Akermansia muciniphila shows promise as a next-generation probiotic, however, its beneficial regulatory effects on mice ulcerative colitis (UC) has not been extensively investigated. We used an Akkermansia muciniphila strain (AKK ONE) isolated from healthy human feces to study its effect on DSS-induced colitis in mice. Our results demonstrate that AKK ONE supplementation significantly improves food intake, weight, colon length, disease activity index (DAI) score, organ index, and tissue damage of colitis mice. AKK ONE notably improved intestinal barrier integrity by significantly enhancing expression of occludin and claudin-1. Additionally, AKK ONE reduced inflammation by down-regulating IL-1β, IL-6, and TNF-α, and up-regulating IL-10. In addition to reducing excessive inflammation, AKK ONE also increased the abundance of Akkermansia and decreased the abundance of Bacteroides. Furthermore, the AKK ONE intervention markedly increased SCFAs in cecal contents. AKK ONE may be a potential therapeutic agent for improving UC, based on the findings of this study.

Objective. Lactic acid bacteria (LAB) were isolated from fermented foods, such as glutinous rice dough, corn noodle, chili sauce, potherb mustard pickles, and stinky tofu, in northeast China. LAB strains with antimicrobial activities were screened, and seven of these Lactobacillus strains were identified as L. plantarum, L. pentosus, and L. paracasei through 16S rRNA gene analysis. After the supernatant of LAB was treated with proteinase K, pepsin, and papain, their antibacterial effect almost disappeared. Most strains with antibacterial activities were highly resistant to heat (65°C–121°C), acidity (pH 2–6), and alcohol. The antimicrobial effect of most strains treated with the Tween-80 surfactant was significantly reduced, and the antibacterial property of T4 was even lost. Ammonium sulfate precipitation, PCR, and nanoLC-ESI-MS/MS results confirmed that T8 produced antibacterial substances belonging to a protein family, and its zone of inhibition against pathogens significantly increased (>13 mm). In bacterial growth inhibition experiments, the colony count of Staphylococcus aureus was up to 10¹⁵ CFU/mL in the 3⁎de Man, Rogosa, and Sharpe (MRS) group, and this value was more than that in the 3⁎S6 supernatant group (10¹² CFU/mL) and the control group (10¹⁰ CFU/mL) at 12 h. This study provided a basis for the selection of antimicrobial peptides and the development and utilization of LAB.

Evidence suggests that probiotic interventions reduce non-communicable diseases (NCDs) risk. However, its therapeutic effect and mechanism are still unclear. To evaluate the hypocholesterolemic effect of Lactobacillus plantarum H6 (L.p H6), a new commercial patent strain capable of preventing hypercholesterolemia, and its mechanism in depth, three states of the strain were prepared, namely, viable (vH6), heat-inactivated (iH6), and ultrasonically-lysed (uH6) bacteria cells. The results showed that v/i/uH6 cells could lower serum and liver blood lipid levels, alleviate liver damage and improve glucose tolerance test (GTT) and insulin tolerance test (ITT) indexes. v/i/uH6 cells improved the gut microbial composition and significantly reduced the Firmicutes to Bacteroidetes ratio (F/B ratio) in feces. In particular, Muribaculaceae may be a potential biomarker for effective cholesterol reduction. Also, the recovery of these biochemical indices and gut microbiome was found following fecal microbiota transplantation (FMT) using stool from vH6 treated mice. The v/i/uH6 cells increased the intestinal flora metabolism of vitamins-cofactors, as well as amino acids, while decreasing the relative content of primary bile acids. The Pearson correlation analysis showed that norank_f__Muribaculaceae and Lactobacillus had a negative correlation with blood lipid levels. Overall, v/i/uH6 cells were effective in improving hypercholesterolemia in mice, and this effect was attributed partly to the regulation of intestinal microbiota and metabolites related to lipid metabolism. Our findings provided a theoretical basis for the industrial development of probiotics and postbiotics and the treatment of cholesterol diseases.

Hypercholesterolemia is the leading cause of cardiovascular disease worldwide. In this study, the lactic acid bacteria (Lactobacillus plantarum H6) screened from homemade fermented foods in northeastern China were used to study their cholesterol-lowering ability and to analyze their degradation mechanism. Results showed that L. plantarum H6 significantly reduced serum cholesterol levels in C57BL/6 mice fed a hypercholesterolemia diet. It mainly promoted the expression of CYP7A1 gene by inhibiting the farnesoid X receptor pathway to increase the in vivo synthesis of bile acids and improved the intestinal microbial community structure of C57BL/6 mice to increase the abundance of bacterial flora containing bile salt hydrolase activity. Hence, L. plantarum H6 played a role in reducing the cholesterol content in mice.

We co-cultured Caco-2 cells with Lactobacillus salivarius and L. plantarum in vitro to investigate their immunoregulatory mechanisms and detected Lactobacillus strains adhering to Caco-2 cells expressing mRNAs of cytokines and Toll-like receptors (TLRs) by fluorescent quantitative reverse transcription–polymerase chain reaction. The strains were intragastrically administered to mice. Thymus/spleen indexes were measured on different days. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, flow cytometry, and enzyme-linked immunosorbent assay were performed to assess different variables. Results showed increased mRNA expressions of T helper 1 (Th1), various cytokines, surface receptors, TLRs (2, 4, and 9), thymus/spleen indexes, spleen lymphocyte transformation rate, macrophage energy metabolism and phagocytosis, CD11c⁺CD80⁺ cell number, interferon-γ secretion, and sIgA secretion levels; inhibition of nuclear factor-κB inflammation signal pathway; and downregulated mRNA expression of specific interleukins. Both Lactobacillus strains can promote naive T cell differentiation (Th1) and participate in immunomodulatory responses, featuring a potential in prevention and management approaches for foodborne diseases.