Flammulina velutipes mycorrhizae dietary fiber improves lipid metabolism disorders in obese mice through activating AMPK signaling pathway mediated by gut microbiota.

Mounting evidence shows that dietary fiber (DF) alleviates lipid metabolism disorders in humans and animals by regulating the gut microbiota. However, its action mechanisms remain to be elucidated. Flammulina velutipes (F. velutipes) as an edible mushroom is widely cultivated in China and has medicinal values. As a by-product of F. velutipes , the mycorrhizae are rich in high-quality DF and therefore can be used to prepare F. velutipes DF (Fv-DF). The objective of this research aimed to explore whether and how Fv-DF attenuates lipid metabolism disorders in obese mice through the gut microbiota. Here, an obese mice model induced by high-fat diet was established to analyze the effect of Fv-DF supplementation on the lipid metabolism disorders and gut microbiota. The results showed that Fv-DF administration significantly reduced the weight gain, triglycerides and total cholesterol, low-density lipoprotein cholesterol and markedly increased the activity of enzymes related to scavenging ability of oxygen free radicals. The gut microbiota sequencing exhibited that the Fv-DF supplementation increased the level of gut beneficial bacteria, such as Prevotellaceae UCG-001 and Alloprevotella. Western blot analysis revealed the phosphorylated adenosine 5′-monophosphate (AMP)-activated protein kinase (p -AMPKα) was up-regulated, indicating that AMPK signaling pathway was activated. The activated pathway down-regulated the fatty acid synthase level to decrease lipid synthesis and up-regulated the carnitine palmitoyl transferase-1 level to increase lipid degradation. Altogether, Fv-DF supplementation alleviates lipid metabolism disorders in obese mice by regulating the gut microbiota-mediated AMPK signaling pathway. [Display omitted] (1) Fv-DF reduced the weight gain and improved physiological indexes in obese mice. (2) Fv-DF improved the abundance and composition of gut microbiota. (3) The changed microbiota activated AMPK signaling pathway. (4) AMPK pathway activation may be a major contributor to alleviate obesity. [ABSTRACT FROM AUTHOR]