Development of novel NLRP3-XOD dual inhibitors for the treatment of gout

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

ETHNOPHARMACOLOGICAL RELEVANCE

DaiTongXiao (DTX) is a traditional Chinese Dai folk formulation utilized for gouty arthritis treatment, with substantial evidence supporting its anti-inflammatory properties. The NLRP3 inflammasome disorder is tightly linked to the development of many inflammatory diseases.

AIM OF THE STUDY

To elucidate the therapeutic efficacy of DTX in gouty arthritis and reveal its potential underlying mechanism.

MATERIALS AND METHODS

The primary active constituents in DTX were determined through ultraviolet spectrophotometry and gas chromatography. Rats underwent induction with monosodium urate (MSU), followed by treatment of J774A.1 cells with adenosine triphosphate (ATP) activation and lipopolysaccharide (LPS) induction and the subsequent culture in Dulbecco's modified Eagle's medium. The degree of foot joint swelling in rats was assessed, and ankle joints were evaluated through H&E staining. Enzyme-linked immunosorbent assay was performed to measure the levels of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in both serum and cells. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to determine the relative mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 macrophages. The expression of NLRP3, ASC, Caspase-1, and NF-κB was examined by western blotting.

RESULTS

DTX could alleviate MSU-induced joint swelling in rats, as evidenced by a reduction in joint inflammation. Moreover, DTX effectively enhanced the survival rate of J774A.1 cells following LPS induction and ATP activation. Furthermore, DTX significantly reduced IL-1β, IL-6, IL-8, and TNF-α levels in both cell culture medium and rat serum. RT-PCR results revealed that DTX notably downregulated the mRNA expression levels of NLRP3, ASC, Caspase-1, and NF-κB in J774A.1 cells. Additionally, DTX downregulated NLRP3, ASC, NF-κB, and Caspase-1 expression in the joint tissue.

CONCLUSIONS

DTX exerts a significant anti-gouty arthritis effect, with its mechanism being tightly linked to the NLRP3 inflammatory signaling pathway. This pathway may be modulated by inhibiting IL-1β differentiation and maturation by downregulating NLRP3, ASC, Caspase-1, and NF-κB protein expression. This, in turn, leads to a reduction in the release of IL-6, IL-8, and TNF-α, ultimately impeding gouty arthritis progression.

Virtual screening and structure optimization of xanthine oxidase inhibitory peptides from whole protein sequences of Pacific white shrimp via molecular docking

Xanthine oxidase (XO) inhibitory peptides are safer than conventional pharmacological therapy in relieving hyperuricemia. However, traditional enzymatic hydrolysis, separation, and purification techniques for bio-active peptide preparation are time-consuming, inefficient, and labor-intensive. In this study, molecular docking and BLAST were used to virtually screen XO inhibitory peptides from whole protein sequences of Pacific white shrimp according to the bio-active peptides database, and the structure of peptides was optimized based on the structure-effective relationship. Seven new XO inhibitory peptides were virtual screened rapidly from Pacific white shrimp, and YNITGW (IC50 = 9.78 ± 0.13 mM) showed the strongest activity. The results of YNITGW optimization showed that the insertion of Trp residue in the middle position of peptides could effectively enhance the activity. This study revealed that screening and optimizing peptides by molecular docking were a novel and feasible method to obtain bio-active peptides.

Celebrating Versatility: Febuxostat's Multifaceted Therapeutic Application

Febuxostat, initially developed as a xanthine oxidase inhibitor to address hyperuricemia in gout patients, has evolved into a versatile therapeutic agent with multifaceted applications. This review provides a comprehensive overview of febuxostat's mechanism of action, its effectiveness in gout management, its cardiovascular safety profile, renal and hepatic effects, musculoskeletal applications, safety considerations, and emerging research prospects. Febuxostat's primary mechanism involves selective inhibition of xanthine oxidase, resulting in reduced uric acid production. Its pharmacokinetics require personalized dosing strategies based on individual characteristics. In gout management, febuxostat offers a compelling alternative, effectively lowering uric acid levels, relieving symptoms, and supporting long-term control, especially for patients intolerant to allopurinol. Recent studies have demonstrated its cardiovascular safety, and it exhibits minimal hepatotoxicity, making it suitable for those with liver comorbidities. Febuxostat's potential nephroprotective effects and kidney stone prevention properties are noteworthy, particularly for gout patients with renal concerns. Beyond gout, its anti-inflammatory properties hint at applications in musculoskeletal conditions and a broader spectrum of clinical contexts, including metabolic syndrome. Emerging research explores febuxostat's roles in cardiovascular health, neurological disorders, rheumatoid arthritis, and cancer therapy, driven by its anti-inflammatory and antioxidative properties. Future directions include personalized medicine, combination therapies, mechanistic insights, and ongoing long-term safety monitoring, collectively illuminating the promising landscape of febuxostat's multifaceted therapeutic potential.

Potential antioxidative and anti-hyperuricemic components in Rodgersia podophylla A. Gray revealed by bio-affinity ultrafiltration with SOD and XOD

Rodgersia podophylla A. Gray (R. podophylla) is a traditional Chinese medicine with various pharmacological effects. However, its antioxidant and anti-hyperuricemia components and mechanisms of action have not been explored yet. In this study, we first assessed the antioxidant potential of R. podophylla with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric ion reducing antioxidant power (FRAP) assays. The results suggested that the ethyl acetate (EA) fraction of R. podophylla not only exhibited the strongest DPPH, ABTS radical scavenging and ferric-reducing activities, but also possessed the highest total phenolic and total flavonoid contents among the five fractions. After that, the potential superoxide dismutase (SOD) and xanthine oxidase (XOD) ligands from the EA fraction were quickly screened and identified through the bio-affinity ultrafiltration liquid chromatography-mass spectrometry (UF-LC-MS). Accordingly, norbergenin, catechin, procyanidin B2, 4-O-galloylbergenin, 11-O-galloylbergenin, and gallic acid were considered to be potential SOD ligands, while gallic acid, 11-O-galloylbergenin, catechin, bergenin, and procyanidin B2 were recognized as potential XOD ligands, respectively. Moreover, these six ligands effectively interacted with SOD in molecular docking simulation, with binding energies (BEs) ranging from -6.85 to -4.67 kcal/mol, and the inhibition constants (Ki) from 9.51 to 379.44 μM, which were better than the positive controls. Particularly, catechin exhibited a robust binding affinity towards XOD, with a BE value of -8.54 kcal/mol and Ki value of 0.55 μM, which surpassed the positive controls. In conclusion, our study revealed that R. podophylla possessed remarkable antioxidant and anti-hyperuricemia activities and that the UF-LC-MS method is suitable for screening potential ligands for SOD and XOD from medicinal plants.

Role of NLRP3 in the pathogenesis and treatment of gout arthritis

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

Relief effects of Laoshan cherry extracts as a dietary supplement against the symptoms of acute gouty arthritis in rats induced by urate crystals

We evaluated the effects of Laoshan cherry as a food or dietary supplement on relieving the symptoms of acute gouty arthritis in rats induced by urate crystals. Rats in groups of 10 were given Laoshan cherry functional extracts at doses of 5, 10, and 20 mg/kg by oral gavage for 21 days and then injected with a sodium nitrate suspension in the rear ankle area as an induced acute gouty arthritis model. The ankle swelling and inflammations in the model (no treatment) group increased significantly compared with blank group; the ankle inflammations reduced in experimental groups receiving three different doses of the cherry extract and the joint swelling reduced in the high-dose group by 43% compared with the model group. Serum uric acid and xanthine oxidase activities were also elevated in the model group and these parameters were reduced by a maximum of 8% and 33%, respectively, in the rats receiving the cherry extracts. The serum levels of the inflammatory cytokine IL-1β in the high-dose group decreased by 12% compared with the model group. These results demonstrated that the cherries possess a functional substance that has a significant alleviating effect on the symptoms of gouty arthritis in rats induced by sodium urate injection.

Towards the Development of Dual Hypouricemic and Anti-inflammatory Candidates: Design, Synthesis, Stability Studies and Biological Evaluation of Some Mutual Ester Prodrugs of Febuxostat-NSAIDs

Treatment of gout involves two basic approaches: reducing the serum uric acid mainly by xanthine oxidase inhibitors (XOIs) and alleviating the intensity of the accompanying acute arthritic inflammation using non-steroidal anti-inflammatory drugs (NSAIDs). Febuxostat (FEB) is the first non-purine XOI approved for the treatment of hyperuricemia and gout. The present study aims at combining the hypouricemic effect of FEB and the anti-inflammatory (AI) properties of NSAIDs in a single entity by adopting the "mutual prodrug" approach. Accordingly, a series of seven ester prodrugs comprising basically FEB together with different NSAIDs namely, diclofenac (4), ibuprofen (5), ketoprofen (6), indomethacin (7), naproxen (8), ketorolac (9) and etodolac (10) was synthesized. All the investigated seven prodrugs (4-10) were equipotent or even superior to their corresponding parent drugs in the hypouricemic and AI activities, together with a gastrointestinal (GI) safety profile. Among this series, the prodrug FEB-DIC (4) showed excellent dual in vivo hypouricemic and anti-inflammatory activity (43.60 % and 15.96 %, respectively) when compared to the parent drugs FEB and diclofenac (36.82 % and 12.10 %, respectively) and its physical mixture (37.28 % and 12.41 %, respectively). Investigation of the in vitro chemical stability and hydrolysis of the prodrug (4) in aqueous and biological samples using a developed HPLC method confirmed its stability in various pHs, whereas rapid hydrolysis to the parent drugs in liver homogenate and human plasma was proven. Finally, it is concluded that the mutual prodrug approach could be successfully used in drug design and development for overcoming undesirable difficulties without losing the desired activities of the parent drugs.

A Selective Review and Virtual Screening Analysis of Natural Product Inhibitors of the NLRP3 Inflammasome

The NLRP3 inflammasome is currently an exciting target for drug discovery due to its role in various inflammatory diseases; however, to date, no NLRP3 inhibitors have reached the clinic. Several studies have used natural products as hit compounds to facilitate the design of novel selective NLRP3 inhibitors. Here, we review selected natural products reported in the literature as NLRP3 inhibitors, with a particular focus on those targeting gout. To complement this survey, we also report a virtual screen of the ZINC20 natural product database, predicting favored chemical features that can aid in the design of novel small molecule NLRP3 inhibitors.

Yishen Capsule Alleviated Symptoms of Diabetic Nephropathy via NOD-like Receptor Signaling Pathway

PURPOSE

To explore the mechanism of Yishen capsule against diabetic nephropathy (DN) based on the analysis of transcriptomics.

MATERIAL AND METHODS

SD rats (Male, SPF grade) were randomly divided into four groups, the normal group, the DN group, the Yishen capsule group and the resveratrol group. Urine and renal tissue samples were collected after feeding with physiological saline and above drugs for 8 weeks. 24-hour urine microalbumin protein was detected by ELISA. HE staining and PAS staining were performed on renal tissues. Differential gene expression in renal tissues was analyzed by transcriptome sequencing. The differentially expressed genes were analyzed by GO enrichment and KEGG enrichment, and verified by RT-PCR and immunohistochemistry staining.

RESULTS

The level of 24-hour urinary microalbumin in DN group was increased, while Yishen capsule treatment reversed the increasement of urinary microalbumin. Mesangial cell proliferation, matrix accumulation, edema and vacuolar degeneration of renal tubular epithelial cells and glycogen accumulation were observed in DN group. However, pathological phenotypes mentioned above were alleviated after Yisen capsule administration. This result indicates that Yishen capsule reversed pathological phenotypes of DN in rats. The expression of 261 genes were changed in Yishen capsule group compared with DN group. GO enrichment analysis and KEGG pathway analysis showed that these genes were implicated in pathways, including mineral absorption, adipocytokine signaling pathway, fatty acid biosynthesis, thyroid hormone synthesis, renin-angiotensin system, and NOD-like receptor signaling pathway. Based on previous reported study, the expression of key factors in NOD-like receptor signaling pathway was verified. RT-PCR and immunohistochemistry staining showed that the expression of NLRP3, Caspase-1 and IL-1β in renal tissues of DN group were increased (P < 0.05), which were decreased in Yishen capsule group (P < 0.05).

CONCLUSION

Yishen capsule reduced microalbuminuria and alleviated pathological changes in DN rats, which may be achieved by regulating NOD-like receptor signaling pathway.

Febuxostat-based amides and some derived heterocycles targeting xanthine oxidase and COX inhibition. Synthesis, in vitro and in vivo biological evaluation, molecular modeling and in silico ADMET studies

Various febuxostat derivatives comprising carboxamide functionalities and different substituted heterocycles were synthesized and evaluated for their biological activities as xanthine oxidase (XO) and cyclooxygenase (COX) inhibitors. All the tested compounds exhibited variable in vitro XO inhibitory activities (IC₅₀ values 0.009-0.077 µM), among which the analog 17 has emerged as the most potent derivative (IC₅₀ 0.009 µM), representing nearly 3-times the potency of febuxostat (IC₅₀ 0.026 µM). The same analogs were further investigated for their in vitro COX-1 and COX-2 inhibitory activity, where fifteen analogs demonstrated recognizable COX-2 inhibitory potential (IC₅₀ values range 0.04 - 0.1 µM), when correlated with celecoxib (IC₅₀ 0.05 µM), together with appreciable selectivity indices. Compounds 5a, 14b, 17, 19c, 19e and 21b that showed significant in vitro XO and/ or COX inhibitory potentials were further investigated for their in vivo hypouricemic as well as anti-inflammatory activities. Interestingly, the in vivo results were concordant with the collected in vitro data. Docking of compounds 5a, 14b, 17, 19c, 19e and 21b with the active sites of XO and COX-2 isozymes demonstrated superior binding profile compared with the reported ligands (febuxostat and celecoxib, respectively). Their docking scores were reasonable and cohering to a great extent with their corresponding in vitro IC₅₀ values. Moreover, in silico computation of the predicted pharmacokinetic and toxicity properties (ADMET), together with the ligand efficiency (LE) of the same six compounds suggesting their liability to act as new orally active drug candidates with a predicted high safety profile.

Xanthine oxidase inhibitory peptides derived from tuna protein: virtual screening, inhibitory activity, and molecular mechanisms

BACKGROUND

There has been growing interest in the use of xanthine oxidase (XO) as a therapeutic agent to prevent gout and hyperuricemia. In the present study, XO inhibitory peptides were identified from tuna protein by virtual screening, and molecular docking was used to elicit the interaction mechanism between XO and peptides.

RESULTS

A novel tetrapeptide, EEAK, exhibited high XO inhibitory activity with an IC₅₀ of 173.00 ± 0.06 μM. Molecular docking analysis revealed that EEAK bound with the pivotal residues of XO's active sites (i.e., Glu802, Arg880, Glu1261) through two conventional hydrogen bond interactions, two attractive charge interactions, and one salt bridge. EEAK could also bind with the residues Phe649, Leu648, Lys771, Ser876, Phe914, and Thr1010 of XO.

CONCLUSION

This study suggested that conventional hydrogen bond interactions and electrostatic interactions play an important role in XO inhibition. The novel XO inhibitory peptide EEAK from tuna protein could be used as potential candidate for controlling gout and hyperuricemia. © 2020 Society of Chemical Industry.

Design, Synthesis, Anticancer Activity, and Solid Lipid Nanoparticle Formulation of Indole- and Benzimidazole-Based Compounds as Pro-Apoptotic Agents Targeting Bcl-2 Protein

Cancer is a multifactorial disease necessitating identification of novel targets for its treatment. Inhibition of Bcl-2 for triggered pro-apoptotic signaling is considered a promising strategy for cancer treatment. Within the current work, we aimed to design and synthesize a new series of benzimidazole- and indole-based derivatives as inhibitors of Bcl-2 protein. The market pan-Bcl-2 inhibitor, obatoclax, was the lead framework compound for adopted structural modifications. The obatoclax’s pyrrolylmethine linker was replaced with straight alkylamine or carboxyhydrazine methylene linkers providing the new compounds. This strategy permitted improved structural flexibility of synthesized compounds adopting favored maneuvers for better fitting at the Bcl-2 major hydrophobic pocket. Anti-cancer activity of the synthesized compounds was further investigated through MTT-cytotoxic assay, cell cycle analysis, RT-PCR, ELISA and DNA fragmentation. Cytotoxic results showed compounds 8a, 8b and 8c with promising cytotoxicity against MDA-MB-231/breast cancer cells (IC₅₀ = 12.69 ± 0.84 to 12.83 ± 3.50 µM), while 8a and 8c depicted noticeable activities against A549/lung adenocarcinoma cells (IC₅₀ = 23.05 ± 1.45 and 11.63 ± 2.57 µM, respectively). The signaling Bcl-2 inhibition pathway was confirmed by molecular docking where significant docking energies and interactions with key Bcl-2 pocket residues were depicted. Moreover, the top active compound, 8b, showed significant upregulated expression levels of pro-apoptotic/anti-apoptotic of genes; Bax, Bcl-2, caspase-3, -8, and -9 through RT-PCR assay. Improving the compound’s pharmaceutical profile was undertaken by introducing 8b within drug-solid/lipid nanoparticle formulation prepared by hot melting homogenization technique and evaluated for encapsulation efficiency, particle size, and zeta potential. Significant improvement was seen at the compound’s cytotoxic activity. In conclusion, 8b is introduced as a promising anti-cancer lead candidate that worth future fine-tuned lead optimization and development studies while exploring its potentiality through in-vivo preclinical investigation.