Identification of immune-associated genes with altered expression in the spleen of mice enriched with probiotic Lactobacillus species using RNA-seq profiling.

Objective: Probiotics are living microorganisms that can provide health benefits when consumed. Here, we investigated the effects of probiotics on gene expression in the spleen of mice using RNA-sequencing analysis between negative control and probiotic groups (including 4 Lactobacillus strains: Lactobacillus fermentum, L. casei, L. plantarum, and L. brevis).

Methods: Mice exposed with probiotic in 4 weeks by intragastric administration. Then, spleen tissues of the control and probiotics groups were collected on days 14 and 28 for RNA sequencing.

Results: In total, 665, 186, and 81 differentially expressed genes (DEGs) were significantly expressed on day 14 vs control, day 28 vs control groups, and probiotics day 28 vs day 14 groups, respectively. On the other hand, 12 toll-like receptor genes underwent additional validation through quantitative real-time polymerase chain reaction (qRT-PCR), affirming the increased alignment between qRT-PCR and RNA-Seq findings. In addition, the Kyoto encyclopedia of genes and genomes and gene ontology analyses revealed that the DEGs were predominantly enriched in defense responses to pathogens, including inflammatory bowel diseases, malaria, leukaemia virus 1, and herpes virus, as well as immune processes related to immune response and signal transduction. This study represents the first investigation into mice's gene expression in the spleen exposed to probiotics using Lactobacillus spp. isolated from a field strain in Vietnam.

Conclusion: Our results provide valuable insights into the impacts and functions of probiotics on mammalian development, offering crucial information for the potential therapeutic use of probiotics in defending against pathogens in Vietnam. The findings from this study highlight the potential of probiotics in modulating gene expression in the spleen, which may have implications for immune function and overall health in mice.