Active fraction of Polyrhachis vicina (Rogers) inhibits osteoclastogenesis by targeting Trim38 mediated proteasomal degradation of TRAF6

BACKGROUND

Reactive Oxygen Species (ROS) is a key factor in the pathogenesis of osteoporosis (OP) primarily characterized by excessive osteoclast activity. Active fraction of Polyrhachis vicina Rogers (AFPR) exerts antioxidant effects and possesses extensive promising therapeutic effects in various conditions, however, its function in osteoclastogenesis and OP is unknown.

PURPOSE

The aim of this study is to elucidate the cellular and molecular mechanisms of AFPR in OP.

STUDY DESIGN AND METHODS

CCK8 assay was used to evaluate the cell viability under AFPR treatment. TRAcP staining, podosome belts staining and bone resorption were used to test the effect of AFPR on osteoclastogenesis. Immunofluorescence staining was used to observe the effect of AFPR on ROS production. si-RNA transfection, coimmunoprecipitation and Western-blot were used to clarify the underlying mechanisms. Further, an ovariectomy (OVX) -induced OP mice model was used to identify the effect of AFPR on bone loss using Micro-CT scanning and histological examination.

RESULTS

In the present study, AFPR inhibited osteoclast differentiation and bone resorption induced by nuclear factor-κB receptor activator (NF-κB) ligand (RANKL) in dose-/ time-dependent with no cytotoxicity. Meanwhile, AFPR decreased RANKL-mediated ROS levels and enhanced ROS scavenging enzymes. Mechanistically, AFPR promoted proteasomal degradation of TRAF6 by significantly upregulating its K48-linked ubiquitination, subsequently inhibiting NFATc1 activity. We further observed that tripartite motif protein 38 (TRIM38) could mediate the ubiquitination of TRAF6 in response to RANKL. Moreover, TRIM38 could negatively regulate the RANKL pathway by binding to TRAF6 and promoting K48-linked polyubiquitination. In addition, TRIM38 deficiency rescued the inhibition of AFPR on ROS and NFATc1 activity and osteoclastogenesis. In line with these results, AFPR reduced OP caused by OVX through ameliorating osteoclastogenesis.

CONCLUSION

AFPR alleviates ovariectomized-induced bone loss via suppressing ROS and NFATc1 by targeting Trim38 mediated proteasomal degradation of TRAF6. The research offers innovative perspectives on AFPR's suppressive impact in vivo OVX mouse model and in vitro, and clarifies the fundamental mechanism.

Active fraction of Polyrhachis vicina (Roger) alleviated cerebral ischemia/reperfusion injury by targeting SIRT3-mediated mitophagy and angiogenesis

BACKGROUND

Damaged mitophagy and impaired angiogenesis involve in the pathogenic development of ischemic stroke. Active fraction of Polyrhachis vicina (Roger) (AFPR) showed great potential on neurological disease with it's remarkable anti-inflammatory and anti-oxidative effects.

PURPOSE

This study designed to clarify the correlation between Pink1/Parkin-mediated mitophagy and angiogenesis after stroke, and to elucidate the role of SIRT3 in regulating mitophagy and angiogenesis, and to address the mechanism of AFPR on promoting mitophagy and angiogenesis in microvessels endothelium of ischemic brain.

STUDY DESIGN

A cerebral ischemia/reperfusion (CIR) rat model was developed by middle cerebral artery occlusion procedure. bEnd.3 cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic CIR process. Neurological function, mitophagy and angiogenesis related indicators were measured. SIRT3 siRNA and 3-MA were used to verify the interaction between SIRT3-mediated mitophagy and angiogenesis.

METHODS

CIR rats were orally treated with AFPR (8 and 4 g raw drug /kg) and Nimodipine (10.8 mg/kg) for 12 days to mimic the recovery phase post-stroke. The neurological function assessment, TTC staining, HE staining, TUNEL staining and Nissl staining were performed to assess neuroprotective effects of AFPR against CIR. Then CD31-labeled microvessel density in brain was visualized and quantified by immunofluorescence staining. Mitochondrial ultrastructure was assessed by transmission electron microscope scanning. Expressions of relative proteins,e.g. SIRT3, Pink1, Parkin, LC3-II, p62, VEGFA, involving in mitophagy and angiogenesis, were detected by Western blotting analysis. In vitro, bEnd.3 cells were cultured with AFPR or in combination of autophagy inhibitor 3-MA during the reoxygenation. Then cell viability, and LDH releasing were measured. Angiogenic indicators,such as migration and tube formation activity, VEGFA level were determined. To assess effects of AFPR on mitophagy, mitophagy-related proteins were detected, as well as the autophagosome engulfment and lysosome degradation of mitochondria. To address the role of SIRT3, deacetylation activity of SIRT3 was validated by detecting acetylated FOXO3A level with co-immunoprecipitation (Co-IP) assay. Pre-treatment of siRNA or combination use of 3-MA were used to verify the detailed mechanism.

RESULTS

AFPR remarkably reduced neurological scores and infarct size, alleviated neuron apoptosis in cortex, and increased Nissl density in hippocampus of CIR rats. In addition, AFPR significantly promoted angiogenesis by increasing microvessels density and VEGFA expressions, increased SIRT3 expression, and activated Pink1/Parkin mediated mitophagy. In bEnd.3 cells, the combination use of 3-MA and AFPR further demonstrated that AFPR might promote angiogenesis after OGD/R injury through activating Pink1/Parkin mediated mitophagy. Co-IP assay suggested AFPR reduced acetylated FOXO3A level. This might be correlated with an elevation of SIRT3 expression and it's deacetylation activity. SIRT3 siRNA pretreatment significantly abolished the activation of mitophagy through Pink1/Parkin axis, eventually inhibited angiogenesis.

CONCLUSION

AFPR promoted angiogenesis through activating mitophagy after cerebral ischemia reperfusion, which might partially involved in the amelioration of SIRT3-mediated regulation on Pink1/Parkin axis. Our study will shed new light on the role of SIRT3 in ischemic brain, especially in regulating mitophagy and angiogenesis after stroke.

The Active Fraction of Polyrhachis vicina Roger (AFPR) activates ERK to cause necroptosis in colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Polyrhachis vicina Roger (P. vicina), a traditional Chinese medicinal animal, has been used to treat rheumatoid arthritis, hepatitis, cancer, and other conditions. Due to its anti-inflammatory properties, our previous pharmacological investigations have demonstrated that it is effective against cancer, depression, and hyperuricemia. Nevertheless, the key active components and targets of P. vicina in cancers are still unexplored.

AIM OF THE STUDY

The study aimed to evaluate the pharmacological treatment mechanism of the active fraction of P. vicina (AFPR) in treating colorectal cancer (CRC) and to further reveal its active ingredients and key targets.

METHODS

To examine the inhibitory impact of AFPR on CRC growth, tumorigenesis assays, cck-8 assays, colony formation assays, and MMP detection were utilized. The primary components of AFPR were identified by GC-MS analysis. The network pharmacology, molecular docking, qRT-PCR, western blotting, CCK-8 assays, colony formation assay, Hoechst staining, Annexin V-FITC/PI double staining, and MMP detection were performed to pick out the active ingredients and potential key targets of AFPR. The function of Elaidic acid on necroptosis was investigated through siRNA interference and the utilization of inhibitors. Elaidic acid's effectiveness to suppress CRC growth in vivo was assessed using a tumorigenesis experiment.

RESULTS

Studies confirmed that AFPR prevented CRC from growing and evoked cell death. Elaidic acid was the main bioactive ingredient in AFPR that targeted ERK. Elaidic acid greatly affected the ability of SW116 cells to form colonies, produce MMP, and undergo necroptosis. Additionally, Elaidic acid promoted necroptosis predominantly by activating ERK/RIPK1/RIPK3/MLKL.

CONCLUSION

According to our findings, Elaidic acid is the main active component of AFPR, which induced necroptosis in CRC through the activation of ERK. It represents a promising alternative therapeutic option for CRC. This work provided experimental support for the therapeutic application of P. vicina Roger in the treatment of CRC.

Evaluation of anti-hyperuricemic effects of Alocasia longiloba Miq. (Keladi Candik) extracts in potassium oxonate induced rat model

Hyperuricemia has become a significant public-health concern in recent years, and the available treatments have been reported to have an adverse side effect on patients. Alocasia longiloba has been used traditionally in Malaysia for treating gout, inflammation, and wounds. However, the plant has not been investigated for its effects on hyperuricemia. This study investigated the anti-hyperuricemic and anti-inflammatory effects of A. longiloba extracts in hyperuricemic rats induced by potassium oxonate (250 mg/kg body weight). Rats were given A. longiloba extracts or a standard drug for two-week, and blood and tissue samples were collected for analysis. Results show that A. longiloba extracts significantly reduced serum uric acid levels in hyperuricemic rats and inhibited xanthine oxidase (XOD) activity in the liver and kidney, which could be the mechanism underlying the urate-lowering effects. The extracts also significantly (p < 0.05) reduced the levels of proinflammatory cytokines (IL-18 and IL-1β) in serum samples and had hepatoprotective and nephroprotective effects in hyperuricemic rats. The study supports the use of A. longiloba as a complementary therapy for treating hyperuricemia.

Integrating Network Pharmacology, Molecular Docking and Pharmacological Evaluation for Exploring the Polyrhachis vicina Rogers in Ameliorating Depression

Purpose

To investigate the mechanisms of antidepressant action of active fraction of Polyrhachis vicina Rogers (AFPR) through network pharmacology, molecular docking and experimental validation.

Methods

GC-MS was used to predict chemical compounds, corresponding databases were used to predict chemical compound targets and depression targets, Cytoscape software was used to construct and analyze the protein interaction network map, DAVID database was used to analyze gene ontology (GO) and KEGG signaling pathway, and AGFR software was used to perform molecular docking. Subsequently, the underlying action mechanisms of AFPR on depression predicted by network pharmacology analyses were experimentally validated in a CORT-induced depression model in vitro and in vivo.

Results

A total of 52 potential targets of AFPR on antidepressant were obtained. GO is mainly related to chemical synaptic transmission, signal transduction and others. KEGG signaling pathways are mainly related to cAMP signaling pathway and C-type lectin receptor signaling pathway. The experiment results showed that AFPR significantly increased the expression of PRKACA, CREB and BDNF in mouse brain tissue and PC12 cells. Furthermore, after interfered of cAMP in PC12 cells, the decreased expression of PRKACA, CREB and BDNF was reversed by AFPR.

Conclusion

AFPR may exert antidepressant effects through multiple components, targets and pathways. Furthermore, it could improve neuroplasticity via the cAMP signaling pathway to improve depression-like symptoms.

Research Progress of Natural Active Substances with Uric-Acid-Reducing Activity

Hyperuricemia is a metabolic disease caused by the accumulation of uric acid in the body. Allopurinol, benzbromarone, and febuxostat, which are available in the market, have reduced the circulating urate levels; however, they exhibit serious side effects. Therefore, it is reasonable to develop a new active antihyperuricemia drug with few side effects. With the deepening of research, numerous kinds of literature have shown that natural active substances are effective in the treatment of hyperuricemia with a variety of sources and few side effects, which have become the focus of research in recent years. This review focuses on natural active substances with uric-acid-reducing activity and discusses their pharmacological effects. More specifically, the bioactive compounds of natural active substances are divided into five categories: natural extracts, monomer compounds extracted from plants, natural protease hydrolysates, peptides, and probiotic bacteria. In addition, the mechanisms by which these bioactive compounds exhibit hypouricemic effects can be divided into four classes: inhibition of key enzyme activities, promotion of uric acid excretion and inhibition of reabsorption in the kidney, promotion of decomposing uric acid precursors, and promotion of decomposing uric acid. Overall, this current and comprehensive review examines the role of natural active substances in the treatment of hyperuricemia.

A flavonoid-rich fraction of Monolluma quadrangula inhibits xanthine oxidase and ameliorates potassium oxonate-induced hyperuricemia in rats

Hyperuricemia represents a risk factor for the progression of chronic kidney disease. Oxidative stress and inflammation are implicated in the mechanisms underlying hyperuricemia-mediated kidney injury. Monolluma quadrangula possesses several beneficial effects; however, its effect on hyperuricemia has not been investigated. This study evaluated the renoprotective and xanthine oxidase (XO) inhibitory activity of M. quadrangula in hyperuricemic rats. Phytochemical investigation revealed the presence of six known flavonoid isolated for the first time from this species. The rats received M. quadrangula extract (MQE) and potassium oxonate (PO) for 7 days. In vitro assays showed the radical scavenging and XO inhibitory activities of MQE, and in silico molecular docking revealed the inhibitory activity of the isolated flavonoids towards XO. Hyperuricemic rats showed elevated serum uric acid, creatinine, urea, and XO activity, and renal pro-inflammatory cytokines, MDA and NO, and decreased GSH, SOD, and catalase. MQE ameliorated serum uric acid, urea, creatinine, and XO activity, and renal pro-inflammatory cytokines. In addition, MQE attenuated renal oxidative stress, enhanced antioxidants, downregulated URAT-1, and GLUT-9 and upregulated OAT-1 in PO-induced rats. In conclusion, M. quadrangula attenuated hyperuricemia and kidney impairment by suppressing XO activity, oxidative stress and inflammation, and modulating urate transporters.

Naringenin Prevents Inflammation, Apoptosis, and DNA Damage in Potassium Oxonate-Induced Hyperuricemia in Rat Liver Tissue: Roles of Cytochrome C, NF-κB, Caspase-3, and 8-Hydroxydeoxyguanosine

Background: Hyperuricemia (HU) is a metabolic disease characterized by high uric acid levels in the blood. HU is a risk factor for diabetes, cardiovascular complications, metabolic syndrome, and chronic kidney disease. Purpose: The present study was performed to determine the effect of experimental HU on xanthine oxidase (XO), tumor necrosis factor-alpha (TNF-α), nuclear factor-kappa B (NF-κB), interleukin-17 (IL-17), cytochrome C, glutathione peroxidase (GPx), caspase-3, and 8-hydroxydeoxyguanosine (8-OHdG) levels in liver tissues of rats. Study Design: Thirty-five, male, Wistar albino-type rats were used for this study. Experimental groups were formed as follows: Group 1: control group; Group 2: potassium oxonate (PO) group; group 3: PO+NAR (naringenin; 2 weeks) group; and Group 4: PO (2 weeks)+NAR (2 weeks) group (total of 4 weeks). Methods: The first group was not given anything other than normal rat food and drinking water. In the second group, a 250 mg/kg intraperitoneal dose of PO was administered for 2 weeks. In the third group, 250 mg/kg intraperitoneal PO (application for 2 weeks) and 100 mg/kg NAR intraperitoneally 1 hr after each application were administered. In the fourth group, intraperitoneal PO administration was applied for 2 weeks, followed by intraperitoneal administration of NAR for 2 weeks (4 weeks in total). At the end of the experimental period, XO, TNF-α, NF-κB, IL-17, cytochrome C, GPx, caspase-3, and 8-OHdG levels were determined in liver tissues. Results: HU increased XO, TNF-α, NF-κB, IL-17, cytochrome C, caspase-3, and 8-OHdG levels in liver tissues. However, both 2 and 4 weeks of NAR supplementation decreased these values, and also NAR supplementation led to an increase in GPx levels in tissues. Conclusions: The results of the study show that increased inflammation, apoptosis, and DNA damage in experimental HU can be prevented by administration of NAR due to inhibition of cytochrome C, NF-κB, caspase-3, and 8-OHdG.

Polyrhachis vicina Roger Alleviates Memory Impairment in a Rat Model of Alzheimer's Disease Through the EGR1/BACE1/APP Axis

Memory deficits and loss are the earliest and most prominent features of Alzheimer's disease (AD). This study was aimed to clarify the mechanistic basis of an active fraction of Polyrhachis vicina Roger (AFPR) on the memory abilities of AD rat models, which involves early growth response 1 (EGR1) expression and β-secretase 1 (BACE1)-mediated deposition of amyloid β peptide (Aβ). An AD rat model was developed by Aβ25-35, which was further treated with AFPR alone or in combination with lentiviral EGR1. The Morris water maze test and HE and Fluoro-Jade C staining were adopted to observe the memory behaviors, hippocampus neuron morphology, and Aβ deposition. Aβ25-35-induced SK-N-SH and HT22 neurons were subjected to AFPR for in vitro experiments on neuronal viability and apoptosis. AFPR improved the impaired memory function, preserved the neuron structure, and suppressed Aβ deposition in AD rat models. Further, the expression of APP pathway-related proteins was downregulated by AFPR in both rat and cellular models. Moreover, AFPR inhibited the Aβ25-35-induced neuronal apoptosis. AFPR suppressed the expression of EGR1, downregulated the BACE1 expression via impeding the binding of EGR1 to the BACE1 promoter, and thus blocked the activation of the APP signaling, ultimately protecting neurons. Notably, the aforementioned effects of AFPR were in a concentration-dependent manner; among three doses, 3.65, 15.6, and 30 mg/(kg·d), high-dose AFPR exhibited the most appreciable effects. In conclusion, AFPR inhibited the BACE1 expression by repressing the binding of EGR1 to the promoter of BACE1, thereby suppressing the Aβ deposition and improving the memory function of AD rats.

Synergistic Impacts of Alpinia oxyphylla Seed Extract and Allopurinol against Experimental Hyperuricemia

In traditional medicine, Alpinia oxyphylla Miquel seed has been used to treat gout and hyperuricemia-related symptoms by enhancing kidney functions. Allopurinol is the most commonly used drug to treat hyperuricemia; however, the drug has many adverse effects. Combining allopurinol with another compound could reduce the need for high doses and result in improved safety. We investigated the possible synergistic effects of Alpinia oxyphylla seed extract (AE) and allopurinol in decreasing urate concentrations in rats with potassium oxonate-induced hyperuricemia. This study evaluated the effects of allopurinol combined with AE on levels of serum urate, blood urea nitrogen (BUN), and creatinine in a hyperuricemic rat model. The effects of allopurinol plus AE on xanthine oxidase (XOD) activity and urate uptake were measured. The concomitant administration of allopurinol and AE normalized serum urate and reduced BUN and creatinine. The attenuation of hyperuricemia-induced impaired kidney function was related to downregulation of renal urate transporter 1 and upregulation of renal organic anion transporter 1, with inhibition of serum and hepatic XOD activities. The antihyperuricemic effects of allopurinol were enhanced when combined with AE. These results suggested that the combined use of allopurinol and AE may have clinical efficacy in treating hyperuricemia.

Hypouricemic Effect of Submerged Culture of Ganoderma lucidum in Potassium Oxonate-Induced Hyperuricemic Rats

Hyperuricemia is a disease caused by a high level of uric acid in the blood. It is an important factor for gout and may be linked to renal and hepatic failure. The objective of this study was to investigate the hypouricemic effects of submerged culture of Ganoderma lucidum. The lyophilized powder of mycelium (GM) and extracellular polysaccharides (GP) of the G. lucidum submerged culture were prepared. The contents of hypouricemic components, including phenolics and flavonoids, in GM (34.33 ± 0.41 mg/g and 0.32 ± 0.01 mg/g) were higher than that in GP (20.52 ± 1.49 mg/g and not detected). The hypouricemic effect of GM and GP was evaluated in potassium oxonate (PO)-injected rats. The average food intake (23.3 ± 1.2 g/day) and body weight (355.7 ± 28.0 g) were decreased, and the serum level of uric acid (5.56 ± 0.41 mg/dL) was increased in PO-injected rats. However, allopurinol (10 mg/kg b.w.) or GM treatment (200 or 400 mg/kg b.w) improved food intake (26.3 ± 2.7 g/day) and reduced the level of uric acid (4.45 ± 0.46 mg/dL). In parallel, the activity of hepatic xanthine oxidase (XOD) was downregulated from 841.29 ± 299.58 μU/mg protein to 540.80 ± 199.20 μU/mg protein. Moreover, GM and GP (200 or 400 mg/kg b.w) alleviated the level of blood urea nitrogen (BUN) from 30.49 ± 4.71 to 21.16 ± 4.25 mg/dL. GP treatment also diminished the level of alanine transaminase (ALT) from 52.63 ± 18.82 to 27.35 ±6.82 U/L. These results clearly demonstrated the hypouricemic effect of submerged G. lucidum culture and their potential against hyperuricemia-associated renal and hepatic damage. GM was more potent to alleviate hyperuricemia, and GP was more potent to improve renal and hepatic function.

Characterization, Antioxidant Activities, and Pancreatic Lipase Inhibitory Effect of Extract From the Edible Insect Polyrhachis vicina

Oxidative stress and obesity are critical risk factors for metabolic syndrome. The consumption of functional food ingredients can a viable strategy to alleviate oxidative stress and obesity. In this study, the hydro-ethanolic extract of the edible insect Polyrhachis vicina was prepared and its bioactive components were characterized. The total polyphenol contents, total flavonoid contents, antioxidant and pancreatic lipase (PL) inhibitory activities of the extract were determined in vitro. In total, 60 bioactive components were tentatively identified in the P. vicina extract. Polyphenols and fatty acids were further quantified using LC-MS and GC-MS, respectively. P. vicina extract possessed excellent antioxidant and PL inhibition activities. Salicylic acid, gallic acid, liquiritigenin, and naringenin, which were the major polyphenols in the P. vicina extract, interacted with PL through hydrogen bonding, hydrophilic or hydrophobic and pi-cation interactions. Thus, P. vicina extract can be used as a nutraceutical to alleviate oxidative stress-induced disease and manage obesity.

Design, synthesis, and biological evaluation of N-(3-cyano-1H-indol-5/6-yl)-6-oxo-1,6-dihydropyrimidine-4-carboxamides and 5-(6-oxo-1,6-dihydropyrimidin-2-yl)-1H-indole-3-carbonitriles as novel xanthine oxidase inhibitors

Xanthine oxidase (XO) has been an important target for the treatment of hyperuricemia and gout. The analysis of potential interactions of pyrimidinone and 3-cyano indole pharmacophores present in the corresponding reported XO inhibitors with parts of the XO active pocket indicated that they both can be used as effective fragments for the fragment-based design of nonpurine XO inhibitors. In this paper, we adopted the fragment-based drug design strategy to link the two fragments with an amide bond to design the type 1 compounds 13a-13w,14c, 14d, 14f, 14g, 14j, 14k, and 15g. Compound 13g displayed an evident XO inhibitory potency (IC₅₀ = 0.16 μM), which was 52.3-fold higher than that of allopurinol (IC₅₀ = 8.37 μM). For comparison, type 2 compounds 5-(6-oxo-1,6-dihydropyrimidin-2-yl)-1H-indole-3-carbonitriles (25c-25g) were also designed by linking the two fragments with a single bond directly. The results showed that compound 25c from the latter series displayed the best inhibitory potency (IC₅₀ = 0.085 μM), and it was 98.5-fold stronger than that of allopurinol (IC₅₀ = 8.37 μM). These results suggested that amide and single bonds were applicable for linking the two fragments together to obtain potent nonpurine XO inhibitors. The structure-activity relationship results revealed that hydrophobic groups at N-atom of the indole moiety were indispensable for the improvement of the inhibitory potency in vitro against XO. In addition, enzyme kinetics studies suggested that compounds 13g and 25c, as the most promising XO inhibitors for the two types of target compounds, acted as mixed-type inhibitors for XO. Moreover, molecular modeling studies suggested that the pyrimidinone and indole moieties of the target compounds could interact well with key amino acid residues in the active pocket of XO. Furthermore, in vivo hypouricemic effect demonstrated that compounds 13g and 25c could effectively reduce serum uric acid levels at an oral dose of 10 mg/kg. Therefore, compounds 13g and 25c could be potential and efficacious agents for the treatment of hyperuricemia and gout.

Drug Transporters in the Kidney: Perspectives on Species Differences, Disease Status, and Molecular Docking

The kidneys are a pair of important organs that excretes endogenous waste and exogenous biological agents from the body. Numerous transporters are involved in the excretion process. The levels of these transporters could affect the pharmacokinetics of many drugs, such as organic anion drugs, organic cationic drugs, and peptide drugs. Eleven drug transporters in the kidney (OAT1, OAT3, OATP4C1, OCT2, MDR1, BCRP, MATE1, MATE2-K, OAT4, MRP2, and MRP4) have become necessary research items in the development of innovative drugs. However, the levels of these transporters vary between different species, sex-genders, ages, and disease statuses, which may lead to different pharmacokinetics of drugs. Here, we review the differences of the important transports in the mentioned conditions, in order to help clinicians to improve clinical prescriptions for patients. To predict drug-drug interactions (DDIs) caused by renal drug transporters, the molecular docking method is used for rapid screening of substrates or inhibitors of the drug transporters. Here, we review a large number of natural products that represent potential substrates and/or inhibitors of transporters by the molecular docking method.

A brief review of urate transporter 1 (URAT1) inhibitors for the treatment of hyperuricemia and gout: Current therapeutic options and potential applications

Hyperuricemia is a common metabolic condition, cause by increased levels of serum urate (SUA). Reduced excretion of uric acid is reported as the key factor of primary hyperuricemia, accounting for approximately 90% of the cases. Urate transporter 1 (URAT1) is a major protein involved in uric acid reabsorption (about 90%). Therefore, URAT1 inhibitors are considered to be a highly effective and promising class of uricosuric agents for treating hyperuricemia. This review summarizes the development of URAT1 inhibitors for the treatment of hyperuricemia, including approved URAT1 inhibitors, URAT1 inhibitors under development in clinical trials, substances with URAT1 inhibitory effects from derivatives and natural products, and conventional drugs with new uses. This review provides new ideas regarding research on URAT1 inhibitors by introducing the structure, properties, and side effects of chemical drugs, as well as the sources and categories of natural drugs. We also discuss new mechanisms of classic drugs, which may provide guidance to many practicing clinicians. The research and discovery of new inhibitors remain in full swing, and tremendous developments are expected in the field.

Natural Products and Extracts as Xantine Oxidase Inhibitors - A Hope for Gout Disease?

Xanthine oxidase (EC 1.17.3.2) (XO) is one of the main enzymatic sources that create reactive oxygen species (ROS) in the living system. It is a dehydrogenase enzyme that performs electron transfer to nicotinamide adenine dinucleotide (NAD+), while oxidizing hypoxanthin, which is an intermediate compound in purine catabolism, first to xanthine and then to uric acid. XO turns into an oxidant enzyme that oxidizes thiol groups under certain stress conditions in the tissue. The last metabolic step, in which hypoxanthin turns into uric acid, is catalyzed by XO. Uric acid, considered a waste product, can cause kidney stones and gouty-type arthritis as it is crystallized, when present in high concentrations. Thus, XO inhibitors are one of the drug classes used against gout, a purine metabolism disease that causes urate crystal storage in the joint and its surroundings caused by hyperuricemia. Urate-lowering therapy includes XO inhibitors that reduce uric acid production as well as uricosuric drugs that increase urea excretion. Current drugs that obstruct uric acid synthesis through XO inhibition are allopurinol, febuxostat, and uricase. However, since the side effects, safety and tolerability problems of some current gout medications still exist, intensive research is ongoing to look for new, effective, and safer XO inhibitors of natural or synthetic origins for the treatment of the disease. In the present review, we aimed to assess in detail XO inhibitory capacities of pure natural compounds along with the extracts from plants and other natural sources via screening Pubmed, Web of Science (WoS), Scopus, and Google Academic. The data pointed out to the fact that natural products, particularly phenolics such as flavonoids (quercetin, apigenin, and scutellarein), tannins (agrimoniin and ellagitannin), chalcones (melanoxethin), triterpenes (ginsenoside Rd and ursolic acid), stilbenes (resveratrol and piceatannol), alkaloids (berberin and palmatin) have a great potential for new XO inhibitors capable of use against gout disease. In addition, not only plants but other biological sources such as microfungi, macrofungi, lichens, insects (silk worms, ants, etc) seem to be the promising sources of novel XO inhibitors.

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

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.

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.

Medicinal Plants as a Drug Alternative Source for the Antigout Therapy in Morocco

BACKGROUND

The gout is a metabolic disease that is associated with a high level of uric acid in the blood. This disease is treated with some medications that aim to reduce serum urate levels. However, the use of various medicines leads to the appearance of some side effects, hence the importance of using other treatments based on natural resources.

OBJECTIVE

This study presents some medical treatments, their side effects, and some plants that are used for gout management in Morocco in the aim to valorize them.

METHODS

We have been consulting various English publications in PubMed, Web of Science, and ScienceDirect published between 1991 and 2019 using the following keywords "drugs," "gout," "Morocco," "medicinal plants," "in vitro," and "in vivo" terms. Then, we have classified the medicines, according to their action mechanisms, and we have cited some species that were reported in Moroccan pharmacopeia as antigout.

RESULTS

Three methods of the gout medical management were cited in this work: xanthine oxidase inhibitors, uric acid excretion enhancer, and uricase recombinant. However, it was found that these treatments had various side effects. We have described 23 species, and some of them showed experimentally an antigout effect by blocking the "xanthine oxidase" enzyme. These plants belong to 11 families. Lamiaceae represents the most dominant family with six species followed by Asteraceae with two species. Colchicine isolated from Colchicum autumnale is the most known compound for its efficiency towards gout.

CONCLUSION

This work summarized different treatments particularly medicinal plants that are used in Morocco to treat gout disease by blocking uric acid secretion. However, several studies are needed to valorize these antigout natural sources.

Luteolin Attenuates Glycerol-Induced Acute Renal Failure and Cardiac Complications Through Modulation of Kim-1/NF-κB/Nrf2 Signaling Pathways

Acute renal failure (ARF) has been documented as a life-threatening disease with high morbidity and mortality. We investigated the protective effect of Luteolin against ARF. In this study, forty-male Wistar albino rats were randomly divided into four groups (n = 10). Group A received normal saline. Group B received glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Groups C and D were pretreated with Luteolin 100 and 200 mg/kg for 7 days, and thereafter administered Glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Administration of glycerol significantly increased systolic blood pressure, diastolic blood pressure and mean arterial pressure. Renal protein carbonyl and xanthine oxidase increased significantly while significant reduction in the activity of renal glutathione peroxidase, glutathione S-transferase and glutathione reductase was observed in the glycerol intoxicated rats. Furthermore, administration of glycerol led to significant increases in serum creatinine and blood urea nitrogen together with reduction in nitric oxide (NO) bioavailability. Immunohistochemistry revealed that glycerol intoxication enhanced expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin (CTnI). However, Luteolin pretreatment normalized blood pressure, reduced markers of oxidative stress, renal damage, and improved NO bioavailability. Luteolin also downregulated the expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin. Together, Luteolin might open a novel therapeutic window for the treatment of acute renal failure and cardiac complication.

The Time-Feature of Uric Acid Excretion in Hyperuricemia Mice Induced by Potassium Oxonate and Adenine

Hyperuricemia is an important risk factor of chronic kidney disease, metabolic syndrome and cardiovascular disease. We aimed to assess the time-feature relationship of hyperuricemia mouse model on uric acid excretion and renal function. A hyperuricemia mouse model was established by potassium oxonate (PO) and adenine for 21 days. Ultra Performance Liquid Chromatography was used to determine plasma uric acid level. Hematoxylin-eosin staining was applied to observe kidney pathological changes, and Western blot was used to detect renal urate transporters’ expression. In hyperuricemia mice, plasma uric acid level increased significantly from the 3rd day, and tended to be stable from the 7th day, and the clearance rate of uric acid decreased greatly from the 3rd day. Further study found that the renal organ of hyperuricemia mice showed slight damage from the 3rd day, and significantly deteriorated renal function from the 10th day. In addition, the expression levels of GLUT9 and URAT1 were upregulated from the 3rd day, while ABCG2 and OAT1 were downregulated from the 3rd day, and NPT1 were downregulated from the 7th day in hyperuricemia mice kidney. This paper presents a method suitable for experimental hyperuricemia mouse model, and shows the time-feature of each index in a hyperuricemia mice model.

Active fraction of Polyrhachis vicina Rogers (AFPR) suppressed breast cancer growth and progression via regulating EGR1/lncRNA-NKILA/NF-κB axis

Breast cancer (BC) is a major contributor of cancer-associated mortality in women. It is essential to find new therapeutic targets and drugs. Polyrhachis vicina Rogers is one of the Traditional Chinese Medicine (TCM). Our previous studies have shown an active fraction of Polyrhachis vicina Rogers (AFPR) has significant anti-inflammatory activity, suggesting its anti-cancer effect. Here, we aimed to explore the inhibitory effects of AFPR on BC and reveal its mechanism. The effects of AFPR on BC were examined by cell proliferation assay, wound healing assay, invasion assay and xenograft assay. Microarray sequencing, qRT-PCR, Western blot, chromatin immunoprecipitation assay and luciferase reporter assay were performed to investigate the regulation of AFPR on related genes and underlying mechanisms. As a result, AFPR suppressed BC cell growth, migration and invasion and inhibited tumor growth. LncRNA NKILA was most prominently upregulated in AFPR-treated MCF7 cells. AFPR inactivated NF-κB signaling pathway via regulating NKILA. Furthermore, AFPR regulated the expression of NKILA by inhibiting its transcript suppressor EGR1. This study firstly indicated that AFPR was a potential inhibitor of BC development via regulating EGR1/NKILA/NF-κB axis.

Mouse models for human hyperuricaemia: a critical review

Hyperuricaemia (increased serum urate concentration) occurs mainly in higher primates, including in humans, because of inactivation of the gene encoding uricase during primate evolution. Individuals with hyperuricaemia might develop gout - a painful inflammatory arthritis caused by monosodium urate crystal deposition in articular structures. Hyperuricaemia is also associated with common chronic diseases, including hypertension, chronic kidney disease, type 2 diabetes and cardiovascular disease. Many mouse models have been developed to investigate the causal mechanisms for hyperuricaemia. These models are highly diverse and can be divided into two broad categories: mice with genetic modifications (genetically induced models) and mice exposed to certain environmental factors (environmentally induced models; for example, pharmaceutical or dietary induction). This Review provides an overview of the mouse models of hyperuricaemia and the relevance of these models to human hyperuricaemia, with an emphasis on those models generated through genetic modifications. The challenges in developing and comparing mouse models of hyperuricaemia and future research directions are also outlined.