cosmetic ingredient. The objective of this study was to evaluate the effects of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis. This randomized, double-blind, placebo-controlled clinical trial was performed among 48 patients diagnosed with rheumatoid arthritis. Subjects were randomly assigned to placebo and intervention groups, supplemented with 1000 mg/day of propolis for 12 weeks. Cardiovascular risk factors including, high-sensitivity C-reactive protein (hs-CRP), monocyte chemoattractant protein (MCP-1), Nitric oxide, blood pressure, and lipid profile were assessed pre-and post-intervention. The atherogenic index of plasma value, as well as total cholesterol/high-density lipoprotein cholesterol (HDL-C), triglyceride/HDL-C, and non-HDL-C/HDL-C ratios, were significantly reduced in the intervention group, compared with the placebo group post-intervention (p < 0.05). Moreover, there was a significant reduction in the serum level of hs-CRP in the intervention group when compared with the placebo group (p = 0.001). Furthermore, propolis supplementation could marginally reduce MCP-1 (p = 0.051). These data indicate that propolis supplementation may be a promising treatment strategy for cardiovascular complications among rheumatoid arthritis patients.

Gaafar AR, Nafidi HA, Bourhia M. Mechanistic Evaluation of Antiarthritic Effects of Citronellol in CFA-Induced Arthritic Rats

Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic inflammation, joint tissue damage, pain, and synovitis. It leads to deformity of joints, disability, and even premature death. Markers of inflammation are highly expressed in synovium fluid and serum of arthritic patients and play an important role in the pathophysiology of RA. These transcription factors promote the fabrication of type I interferons and inflammatory cytokines. In RA, degradation of synovial cartilage and bone results from stimulation of proinflammatory cytokines. Citronellol (Ct), a monoterpene alcohol, is found in citrus fruits and essential oils of many aromatic plants. It possesses numerous pharmacological properties such as antioxidant activity and potential antinociceptive and anti-inflammatory effects. Keeping in view the significant anti-inflammatory role of Ct, a trial of 28 days was conducted. Ct was administered orally at three different doses (25, 50, and 100) mg/kg in Freund's adjuvant-induced arthritic rats, and the results were compared with piroxicam, chosen as the standard drug. The antiarthritic activity of the compound was evaluated through measurements of arthritic scoring and plethysmometry before and after treatment. The blood biochemical and hematological parameters and histopathological analyses were performed. Additionally, qPCR was conducted to analyze the mRNA expression levels of TNF-α, IL-1β, NF-κB, MMP3, IL-6, and IL-4 in the blood. ELISA was performed to evaluate the levels of PGE2. The results demonstrated that Ct showed significant results at all doses, but the highest dose proved to be most significant in terms of decreasing arthritic scoring and paw edema, indicating the antiarthritic potential of Ct. Furthermore, the compound was found to downregulate all the proinflammatory cytokines (TNF-α, IL-1β, NF-κB, MMP3, and IL-6) and upregulate the anti-inflammatory cytokine (IL-4). The levels of PGE2 were also reduced which further supported the antiarthritic effects of Ct and validated it as a potential antiarthritic candidate.

Design, synthesis and evaluation of ursodeoxycholic acid-cinnamic acid hybrids as potential anti-inflammatory agents by inhibiting Akt/NF-κB and MAPK signaling pathways

A series of ursodeoxycholic acid (UDCA)-cinnamic acid hybrids were designed and synthesized. The anti-inflammatory activity of these derivatives was screened through evaluating their inhibitory effects of LPS-induced nitric oxide production in RAW264.7 macrophages. The preliminary structure-activity relationship was concluded. Among them, 2m showed the best inhibitory activity against NO (IC50 = 7.70 μM) with no significant toxicity. Further study revealed that 2m significantly decreased the levels of TNF-α, IL-1β, IL-6 and PGE2, down-regulated the expression of iNOS and COX-2. Preliminary mechanism study indicated that the anti-inflammatory activity of 2m was related to the inhibition of the Akt/NF-κB and MAPK signaling pathway. Furthermore, 2m reduced inflammation by a mouse model of LPS-induced inflammatory disease in vivo. In brief, our findings indicated that 2m might serve as a new lead compound for further development of anti-inflammatory agents.

Rspo2 exacerbates rheumatoid arthritis by targeting aggressive phenotype of fibroblast-like synoviocytes and disrupting chondrocyte homeostasis via Wnt/β-catenin pathway

BACKGROUND

The aggressive phenotype of fibroblast-like synoviocytes (FLS) has been identified as a contributing factor to the exacerbation of rheumatoid arthritis (RA) through the promotion of synovitis and cartilage damage. Regrettably, there is currently no effective therapeutic intervention available to address this issue. Recent research has shed light on the crucial regulatory role of R-spondin-2 (Rspo2) in cellular proliferation, cartilage degradation, and tumorigenesis. However, the specific impact of Rspo2 on RA remains poorly understood. We aim to investigate the function and mechanism of Rspo2 in regulating the aggressive phenotype of FLS and maintaining chondrocyte homeostasis in the context of RA.

METHODS

The expression of Rspo2 in knee joint synovium and cartilage were detected in RA mice with antigen-induced arthritis (AIA) and RA patients. Recombinant mouse Rspo2 (rmRspo2), Rspo2 neutralizing antibody (Rspo2-NAb), and recombinant mouse DKK1 (rmDKK1, a potent inhibitor of Wnt signaling pathway) were used to explore the role and mechanism of Rspo2 in the progression of RA, specifically in relation to the aggressive phenotype of FLS and chondrocyte homeostasis, both in vivo and in vitro.

RESULTS

We indicated that Rspo2 expression was upregulated both in synovium and articular cartilage as RA progressed in RA mice and RA patients. Increased Rspo2 upregulated the expression of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), as the ligand for Rspo2, and β-catenin in FLS and chondrocytes. Subsequent investigations revealed that intra-articular administration of rmRspo2 caused striking progressive synovitis and articular cartilage destruction to exacerbate RA progress in mice. Conversely, neutralization of Rspo2 or inhibition of the Wnt/β-catenin pathway effectively alleviated experimental RA development. Moreover, Rspo2 facilitated FLS aggressive phenotype and disrupted chondrocyte homeostasis primarily through activating Wnt/β-catenin pathway, which were effectively alleviated by Rspo2-NAb or rmDKK1.

CONCLUSIONS

Our data confirmed a critical role of Rspo2 in enhancing the aggressive phenotype of FLS and disrupting chondrocyte homeostasis through the Wnt/β-catenin pathway in the context of RA. Furthermore, the results indicated that intra-articular administration of Rspo2 neutralizing antibody or recombinant DKK1 might represent a promising therapeutic strategy for the treatment of RA.

A Targeted Exosome Therapeutic Confers Both CfDNA Scavenging and Macrophage Polarization for Ameliorating Rheumatoid Arthritis

Only a minority of rheumatoid arthritis (RA) patients achieve disease remission, so the exploration of additional pathogenic factors and the development of new therapeutics are needed. Here, strong correlations among the cell-free DNA (cfDNA) level and the inflammatory response in clinical synovial fluid samples and RA disease activity are discovered. The important role of cfDNA in disease development in a collagen-induced arthritis (CIA) murine model is also demonstrated. Building on these findings, a novel therapeutic based on anti-inflammatory (M2) macrophage-derived exosomes as chassis, that are modified with both oligolysine and matrix metalloproteinase (MMP)-cleavable polyethylene glycol (PEG) on the membrane, is developed. After intravenous injection, PEG-enabled prolonged circulation and C─C motif chemokine ligand-directed accumulation together result in enrichment at inflamed joints. Following subsequent MMP cleavage, the positively charged oligolysine is exposed for cfDNA scavenging, while exosomes induce M2 polarization. By using a classical CIA murine model and a newly established CIA canine model, it is demonstrated that the rationally designed exosome therapeutic substantially suppresses inflammation in joints and provides strong chondroprotection and osteoprotection, revealing its potential for effective CIA amelioration.

Knowledge mapping of COVID-19 and autoimmune diseases: a visual and bibliometric analysis

BACKGROUND

Many studies have shown an association between COVID-19 and autoimmune diseases (ADs). Studies on COVID-19 and ADs have also increased significantly, but there is no bibliometric analysis to summarize the association between COVID-19 and ADs. The purpose of this study was to perform a bibliometric and visual analysis of published studies related to COVID-19 and ADs.

METHODS

Based on the Web of Science Core Collection SCI-Expanded database, we utilize Excel 2019 and visualization analysis tools Co-Occurrence13.2 (COOC13.2), VOSviewer, CiteSpace, and HistCite for analysis.

RESULTS

A total of 1736 related kinds of papers were included, and the number of papers presented an overall increasing trend. The country/region with the most publications is the USA, the institution is the Harvard Medical School, the author is Yehuda Shoenfeld from Israel, and the journal is Frontiers in Immunology. Research hotspots include immune responses (such as cytokines storm), multisystem ADs (such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis), treatment modalities (such as hydroxychloroquine, rituximab), vaccination and autoimmune mechanisms (such as autoantibodies, molecular mimicry). The future research direction may be the mechanisms and treatment ideas of the association between ADs and COVID-19 (such as NF-κB, hyperinflammation, antiphospholipid antibodies, neutrophil extracellular traps, granulocyte-macrophage colony-stimulating factor), other cross-diseases of COVID-19 and ADs (such as inflammatory bowel disease, chronic mucocutaneous candidiasis, acute respiratory distress syndrome).

CONCLUSION

The growth rate of publications regarding ADs and COVID-19 has risen sharply. Our research results can help researchers grasp the current status of ADs and COVID-19 research and find new research directions in the future.

A newly developed PLD1 inhibitor ameliorates rheumatoid arthritis by regulating pathogenic T and B cells and inhibiting osteoclast differentiation

Phospholipase D1 (PLD1), which catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid and choline, plays multiple roles in inflammation. We investigated the therapeutic effects of the newly developed PLD1 inhibitors A2998, A3000, and A3773 in vitro and in vivo rheumatoid arthritis (RA) model. A3373 reduced the levels of LPS-induced TNF-α, IL-6, and IgG in murine splenocytes in vitro. A3373 also decreased the levels of IFN-γ and IL-17 and the frequencies of Th1, Th17 cells and germinal-center B cells, in splenocytes in vitro. A3373 ameliorated the severity of collagen-induced arthritis (CIA) and suppressed infiltration of inflammatory cells into the joint tissues of mice with CIA compared with vehicle-treated mice. Moreover, A3373 prevented systemic bone demineralization in mice with CIA and suppressed osteoclast differentiation and the mRNA levels of osteoclastogenesis markers in vitro. These results suggest that A3373 has therapeutic potential for RA.

Mechanistic prospective and pharmacological attributes of quercetin in attenuation of different types of arthritis

Arthritis is a frequent autoimmune disease with undefined etiology and pathogenesis. Scientific community constantly fascinating quercetin (QUR), as it is the best-known flavonoid among others for curative and preventive properties against a wide range of diseases. Due to its multifaceted activities, the implementation of QUR against various types of arthritis namely, rheumatoid arthritis (RA), osteoarthritis (OA), gouty arthritis (GA) and psoriotic arthritis (PsA) has greatly increased in recent years. Many research evidenced that QUR regulates a wide range of pathways for instance NF-κB, MAK, Wnt/β-catenine, Notch, etc., that are majorly associated with the inflammatory mechanisms. Besides, the bioavailability of QUR is a major constrain to its therapeutic potential, and drug delivery techniques have experienced significant development to overcome the problem of its limited application. Hence, this review compiled the cutting-edge experiments on versatile effects of QUR on inflammatory diseases like RA, OA, GA and PsA, sources and bioavailability, therapeutic challenges, pharmacokinetics, clinical studies as well as toxicological impacts. The use of QUR in a health context would offer a tearing and potential therapeutic method, supporting the advancement of public health, particularly, of arthritic patients worldwide.

Xuelian injection ameliorates complete Freund's adjuvant-induced acute arthritis in rats via inhibiting TLR4 signaling

Background

Xuelian injection (XI), a classic preparation extracted from Saussureae Involucratae Herba, has been clinically used to manage rheumatoid arthritis (RA) for nearly twenty years in China. However, the underlying anti-RA mechanism of XI remains unclear. In this study, complete Freund's adjuvant (CFA)-induced acute arthritic model was used to examine the anti-RA effects of XI in vivo. The molecular mechanisms of this action were further investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.

Methods

XI and XI freeze dried powder were characterized by UPLC analysis. CD68 and TLR4 expression in the ankle joints was measured by immunohistochemistry. The secretion of inflammatory mediators was detected by ELISA. The expression levels of TLR4 involved components were measured by Western blotting. The localization of transcription factors was measured by immunofluorescence assay.

Results

XI treatment ameliorated arthritic symptoms induced by CFA in the ankle joints of rats. The serum levels of inflammatory mediators, including TNF-α, MCP-1, and Rantes were decreased by XI treatment. The elevation of CD68 and TLR4 levels in ankle joints caused by CFA was suppressed by XI treatment. Moreover, XI treatment inhibited the secretion of nitric oxide and prostaglandin E2 in LPS-treated RAW264.7 macrophages. The expression of their enzymes iNOS and COX-2 was also decreased after XI treatment. The production of inflammatory mediators, including TNF-α, IL-6, IL-1β, MCP-1, MIP-1α, and Rantes was reduced by XI treatment in LPS-stimulated RAW264.7 cells. The phosphorylation of p38, JNK, ERK, TBK1, IKKα/β, IκB, p65, c-Jun, and IRF3 was reduced after XI treatment. Additionally, the expression levels of nuclear proteins of p65, c-Jun, and IRF3 were inhibited by XI treatment.

Conclusions

Taken together, XI possesses potential anti-RA effect and the underlying mechanism may be closely associated with the inhibition of TLR4 signaling. Our findings provide further pharmacological justifications for the clinical use of XI in RA treatment.

Arecoline hydrobromide suppresses PI3K/AKT pathway in rheumatoid arthritis synovial fibroblasts and relieves collagen-induced arthritis in mice

OBJECTIVE

This study investigated the effectiveness of arecoline hydrobromide (AH) on the functions of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) and collagen-induced arthritis (CIA) mice.

METHODS

Immunofluorescence was used to identify RA-FLSs. Cell Counting Kit-8 (CCK-8) was used to determine the viability of RA-FLSs and the half maximal inhibitory concentration (IC50) of AH. The 5-ethynyl-2'-deoxyuridine (EdU) assay was used to detect DNA replication in RA-FLSs. Cell cycle and apoptosis were examined by flow cytometry. Migration and invasion, as well as wound healing assays, were employed to determine cell migration and invasion ability. Proteins and mRNA expression levels were investigated using Western blot, quantitative real-time PCR (RT-qPCR), and immunofluorescence. The CIA mice model was used to assess the effect of AH in vivo. RNA-sequencing (RNA-seq) was used to find the potential signaling pathways of AH against RA, and Western blot was used to verify the key signaling pathway of AH on RA-FLSs. Network pharmacology and molecular docking were used to predict drug targets.

RESULTS

AH inhibited the proliferation and DNA replication of RA-FLSs, promoted cell cycle arrest by reducing the levels of cyclin-dependent kinase 1 (CDK1), cyclin A2, and cyclin B1, promoted apoptosis by suppressing B-cell lymphoma-2 (Bcl-2) expression, and suppressed migration and invasion by inhibiting vimentin expression in RA-FLSs. AH was also effective in relieving arthritis in vivo. RNA sequencing analyses suggested that AH inhibited the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway in RA-FLSs, which was also confirmed in Western blot analysis. Furthermore, network pharmacology and molecular docking suggested that F2, MAPK14, SRC, AKT1, and CTSK might be the direct targets of AH.

CONCLUSION

AH can modulate the pathological process of RA-FLSs by blocking the PI3K/AKT pathway and relieve CIA in mice, making it a potential new small molecule candidate.

Transport by circulating myeloid cells drives liposomal accumulation in inflamed synovium

The therapeutic potential of liposomes to deliver drugs into inflamed tissue is well documented. Liposomes are believed to largely transport drugs into inflamed joints by selective extravasation through endothelial gaps at the inflammatory sites, known as the enhanced permeation and retention effect. However, the potential of blood-circulating myeloid cells for the uptake and delivery of liposomes has been largely overlooked. Here we show that myeloid cells can transport liposomes to inflammatory sites in a collagen-induced arthritis model. It is shown that the selective depletion of the circulating myeloid cells reduces the accumulation of liposomes up to 50-60%, suggesting that myeloid-cell-mediated transport accounts for more than half of liposomal accumulation in inflamed regions. Although it is widely believed that PEGylation inhibits premature liposome clearance by the mononuclear phagocytic system, our data show that the long blood circulation times of PEGylated liposomes rather favours uptake by myeloid cells. This challenges the prevailing theory that synovial liposomal accumulation is primarily due to the enhanced permeation and retention effect and highlights the potential for other pathways of delivery in inflammatory diseases.

Overcoming delivery barriers for RNA therapeutics in the treatment of rheumatoid arthritis

RNA therapeutics can manipulate gene expression or protein production, making them suitable for treating a wide range of diseases. Theoretically, any disease that has a definite biological target would probably find feasible therapeutic approach from RNA-based therapeutics. Numerous clinical trials using RNA therapeutics fighting against cancer, infectious diseases or inherited diseases have been reported and achieved desirable therapeutic efficacy. So far, encouraging findings from various animal experimental studies have also confirmed the great potential of RNA-based therapies in the treatment of rheumatic arthritis (RA). However, the in vivo multiple physiological barriers still seriously compromise the therapeutic efficacy of RNA drugs. Thus, safe and effective delivery strategies for RNA therapeutics are quite essential for their further and wide application in RA therapy. In this review, we will discuss the recent progress achieved using RNA-based therapeutics and focus on delivery strategies that can overcome the in vivo delivery barriers in RA treatment. Furthermore, discussion about the existing problems in current RNA delivery systems for RA therapy has been also included here.

Efficacy and safety of different Janus kinase inhibitors combined with methotrexate for the treatment of rheumatoid arthritis: a single-center randomized trial

OBJECTIVE

To compare the efficacy and safety between baricitinib (BARI) and tofacitinib (TOFA) for the treatment of the rheumatoid arthritis (RA) patients receiving methotrexate (MTX) in clinical practice.

METHODS

This retrospective study recruited 179 RA patients treated with BARI (2-4 mg/d) or TOFA (10 mg/d) at The First Affiliated Hospital of Guangxi Medical University from September 2019 to January 2022. The rate of low disease activity (LDA) was used as the primary end point. Secondary end points included the Disease Activity Scale-28 (DAS-28)-C-reactive protein (CRP); the rate of DAS28-CRP remission; visual analogue scale (VAS) for pain, swollen joint, and tender joint counts; and adverse events at the 6-month follow-up. Several factors affecting LDA achievement were also analyzed.

RESULTS

Seventy-four patients were treated with BARI and 105 were treated with TOFA, including 83.24% females, with a median (IQR) age of 56.0 (53.0-56.0) years old and disease duration of 12.0 (6.0-12.0) months. There was no difference of the rate of LDA between the BARI and TOFA treatment groups. All disease indices in the two groups were significantly improved, including a significantly lower VAS in the BARI group (P < 0.05), reflecting the drug efficacy after 1 and 6 months of treatment. The incidence of adverse reactions was similar in these two groups.

CONCLUSION

The treatment efficacy and safety of BARI and TOFA in the RA patients were similar, but BARI was more effective in pain relief than TOFA. An older baseline age was more likely to achieve LDA in the BARI group, while a low baseline erythrocyte sedimentation rate (ESR) was more likely to achieve LDA in the TOFA group.

Effect of Immunosuppressive or Immunomodulatory Agents on Severe COVID-19 Outcomes: A Population-Based Cohort Study

OBJECTIVE

We estimated the association between immunosuppressive and immunomodulatory agent (IIA) exposure and severe COVID-19 outcomes in a population-based cohort study.

METHODS

Participants were 18 years or older, tested positive for SARS-CoV-2 between February 6, 2020, and August 15, 2021, and were from administrative health data for the entire province of British Columbia, Canada. IIA use within 3 months prior to positive SARS-CoV-2 test included conventional disease-modifying antirheumatic drugs (antimalarials, methotrexate, leflunomide, sulfasalazine, individually), immunosuppressants (azathioprine, mycophenolate mofetil/mycophenolate sodium [MMF], cyclophosphamide, cyclosporine, individually and collectively), tumor necrosis factor inhibitor (TNFi) biologics (adalimumab, certolizumab, etanercept, golimumab, infliximab, collectively), non-TNFi biologics or targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs) (rituximab separately from abatacept, anakinra, secukinumab, tocilizumab, tofacitinib and ustekinumab collectively), and glucocorticoids. Severe COVID-19 outcomes were hospitalizations for COVID-19, ICU admissions, and deaths within 60 days of a positive test. Exposure score-overlap weighting was used to balance baseline characteristics of participants with IIA use compared with nonuse of that IIA. Logistic regression measured the association between IIA use and severe COVID-19 outcomes.

RESULTS

From 147,301 participants, we identified 515 antimalarial, 573 methotrexate, 72 leflunomide, 180 sulfasalazine, 468 immunosuppressant, 378 TNFi biologic, 49 rituximab, 144 other non-TNFi biologic or tsDMARD, and 1348 glucocorticoid prescriptions. Risk of hospitalizations for COVID-19 was significantly greater for MMF (odds ratio [95% CI]): 2.82 [1.81-4.40], all immunosuppressants: 2.08 [1.51-2.87], and glucocorticoids: 1.63 [1.36-1.96], relative to nonuse. Similar outcomes were seen for ICU admission and MMF: 2.52 [1.34-4.74], immunosuppressants: 2.88 [1.73-4.78], and glucocorticoids: 1.86 [1.37-2.54]. Only glucocorticoids use was associated with a significant increase in 60-day mortality: 1.58 [1.21-2.06]. No other IIAs displayed statistically significant associations with severe COVID-19 outcomes.

CONCLUSION

Current use of MMF and glucocorticoids were associated with an increased risk of severe COVID-19 outcomes compared with nonuse. These results emphasize the variety of circumstances of patients taking IIAs.

Mechanistic target of rapamycin (mTOR): a potential new therapeutic target for rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic synovitis and bone destruction. Proinflammatory cytokines activate pathways of immune-mediated inflammation, which aggravates RA. The mechanistic target of rapamycin (mTOR) signaling pathway associated with RA connects immune and metabolic signals, which regulates immune cell proliferation and differentiation, macrophage polarization and migration, antigen presentation, and synovial cell activation. Therefore, therapy strategies targeting mTOR have become an important direction of current RA treatment research. In the current review, we summarize the biological functions of mTOR, its regulatory effects on inflammation, and the curative effects of mTOR inhibitors in RA, thus providing references for the development of RA therapeutic targets and new drugs.

The Mediterranean diet, and not dietary inflammatory index, is associated with rheumatoid arthritis disease activity, the impact of disease and functional disability

PURPOSE

To assess the relationship between adherence to the Mediterranean Diet (MD) /individual Dietary Inflammatory Index (DII) and disease activity, disease impact, and functional status in Rheumatoid Arthritis (RA) patients.

METHODS

RA patients followed at a hospital in Lisbon, Portugal, were recruited. DII was calculated using dietary intake data collected with a food frequency questionnaire (FFQ). Adherence to the MD was obtained using the 14-item Mediterranean Diet assessment tool. Disease Activity Score of 28 Joints (DAS28) and the DAS28 calculated with C-Reactive Protein (DAS28-CRP) were used to assess disease activity. Impact of disease and functional status were evaluated using the Rheumatoid Arthritis Impact of Disease (RAID) questionnaire and the Health Assessment Questionnaire (HAQ), respectively.

RESULTS

120 patients (73.3% female, 61.8 ± 10.1 years of age) were included. Patients with higher adherence to the MD had significantly lower DAS28-CRP (median 3.27(2.37) vs 2.77(1.49), p = 0.030), RAID (median 5.65(2.38) vs 3.51(4.51), p = 0.032) and HAQ (median 1.00(0.56) vs 0.56(1.03), p = 0.013) scores. Higher adherence to the MD reduced the odds of having a higher DAS28 by 70% (OR = 0.303, 95%CI = (0.261, 0.347), p = 0.003). Lower adherence to MD was associated with higher DAS28-CRP (β = - 0.164, p = 0.001), higher RAID (β = - 0.311, p < 0.0001), and higher HAQ scores (β = - 0.089, p = 0.001), irrespective of age, gender, BMI and pharmacological therapy. Mean DII of our cohort was not significantly different from the Portuguese population (0.00 ± 0.17 vs - 0.10 ± 1.46, p = 0.578). No associations between macronutrient intake or DII and RA outcomes were found.

CONCLUSIONS

Higher adherence to the MD was associated with lower disease activity, lower impact of disease, and lower functional disability in RA patients.

An MMP-2 Responsive Nanotheranostic Probe Enabled Synergistic Therapy of Rheumatoid Arthritis and MR/CT Assessment of Therapeutic Response In Situ

This study reports a facile and green synthesis of a new multifunctional nanotheranostic probe for the synergistic therapy of rheumatoid arthritis (RA) and in situ assessment of therapeutic response. The probe is synthesized through a one-step self-assembly of two exquisitely designed peptide-amphiphilic block copolymers (PEG-DTIPA-KGPLGVRK-MTX and Pal-GGGGHHHHD-TCZ) under mild conditions, requiring minimal energy input. The resultant probe demonstrates excellent biocompatibility, water solubility, and colloidal stability. It exhibits a strong IL-6R targeting ability toward inflamed joints, and releases drugs in an MMP-2-responsive manner. The co-loading of methotrexate(MTX) and tocilizumab (TCZ) into the probe enables synergistic RA therapy with improved efficacy by simultaneously decreasing the activity of adenosine synthetase and interfering with the binding of IL-6 to its receptor. In addition, the resultant probe exhibits a high r1 relaxation rate (7.00 mm-1  s-1 ) and X-ray absorption capability (69.04 Hu mm-1 ), enabling sensitive MR and CT dual-modal imaging for simultaneous evaluation of synovial thickness and bone erosion. Both in vitro experiments using lipopolysaccharide-treated RAW264.7 cells and in vivo experiments using collagen-induced arthritis mice demonstrate the probe's high effectiveness in synergistically inhibiting inflammation. This study provides new insights into RA theranostics, therapeutic monitoring, the design of multifunctional theranostic probes, and beyond.

Recent Advances on Cerium Oxide-Based Biomaterials: Toward the Next Generation of Intelligent Theranostics Platforms

Disease or organ damage due to unhealthy living habits, or accidents, is inevitable. Discovering an efficient strategy to address these problems is urgently needed in the clinic. In recent years, the biological applications of nanotechnology have received extensive attention. Among them, as a widely used rare earth oxide, cerium oxide (CeO2 ) has shown good application prospects in biomedical fields due to its attractive physical and chemical properties. Here, the enzyme-like mechanism of CeO2 is elucidated, and the latest research progress in the biomedical field is reviewed. At the nanoscale, Ce ions in CeO2 can be reversibly converted between +3 and +4. The conversion process is accompanied by the generation and elimination of oxygen vacancies, which give CeO2 the performance of dual redox properties. This property facilitates nano-CeO2 to catalyze the scavenging of excess free radicals in organisms, hence providing a possibility for the treatment of oxidative stress diseases such as diabetic foot, arthritis, degenerative neurological diseases, and cancer. In addition, relying on its excellent catalytic properties, customizable life-signaling factor detectors based on electrochemical techniques are developed. At the end of this review, an outlook on the opportunities and challenges of CeO2 in various fields is provided.

Identification of immunological characteristics and cuproptosis-related molecular clusters in Rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by progressive articular damage, functional loss, and comorbidities. The relationship between cuproptosis, a form of programmed cell death, and RA remains unknown. Therefore, this study aimed to explore cuproptosis-related molecular clusters in RA.

METHODS

Gene expression profiles of GSE93272 were downloaded from the Gene Expression Omnibus to identify the expression profiles of cuproptosis regulators and the immune infiltration characteristics of RA. The molecular clusters of cuproptosis-related genes and the related immune cell infiltration were explored. Cluster-specific differentially expressed genes were identified using the weighted gene co-expression network analysis. Further, an external dataset (GSE15573) was used, and an enzyme-linked immunosorbent assay was performed to validate the predictive efficiency.

RESULTS

Thirteen cuproptosis-related genes and activated immune responses were identified between patients with RA and controls. Immune infiltration revealed significant immunological heterogeneity in the two cuproptosis-related molecular clusters in RA. Functional enrichment indicated that Cluster1 and Cluster2 were predominantly enriched in the toll-like receptor signalling pathway and regulation of autophagy, respectively. Further, the performance of FAM96A and CGRRF1 genes in the external validation dataset was observed to be relatively satisfactory (area under the receiver operating characteristic curve = 0.687 and 0.674, respectively). Based on our serum samples, FAM96A and CGRRF1 both exhibited higher expression levels in patients with RA (p = 0.001; p = 0.000).

CONCLUSIONS

Our study systematically illustrated the involvement of cuproptosis in the progression of RA, and explored the pathogenic mechanisms and novel therapeutic strategies for RA, targeting FAM96A and CGRRF1.

Design and Evaluation of Continentalic Acid Encapsulated Transfersomal Gel and Profiling of its Anti-arthritis Activity

Rheumatoid arthritis restricts the physical ability of patients and increases the disease burden; therefore, research has always been focused on evaluating better therapeutic options. The present research aimed to design Continentalic acid (CA)-loaded transfersomes (CA-TF) embedded in Carbopol gel containing permeation enhancer (PE) for the treatment of rheumatoid arthritis. CA-TF was developed via a modified thin film hydration method and incorporated into Carbopol 934 gel containing Eucalyptus oil (EO) as PE. The fabricated CA-TF showed particle size of < 140 nm with spherical geometry, optimal encapsulation efficiency (EE), and sustained drug release pattern. CA-TF-gel along with PE (CA-TF-PE-gel) showed better ex vivo skin penetration than plain CA gel and CA-TF-gel without PE. In vivo evaluation supported improved therapeutic outcomes of CA-TF-PE-gel in terms of behavioral findings, arthritic index, and histological findings whereas biochemical assays and pro-inflammatory cytokines (TNF-α and IL-1β) showed a significant decrease in their levels. Furthermore, immunohistochemistry assay for Nrf2 and HO-1 signaling pathways showed significant improvement in the expression of the Nrf2, and HO-1 proteins to depict improvement in arthritic condition in the animal model. CA-TF-PE-gel significantly delivered CA to the diseased target site via a topical route with promising therapeutic outcomes displayed in the CFA-induced arthritic model.

The prognostic value of whole-genome DNA methylation in response to Leflunomide in patients with Rheumatoid Arthritis

Objective

Although Leflunomide (LEF) is effective in treating rheumatoid arthritis (RA), there are still a considerable number of patients who respond poorly to LEF treatment. Till date, few LEF efficacy-predicting biomarkers have been identified. Herein, we explored and developed a DNA methylation-based predictive model for LEF-treated RA patient prognosis.

Methods

Two hundred forty-five RA patients were prospectively enrolled from four participating study centers. A whole-genome DNA methylation profiling was conducted to identify LEF-related response signatures via comparison of 40 samples using Illumina 850k methylation arrays. Furthermore, differentially methylated positions (DMPs) were validated in the 245 RA patients using a targeted bisulfite sequencing assay. Lastly, prognostic models were developed, which included clinical characteristics and DMPs scores, for the prediction of LEF treatment response using machine learning algorithms.

Results

We recognized a seven-DMP signature consisting of cg17330251, cg19814518, cg20124410, cg21109666, cg22572476, cg23403192, and cg24432675, which was effective in predicting RA patient's LEF response status. In the five machine learning algorithms, the support vector machine (SVM) algorithm provided the best predictive model, with the largest discriminative ability, accuracy, and stability. Lastly, the AUC of the complex model(the 7-DMP scores with the lymphocyte and the diagnostic age) was higher than the simple model (the seven-DMP signature, AUC:0.74 vs 0.73 in the test set).

Conclusion

In conclusion, we constructed a prognostic model integrating a 7-DMP scores with the clinical patient profile to predict responses to LEF treatment. Our model will be able to effectively guide clinicians in determining whether a patient is LEF treatment sensitive or not.

Computer model of IL-6-dependent rheumatoid arthritis in F759 mice

The interleukin-6 (IL-6) amplifier, which describes the simultaneous activation of signal transducer and activator of transcription 3 (STAT3) and NF-κb nuclear factor kappa B (NF-κB), in synovial fibroblasts causes the infiltration of immune cells into the joints of F759 mice. The result is a disease that resembles human rheumatoid arthritis. However, the kinetics and regulatory mechanisms of how augmented transcriptional activation by STAT3 and NF-κB leads to F759 arthritis is unknown. We here show that the STAT3-NF-κB complex is present in the cytoplasm and nucleus and accumulates around NF-κB binding sites of the IL-6 promoter region and established a computer model that shows IL-6 and IL-17 (interleukin 17) signaling promotes the formation of the STAT3-NF-κB complex followed by its binding on promoter regions of NF-κB target genes to accelerate inflammatory responses, including the production of IL-6, epiregulin, and C-C motif chemokine ligand 2 (CCL2), phenotypes consistent with in vitro experiments. The binding also promoted cell growth in the synovium and the recruitment of T helper 17 (Th17) cells and macrophages in the joints. Anti-IL-6 blocking antibody treatment inhibited inflammatory responses even at the late phase, but anti-IL-17 and anti-TNFα antibodies did not. However, anti-IL-17 antibody at the early phase showed inhibitory effects, suggesting that the IL-6 amplifier is dependent on IL-6 and IL-17 stimulation at the early phase, but only on IL-6 at the late phase. These findings demonstrate the molecular mechanism of F759 arthritis can be recapitulated in silico and identify a possible therapeutic strategy for IL-6 amplifier-dependent chronic inflammatory diseases.

The landscape of pathophysiology guided therapeutic strategies for gout treatment

INTRODUCTION

Gout is a common autoinflammatory disease caused by hyperuricemia with acute and/or chronic inflammation as well as tissue damage. Currently, urate-lowering therapy (ULT) and anti-inflammatory therapy are used as first-line strategies for gout treatment. However, traditional drugs for gout treatment exhibit some unexpected side effects and are not suitable for certain patients due to their comorbidity with other chronic disease.

AREAS COVERED

In this review, we described the pathophysiology of hyperuricemia and monosodium urate (MSU) crystal induced inflammatory response during gout development in depth and comprehensively summarized the advances in the investigation of promising ULT drugs as well as anti-inflammatory drugs that might be safer and more effective for gout treatment.

EXPERT OPINION

New drugs that are developed based on these molecular mechanisms exhibited great efficacy on reduction of disease burden both in vitro and in vivo, implying their potential for clinical application. Moreover, hyperthermia also showed regulation effect on MSU crystals formation and the signaling pathways involved in inflammation.

Targeting Lymph Nodes for Systemic Immunosuppression Using Cell-Free-DNA-Scavenging And cGAS-Inhibiting Nanomedicine-In-Hydrogel for Rheumatoid Arthritis Immunotherapy

Rheumatoid arthritis (RA) is a systemic autoimmune disease with pathogenic inflammation caused partly by excessive cell-free DNA (cfDNA). Specifically, cfDNA is internalized into immune cells, such as macrophages in lymphoid tissues and joints, and activates pattern recognition receptors, including cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS), resulting in overly strong proinflammation. Here, nanomedicine-in-hydrogel (NiH) is reported that co-delivers cGAS inhibitor RU.521 (RU) and cfDNA-scavenging cationic nanoparticles (cNPs) to draining lymph nodes (LNs) for systemic immunosuppression in RA therapy. Upon subcutaneous injection, NiH prolongs LN retention of RU and cNPs, which pharmacologically inhibit cGAS and scavenged cfDNA, respectively, to inhibit proinflammation. NiH elicits systemic immunosuppression, repolarizes macrophages, increases fractions of immunosuppressive cells, and decreases fractions of CD4+ T cells and T helper 17 cells. Such skewed immune milieu allows NiH to significantly inhibit RA progression in collagen-induced arthritis mice. These studies underscore the great potential of NiH for RA immunotherapy.