Immunomodulatory effects of postbiotics derived from Lacticaseibacillus casei strain RIGLD MG-1 on Helicobacter pylori-induced inflammation in gastric epithelial cells in vitro

The causative role of Helicobacter pylori ( H. pylori ) in gastric carcinogenesis underscores the importance of effective eradication for reducing gastric cancer burden. However, the alarming spread of antibiotic resistance and treatment-related adverse effects has challenged the effectiveness and tolerability of current eradication regimens, emphasizing the need for alternative therapeutic strategies. Postbiotics, defined as non-viable probiotic derivatives have gained increasing attention in H. pylori research owing to their safety, stability, and favorable tolerability profile. This study aimed to assess the immunomodulatory effects of Lacticaseibacillus casei ( L. casei ) strain RIGLD MG-1 derived cell-free supernatant (CFS) and membrane vesicles (MVs) on H. pylori -induced inflammatory response in human gastric adenocarcinoma (AGS) cells. MVs were isolated by ultracentrifugation and characterized by dynamic light scattering and transmission electron microscopy. Furthermore, the protein pattern of L. casei -derived MVs was also assessed by SDS-PAGE. Cell viability of AGS cells exposed to varying concentrations of CFS and MVs was determined by MTT assay. Inflammatory markers were examined by RT-qPCR and ELISA. The mRNA expression of NF-κB, IL-8, TNF-α, and β-catenin was considerably decreased in AGS cells upon L. casei MVs (100 µg/mL) and CFS treatment while restoring the anti-inflammatory cytokine IL-10. Consistently, the secretion of IL-8 and TNF-α was reduced, whereas IL-10 production was enhanced. This study reveals that postbiotics derived from the L. casei strain RIGLD MG-1 exert significant immunomodulatory effects on H. pylori -associated inflammation in vitro. Such immunomodulation may represent the therapeutic potential of probiotic-derived products in mitigating H. pylori -induced gastric inflammation and pathology.