Metagenomic and transcriptomic profiling of the hypoglycemic and hypotriglyceridemic actions of Tremella fuciformis-derived polysaccharides in high-fat-diet- and streptozotocin-treated mice.

Abstract

Mushroom polysaccharides have great anti-diabetes potential. The fruiting body of Tremella fuciformis is rich in polysaccharides. However, few studies have been performed to date on T. fuciformis-derived polysaccharides (TPs) in terms of anti-diabetes potential. Our previous studies showed that novel TPs with medium molecular weights exhibited the highest anti-skin aging activities among the tested samples in D-galactose-treated mice. In the present study, the effects of these novel TPs, named TP, on high-fat-diet- and streptozotocin-treated mice were assessed, and their potential biological mechanisms were explored by metagenomic and transcriptomic analyses. Oral administration of TP markedly reduced blood glucose and TG levels, alleviated emaciation, improved anti-oxidant capacity, and protected the functions of β-cells at a dose of 100 mg kg^-1 in diabetic mice. Meanwhile, the taxonomic compositions and functional properties of fecal microbiota were altered considerably by TP, as evidenced by partial restoration of the imbalanced gut microbiota and the higher abundances of Bacteroides, Phocaeicola, Bifidobacterium, and Alistipes compared to the model mice, corresponding to the upregulation of four enriched KEGG pathways of microbial communities such as the digestive system, cardiovascular disease, parasitic infectious disease, and cell growth and death. Further transcriptomic analysis of liver tissues identified 35 enriched KEGG pathways associated with metabolism and cellular signaling processes in response to TP. These results demonstrated the biological mechanisms underlying the hypoglycemic and hypotriglyceridemic activities of TP. The findings expanded our understanding of the anti-diabetic mechanisms for mushroom polysaccharides and provided new clues for future studies.