Akkermansia and its metabolites play key roles in the treatment of campylobacteriosis in mice

Effect of pectinase addition in juice processing on the structural characteristics, immunological activity and in vitro and in vivo prebiotic properties of apple pomace pectic polysaccharides

Apple pomace is a waste in fruit juice processing and is an important raw material for pectin extraction. The addition of pectinase will not only change the juice characteristics but also affect the apple pomace. However, the differences in the structure and function of pectin obtained from the pectinase-treated (TAPP) and untreated apple pomace (NTAPP) are unclear. In this paper, TAPP and NTAPP (APPs) were prepared using the subcritical-water method. Structural analysis showed that the APPs were acidic-pectin polysaccharides with low molecular weight (Mw) and a high esterification degree (DE), but TAPP had a lower Mw, DE, and galacturonic acid content and smoother surface. Immune activity detection demonstrated that NTAPP can stimulate macrophage proliferation, phagocytosis, and cytokine release by activating the TLR4/p-ERK/p-NFκB pathway, while TAPP activates the TLR4/p-NFκB to stimulate macrophage phagocytosis and the cytokine release. In vitro fermentation characteristics indicate that anaerobic fermentation using APPs as the sole carbon source can significantly promote the production of lactic acid and the short-chain fatty acids (SCFAs). Microbial diversity analysis revealed that the APPs exhibit prebiotic properties, but their effects on the gut microbiota composition differ: TAPP mainly promotes the enrichment of Akkermansia, while NTAPP primarily enhances the abundance of Faecalibaculum and Dubosiella. Finally, structure-function correlation analysis suggests that monosaccharide composition (particularly mannose) and molecular weight (Mw) are key factors influencing the gut microbiota composition, providing a research direction for future studies on their structure-activity relationships.

The role of Akkermansia muciniphila in maintaining health: a bibliometric study

Background

Akkermansia muciniphila, as a probiotic, is negatively linked to IBD, obesity, and T2DM. The aim of this study was to comprehensively assess the research status of Akkermansia muciniphila over the past decade and explore the relationships between this bacterium and various health-related aspects.

Methods

Tools VOSviewer, Bibliometrix, and CiteSpace were used to analyze various aspects including publication metrics, contributors, institutions, geography, journals, funding, and keywords.

Results

Over the past decade, research on Akkermansia muciniphila has demonstrated a consistent annual growth in the number of publications, with a notable peak in 2021. China led in the number of publications, totaling 151, whereas the United States exhibited a higher centrality value. Among the 820 institutions involved in the research, the University of California (from the United States) and the Chinese Academy of Sciences (from China) occupied central positions. Willem M. De Vos ranked at the top, with 12 publications and 1,108 citations. The journal GUT, which had 5,125 citations and an Impact Factor of 23.0 in 2024, was the most highly cited. The most cited articles deepened the understanding of the bacterium's impact on human health, spanning from basic research to translational medicine. Thirty-nine high-frequency keywords were grouped into five clusters, illustrating Akkermansia muciniphila's associations with metabolic diseases, chronic kidney disease, the gut-brain axis, intestinal inflammation, and Bacteroidetes-Firmicutes shifts.

Conclusion

Given Akkermansia muciniphila's anti-inflammatory and gut-barrier-strengthening properties, it holds promise as a therapeutic for obesity, metabolic disorders, and inflammatory conditions. Therefore, future research should explore its potential further by conducting clinical trials, elucidating its mechanisms of action, and investigating its efficacy and safety in diverse patient populations.

Dietary bile acids supplementation protects against Salmonella Typhimurium infection via improving intestinal mucosal barrier and gut microbiota composition in broilers

BACKGROUND

Salmonella Typhimurium (S. Typhimurium) is a common pathogenic microorganism and poses a threat to the efficiency of poultry farms. As signaling molecules regulating the interaction between the host and gut microbiota, bile acids (BAs) play a protective role in maintaining gut homeostasis. However, the antibacterial effect of BAs on Salmonella infection in broilers has remained unexplored. Therefore, the aim of this study was to investigate the potential role of feeding BAs in protecting against S. Typhimurium infection in broilers.

METHODS

A total of 144 1-day-old Arbor Acres male broilers were randomly assigned to 4 groups, including non-challenged birds fed a basal diet (CON), S. Typhimurium-challenged birds (ST), S. Typhimurium-challenged birds treated with 0.15 g/kg antibiotic after infection (ST-ANT), and S. Typhimurium-challenged birds fed a basal diet supplemented with 350 mg/kg of BAs (ST-BA).

RESULTS

BAs supplementation ameliorated weight loss induced by S. Typhimurium infection and reduced the colonization of Salmonella in the liver and small intestine in broilers (P < 0.05). Compared to the ST group, broilers in ST-BA group had a higher ileal mucosal thickness and villus height, and BAs also ameliorated the increase of diamine oxidase (DAO) level in serum (P < 0.05). It was observed that the mucus layer thickness and the number of villous and cryptic goblet cells (GCs) were increased in the ST-BA group, consistent with the upregulation of MUC2 gene expression in the ileal mucosa (P < 0.05). Moreover, the mRNA expressions of Toll-like receptor 5 (TLR5), Toll-like receptor 4 (TLR4), and interleukin 1 beta (IL1b) were downregulated in the ileum by BAs treatment (P < 0.05). 16S rDNA sequencing analysis revealed that, compared to ST group, BAs ameliorated the decreases in Bacteroidota, Bacteroidaceae and Bacteroides abundances, which were negatively correlated with serum DAO activity, and the increases in Campylobacterota, Campylobacteraceae and Campylobacter abundances, which were negatively correlated with body weight but positively correlated with serum D-lactic acid (D-LA) levels (P < 0.05).

CONCLUSIONS

Dietary BAs supplementation strengthens the intestinal mucosal barrier and reverses dysbiosis of gut microbiota, which eventually relieves the damage to the intestinal barrier and weight loss induced by S. Typhimurium infection in broilers.

Sulfate-Reducing Bacteria Induce Pro-Inflammatory TNF-α and iNOS via PI3K/Akt Pathway in a TLR 2-Dependent Manner

Desulfovibrio, resident gut sulfate-reducing bacteria (SRB), are found to overgrow in diseases such as inflammatory bowel disease and Parkinson's disease. They activate a pro-inflammatory response, suggesting that Desulfovibrio may play a causal role in inflammation. Class I phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway regulates key events in the inflammatory response to infection. Dysfunctional PI3K/Akt signaling is linked to numerous diseases. Bacterial-induced PI3K/Akt pathway may be activated downstream of toll-like receptor (TLR) signaling. Here, we tested the hypothesis that Desulfovibrio vulgaris (DSV) may induce tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS) expression via PI3K/Akt in a TLR 2-dependent manner. RAW 264.7 macrophages were infected with DSV, and protein expression of p-Akt, p-p70S6K, p-NF-κB, p-IkB, TNF-α, and iNOS was measured. We found that DSV induced these proteins in a time-dependent manner. Heat-killed and live DSV, but not bacterial culture supernatant or a probiotic Lactobacillus plantarum, significantly caused PI3K/AKT/TNF/iNOS activation. LY294002, a PI3K/Akt signaling inhibitor, and TL2-C29, a TLR 2 antagonist, inhibited DSV-induced PI3K/AKT pathway. Thus, DSV induces pro-inflammatory TNF-α and iNOS via PI3K/Akt pathway in a TLR 2-dependent manner. Taken together, our study identifies a novel mechanism by which SRB such as Desulfovibrio may trigger inflammation in diseases associated with SRB overgrowth.

Blockade of PI3K/AKT signaling pathway by Astragaloside IV attenuates ulcerative colitis via improving the intestinal epithelial barrier

BACKGROUND

The specific pathogenesis of UC is still unclear, but it has been clear that defects in intestinal barrier function play an important role in it. There is a temporary lack of specific drugs for clinical treatment. Astragaloside IV (AS-IV) is one of the main active ingredients extracted from Astragalus root and is a common Chinese herbal medicine for the treatment of gastrointestinal diseases. This study aimed to determine whether AS-IV has therapeutic value for DSS or LPS-induced intestinal epithelial barrier dysfunction in vivo and in vitro and its potential molecular mechanisms.

METHODS

The intestinal tissues from UC patients and colitis mice were collected, intestinal inflammation was observed by colonoscopy, and mucosal barrier function was measured by immunofluorescence staining. PI3K/AKT signaling pathway activator YS-49 and inhibitor LY-29 were administered to colitic mice to uncover the effect of this pathway on gut mucosal barrier modulation. Then, network pharmacology was used to screen Astragaloside IV (AS-IV), a core active component of the traditional Chinese medicine Astragalus membranaceus. The potential of AS-IV for intestinal barrier function repairment and UC treatment through blockade of the PI3K/AKT pathway was further confirmed by histopathological staining, FITC-dextran, transmission electron microscopy, ELISA, immunofluorescence, qRT-PCR, and western blotting. Finally, 16 S rRNA sequencing was performed to uncover whether AS-IV can ameliorate UC by regulating gut microbiota homeostasis.

RESULTS

Mucosal barrier function was significantly damaged in UC patients and murine colitis, and the activated PI3K/AKT signaling pathway was extensively involved. Both in vivo and vitro showed that the AS-IV-treated group significantly relieved inflammation and improved intestinal epithelial permeability by inhibiting the activation of the PI3K/AKT signaling pathway. In addition, microbiome data found that gut microbiota participates in AS-IV-mediated intestinal barrier recovery as well.

CONCLUSIONS

Our study highlights that AS-IV exerts a protective effect on the integrality of the mucosal barrier in UC based on the PI3K/AKT pathway, and AS-IV may serve as a novel AKT inhibitor to provide a potential therapy for UC.

Promising probiotic-fermented soymilk for alleviating acute diarrhea: insights into the microbiome and metabolomics

Fermented soymilk (FSM4) has attracted much attention due to its nutritional and health characteristics. Exploring FSM4 products to alleviate diarrhea can ensure their effectiveness as a therapeutic food for alleviating gastrointestinal disorders. However, the relationship between gut microbiota and gut metabolite production remains unknown during diarrheal episodes. Therefore, the diarrhea-alleviating role and mechanisms of FSM4 in diarrhea rats were investigated via biochemical, gut microbiota, and serum metabolite analyses. The findings showed that consuming FSM4 improved diarrhea symptoms and reduced systemic inflammation better than non-fermented soymilk (NFSM). It is worth noting that FSM4 promoted the diversity, richness, structure, and composition of gut microbiota. It increased the ability to reduce inflammation associated with harmful bacteria (Anaerofilum, Flavonifractor, Bilophila, Anaerostipes, [Ruminococcus]_torques_group, Clostridium_sensu_stricto_1, Turicibacter, Ruminococcus_1, Ruminiclostridium_6, Prevotellaceae_NK3B31_group and Fusicatenibacter), while stimulating the growth of healthy species (Lactobacillus, Ruminococcaceae_UCG-014, Oscillibacter, [Eubacterium]_coprostanoligenes_group, Negativibacillus, and Erysipelotrichaceae_UCG-003). Moreover, metabolomics analysis showed that lipid metabolites such as lysophosphatidylethanolamine (LysoPE) and sphingolipids were upregulated in the NG group, closely related to pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, and IFN-γ) and the aforementioned pathogenic bacteria. Notably, in treatment groups, especially FSM4, the accumulation of L-ornithine, aspartic acid, ursocholic acid, 18-oxooleate, and cyclopentanethiol was increased, which was robustly associated with the anti-inflammatory factor IL-10 and beneficial bacteria mentioned above. Therefore, it can be inferred that the amino acids, bile acid, 18-oxooleate, and cyclopentanethiol produced in the FSM4 group can serve as metabolic biomarkers, which synergistically act with the gut microbiota to help alleviate inflammation for diarrhea remission. Overall, FSM4 may provide a new alternative, as an anti-inflammatory diet, to alleviate diarrhea.

Effects of Bacillus halophilus on growth, intestinal flora and metabolism of Larimichthys crocea

The incorporation of probiotics into the diet of large yellow croaker has been demonstrated by several studies to confer partial disease resistance. Bacillus halophilic isolated from the intestinal flora was used to study its effects on performance growth indicators, intestinal tissue structure, intestinal flora and the metabolism of Larimichthys crocea. A total of 180 fishes with an initial body weight of (164.00 ± 54.00) g were fed diets with three different concentrations of Bacillus halophilic: 0 cfu/mL (FC0, control group), 108 cfu/mL (FC8, treatment group), and 1012 cfu/mL (FC12, treatment group). The results showed that there were no significant differences in specific growth rate among all groups (P > 0.05). Compared to the FC0 group, the final body weight and Weight gain rate were significantly higher in FC8 and FC12 groups (P < 0.05). The Survival of the FC12 group significantly improved (P < 0.05). Compared to the FC0 group, crude protein content in muscle of the FC8 group significantly increased (P < 0.05), crude fat content significantly increased in the FC12 group (P < 0.05), crude protein content in whole fish experimental groups significantly increased (P < 0.05), and ash content significantly increased in the FC8 group (P < 0.05). In terms of antioxidant ability, the content of LZM in blood increased significantly in the FC8 group (P < 0.05), GSH content in liver of the FC12 group increased significantly (P < 0.05), while the content of MDA and AKP in blood and liver had no significant difference (P > 0.05). At the level of intestinal structure, there were no significant differences in villus height, crypt depth and goblet cell number between control group and treatment groups (P > 0.05). At the phylum level, Firmicutes was the dominant phylum, and the genus level, Lactobacillus and Bacteroides were the dominant bacteria in FC8 and FC12. A total of 1070 metabolites were identified, among which lipid metabolites accounted for 46.7%. Metabolites were involved in six main ways, mainly related to the metabolism of amino acids and lipids. The correlation analysis between microbes and metabolites showed that the intestinal flora of Larimichthys crocea could promote the synthesis of metabolites, among which Bacteroides and Megamonas could promote the synthesis of beneficial metabolites such as amino acids and vitamins. Through this study, we found that Bacillus halophilic can significantly improve growth, the antioxidant immunity ability and promote the expression of growth related metabolites, with the FC12 group being the better successful.

The Protective Effect of Heat-Inactivated Companilactobacillus crustorum on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Heat-inactivated microorganisms are a typical class of postbiotics with promising potential health effects, as they contain various physiologically active components. Dietary supplementation with Companilactobacillus crustorum MN047 (CC) has been shown to have the potential to alleviate ulcerative colitis (UC). However, it is unclear whether the UC-relieving effect of this strain is partly attributed to its bacterial composition. Therefore, the interventional effects of heat-inactivated CC (HICC) on UC mice were explored. The results showed that the administration of HICC significantly ameliorated the UC-related pathological parameters by (1) alleviating the pathologic lesions of UC (e.g., preventing the increase in disease activity index and the shortening of colon length); (2) ameliorating the colonic inflammation (e.g., inhibiting the expressions of chemokines and pro-inflammatory cytokines, such as Cxcl1, Cxcl5, Ccl7, TNF-α, IL-1β, IL-6, and MCP-1; (3) attenuating the oxidative damage (e.g., suppressing the increase in myeloperoxidase and malondialdehyde); (4) mitigating the damage of gut barrier (e.g., promoting colonic occludin, ZO-1, and claudin levels); and (5) modulating gut microbiota structure (e.g., increasing the relative abundance of potential probiotics, such as Akkermansia and Lactobacillus). In conclusion, our study suggested that HICC can be effective in preventing UC and has the potential as a dietary supplement to intervene in UC.