Lactobacillus gasseri JM1, a novel strain isolated from infant feces, exhibited common probiotic properties such as high acid tolerance, bile salt tolerance, and adhesion to epithelial Caco-2 cells, suggesting its ability to survive in the gastrointestinal tract and confer potential probiotic action on the host. In the current study, we aimed to evaluate the immunomodulatory activity of L. gasseri JM1 and explore the underlying signaling pathways in vitro. The results showed that pretreatment with L. gasseri JM1 alleviated lipopolysaccharide-induced inflammatory response, as evidenced by downregulation of genes encoding proinflammatory cytokines [IL1B, IL6, IL8, and tumor necrosis factor-α (TNFA)] and upregulation of genes encoding anti-inflammatory cytokines [IL4, IL10, transforming growth factor-β3 (TGFB3), and IFNG]. A high level of gene expression was noted for toll-like receptor 2 and NOD-like receptor 2. Meanwhile, transcriptomic sequencing obtained 84 differentially expressed genes. Kyoto Encyclopedia of Genes and Genomes analysis revealed the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was activated by L. gasseri JM1 in Caco-2 cells. Inhibitor of PI3K/Akt played various roles in the release of cytokines, indicating that the pathway was involved in protecting the host against lipopolysaccharide stress. Moreover, whole-genome sequencing revealed fundamental genetic properties of L. gasseri JM1 and provided clues for probiotic characteristics. In summary, the strain could exert immunomodulatory effects via the toll-like receptor 2 and NOD2-mediated PI3K/Akt signaling pathway and be regarded as a potential probiotic.

Gasseri JM1乳杆菌是一种从婴儿粪便中分离出来的新型菌株，表现出常见的益生菌特性，例如高酸耐受性，胆汁盐耐受性以及对上皮Caco-2细胞的粘附性，表明其在胃肠道中存活并赋予潜在的益生菌作用的能力。主人。在当前的研究中，我们旨在评估L. gasseri JM1的免疫调节活性，并探索体外的潜在信号传导途径。结果表明，用加氏乳杆菌JM1预处理可减轻脂多糖诱导的炎症反应，如编码促炎细胞因子[ IL1B，IL6，IL8和肿瘤坏死因子-（TNFA）]和编码抗炎细胞因子[ IL4，IL10，转化生长因子-β3（TGFB3）和IFNG ]的基因上调。Toll样受体2和NOD样受体2的基因表达水平很高。同时，转录组测序获得了84个差异表达的基因。《京都议定书》的基因和基因组分析显示，磷脂酰肌醇3-激酶（PI3K）/蛋白激酶B（Akt）信号通路被加氏乳杆菌激活Caco-2细胞中的JM1。PI3K / Akt抑制剂在细胞因子释放中起多种作用，表明该途径与保护宿主抵抗脂多糖应激有关。此外，全基因组测序揭示了L. gasseri JM1的基本遗传特性，并为益生菌特性提供了线索。总之，该菌株可以通过toll样受体2和NOD2介导的PI3K / Akt信号通路发挥免疫调节作用，被认为是一种潜在的益生菌。