Effects of plant-based heat killed lactic acid bacteria and its lithium chloride-extracted cellular protein on high-fat-induced obesity

The anti-obesity action of postbiotics derived from plant-based probiotics remains unclear. The effects of heat killed lactic acid bacteria (Lactobacillus plantarum, LPHK and Lactobacillus curvatus, LCHK) along with bioactive their cell envelop components known as surface layer proteins (SLPs, LPSLP, and LCSLP) on obesity were investigated. LPHK, LCHK, LPSLP, and LCSLP significantly reduced lipid accumulation in 3T3-L1 adipocytes, concurrently regulating the expression of adipogenic genes. Notably, LPHK demonstrated significant improvements in high-fat (HF)-induced body weight gain, adipose tissue weight gain, liver weight gain, and reduced plasma concentrations of triglyceride, total-cholesterol, and LDL-cholesterol in C57BL/6J mice. Additionally, LPHK significantly regulated the expression of genes related to adipogenesis and anti-apoptosis. Moreover, while LPSLP significantly reduced liver weight, plasma triglyceride and LDL-cholesterol concentrations, and upregulated genes associated with hepatic fatty acid oxidation, it did not affect the body weight and adipose tissue weight gain. These results suggest that additional components other than SLP are necessary for the anti-obesity action of LPHK. In conclusion, non-viable plant-based LPHK can be used as a naturally occurring product for preventing obesity, especially in individuals with immunocompromised conditions.