Tetrandrine alleviates inflammation and promotes macrophage M2 polarization in gouty arthritis by NF-κB-mediated Lcp1.

Gouty arthritis (GA) is an inflammatory disease caused by the deposition of monosodium urate (MSU) crystals into joints. Tetrandrine (TET) is a bisbenzylisoquinoline alkaloid extracted from the root of Stephania tetrandra and can exert an anti-inflammatory function in different diseases. Nevertheless, the specific function of TET in GA remains unclear. We established the GA mouse model by MSU injection into joints of mice. Paw volume and gait score were detected for measuring the degree of joint swelling and the situation of joint dysfunction. Western blot were utilized to test the alterations of M1-related factors (IL-6, IL-1ß, TNF-α, IL-12, and iNOS) and M2-related factors (Mgl1, Mgl2, Pgc1-ß, Arg-1, and IL-10). The activity of NF-κB p65 in tissues was determined. The interaction of NF-κB p65 and Lcp1 was measured by ChIP and luciferase reporter assay. Lcp1 KO mice were utilized to detect the effect of Lcp1 depletion on GA process. TET treatment markedly suppressed MSU-induced joint swelling, joint dysfunction, and joint injury in GA mice. TET can also reduce inflammatory reactions in MUS-induced mice. Furthermore, we proved that TET facilitated M2 macrophage polarization and inhibited M1 macrophage polarization in GA mice. In addition, TET was found to inhibit NF-κB activity and NF-κB-mediated Lcp1 expression. Lcp1 knockdown can improve joint injury and promote M2 macrophage polarization in GA mice, while this effect was further enhanced by TET. TET alleviates inflammation and facilitates macrophage M2 polarization in GA by NF-κB-mediated Lcp1.

Sanmiao wan alleviates inflammation and exhibits hypouricemic effect in an acute gouty arthritis rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Sanmiao wan (SMW), a classical traditional Chinese medicine (TCM) formula, has been employed to treat gouty diseases in clinic as early as Yuan dynasty. It shows remarkably therapeutic effects in acute gouty arthritis (GA). However, the potential mechanisms of SMW are still not fully revealed. AIM OF THE STUDY: The objective of this project is to evaluate the pharmacological effects and possible mechanisms of SMW in a rat model of acute GA. MATERIALS AND METHODS: Monosodium urate (MSU) suspension was injected into the ankle joint of rats to establish acute GA model. The inflammation was evaluated by measuring the posterior ankle diameter. The pathological status of synovial tissue was assessed by hematoxylin eosin (HE), Masson, and picrosirius red staining. The level of IL-6 was measured using ELISA kit. The levels of blood urea nitrogen (BUN), creatinine (CR), UA (uric acid), and xanthine oxidase (XOD) in the serum were measured using standard diagnostic kits. The percentage of Th17 cells in blood samples was performed using flow cytometry. Moreover, RT-qPCR was performed to examine the mRNA level of RANK, RORγt, RANKL, and STAT3 in the synovial tissue. Furthermore, immunofluorescence was carried out to assess the expression of STAT3 in the synovial tissue. RESULTS: SMW effectively alleviated the inflammation and improved the pathological status of the ankle joint in rats with acute GA. It significantly suppressed the release of proinflammatory cytokine (IL-6). Meanwhile, the levels of UA, BUN, and CR were markedly reduced after SMW treatment. A remarkable reduction of XOD activity was observed in the study. Importantly, SMW treatment significantly reduced the frequency of Th17 cells, decreased the mRNA levels of RANK, RORγt, RANKL, and STAT3 in the synovial tissue. Furthermore, the suppression of STAT3 was also demonstrated using immunofluorescence in SMW-treated group. CONCLUSION: SMW showed significant anti-inflammatory and hypouricemic effects in a rat model of GA. It is an effective TCM formula for GA therapy.

Effect and mechanism of aqueous extract of Chinese herbal prescription (TFK) in treating gout arthritis.

ETHNOPHARMACOLOGICAL RELEVANCE: With the rapid development of China's economic level, great changes have taken place in people's diet structure, gout has become a common disease that puzzles people's health, seriously affects the realization of China's "Healthy China" strategic goal. Gouty arthritis (GA) is a common joint disease caused by chronic purine metabolism disorder. Currently, drugs used to treat GA are allopurinol and colchicine. However, these drugs can only temporarily relieve the clinical symptoms of GA with significant side effects. More and more basic and clinical studies have confirmed that Traditional Chinese medicine has definite curative effect on GA. AIM OF THE STUDY: To elucidate the potential molecular mechanism of Tongfengkang (TFK) in the treatment of GA, and to provide experimental basis for the search and development of efficient and low-toxicity Chinese medicine for GA treatment. MATERIALS AND METHODS: Aqueous extract of TFK (AETFK) were determined by liquid phase high resolution mass spectrometry and the possible effective constituents were screened out. Acute GA model rats were established to detect the anti-inflammatory and detumification effects of AETFK on GA and explore the potential mechanism. The effect of AETFK on serum uric acid and urinary uric acid levels in acute GA rats was determined by automatic biochemical analyzer, and the effect of AETFK on the expression of acute GA-related immunoinflammatory factors were determined by protein thermal fluorescence chip. The effect of AETFK on the concentration of neutrophils in the joint fluid of acute GA rats were determined by Reichs-Giemsa staining. The effect of AETFK on macrophage activation was detected by ELISA. In order to further investigate the mechanism of AETFK in the treatment of GA, a rat model of hyperuricemia was established to detect the effect of AETFK on the level of uric acid in hyperuricemia model rats. Biochemical indexes of liver and kidney and hematoxylin-eosin staining (HE) were used to evaluate the effects of AETFK on the organs, and to preliminatively evaluate the safety of ventilation confufang. RESULTS: Compared with the model group, the joint swelling degree of GA rats in AETFK treatment group were significantly reduced, and the levels of blood uric acid and urine uric acid were also significantly decreased. Protein thermal fluorescence microarray results showed that the levels of gout - related inflammatory factors in GA rats in AETFK treatment group were significantly lower than those in control group. Reichsen-giemsa staining and ELISA showed that AETFK could reduce the activation of macrophages and the accumulation of neutrophils in the joint fluid. The results of liver and kidney biochemical indexes and HE staining showed that no obvious tissue damage was observed in the organs of rats treated with AETFK. CONCLUSIONS: AETFK not only has significant anti-inflammatory effects on GA, but also can significantly reduce the level of blood uric acid in GA rats, without obvious toxic and side effects. These effects may be related to AETFK's inhibition of neutrophil enrichment and macrophage activation during early inflammation.

Effects of evodiamine on ROS/TXNIP/NLRP3 pathway against gouty arthritis.

Evodiamine (EVO) was tested on acute gouty arthritis rats to investigate its anti-inflammatory effect. Seventy-two male Sprague-Dawley (SD) rats were randomly assigned into the control, model, high, medium, and low dose of EVO groups and colchicine group. The ankle swelling degrees were measured at 2 h, 6 h, and 24 h following sodium urate injection into ankle joint. Histopathological examination was performed 24 h after injection. Reactive oxygen species (ROS) content in the ankle joint was detected using chemical fluorescence. Serum interleukin-1ß (IL-1ß), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) content were determined by ELISA. Serum xanthine oxidase (XOD), superoxide dismutase (SOD), and malondialdehyde (MDA) were determined by spectrophotometry. The expressions of thioredoxin-interacting protein (TXNIP), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), pro-caspase-1, caspase-1, and apoptosis-related spot like protein (ASC) in synovium were detected by Western blot. Evodiamine alleviated the ankle swelling of the affected foot in gouty arthritis rats and reduced inflammatory cell infiltration in joint synovial tissue. Evodiamine also decreased the content of serum inflammatory factors including IL-1ß, IL-18, and TNF-α, and increased serum SOD activity, while it decreased serum XOD, MDA activity, and ROS level. Moreover, evodiamine downregulated the protein expression levels of TXNIP, NLRP3, pro-caspase-1, cleaved caspae-1, and ASC. The mechanism of EVO in treating gouty arthritis is associated with the inhibition of NLRP3 inflammasome by regulating the ROS/TXNIP/NLRP3 signaling pathway.

Mechanism of DaiTongXiao in the treatment of gouty arthritis through the NLRP3 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: DaiTongXiao (DTX) is a traditional Chinese Dai folk formulation utilized for gouty arthritis treatment, with substantial evidence supporting its anti-inflammatory properties. The NLRP3 inflammasome disorder is tightly linked to the development of many inflammatory diseases. AIM OF THE STUDY: To elucidate the therapeutic efficacy of DTX in gouty arthritis and reveal its potential underlying mechanism. MATERIALS AND METHODS: The primary active constituents in DTX were determined through ultraviolet spectrophotometry and gas chromatography. Rats underwent induction with monosodium urate (MSU), followed by treatment of J774A.1 cells with adenosine triphosphate (ATP) activation and lipopolysaccharide (LPS) induction and the subsequent culture in Dulbecco's modified Eagle's medium. The degree of foot joint swelling in rats was assessed, and ankle joints were evaluated through H&E staining. Enzyme-linked immunosorbent assay was performed to measure the levels of interleukin (IL)-1ß, IL-6, IL-8, and tumor necrosis factor (TNF)-α in both serum and cells. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to determine the relative mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 macrophages. The expression of NLRP3, ASC, Caspase-1, and NF-κB was examined by western blotting. RESULTS: DTX could alleviate MSU-induced joint swelling in rats, as evidenced by a reduction in joint inflammation. Moreover, DTX effectively enhanced the survival rate of J774A.1 cells following LPS induction and ATP activation. Furthermore, DTX significantly reduced IL-1ß, IL-6, IL-8, and TNF-α levels in both cell culture medium and rat serum. RT-PCR results revealed that DTX notably downregulated the mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 cells. Additionally, DTX downregulated NLRP3, ASC, NF-κB, and Caspase-1 expression in the joint tissue. CONCLUSIONS: DTX exerts a significant anti-gouty arthritis effect, with its mechanism being tightly linked to the NLRP3 inflammatory signaling pathway. This pathway may be modulated by inhibiting IL-1ß differentiation and maturation by downregulating NLRP3, ASC, Caspase-1, and NF-κB protein expression. This, in turn, leads to a reduction in the release of IL-6, IL-8, and TNF-α, ultimately impeding gouty arthritis progression.

Articular mobilization promotes improvement in functional and inflammatory parameters in a gouty arthritis model.

OBJECTIVE: Gouty arthritis is characterized by painful inflammation due to the deposition of monosodium urate crystals in joint tissues. Despite available treatments, many patients experience ineffective management and adverse effects. This study evaluated a manual therapy protocol involving passive joint mobilization at the peak of inflammation in a gouty arthritis model using functional and inflammatory parameters. METHODS: Twenty male Wistar rats, 12 weeks old, were divided into two groups (n=10 each): Gouty Arthritis and Control Groups, which were further subdivided into treated and untreated groups (n=5 each). The Gouty Arthritis Group received intraarticular knee injection of 50µL of monosodium urate crystals, while the Control Group received 50µL of phosphate buffered saline. The treatment involved a 9-minutes session of grade III joint mobilization (according to Maitland). Nociception, grip strength, and edema were evaluated before induction (EV0), 7 hours after assessment (EV1), immediately after treatment (EV2), and 1 hour after treatment (EV3). The animals were euthanized, and synovial fluid was collected to analyze leukocyte migration. RESULTS: The model mimicked the signs of the Gouty Arthritis Group, with a decrease in the threshold of nociception and strength and an increase in edema and leukocyte count. The mobilization protocol significantly increased the nociceptive threshold and grip strength and reduced edema; however, it did not reverse the increase in leukocyte count. CONCLUSION: Our results suggest that mobilization promotes analgesia and may modulate the inflammatory process owing to reduced edema and subtle attenuation of cell migration, which contributes to strength gain.

Neutrophil autophagy induced by monosodium urate crystals facilitates neutrophil extracellular traps formation and inflammation remission in gouty arthritis.

Neutrophil extracellular traps (NETs) are composed of chromatin filaments coated with granular and cytosolic proteins, which contribute to the pathogenesis and progression of immune-related diseases. NETs are frequently observed in gouty arthritis, but the related mechanisms remain poorly understood. The aim of our study was to systematically elucidate the molecular mechanisms of self-remitting effects in gouty arthritis, and the causative relationship between neutrophil autophagy and NETs. The air pouch and paw edema model were used to simulate gouty arthritis in mice. Neutrophil infiltration and the formation of NETs were found in gouty arthritis. Interestingly, monosodium urate (MSU) crystals could induce the formation of NETs, degrade inflammatory factors, and alleviate the inflammatory response in gouty arthritis. In addition, MSU crystals resulted in profound molecular alterations in neutrophils using RNA-seq analysis, including autophagy activation. MSU crystals could activate neutrophil autophagy in vitro, and autophagy activators and inhibitors could regulate the formation of NETs. Furthermore, we explored the mechanism of autophagy-induced NETs. Autophagy related protein 7 (ATG7) produced by neutrophils stimulated with MSU crystals worked synergistically with p53 to enter the nucleus, promoting peptidyl arginine deiminase 4 (PAD4) expression, and inducing the formation of NETs. Finally, we substantiated that neutrophil autophagy regulates the severity of gouty arthritis via the formation of NETs in PAD4 -/- mice. Our results indicated that the autophagy of neutrophils regulates the formation of NETs and degrades inflammatory factors. Regulating autophagy and interfering with the formation of NETs represents a potential therapeutic approach against gouty arthritis during clinical practice.

Highly expressed long non-coding RNA SNHG14 activated MSU-induced inflammatory response in acute gout arthritis through targeting miR-223-3p.

AIM: According to reports, long non-coding RNAs (lncRNAs) are involved in the regulation of many inflammatory diseases. Here, our main purpose was to ascertain the expression data of lncRNA SNHG14 in acute gouty arthritis (AGA) and to explore its possible mechanism in the regulation of AGA. METHOD: Reverse transcription quantitative polymerase chain reaction technology was supplied to detect the lncRNA SNHG14 expression. A receiver operating characteristics curve was drawn to estimate the accuracy of lncRNA SNHG14 in AGA diagnosis. An in vitro AGA cell model was constructed by inducing THP-1 cells with monosodium urate (MSU). The concentrations of inflammatory factors such as interleukin-1ß, interleukin-6, and tumor necrosis factor-α were measured by enzyme-linked immunosorbent assay. The luciferase reporter gene was used to verify the relationship between lncRNA SNHG14 and miR-223-3p. RESULTS: In clinical analysis, the levels of serum lncRNA SNHG14 in AGA patients were significantly higher than those in the control group. Abnormally elevated lncRNA SNHG14 has high sensitivity and specificity for AGA diagnosis. In in vitro cell experiments, silencing lncRNA SNHG14 inhibited the inflammatory response of THP-1 cells stimulated by MSU, and the luciferase reporter gene proved that lncRNA SNHG14 could bind to miR-223-3p. In addition, the level of miR-223-3p declined in AGA patients and the AGA cell model. Overexpression of miR-223-3p is helpful to alleviate an MSU-induced inflammatory response. CONCLUSION: In the AGA cell model, lncRNA SNHG14, as an miR-223-3p sponge, induces a cellular inflammatory response by controlling the level of miR-223-3p, so aggravating the disease progress of AGA.

Autophagy induced by PP121 alleviates MSU crystal-induced acute gouty arthritis via inhibition of the NLRP3 inflammasome.

Acute gouty arthritis (AGA) is a frequent self-limiting inflammatory condition produced by the deposition of monosodium urate (MSU) crystals in the joints and periarticular tissues of patients with hyperuricemia. However, no effective interventional measures currently exist for AGA. Pyroptosis, a kind of pro-inflammatory programmed cell death, plays a crucial role in MSU crystal-induced inflammation and represents a potential treatment target for AGA. Therefore, we determined the therapeutic benefits and mechanism of PP121, a pyroptosis-related compound, on AGA. First, we injected an MSU crystal solution intra-articularly into the left foot pad of C57BL/6 mice to create an AGA mouse model. Subsequent treatment with PP121 substantially decreased tissue damage, pro-inflammatory cytokine release, and inflammatory cell infiltration caused by MSU crystals in the ankle joint. Consistent with these observations, the beneficial effects of PP121 on AGA were cancelled in Beclin1+/-(Becn1+/-) mice. Furthermore, after PP121 treatment, super-resolution microscopy revealed a strong relationship between lysosome-connected membrane protein/light chain 3 positive vesicles and the nucleotide-binding domain of leucine-rich family pyrin domain-containing 3 (NLPR3), demonstrating that PP121 promotes phagocytosis of the NLPR3 inflammasome. In summary, PP121-mediated autophagy can improve degradation of the NLRR3 inflammasome in AGA, which suggests the therapeutic potential of PP121 in AGA.

Discovery and Characterization of Moracin C as an Anti-Gouty Arthritis/Hyperuricemia Candidate by Docking-Based Virtual Screening and Pharmacological Evaluation.

In the present study, a natural product database of compounds associated with herbs traditionally verified to treat gout/hyperuricemia/arthritis was constructed. 3D-shape and docking-based virtual screening was conducted. To identify potential xanthine oxidase (XOD) inhibitors in the database, eight compounds with commercial availability were identified as high 3D-shape similarity with febuxostat (1), a known XOD inhibitor. Docking was used to further predict the possible interactions between XOD and these compounds. Moracin C (2), moracin D (3), and isoformononetin (8) exhibited higher docking scores and binding energies than other compounds. In vitro, 2 inhibited XOD with an IC50 value of 0.25 ± 0.14 µM, which is similar to that of 1 (0.16 ± 0.08 µM). In a hyperuricemic mouse model, 5-20 mg/kg 2 exhibited satisfying urate-lowering and XOD inhibitory effects. Compound 2 also exhibited antiarthritis activities. In RAW264.7 cells, 2 at 1-10 µM inhibited the expression of IL-1ß and TNF-α induced by MSU. In an acute gouty arthritis model in SD rats, 5-20 mg/kg 2 significantly alleviated the toe swelling, inflammatory response, and dysfunction disorder caused by monosodium urate (MSU). Compound 2 inhibited serum IL-1ß and TNF-α cytokines as well as reduced the expression of the NLRP3/ASC/caspase-1 inflammasome in joints. In summary, 2 was an effective compound for the treatment of hyperuricemia/gouty arthritis.

Tissue lipidomics, network pharmacology, and molecular docking to explore the therapeutic mechanism of anthocyanins from Lycium ruthenicum Murr. against gouty arthritis.

Lycium ruthenicum Murr. (LR) has long been used as a unique nutritional and medicinal food to treat various diseases such as gouty arthritis. However, although recently the literature has focused on the protective roles of LR anthocyanins on gouty arthritis, there is no relevant research from a holistic perspective of lipid metabolism to study their anti-gout effects. In this study, a combined tissue lipidomics, network pharmacology, and molecular docking approach was performed to investigate the intervention mechanism of LR anthocyanins against a monosodium urate (MSU)-induced gout mouse model. 54 gout-related lipid markers were identified via lipidomic profiling of the mouse knee joint, including glycerophospholipids, sphingolipids, glycerolipids, and plasmalogens. Integrating with pathway analysis, network pharmacology, and molecular docking, the potential targets of LR anthocyanins for treating gouty arthritis were predicted, while pathways in cancer, prostate cancer, sphingolipid signaling, choline metabolism in cancer, arachidonic acid metabolism, and ovarian steroidogenesis were involved as shared critical pathways of lipidomic analysis and network pharmacology. Furthermore, the binding sites and patterns of 3 active components and 4 core targets with the lowest binding energies were explored. Western blotting was finally used to verify the expression levels of 4 core proteins: MMP2, MMP9, MAP2K1, and MAPK14. These results provide new insights into our understanding of gouty arthritis and the anti-gout mechanism of LR anthocyanins.

Comparison of diagnostic efficacy of dual-energy CT and ultrasound in gouty arthritis.

OBJECTIVE: To explore the performance and effect of dual-energy computed tomography (CT) and ultrasound in the diagnosis of gouty arthritis and to provide a reference for the clinical diagnosis of gouty arthritis. METHODS: A retrospective analysis of 76 patients with gouty arthritis admitted to the hospital from June 2020 to June 2022 was conducted. Patients were diagnosed with gouty arthritis using ultrasound and dual-energy CT technology. The accuracy of diagnosis by different imaging techniques was analyzed along with the imaging findings of ultrasound and dual-energy CT. RESULTS: Seventy-six patients, 60 men and 16 women, ranging in age from 20 to 77 years (mean age 50.8 ± 10.92 years), presented with uric acid levels of 254.1-720.05 µmol/L (mean 482.17 ± 105.06 µmol/L) and C-reactive protein levels ranging from 4.25 to 10.3 mg/L. The receiver operating characteristic curve showed that the area under the curve and specificity of serum uric acid were higher by dual-energy CT than those of ultrasound in the diagnosis of gouty arthritis. The dual-energy CT detection rate of tophi was significantly higher than the ultrasound detection rate (p < .05). For inflammatory effusion and synovial thickening, the ultrasound detection rates were significantly higher than the dual-energy CT detection rates (p < .05). Regarding soft-tissue edema, the detection rate of the two methods was not significantly different (p > .05). CONCLUSION: Compared with ultrasound, dual-energy CT has increased accuracy in the diagnosis of gouty arthritis.

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-1ß 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-1ß 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.

Metabolic Regulation of Immune Response and Tissue Remodeling in Gouty Arthritis (Review).

Gouty arthritis (GA), one of the most common forms of inflammatory arthritis, is characterized by elevated serum uric acid concentrations and the consequent deposition of monosodium urate crystals. Under low-grade inflammatory stress, cells tend to adapt to the microenvironment by reprogramming their metabolic pathways. Here we review the aberrant metabolic responses to the inflammatory environment in immune and tissue cells in distinct phases of GA. Regulation of these pathways is implicated in metabolic alterations including mitochondrial dysfunction, changes in the glycolytic pathway, and alteration of lipid, uric acid, and bone metabolism among others. Investigations of how these alterations lead to proinflammatory and anti-inflammatory effects in each period of GA have revealed links to its pathogenesis. Knowledge gained may open up new opportunities for diagnosis, treatment and prognosis of GA and offer rationale for further investigation into the mechanisms underlying the progression of the disease.

Polydatin ameliorates inflammation and oxidative stress associated with MSU-induced gouty arthritis in mice by regulating PPAR-γ and ferritin activation.

AIMS: Polygonum cuspidatum Sieb. et Zucc is one of the commonly used herbs for the treatment of gouty arthritis, and polydatin is one of its main effective components. This study evaluated the therapeutic potential of polydatin for the treatment of gout. MAIN METHODS: The ankle joint of C57BL/6 mice were injected with MSU suspensions to simulate human gouty arthritis, and oral treatment with polydatin (25, 50, and 100 mg/kg body weight) was performed at 1 h after MSU crystal injection. The effect of polydatin on model mice was evaluated by measuring ankle swelling, gait, histopathological analysis, proinflammatory cytokine expression, as well as the contents of NO, MDA and GSH. The targets of polydatin were explored by Real-Time PCR and IHC. KEY FINDINGS: Treatment with polydatin inhibited ankle swelling, improved abnormal gait, and reduced ankle lesions dose-dependently. Moreover, polydatin decreased pro-inflammatory cytokine expression, and promoted expression of anti-inflammatory cytokine. In addition, polydatin inhibited MSU-induced oxidative stress by decreasing oxidative product (NO, MDA) generation and promote the antioxidant (GSH). Further, we found that polydatin reduced inflammation by decreasing the expression of NLRP3 inflammasome component via activating PPAR-γ. Moreover, polydatin can protect against iron overload and attenuate oxidative stress by promoting the activation of ferritin. SIGNIFICANCE: Our findings indicates that polydatin ameliorates MSU-induced inflammation and oxidative stress by regulating PPAR-γ and ferritin activation in gouty arthritis model mice, and this research result suggests that polydatin has therapeutic potential for the treatment of gout in humans through multiple targets.

A review on gout: Looking back and looking ahead.

Gout is a metabolic disease caused by the deposition of monosodium urate (MSU) crystals inside joints, which leads to inflammation and tissue damage. Increased concentration of serum urate is an essential step in the development of gout. Serum urate is regulated by urate transporters in the kidney and intestine, especially GLUT9 (SLC2A9), URAT1 (SLC22A12) and ABCG. Activation of NLRP3 inflammasome bodies and subsequent release of IL-1ß by monosodium urate crystals induce the crescendo of acute gouty arthritis, while neutrophil extracellular traps (NETs) are considered to drive the self-resolving of gout within a few days. If untreated, acute gout may eventually develop into chronic tophaceous gout characterized by tophi, chronic gouty synovitis, and structural joint damage, leading the crushing burden of treatment. Although the research on the pathological mechanism of gout has been gradually deepened in recent years, many clinical manifestations of gout are still unable to be fully elucidated. Here, we reviewed the molecular pathological mechanism behind various clinical manifestations of gout, with a view to making contributions to further understanding and treatment.

Myeloid Src-family kinases are critical for neutrophil-mediated autoinflammation in gout and motheaten models.

Autoinflammatory diseases include a number of monogenic systemic inflammatory diseases, as well as acquired autoinflammatory diseases such as gout. Here, we show that the myeloid Src-family kinases Hck, Fgr, and Lyn are critical for experimental models of gout, as well as for genetically determined systemic inflammation in the Ptpn6me-v/me-v (motheaten viable) mouse model. The Hck-/-Fgr-/-Lyn-/- mutation abrogated various monosodium urate (MSU) crystal-induced pro-inflammatory responses of neutrophils, and protected mice from the development of gouty arthritis. The Src-family inhibitor dasatinib abrogated MSU crystal-induced responses of human neutrophils and reduced experimental gouty arthritis in mice. The Hck-/-Fgr-/-Lyn-/- mutation also abrogated spontaneous inflammation and prolonged the survival of the Ptpn6me-v/me-v mice. Spontaneous adhesion and superoxide release of Ptpn6me-v/me-v neutrophils were also abolished by the Hck-/-Fgr-/-Lyn-/- mutation. Excessive activation of tyrosine phosphorylation pathways in myeloid cells may characterize a subset of autoinflammatory diseases.

Phospholipase A2 regulates autophagy in gouty arthritis: proteomic and metabolomic studies.

BACKGROUND: Acute gouty arthritis is inflammatory joint arthritis. Gouty arthritis (GA) involves multiple pathological processes. Deposition of joints by monosodium urate (MSU) crystals has been shown to play a critical role in the injury process. Due to the different effects of MSU stimulation on the joints, the exact changes in the synovial fluid are unknown. We want to explore the changes in proteins and metabolites in the joints of gouty arthritis. Regulating various functional substances in the joint can reduce inflammation and pain symptoms. METHODS: 10 patients with gouty knee arthritis and 10 normal controls were selected from clinical, surgical cases. The biological function of the metabolome was assessed by co-expression network analysis. A molecular network based on metabolomic and proteomic data was constructed to study critical molecules. The fundamental molecular changes in the relevant pathways were then verified by western blot. RESULTS: Proteomic analysis showed that the expressions of proteases Cathepsin B, Cathepsin D, Cathepsin G, and Cathepsin S in synovial fluid patients with gouty arthritis were significantly increased. Enrichment analysis showed a positive correlation between lysosomal and clinical inflammatory cell shape changes. Untargeted metabolomic analysis revealed that lipids and lipoids accumulate, inhibit autophagic flux, and modulate inflammation and immunity in gouty arthritis patients. It was determined that the accumulation of lipid substances such as phospholipase A2 led to the imbalanced state of the autophagy-lysosome complex, and the differentially expressed metabolites of Stearoylcarnitine, Tetradecanoylcarnitine, Palmitoylcarnitine were identified (|log2 fold change|> 1.5, adjusted P value < 0.05 and variable importance in prediction (VIP) > 1.5). The autophagy-lysosomal pathway was found to be associated with gouty knee arthritis. Essential molecular alterations of multi-omics networks in gouty knee arthritis patients compared with normal controls involve acute inflammatory response, exosomes, immune responses, lysosomes, linoleic acid metabolism, and synthesis. CONCLUSIONS: Comprehensive analysis of proteomic and untargeted metabolomics revealed protein and characteristic metabolite alterations in gouty arthritis, it mainly involves lipids and lipid like molecules, phospholipase A2 and autophagic lysosomes. This study describes the pathological characteristics, pathways, potential predictors and treatment goals of gouty knee arthritis.

Role of NLRP3 in the pathogenesis and treatment of gout arthritis.

Gout arthritis (GA) is a common and curable type of inflammatory arthritis that has been attributed to a combination of genetic, environmental and metabolic factors. Chronic deposition of monosodium urate (MSU) crystals in articular and periarticular spaces as well as subsequent activation of innate immune system in the condition of persistent hyperuricemia are the core mechanisms of GA. As is well known, drugs for GA therapy primarily consists of rapidly acting anti-inflammatory agents and life-long uric acid lowering agents, and their therapeutic outcomes are far from satisfactory. Although MSU crystals in articular cartilage detected by arthrosonography or in synovial fluid found by polarization microscopy are conclusive proofs for GA, the exact molecular mechanism of NLRP3 inflammasome activation in the course of GA still remains mysterious, severely restricting the early diagnosis and therapy of GA. On the one hand, the activation of Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome requires nuclear factor kappa B (NF-κB)-dependent transcriptional enhancement of NLRP3, precursor (pro)-caspase-1 and pro-IL-1ß, as well as the assembly of NLRP3 inflammasome complex and sustained release of inflammatory mediators and cytokines such as IL-1ß, IL-18 and caspase-1. On the other hand, NLRP3 inflammasome activated by MSU crystals is particularly relevant to the initiation and progression of GA, and thus may represent a prospective diagnostic biomarker and therapeutic target. As a result, pharmacological inhibition of the assembly and activation of NLRP3 inflammasome may also be a promising avenue for GA therapy. Herein, we first introduced the functional role of NLRP3 inflammasome activation and relevant biological mechanisms in GA based on currently available evidence. Then, we systematically reviewed therapeutic strategies for targeting NLRP3 by potentially effective agents such as natural products, novel compounds and noncoding RNAs (ncRNAs) in the treatment of MSU-induced GA mouse models. In conclusion, our present review may have significant implications for the pathogenesis, diagnosis and therapy of GA.

Component identification of modified sanmiao pills by UPLC-Xevo G2-XS QTOF and its anti-gouty arthritis mechanism based on network pharmacology and experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Modified sanmiao pills (MSMP), a traditional Chinese medicine (TCM) formula, is consisted of rhizome of Smilax glabra Roxb., Cortexes of Phellodendron chinensis Schneid., rhizome of Atractylodes chinensis (DC.) Koidz., and roots of Cyathula officinalis Kuan. in a ratio of 3:3:2:1. This formula has been broadly applied to treat gouty arthritis (GA) in China. AIMS OF THE STUDY: To elaborate the pharmacodynamic material basis and pharmacological mechanism of MSMP against GA. MATERIALS AND METHODS: UPLC-Xevo G2-XS QTOF combined with UNIFI platform was applied to qualitatively assess the chemical compounds of MSMP. Network pharmacology and molecular docking were used to identify the active compounds, core targets and key pathways of MSMP against GA. The GA mice model was established by MSU suspension injecting into ankle joint. The swelling index of ankle joint, expressions of inflammatory cytokines, and histopathological changes in mice ankle joints were determined to validate the therapeutic effect of MSMP against GA. The protein expressions of TLRs/MyD88/NF-κB signaling pathway and NLRP3 inflammasome in vivo was detected by Western blotting. RESULTS: In total, 34 chemical compounds and 302 potential targets of MSMP were ascertained, of which 28 were overlapping targets pertaining to GA. 143 KEGG enrichment pathway were obtained, of which the NOD-like receptor signaling pathway, Toll-like receptor signaling pathway, and NF-κB signaling pathway were strongly associated with GA. In silico study indicated that the active compounds had excellent binding affinity to core targets. In vivo study confirmed that MSMP observably decreased swelling index and alleviated pathological damage to ankle joints in acute GA mice. Besides, MSMP significantly inhibited the secretion of inflammatory cytokines (IL-1ß, IL-6, and TNF-α) induced by MSU, as well as the expression levels of key proteins involved in TLRs/MyD88/NF-κB signaling pathway and NLRP3 inflammasome. CONCLUSION: MSMP possessed a pronounced therapeutic effect on acute GA. Results from network pharmacology and molecular docking showed that obaculactone, oxyberberine, and neoisoastilbin might treat gouty arthritis by down-regulating TLRs/MyD88/NF-κB signaling pathway and NLRP3 inflammasome.