Abstract: Objective: To investigate the regulatory effect of soybean-derived exosome-like nanovesicles (SELNs) on lipid metabolism in Caenorhabditis elegans. Methods: SELNs were isolated and purified from soybean by ultracentrifugation combined with sucrose density gradient centrifugation. The composition of SELNs was analyzed. The stability of SELNs to in vitro digestion was evaluated. The effects of SELNs (1–100 μg/mL) on the content of lipid droplets in hyperlipidemic C. elegans induced by sodium palmitate (SP) were monitored by two staining methods for neutral lipids: Nile red (NR) and oil red O (ORO), and the content of triglyceride (TG) was determined. The effects of SELNs on the expression of key genes associated with lipid metabolism in C. elegans were analyzed by polymerase chain reaction (PCR). Results: SELNs were rich in lipid, protein and nucleic acid. The structure of SELNs was stable in the stomach acid environment but was broken in the intestinal fluid. SELNs inhibited the formation of lipid droplets induced by SP, significantly down-regulated the abnormal increase in the relative mRNA expression of fat-5, fat-6 and fat-7 induced by SP, and up-regulated the relative mRNA expression of aak-2. Meanwhile, SELNs significantly up-regulated and down-regulated the relative expression of daf-2 and daf-16, respectively. Conclusion: Moderate intake of SELNs can regulate the expression of key genes associated with lipid metabolism, inhibit lipid droplet generation, and consequently reduce lipid deposition.

Key words: soybean-derived exosome-like nanovesicles; Caenorhabditis elegans; fat accumulation; lipid metabolism; regulatory effect