Lactiplantibacillus plantarum TO-A Reduces Fat Accumulation in Caenorhabditis elegans via pept-1

Lactic acid bacteria (LAB) have dominated food fermentation globally and are ingrained in many food cultures. Obesity is a global health concern, and LAB ingestion is known to exert anti-obesity effects in animals. However, the characteristics of individual bacterial strains and their underlying mechanisms require elucidation since the anti-obesity effects can differ with variations in the strain, host, and living environment. In this study, we aimed to evaluate the safety and anti-obesity effects of Lactiplantibacillus plantarum TO-A (LPTOA), isolated from silage, using Caenorhabditis elegans as the model organism. The study findings revealed that LPTOA was non-toxic to mice, as established via subacute toxicity tests, and extended the lifespan of C. elegans. Furthermore, both LPTOA and heat-killed LPTOA reduced fat accumulation in C. elegans by 60% and 58%, respectively. However, in vitro experiments suggested that LPTOA does not decompose cholesterol and triglycerides, nor does it inhibit lipase activity. We identified that pept-1 (a dipeptide transporter) in C. elegans is involved in the anti-obesity effects of LPTOA. PEPT-1 is a protein that controls proton influx into the intestinal tract and is involved in not only peptide uptake but also free fatty acid absorption. These results demonstrate the anti-obesity effects and probiotic potential of LPTOA for application in products, including foods and supplements.