Polysaccharides from Agaricus blazei Murrill ameliorate dextran sulfate sodium-induced colitis via attenuating intestinal barrier dysfunction

Polysaccharide from Boletus aereus ameliorates DSS-induced colitis in mice by regulating the MANF/MUC2 signaling and gut microbiota

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions characterized by disruptions in the colonic mucus barrier and gut microbiota. In this study, a novel soluble polysaccharide obtained from Boletus aereus (BAP) through water extraction was examined for its structure. The protective effects of BAP on colitis were investigated using a DSS-induced mice model. BAP was found to promote the expression of intestinal mucosal and tight junction proteins, restore the compromised mucus barrier, and suppress the activation of inflammatory signaling. Moreover, BAP reshape the gut microbiota and had a positive impact on the composition of the gut microbiota by reducing inflammation-related microbes. Additionally, BAP decreased cytokine levels through the MANF-BATF2 signaling pathway. Correlation analysis revealed that MANF was negatively correlated with the DAI and the level of cytokines. Furthermore, the depletion of gut microbiota using antibiotic partially inhabited the effect of BAP on the activation of MANF and Muc2, indicating the role of gut microbiota in its protective effect against colitis. In conclusion, BAP had an obvious activation on MANF under gut inflammation. This provides new insights into the prospective use of BAP as a functional food to enhance intestinal health.

Polysaccharide Isolated from Agaricus blazei Murill Alleviates Intestinal Ischemia/Reperfusion Injury through Regulating Gut Microbiota and Mitigating Inflammation in Mice

Intestinal ischemia-reperfusion (I/R) injury is a serious disease in medical settings, and gut dysbiosis is a major contributor to its development. Polysaccharides from Agaricus blazei Murill (ABM) showed a range of pharmacological activities, yet no studies assessed the potential of ABM polysaccharides for alleviating intestinal I/R injury. Here, we purified a major polysaccharide (ABP1) from an ABM fruit body and subsequently tested its potential to mitigate intestinal I/R injury in a mouse model of temporary superior mesenteric artery occlusion. The results reveal that ABP1 pretreatment enhances gut barrier function via upregulation of the expression of tight junction proteins such as ZO-1 and occludin. Additionally, ABP1 intervention reduces the recruitment of neutrophils and the polarization of M1 macrophages and limits inflammation by blocking the assembly of the NLRP3 inflammasome. Moreover, the role of ABP1 in regulating the gut microbiota was confirmed via antibiotic treatment. The omics data reveals that ABP1 reprograms gut microbiota compositions, characterized by a decrease of Proteobacteria and an increase of Lachnospiraceae and Lactobacillaceae, especially the SCFA-producing genera such as Ligilactobacillus and Blautia. Overall, this work highlights the therapeutic potential of ABP1 against intestinal I/R injury, which mainly exhibits its effects via regulating the gut microbiota and suppressing the overactivated inflammation response.

Effect of polysaccharides on conformational changes and functional properties of protein-polyphenol binary complexes: A comparative study

This study aimed to investigate the effect of different polysaccharides on the binding behavior and functional properties of soybean protein isolate (SPI)-quercetin (Que) complex. The binding behavior was assessed using multi-spectral technique with the Stern-Volmer equation, which confirmed the presence of static fluorescence quenching in Que and SPI. The addition of sodium alginate (SA) resulted in a reduction of the binding affinity between SPI and Que, while dextran (DX) exhibited some promoting effect. A slight blue shift was observed in amide I and amide II bands, indicating the presence of hydrophobic and electrostatic interactions. Circular dichroism spectra revealed the ordered structures transformed into a more disordered state when polysaccharides were added, leading to an increase in random coils (SA: 18.5 %, DX: 15.4 %). Docking and dynamic simulations demonstrated that SA displayed greater stability within the hydrophobic compartments of SPI than DX, increased rigidity and stability of the SPI structure in SPI-Que-SA complexes. Electrostatic forces played a significant role between SPI and SA, while van der Waals forces were the main driving forces in SPI-DX complexes. Overall, the introduction of SA led to a looser and stable structure of SPI-Que complexes, resulting in an improvement of their emulsifying, foaming, and antioxidant properties.

Agaricus blazei Polysaccharide Alleviates DSS-Induced Colitis in Mice by Modulating Intestinal Barrier and Remodeling Metabolism

Ulcerative colitis (UC) is a chronic noninfectious intestinal disease that severely affects patients' quality of life. Agaricus blazei Murrill polysaccharide (ABP) is an effective active ingredient extracted from Agaricus blazei Murrill (ABM). It has good efficacy in inhibiting tumor cell growth, lowering blood pressure, and improving atherosclerosis. However, its effect on colitis is unclear. The aim of this study was to analyze the protective effects and potential mechanisms of ABP against dextran sulfate sodium (DSS)-induced acute colitis in mice. The results showed that dietary supplementation with ABP significantly alleviated DSS-induced colitis symptoms, inflammatory responses, and oxidative stress. Meanwhile, ABP intervention was able to maintain the integrity of the intestinal mechanical barrier by promoting the expression of ZO-1 and Occludin tight junction proteins and facilitating mucus secretion. Moreover, 16S rRNA sequencing results suggested that ABP intervention was able to alleviate DSS-induced gut microbiota disruption, and nontargeted metabolomics results indicated that ABP was able to remodel metabolism. In conclusion, these results demonstrate that dietary supplementation with ABP alleviated DSS-induced acute colitis by maintaining intestinal barrier integrity and remodeling metabolism. These results improve our understanding of ABP function and provide a theoretical basis for the use of dietary supplementation with ABP for the prevention of ulcerative colitis.

Longan Polysaccharides with Covalent Selenylation Combat the Fumonisin B1-Induced Cell Toxicity and Barrier Disruption in Intestinal Epithelial (IEC-6) Cells

In this study, the soluble, but non-digestible, longan (Dimocarpus longan Lour.) polysaccharides (LP) were extracted from dried longan fruits and then chemically selenylated to produce two selenylated products, namely SeLP1 and SeLP2, with different selenylation extents. The aim was to investigate their protective effects on rat intestinal epithelial (IEC-6) cells exposed to the food toxin fumonisin B1 (FB1). LP only contained total Se content of less than 0.01 g/kg, while SeLP1 and SeLP2 were measured with respective total Se content of up to 1.46 and 4.79 g/kg. The cell viability results showed that these two selenylated products were more efficient than LP in the IEC-6 cells in alleviating FB1-induced cell toxicity, suppressing lactate dehydrogenase (LDH) release, and decreasing the generation of intracellular reactive oxygen species (ROS). These two selenylated products were also more effective than LP in combating FB1-induced barrier disruption via increasing the transepithelial electric resistance (TEER), reducing the paracellular permeability, decreasing the mitochondrial membrane potential (MMP) loss, and maintaining cell barrier integrity by upregulating the tight-junction-related genes and proteins. FB1 caused cell oxidative stress and barrier dysfunction by activating the MAPK and mitochondrial apoptosis signaling pathways, while SeLP1 and SeLP2 could regulate the tMAPK- and apoptosis-related proteins to suppress the FB1-mediated activation of the two pathways. Overall, SeLP2 was observed to be more active than SeLP1 in the IEC-6 cells. In conclusion, the chemical selenylation of LP caused an activity enhancement to ameliorate the FB1-induced cell cytotoxicity and intestinal barrier disruption. Meanwhile, the increased selenylation of LP would endow the selenylated product SeLP2 with more activity.

Sea Cucumber Peptide Alleviates Ulcerative Colitis Induced by Dextran Sulfate Sodium by Alleviating Gut Microbiota Imbalance and Regulating miR-155/SOCS1 Axis in Mice

Sea cucumber peptides have been proven to exhibit a variety of biological activities. Ulcerative colitis (UC) is a chronic disease characterized by diffuse inflammation of the mucosa of the rectum and colon with increasing incidence and long duration, and is difficult to cure. The effect of sea cucumber peptide on UC is currently unknown. In this study, 1.5% dextran sulfate sodium (DSS) was added to the drinking water of mice to induce a UC model, and the daily doses of sea cucumber peptide (SP) solution of 200 mg/kg·BW, 500 mg/kg·BW, and 1000 mg/kg·BW were given to UC mice to detect the relieving effect of SP. The results showed that SP can reduce the disease activity index (DAI) of UC mice induced by DSS and can alleviate colon shortening, intestinal tissue damage, and the loss of intestinal tight junction proteins (Claudin-1, Occludin). SP decreased the spleen index, pro-inflammatory factors (IL-1β, IL-6, TNF-α), and myeloperoxidase (MPO) levels in UC mice. SP can alleviate the imbalance of gut microbiota in UC mice, increase the abundance of the Lachnospiraceae NK4A136 group, Prevotellaceae UCG-001, and Ligilactobacillus, and reduce the abundance of Bacteroides and the Eubacterium rum group, as well as alleviating the decrease in short-chain fatty acid (SCFA) content in the feces of UC mice. Notably, SP inhibited miR-155 expression in the colon tissue of UC mice and increased its target protein, suppressor of cytokine signaling 1 (SOCS1), which acts as an inflammatory inhibitor. In summary, the ameliorative effect of SP on UC may be achieved by improving the imbalance of gut microbiota and regulating the miR-155/SOCS1 axis. This study provides a new idea for developing SP as a nutritional supplement to maintain intestinal health.

Ganoderma lucidum polysaccharide peptides GL-PPSQ2 alleviate intestinal ischemia-reperfusion injury via inhibiting cytotoxic neutrophil extracellular traps

Ganoderma lucidum polysaccharides peptides (GLPP) are the main effective ingredients from G. lucidum (Leyss. ex Fr.) Karst with anti-inflammatory, antioxidant, and immunoregulatory activities. We extracted and characterized a novel GLPP, named GL-PPSQ₂, which were found to have 18 amino acids and 48 proteins, connected by O-glycosidic bonds. The monosaccharide composition of GL-PPSQ₂ was determined to be composed of fucose, mannose, galactose and glucose with a molar ratio of 1: 1.45:2.37:16.46. By using asymmetric field-flow separation technique, GL-PPSQ₂ were found to have a highly branched structure. Moreover, in an intestinal ischemia-reperfusion (I/R) mouse model, GL-PPSQ₂ significantly increased the survival rate and alleviated intestinal mucosal hemorrhage, pulmonary permeability, and pulmonary edema. Meanwhile, GL-PPSQ₂ significantly promoted intestinal tight junction, decreased inflammation, oxidative stress and cellular apoptosis in the ileum and lung. Analysis with Gene Expression Omnibus series indicates that neutrophil extracellular trap (NET) formation plays an important role in intestinal I/R injury. GL-PPSQ₂ remarkedly inhibited NETs-related protein myeloperoxidase (MPO) and citrulline-Histone H3 (citH3) expression. GL-PPSQ₂ could alleviate intestinal I/R and its induced lung injury via inhibiting oxidative stress, inflammation, cellular apoptosis, and cytotoxic NETs formation. This study proves that GL-PPSQ₂ is a novel drug candidate for preventing and treating intestinal I/R injury.

Pentacyclic triterpene-loaded emulsion stabilized by Agaricus blazei Murill polysaccharides: Factorial design and cytoprotection study

In this study, pentacyclic triterpene-loaded emulsions were stabilized by polysaccharides from Agaricus blazei Murill mushroom (PAb). The drug-excipient compatibility results by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) showed the absence of physicochemical incompatibilities. The use of these biopolymers at 0.75 % led to obtaining emulsions with droplets smaller than 300 nm, moderate polydispersity, and ζ-potential >30 mV in modulus. The emulsions presented high encapsulation efficiency, suitable pH for topical application, and absence of macroscopic signs of instability during 45 days. Morphological analysis suggested the deposition of thin layers of PAb around the droplets. The encapsulation of pentacyclic triterpene in emulsions, stabilized by PAb, improved the cytocompatibility of this drug against PC12 and murine astrocyte cells. There was a reduction in cytotoxicity, which resulted in a lower accumulation of intracellular reactive oxygen species and maintenance of the mitochondrial transmembrane potential. Based on these results, it is estimated that PAb are promising biopolymers for the emulsions' stabilization by improving their physicochemical and biological properties.

The Barrier-Enhancing Function of Soluble Yam (Dioscorea opposita Thunb.) Polysaccharides in Rat Intestinal Epithelial Cells, as Affected by the Covalent Se Conjugation

The non-starch yam polysaccharides (YP) are the bioactive substances of edible yam, while Se is an essential nutrient for the human body. Whether a covalent conjugation of Se to YP might cause bioactivity change for the resultant selenylated YP in the intestine is still insufficiently studied, including the critical intestinal barrier function. In this study, two selenylated YP products, namely, YPSe-I and YPSe-II, with corresponding Se contents of 795 and 1480 mg/kg, were obtained by the reaction of YP and Na2SeO3 in the presence of HNO3 and then assessed for their bioactivities to a cell model (i.e., rat intestinal epithelial IEC-6 cells). The results showed that YP, YPSe-I, and YPSe-II at 5–80 μg/mL dosages could promote cell growth with treatment times of 12–24 h. The three samples also could improve barrier integrity via increasing cell monolayer resistance and anti-bacterial activity against E. coli or by reducing paracellular permeability and bacterial translocation. Additionally, the three samples enhanced F-actin distribution and promoted the expression of the three tight junction proteins, namely, zonula occluden-1, occludin, and claudin-1. Meanwhile, the expression levels of ROCK and RhoA, two critical proteins in the ROCK/RhoA singling pathway, were down-regulated by these samples. Collectively, YPSe-I and, especially, YPSe-II were more potent than YP in enhancing the assessed bioactivities. It is thus concluded that this chemical selenylation of YP brought about enhanced activity in the cells to promote barrier integrity, while a higher selenylation extent of the selenylated YP induced much activity enhancement. Collectively, the results highlighted the important role of the non-metal nutrient Se in the modified polysaccharides.