Gout: a disease involved with complicated immunoinflammatory responses: a narrative review

Traditional herbal medicine: Therapeutic potential in acute gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Acute gouty arthritis (AGA) is characterized by a rapid inflammatory reaction caused by the build-up of monosodium urate (MSU) crystals in the tissues surrounding the joints. This condition often associated with hyperuricemia (HUA), is distinguished by its symptoms of intense pain, active inflammation, and swelling of the joints. Traditional approaches in AGA management often fall short of desired outcomes in clinical settings. However, recent ethnopharmacological investigations have been focusing on the potential of Traditional Herbal Medicine (THM) in various forms, exploring their therapeutic impact and targets in AGA treatment.

AIM OF THE REVIEW

This review briefly summarizes the current potential pharmacological mechanisms of THMs - including active ingredients, extracts, and prescriptions -in the treatment of AGA, and discusses the relevant potential mechanisms and molecular targets in depth. The objective of this study is to offer extensive information and a reference point for the exploration of targeted AGA treatment using THMs.

MATERIALS AND METHODS

This review obtained scientific publications focused on in vitro and in vivo studies of anti-AGA THMs conducted between 2013 and 2023. The literature was collected from various journals and electronic databases, including PubMed, Elsevier, ScienceDirect, Web of Science, and Google Scholar. The retrieval and analysis of relevant articles were guided by keywords such as "acute gouty arthritis and Chinese herbal medicine," "acute gouty arthritis herbal prescription," "acute gouty arthritis and immune cells," "acute gouty arthritis and inflammation," "acute gouty arthritis and NOD-like receptor thermoprotein domain associated protein 3 (NLRP3)," "acute gouty arthritis and miRNA," and "acute gouty arthritis and oxidative stress."

RESULTS

We found that AGA has a large number of therapeutic targets, highlighting the effectiveness the potential of THMs in AGA treatment through in vitro and in vivo studies. THMs and their active ingredients can mitigate AGA symptoms through a variety of therapeutic targets, such as influencing macrophage polarization, neutrophils, T cells, natural killer (NK) cells, and addressing factors like inflammation, NLRP3 inflammasome, signaling pathways, oxidative stress, and miRNA multi-target interactions. The anti-AGA properties of THMs, including their active components and prescriptions, were systematically summarized and categorized based on their respective therapeutic targets.

CONCLUSION

phenolic, flavonoid, terpenoid and alkaloid compounds in THMs are considered the key ingredients to improve AGA. THMs and their active ingredients achieve enhanced efficacy through interactions with multiple targets, of which NLRP3 is a main therapeutic target. Nonetheless, given the intricate composition of traditional Chinese medicine (TCM), additional research is required to unravel the underlying mechanisms and molecular targets through which THMs alleviate AGA.

Single-cell and genome-wide Mendelian randomization identifies causative genes for gout

BACKGROUND

Gout is a prevalent manifestation of metabolic osteoarthritis induced by elevated blood uric acid levels. The purpose of this study was to investigate the mechanisms of gene expression regulation in gout disease and elucidate its pathogenesis.

METHODS

The study integrated gout genome-wide association study (GWAS) data, single-cell transcriptomics (scRNA-seq), expression quantitative trait loci (eQTL), and methylation quantitative trait loci (mQTL) data for analysis, and utilized two-sample Mendelian randomization study to comprehend the causal relationship between proteins and gout.

RESULTS

We identified 17 association signals for gout at unique genetic loci, including four genes related by protein-protein interaction network (PPI) analysis: TRIM46, THBS3, MTX1, and KRTCAP2. Additionally, we discerned 22 methylation sites in relation to gout. The study also found that genes such as TRIM46, MAP3K11, KRTCAP2, and TM7SF2 could potentially elevate the risk of gout. Through a Mendelian randomization (MR) analysis, we identified three proteins causally associated with gout: ADH1B, BMP1, and HIST1H3A.

CONCLUSION

According to our findings, gout is linked with the expression and function of particular genes and proteins. These genes and proteins have the potential to function as novel diagnostic and therapeutic targets for gout. These discoveries shed new light on the pathological mechanisms of gout and clear the way for future research on this condition.

Unveiling potent Schiff base derivatives with selective xanthine oxidase inhibition: In silico and in vitro approach

This research describes the synthesis by an environmentally-friendly method, microwave irradiation, development and analysis of three novel and one previously identified Schiff base derivative as a potential inhibitor of bovine xanthine oxidase (BXO), a key enzyme implicated in the progression of gout. Meticulous experimentation revealed that these compounds (10, 9, 4, and 7) have noteworthy inhibitory effects on BXO, with IC50 values ranging from 149.56 µM to 263.60 µM, indicating their good efficacy compared to that of the standard control. The validation of these results was further enhanced through comprehensive in silico studies, which revealed the pivotal interactions between the inhibitors and the catalytic sites of BXO, with a particular emphasis on the imine group (-C = N-) functionalities. Intriguingly, the compounds exhibiting the highest inhibition rates also showcase advantageous ADMET profiles, alongside encouraging initial assessments via PASS, hinting at their broad-spectrum potential. The implications of these findings are profound, suggesting that these Schiff base derivatives not only offer a new vantage point for the inhibition of BXO but also hold considerable promise as innovative therapeutic agents in the management and treatment of gout, marking a significant leap forward in the quest for more effective gout interventions.

Targeting Neutrophil Extracellular Traps in Gouty Arthritis: Insights into Pathogenesis and Therapeutic Potential

Gouty arthritis (GA) is an immune-mediated disorder characterized by severe inflammation due to the deposition of monosodium urate (MSU) crystals in the joints. The pathophysiological mechanisms of GA are not yet fully understood, and therefore, the identification of effective therapeutic targets is of paramount importance. Neutrophil extracellular traps (NETs), an intricate structure of DNA scaffold, encompassing myeloperoxidase, histones, and elastases - have gained significant attention as a prospective therapeutic target for gouty arthritis, due to their innate antimicrobial and immunomodulatory properties. Hence, exploring the therapeutic potential of NETs in gouty arthritis remains an enticing avenue for further investigation. During the process of gouty arthritis, the formation of NETs triggers the release of inflammatory cytokines, thereby contributing to the inflammatory response, while MSU crystals and cytokines are sequestered and degraded by the aggregation of NETs. Here, we provide a concise summary of the inflammatory processes underlying the initiation and resolution of gouty arthritis mediated by NETs. Furthermore, this review presents an overview of the current pharmacological approaches for treating gouty arthritis and summarizes the potential of natural and synthetic product-based inhibitors that target NET formation as novel therapeutic options, alongside elucidating the intrinsic challenges of these inhibitors in NETs research. Lastly, the limitations of HL-60 cell as a suitable substitute of neutrophils in NETs research are summarized and discussed. Series of recommendations are provided, strategically oriented towards guiding future investigations to effectively address these concerns. These findings will contribute to an enhanced comprehension of the interplay between NETs and GA, facilitating the proposition of innovative therapeutic strategies and novel approaches for the management of GA.

The Impact of Different Intensities of Physical Activity on Serum Urate and Gout: A Mendelian Randomization Study

Physical activity is a potential protective factor against gout, but the role of exercise intensity in this context remains unclear. To overcome the limitations of observational studies in causal inference, this study employed a two-sample Mendelian randomization approach to explore the impact of different genetically proxied/predicted intensities of physical activity on serum urate concentration and the incidence of gout. Our data related to physical activity, serum urate, and gout were obtained from the UK Biobank, the Global Urate Genetics Consortium (GUGC), and the FinnGen dataset, respectively. Walking was included as representative of typical low-intensity physical activity in the analysis, and the other two types were moderate and vigorous physical activities. The estimation methods we used included the inverse-variance-weighted (IVW) method, MR-Egger regression, weighted-median method, simple-mode method, and weighted-mode method. Sensitivity analyses involved Rucker's framework, Cochran's Q test, funnel plots, MR-PRESSO outlier correction, and leave-one-out analysis. We found suggestive evidence from the inverse-variance-weighted method that moderate physical activity was a potential factor in reducing the incidence of gout (OR = 0.628, p = 0.034), and this association became more substantial in our subsequent sensitivity analysis (OR = 0.555, p = 0.006). However, we observed no distinctive effects of physical activity on serum urate concentration. In conclusion, our study supports some findings from observational studies and emphasizes the preventive role of moderate physical activity against gout. Given the limitations of the existing datasets, we call for future reexamination and expansion of our findings using new GWAS data.

New Inflammatory Marker Associated with Disease Activity in Gouty Arthritis: The Systemic Inflammatory Response Index

Background

The systemic immune-inflammatory index (SII) and systemic inflammatory response index (SIRI), as novel non-specific inflammatory markers, have recently drawn attention. At present, no studies have been conducted to investigate the value of SII and SIRI in gouty arthritis (GA), so we explored their possible association with GA disease activity.

Methods

The study enrolled 474 patients with acute gouty arthritis (AG), 399 patients with intercritical gouty arthritis (IG) and 194 healthy controls (HC). The differences in Monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), SII, and SIRI levels among different groups were assessed. The changes in the above indicators before and after treatment in the AG and IG groups were evaluated. Multivariate logistic regression analysis was assessed influencing factors for the acute gout attack. ROC curves were plotted to evaluate their diagnostic value for AG.

Results

Compared with the IG group, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), PLR, and incidence of hyperlipidemia in the AG group were significantly higher, and the duration of disease was significantly shorter (P < 0.05). The MLR, NLR, SII and SIRI in the AG group were significantly higher than those in the IG and HC groups (P < 0.05). Compared with baseline, decreased MLR, NLR, PLR, SII and SIRI were observed in the AG group after treatment (P < 0.05), while there was no significant difference in the IG group before and after treatment (P > 0.05). SIRI was positively correlated with ESR and CRP (P < 0.05). Multivariate logistic regression analysis result showed that duration of disease, hyperlipidemia, ESR, CRP, and SIRI were influencing factors of acute gout attack (P < 0.05). The AUC of ESR, CRP and SIRI on the diagnosis in AG were 0.664, 0.755, and 0.674, respectively.

Conclusion

SIRI may be used as a new inflammatory marker of disease activity with gouty arthritis.

The Independent Value of Neutrophil to Lymphocyte Ratio in Gouty Arthritis: A Narrative Review

Since the incidence of gouty arthritis (GA) exhibits yearly increases, accurate assessment and early treatment have significant values for improving disease conditions and monitoring prognosis. Neutrophil to lymphocyte ratio (NLR) is a common indicator in blood routine, which has the characteristics of easy access and low cost. In recent years, NLR has been proven to be an effective indicator for guiding the diagnosis, treatment, and prognosis of various diseases. Moreover, NLR has varying degrees of relationship with various inflammatory biomarkers, which can affect and reflect the inflammatory response in the body. This paper reviews the independent value of NLR for GA and its underlying molecular pathological mechanisms, intending to contribute to the further application of NLR.

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.

Knowledge and attitudes of gout patients and their perspectives about diagnosis and management: A cross-sectional study in Saudi Arabia

BACKGROUND

Gout is a chronic noncommunicable disease that might lead to multiple systemic complications if it is left untreated. The knowledge, attitudes, and perceptives among patients toward the diagnosis and management of gout are important indicators in determining the prognosis and predicting sequelae of the disease. This cross-sectional survey aimed to assess the knowledge, attitudes, and perspectives of patients diagnosed with gout toward the disease diagnosis and treatment.

METHODOLOGY

An observational cross-sectional study was conducted at university clinics and local health facilities in central Riyadh, Saudi Arabia, for the duration between April and August 2022. Pearson χ2 test was used to determine the difference in the proportion of patients who adapt different attitudes and perspectives in terms of their demographic variables. Statistical significance was defined as a p value less than .05.

RESULTS

Two-hundred thirteen patients were involved in this study. The majority of the patients (84.0%) were diagnosed for more than 1 year. The majority of the patients (76.5%) were aged 25-60 years when they were diagnosed with gout. The most common complaint at the time of the diagnosis was joint pain (73.7%). The most commonly reported gout medication treatment being used was allopurinol accounting for 23.0%. The majority of the patients (83.6%) were satisfied regarding the effects of gout management on their job performance, work life, and careers. The vast majority (97.5%) reported that they are satisfied with the health service provided.

CONCLUSION

The patients diagnosed with gout in Saudi Arabia exhibited a satisfactory level of information, attitude, and perspectives regarding their condition. The participants expressed a significant degree of satisfaction with the impact of gout management on their occupational performance, work-life balance, and professional plans. Additional research is necessary to ascertain the risk factors associated with gout and provide suitable preventative interventions.

Pro-Inflammatory of PRDM1/SIRT2/NLRP3 Axis in Monosodium Urate-Induced Acute Gouty Arthritis

PR domain-containing 1 with zinc finger domain (PRDM1) has been reported as a promoter of inflammation, which is a critical process involved in the pathogenesis of acute gouty arthritis. Herein, we sought to ascertain the function of PRDM1 in the development of acute gouty arthritis and related mechanisms. At first, peripheral blood-derived monocytes from patients with acute gouty arthritis and healthy individuals were collected as experimental samples. Then, macrophages were induced from monocytes using phorbol myristate acetate (PMA). The expression patterns of PRDM1, sirtuin 2 (SIRT2), and NLR family, pyrin domain-containing 3 (NLRP3) were characterized by RT-qPCR and Western blot assay. PMA-induced macrophages were stimulated by monosodium urate (MSU) for in vitro experimentation. Meanwhile, a murine model of MSU-induced acute gouty arthritis was established for in vivo validation. PRDM1 was highly expressed while SIRT2 poorly expressed in patients with acute gouty arthritis. Loss of PRDM1 could reduce NLRP3 inflammasome and mature IL-1β levels and downregulate inflammatory cytokines in macrophages, which contributed to protection against acute gouty arthritis. Furthermore, results showed that PRDM1 could inhibit SIRT2 expression via binding to the deacetylase SIRT2 promoter. Finally, the in vivo experiments demonstrated that PRDM1 increased NLRP3 inflammasome and mature IL-1β through transcriptional inhibition of SIRT2, whereby aggravating MSU-induced acute gouty arthritis. To sum up, PRDM1 increased NLRP3 inflammasome through inhibiting SIRT2, consequently aggravating MSU-induced acute gouty arthritis.

Gut microbiota mediated the therapeutic efficiency of Simiao decoction in the treatment of gout arthritis mice

BACKGROUND

Gut microbiota plays a significant role in the development and treatment of gouty arthritis. Simiao decoction has been shown to alleviate gouty arthritis by inhibiting inflammation, regulating NLRP3 inflammasome, and altering gut microbiota. However, there is no evidence to prove whether gut microbiota directly mediates the therapeutic efficiency of Simiao decoction in treating gout arthritis.

METHODS

In this study, fecal microbiota transplantation (FMT) was used to transfer the gut microbiota of gout arthritis mice treated with Simiao decoction or allopurinol to blank gout arthritis mice, in order to investigate whether FMT had therapeutic effects on gout arthritis.

RESULTS

Both Simiao decoction and allopurinol effectively reduced the levels of serum uric acid, liver XOD activity, foot thickness, serum IL-1β, and G-CSF in gout arthritis mice. However, Simiao decoction also had additional benefits, including raising the pain threshold, reducing serum TNF-α and IL-6, alleviating gut inflammation, and repairing intestinal pathology, which were not observed with allopurinol treatment. Moreover, Simiao decoction had a greater impact on gut microbiota than allopurinol, as it was able to restore the abundance of phylum Proteobacteria and genus Helicobacter. After transplantation into gout arthritis mice, gut microbiota altered by Simiao decoction exhibited similar therapeutic effects to those of Simiao decoction, but gut microbiota altered by allopurinol showed no therapeutic effect.

CONCLUSIONS

These findings demonstrates that Simiao decoction can alleviate gout arthritis symptoms by regulating gut microbiota.

Uric acid is independently associated with interleukin‐1β levels in tear fluid of hyperuricemia and gout patients

Objectives

To explore pro‐inflammatory cytokines status in the tear fluid of patients with hyperuricemia and gout and its association with uric acid level.

Methods

A total of 58 control subjects, 58 hyperuricemia patients including 40 asymptomatic hyperuricemia and 18 gout participants were recruited in this study. For tear analysis, each patient's tears were collected using capillary action microcaps after stimulation. Tear uric acid levels were measured using chemiluminescence. Tear and serum interleukin‐1beta (IL‐1β) and tumor necrosis factor‐alpha (TNF‐α) levels were measured using enzyme‐linked immunosorbent assay. The correlation of serum and tear uric acid levels with IL‐1β and TNF‐α were determined.

Results

Tear uric acid levels were significantly higher in hyperuricemia group (98.2 ± 51.5 vs. 42.7 ± 24.0 µmol/L, p < .001) than in controls group. IL‐1β concentrations were significantly higher in hyperuricemia eyes compared to control eyes (210.2 ± 113.9 vs. 142.6 ± 29.8 pg/mL, p < .001). Multiple linear regression analysis showed that tear uric acid levels were independently positively associated with tear IL‐1β concentrations (B = 0.192, p < .001). However, no significant correlations were found between serum or tear uric acid and TNF‐α level. Moreover, there were no statistically differences of tear IL‐1β and TNF‐α levels between the asymptomatic hyperuricemia and gout groups.

Conclusions

Tear uric acid levels were higher in patients with hyperuricemia and gout than in controls. There was a significant positive correlation between tear uric acid value and tear IL‐1β level, implying an interaction between hyperuricemia and ocular inflammation responses.

The biomarkers discovery of hyperuricemia and gout: proteomics and metabolomics

Background

Hyperuricemia and gout are a group of disorders of purine metabolism. In recent years, the incidence of hyperuricemia and gout has been increasing, which is a severe threat to people's health. Several studies on hyperuricemia and gout in proteomics and metabolomics have been conducted recently. Some literature has identified biomarkers that distinguish asymptomatic hyperuricemia from acute gout or remission of gout. We summarize the physiological processes in which these biomarkers may be involved and their role in disease progression.

Methodology

We used professional databases including PubMed, Web of Science to conduct the literature review. This review addresses the current landscape of hyperuricemia and gout biomarkers with a focus on proteomics and metabolomics.

Results

Proteomic methods are used to identify differentially expressed proteins to find specific biomarkers. These findings may be suggestive for the diagnosis and treatment of hyperuricemia and gout to explore the disease pathogenesis. The identified biomarkers may be mediators of the link between hyperuricemia, gout and kidney disease, metabolic syndrome, diabetes and hypertriglyceridemia. Metabolomics reveals the main influential pathways through small molecule metabolites, such as amino acid metabolism, lipid metabolism, or other characteristic metabolic pathways. These studies have contributed to the discovery of Chinese medicine. Some traditional Chinese medicine compounds can improve the metabolic disorders of the disease.

Conclusions

We suggest some possible relationships of potential biomarkers with inflammatory episodes, complement activation, and metabolic pathways. These biomarkers are able to distinguish between different stages of disease development. However, there are relatively few proteomic as well as metabolomic studies on hyperuricemia and gout, and some experiments are only primary screening tests, which need further in-depth study.

Single-cell RNA sequencing of immune cells in patients with acute gout

Cell subpopulations in the blood and joint fluid of patients with gout are poorly understood. Single-cell RNA sequencing and bioinformatic tools were used to identify cell subsets and their gene signatures in blood and synovial fluid (SF) cells, determine their relationships, characterize the diversity, and evaluate interactions among specific cell types. We identified 34 subpopulations (5 types of B cells, 16 types of T and natural killer cells, 9 types of monocytes, and 4 other cell types) in the blood of five healthy subjects and seven patients with acute gouty, and the SF of three patients with acute gout. We found that naïve CD4 T cells and classical monocytes cell populations were enriched in patients with gout, whereas plasmacytoid dendritic cells and intermediate monocytes were more abundant in healthy subjects. SF was enriched in Th1/Th17 cells, effector memory CD8 T cells, mucosal-associated invariant T cells, and macrophages. Subclusters of these cell subpopulations showed different compositions between healthy subjects and those with acute gout, according to blood and SF samples. At the cellular level, the inflammation score of a subpopulation or subcluster was highest in SF, following by the blood of acute gout patients and healthy person, whereas energy score showed the opposite trend. We also detected specific cell-cell interactions for interleukin-1, tumor necrosis factor-α, and transforming growth factor-β1 expression in the cells of patients with acute gout. Our study reveals cellular and molecular insights on inflammatory responses to hyperuricemia or uric crystal and may provide therapeutic guidance to improve treatments for gout.

Mechanism Investigation of Wuwei Shexiang Pills on Gouty Arthritis via Network Pharmacology, Molecule Docking, and Pharmacological Verification

Background

Gout is a common crystal-related arthritis caused by the deposition of monosodium urates (MSU). Tibetan medicine Wuwei Shexiang Pills (WSP) has been demonstrated to exhibit anti-inflammatory, antihyperuricemia, and antigout activities. However, the underlying mechanism is unknown.

Objectives

To explore the mechanisms of Wuwei Shexiang Pills on gouty arthritis via network pharmacology, molecule docking, and pharmacological verification.

Methods

The ingredients and targets of WSP were obtained by searching and screening in BATMAN-TCM and SwissADME. The targets involving the gout were acquired from public databases. The shared targets were put onto STRING to construct a PPI network. Furthermore, Metascape was applied for the GO and KEGG enrichment analysis to predict the biological processes and signaling pathways. And molecular docking was performed to validate the binding association between the key ingredients and the relative proteins of TNF signaling. Based on the serum pharmacology, the predicted antigout mechanism of WSP was validated in MSU-induced THP-1 macrophages. The levels of inflammatory cytokines and mRNA were measured by ELISA and qRT-PCR, respectively, and MAPK, NF-κB, and NLRP3 signaling-associated proteins were determined by western blot and immunofluorescence staining.

Results

48 bioactive ingredients and 165 common targets were found in WSP. The data showed that 5-Cis-Cyclopentadecen-1-One, 5-Cis-Cyclotetradecen-1-One, (−)-isoshyobunone, etc. were potential active ingredients. TNF signaling, HIF-1 signaling, and Jak-STAT signaling were predicted to be the potential pathways against gout. The molecule docking analysis found that most ingredients had a high affinity for p65, NLRP3, IL-1β, TNF-α, and p38. The data from in vitro experiment showed that WSP suppressed the production and gene expression of inflammatory cytokines. Furthermore, WSP could inhibit the activation of MAPK, NF-κB, and NLRP3 signaling pathways.

Conclusion

Our finding suggested that the antigout effect of WSP could be achieved by inhibiting MAPK, NF-κB, and NLRP3 signaling pathways. WSP might be a candidate drug for gouty treatment.

Potential molecular mechanisms of Ermiao san in the treatment of hyperuricemia and gout based on network pharmacology with molecular docking

A network pharmacology integrated molecular docking strategy was used to predict the underlying molecular mechanism of Ermiao san in the treatment of hyperuricemia and gout. Traditional Chinese medicine systems pharmacology (TCMSP) database and analysis platform were used to screen out the active compounds and their targets of Ermiao san. The disease target genes related to hyperuricemia (HUA) and gout were obtained by searching CTD, DisGeNET, DrugBank, GeneCards, OMIM, TTD, and PharmGKB databases with "Hyperuricemia" and "Gout" as keywords, respectively. The potential targets of Ermiao san in the treatment of HUA and gout were screened through a Venn diagram. The protein-protein interaction network was constructed using Cytoscape software. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were then conducted. Finally, some compounds and core targets were selected for molecular docking verification by Autodock Vina and Pymol software. Forty-six active compounds, such as quercetin, wogonin and beta-sitosterol, etc were identified. Ermiao san plays a therapeutic role in HUA and gout regulating various biological processes, cellular compounds, and molecular functions. The core targets of Ermiao san for treating HUA and gout are AT1 (namely Protein Kinase Bα), interleukin-1 beta, prostaglandin-endoperoxide synthase 2, JUN, etc. And the key pathways are nuclear factor-κB, interleukin-17 and tumor necrosis factor. The results of molecular docking analyses suggested that active compounds of Ermiao san could bind well to the core protein receptors. Ermiao san has a synergistic mechanism of multiple compounds, multiple targets, and multiple pathways in the treatment of HUA and gout, which provides a good theoretical basis for the clinical application.

Exploring RNA modifications, editing, and splicing changes in hyperuricemia and gout

Hyperuricemia and gout are two of the most common metabolic disorders worldwide; their incidence is increasing with changes in lifestyle, and they are correlated with many diseases, including renal and cardiovascular diseases. The majority of studies on hyperuricemia and gout have focused on the discovery of the associated genes and their functions and on the roles of monocytes and neutrophils in the development of gout. Virtually no studies investigating the epigenomics of gout disease or exploring the clinical significance of such research have been conducted. In this study, we observed that the expression of enzymes involved in RNA modifications or RNA editing was affected in uric acid (UA)- or monosodium urate (MSU)-treated cell lines. RNA alternative splicing and splicing factors were also affected by UA or MSU treatment. We used transcriptome sequencing to analyze genome-wide RNA splicing and RNA editing and found significant changes in RNA splicing and RNA editing in MSU- or UA-treated THP-1 and HEK293 cells. We further found significant changes of RNA modifications, editing, and splicing in patients with gout. The data indicate that RNA modifications, editing, and splicing play roles in gout. The findings of this study may help to understand the mechanism of RNA splicing and modifications in gout, facilitating the development of new diagnostic and therapeutic strategies.

Environmental factors and risk of gout

Gout is a chronic disease with inflammatory arthritis caused by monosodium urate (MSU) crystals deposition, an elevated serum urate level (hyperuricaemia) is the critical factor leading to MSU crystals deposition and promoting the progression of gout. The onset and development of gout is generally the result of multiple factors, such as diet, heredity and environmental factors. Although genetics and diet are thought to play as major factors, a growing body of research evidence has highlighted that environmental factors also play a significant role in the onset and exacerbation of gout. Recent studies have shown that air pollutants such as particulate matter, sulfur dioxide (SO₂) and carbon monoxide (CO) may increase the risk of hospitalizations for gout, and that the changes in temperature and humidity may affect uric acid (UA) levels. There is also seasonal trend in gout. It has been demonstrated that environmental factors may induce or accelerate the production and release of pro-inflammatory mediators, causing an unbalance oxidative stress and systemic inflammation, and then participating in the overall process or a certain link of gout. Moreover, several environmental factors have shown the ability to induce the production urate and regulate the innate immune pathways, involving in the pathogenesis of gout. Nevertheless, the role of environmental factors in the etiology of gout remains unclear. In this review, we summarized the recent literatures and aimed to discuss the relationship between environmental factors (such as microclimate, season, ambient/indoor air pollution and extreme weather) and gout. We further discussed the inflammatory mechanisms of environmental factors and gout and the comprehensive effects of environmental factors on gout. We also made a prospect of the management and treatment of gout, with special consideration to environmental factors associated with gout.

A Hypothesis Regarding Neurosecretory Inhibition of Stress Mediators by Colchicine in Preventing Stress-Induced Familial Mediterranean Fever Attacks

Familial Mediterranean fever (FMF) is a monogenic autoinflammatory disease characterized by recurrent episodes of fever and serositis. Colchicine (Col) has a crucial role in the prevention of amyloidosis and FMF attacks. The effect of Col on innate immune cells is based on the inhibition of the microtubule system. The microtubule system is also very important for neurosecretory functions. The inhibitory effect of Col on neurosecretory functions is an overlooked issue. Considering that the neuroimmune cross-talk process plays a role in the development of inflammatory diseases, the effect of Col on the neuronal system becomes important. FMF attacks are related to emotional stress. Therefore, the effect of Col on stress mediators is taken into consideration. In this hypothetical review, we discuss the possible effects of Col on the central nervous systems (CNS) and peripheral nervous systems (PNS) in light of mostly experimental study findings using animal models. Studies to be carried out on this subject will shed light on the pathogenesis of FMF attacks and the other possible mechanisms of action of Col apart from the anti-inflammatory features.

Characterization of Plasma Extrachromosomal Circular DNA in Gouty Arthritis

Objective: Extrachromosomal circular DNA elements (eccDNAs) are known for their broad existence in cells and plasma, which may potentially play important roles in many biological processes. Our aim was to identify potentially functional or marked eccDNAs in gout patients.

Methods: The Circle-Seq approach was applied for eccDNA detection from plasma in acute gout patients and healthy controls. Further analysis was performed on the distribution of genomic elements and eccDNA gene annotations in two groups.

Results: We detected 57,216 and 109,683 eccDNAs from the acute gout and healthy control plasma, respectively. EccDNAs were mapped to the reference genome to identify diverse classes of genomic elements and there was no significant difference of eccDNAs on genomic element annotation between gout and control group. A total of 256 eccDNA-associated genes were detected as gout unique eccDNA genes, including COL1A1 and EPB42, which potentially contribute to hyperuricemia and gout, and a couple of genes involved in inflammation or immune response. Enrichment analysis showed that these eccDNA genes were highly correlated with defense response, stress response, and immune and inflammatory responses, including T cell receptor signaling pathway, Fc epsilon RI signaling pathway, and JAK-STAT signaling pathway.

Conclusion: Our discovery reveals the novel potential biological roles of plasma eccDNAs in gouty arthritis.

Effects and underlying mechanisms of food polyphenols in treating gouty arthritis: A review on nutritional intake and joint health

Gouty arthritis, one of the most severe and common forms of arthritis, is characterized by monosodium urate crystal deposition in joints and surrounding tissues. Epidemiological evidence indicates that gouty arthritis incidence is sharply rising globally. Polyphenols are found in many foods and are secondary metabolites in plant foods. The anti-inflammatory and antioxidant effects of food polyphenols have been extensively studied in many inflammatory chronic diseases. Research has suggested that many food polyphenols have excellent anti-gouty arthritis effects. The mechanisms mainly include (a) inhibiting xanthine oxidase activity; (b) reducing the levels of inflammatory cytokines and chemokines; (c) inhibiting the activation of signaling pathways and the NLRP3 inflammasome; and (d) reducing oxidative stress. This paper reviews the research progress and pathogenesis of gouty arthritis and introduces the mechanisms of food polyphenols in treating gouty arthritis, which aims to explore the potential of functional foods in the treatment of gouty arthritis. PRACTICAL APPLICATIONS: The incidence rate of gouty arthritis has increased sharply worldwide, which has seriously affected people's quality of life. According to the current research progress, food polyphenols alleviate gouty arthritis through anti-inflammatory and antioxidant effects. This paper reviews the research progress and molecular pathogenesis of gouty arthritis and introduces the mechanisms of food-derived polyphenols in the treatment of gouty arthritis, which is helpful to the prevention and treatment of gouty arthritis.

Active Flavonoids From Lagotis brachystachya Attenuate Monosodium Urate-Induced Gouty Arthritis via Inhibiting TLR4/MyD88/NF-κB Pathway and NLRP3 Expression

Lagotis brachystachya Maxim is a characteristic herb commonly used in Tibetan medicine. Tibetan medicine records it as an important medicine for the clinical treatment of “Yellow Water Disease,” the symptoms of which are similar to that of arthritis. Our previous study showed that the flavonoid fraction extracted from L. brachystachya could attenuate hyperuricemia. However, the effects of the active flavonoids on gouty arthritis remain elusive, and the underlying mechanism is not understood. In the present study, the effects of the active flavonoids were evaluated in rats or Raw264.7 cells with gouty arthritis induced by monosodium urate (MSU) crystal, followed by the detection of TLR4, MyD88, pNF-κB, and NLR family pyrin domain-containing 3 (NLRP3) expression. The swelling of the ankle joint induced by MSU crystal began to be relieved 6 h post the administration with the active flavonoids. In addition, the active flavonoids not only alleviated MSU crystal-induced inflammation in synovial tissues by histopathological examination but also reduced tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) levels in the joint tissue fluid of MSU crystal-induced rats. Furthermore, Western blot analysis indicated that the active flavonoids reduced the production of these cytokines by inhibiting the TLR4/MyD88/NF-κB pathway and decreasing NLRP3 expression in synovial tissues of rats. More importantly, the inhibition of TLR4/MyD88/NF-κB pathway and NLRP3 expression was also confirmed in MSU-induced Raw264.7 cells. In conclusion, these results indicated that the active flavonoids from L. brachystachya could effectively attenuate gouty arthritis induced by MSU crystal through the TLR4/MyD88/NF-κB pathway and NLRP3 expression in vivo and in vitro, suggesting several potential candidates for the treatment of gouty arthritis.

Paeonol reduces IL-β production by inhibiting the activation of nucleotide oligomerization domain-like receptor protein-3 inflammasome and nuclear factor-κB in macrophages

Interleukin-1β, a key cytokine in gouty inflammation, is precisely regulated by the NLRP3 inflammasome and NF-κB. Our previous study demonstrated that paeonol suppressed IL-1β production in rats with monosodium urate (MSU)-induced arthritis. Whether NLRP3 inflammasome or NF-κB is responsible for the anti-inflammatory effect of paeonol remains unclear. In this study, J774A.1 cells induced by lipopolysaccharide (LPS) plus MSU, was used to investigate the effect of paeonol on NLRP3 inflammasome activation, and J774A.1 cells induced by LPS alone were used to investigate the effect of paeonol on NF-κB activation. In J774A.1 cells induced by LPS plus MSU, paeonol decreased the levels of IL-1β and caspase-1 and reduced the MSU-induced interaction of pro-caspase-1 and apoptosis-associated speck-like protein containing caspase recruitment domain (ASC), but did not affect the levels of pro-IL-1β and pro-caspase-1. In J774A.1 cells induced by LPS alone, paeonol reduced the levels of IL-1β, NLRP3, p-IKK, p-IκBα, and p-p65, but did not affect ASC levels. Paeonol also promoted the content of IκBα and retained more p65 in the cytoplasm. Furthermore, paeonol reduced the DNA-binding activity of p65 and lowered the levels of p-JNK, p-ERK, and p-p38. These results suggest that paeonol inhibits IL-1β production by inhibiting the activation of NLRP3 inflammasome, NF-κB, and MAPK signaling pathways.

Galectin-9 Regulates Monosodium Urate Crystal-Induced Gouty Inflammation Through the Modulation of Treg/Th17 Ratio

Gout is caused by depositing monosodium urate (MSU) crystals within the articular area. The infiltration of neutrophils and monocytes drives the initial inflammatory response followed by lymphocytes. Interestingly, emerging evidence supports the view that in situ imbalance of T helper 17 cells (Th17)/regulatory T cells (Treg) impacts the subsequent damage to target tissues. Galectin-9 (Gal-9) is a modulator of innate and adaptive immunity with both pro- and anti-inflammatory functions, dependent upon its expression and cellular location. However, the specific cellular and molecular mechanisms by which Gal-9 modulates the inflammatory response in the onset and progression of gouty arthritis has yet to be elucidated. In this study, we sought to comprehensively characterise the functional role of exogenous Gal-9 in an in vivo model of MSU crystal-induced gouty inflammation by monitoring in situ neutrophils, monocytes and Th17/Treg recruited phenotypes and related cyto-chemokines profile. Treatment with Gal-9 revealed a dose-dependent reduction in joint inflammation scores, knee joint oedema and expression of different pro-inflammatory cyto-chemokines. Furthermore, flow cytometry analysis highlighted a significant modulation of infiltrating inflammatory monocytes (CD11b⁺/CD115⁺/LY6-C^hi) and Th17 (CD4⁺/IL-17⁺)/Treg (CD4⁺/CD25⁺/FOXP-3⁺) cells following Gal-9 treatment. Collectively the results presented in this study indicate that the administration of Gal-9 could provide a new therapeutic strategy for preventing tissue damage in gouty arthritic inflammation and, possibly, in other inflammatory-based diseases.

MiR-192-5p suppresses M1 macrophage polarization via epiregulin (EREG) downregulation in gouty arthritis

Gouty arthritis (GA) is a chronic inflammatory disease characterized by the deposition of monosodium urate (MSU) crystals within joints. MiR-192-5p is shown to be low-expressed in GA patients. However, the potential mechanism involving miR-192-5p in GA remains unclear. In the current study, a significant reduction in miR-192-5p and an increase in epiregulin (EREG) were observed in serum of GA patients, suggesting that miR-192-5p and EREG were involved in the pathogenic process of GA. A mouse GA model was established via 0.5 mg/20 μL MSU crystal administration. To investigate the effect of miR-192-5p on GA, mice were injected with miR-192-5p agomir or NC agomir before modeling. We found that miR-192-5p overexpression induced by miR-192-5p agomir reduced EREG expression, attenuated ankle joint swelling and synovial inflammatory cell infiltration and improved bone erosion in MSU-induced GA mice. MiR-192-5p decreased CD16/32⁺ (M1 marker) macrophages, but increased CD206 (M2 marker) expression in synovium of GA models. In vitro, RAW264.7 macrophages were stimulated with miR-192-5p mimic or NC mimic under IFNγ plus LPS-stimulated M1 polarization condition. MiR-192-5p reduced the release of inflammatory cytokines TNF-α and IL-1β, decreased iNOS expression, and inhibited CD16/32 expression, indicating the blockade of M1 macrophage activation. Luciferase reporter system revealed the target interaction between miR-192-5p and EREG. Further rescue experiments demonstrated that EREG overexpression partly reversed the inhibitory role of miR-192-5p on M1 macrophage polarization manifested by elevated iNOS and CD16/32 levels. Collectively, miR-192-5p ameliorates inflammatory response in GA by inhibiting M1 macrophage activation via inhibiting EREG protein.

Association of low-level environmental exposure to cadmium and lead with gout flare using a cohort study design

Cadmium (Cd) and lead (Pb) are toxic heavy metals with endocrine-disrupting properties. We investigated the associations of low-level environmental exposure to Cd/Pb and gout status (intercritical gout, gout flare and combined gout) in a cohort study. We measured by ICP-MS the levels of Cd and Pb in blood (Cd-B and Pb-B) and urine (Cd-U and Pb-U) from 408 participants with blood and 346 participants with urine samples recruited from a hospital gout clinic. The median levels of Cd-B and Pb-B (in μg/L) in the gout flare group were 0.87 (range 0.41-2.49) and 31.54 (25.38-41.46), respectively, and the median levels of Cd-U and Pb-U in the gout flare group were 1.05 (0.69-1.91) and 3.86 (3.49-4.44), respectively. These medians were significantly higher than those in the control or intercritical groups (P < 0.05). For Cd-B in tertile 2 (T2) and Cd-U in tertile 3, Cd levels were significantly associated with gout flare status compared to the reference tertile 1 (OR = 4.3, P = 0.041 and OR = 25.1, P = 0.002, respectively) after adjustment under Model 3. For Pb-U, the risk of gout flare status was significantly higher in T2 (OR = 51.0, P = 0.002) compared to the T1 under Model 3. Our results show that median levels of Cd-B, Pb-B, Cd-U and Pb-U in the gout flare group were significantly higher than participants without gout or with gout but in the intercritical period. We provide evidence that the risk of gout flare status is associated with increased Cd levels, and that blood and urine levels of Cd are a risk factor for gout flare status.

Genetic Variants in Transcription Factor Binding Sites in Humans: Triggered by Natural Selection and Triggers of Diseases

Variants of transcription factor binding sites (TFBSs) constitute an important part of the human genome. Current evidence demonstrates close links between nucleotides within TFBSs and gene expression. There are multiple pathways through which genomic sequences located in TFBSs regulate gene expression, and recent genome-wide association studies have shown the biological significance of TFBS variation in human phenotypes. However, numerous challenges remain in the study of TFBS polymorphisms. This article aims to cover the current state of understanding as regards the genomic features of TFBSs and TFBS variants; the mechanisms through which TFBS variants regulate gene expression; the approaches to studying the effects of nucleotide changes that create or disrupt TFBSs; the challenges faced in studies of TFBS sequence variations; the effects of natural selection on collections of TFBSs; in addition to the insights gained from the study of TFBS alleles related to gout, its associated comorbidities (increased body mass index, chronic kidney disease, diabetes, dyslipidemia, coronary artery disease, ischemic heart disease, hypertension, hyperuricemia, osteoporosis, and prostate cancer), and the treatment responses of patients.

Cell lineage-specific methylome and genome alterations in gout

In this study, we examined data from 69 gout patients and 1,455 non-gout controls using a MethylationEPIC BeadChip assay and Illumina HiSeq platform to identify lineage-specific epigenetic alterations and associated genetic factors that contributed to gouty inflammation. Cell lineage-specific differentially methylated sites were identified using CellDMC after adjusting for sex, age, alcohol drinking, smoking status, and smoking history (total pack-years). Different cell lineages displayed distinct differential methylation. Ingenuity Pathway Analysis and NetworkAnalyst indicated that many differential methylated sites were associated with interleukin-1β expression in monocytes. On the UCSC Genome Browser and WashU Epigenome Browser, metabolic trait, cis-methylation quantitative trait loci, genetic, and functional annotation analyses identified nine methylation loci located in interleukin-1β-regulating genes (PRKCZ, CIDEC, VDAC1, CPT1A, BIRC2, BRCA1, STK11, and NLRP12) that were associated specifically with gouty inflammation. All nine sites mapped to active regulatory elements in monocytes. MoLoTool and ReMap analyses indicated that the nine methylation loci overlapped with binding sites of several transcription factors that regulated interleukin-1β production and gouty inflammation. Decreases in PRKCZ and STK11 methylation were also associated with higher numbers of first-degree relatives who also had gout. The gouty-inflammation specific methylome and genome alterations could potentially aid in the identification of novel therapeutic targets.

Potential Molecular Mechanisms of Plantain in the Treatment of Gout and Hyperuricemia Based on Network Pharmacology

Background

The incidence of gout and hyperuricemia is increasing year by year in the world. Plantain is a traditional natural medicine commonly used in the treatment of gout and hyperuricemia, but the molecular mechanism of its active compounds is still unclear. Based on network pharmacology, this article predicts the targets and pathways of effective components of plantain for gout and hyperuricemia and provides effective reference for clinical medication.

Method

Traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) and SymMap databases were used to screen out the active compounds and their targets in plantain. GeneCards, Therapeutic Target Database (TTD), and Online Mendelian Inheritance in Man (OMIM) databases were used to find the targets corresponding to gout and hyperuricemia. Venn diagram was used to obtain the intersection targets of plantain and diseases. The interaction network of the plantain active compounds-targets-pathways-diseases was constructed by using Cytoscape 3.7.2 software. Finally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were carried out.

Result

Seven active compounds were identified by network pharmacological analysis, including dinatin, baicalein, baicalin, sitosterol, 6-OH-luteolin, stigmasterol, and luteolin. Plantain plays a role in gout and hyperuricemia diseases by regulating various biological processes, cellular components, and molecular functions. The core targets of plantain for treating gout are MAPK1, RELA, TNF, NFKBIA, and IFNG, and the key pathways are pathways in cancer, hypoxia-inducible factor-1 (HIF-1) signaling pathway, interleukin (IL)-17 signaling pathway, Chagas disease (American trypanosomiasis), and relaxin signaling pathway. The core targets of plantain for hyperuricemia are RELA, MAPK1, NFKBIA, CASP3, CASP8, and TNF, and the main pathways are pathways in cancer, apoptosis, hepatitis B, IL-17 signaling pathway, and toxoplasmosis.

Conclusion

This study explored the related targets and mechanisms of plantain for the treatment of gout and hyperuricemia from the perspective of network pharmacological analysis, reflecting the characteristics of multiple components, multiple targets, and multiple pathways, and it provides a good theoretical basis for the clinical application of plantain.