Microbiome-metabolomics analysis insight into the effects of dietary resistant starch on intestinal integrity.

Resistant starch (RS) has caught much attention for its potential to exert a beneficial impact on intestine and certain members of its resident microbiota. In this study, we examined how dietary RS promotes intestinal barrier in meat ducks by microbiome-metabolomics analysis. Ducklings were fed corn-soybean basal diet or RS diet. Dietary RS improved intestinal morphology and enhanced barrier function in ileum, evidenced by lower permeability and upregulated tight junction proteins and Mucin-2 gene expression. Microbiome analysis showed that RS administration elevated the proportion of Firmicutes and butyrate-producing bacteria, and increased butyrate contents in cecum. Furthermore, significant alterations in metabolic profiles were observed, with most of these were associated with the amino acid metabolism (especially tryptophan), lipid metabolism, and intestinal inflammation. Together, diet with RS improved gut integrity and caused corresponding alterations in gut metabolome and microbiome, yielding better insights of the mechanism by RS improved the gut system of ducks.

[Experimental study on effects of berberine combined with 6-shogaol on intestinal inflammation and flora in mice with ulcerative colitis].

Cold-heat combination is a common method in the treatment of ulcerative colitis, which is represented by classic drug pair, Coptidis Rhizoma and Zingiberis Rhizoma.The present study explored the synergetic effects of berberine and 6-shogaol, the primary components of Coptidis Rhizoma and Zingiberis Rhizoma, respectively, on intestinal inflammation and intestinal flora in mice with ulcerative colitis to reveal the effect and mechanism of cold-heat combination in the treatment of ulcerative colitis.The ulcerative colitis model was induced by dextran sulfate sodium(DSS) in mice.The model mice were administered with berberine(100 mg·kg~(-1)), 6-shogaol(100 mg·kg~(-1)), and berberine(50 mg·kg~(-1)) combined 6-shogaol(50 mg·kg~(-1)) by gavage, once per day.After 20 days of drug administration, mouse serum, colon tissues, and feces were sampled.Hematoxylin-eosin(HE) staining was used to observe histopathological changes in colon tissues.Alcian blue/periodic acid-Schiff(AB/PAS) staining was used to observe the changes in the mucus layer of colon tissues.Enzyme-linked immunosorbent assay(ELISA) was employed to detect the serum content of tumor necrosis factor-α(TNF-α), interleukin-1ß(IL-1ß), and interleukin-6(IL-6).Immunohistochemical method was adopted to detect the protein expression of macrophage surface markers F4/80, mucin-2, claudin-1, and zonula occludens-1(ZO-1) in colon tissues.High-throughput Meta-amplicon library sequencing was used to detect changes in the intestinal flora of mice.The results indicated that the 6-shogaol group, the berberine group, and the combination group showed significantly relieved intestinal injury, reduced number of F4/80-labeled positive macrophages in colon tissues, increased protein expression of mucin-2, claudin-1, and ZO-1, and decreased serum le-vels of TNF-α, IL-1ß, and IL-6.Shannon, Simpson, Chao, and Ace indexes of the intestinal flora of mice in the 6-shogaol group and the combination group significantly increased, and Chao and Ace indexes in the berberine group significantly increased.As revealed by the bioinformatics analysis of intestinal flora sequencing, the relative abundance of Verrucomicrobia at the phylum, class, and order levels decreased significantly in all treatment groups after drug administration, while that of Bacillibacteria gradually increased.In the 6-shogaol group and the combination group, Akkermansia muciniphila completely disappeared, but acid-producing bacillus still existed in large quantities.As concluded, both 6-shogaol and berberine can inhibit intestinal inflammation, reduce the infiltration and activation of macrophages, relieve intestinal damage, reduce intestinal permeability, improve the structure of flora, and promote intestinal microecological balance.The combined application of berberine and 6-shogaol has a significant synergistic effect.

Lactobacillus paracasei from koumiss ameliorates diarrhea in mice via tight junctions modulation.

OBJECTIVES: Probiotics are gaining interest as alternative options for antibiotic or antiinflammatory drugs. Probiotics can affect the health of the host through metabolites and competitive inhibition adhesion of pathogenic microorganisms. Koumiss is an important part of the diet of Asian nomads, and is rich in a broad array of probiotics that can benefit the body. Mongolians have developed koumiss therapy to assist in the treatment of various diseases. In the present study, we investigate the beneficial effect of Lactobacillus paracasei, a strain isolated from koumiss, on a mouse model of diarrhea induced by Escherichia coli O8 (E. coli O8). METHODS: Probiotics were isolated from Mongolian koumiss. The resistance of probiotics against acid, bile salts, gastric juice, and intestinal juice was evaluated. The mouse model of diarrhea was established by the intragastric administration of E. coli O8 after NaHCO3 treatment. L. paracasei was intragastrically administered before or after E. coli O8 exposure in mice. The plasma levels of diamine oxidase and zounlin were quantified using an enzyme-linked immunosorbent assay, and the integrity of the intestinal barrier and goblet cells of mice with diarrhea were observed using hematoxylin and eosin and Alcian blue periodic acid-Schiff staining. The expression of tight junction (TJ) proteins was detected by immunohistochemistry and Western blot. RESULTS: A total of five lactic acid bacteria and two yeast strains were isolated from koumiss, and L. paracasei was screened for animal experiments. Experimental results showed that L. paracasei could reduce the increase in diamine oxidase and zonulin caused by E. coli (P < 0.05); increase goblet cells and the expression of TJ proteins ZO-1, occludin, and claudin-1 (P < 0.05); increase the expression of mucin 2, oligomeric mucus/gel-forming (P < 0.05) protein; and reduce the level of inhibitor kappa B-alpha and myosin light-chain kinase. CONCLUSIONS: L. paracasei reduced the intestinal permeability, induced the expression of mucin 2, oligomeric mucus/gel-forming protein, and increased the number of goblet cells in mice by the upregulation of the expression of TJ proteins via the nuclear factor kappa B cells-myosin light-chain kinase signaling pathway.

Deficiency of intestinal mucin-2 protects mice from diet-induced fatty liver disease and obesity.

Nonalcoholic fatty liver disease (NAFLD) and obesity are characterized by altered gut microbiota, inflammation, and gut barrier dysfunction. Here, we investigated the role of mucin-2 (Muc2) as the major component of the intestinal mucus layer in the development of fatty liver disease and obesity. We studied experimental fatty liver disease and obesity induced by feeding wild-type and Muc2-knockout mice a high-fat diet (HFD) for 16 wk. Muc2 deficiency protected mice from HFD-induced fatty liver disease and obesity. Compared with wild-type mice, after a 16-wk HFD, Muc2-knockout mice exhibited better glucose homeostasis, reduced inflammation, and upregulated expression of genes involved in lipolysis and fatty acid ß-oxidation in white adipose tissue. Compared with wild-type mice that were fed the HFD as well, Muc2-knockout mice also displayed higher intestinal and plasma levels of IL-22 and higher intestinal levels of the IL-22 target genes Reg3b and Reg3g. Our findings indicate that absence of the intestinal mucus layer activates the mucosal immune system. Higher IL-22 levels protect mice from diet-induced features of the metabolic syndrome.

The role of salivary proteins in the mechanism of astringency.

Understanding astringency has focused on the interaction of tannins with the salivary proline-rich proteins (PRPs), although it remains unclear if other astringents precipitate the PRPs or how this interaction relates to sensory perceptions of astringency. We used 2 approaches to compare how distinct classes of astringent compounds interacted with the salivary PRPs and mucins. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis, we evaluated protein patterns and characterized the salivary proteins present in the supernatants and pellets of pooled saliva assayed with tannin, alum, and hydrochloric acid solutions. Tannins and alum precipitated many of the PRPs, but acid did not. Mucins were precipitated by both the acid and alum, but not by the tannins. From our research, it appears that the precipitation of salivary proteins may be involved in the mechanism of astringency, but the precipitation of PRPs is not requisite for the development of astringency. We also measured mucin and deoxyribonucleic acid content of expectorated solutions of astringents that panelists swished in their mouths to determine if astringency was associated with a loss of oral lubricating films.

Mucin-induced apoptosis of monocyte-derived dendritic cells during maturation.

Many tumors arising from epithelial tissues produce mucins, which readily come into contact with infiltrating cells in cancer tissues. MUC2 mucins were purified from the conditioned medium of a colorectal cancer cell line, LS180 cells. It is known that in cancer patients, the number of dendritic cells (DCs) is reduced and their function is impaired. Mature DCs were generated from human peripheral blood monocytes through successive treatments with GM-CSF and IL-4, and then with proinflammatory mediators. When monocytes were cultured in the presence of MUC2 mucins in addition to GM-CSF and IL-4 at an early stage of development, mature DCs expressing CD83 decreased and apoptotic cells increased in a dose-dependent manner. During the development of DCs, sialic acid-binding Ig-like lectin (Siglec)-3 was constantly expressed. We prepared recombinant soluble Siglec-3 corresponding to the ectodomain of Siglec-3 and confirmed the binding of soluble Siglec-3 to the MUC2 mucins, probably through alpha2,6-sialic acid-containing O-glycans including a sialyl Tn antigen, which is known to bind to Siglec-3. Apoptosis was partially inhibited by anti-Siglec-3 mAb or recombinant soluble Siglec-3. These results suggest that apoptosis was partially induced through the ligation of the MUC2 mucins with Siglec-3.