BACKGROUND: The gut-brain axis is increasingly recognized as a key regulator of neurological health, with microbial metabolites influencing neurotransmission, synaptic plasticity, and neuroinflammation. Probiotics such asGG and1714 have been associated with neuroactive effects, yet the molecular mechanisms linking microbial genomic potential to host neuronal responses remain poorly defined. Lactobacillus rhamnosus Bifidobacterium longum
OBJECTIVE: This study aimed to integrate microbial genomics, neurotranscriptomics, andvalidation to unravel the neuromodulatory effects ofGG and1714in vitro L. rhamnosus B. longum
METHODS: Whole-genome functional annotation, metabolic pathway prediction, and biosynthetic gene cluster analysis were performed to identify neuroactive potential. Neuronal RNA-seq datasets (n = 3 biological replicates per condition) were analyzed using differential expression, WGCNA, and GSEA to capture transcriptomic responses. Multi-omics integration (CCA, DIABLO, SPIEC-EASI) linked microbial pathways with neuronal gene modules.assays using SH-SY5Y and iPSC-derived neurons validated predictions through measurements of cell viability, oxidative stress, neurotransmitter release (ELISA), qPCR of synaptic and inflammatory genes, and extracellular vesicle characterization including EV transcript profiling. In vitro
RESULTS: Genomic analysis revealed thatGG was enriched in γ-aminobutyric acid (GABA)</span> and SCFA pathways, while1714 carried tryptophan-indole metabolism genes. Transcriptomic profiling demonstrated upregulation of synaptic genes (BDNF, SYN1), showed upregulation of synaptic genes (,), serotonergic transporters (,), and suppression of inflammatory mediators (,). Integration analyses identified two major subnetworks: a "neurotransmission module" driven byGG and a "serotonin-immune module" driven by1714validation confirmed increased GABA (1.7-fold) and serotonin (1.5-fold) release, reduced ROS (-18 to -22%), and EV transcript enrichment for synaptic and anti-inflammatory markers. L. rhamnosus B. longum BDNF SYN1SLC6A4TPH2IL-6TNF-α L. rhamnosus B. longum In vitro
CONCLUSION: This multi-omics study demonstrates mechanistic evidence that probiotics exert complementary neuromodulatory effects:GG primarily enhances GABAergic and SCFA-mediated synaptic pathways, whereas1714 regulates the tryptophan-serotonin-immune axis. Together, these findings support the therapeutic potential of precision probiotics for neurological health and establish a systems-level framework for probing host-microbe interactions. L. rhamnosus B. longum
Gut-Brain Axis