Abstract: BACKGROUND: Existing pharmacological treatments for gout are frequently limited by substantial side effects, underscoring the urgent need to discover novel therapeutic targets and develop more targeted drugs.
OBJECTIVE: To identify genetic targets for gout, and to predict promising therapeutic compounds as well as traditional Chinese medicines by integrating druggable gene datasets with Mendelian randomization and colocalization analysis approaches. This work will lay a foundation for in-depth exploration of the pathogenesis of gout in the Chinese population, and provide insights for the clinical management of gout as well as the development of new targeted drugs. 
METHODS: The gout-related dataset was acquired from FinnGenR11, a database developed by the Finnish National Genetic Research Project. Blood expression quantitative trait loci data for exposure factors were obtained from the genome-wide association studies directory website maintained by the Integrative Epidemiology Unit at the University of Bristol's Medical Research Council. Mendelian randomization analysis was employed to identify potential therapeutic targets, while co-localization analysis helped determine key susceptibility genes for gout. Gene functions were investigated through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Protein-protein interaction networks were utilized to screen closely interacting targets. Potential therapeutic compounds were predicted using the drug-gene interaction database developed by Washington University School of Medicine in St. Louis, USA. Molecular docking predicted binding affinities between compounds and core targets, while the Coremine Medical database by PubGene Company helped identify relevant traditional Chinese medicines. All databases used were publicly available resources. For experimental validation, a gout cell model was established using monosodium urate crystal-induced RAW264.7 cells to preliminarily assess key gene expression and compound intervention effects. Safe doses and optimal concentrations were determined through CCK-8 assays and cell invasion assays. Inflammatory factor levels were measured using enzyme-linked immunosorbent assay, and real-time PCR was employed to detect mRNA expression of key targets and pathway components.
RESULTS AND CONCLUSION: (1) Mendelian randomization analysis identified 40 potential gene targets significantly associated with gout. Colocalization analysis determined Jun as a key susceptibility gene for gout. The protein interaction network revealed that Jun proto-oncogene, mitogen-activated protein kinase 3, and 3-hydroxy-3-methylglutaryl-CoA reductase demonstrate close interactions. (2) Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the potential targets primarily functioned through modulation of key signaling pathways, including mitogen-activated protein kinase, tumor necrosis factor, ErbB, interleukin-17, hypoxia-inducible factor-1, and Toll-like receptor pathways. These targets appear to mediate biological processes such as positive regulation of extracellular signal-regulated kinase 1/2 cascade, glutathione metabolism, and ubiquitin-protein regulatory systems. (3) Based on potential targets, 372 compounds with possible intervention effects were predicted, such as capsaicin, 5,6-benzoflavone, L-glutamic acid, quercetin, magnolol, kaempferol, cinnamaldehyde, and andrographolide. (4) Molecular docking analysis revealed that capsaicin and 5,6-benzoflavone had a high binding degree with core targets such as Jun. (5) Totally 79 potential targeted traditional Chinese medicines were identified through prediction, including Atractylodes lancea, Magnolia officinalis, Smilax glabra, Alisia orientalis, and Salvia miltiorrhiza, with primary therapeutic functions including heat clearance and detoxification, blood activation and stasis resolution, and phlegm-dampness dissipation. (6) CCK-8 and cell invasion assays demonstrated that the optimal safe concentration of capsaicin was 50 μmol/L. The expression of the key gene Jun proto-oncogene was significantly upregulated in the model group. Meanwhile, capsaicin markedly downregulated the expression of Jun proto-oncogene and mRNA associated with the mitogen-activated protein kinase pathway, including c-Jun amino-terminal kinase, extracellular signal-regulated kinase 1/2, and p38. Additionally, it reduced the levels of interleukin-6, interleukin-1β, and tumor necrosis factor α in the cell supernatant. (7) Data mining results indicate that compounds including capsaicin and 5,6-benzoflavonoids, along with traditional Chinese medicines such as Atractylodes lancea and Smilax glabra, may potentially intervene in gout by targeting molecules such as Jun proto-oncogene and mitogen-activated protein kinase 3. These interventions appear to regulate multiple pathways, including tumor necrosis factor signaling, Th-17 cell differentiation, hypoxia-inducible factor 1 signaling, mitogen-activated protein kinase cascades, protein ubiquitination, and glutathione metabolism. Notably, the key susceptibility gene JUN may serve as a potential diagnostic marker for gout. The primary therapeutic approach for gout involves clearing heat and toxins combined with promoting blood circulation and resolving blood stasis. (8) The cell experiments provided preliminary verification of JUN gene expression and mitogen-activated protein kinase pathway activity in the gout cell model, as well as the therapeutic effects of capsaicin intervention. These findings establish a foundation for subsequent research on gout diagnostic and therapeutic targets, as well as new drug development.  

Key words: gout, drugable gene, Mendelian randomization, drug prediction, traditional Chinese medicine prediction, co-localization, Jun proto-oncogene, capsaicin, mitogen-activated protein kinase signaling pathway