Bergenin as a Novel Urate-Lowering Therapeutic Strategy for Hyperuricemia

Identification of the WRKY gene family in Bergenia purpurascens and functional analysis of BpWRKY13 under cold stress

Bergenia purpurascens, a medicinal alpine plant, exhibits remarkable stress resilience. WRKY transcription factors are central regulators of plant stress responses, yet their family in B. purpurascens remains uncharacterized. Here, we identified 57 BpWRKY genes from B. purpurascens transcriptome data. Expression analysis revealed 11 BpWRKY genes differentially expressed under cold stress, with BpWRKY13 showing the strongest induction. To investigate its function, we overexpressed BpWRKY13 in Arabidopsis thaliana. Transgenic plants displayed significantly enhanced cold tolerance, evidenced by reduced leaf damage, increased survival, and elevated accumulation of proline and soluble proteins. Furthermore, transgenic plants exhibited increased activity of antioxidant enzymes and upregulation of cold-responsive genes. These findings indicate that BpWRKY13 confers cold tolerance by promoting osmoprotection and activating antioxidant defense mechanisms. This study provides a crucial foundation for understanding the BpWRKY gene family and highlights BpWRKY13 as a key regulator of cold resistance in B. purpurascens.

Identification and expression pattern analysis of BpGRAS gene family in Bergenia purpurascens and functional characterization of BpGRAS9 in salt tolerance

Bergenia purpurascens is an important medicinal, edible, and ornamental plant. It generally grows in extreme environments with complex stresses. The GRAS transcription factors play a crucial role in regulating plant stress tolerance and growth-development. There is no research on GRAS transcription factors in B. purpurascens. In this study, 29 B. purpurascens GRAS (BpGRAS) genes were identified based on B. purpurascens transcriptome data. These BpGRAS genes were classified into seven subfamilies according to phylogenetic analysis, while BpGRAS1 was not classified into any other subfamilies. The motif analysis showed that the protein motifs in the same subfamily were relatively conserved. The expression pattern analysis of BpGRAS genes in different tissues and under salt stress showed that eight BpGRAS genes were differentially expressed under salt stress. The expression profiles showed that BpGRAS9 might play an important role in salt response and the transgenic Arabidopsis thaliana lines with overexpressed BpGRAS9 showed the enhanced salt tolerance. Root length and fresh weight were significantly increased in transgenic lines under salt conditions. The studies enhanced our comprehension of the function of BpGRAS and established a more foundation for exploring the molecular mechanisms underlying plant salt tolerance.

Combination of potassium oxonate with anti-PD-1 for the treatment of colorectal cancer

Introduction

Identification of effective therapies for colorectal cancer (CRC) remains an urgent medical need, especially for the microsatellite stable (MSS) phenotype. In our previous study, potassium oxonate (PO), a uricase inhibitor commonly used for elevating uric acid in mice, unexpectedly showed remarkable inhibition of tumor growth when combined with anti-programmed death-1 (PD-1). Further research demonstrated that the combination of potassium oxonate and anti-PD-1 could reprogram the immune microenvironment. This study aimed to explore the anti-tumor effect of PO combined with anti-PD-1, and investigate the impact on the immunosuppressive tumor microenvironment (TME).

Methods

We established a syngeneic mouse model of CRC and divided into groups of control group, single drugs group of PO and anti-PD-1, and the combination group. Use the HE staining, immunohistochemistry (IHC) and TUNEL staining of tumor issues to verify the anti-neoplasm of each group. We also tested the changes of TME through flow cytometry of spleen of mice in each group, as well as the IHC of cytokines.

Results

The co-therapy of PO and anti-PD-1 showed admirable anti-tumor effect compared with the control group and the single drug groups. The TME were tended to an environment beneficial for killing tumors by enhancing chemotactic factor release, increasing CD8+ T cell infiltration and activation, and decreasing the amount of regulatory T cells. Moreover, IFN-γ and IL-2 secretion were found to be enriched in the tumor TME.

Conclusion

Our study indicated that combination of PO and anti-PD-1 could synergistically suppress CRC progression and altered the tumor microenvironment in favor of antitumor immune responses.

Therapeutic potential and pharmacological mechanisms of Traditional Chinese Medicine in gout treatment

Gout is a systemic metabolic disorder caused by elevated uric acid (UA) levels, affecting over 1% of the population. The most common complication of gout is gouty arthritis (GA), characterized by swelling, pain or tenderness in peripheral joints or bursae, which can lead to the formation of tophi. At present, western medicines like colchicine, febuxostat and allopurinol are the primary treatment strategy to alleviate pain and prevent flare-ups in patients with GA, but they have significant side effects and increased mortality risks. Traditional Chinese medicine (TCM) has been utilized for thousands of years for the prevention and treatment of GA, demonstrating effective control over serum UA (SUA) levels with fewer side effects. Herein we summarized a total of 541 studies published from 2000 to 2023 in sources including PubMed, Web of Science, the Cochrane Library and Embase, highlighting the therapeutic potential of TCM in treating gout and GA, particularly in combination with modern medical strategies. This review focuses on TCM formulas, Chinese herbal extracts, and active compounds derived from TCM, providing an overview of recent clinical application and the pharmacological research based on animal models and cellular systems. Particularly, the current review categorized the clinical and experimental evidence into the strategies for improving hyperuricemia, decreasing the sudden onset of acute GA and retarding chronic GA progression, supplied further coherent reference and enlightenment for clinicians, investigators of natural product chemistry, researchers in TCM and pharmacology. We hope this article will inspire the development of novel formulas and molecular entities for the treatment of gout and GA.

Serum uric acid and mortality in metabolic dysfunction-associated steatotic liver disease: Subgroup differences

BACKGROUND AND AIMS

This study aims to investigate the association between serum uric acid (SUA) and both the risk and long-term mortality of dysfunction-associated steatotic liver disease (MASLD), and to explore differences between the pure MASLD and metabolic and alcohol related/associated liver disease (MetALD) subgroups.

METHODS AND RESULTS

We included 11,675 participants from the Third National Health and Nutrition Examination Survey, with matched mortality data up to 2019. Logistic regression and Cox proportional hazards regression evaluated the relationship between SUA and both the risk and mortality of MASLD. Non-linear correlations and threshold effects were explored using restricted cubic splines and a two-piecewise Cox proportional hazards model. We found that SUA was positively associated with the risk of MASLD [odds ratio (OR): 1.19, 95 % confidence interval (CI) 1.12-1.27]. For pure MASLD, SUA showed a positive association with all-cause mortality [<4.7 mg/dL: hazard ratio (HR): 1.34, 95 % CI 1.04-1.73; ≥4.7 mg/dL: HR: 1.08, 95 % CI 1.02-1.15] and cardiovascular mortality (HR: 1.12, 95 % CI 1.02-1.22). For MetALD, there was an inverse J-shaped relationship (threshold: 6.6 mg/dL) between SUA and all-cause mortality. Below the threshold, SUA was negatively correlated with all-cause mortality (HR: 0.42, 95 % CI 0.19-0.93), but no association was found above it (HR: 0.81, 95 % CI 0.54-1.21). Additionally, no association was observed between SUA and cardiovascular mortality.

CONCLUSIONS

SUA serves as an independent predictor of the risk and all-cause mortality of MASLD. The relationship between SUA and both all-cause and cardiovascular mortality differs between the pure MASLD and MetALD subgroups.

Probiotic Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 improved liver function and uric acid management-A pilot study

Metabolic-associated fatty liver disease (MAFLD) is predominantly associated with metabolic disturbances representing aberrant liver function and increased uric acid (UA) levels. Growing evidences have suggested a close relationship between metabolic disturbances and the gut microbiota. A placebo-controlled, double-blinded, randomized clinical trial was therefore conducted to explore the impacts of daily supplements with various combinations of the probiotics, Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 with a focus on liver function and serum UA levels. Test subjects with abnormal levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and UA were recruited and randomly allocated into six groups. Eighty-two participants successfully completed the 60-day intervention without any dropouts or occurrence of adverse events. The serum AST, ALT, and UA levels were significantly reduced in all treatment groups (P < 0.05). The fecal microbiota analysis revealed the intervention led to an increase in the population of commensal bacteria and a decrease in pathobiont bacteria, especially Bilophila wadsworthia. The in vitro study indicated the probiotic treatments reduced lipid accumulation and inflammatory factor expressions in HepG2 cells, and also promoted UA excretion in Caco-2 cells. The supplementation of multi-strain probiotics (TSF331, TSR332, and TSP05) together can improve liver function and UA management and may have good potential in treating asymptomatic MAFLD. Trial registration. The trial was registered in the US Library of Medicine (clinicaltrials.gov) with the number NCT06183801 on December 28, 2023.

Microwave extraction and molecular imprinted polymer isolation of bergenin applied to the dendrochronological chemical study of Peltophorum dubium

This study describes methodologies for extracting and isolating bergenin, a C-glucoside of 4-O-methylgallic acid found in some plants and it presents various in vitro and in vivo biological activities. Bergenin was previously obtained from the Pelthophorum dubim (Fabaceae) roots with a good yield. Conventional chromatographic procedures of the CHCl3 soluble fraction of the MeOH extract gave 3.62% of this glucoside. An HPLC/DAD method was also developed and validated for bergenin and its precursor, gallic acid quantifications. Microwave extractions with different solvents were tested to optimize the extraction of bergenin, varying the temperature and time. MAE (Microwave Assisted Extraction) was more efficient than conventional extraction procedures, giving a higher yield of bergenin per root mass (0.45% vs. 0.0839%). Molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) based on bergenin as the template molecule, methacrylic acid, and ethylene glycol dimethacrylate were synthesized and characterized by FTIR and SEM (Scanning Electron Microscopy). Bergenin adsorption experiments using MIP and NIP followed by molecular imprinted solid phase extraction (MISPE) showed that MIP had a higher selectivity for bergenin than NIP. A dendrochronological study using the proposed method for detection and quantification of gallic acid and bergenin in five P. dubium growth rings of a 31-year-old heartwood and in the phelloderm and barks indicated that bergenin was more abundant in the 11-14th growth rings of the heartwood and decreased from the heartwood to the barks.

Bacaba, Pracaxi and Uxi Oils for Therapeutic Purposes: A Scoping Review

Fruits such as bacaba (Oenocarpus bacaba Mart), pracaxi (Pentaclethra macroloba Kuntze) and uxi (Endopleura uchi (Huber) Cuatrec), from the Amazon rainforest, are potentially interesting for studies of natural products. The current article aims at mapping and characterizing studies on the bacaba, pracaxi and uxi species. This review reports the main bioactive compounds identified in these species and discusses their therapeutic potential. Searches were performed in MEDLINE (Via Pubmed) and Web of Science. Thirty-one studies that described or evaluated the development of formulations aimed at the therapeutic use of the species were included. The findings suggest that species have the potential for the development of pharmaceutical formulations due to their therapeutic properties. However, further studies are required to assess safety and efficacy of these products. Therefore, it is suggested that new research studies propose strategies so that technological development is based on awareness and preservation of the biome.

A Review of Medicinal Plants and Phytochemicals for the Management of Gout

Gout, characterized by elevated uric acid levels, is a common inflammatory joint disease associated with pain, joint swelling, and bone erosion. Existing treatments for gout often result in undesirable side effects, highlighting the need for new, safe, and cost-effective anti-gout drugs. Natural products, including medicinal plants and phytochemicals, have gained attention as potential sources of anti-gout compounds. In this review, we examined articles from 2000 to 2020 using PubMed and Google Scholar, focusing on the effectiveness of medicinal plants and phyto-chemicals in managing gout. Our findings identified 14 plants and nine phytochemicals with anti-gout properties. Notably, Teucrium polium, Prunus avium, Smilax riparia, Rhus coriaria, Foenic-ulum vulgare, Allium cepa, Camellia japonica, and Helianthus annuus exhibited the highest xa-thine oxidase inhibitory activity, attributed to their unique natural bioactive compounds such as phenolics, tannins, coumarins, terpenoids, and alkaloids. Herbal plants and their phytochemicals have demonstrated promising effects in reducing serum urate and inhibiting xanthine. This review aims to report recent studies on plants/phytochemicals derived from herbs beneficial in gout and their different mechanisms.

Effect of Bergenin on Human Gingival Fibroblast Response on Zirconia Implant Surfaces: An In Vitro Study

The poor quality of life associated with the loss of teeth can be improved by the placing of dental implants. However, successful implantation relies on integration with soft tissues or peri-implant inflammatory disease that can lead to the loss of the implant. Pharmacological agents, such as antibiotics and antiseptics, can be used as adjunct therapies to facilitate osseointegration; however, they can have a detrimental effect on cells, and resistance is an issue. Alternative treatments are needed. Hence, this study aimed to examine the safety profile of bergenin (at 2.5 μM and 5 μM), a traditional medicine, towards human gingival fibroblasts cultured on acid-etched zirconia implant surfaces. Cellular responses were analysed using SEM, resazurin assay, and scratch wound healing assay. Qualitative assessment was conducted for morphology (day 1) and attachment (early and delayed), and quantitative evaluation for proliferation (day 1, 3, 5 and 7), and migration (0 h, 6 h and 24 h). The concentrations of bergenin at 2.5 μM and 5 μM did not demonstrate a statistically significant effect with regard to any of the cellular responses (p > 0.05) tested. In conclusion, bergenin is non-cytotoxic and is potentially safe to be used as a local pharmacological agent for the management of peri-implant inflammatory diseases.

Bergenin Inhibits Tumor Growth and Overcomes Radioresistance by Targeting Aerobic Glycolysis

Hexokinase 2 (HK2), the first glycolytic rate-limiting enzyme, is closely correlated with the occurrence and progression of tumors. Effective therapeutic agents targeting HK2 are urgently needed. Bergenin has exhibited various pharmacological activities, such as antitumor properties. However, the effects of bergenin on the abnormal glucose metabolism of cancer cells are yet unclear. In this study, HK2 was overexpressed in OSCC tissues, and the depletion of HK2 inhibited the growth of OSCC cells in vitro and in vivo. Moreover, these results showed that the natural compound, bergenin, exerted a robust antitumor effect on OSCC cells. Bergenin inhibited cancer cell proliferation, suppressed glycolysis, and induced intrinsic apoptosis in OSCC cells by downregulating HK2. Notably, bergenin restored the antitumor efficacy of irradiation in the radioresistant OSCC cells. A mechanistic study revealed that bergenin upregulated the protein level of phosphatase and the tensin homolog deleted on chromosome 10 (PTEN) by enhancing the interaction between PTEN and ubiquitin-specific protease 13 (USP13) and stabilizing PTEN; this eventually inhibited AKT phosphorylation and HK2 expression. Bergenin was identified as a novel therapeutic agent against glycolysis to inhibit OSCC and overcome radioresistance. Targeting PTEN/AKT/HK2 signaling could be a promising option for clinical OSCC treatment.

Characterizations of microRNAs involved in the molecular mechanisms underlying the therapeutic effects of noni (Morinda citrifolia L.) fruit juice on hyperuricemia in mice

BACKGROUND

Hyperuricemia is generally defined as the high level of serum uric acid and is well known as an important risk factor for the development of various medical disorders. However, the medicinal treatment of hyperuricemia is frequently associated with multiple side-effects.

METHODS

The therapeutic effect of noni (Morinda citrifolia L.) fruit juice on hyperuricemia and the underlying molecular mechanisms were investigated in mouse model of hyperuricemia induced by potassium oxonate using biochemical and high-throughput RNA sequencing analyses.

RESULTS

The levels of serum uric acid (UA) and xanthine oxidase (XOD) in mice treated with noni fruit juice were significantly decreased, suggesting that the noni fruit juice could alleviate hyperuricemia by inhibiting the XOD activity and reducing the level of serum UA. The contents of both serum creatinine and blood urine nitrogen of the noni fruit juice group were significantly lower than those of the model group, suggesting that noni fruit juice promoted the excretion of UA without causing deleterious effect on the renal functions in mice. The differentially expressed microRNAs involved in the pathogenesis of hyperuricemia in mice were identified by RNA sequencing with their target genes further annotated based on both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases to explore the metabolic pathways and molecular mechanisms underlying the therapeutic effect on hyperuricemia by noni fruit juice.

CONCLUSION

Our study provided strong experimental evidence to support the further investigations of the potential application of noni fruit juice in the treatment of hyperuricemia.

Mechanistic insights of soluble uric acid-induced insulin resistance: Insulin signaling and beyond

Hyperuricemia is a metabolic disease caused by purine nucleotide metabolism disorder. The prevalence of hyperuricemia is increasing worldwide, with a growing trend in the younger populations. Although numerous studies have indicated that hyperuricemia may be an independent risk factor for insulin resistance, the causal relationship between the two is controversial. There are few reviews, however, focusing on the relationship between uric acid (UA) and insulin resistance from experimental studies. In this review, we summarized the experimental models related to soluble UA-induced insulin resistance in pancreas and peripheral tissues, including skeletal muscles, adipose tissue, liver, heart/cardiomyocytes, vascular endothelial cells and macrophages. In addition, we summarized the research advances about the key mechanism of UA-induced insulin resistance. Moreover, we attempt to identify novel targets for the treatment of hyperuricemia-related insulin resistance. Lastly, we hope that the present review will encourage further researches to solve the chicken-and-egg dilemma between UA and insulin resistance, and provide strategies for the pathogenesis and treatment of hyperuricemia related metabolic diseases.

Ferulic acid supplementation alleviates hyperuricemia in high-fructose/fat diet-fed rats via promoting uric acid excretion and mediating the gut microbiota

The prevalence of hyperuricemia (HUA) has been rising, and it is typically accompanied by renal injury and intestinal flora disorder, leading to a non-negligible health crisis. Ferulic acid (FA), as a familiar polyphenol, has been proven to exert anti-hyperuricemic properties via inhibiting uric acid (UA) synthesis; however, the detailed underlying mechanisms remain unclear. The aim of this study was to explore the regulatory effect of FA on UA excretion as a potential strategy for reducing UA levels, and the comorbidities of HUA. FA treatment downregulated the expression of urate absorption transporter genes and repressed the toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway in UA-stimulated HK-2 cells. To examine these effects in vivo, FA or allopurinol (positive control) was given to rats with HUA induced by a high-fructose/fat diet (HFFD) for 20 weeks. FA markedly decreased the serum UA, blood urea nitrogen, and creatinine levels. The expression of urate absorption transporters was downregulated, whereas the expression of secretion transporters was upregulated in the kidneys and intestines of FA-treated HUA rats. Additionally, FA mitigated renal oxidative stress, and suppressed the activation of the TLR4/NF-κB pathway and the downstream inflammatory response-related markers in the kidneys. Moreover, FA remodeled the composition of the gut microbiota, characterized by an increase in beneficial bacteria (e.g., Lactobacillus and Ruminococcus) and a decrease in pathogenic bacteria (e.g., Bacteroides). In conclusion, our study validated FA as an effective nutrient to ameliorate HFFD-induced HUA, suggesting its potential to mitigate the HUA-associated renal impairment and intestinal microbiota disturbance.

Naringenin Ameliorates Hyperuricemia by Regulating Renal Uric Acid Excretion via the PI3K/AKT Signaling Pathway and Renal Inflammation through the NF-κB Signaling Pathway

Hyperuricemia characterized by high serum levels of uric acid (UA, >6.8 mg/dL) is regarded as a common chronic metabolic disease. When used as a food supplement, naringenin might have various pharmacological activities, including antioxidant, free-radical-scavenging, and inflammation-suppressing activities. However, the effects of naringenin on hyperuricemia and renal inflammation and the underlying mechanisms remain to be elucidated. Here, we comprehensively examined the effects of naringenin on hyperuricemia and the attenuation of renal impairment. Mice were injected with 250 mg/kg of potassium oxonate (PO) and given 5% fructose water to induce hyperuricemia. The pharmacological effects of naringenin (10 and 50 mg/kg) and benzbromarone (positive control group, 20 mg/kg) on hyperuricemic mice were evaluated in vivo. The disordered expression of urate transporters in HK-2 cells was stimulated by 8 mg/dL UA, which was used to determine the mechanisms underlying the effects of naringenin in vitro. Naringenin markedly reduced the serum UA level in a dose-dependent manner and improved renal dysfunction. Moreover, the increased elimination of UA in urine showed that the effects of naringenin were associated with the regulation of renal excretion. Further examination indicated that naringenin reduced the expression of GLUT9 by inhibiting the PI3K/AKT signaling pathway and reinforced the expression of ABCG2 by increasing the abundance of PDZK1 in vivo and in vitro. Furthermore, sirius red staining and western blotting indicated that naringenin plays a protective role in renal injury by suppressing increases in the levels of pro-inflammatory cytokines, including IL-6 and TNF-α, which contribute to the inhibition of the TLR4/NF-κB signaling pathway in vivo and in vitro. Naringenin supplementation might be a potential therapeutic strategy to ameliorate hyperuricemia by promoting UA excretion in the kidney and attenuating the inflammatory response by decreasing the release of inflammatory cytokines. This study shows that naringenin could be used as a functional food or dietary supplement for hyperuricemia prevention and treatment.

New insight into the management of renal excretion and hyperuricemia: Potential therapeutic strategies with natural bioactive compounds

Hyperuricemia is the result of increased production and/or underexcretion of uric acid. Hyperuricemia has been epidemiologically associated with multiple comorbidities, including metabolic syndrome, gout with long-term systemic inflammation, chronic kidney disease, urolithiasis, cardiovascular disease, hypertension, rheumatoid arthritis, dyslipidemia, diabetes/insulin resistance and increased oxidative stress. Dysregulation of xanthine oxidoreductase (XOD), the enzyme that catalyzes uric acid biosynthesis primarily in the liver, and urate transporters that reabsorb urate in the renal proximal tubules (URAT1, GLUT9, OAT4 and OAT10) and secrete urate (ABCG2, OAT1, OAT3, NPT1, and NPT4) in the renal tubules and intestine, is a major cause of hyperuricemia, along with variations in the genes encoding these proteins. The first-line therapeutic drugs used to lower serum uric acid levels include XOD inhibitors that limit uric acid biosynthesis and uricosurics that decrease urate reabsorption in the renal proximal tubules and increase urate excretion into the urine and intestine via urate transporters. However, long-term use of high doses of these drugs induces acute kidney disease, chronic kidney disease and liver toxicity. Therefore, there is an urgent need for new nephroprotective drugs with improved safety profiles and tolerance. The current systematic review summarizes the characteristics of major urate transporters, the mechanisms underlying the pathogenesis of hyperuricemia, and the regulation of uric acid biosynthesis and transport. Most importantly, this review highlights the potential mechanisms of action of some naturally occurring bioactive compounds with antihyperuricemic and nephroprotective potential isolated from various medicinal plants.

Clinical Potential of Himalayan Herb Bergenia ligulata: An Evidence-Based Study

Herbal products have been used in traditional systems of medicine and by ethnic healers for ages to treat various diseases. Currently, it is estimated that about 80% of people worldwide use herbal traditional medicines against various ailments, partly due to easy accessibility and low cost, and the lower side effects they pose. Bergenia ligulata, a herb ranging from the Himalayas to the foothills, including the north-eastern states of India, has traditionally been used as a remedy against various diseases, most prominently kidney stones. The medicinal properties of B. ligulata have been attributed to bergenin, its most potent bioactive component. Apart from bergenin, the other compounds available in B. ligulata are arbutin, gallic acid, protocatechuic acid, chlorogenic acid, syringic acid, catechin, ferulic acid, afzelechin, paashaanolactone, caryophyllene, 1,8-cineole, β-eudesmol, stigmasterol, β-sitosterol, parasorbic acid, 3-methyl-2-buten-1-ol, phytol, terpinen-4-ol, tannic acid, isovalaric acid, avicularin, quercetin, reynoutrin, and sitoinoside I. This review summarizes various medicinal properties of the herb, along with providing deep insight into its bioactive molecules and their potential roles in the amelioration of human ailments. Additionally, the possible mechanism(s) of action of the herb's anti-urolithiatic, antioxidative, antipyretic, anti-diabetic, anti-inflammatory and hepatoprotective properties are discussed. This comprehensive documentation will help researchers to better understand the medicinal uses of the herb. Further studies on B. ligulata can lead to the discovery of new drug(s) and therapeutics for various ailments.

Anserine beneficial effects in hyperuricemic rats by inhibiting XOD, regulating uric acid transporter and repairing hepatorenal injury

This study aims to investigate the anti-hyperuricemia effect and mechanism of anserine in hyperuricemic rats. Hyperuricemic rats were induced with a combination of 750 mg per kg bw d potassium oxazinate (PO) and 200 mg per kg bw d hypoxanthine for a week, and the rats were separately orally administered anserine (20, 40, 80 mg kg^-1) and allopurinol (10 mg kg^-1) for three weeks. The results show that the content of serum uric acid (SUA) decreased by approximately 40% and 60% after the intervention of anserine and allopurinol, respectively. The activity of superoxide dismutase (SOD) was increased and the levels of malondialdehyde (MDA), alkaline phosphatase (ALP) and alanine aminotransferase (ALT) were significantly decreased in the anserine groups. After the administration of anserine, the contents of blood urea nitrogen (BUN) and creatinine (Cr) were reduced in the kidney, and the levels of the proinflammatory cytokines IL-1β, IL-6β, TNF-α and TGF-β and inflammatory cell infiltration were reduced in both the liver and kidney. Moreover, the gene expressions of xanthine oxidase (XOD), renal urate transporter 1 (URAT1) and glucose transporter type 9 (GLUT9) were downregulated by anserine administration, and the gene expressions of ATP-binding cassette transporter G2 (ABCG2), organic anion transporter 1 (OAT1) and organic anion transporter 3 (OAT3) were upregulated at the same time. These findings suggest that hepatorenal injury was repaired by anserine, which further regulated the expression of hepatic XOD and renal URAT1, GLUT9, ABCG2, OAT1 and OAT3 to relieve hyperuricemia in rats.

CDER167, a dual inhibitor of URAT1 and GLUT9, is a novel and potent uricosuric candidate for the treatment of hyperuricemia

Urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) are important targets for the development of uric acid-lowering drugs. We previously showed that the flexible linkers of URAT1 inhibitors could enhance their potency. In this study we designed and synthesized CDER167, a novel RDEA3710 analogue, by introducing a linker (methylene) between the naphthalene and pyridine rings to increase flexibility, and characterized its pharmacological and pharmacokinetics properties in vitro and in vivo. We showed that CDER167 exerted dual-target inhibitory effects on both URAT1 and GLUT9: CDER167 concentration-dependently inhibited the uptake of [14C]-uric acid in URAT1-expressing HEK293 cells with an IC50 value of 2.08 ± 0.31 μM, which was similar to that of RDEA3170 (its IC50 value was 1.47 ± 0.23 μM). Using site-directed mutagenesis, we demonstrated that CDER167 might interact with URAT1 at S35 and F365. In GLUT9-expressing HEK293T cells, CDER167 concentration-dependently inhibited GLUT9 with an IC50 value of 91.55 ± 15.28 μM, whereas RDEA3170 at 100 μM had no effect on GLUT9. In potassium oxonate-induced hyperuricemic mice, oral administration of CDER167 (10 mg·kg-1 · d-1) for 7 days was more effective in lowering uric acid in blood and significantly promoted uric acid excretion in urine as compared with RDEA3170 (20 mg·kg-1 · d-1) administered. The animal experiment proved the safety of CDER167. In addition, CDER167 displayed better bioavailability than RDEA3170, better metabolic stability and no hERG toxicity at 100 μM. These results suggest that CDER167 deserves further investigation as a candidate antihyperuricemic drug targeting URAT1 and GLUT9.

Bergenin alleviates H2 O2 -induced oxidative stress and apoptosis in nucleus pulposus cells: Involvement of the PPAR-γ/NF-κB pathway

Bergenin is a C-glucoside of 4-O-methyl gallic acid with a variety of biological activities, such as antioxidant and anti-inflammatory. Herein, we investigated the involvement of bergenin in the protective effect against H₂ O₂ -induced oxidative stress and apoptosis in human nucleus pulposus cells (HNPCs) and the underlying mechanisms. HNPCs were cotreated with various concentrations of bergenin and 200 μM H₂ O₂ for 24 h. Cell viability was detected by Cell Counting Kit-8 and lactate dehydrogenase release assays. Reactive oxygen species (ROS) was evaluated utilizing 2',7'-dichlorofluorescein-diacetate. Superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) levels were measured to assess oxidative stress. Apoptosis was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling and caspase-3/7 activity assays. Expression of protein was determined by western blotting. Results indicated that treatment with bergenin significantly alleviated H₂ O₂ -induced viability reduction and ROS overproduction in HNPCs in a dose-dependent manner. Bergenin alleviated H₂ O₂ -induced oxidative stress in HNPCs by increased activity of superoxide dismutase and level of glutathione peroxidase. H₂ O₂ -induced apoptosis and activity of caspase-3/7 were also suppressed by bergenin treatment in HNPCs. Western blotting showed that H₂ O₂ -induced decrease in expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and increase in nuclear factor κB (NF-κB) were inhibited by bergenin. However, the inhibitory effect of bergenin on H₂ O₂ -induced viability reduction, oxidative stress and apoptosis were noticeably abrogated in PPAR-γ knockdown HNPCs. In conclusion, our results indicated that bergenin alleviates H₂ O₂ -induced oxidative stress and apoptosis in HNPCs by activating PPAR-γ and suppressing NF-κB pathway.

Ellagic Acid Exerts Beneficial Effects on Hyperuricemia by Inhibiting Xanthine Oxidase and NLRP3 Inflammasome Activation

Hyperuricemia is a metabolic disease caused by impaired uric acid (UA) metabolism. Ellagic acid (EA) is a natural small-molecule polyphenolic compound with known antioxidative and anti-inflammatory properties. Here, we evaluated the regulatory effects of EA on hyperuricemia and explored the underlying mechanisms. We found that EA is an effective xanthine oxidase (XOD) inhibitor (IC₅₀ = 165.6 μmol/L) and superoxide anion scavenger (IC₅₀ = 27.66 μmol/L). EA (5 and 10 μmol/L) treatment significantly and dose-dependently reduced UA levels in L-O2 cells; meanwhile, intraperitoneal EA administration (50 and 100 mg/kg) also significantly reduced serum XOD activity and UA levels in hyperuricemic mice and markedly improved their liver and kidney histopathology. EA treatment significantly reduced the degree of foot edema and inhibited the expression of NLPR3 pathway-related proteins in foot tissue of monosodium urate (MSU)-treated mice. The anti-inflammatory effect was also observed in lipopolysaccharide-stimulated RAW-264.7 cells. Furthermore, EA significantly inhibited the expressions of XOD and NLRP3 pathway-related proteins (TLR4, p-p65, caspase-1, TNF-α, and IL-18) in vitro and in vivo. Our results indicated that EA exerts ameliorative effects in experimental hyperuricemia and foot edema via regulating the NLRP3 signaling pathway and represents a promising therapeutic option for the management of hyperuricemia.

Bergenin - a biologically active scaffold: Nanotechnological perspectives

Bergenin, 4-O-methyl gallic acid glucoside, is a bioactive compound present in various plants belonging to different families. The present work compiles scattered information on pharmacology, structure activity relationship and nanotechnological aspects of bergenin, collected from various electronic databases such as Sci Finder, PubMed, Google scholar, etc. Bergenin has been reported to exhibit hepatoprotective, anti-inflammatory, anticancer, neuroprotective, antiviral and antimicrobial activities. Molecular docking studies have shown that isocoumarin pharmacophore of bergenin is essential for its bioactivities. Bergenin holds a great potential to be used as lead molecule and also as a therapeutic agent for development of more efficacious and safer semisynthetic derivatives. Nanotechnological concepts can be employed to overcome poor bioavailability of bergenin. Finally, it is concluded that bergenin can be emerged as clinically potential medicine in modern therapeutics.

mTORC1 promotes mineralization via p53 pathway

The objectives of our study were to investigate the roles of mTORC1 in odontoblast proliferation and mineralization and to determine the mechanism by which mTORC1 regulates odontoblast mineralization. In vitro, MDPC23 cells were treated with rapamycin (10 nmol/L) and transfected with a lentivirus for short hairpin (shRNA)-mediated silencing of the tuberous sclerosis complex (shTSC1) to inhibit and activate mTORC1, respectively. CCK8 assays, flow cytometry, Alizarin red S staining, ALP staining, qRT-PCR, and western blot analysis were performed. TSC1-conditional knockout (DMP1-Cre⁺ ; TSC1^f/f , hereafter CKO) mice and littermate control (DMP1-Cre^- ; TSC1^f/f , hereafter WT) mice were generated. H&E staining, immunofluorescence, and micro-CT analysis were performed. Transcriptome sequencing analysis was used to screen the mechanism of this process. mTORC1 inactivation decreased the cell proliferation. The qRT-PCR and western blot results showed that mineralization-related genes and proteins were downregulated in mTORC1-inactivated cells. Moreover, mTORC1 overactivation promoted cell proliferation and mineralization-related gene and protein expression. In vivo, the micro-CT results showed that DV/TV and dentin thickness were higher in CKO mice than in controls and H&E staining showed the same results. Mineralization-related proteins expression was upregulated. Transcriptome sequencing analysis revealed that p53 pathway-associated genes were differentially expressed in TSC1-deficient cells. By inhibiting p53 alone or both mTORC1 and p53 with rapamycin and a p53 inhibitor, we elucidated that p53 acts downstream of mTORC1 and that mTORC1 thereby promotes odontoblast mineralization. Taken together, our findings demonstrate that the role of mTORC1 in odontoblast proliferation and mineralization, and confirm that mTORC1 upregulates odontoblast mineralization via the p53 pathway.

The Role of ABCG2 in the Pathogenesis of Primary Hyperuricemia and Gout-An Update

Urate homeostasis in humans is a complex and highly heritable process that involves i.e., metabolic urate biosynthesis, renal urate reabsorption, as well as renal and extrarenal urate excretion. Importantly, disturbances in urate excretion are a common cause of hyperuricemia and gout. The majority of urate is eliminated by glomerular filtration in the kidney followed by an, as yet, not fully elucidated interplay of multiple transporters involved in the reabsorption or excretion of urate in the succeeding segments of the nephron. In this context, genome-wide association studies and subsequent functional analyses have identified the ATP-binding cassette (ABC) transporter ABCG2 as an important urate transporter and have highlighted the role of single nucleotide polymorphisms (SNPs) in the pathogenesis of reduced cellular urate efflux, hyperuricemia, and early-onset gout. Recent publications also suggest that ABCG2 is particularly involved in intestinal urate elimination and thus may represent an interesting new target for pharmacotherapeutic intervention in hyperuricemia and gout. In this review, we specifically address the involvement of ABCG2 in renal and extrarenal urate elimination. In addition, we will shed light on newly identified polymorphisms in ABCG2 associated with early-onset gout.

The Efficacy and Mechanism of Chinese Herbal Medicines in Lowering Serum Uric Acid Levels: A Systematic Review

Background. Chinese herbal medicines are widely used to lower serum uric acid levels. However, no systemic review summarizes and evaluates their efficacies and the underlying mechanisms of action. Objectives. To evaluate the clinical and experimental evidences for the effectiveness and the potential mechanism of Chinese herbal medicines in lowering serum uric acid levels. Methods. Four electronic databases PubMed, Wed of Science, the Cochrane Library and Embase were used to search for Chinese herbal medicines for their effects in lowering serum uric acid levels, dated from 1 January 2009 to 19 August 2020. For clinical trials, randomized controlled trials (RCTs) were included; and for experimental studies, original articles were included. The methodological quality of RCTs was assessed according to the Cochrane criteria. For clinical trials, a meta-analysis of continuous variables was used to obtain pooled effects. For experimental studies, lists were used to summarize and integrate the mechanisms involved. Results. A total of 10 clinical trials and 184 experimental studies were included. Current data showed that Chinese herbal medicines have promising clinical efficacies in patients with elevated serum uric acid levels (SMD: −1.65, 95% CI: −3.09 to −0.22; p = 0.024). There was no significant difference in serum uric acid levels between Chinese herbal medicine treatments and Western medicine treatments (SMD: −0.13, 95% CI: −0.99 to 0.74; p = 0.772). Experimental studies revealed that the mechanistic signaling pathways involved in the serum uric acid lowering effects include uric acid synthesis, uric acid transport, inflammation, renal fibrosis and oxidative stress. Conclusions. The clinical studies indicate that Chinese herbal medicines lower serum uric acid levels. Further studies with sophisticated research design can further demonstrate the efficacy and safety of these Chinese herbal medicines in lowering serum uric acid levels and reveal a comprehensive picture of the underlying mechanisms of action.