A novel neuroprotective peptide YVYAETY identified and screened from Flammulina velutipes protein hydrolysates attenuates scopolamine-induced cognitive impairment in mice.

Flammulina velutipes protein hydrolysates are known for their abundant amino acids and excellent developmental values. This study aimed to identify and screen neuroprotective peptides from F. velutipes protein hydrolysates in vitro and validate the protective effects of YVYAETY on memory impairment in scopolamine-induced mice. The F. velutipes protein was hydrolyzed by simulated gastrointestinal digestion, followed by purification through ultrafiltration and gel chromatography. The fraction exhibiting the strongest neuroprotective activity was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The main identified peptides (SDLKPADF, WNDHYY, YVYAETY, and WFHPLF) effectively mitigated excessive ROS production by increasing SOD and GSH-px activities while inhibiting cell apoptosis and mitochondrial membrane potential (MMP) collapse against oxidative stress in Aß25-35-induced HT22 cells. By molecular docking, the interaction between peptides and the active site of the Keap1-Kelch domain reveals their capacity to regulate the Keap1/Nrf2/HO-1 pathway. In vitro, the peptide YVYAETY had the best effect and can be further validated in vivo. The behavioral tests showed that YVYAETY improved scopolamine-induced cognitive impairment in mice. YVYAETY also alleviated neuron damage including neuron vacuolation and pyknotic nuclei in the hippocampus. Furthermore, it significantly inhibited oxidative stress and suppressed the activation of the Nrf2 pathway. Therefore, this study revealed that YVYAETY had the potential to serve as a novel neuroprotective agent.

Bidirectional Solid-State Fermentation of Highland Barley by Edible Fungi to Improve Its Functional Components, Antioxidant Activity and Texture Characteristics.

In food industry, the characteristics of food substrate could be improved through its bidirectional solid-state fermentation (BSF) by fungi, because the functional components were produced during BSF. Six edible fungi were selected for BSF to study their effects on highland barley properties, such as functional components, antioxidant activity, and texture characteristics. After BSF, the triterpenes content in Ganoderma lucidum and Ganoderma leucocontextum samples increased by 76.57 and 205.98%, respectively, and the flavonoids content increased by 62.40% (Phellinus igniarius). Protein content in all tests increased significantly, with a maximal increase of 406.11% (P. igniarius). Proportion of indispensable amino acids increased significantly, with the maximum increase of 28.22%. Lysine content increased largest by 437.34% to 3.310 mg/g (Flammulina velutipes). For antioxidant activity, ABTS radical scavenging activity showed the maximal improvement, with an increase of 1268.95%. Low-field NMR results indicated a changed water status of highland barley after fermentation, which could result in changes in texture characteristics of highland barley. Texture analysis showed that the hardness and chewiness of the fermented product decreased markedly especially in Ganoderma lucidum sample with a decrease of 77.96% and 58.60%, respectively. The decrease indicated a significant improvement in the taste of highland barley. The results showed that BSF is an effective technology to increase the quality of highland barley and provide a new direction for the production of functional foods.

Modulation of gut microbiota and metabolites by Flammulina velutipes polysaccharides during in vitro human fecal fermentation: Unveiling Bacteroides as a potential primary degrader.

Flammulina velutipes, a widely cultivated species of edible fungus, exhibits diverse functional activities attributed to its polysaccharides. In this study, we employed an in vitro model to investigate the impact of F. velutipes polysaccharides (FVP) fermentation on gut microbiota, with a particular focus on Bacteroides. FVP fermentation resulted in the proliferation of microbiota associated with short-chain fatty acid (SCFA) metabolism and suppression of Escherichia-Shigella. Bacteroides emerged as potential primary degraders of FVP, with species-level analysis identifying the preference of B. thetaiotaomicron and B. intestinalis in FVP degradation. Metabolomics analysis revealed significant increases in hypoxanthine and 7-methyladenine contents, with histidine metabolism emerging as the most enriched pathway. B. nordii and B. xylanisolvens exhibited the most influence on amino acid and SCFA metabolism. Understanding the mechanisms by which gut microbiota metabolize FVP can provide valuable insights into the potential of FVP to promote intestinal health and disease prevention.

Impact of Flammulina velutipes polysaccharide on properties and structural changes of pork myofibrillar protein during the gel process in the absence or presence of oxidation.

The present study aimed to investigate the impact of Flammulina velutipes polysaccharide (FVSP) on the rheological properties and structural alterations of myofibrillar protein (MP) and oxidized MP (OMP), utilizing techniques such as rhehometer, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In the unoxidized system, the addition of 5.00% FVSP significantly improved (p < 0.05) the storage and loss moduli of the composite gel and promoted the α-helix to ß-sheet transformation. These effects enhanced the protein's gel strength and water-holding capacity (WHC). In the oxidation system, 5.00% FVSP had significant effects (p < 0.05) on repair and improvement of the oxidized MP. These effects inhibited the cross-linking aggregation and degradation of the protein. In addition, the addition of FVSP significantly improved the gel properties of MPs after oxidation (p < 0.05), hindered fracture of the protein gel network structure. In summary, polysaccharides have a substantial effect on the functional characteristics of MP, and FVSP could potentially be applied in meat products.

Research progress and future development potential of Flammulina velutipes polysaccharides in the preparation process, structure analysis, biology, and pharmacology: A review.

In recent years, Flammulina velutipes (F. velutipes) has attracted consequential attention in various research fields due to its rich composition of proteins, vitamins, amino acids, polysaccharides, and polyphenols. F. velutipes polysaccharides (FVPs) are considered as key bioactive components of F. velutipes, demonstrating multiple physiological activities, including immunomodulatory, anti-inflammatory, and antibacterial properties. Moreover, they offer health benefits such as antioxidant and anti-aging properties, which have exceptionally valuable clinical applications. Polysaccharides derived from different sources exhibit a wide range of biomedical functions and distinct biological activities. The varied biological functions of polysaccharides, coupled with their extensive application in functional foods and clinical applications, have prompted a heightened focus on polysaccharide research. Additionally, the extraction, deproteinization, and purification of FVPs are fundamental to investigate the structure and biological activities of polysaccharides. Therefore, this review provides a comprehensive and systematic overview of the extraction, deproteinization, purification, characterization, and structural elucidation of FVPs. Furthermore, the biological activities and mechanisms of FVPs have been further explored through in vivo and in vitro experiments. This review aims to provide a theoretical foundation and guide future research and development of FVPs.

Homeodomain 1 Genes of the Different HD Subloci of Flammulina velutipes Can Activate the HD Pathway and Are Involved in Mating, Clamp Cell Formation, and Upregulation of FvClp1.

Flammulina velutipes has two independent and functional mating type factors, HD and PR. The HD locus contains two separate subloci: HD-a and HD-b. In this study, we investigated the roles of Hd1 genes of the HD-a and HD-b subloci in the process of mating, clamp cell formation, and regulation of FvClp1 (F. velutipes clampless1 gene) gene expression in F. velutipes. To this end, we introduced Hd1 genes from mating compatible strains into F. velutipes monokaryon L11. Overexpression of Hd1 gene FvHd-a1-1 of the HD-a sublocus resulted in the formation of pseudoclamps in L11 monokaryons. L11 mutants overexpressing the Hd1 gene FvHd-b1-2 of the HD-b sublocus also similarly developed pseudoclamps in the L11 monokaryons. Moreover, these mutant L11 monokaryons produced complete clamps when crossed with monokaryotic strains that differed at the PR loci, i.e., when selective activation of the PR pathway was obtained through crossing. Thus, Hd1 genes of the two different HD subloci in F. velutipes can activate the HD mating type pathway and induce clamp cell formation. In addition, activation of the HD pathway resulted in upregulation of the FvClp1 gene. Finally, to complete clamp cell formation, activation of the PR pathway appears to be essential. Overall, these findings were beneficial for deepening our understanding of sexual reproduction and fruiting body development of edible fungi.

Study on the physicochemical properties and antioxidant activities of Flammulina velutipes polysaccharide under controllable ultrasonic degradation based on artificial neural network.

The polysaccharide fraction (FVP2) with molecular weight of 1525.09 kDa and intrinsic viscosity of 3.43 dL/g was isolated and purified from Flammulina velutipes (F. velutipes), and the ultrasonic degradation model of FVP2 was established to predict the molecular weight and intrinsic viscosity at the same time based on artificial neural network. FVP2U1 (1149.11 kDa, 1.78 dL/g), FVP2U2 (618.91 kDa, 1.19 dL/g) and FVP2U3 (597.35 kDa, 0.48 dL/g) with different molecular weights or viscosity were produced by this model to explore the effect of ultrasound on the physicochemical properties and antioxidant activity of FVP2. The results showed that ultrasonic treatment did not change the types of characteristic functional groups, monosaccharide composition and glycosidic bond of FVP2, but changed the chemical composition ratio and the degree of polymerization. Under ultrasonic treatment, the intrinsic viscosity of FVP2 still decreased significantly when the molecular weight did not decrease. Compared to other components subjected to ultrasonic degradation, FVP2U1 demonstrated higher molecular weight and viscoelasticity, while exhibiting lower antioxidant activity. In the case of no significant difference in molecular weight and monosaccharide composition, FVP2U3 with lower intrinsic viscosity has stronger hydration ability, higher crystallization index, lower viscoelasticity and stronger antioxidant capacity than FVP2U2.

Effects of Flammulina velutipes polysaccharide with ice recrystallization inhibition activity on the quality of beef patties during freeze-thaw cycles: An emphasis on water status and distribution.

The antifreeze activity of Flammulina velutipes polysaccharide (FVP) autoclave-extracted with dilute alkaline and effects of FVP on moisture status, size of ice crystals, physical and chemical characteristics of beef patties during repeated freeze-thaw (F-T) cycles were investigated. Results showed that FVP exhibited ice recrystallization inhibition activity and was able to alter the onset freezing/melting temperature of beef patties. 0.01% FVP significantly alleviated (P < 0.05) the decrement in water holding capacity by inhibiting water migration, restraining the mobility of water, and reducing the size of ice crystals of beef patties during the repeated F-T cycles. In addition, FVP could effectively inhibited oxidation reaction and protein aggregation of beef patties with significant decreases in TBARS value, protein turbidity, contents of total sulfhydryl and carbonyl of myofibrillar protein, and an increase in protein solubility during the repeated cycles. These results suggest FVP could be developed to be a promising cryoprotectant in frozen patties.

In Vitro Assessment of the Antioxidant and Anticancer Properties of Flammulina velutipes Stipe Extracts.

BACKGROUND/AIM: Flammulina velutipes (FV), also known as the golden needle mushroom, is an edible and medicinal fungus that contains bioactive substances regulating various physiological functions. While the fruiting bodies of FV are commonly consumed, their stipes are often discarded despite containing polysaccharides. In this study, the biological functions of FV stipes (FV-S) were investigated to reduce waste and pollution while increasing their value. MATERIALS AND METHODS: The antioxidant activity of FV was evaluated using three methods: the DPPH radical-scavenging capacity assay, ferrous ion chelating assay, and reducing power analysis. The anti-cancer potential was assessed through MTT viability and immunoblotting analyses. RESULTS: Results showed that FV-S had higher polysaccharide and total phenolic contents and greater antioxidant abilities, particularly in ethanolic extracts. FV-S also exhibited significant anticancer properties, specifically in hot water extracts with high polysaccharide contents, and suppressed prostate cancer cell viability by inhibiting androgen receptor and PCa-specific antigen mRNA expression while inducing caspase-3/7 activation. CONCLUSION: FV-S is rich in bioactive components, possesses higher antioxidant and anticancer abilities, and has potential as an anticancer agent, which could enhance the value of FV.

Polysaccharide from Flammulina velutipes residues protects mice from Pb poisoning by activating Akt/GSK3ß/Nrf-2/HO-1 signaling pathway and modulating gut microbiota.

Lead (Pb) can cause damages to the brain, liver, kidney, endocrine and other systems. Flammulina velutipes residues polysaccharide (FVRP) has been reported to exhibit anti-heavy metal toxicity on yeast, but its regulating mechanism is unclear. Therefore, the protective effect and the underlying mechanism of FVRP on Pb-intoxicated mice were investigated. The results showed that FVRP could reduce liver and kidney function indexes, serum inflammatory factor levels, and increase antioxidant enzyme activity of Pb-poisoned mice. FVRP also exhibited a protective effect on histopathological damages in organs of Pb-intoxicated mice. Furthermore, FVRP attenuated Pb-induced kidney injury by inhibiting apoptosis via activating the Akt/GSK3ß/Nrf-2/HO-1 signaling pathway. In addition, based on 16 s rRNA and ITS-2 sequencing data, FVRP regulated the imbalance of gut microbiota to alleviate the damage of Pb-poisoned mice by increasing the abundance of beneficial microbiota (Lachnospiraceae, Lactobacillaceae, Saccharomyces and Mycosphaerella) and decreasing the abundance of harmful microbiota (Muribaculaceae and Pleosporaceae). In conclusion, FVRP inhibited kidney injury in Pb-poisoned mice by inhibiting apoptosis via activating Akt/GSK3ß/Nrf-2/HO-1 signaling pathway, and regulating gut fungi and gut bacteria. This study not only revealed the role of gut fungi in Pb-toxicity, but also laid a theoretical foundation for FVRP as a natural drug against Pb-toxicity.

Flammulina velutipes polysaccharide improves the water-holding capacity in the dorsal muscle of freeze-thawed cultured large yellow croaker (Larimichthys crocea).

To investigate the effect of Flammulina velutipes polysaccharide (FVP) on the water-holding capacity (WHC) in the dorsal muscle of freeze-thawed large yellow croaker, fresh fish were treated with FVP, commercial cryoprotectant (CC), and distilled water before freezing. The water-holding capacity (WHC) and related influencing factors were analyzed. The results showed that FVP was able to effectively improve the WHC by reducing thawing loss and cooking loss, and the effect was similar to that of the CC group. Smaller and rounder ice crystals and less damaged muscle tissue were observed in FVPs. FVP also significantly retarded the protein denaturation revealed by Ca2+-ATPase activity, ultraviolet-visible absorption spectra, and SDS-PAGE of the myofibrillar protein. Furthermore, protein oxidation was inhibited by FVP treatment, as demonstrated by the sulfhydryl group and intrinsic fluorescence intensity. In summary, FVP can effectively improve the WHC by inhibiting the growth of ice crystals, protein denaturation, and potentially protein oxidation.

Biosynthesis of gold nanoparticles in the fruiting body of enoki mushrooms (Flammulina velutipes) under Pb2+ induction.

Fungi can produce many compounds, such as proteins, enzymes, amino acids, and polysaccharides, which are internalised and enriched for metals, and are widely used as reducing and stabilising agents for the biosynthesis of gold nanoparticles (Au NPs). Almost all fungal sources used in the synthesis of the Au NPs are in the form of cell filtrates or mycelial suspensions. However, the culture of cell-free fungal filtrate and mycelium is not comparable to the propagation of fungal substrates in input and operation. Here, we evaluated in vivo biosynthesis of Au NPs in enoki mushrooms (Flammulina velutipes). HAuCl4 was reduced in the fruiting body of the enoki mushrooms via induction by Pb2+ , resulting in the generation of Au NPs. We then employed UV-Vis absorption spectroscopy, Transmission Electron Microscope, and Energy Dispersive Spectrometer to characterise various shapes of the Au NPs. The elemental analysis indicated that the Au NPs were mainly concentrated in organelles of the stalk and cap cells. We also demonstrated that 0.3-0.5 mM HAuCl4 was the optimal stress treatment concentration based on the changes in physiological indicators of the enoki mushrooms. This work reveals that fungi can be utilised well as nanomaterial bioreactors.

Flammulina velutipes Mycorrhizae Attenuate High Fat Diet-Induced Lipid Disorder, Oxidative Stress and Inflammation in the Liver and Perirenal Adipose Tissue of Mice.

Flammulina velutipes (FV) is edible mushroom that has nutritional and medicinal values. FV mycorrhizae, the by-products of FV, are an abundant source and receive less attention. The objective of this study was to investigate the composition of FV mycorrhizae, and its effects on high fat diet (HFD)-induced lipid disorder, oxidative stress, and inflammatory cytokines, both in the liver and perirenal adipose tissue (PAT) of mice. The results showed that FV mycorrhizae contain abundant trace elements, polysaccharide, amino acids and derivatives, and organic compounds. It was found that 4% FV mycorrhizae (HFDFV) supplementation decreased HFD-induced liver weight and triglyceride (TG) in the plasma, liver and PAT, altered plasma and hepatic fatty acids profiles, promoted gene expression involved in lipid hydrolysis, fatty acid transportation and ß-oxidation in the liver and reduced lipid synthesis in the liver and PAT. HFDFV attenuated HFD-induced oxidative stress and pro-inflammatory cytokine by increasing GSH/GSSG, and decreasing levels of MDA and IL6 both in the liver and PAT, while it differentially regulated gene expression of IL1ß, IL6, and CCL2 in liver and PAT. The results indicated that FV mycorrhizae are effective to attenuate HFD-induced lipid disorder, oxidative stress and inflammation in the liver and PAT, indicating their promising constituents for functional foods and herbal medicine.

Residues of Culinary-Medicinal Winter Mushroom, Flammulina velutipes (Agaricomycetes), Cultivation as a Potential Source of Functional Skin Substitute with Multiple Bioactivities.

Residues generated during the cultivation of edible mushroom Flammulina velutipes are abundant and utilized with low efficiency. In this study, the composition and bioactivities of a skin substitute named TG05 obtained from residues of the F. velutipes cultivation process were investigated. The main composition of TG05 was considered to be chitin and it inhibited growth of Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. TG05 also suppressed the inflammatory response through the inducible nitric oxide synthase signaling pathway. Inflammation was attenuated by reducing the expression of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and prostaglandin E2 at the transcription level. Furthermore, TG05 exhibited antioxidant activities based on hydroxyl, 2,2-diphenyl-1-picryl-hydrazy, 2,2'-azobis-(3-ethylbenzothiazoline-6-sulfonic acid), superoxide anion radical scavenging activity, and reducing power assays. However, the effect of TG05 was independent of hyaluronidase inhibitory activity. Taken together, specific mechanisms related to the notable wound-healing-promoting activity of TG05 were demonstrated, mainly attributable to its antimicrobial, anti-inflammatory, and antioxidant activities. Therefore, TG05 may have potential for use as a functional biomaterial in various applications.

The structure-activity mechanism of the changes in the physicochemical properties of Flammulina velutipes polysaccharides during ultrasonic extraction.

BACKGROUND: The high yield of ultrasonic extraction has been widely studied. However, the effects of ultrasound on the properties of products has generally been ignored. In this study, the structural characteristics, rheological properties, and thermal stability of Flammulina velutipes polysaccharides (FVPs) under different ultrasonic power (200, 600, 1000 W) and time (10, 20, 30 min) were investigated to explore the effects of ultrasonic extraction on FVPs and the structure-physicochemical properties relationship. The ultrasonic intensity at the corresponding rated power was also measured. RESULTS: The results showed that the molecular weight, particle size, and zeta potential of FVPs decreased as the ultrasonic intensity or time increased. The galactose, mannose, and fucose contents were increased, but the glucose content was decreased by ultrasonic extraction. Viscosity and weak gel strength were positively correlated with molecular weight. Thermal degradation enthalpy was positively correlated with the galactose and fucose contents. CONCLUSIONS: Ultrasound reduced the viscosity and gel strength of FVPs by breaking the polysaccharide chain and improving the galactose and fucose contents, which improved the thermal stability of FVPs. This work provides a theoretical basis for the development of FVP foods with a clear structure-function relationship, which makes it possible to directionally produce FVPs by adjusting ultrasonic parameters during extraction. © 2021 Society of Chemical Industry.

Characterization, Antioxidant and Anti-Inflammation Capacities of Fermented Flammulina velutipes Polyphenols.

This work investigated the preparation, characterization, antioxidant, and anti-inflammation capacities of Flammulina velutipes polyphenols (FVP) and fermented FVP (FFVP). The results revealed that the new syringic acid, accounting for 22.22%, was obtained after fermentation (FFVP). FFVP exhibits higher antioxidant and anti-inflammation activities than FVP, enhancing cell viability and phagocytosis, inhibiting the secretion of NO and ROS, and reducing the inflammatory response of RAW264.7 cells. This study revealed that FFVP provides a theoretical reference for in-depth study of its regulatory mechanisms and further development of functional antioxidants that are applicable in the food and health industry.

Isolation, characterization and HepG-2 inhibition of a novel proteoglycan from Flammulina velutipes.

Flammulina velutipes has anti-inflammatory, immunomodulatory, antioxidant and many bioactive properties with high contents of carbohydrate, proteins and fibers. In this study, a novel proteoglycan with polysaccharide complexes and protein chain, named PGD1-1, was isolated from F. velutipes. The structural characteristics of PGD1-1 were then determined, and its anti-proliferation and pro-apoptotic activities against HepG-2 cells were demonstrated in vitro. Results proved that the average molecular weight of PGD1-1 was 32.71 kDa, and the carbohydrate and protein contents were 93.35 and 2.33%, respectively. The protein moiety was bonded to a polysaccharide chain via O-glycosidic linkage. The monosaccharides consisted of d-glucose, D-galactose and D-xylose in a molar ratio of 21.90:2.84:1.00. PGD1-1 significantly inhibited the proliferation of HepG-2 cells by affecting cell lipid peroxidation and nitric oxide production. In addition, PGD1-1 promoted the apoptosis of HepG-2 cells, especially the early apoptosis. These findings proved that PGD1-1 was a novel potent ingredient against the proliferation of HepG-2, which will provide a theoretical basis for the development and utilization of the functional ingredients of the F. velutipes.

The biological regulatory activities of Flammulina velutipes polysaccharide in mice intestinal microbiota, immune repertoire and heart transcriptome.

The effects of a novel Flammulina velutipes polysaccharide (FVP) on intestinal microbiota, immune repertoire and heart transcriptome were investigated in this study. The results showed that FVP treatment could effectively regulate the abundance of colonic microbiota. And FVP exhibited obvious immunoregulatory effect by influencing V gene and J gene fragments usage on TCRα chain. The usage frequency of TRBV1, TRBJ1-6 and TRBJ1-5 were significantly altered, and 41 V-J pairs were identified with obvious difference after FVP treatment. Furthermore, the mRNA of mice heart was analyzed by transcriptome assay. Total 525 genes and 1587 mRNA were significantly changed after FVP treatment. KEGG annotation indicated that the up-regulated mRNA was enriched in 17 pathways including adherens junction, mTOR signaling pathway, insulin signaling pathway, mitophagy, tight junction, PPAR signaling pathway and TNF signaling pathway, etc. Meanwhile, the down-regulated mRNA was gathered in AMPK signaling pathway, metabolism of xenobiotics by cytochrome P450, apelin signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, insulin signaling pathway, cardiac muscle contraction, adrenergic signaling in cardiomyocytes, Fc gamma R-mediated phagocytosis, etc. The great potential exhibited by FVP could make it an ideal candidate as complementary medicine or functional food for promotion of health.

Characterization of insoluble dietary fiber from three food sources and their potential hypoglycemic and hypolipidemic effects.

Dietary fiber is an important nutrient for improving human health and controlling calorie intake, and is used to produce functional foods. In this study, insoluble dietary fiber (IDF) from three sources (enoki mushrooms, carrots, and oats) was characterized and their hypoglycemic and hypolipidemic effects were determined with in vitro and in vivo models. The results of Scanning electron microscopy (SEM) showed that the IDF from the three sources have different morphologies. The Fourier transform infrared spectroscopy (FT-IR) results showed that the IDF samples from the three sources have similar active groups, but the X-ray diffraction (XRD) and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) results indicated that oat IDF mainly contained cellulose, and enoki mushroom IDF and carrot IDF contained hemicelluloses and cellulose. Among three IDF, carrot IDF had stronger water holding capacity, swelling capacity, and adsorption capacity of oil and cholate; enoki mushroom IDF had stronger glucose adsorption capacity and the ability to inhibit fat digestion; while oat IDF had stronger cholesterol adsorption capacity. None of the three IDF showed significant inhibition on starch digestion. Results from mouse feeding studies showed that IDF from three sources all improved glucose tolerance and inhibited the rise of blood lipid after the fat loading. Thus, this study demonstrated the functional significance of the IDF from three sources, which provides a reference for their application in functional food products aiming at maintaining healthy glucose and blood lipid levels.

Polysaccharide from Flammulina velutipes attenuates markers of metabolic syndrome by modulating the gut microbiota and lipid metabolism in high fat diet-fed mice.

Natural biological macromolecules with putative functions of gut microbiota regulation possess the advantage of improving metabolic syndrome (MS). In this research, we aimed to determine the effects of Flammulina velutipes polysaccharide (FVP) (Expt. 1) and fecal microbiota transplantation (FMT) (Expt. 2) on MS-related disorders, gut microbiota structure changes and their underlying mechanisms in a murine model fed with high-fat diet (HFD). In Expt. 1, six-week-old male C57BL/6J mice were fed with a control diet (10% calories from fat) or a high fat diet (45% calories from fat), administered with saline or FVP (0.4 mg per g b.w.) by gavage over a 12-week period. In Expt. 2, mice were fed with a HFD, administered with fecal supernatants from healthy and FVP-fed donor mice for 12 weeks simultaneously. The body mass, blood lipid levels and blood glucose homeostasis of mice were analyzed, and total RNA from mouse liver and adipose tissue were extracted by TRIzol and the lipid metabolism-related gene expressions were calculated by qRT-PCR. Gut microbiota changes were evaluated by high-throughput sequencing. Results indicated that FVP and FMT supplementations showed an attenuation effect on mouse obesity, hyperlipidemia and insulin resistance. Up-regulated expressions of Ampkα1 and Ppara were found both in FVP and FMT treatment groups. Different changes were found in the gut microbiota caused by FVP and FMT, respectively. PICRUSt analysis indicated that compared with FVP supplementation, FMT showed a significant effect on regulating lipid metabolism in HFD-fed mice. The findings from this study indicated that oral administrations of FVP or FMT could significantly attenuate MS-related obesity, hyperlipidemia and insulin resistance in HFD-fed mice, and the beneficial effects may be mediated through lipid metabolism and gut microbiota regulation in different ways. These results improve the understanding of the functional activity of FVP as prebiotics.