Poria cocos-Derived Exosome-like Nanovesicles Alleviate Metabolic Dysfunction-Associated Fatty Liver Disease by Promoting Mitophagy and Inhibiting NLRP3 Inflammasome Activation

Metabolic dysfunction-associated fatty liver disease (MAFLD) affects approximately one-quarter of the world's adult population, and no effective therapeutic drugs are available. Poria cocos is a fungus used as a herb and food nutrient for centuries as well as for MAFLD treatment. Exosome-like nanovesicles have many pharmacological activities; however, studies on the effects of Poria cocos-derived exosome-like nanovesicles (PCELNs) on MAFLD are lacking. Therefore, our study aimed at identifying the effects and mechanism of action of PCELNs on MAFLD. PCELNs were isolated by ultracentrifugation and their morphology was characterized, such as particle size, zeta potential, protein distributions, as well as lipid and miRNA compositions. Then, the absorption and distribution of PCELNs were observed in vivo and in vitro. Finally, L02 cell steatosis model induced by fat emulsion and MAFLD mouse model induced by high-fat diet (HFD) were used to evaluate the effect and mechanism of PCELNs on MAFLD. PCELNs were membrane structured vesicles, with a particle size of 161.4 ± 1.7 nm, a zeta potential of -3.20 ± 0.37 mV, and contained a range of proteins, lipids, and miRNAs. PCELNs were absorbed by L02 cells and targeted the liver and spleen after intraperitoneal injection. PCELNs inhibited body weight gain and improved the index of heart, liver, spleen, and various fats, as well as decreased lipid accumulation and lipid level. They also protected mitochondrial ultrastructure and regulated oxidative stress and energy metabolism disorder. Furthermore, PCELNs increased PTEN induced kinase 1 (PINK1), E3 ubiquitin ligase (Parkin) and microtubule associated protein light chain-3 (LC3) protein expression in the liver, reduced oxidized mitochondrial DNA (Ox-mtDNA) content in mitochondria and cytoplasm of the liver, reduced nucleotide binding oligomerization domain-like receptor protein 3 (NLRP3), pro-cysteinyl aspartate specific proteinase-1 (caspase-1), cleared-caspase-1, and mature-interleukin-1β (IL-1β) protein expression in the liver, and reduced the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and interleukin-18 (IL-18) in serum and liver. In conclusion, we demonstrated that PCELNs may alleviate HFD-induced MAFLD by promoting mitochondrial autophagy and inhibiting NLRP3 inflammasome activation.