Hyperuricemic Mice Research Articles

Hypouricaemic and nephroprotective effects of Poria cocos in hyperuricemic mice by up-regulating ATP-binding cassette super-family G member 2

Context Poria coco F.A.Wolf (Polyporaceae) dispels dampness and promotes diuresis implying hypouricaemic action. Objective To examine hypouricaemic action of Poria coco. Materials and methods Ethanol extract (PCE) was prepared by extracting the sclerotium of P. cocos with ethanol, and the water extract (PCW) was produced by bathing the remains with water. PCE and PCW (50, 100 and 200 mg/kg, respectively) were orally administered to hyperuricemic Kunming mice (n = 8) to examine its hypouricaemic effect. Also, molecular docking was performed. Results P. cocos showed excellent hypouricaemic action, decreasing the serum uric acid of hyperuricaemia (HUA) control (526 ± 112 μmol/L) to 178 ± 53, 153 ± 57 and 151 ± 62 μmol/L (p < 0.01) by PCE and 69 ± 23, 63 ± 15 and 62 ± 20 μmol/L (p < 0.01) by PCW, respectively. According to SCrs, BUNs and H&E staining, PCE and PCW partially attenuated renal dysfunction caused by HUA. They presented no negative effects on ALT, AST and ALP activities. They elevated ABCG2 (ATP-binding cassette super-family G member 2) mRNA and protein expression in comparison to HUA control. In molecular docking, compound 267, 277, 13824, 15730 and 5759 were predicted as the top bioactives of P. cocos against HUA, which even presented better scores than the positive compound, oestrone 3-sulfate. Discussion and conclusions This paper demonstrated the hypouricaemic and nephroprotective effects of P. cocos in hyperuricemic mice by up-regulating ABCG2. These results may be useful for the development of a hypouricaemic agent.

Sonneratia apetala seed oil attenuates potassium oxonate/hypoxanthine-induced hyperuricemia and renal injury in mice.

Sonneratia apetala seeds are considered as prospective nutraceuticals with a high content of unsaturated fatty acids (UFAs) which are mainly distributed in the oil. It is well-known that UFAs could exhibit urate-lowering potency and protect against renal injury, indicating that S. apetala seed oil (SSO) may possess hypouricemic and nephroprotective effects. Consequently, the present work attempted to probe into the effects and mechanisms of SSO on potassium oxonate/hypoxanthine-induced hyperuricemia and associated renal injury. The results indicated that SSO treatment prominently inhibited the increase of serum uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) levels and hepatic xanthine oxidase (XOD) activity in hyperuricemia mice. Kidney indexes and histopathological lesions were also remarkably ameliorated. Additionally, SSO treatment improved the renal anti-oxidant status in hyperuricemia mice by significantly reversing the increase in ROS and MDA levels as well as the decline in SOD, CAT and GSH-Px activities. SSO dramatically downregulated the expression and secretion of pro-inflammatory factors involving MCP-1, IL-1β, IL-6, IL-18 and TNF-α elicited by hyperuricemia. Furthermore, after SSO treatment, increased protein expressions of GLUT9, URAT1 and OAT1 in the hyperuricemia mice were obviously reversed. SSO treatment enormously restored Nrf2 activation and subsequent translation of related anti-oxidative enzymes in the kidneys. TXNIP/NLRP3 inflammasome activation was also obviously suppressed by SSO. In conclusion, SSO exerted favorable hypouricemic effects owing to its dual functions of downregulating the XOD activity and modulating the expressions of renal urate transport-associated proteins, and it also could alleviate hyperuricemia-induced renal injury by restoring the Keap1-Nrf2 pathway and blocking the TXNIP/NLRP3 inflammasome activation.

Genistein ameliorates hyperuricemia-associated nephropathy in hyperuricemic mice

ABSTRACTHyperuricemia is a metabolic disease caused by excessive production of uric acid (UA), which can cause gout, hypertension, hyperlipidemia and other diseases. This study aimed to explore the effect of genistein on hyperuricemia and renal protection in hyperuricemic mice induced by potassium oxonate. Furthermore, genistein significantly downregulated the xanthine oxidase (XOD), adenosine deaminase levels, renal gene expressions of glucose transporter type 9 (mGLUT9) and uric acid transporter 1 (mURAT1) and upregulated organic anion transporters (mOAT1 and mOAT3) and organic cation transporters (mOCT1 and mOCT2). Additionally, genistein improved renal function, renal histopathological features and antioxidant activities in hyperuricemic mice. Genistein also attenuated renal fibrosis by suppressing the JAK2/STAT3 and Wnt/β-catenin signalling pathways in hyperuricemic mice. Overall, this study suggested that both doses of genistein have strong potential against hyperuricemia and associated disorders and may be used as natural supplements for the treatment of UA-related disorders.

Hypouricemic, hepatoprotective and nephroprotective roles of oligopeptides derived from Auxis thazard protein in hyperuricemic mice.

The oligopeptides derived from Auxis thazard protein (ATO) are a class of small peptides with molecular weight <1 kDa and good bioactivity. This paper aimed to explore the hypouricemic, hepatoprotective, and nephroprotective effects of ATO and its potential mechanisms in hyperuricemia in mice induced by potassium oxonate. The results showed that ATO significantly reduced serum UA, serum creatinine levels, inhibited XOD and ADA activities in the liver (p < 0.05), and accelerated UA excretion by downregulating the gene expression of renal mURAT1 and mGLUT9 and upregulating the gene expression of mABCG2 and mOAT1. ATO could also reduce the levels of liver MDA, increase the activities of SOD and CAT, and reduce the levels of IL-1β, MCP-1 and TNF-α. Histological analysis also showed that ATO possessed hepatoprotective and nephroprotective activities in hyperuricemic mice. Thus, ATO could reduce the serum UA level in hyperuricemic mice by decreasing UA production and promoting UA excretion from the kidney, suggesting that ATO could be developed as a dietary supplement for hyperuricemia treatment.

Withaferin A protects against hyperuricemia induced kidney injury and its possible mechanisms

ABSTRACT The study was designed to explore the effects of Withaferin A (WFA) on hyperuricemia-induced kidney injury and its action mechanism. Potassium oxonate (PO) was employed to establish the hyperuricemic mouse model. The pathological changes of renal tissue were evaluated by hematoxylin-eosin and masson trichrome staining. The levels of creatinine, blood urea nitrogen (BUN), uric acid (UA) and xanthine oxidase (XOD) were detected using corresponding commercial kits. Expressions of collagen-related and apoptosis-associated proteins in renal tissues were, respectively, evaluated by immunofluorescence and western blotting. Cell apoptosis was detected by TUNEL assay, and transporter expressions using western blotting. Followed by WFA, NRK-52E cells were treated with UA before evaluation of apoptosis and fibrosis. Results indicated that WFA ameliorated renal damage, improved kidney function, and decreased levels of creatinine, BUN, UA, and XOD in PO-induced hyperuricemic mice. Furthermore, WFA significantly prevented renal fibrosis and increased the expression of collagen-related proteins. Similarly, WFA markedly inhibited renal apoptosis, accompanied by changes of apoptosis-related proteins. Importantly, expression of transporters responsible for the secretion of organic anion transporter 1 (OAT1), OAT3, ATP-binding cassette subfamily G member 2 (ABCG2) was remarkably enhanced whereas that of urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) was reduced in renal tissues of mice with hyperuricemia. In vitro study revealed that WFA notably ameliorated UA-induced cell fibrosis and apoptosis. Taken together, WFA improves kidney function by decreasing UA via regulation of XOD and transporter genes in renal tubular cells.

Isorhamnetin, the xanthine oxidase inhibitor from Sophora japonica, ameliorates uric acid levels and renal function in hyperuricemic mice.

Hyperuricemia is a metabolic condition closely linked to xanthine oxidase (XOD) function, which is involved in the production of uric acid (UA). In this study, XOD was used as a target to construct an in vitro and in vivo activity screening and verification system. The XOD inhibition ability of the main components from the water extract of Sophorae Flos (WSF), an unopened dry flower bud of Sophora japonica, was screened by HPLC. Isorhamnetin (IRh) was identified as a major flavonoid XOD inhibitor from WSF, and we characterized its effects and potential mechanism in ameliorating UA levels and renal function in hyperuricemia model mice. Hyperuricemia was induced by oral administration of potassium oxonate (PO) and hypoxanthine to mice for 7 days. The biochemical index results showed that treatments with low, medium, and high doses of IRh (50, 100, and 150 mg kg-1) significantly reduced serum UA levels and inhibited XOD activity in serum and in the liver. Additionally, IRh effectively decreased the levels of serum creatinine and blood urea nitrogen, suggesting that it possessed nephroprotective effects in hyperuricemic mice. Furthermore, histopathological results showed that nuclear lesions and renal tubule dilatation in the kidneys of IRh-treated hyperuricemic mice were reduced, suggesting that IRh may alleviate renal injury. Molecular docking results showed that IRh combined well with XOD and is an effective XOD inhibitor. In conclusion, IRh from Sophora japonica may reduce the UA levels and alleviate renal injury by inhibiting XOD activity. It potentially functions as a therapeutic drug and dietary supplement to treat hyperuricemia.

Association of Hyperuricemia With Immune Disorders and Intestinal Barrier Dysfunction.

BackgroundMore than 30–40% of uric acid is excreted via the intestine, and the dysfunction of intestinal epithelium disrupts uric acid excretion. The involvement of gut microbiota in hyperuricemia has been reported in previous studies, but the changes and mechanisms of intestinal immunity in hyperuricemia are still unknown.MethodsThis study developed a urate oxidase (Uox)-knockout (Uox–/–) mouse model for hyperuricemia using CRISPR/Cas9 technology. The lipometabolism was assessed by measuring changes in biochemical indicators. Furthermore, 4-kDa fluorescein isothiocyanate–labeled dextran was used to assess gut barrier function. Also, 16S rRNA sequencing was performed to examine the changes in gut microbiota in mouse feces. RNA sequencing, Western blot, Q-PCR, ELISA, and immunohistochemical analysis were used for measuring gene transcription, the number of immune cells, and the levels of cytokines in intestinal tissues, serum, kidney, liver, pancreas, and vascellum.ResultsThis study showed that the abundance of inflammation-related microbiota increased in hyperuricemic mice. The microbial pattern recognition–associated Toll-like receptor pathway and inflammation-associated TNF and NF-kappa B signaling pathways were significantly enriched. The increased abundance of inflammation-related microbiota resulted in immune disorders and intestinal barrier dysfunction by upregulating TLR2/4/5 and promoting the release of IL-1β and TNF-α. The levels of epithelial tight junction proteins occludin and claudin-1 decreased. The expression of the pro-apoptotic gene Bax increased. The levels of LPS and TNF-α in systemic circulation increased in hyperuricemic mice. A positive correlation was observed between the increase in intestinal permeability and serum levels of uric acid.ConclusionHyperuricemia was characterized by dysregulated intestinal immunity, compromised intestinal barrier, and systemic inflammation. These findings might serve as a basis for future novel therapeutic interventions for hyperuricemia.

Uric acid aggravates myocardial ischemia–reperfusion injury via ROS/NLRP3 pyroptosis pathway

BackgroundThe NOD–like receptor pyrin domain–containing protein 3 (NLRP3) inflammasome activation–mediated pyroptosis pathway has been linked to myocardial ischemia–reperfusion (MI/R) injury. This study explored whether uric acid (UA) aggravates MI/R injury through NLRP3 inflammasome–mediated pyroptosis. MethodsIn vivo, a mouse MI/R model was established by ligating the left coronary artery, and a mouse hyperuricemia model was created by intraperitoneal injection of potassium oxonate (PO). Then, the myocardial infarction (MI) size; terminal deoxynucleotidyl transferase dUTP nick end–labeling (TUNEL) immunofluorescence; and serum levels of lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK–MB), and UA, as well as the expression level of pyroptosis–related protein and caspase–3 in heart tissues, were measured. Separately, primary mouse cardiomyocytes were cultured in vitro to create a hypoxia/reoxygenation (H/R) model. We then compared cardiomyocytes viability, TUNEL immunofluorescence, and the levels of LDH, reactive oxygen species (ROS), and pyroptosis–related protein and caspase–3 in cardiomyocytes. ResultsIn vivo, the MI area, levels of CK–MB and LDH, rate of cell death, and pyroptosis–related protein and the expression of caspase–3 were significantly higher in the MI/R group than in the sham group, and high UA levels worsened these changes. In vitro, cardiomyocytes viability was significantly downregulated, and the levels of ROS, LDH, pyroptosis–related protein, caspase–3, and the rate of cardiomyocyte death were significantly higher in the H/R + UA group compared with the HR group. Administration of an NLRP3 inflammasome inhibitor and ROS scavenger reversed these effects. ConclusionUA aggravates MI/R–induced activation of the NLRP3 inflammatory cascade and pyroptosis by promoting ROS generation, while inflammasome inhibitors and ROS scavengers partly reverse the injury.

Antihyperuricemic Effect of Urolithin A in Cultured Hepatocytes and Model Mice.

Hyperuricemia is defined as a disease with high uric acid (UA) levels in the blood and a strong risk factor for gout. Urolithin A (UroA) is a main microbial metabolite derived from ellagic acid (EA), which occurs in strawberries and pomegranates. In this study, we evaluated antihyperuricemic effect of UroA in both cultured hepatocytes and hyperuricemic model mice. In cultured hepatocytes, UroA significantly and dose-dependently reduced UA production. In model mice with purine bodies-induced hyperuricemia, oral administration of UroA significantly inhibited the increase in plasma UA levels and hepatic xanthine oxidase (XO) activity. In addition, DNA microarray results exhibited that UroA, as well as allopurinol, a strong XO inhibitor, induced downregulation of the expression of genes associated with hepatic purine metabolism. Thus, hypouricemic effect of UroA could be, at least partly, attributed to inhibition of purine metabolism and UA production by suppressing XO activity in the liver. These results indicate UroA possesses a potent antihyperuricemic effect and it could be a potential candidate for a molecule capable of preventing and improving hyperuricemia and gout.

Study on mechanism of Fangji Huangqi Decoction on hypouricemic effect and renal protection in hyperuricemia mice

The aim of this paper was to study the specific mechanism of Fangji Huangqi Decoction(FHT) in decreasing uric acid and improving renal function in mice with hyperuricemia(HUA) induced by potassium oxonate, so as to provide theoretical basis for the research and development of drugs for clinical prevention and treatment of HUA and the modernization of traditional Chinese medicine. Sixty Kunming male mice were randomly divided into 6 groups, with 10 mice in each group, namely normal group, model group(250 mg·kg~(-1) potassium oxonate), FHT high, medium and low-dose groups(10 920, 5 460, and 2 730 mg·kg~(-1)) and positive drug allopurinol group(5 mg·kg~(-1)). Drug administration was given once a day for 7 days. On the 6 th day, mice of each group were kept in metabolic cages, and their urine was collected for 24 hours for determination of uric acid, creatinine, and β2-microglobulin(β2-MG) levels. After 7 days, the animals were sacrificed to determine serum uric acid, creatinine β2-MG and interleukin-1β(IL-1β) levels, and their liver and kidney tissues were collected. The liver tissues were used for subsequent determination of xanthine oxidase(XOD) activity, and the kidney tissues were used for subsequent determination of IL-1β levels, pathological tests and related Western blot experiments. In the cell transfection experiment, the cells were divided into blank group, model group(4.8 mmol·L~(-1) uric acid treatment), FHT administration group(4.8 mmol·L~(-1) uric acid+200 μg·mL~(-1) FHT), leucine-rich repeat kinase 1(LRRK1)-small interfering RNA(siRNA) group(4.8 mmol·L~(-1) uric acid+LRRK1-siRNA transfection) and LRRK1-siRNA+FHT group(4.8 mmol·L~(-1) uric acid+LRRK1-siRNA transfection+200 μg·mL~(-1) FHT). After 24 h incubation, the level of IL-1β in the cell supernatant was detected, and the cellular proteins were extracted and used to determine LRRK1, epidermal growth factor receptor(EGFR), PDZ kinase 1(PDZK1) and nuclear factor-kappa B(NF-κB) protein expression levels. The results showed that, FHT could significantly reduce the uric acid, creatinine and β2-MG levels in serum and β2-MG levels in urine, increase the uric acid and creatinine levels in urine, and improve the renal pathological results of the HUA mice, but showed no effect on liver XOD activity; at the same time, we found that the expression level of IL-1β in serum and kidney, NF-κB, LRRK1 and EGFR protein levels in kidney of HUA mice were significantly increased, and the expression level of PDZK1 protein was significantly decreased, while FHT could significantly improve the abnormal expression of these proteins, and FHT increased protein expression of renal organic anion transporter 1(OAT1), OAT3 and ATP bin-ding transporter G2(ABCG2) in HUA mice, but FHT had no effect on the expression of urate transporter 1(URAT1). In the cell transfection experiment, after transfection of LRRK1-siRNA, the levels of IL-1β, EGFR and NF-κB in supernatant were significantly reduced, and the expression of PDZK1 protein was significantly increased. As compared with the LRRK1-siRNA group, the levels of IL-1β, EGFR, PDZK1 and NF-κB did not change significantly with the additional FHT. This study showed that FHT may regulate the renal uric acid transport system through LRRK1 gene, improve the capacity of uric acid excretion, so as to reduce the level of serum uric acid. At the same time, FHT can not only protect the kidney directly, but also in an indirect manner by reducing the level of uric acid.

Multiomics Integrative Analysis for Discovering the Potential Mechanism of Dioscin against Hyperuricemia Mice.

Hyperuricemia is a well-known key risk factor for gout and can cause a variety of metabolic diseases. Several studies have shown that dioscin could improve metabolic symptoms and reduce the uric acid level in blood. However, there is no comprehensive metabolomic study on the anti-hyperuricemia effects of dioscin. A total of 29 adult male Kunming mice were divided into three groups: Normal (blank), PO (potassium oxonate-administrated, 200 mg/kg/day), and Dioscin (potassium oxonate + dioscin, potassium oxonate 200 mg/kg/day, dioscin 50 mg/kg/day). All mice were treated for 42 days via oral gavage. This paper implemented an untargeted metabolomics study based on 1H NMR and LC-MS to discover the comprehensive mechanism of dioscin. Furthermore, a targeted lipidomics was fulfilled to further analyze the lipid metabolism disorder. Finally, the metabolic pathway mediated by dioscin was verified at the gene level by means of transcriptomics. The results show 53 different metabolites were closely related to the improvement of dioscin in PO-induced hyperuricemia, and 19 of them were lipids. These metabolites are mainly involved in the tricarboxylic acid cycle, lipid metabolism, amino acid metabolism, and pyrimidine metabolism. According to the transcriptomics study, the levels of 89 genes were significantly changed in the PO group compared to the normal control. Among them, six gene levels were restored by the treatment of dioscin. The six changed genes (tx1b, Tsku, Tmem163, Psmc3ip, Tcap, Tbx15) are mainly involved in the cell cycle and energy metabolism. These metabolites and genes might provide useful information for further study of the therapeutic mechanism of dioscin.

Inulin supplementation ameliorates hyperuricemia and modulates gut microbiota in Uox-knockout mice

PurposeInulin is a type of fermentable dietary fiber, which is non-digestible, and can improve metabolic function by modulating intestinal microbiota. This study aimed to evaluate the role of inulin in hyperuricemia and microbial composition of the gut microbiota in a mouse model of hyperuricemia established through knockout of Uox (urate oxidase) gene.MethodsKO (Uox-knockout) and WT (wild-type) mice were given inulin or saline by gavage for 7 weeks. The effect of inulin to combat hyperuricemia was determined by assessing the changes in serum UA (uric acid) levels, inflammatory parameters, epithelial barrier integrity, fecal microbiota alterations, and SCFA (short-chain fatty acid) concentrations in KO mice.ResultsInulin supplementation can effectively alleviate hyperuricemia, increase the expressions of ABCG2 in intestine, and downregulate expression and activity of hepatic XOD (xanthine oxidase) in KO mice. It was revealed that the levels of inflammatory cytokines and the LPS (lipopolysaccharide) were remarkably higher in the KO group than those in the WT group, indicating systemic inflammation of hyperuricemic mice, but inulin treatment ameliorated inflammation in KO mice. Besides, inulin treatment repaired the intestinal epithelial barrier as evidenced by increased levels of intestinal TJ (tight junction) proteins [ZO-1 (zonula occludens-1) and occluding] in KO mice. Moreover, serum levels of uremic toxins, including IS (indoxyl sulfate) and PCS (p-cresol sulfate), were reduced in inulin-treated KO mice. Further investigation unveiled that inulin supplementation enhanced microbial diversity and raised the relative abundance of beneficial bacteria, involving SCFAs-producing bacteria (e.g., Akkermansia and Ruminococcus). Additionally, inulin treatment increased the production of gut microbiota-derived SCFAs (acetate, propionate and butyrate concentrations) in KO mice, which was positively correlated with the effectiveness of hyperuricemia relief.ConclusionsOur findings showed that inulin may be a promising therapeutic candidate for the treatment of hyperuricemia. Moreover, alleviation of hyperuricemia by inulin supplementation was, at least, partially conciliated by modulation of gut microbiota and its metabolites.

Scutellarin Ameliorates Renal Injury via Increasing CCN1 Expression and Suppressing NLRP3 Inflammasome Activation in Hyperuricemic Mice.

Considerable evidences have indicated that elevated uric acid (UA) was involved in renal tubular injury leading to hyperuricemic nephropathy (HN). Scutellarin is a biologically active flavonoid derived from the Chinese traditional herb Erigeron breviscapus Hand-Mazz, which has been widely used in the treatment of cardiovascular and cerebrovascular diseases. In the present study, we analyzed the effect of scutellarin on HN, by using C57BL/6 mice and human renal tubular epithelial cell line HK-2 which was subjected to adenine/potassium oxonate and UA to mimic a HN injury. The HN mice showed a significant decrease in renal function with the increased SCr and blood urea nitrogen (BUN) (p < 0.05). Hematoxylin–eosin staining results showed a histological injury in HN mice kidney tissues with severe tubular damage. Scutellarin dose dependently alleviated the renal injury of the HN model (p < 0.05), and a dose of 20 mg/kg/day remarkably reduced the Scr level (26.10 ± 3.23 μmol/ml vs. 48.39 ± 7.51 μmol/ml, p < 0.05) and BUN (151.12 ± 30.24 mmol/L vs. 210.43 ± 45.67 mmol/L, p < 0.05) compared with the HN model group. Similarly, scutellarin decreased NGAL, Kim-1, cystatin C, and IL-18 protein expression levels in HN mouse (p < 0.05). Overexpressed CCN1 could not induce NLRP3 inflammasome activation, with no change of mRNA and protein expression levels of NLRP3, ASC, and pro-caspase-1 compared with the control HK-2. However, HK-2 showed a significant NLRP3 inflammasome activation and apoptosis. Importantly, knockdown of CCN1 not only aggravated NLRP3 inflammasome activation and apoptosis but also abrogated the protective effect of scutellarin in UA-induced HK-2 injury. Thus, scutellarin might alleviate HN progression via a mechanism involved in CCN1 regulation on NLRP3 inflammasome activation.

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

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. 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-1β 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. Our resultsshowed 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. In conclusion, uric acid drives intestinal barrier dysfunction through TSPO-mediated NLRP3 inflammasome.

Multiple-Purpose Connectivity Map Analysis Reveals the Benefits of Esculetin to Hyperuricemia and Renal Fibrosis.

Hyperuricemia (HUA) is a risk factor for chronic kidney disease (CKD). Serum uric acid (SUA) levels in CKD stage 3–4 patients closely correlate with hyperuricemic nephropathy (HN) morbidity. New uric acid (UA)-lowering strategies are required to prevent CKD. The multiple-purpose connectivity map (CMAP) was used to discover potential molecules against HUA and renal fibrosis. We used HUA and unilateral ureteral occlusion (UUO) model mice to verify renoprotective effects of molecules and explore related mechanisms. In vitro experiments were performed in HepG2 and NRK-52E cells induced by UA. Esculetin was the top scoring compound and lowered serum uric acid (SUA) levels with dual functions on UA excretion. Esculetin exerted these effects by inhibiting expression and activity of xanthine oxidase (XO) in liver, and modulating UA transporters in kidney. The mechanism by which esculetin suppressed XO was related to inhibiting the nuclear translocation of hexokinase 2 (HK2). Esculetin was anti-fibrotic in HUA and UUO mice through inhibiting TGF-β1-activated profibrotic signals. The renoprotection effects of esculetin in HUA mice were associated with lower SUA, alleviation of oxidative stress, and inhibition of fibrosis. Esculetin is a candidate urate-lowering drug with renoprotective activity and the ability to inhibit XO, promote excretion of UA, protect oxidative stress injury, and reduce renal fibrosis.

Baicalein alleviates hyperuricemia by promoting uric acid excretion and inhibiting xanthine oxidase

BackgroundInsufficient renal urate excretion and/or overproduction of uric acid (UA) are the dominant causes of hyperuricemia. Baicalein (BAL) is widely distributed in dietary plants and has extensive biological activities, including antioxidative, anti-inflammatory and antihypertensive activities.Purpose: To investigate the anti-hyperuricemic effects of BAL and the underlying mechanisms in vitro and in vivo. MethodsWe investigated the inhibitory effects of BAL on GLUT9 and URAT1 in vitro through electrophysiological experiments and 14C-urate uptake assays. To evaluate the impact of BAL on serum and urine UA, the expression of GLUT9 and URAT1, and the activity of xanthine oxidase (XOD), we developed a mouse hyperuricemia model by potassium oxonate (PO) injection. Molecular docking analysis based on homology modeling was performed to explain the predominant efficacy of BAL compared with the other test compounds. ResultsBAL dose-dependently inhibited GLUT9 and URAT1 in a noncompetitive manner with IC50 values of 30.17 ± 8.68 μM and 31.56 ± 1.37 μM, respectively. BAL (200 mg/kg) significantly decreased serum UA and enhanced renal urate excretion in PO-induced hyperuricemic mice. Moreover, the expression of GLUT9 and URAT1 in the kidney was downregulated, and XOD activity in the serum and liver was suppressed. The docking analysis revealed that BAL potently interacted with Trp336, Asp462, Tyr71 and Gln328 of GLUT9 and Ser35 and Phe241 of URAT1. ConclusionThese results indicated that BAL exerts potent antihyperuricemic efects through renal UA excretal promotion and serum UA production. Thus, we propose that BAL may be a promising treatment for the prevention of hyperuricemia owing to its multitargeted inhibitory activity.

Olsalazine Sodium Increases Renal Urate Excretion by Modulating Urate Transporters in Hyperuricemic Animals.

Hyperuricemia is mainly the result of relative underexcretion of urate. Urate is mainly eliminated by kidney and several important transporters expressed on the membrane of renal tubular cells involved in urate excretion. Olsalazine sodium was screened from 3167 authorized small compounds/drugs, targeting xanthine oxidoreductase. In previous study, we reported that olsalazine sodium significantly reduced the serum urate levels, and the anti-hyperuricemic activity linked with inhibiting urate formation by reducing the activity of xanthine oxidoreductase. The current research aimed to assess olsalazine sodium renal urate excretion and likely molecular mechanism. The results showed that administration of olsalazine sodium 5.0 mg/kg decreased the levels of serum urate in hyperuricemic rats, and noticeably improved the fractional excretion of urate and urate clearance, exhibiting an uricosuric action. Moreover, olsalazine sodium (2.5, 5.0, 10.0 mg/kg) reduced the level of blood urea nitrogen in rats. Further study showed that olsalazine sodium reduced the mRNA expression of urate reabsorptive transporter glucose transporter 9 (GLUT9), increased the mRNA expression of urate secretory transporters, organic anion transporter 1 (OAT1), OAT3 and type 1 sodium-dependent phosphate transporter (NPT1) as well as the protein expression of OAT3 in the kidney in hyperuricemic mice. In conclusion, olsalazine sodium exhibited a promotion of urate excretion in kidney by increasing the expression of OAT3.

Antihyperuricemic efficacy of Scopoletin-loaded Soluplus micelles in yeast extract/potassium oxonate-induced hyperuricemic mice

Scopoletin (Sco) has great potential for hyperuricemia therapy. However, the relatively low oral bioavailability of Sco limits its further applications. Soluplus-based Sco micelles (Sco-Ms) were successfully prepared in our previous work. The oral bioavailability of Sco-Ms was increased by 438% compared with free Sco. In this study, we aimed to compare the biodistribution and antihyperuricemic efficacy of Sco and Sco-Ms, and explore their therapeutic mechanisms as well. We studied the tissue biodistribution of Sco and Sco-Ms after they were orally administered to mice. The antihyperuricemic effect and the therapeutic mechanisms of Sco and Sco-Ms were evaluated using yeast extract/potassium oxonate-induced hyperuricemia model in mice. The Sco concentration in each tissue was significantly higher than that of Sco suspension after orally administrating Sco-Ms to mice. Oral delivery of Sco-Ms exhibited significantly stronger hypouricemic efficacy in hyperuricemic mice than Sco. Meanwhile, Sco-Ms showed a better protective effect on mice kidney injury. The hypouricemic efficacy of Sco was due to promoting the excretion of uric acid via modulating the alteration of gene expression levels of renal uric acid transporter (URAT1), glucose transporter (GLUT9), and organic anion transporter 1 (OAT1). Sco-Ms could not only restore the dysregulation of URAT1, GLUT9, and OAT1 more effectively, but also down-regulate the activity of hepatic xanthine oxidase (XOD) to inhibit the production of uric acid. In conclusion, taken together, Sco-Ms represents a potential oral strategy for the treatment of hyperuricemia.

Efektivitas Ekstrak Etanol Daun Durian (Durio zibethinus (Linn.)) sebagai Antihiperurisemia

Durian (Durio zibethinus Linn.) leaves are known to inhibit the xanthine oxidase enzyme which can reduce uric acid levels in the blood. The purpose of study is to determine the effectiveness of ethanol extracts of durian leaves in reducing uric acid levels in hyperuricemic mice. The mice were induced with chicken’s liver juice 0,2 mL/20 gBW and potassium oxonate 250 mg/kgBW. The animals were mice with uric acid levels above 3,3 mg/dL or 6,2-7,1 mg/dL. The study was used a completely randomized design (CRD) with six treatments and three replications, with three mice in each replications. The treatments group were K+: Allopurinol 10 mg/kgBW; K-: CMC-Na 0.5%; extracts in group P1,P2, P3, P4 are 50; 100; 200; 250 mg/kgBW. The measurements of uric acid levels were performed on day-0, day-6 after induction, and day-15 after administering each group. The data obtained were analyzed by One Way Anova test followed by Duncan's Post Hoc further test. The results showed that durian leaves could reduce uric acid levels in mice blood with the highest percentage reduction was in P2 (100 mg/kgBW) group of 40,53%, followed by P1 (50 mg/kgBW) of 38,68%. The lowest percentage was in the P4 group (250 mg/kgBW) of 22,36%, followed by the P3 group (200 mg/kgBW) of 27,71% and the ED50 value was 61,65 mg/kgBW. In conclusion, ethanol extracts of durian leaves has a significant effect on decreasing total uric acid levels in mice and has potential as an antihyperuricemia agent.

Hypouricemic effect in hyperuricemic mice and xanthine oxidase inhibitory mechanism of dietary anthocyanins from purple sweet potato (Ipomoea batatas L.)

This study was aimed to investigate the hypouricemic effect of anthocyanins from purple sweet potato in vivo and their possible interaction mechanism to xanthine oxidase (XO) in vitro. In comparison with dosage of 100 mg kg−1 anthocyanin-rich purple sweet potato extracts (APSPE), 25 mg kg−1 double acylated anthocyanins from purple sweet potato (HAA-PSP) had greater ability to reduce uric acid level and inhibit the key enzymes in uric acid production pathway. In vitro experiments indicated that HAA-PSP might be the main active component in APSPE. HAA-PSP could effectively inhibit XO activity and possibly possessed a single binding site in XO, which was of higher affinity than that of LAA-PSP. Molecular docking was performed using Discovery Studio 2018 and the results showed that HAA-PSP could strongly bind to XO, and the interaction mechanism was the insertion of acyl group of anthocyanins into the hydrophobic region of XO by interacting with certain amino acid residues. In conclusion, HAA-PSP could be developed as a dietary supplement for hyperuricemia treatment.