Integrating metagenomics, transcriptomics, and molecular docking to reveal core gene biomarkers and gut microbiota regulatory mechanisms in tuberculous meningitis.

PURPOSE: Tuberculous meningitis (TBM) is a severe extrapulmonary tuberculosis with high mortality and neurological sequelae, while the role of gut microbiota and its metabolites in TBM pathogenesis remains poorly understood. This study aimed to characterize gut microbiota alterations in TBM patients and elucidate the "microbiota-metabolite-gene" regulatory axis. METHODS: Fecal samples from 11 TBM patients and 11 healthy controls were subjected to 16S rRNA sequencing. Core target genes were identified via differential expression screening, machine learning, immune infiltration analysis and gene set enrichment analysis based on the public GSE40586 dataset. The regulatory axis was constructed by database prediction and molecular docking, and the regulatory effect was verified by in vitro functional assays in THP-1-derived macrophages. RESULTS: TBM patients exhibited significant gut dysbiosis. Two core genes (PIK3CB and JAK2) were identified, which were positively correlated with pro-inflammatory immune cells and enriched in bacterial infection pathways. The constructed regulatory axis showed that upregulated gut bacteria produced bile acid metabolites targeting PIK3CB/JAK2, with strong binding affinity verified by molecular docking. In vitro experiments verified that CDCA dose-dependently upregulated PIK3CB and JAK2 expression and promoted pro-inflammatory activation of macrophages, while silencing of target genes significantly reversed this effect. CONCLUSION: This study identifies a "gut microbiota-bile acid-PIK3CB/JAK2" regulatory axis in TBM, thus providing novel insights into gut-brain crosstalk and potential diagnostic biomarkers and therapeutic targets.