Extracellular Vesicles from Lactobacillus rhamnosus BS-Pro-08, Kefir Grain, Suppress Adipogenesis and Enhance Lipolysis in Adipocytes

Extracellular vesicles (EVs) derived from probiotic bacteria have recently emerged as postbiotic mediators that regulate host cellular responses. This study investigated the effects of EVs from Lactobacillus rhamnosus BS-Pro-08, isolated from kefir grains (Lacto EV), on adipocyte differentiation and lipid metabolism. Lacto EV treatment markedly suppressed the differentiation of 3T3-L1 preadipocytes into mature adipocytes, as reflected by reduced lipid accumulation and decreased expression of the adipogenic transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα). This inhibitory effect was most pronounced at the early stage of adipogenesis. In mature adipocytes, Lacto EV enhanced lipolysis in a dose-dependent manner, accompanied by increased glycerol release and total lipase activity. Interestingly, these lipolytic responses occurred despite reduced protein levels of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), suggesting that Lacto EVs may mediate an EV-enhanced lipolysis that is not fully explained by canonical ATGL/HSL signaling. Collectively, these findings demonstrate that Lacto EV modulates both adipogenic and lipolytic processes in vitro, providing insight into the metabolic actions of probiotic-derived vesicles.