Limosilactobacillus fermentum MG4244 Protects Against Metabolic and Inflammatory Stress in Caenorhabditis elegans

In this study, we investigated the effects of MG4244 on intestinal permeability, oxidative stress, and lipid accumulation in Caenorhabditis elegans with metabolic inflammation induced by Pseudomonas aeruginosa (PA) and a high-glucose diet (HGD). The worms infected with PA exhibited increased intestinal permeability and reactive oxygen species (ROS) production, which were improved upon MG4244 treatment. Also, MG4244 inhibited lipid and ROS accumulation induced by an HGD. In addition, MG4244-treated worms showed extended lifespans under various conditions. To elucidate the mechanism of the MG4244 effects, we conducted further investigation using mutant strains with knockdown of genes associated with the AMP-activated protein kinase (AMPK) and mitogen-activated protein kinase (MAPK) pathways. The results demonstrated that the MG4244 effect on lipid metabolism was primarily mediated through the AMPK signaling pathway. Furthermore, MG4244 enhanced pathogen resistance by MAPK signaling pathways, mitigating stress responses, and maintaining intestinal integrity. In further studies, combined treatment with PA and an HGD significantly increased intestinal permeability, lipid, and ROS levels, confirming their negative synergistic effects. However, MG4244 under PA and HGD co-treatment conditions effectively mitigated these health disruptions, suggesting a protective role of MG4244. This study provides an in vivo platform using C. elegans to evaluate probiotic efficacy related to the intestinal environment. Also, our results highlight the therapeutic potential of MG4244 in improving resilience to metabolic inflammation through gut-targeted mechanisms.