m(6)A methyltransferase METTL3 relieves cognitive impairment of hyperuricemia mice via inactivating MyD88/NF-κB pathway mediated NLRP3-ASC-Caspase1 inflammasome.

BACKGROUND: Recent studies have uncovered that hyperuricemia (HUA) leads to cognitive deficits, which are accompanied by neuronal damage and neuroinflammation. Here, we aim to explore the role of methyltransferase-like 3 (METTL3) in HUA-mediated neuronal apoptosis and microglial inflammation. METHODS: A HUA mouse model was constructed. The spatial memory ability of the mice was assessed by the Morris water maze experiment (MWM), and neuronal apoptosis was analyzed by the TdT-mediated dUTP nick end labeling (TUNEL) assay. Besides, enzyme-linked immunosorbent assay (ELISA) was utilized to measure the contents of inflammatory factors (IL-1ß, IL-6, and TNF-α) and oxidative stress markers (MDA, SOD, and CAT) in the serum of mice. In vitro, the mouse hippocampal neuron (HT22) and microglia (BV2) were treated with uric acid (UA). Flow cytometry was applied to analyze HT22 and BV2 cell apoptosis, and ELISA was conducted to observe neuroinflammation and oxidative stress. In addition, the expression of MyD88, p-NF-κB, NF-κB, NLRP3, ASC and Caspase1 was determined by Western blot. RESULTS: METTL3 and miR-124-3p were down-regulated, while the MyD88-NF-κB pathway was activated in the HUA mouse model. UA treatment induced neuronal apoptosis in HT22 and stimulated microglial activation in BV2. Overexpressing METTL3 alleviated HT22 neuronal apoptosis and resisted the release of inflammatory cytokines and oxidative stress mediators in BV2 cells. METTL3 repressed MyD88-NF-κB and NLRP3-ASC-Caspase1 inflammasome. In addition, METTL3 overexpression enhanced miR-124-3p expression, while METTL3 knockdown aggravated HT22 cell apoptosis and BV2 cell overactivation. CONCLUSION: METTL3 improves neuronal apoptosis and microglial activation in the HUA model by choking the MyD88/NF-κB pathway and up-regulating miR-124-3p.

Associations between serum urate and telomere length and inflammation markers: Evidence from UK Biobank cohort.

Objective: Hyperuricemia and gout have become gradually more common. The effect of serum urate on organism aging and systematic inflammation is not determined. This study aims to evaluate whether serum urate is causally associated with cellular aging markers and serum inflammation markers. Methods: A Mendelian randomization study was performed on summary-level data from the largest published genome-wide association studies. Single nucleotide polymorphisms with a genome-wide significance level were selected as instrumental variables for leukocyte telomere length (LTL), and serum soluble makers of inflammation (CRP, IL-6, TNF-α, and IGF-1). Standard inverse variance weighted (IVW) method was used as the primary statistical method. The weighted median, MR-Egger regression, and MR-PRESSO methods were used for sensitivity analysis. Results: An inverse causal association of genetically predicted serum urate levels and LTL was found using IVW method (OR: 0.96, 95%CI 0.95, 0.97; ß=-0.040; SE=0.0072; P=4.37×10-8). The association was also supported by MR results using MR-Egger method and weighted median method. The MR-PRESSO analysis and leave-one-out sensitivity analysis supported the robustness of the combined results. In terms of other aging-related serum biomarkers, there was no evidence supporting a causal effect of serum urate on CRP, IL-6, TNF-α, or IGF-1 levels. Conclusions: Serum urate levels are negatively associated with telomere length but are not associated with serum soluble indicators of inflammation. Telomere length may be a critical marker that reflects urate-related organismal aging and may be a mechanism in the age-related pathologies and mortality caused by hyperuricemia.

Inflammatory Response and Oxidative Stress as Mechanism of Reducing Hyperuricemia of Gardenia jasminoides-Poria cocos with Network Pharmacology.

Hyperuricemia (HUA) is a metabolic disease, closely related to oxidative stress and inflammatory responses, caused by reduced excretion or increased production of uric acid. However, the existing therapeutic drugs have many side effects. It is imperative to find a drug or an alternative medicine to effectively control HUA. It was reported that Gardenia jasminoides and Poria cocos could reduce the level of uric acid in hyperuricemic rats through the inhibition of xanthine oxidase (XOD) activity. But there were few studies on its mechanism. Therefore, the effective ingredients in G. jasminoides and P. cocoa extracts (GPE), the active target sites, and the further potential mechanisms were studied by LC-/MS/MS, molecular docking, and network pharmacology, combined with the validation of animal experiments. These results proved that GPE could significantly improve HUA induced by potassium oxazine with the characteristics of multicomponent, multitarget, and multichannel overall regulation. In general, GPE could reduce the level of uric acid and alleviate liver and kidney injury caused by inflammatory response and oxidative stress. The mechanism might be related to the TNF-α and IL-7 signaling pathway.

Estimate of prevalent hyperuricemia by systemic inflammation response index: results from a rural Chinese population.

OBJECTIVES: Hyperuricemia is a common metabolic disease that is intimately correlated with inflammation. Our study aimed to investigate the value of systemic inflammation response index as a novel inflammatory marker to estimate hyperuricemia in the rural Chinese population. METHODS: This cross-sectional study used the data of 8,095 Chinese men and women aged ≥35 years from the 2012-2013 Northeast China Rural Cardiovascular Health Study. RESULTS: The overall prevalence of hyperuricemia was 12.84%. After fully adjusting for potential confounders, each SD increase of SIRI in men and women caused a 21.4% and 37.0% additional risk, respectively, for hyperuricemia. Moreover, smooth curve fitting and subgroup analyses corroborated the linearity and robustness of this correlation. ROC analysis showed the ability of SIRI to estimate hyperuricemia was significantly improved in females (0.741 vs 0.745, P = 0.043), but not in males (0.710 vs 0.714, P = 0.105). The net reclassification improvement (NRI, 0.120 in men vs 0.166 in women) and integrated discrimination improvement (IDI, 0.002 in men vs 0.006 in women) showed a significant improvement for both genders. CONCLUSIONS: Our present study suggests a linear and robust relationship between SIRI and prevalent hyperuricemia, which implicates the value of SIRI to optimize the risk stratification and prevention of hyperuricemia.

Uric acid drives intestinal barrier dysfunction through TSPO-mediated NLRP3 inflammasome activation.

BACKGROUND AND AIM: Intestinal epithelial dysfunction is the foundation of various intestinal and extra-intestinal diseases, while the effects and mechanism of uric acid on the intestinal barrier are little known. TSPO has been shown to be related to the generation of ROS and is involved in regulating inflammation, whether uric acid drives intestinal epithelial dysfunction through TSPO-mediated NLRP3 inflammasome activation is unknown. METHODS: UOX gene knockout mouse (UOX-/-) were used for models of hyperuricemia. Fluorescein isothiocyanate (FITC)-labeled dextran was used to assess in vivo intestinal permeability. Serum lipopolysaccharide (LPS) and culture supernatants IL-1ß were measured using ELISA Kit. IEC-6 exposed to different concentrations of uric acid was used for in vitro experiment. Protein content and mRNA were assessed using Western blotting and Q-PCR, respectively. Intracellular ROS was determined using flow cytometry and fluorescence microscope. Mitochondrial membrane potential was detected on an immunofluorescence. Small interfering RNA transfection was used to assess the interaction between translocator protein (TSPO) and NLRP3 inflammasome. N-acetyl-L-cysteine (NAC) was used as ROS scavenger. RESULTS: Our results showed that hyperuricemia mice were characteristic by increased intestinal permeability. Hyperuricemia upregulated TSPO, increased production of ROS and activated NLRP3 inflammasome, which resulted in lower expression of occludin and claudin-1. In vitro, we showed that soluble uric acid alone increased the expression of TSPO, depolarized mitochondrial membrane potential, increased ROS release and activated NLRP3 inflammasome, which further reduced the expression of occludin and claudin-1. Silencing TSPO suppressed NLRP3 inflammasome activation and increased expression of claudin-1 and occludin, which was accompanied by lower levels of ROS. Scavenging ROS also significantly inhibited NLRP3 inflammasome activation without change of TSPO, indicating that TSPO-mediated NLRP3 inflammasome activation was dependent on ROS. CONCLUSIONS: In conclusion, uric acid drives intestinal barrier dysfunction through TSPO-mediated NLRP3 inflammasome.

Soluble Uric Acid Is an Intrinsic Negative Regulator of Monocyte Activation in Monosodium Urate Crystal-Induced Tissue Inflammation.

Although monosodium urate (MSU) crystals are known to trigger inflammation, published data on soluble uric acid (sUA) in this context are discrepant. We hypothesized that diverse sUA preparation methods account for this discrepancy and that an animal model with clinically relevant levels of asymptomatic hyperuricemia and gouty arthritis can ultimately clarify this issue. To test this, we cultured human monocytes with different sUA preparation solutions and found that solubilizing uric acid (UA) by prewarming created erroneous results because of UA microcrystal contaminants triggering IL-1ß release. Solubilizing UA with NaOH avoided this artifact, and this microcrystal-free preparation suppressed LPS- or MSU crystal-induced monocyte activation, a process depending on the intracellular uptake of sUA via the urate transporter SLC2A9/GLUT9. CD14+ monocytes isolated from hyperuricemic patients were less responsive to inflammatory stimuli compared with monocytes from healthy individuals. Treatment with plasma from hyperuricemic patients impaired the inflammatory function of CD14+ monocytes, an effect fully reversible by removing sUA from hyperuricemic plasma. Moreover, Alb-creERT2;Glut9 lox/lox mice with hyperuricemia (serum UA of 9-11 mg/dl) showed a suppressed inflammatory response to MSU crystals compared with Glut9 lox/lox controls without hyperuricemia. Taken together, we unravel a technical explanation for discrepancies in the published literature on immune effects of sUA and identify hyperuricemia as an intrinsic suppressor of innate immunity, in which sUA modulates the capacity of monocytes to respond to danger signals. Thus, sUA is not only a substrate for the formation of MSU crystals but also an intrinsic inhibitor of MSU crystal-induced tissue inflammation.

Uric acid and inflammation in kidney disease.

Asymptomatic hyperuricemia is frequently observed in patients with kidney disease. Although a substantial number of epidemiologic studies have suggested that an elevated uric acid level plays a causative role in the development and progression of kidney disease, whether hyperuricemia is simply a result of decreased renal excretion of uric acid or is a contributor to kidney disease remains a matter of debate. Over the last two decades, multiple experimental studies have expanded the knowledge of the biological effects of uric acid beyond its role in gout. In particular, uric acid induces immune system activation and alters the characteristics of resident kidney cells, such as tubular epithelial cells, endothelial cells, and vascular smooth muscle cells, toward a proinflammatory and profibrotic state. These findings have led to an increased awareness of uric acid as a potential and modifiable risk factor in kidney disease. Here, we discuss the effects of uric acid on the immune system and subsequently review the effects of uric acid on the kidneys mainly in the context of inflammation.

Structure-Based Immunogenicity Prediction of Uricase from Fungal (Aspergillus flavus), Bacterial (Bacillus subtillis) and Mammalian Sources Using Immunoinformatic Approach.

Gout is a common rheumatic condition caused due to increase in serum uric acid level (hyperuricemia). Uricase is for lowering the level of uric acid but unfortunately, it is not produced in humans due to evolutionary changes. Therefore, it is administered to humans from outside in case of the high uric acid level in blood. A different formulation of uricase from bacterial, fungal, and mammalian sources is present in the market for the treatment of hyperuricemia conditions. Uricase formulation showed immunogenic response due to the occurrence of hypersensitivity reaction during the treatment that results in poor patient compliance. The purpose of this study was to clarify the variation of Uricase immunogenicity from different sources. We have used some immunoinformatic approaches to analyze and understand some structural aspects of immunogenic and allergenic epitopes of Uricase by calculation of relative frequency for eleven global alleles. As per our knowledge, this is the first immunoinformatic study of Uricase (structural based immunogenicity prediction) that deciphered the high immunogenic nature of Uricase but no significant difference in immunogenicity was found among Uricase isolated from Aspergillus flavus, Bacillus subtillis, and mammalian source. This study gives a further lead to develop some methods (include bioengineering of less immunogenic version of the uricase or utilizing the homologous enzymes) for minimizing immune response or search new sources of uricase that could be less or non-immunogenic.

Asymptomatic hyperuricaemia: a silent activator of the innate immune system.

Asymptomatic hyperuricaemia affects ~20% of the general population in the USA, with variable rates in other countries. Historically, asymptomatic hyperuricaemia was considered a benign laboratory finding with little clinical importance in the absence of gout or kidney stones. Yet, increasing evidence suggests that asymptomatic hyperuricaemia can predict the development of hypertension, obesity, diabetes mellitus and chronic kidney disease and might contribute to disease by stimulating inflammation. Although urate has been classically viewed as an antioxidant with beneficial effects, new data suggest that both crystalline and soluble urate activate various pro-inflammatory pathways. This Review summarizes what is known about the role of urate in the inflammatory response. Further research is needed to define the role of asymptomatic hyperuricaemia in these pro-inflammatory pathways.

Urate-induced immune programming: Consequences for gouty arthritis and hyperuricemia.

Trained immunity is a process in which innate immune cells undergo functional reprogramming in response to pathogens or damage-associated molecules leading to an enhanced non-specific immune response to subsequent stimulation. While this capacity to respond more strongly to stimuli is beneficial for host defense, in some circumstances it can lead to maladaptive programming and chronic inflammation. Gout is characterized by persistent low-grade inflammation and is associated with an increased number of comorbidities. Hyperuricemia is the main risk factor for gout and is linked to the development of comorbidities. Several experimental studies have shown that urate can mechanistically alter the inflammatory capacity of myeloid cells, while observational studies have indicated an association of hyperuricemia to a wide spectrum of common adult inflammatory diseases. In this review, we argue that hyperuricemia is a main culprit in the development of the long-term systemic inflammation seen in gout. We revisit existing evidence for urate-induced transcriptional and epigenetic reprogramming that could lead to an altered functional state of circulating monocytes consisting in enhanced responsiveness and maladaptive immune responses. By discussing specific functional adaptations of monocytes and macrophages induced by soluble urate or monosodium urate crystals and their contribution to inflammation in vitro and in vivo, we further enforce that urate is a metabolite that can induce innate immune memory and we discuss future research and possible new therapeutic approaches for gout and its comorbidities.

Highly Acylated Anthocyanins from Purple Sweet Potato ( Ipomoea batatas L.) Alleviate Hyperuricemia and Kidney Inflammation in Hyperuricemic Mice: Possible Attenuation Effects on Allopurinol.

Allopurinol is the first-line medication for hyperuricemia treatment. However, severe drug-related adverse effects have often been reported among patients who received allopurinol administration. This study is aimed at evaluating the possible attenuation effects of highly acylated anthocyanins from purple sweet potato (HAA-PSP) on hyperuricemia and kidney inflammation in hyperuricemic mice treated with allopurinol. In comparison with 5 mg kg-1 allopurinol used alone, the combination of 25 mg kg-1 HAA-PSP and 2.5 mg kg-1 allopurinol could not only reduce serum uric acid level in hyperuricemic mice but also attenuate the kidney damage, as indicated by the level of serum biomarkers as well as histopathological examination. The inflammatory response was partially mitigated by inhibiting the protein expression of typical cytokines in the kidney. Our findings provide new evidence for the supplementary therapeutic potential of HAA-PSP with allopurinol on hyperuricemia and inflammation-related syndromes. Moreover, this study provides a theoretical basis for assessing the potential of anthocyanin-rich foods in health.

Pharmacological basis for use of madecassoside in gouty arthritis: anti-inflammatory, anti-hyperuricemic, and NLRP3 inhibition.

Objectives: Gouty arthritis is caused by the deposition of monosodium urate (MSU) crystals in joints, which is associated with the rise of serum urate content. This study aims to investigate the therapeutic effect of Madecassoside on gouty arthritis and hyperuricemia. Methods: DBA/1 mice were intradermally injected with MSU to stimulate joint inflammation or intraperitoneally injected with MSU to trigger peritonitis. Moreover, ICR mice were exposed to potassium oxonate to stimulate hyperuricemia. Results: Madecassoside repressed MSU-triggered pad swelling, joint 99mTc uptake, and joint inflammation in DBA/1 mice with gouty arthritis. Neutrophil infiltration and IL-1ß & IL-6 & MCP-1 secretion was also alleviated in lavage fluids from DBA/1 mice with peritonitis due to Madecassoside treatment. Furthermore, Madecassoside decreased MSU-induced neutrophil cytosolic factor 1, caspase-1 and NLRP3 expression in mice with peritoneal inflammation. In hyperuricemic mice, Madecassoside improved renal dysfunction. Serum uric acid, BUN, and creatinine were down-regulated by Madecassoside. Conclusion: These findings indicate that Madecassoside has potential to ameliorate inflammation in both acute gouty arthritis model and peritonitis model, probably via regulating IL-1ß and NLRP3 expression. Practical point: Madecassoside also exhibited a urate-lowering effect and a renal protective effect in hyperuricemic mice.

Male asymptomatic hyperuricemia patients display a lower number of NKG2D+ NK cells before and after a low-purine diet.

BACKGROUND: Aberrant activation of the immune system has been reported in asymptomatic hyperuricemia (HUA) patients. However, very few studies have elucidated the role of natural killer (NK) cells in this disease. METHODS: In this study, we evaluated the relationship between NK cells and HUA in 16 control subjects and 20 patients, who were all on a low-purine diet. We analyzed the number of circulating NK cells, its subsets, interferon-γ, and CD107 NK cells, by flow cytometry, before and after 4 and 24 weeks of diet control. We also assessed the potential association of the NK cells with clinical measures. RESULTS: The patients consistently had a lower number of NKG2D NK cells before and after low-purine diet, even the serum uric acid (SUA) levels <7 mg/dL after diet control. Moreover, a lower number of NK cells and a higher number of CD107a NK cells were observed on recruitment. Low-purine diet was benefit on the improvement of the SUA levels, body mass index (BMI), and the number and functions of NK cells. Furthermore, the number of CD3CD56 NK cells and NKG2D NK cells negatively correlated with the BMI before and after diet control. CONCLUSION: The consistent lower number of NKG2D NK cells and correlated with BMI before and after low-purine diet may be involved in the occurrence and development of HUA.

Relationship between oxidative stress and inflammation in hyperuricemia: Analysis based on asymptomatic young patients with primary hyperuricemia.

The average age of hyperuricemia patients has gradually decreased, but young patients with primary hyperuricemia often do not exhibit clinical symptoms and have not received sufficient attention. However, a lack of symptoms with primary hyperuricemia does not mean that high serum uric acid (UA) levels cannot lead to pathological effects, such as oxidative stress and inflammation, and the specific damage is still unclear. We aimed to determine the relationship between oxidative stress and inflammation to explore the possible role of pathological damage in asymptomatic young patients with primary hyperuricemia.A total of 333 participants were enrolled in our study: 158 asymptomatic young patients with primary hyperuricemia and 175 healthy persons from a health check-up population. Malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and general biochemical markers were measured.We found no differences in biochemical markers (fasting glucose, TG, TC, LDL-C, HDL-C, SCr, BUN, AST, and ALT) between the patients and healthy persons. Subsequent analyses of oxidative stress and inflammation revealed that the serum levels of MDA, IL-6, and TNF-α in the patients were significantly higher than those in the healthy control group (P < .001), and the SOD activity was significantly lower (P < .001). As the UA levels increased, MDA increased significantly and SOD decreased significantly; likewise, IL-6 and TNF-α increased significantly as the UA level increased. MDA showed a significant positive correlation with IL-6 (r = 0.367, P < .001) and TNF-α (r = 0.319, P < .001), and SOD was negatively correlated with IL-6 (r = -0.241, P < .01) and TNF-α (r = -0.308, P < .001). Multivariable logistic regression analysis showed that UA (OR: 2.379, 95% CI: 1.698-3.286, P < .001; OR: 3.261, 95% CI: 1.729-3.857, P < .001; for IL-6 and TNF-α, respectively) and MDA (OR: 1.836, 95% CI: 1.283-2.517, P < .01; OR: 2.532, 95% CI: 1.693-3.102, P < .001; for IL-6 and TNF-α, respectively) were risk factors for high IL-6 and TNF-α and that SOD (OR: 0.517, 95% CI: 0.428-0.763, P < .01; OR: 0.603, 95% CI: 0.415-0.699, P < .001; for IL-6 and TNF-α, respectively) was a protective factor.In our study, some abnormal pathological effects were found in asymptomatic young patients with hyperuricemia, suggesting that in young hyperuricemia patients, oxidative stress, inflammation and the inflammatory response may be related to the oxidative stress induced by UA. Therefore, we should pay more attention to the pathological damage caused by these alterations.

Hyperuricaemic UrahPlt2/Plt2 mice show altered T cell proliferation and defective tumor immunity after local immunotherapy with Poly I:C.

Hyperuricaemia is associated with various metabolic dysfunctions including obesity, type 2 diabetes mellitus, hypertension and in general metabolic syndrome, which are all associated with increased risk of cancer. However, the direct association between elevated uricemia and cancer mortality still remains unclear. In this study, we used a mouse model of hyperuricemia, the Urahplt2/plt2 (PLT2) mouse, to investigate the effect of high uric acid levels on anti-tumor immune responses and tumor growth. In normo-uricaemic C57BL/6 mice injected with B16 melanomas, immunotherapy by treatment with Poly I:C at the tumor site delayed tumor growth compared to PBS treatment. In contrast, Poly I:C-treated hyper-uricaemic PLT2 mice were unable to delay tumor growth. Conventional and monocyte-derived dendritic cells in the tumor-draining lymph nodes (dLN) of C57BL/6 and PLT2 mice were similarly increased after Poly I:C immunotherapy, and expressed high levels of CD40 and CD86. CD8+ T cells in the tumor-dLN and tumor of both WT and PLT2 mice were also increased after Poly I:C immunotherapy, and were able to secrete increased IFNγ upon in vitro restimulation. Surprisingly, tumor-specific CD8+ T cells in dLN were less abundant in PLT2 mice compared to C57BL/6, but showed a greater ability to proliferate even in the absence of cognate antigen. These data suggest that hyperuricaemia may affect the functionality of CD8+ T cells in vivo, leading to dysregulated T cell proliferation and impaired anti-tumor activity.

Reduction of Serum Uric Acid Associated with Attenuation of Renal Injury, Inflammation and Macrophages M1/M2 Ratio in Hyperuricemic Mice Model.

BACKGROUND: Hyperuricemia contributed to endothelial dysfunction, activation of the RAS system, increased oxidative stress and maladaptive immune system response. M1 and M2 macrophages were known to contribute to the onset of renal fibrosis. This study aimed to look at the effect of lowering serum uric acid levels on renal injury in mice. METHODS: This study used 25 male mice, 3 months old, that divided into 5 groups. We injected uric acid intraperitoneally, 125mg/kg/day for 7 days (UA7) and 14 days (UA14), to induce hyperuricemia and then gave allopurinol 50mg/kg/day for 7 days to lower serum uric acid levels (UA7AL7 and UA14AL7). At the end of the treatment, we measured serum uric acid levels, Glomerular Injury Score (GIS) and Arteriolar Injury Score (AIS) with PAS staining, eNOS and MCP-1 expression with Reverse Transcriptase-PCR (RT-PCR), macrophages M1/M2 ratio with anti-CD68 and anti-arginase I immunohistochemical staining. Data were analyzed by one-way ANOVA and Kruskal-Wallis test. RESULTS: Uric acid injection increased serum uric acid levels in UA7 and UA14 group (p<0.05), followed by the increase in GIS and AIS. RT-PCR showed increased expression of MCP-1 and decreased expression of eNOS. M1 macrophages count was higher than control in UA7 and UA14 whereas M2 macrophages did not show any increased count, so the ratio of macrophages M1 / M2 is higher. Decrease in serum uric acid levels reduced GIS, AIS, MCP-1 expression and macrophages M1/M2 ratio (p<0.05). CONCLUSION: Reduction of serum uric acid levels significantly reduced renal injury that occurred in mice model of hyperuricemia.

A Novel Multi-Epitope Vaccine Based on Urate Transporter 1 Alleviates Streptozotocin-Induced Diabetes by Producing Anti-URAT1 Antibody and an Immunomodulatory Effect in C57BL/6J Mice.

Hyperuricemia (HUA) is related to diabetes. Uric acid-induced inflammation and oxidative stress are risk factors for diabetes and its complications. Human urate transporter 1 (URAT1) regulates the renal tubular reabsorption of uric acid. IA-2(5)-P2-1, a potent immunogenic carrier designed by our laboratory, can induce high-titer specific antibodies when it carries a B cell epitope, such as B cell epitopes of DPP4 (Dipeptidyl peptidase-4), xanthine oxidase. In this report, we describe a novel multi-epitope vaccine composing a peptide of URAT1, an anti-diabetic B epitope of insulinoma antigen-2(IA-2) and a Th2 epitope (P2:IPALDSLTPANED) of P277 peptide in human heat shock protein 60 (HSP60). Immunization with the multi-epitope vaccine in streptozotocin-induced diabetes C57BL/6J mice successfully induced specific anti-URAT1 antibody, which inhibited URAT1 action and uric acid reabsorption, and increased pancreatic insulin level with a lower insulitis incidence. Vaccination with U-IA-2(5)-P2-1 (UIP-1) significantly reduced blood glucose and uric acid level, increased Th2 cytokines interleukin (IL)-10 and IL-4, and regulated immune reactions through a balanced Th1/Th2 ratio. These results demonstrate that the URAT1-based multi-epitope peptide vaccine may be a suitable therapeutic approach for diabetes and its complications.

Caffeoylquinic acid derivatives rich extract from Gnaphalium pensylvanicum willd. Ameliorates hyperuricemia and acute gouty arthritis in animal model.

BACKGROUND: The Gnaphalium pensylvanicum willd. is used in China as a folk medicine to treat anti-inflammatory, cough and rheumatism arthritis. The aim of this study was to evaluate the potential of the extract of G. pensylvanicum to treat hyperuricemia and acute gouty arthritis in animal model. METHODS: G. pensylvanicum extract was evaluated in an experimental model with potassium oxonate (PO) induced hyperuricemia in mice which was used to evaluate anti-hyperuricemia activity and xanthine oxidase (XO) inhibition. Therapies for acute gouty arthritis was also investigated on monosodium urate (MSU) crystal induced paw edema model. RESULTS: G. pensylvanicum extract showed activity in reducing serum uric acid (Sur) through effect renal glucose transporter 9 (GLUT9), organic anion transporter 1 (OAT1) and urate transporter 1 (URAT1) mainly and inhibited XO activity in vivo of mice with PO induced hyperuricemia. The extract of G. pensylvanicum also showed significant anti-inflammatory activity and reduced the paw swelling on MSU crystal-induced paw edema model. Meanwhile, 13 caffeoylquinic acid derivatives and 1 flavone were identified by UPLC-ESI-MS/MS as the main active component of G. pensylvanicum. CONCLUSIONS: The extract of G. pensylvanicum showed significant effect on evaluated models and therefore may be active agents for the treatment of hyperuricemia and acute gouty arthritis.

Anti-hyperuricemic and anti-inflammatory actions of vaticaffinol isolated from Dipterocarpus alatus in hyperuricemic mice.

The present study was designed to examine the anti-hyperuricemic and anti-inflammatory effects and possible mechanisms of vaticaffinol, a resveratrol tetramer isolated from ethanol extracts of Dipterocarpus alatus, in oxonate-induced hyperuricemic mice. At 1 h after 250 mg·kg-1 potassium oxonate was given, vaticaffinol at 20, 40, and 60 mg·kg-1 was intragastrically administered to hyperuricemic mice once daily for seven consecutive days. Vaticaffinol significantly decreased serum uric acid levels and improved kidney function in hyperuricemic mice. It inhibited hepatic activity of xanthine dehydrogenase (XDH) and xanthine oxidase (XOD), regulated renal mRNA and protein levels of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporter 1 (OAT1), organic cation transporter 1 (OCT1), OCT2, organic cation/carnitine transporter 1 (OCTN1), and OCTN2 in hyperuricemic mice. Moreover, vaticaffinol markedly down-regulated renal protein levels of NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like (ASC), and Caspase-1, resulting in the reduction of interleukin (IL)-1ß, IL-18, IL-6 and tumor necrosis factor-α (TNF-α) levels in this animal model. Additionally, HPLC and LC-MS analyses clearly testified the presence of vaticaffinol in the crude extract. These results suggest that vaticaffinol may be useful for the prevention and treatment of hyperuricemia with kidney inflammation.

Polydatin attenuates potassium oxonate-induced hyperuricemia and kidney inflammation by inhibiting NF-κB/NLRP3 inflammasome activation via the AMPK/SIRT1 pathway.

This study was designed to investigate the effects of polydatin (PLD) on potassium oxonate-induced hyperuricemic rats. Hyperuricemic rats were treated with potassium oxonate (250 mg kg-1) intragastrically for 7 days, and polydatin (25, 50 mg kg-1) or allopurinol (5 mg kg-1) was administered to the rats 1 h after the potassium oxonate exposure. Polydatin administration decreased the levels of uric acid and creatinine in serum and urine, leading to inhibition of pro-inflammatory cytokine production in serum and kidney. Western blot analyses illustrated that polydatin down-regulated the translocation of NF-κB p65, the degradation of IκBα, and the protein levels of inflammasome components (NLRP3, ASC, and caspase-1), which led to reduced IL-1ß secretion. Notably, polydatin treatment activated AMP kinase (AMPK) protein and increased SIRT1 expression. Taken together, polydatin might be a promising agent for gouty treatment to inhibit renal NF-κB/NLRP3 inflammasome activation via the AMPK/SIRT1 pathway.