Geroprotective Effect of Levilactobacillus brevis and Weizmannia coagulans in Caenorhabditis elegans

The prophylactic use of lactic acid bacteria (LAB) to maintain human health is one of the most important research areas in recent times. LAB supplementation confers a wide range of health benefits to the host, but few studies have focused on their possible role in delaying the aging process. This study explored the health and life-promoting properties of two LAB, Levilactobacillus brevis and Weizmannia coagulans, using the Caenorhabditis elegans model. We found that L. brevis and W. coagulans enhanced the intestinal integrity and intestinal barrier functions without affecting the overall physiological functions of C. elegans. Wild-type worms preconditioned with LAB strains increased their survival under oxidative and thermal stress conditions by reducing intracellular reactive oxygen levels. Live L. brevis and W. coagulans significantly extended the lifespan of C. elegans under standard laboratory conditions independently of dietary restrictions. Genetic and reporter gene expression analysis revealed that L. brevis and W. coagulans extend lifespan via insulin/insulin-like growth factor-1 signaling and the p38 MAPK signaling axis. Furthermore, sirtuin, JNK MAPK, and mitochondrial respiratory complexes were found to be partially involved in W. coagulans-mediated lifespan extension and stress resilience. Preconditioning with LAB ameliorated age-related functional decline in C. elegans and reduced ectopic fat deposition in an NHR-49-dependent manner. Together, our findings indicated that L. brevis and W. coagulans are worth exploring further as "gerobiotic" candidates to delay aging and improve the healthspan of the host.