Gut Microbes最新文献

Hypercholesterolemia is a major risk factor for atherosclerotic cardiovascular disease; however, current therapeutic options such as statins are limited by issues including hepatotoxicity and patient intolerance. Probiotics and their metabolites show promise in modulating cholesterol metabolism through the gut‒liver axis, yet the specific commensal bacteria and molecular mechanisms underlying these effects remain poorly understood. In this study, we isolated and characterized EPS-D1, a novel exopolysaccharide (15.003 kDa) derived from Lactiplantibacillus plantarum H6, which is composed primarily of mannose (46.10%) and glucose (33.98%) and features a highly branched structure (branching degree of 29.5%). The administration of EPS-D1 significantly reduced the serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) by 40.31%, 37.55%, and 43.15%, respectively, in high-cholesterol diet (HCD) mice. Additionally, it improved hepatic steatosis and reduced markers of liver injury. Through 16S rRNA sequencing and fecal microbiota transplantation (FMT), we identified Muribaculum as the key commensal bacterium enriched by EPS-D1. Direct administration of Muribaculum (Muribaculum intestinale) replicated the cholesterol-lowering effects, decreasing ileal and fecal cholesterol levels by 74.79% and 53.16%, respectively. Mechanistically, both EPS-D1 and M. intestinale activated the enterohepatic FXR‒FGF15 axis, which resulted in the upregulation of hepatic cholesterol 7α-hydroxylase (CYP7A1) expression and the downregulation of ileal ASBT and NPC1L1, thereby promoting bile acid synthesis and inhibiting cholesterol absorption. Furthermore, M. intestinale increased intestinal short-chain fatty acids (SCFAs), particularly acetic acid and caproic acid, by 37.88% while also modulating the composition of the bile acid pool. These findings establish M. intestinale as a precise microbial target for cholesterol management and demonstrate that EPS-D1 from L. plantarum H6 enhances cholesterol metabolism through microbiota-mediated activation of the enterohepatic FXR‒FGF15 axis, providing a novel therapeutic strategy for managing hypercholesterolemia.

Mycobacterial lung diseases, including tuberculosis (TB) and nontuberculous mycobacterial pulmonary disease (NTM-PD), are increasingly recognized as disorders influenced not only by host immunity but also by microbiota. Emerging evidence identifies the gut-lung axis (GLA) as a key bidirectional communication network linking intestinal and pulmonary homeostasis. Mycobacterial infection itself induces airway and gut dysbiosis through immune and metabolic disturbances, which is further exacerbated by prolonged antibiotic therapy. Dysbiosis within either site reciprocally affects the other via GLA, leading to reduced microbial diversity, impaired epithelial integrity, and systemic inflammation. These alterations disrupt metabolite-mediated immunoregulation and attenuate IL-22-driven epithelial defense, thereby weakening bacterial clearance and promoting chronic inflammation. Distinct microbial features, such as the depletion of beneficial SCFA-producing taxa and enrichment of pro-inflammatory anaerobes, are observed in both TB and NTM-PD. Moreover, therapy-induced microbiome remodeling influences treatment response and disease relapse. Restoring microbial balance through probiotics, prebiotics, postbiotics, dietary modulation, or fecal microbiota transplantation offers a promising adjunctive strategy. This review integrates current evidence linking microbiome dysbiosis to mycobacterial pathogenesis and highlights microbiome-targeted interventions as an emerging therapeutic frontier in pulmonary mycobacterial diseases.

The mechanisms by which gut microbiota modulate host immune responses remain incompletely understood. Here, we screened Lactobacillus and Bifidobacterium strains isolated from healthy individuals to identify symbionts capable of suppressing gut inflammation. Among them, Bifidobacterium adolescentis (Bifi-94) induced IL-10 production in mononuclear cells in vitro. Oral administration of Bifi-94 to mice treated with dextran sulfate sodium attenuated weight loss and reduced colonic inflammation scores. In wild-type C57BL/6 mice, Bifi-94 increased IL-10 levels in colonic tissue homogenates without altering the frequency of regulatory T cells. Instead, CD19⁺CD11b⁺ regulatory B (Breg) cells emerged as the primary source of IL-10, with their numbers significantly increasing in the peritoneal cavity (PEC) after treatment. IL-10 secretion by PEC cells was robustly activated by live, heat-killed, and formalin-fixed Bifi-94. Bifi-94-derived peptidoglycan (PG) selectively stimulated IL-10 production in CD19⁺CD11b⁺ Breg cells, and multi-omics analyses showed that Bifi-94 exhibits increased expression of PG biosynthetic enzymes (MurE, MurD, Alr, UppP) relative to the type strain. Mechanistically, Bifi-94-derived PG promoted TLR2-dependent activation of ERK and p38 MAPK signaling in Breg cells. Notably, PG similarly enhanced IL-10 production in CD19⁺ B cells from human colonic tissue. These findings demonstrate that Bifi-94-derived PG promotes IL-10 production in Breg cells via TLR2-mediated signaling, thereby contributing to the attenuation of gut inflammation.

Responses to lung injury can vary between individuals with the diet and gut microbiome representing two underappreciated sources for this variability. The gut microbiome can influence lung injury outcomes through the gut‒lung axis, but exactly how diet and its effects on the microbiota are involved remains unclear. We hypothesized that dietary fiber interventions would favor the presence of short-chain fatty acid (SCFA)-producing fermentative bacteria presence in the gut microbiome, thereby influencing the resting lung immunometabolic tone as well as influencing downstream responses to lung injury and infection. To test this hypothesis, we fed mice fiber-rich (FR) and fiber-free (FF) diets, and observed changes in the steady-state transcriptional programming of alveolar macrophages (AM). Next, we examined the effects of the FR and FF diets on murine responses to sterile and infectious lung injury in vivo while simultaneously profiling the gut microbiota and SCFA levels transmitted along the gut‒lung axis. Finally, we validated our in vivo observations with mechanistic studies of the metabolic, signaling, and chromatin-modifying effects of specific SCFAs on lung AM ex vivo and in vitro. Overall, our fiber-rich diet reprogrammed AMs and attenuated lung inflammation after sterile injury while exacerbating lung infection. This effect of FR diets could be transferred to germ-free (GF) mice by fecal microbiome transplantation (FMT) and depended on the ability of the microbiota to produce propionate. Mechanistically, SCFAs altered the metabolic programming of AMs and lung tissue ex vivo without a clear role for free fatty acid receptors (FFAR) or chromatin remodeling. These findings demonstrate that the gut‒lung axis can regulate resting lung metabolic tone through dietary fiber intake and the enrichment of SCFA-producing gut bacteria, as well as influence sterile and non-sterile lung injury responses. These results provide evidence to support the development of therapeutic dietary interventions to preserve or enhance specific aspects of host pulmonary immunity.

Chronic intestinal pseudo-obstruction (CIPO) is characterized by bowel dilation and obstructive symptoms without any structural blockage. Although the microbiota is known to affect gastrointestinal function, its role in CIPO is poorly understood. We aimed to characterize the CIPO microbiota, investigate its role in disease expression and explore the therapeutic role of fecal microbiota transplantation (FMT). CIPO patients (n = 14) and healthy controls (HC, n = 12) were recruited from Italy and Canada. Microbiota profiles and functions were assessed by 16S rRNA sequencing and PICRUSt. Germ-free NIH Swiss mice were colonized with HC and CIPO microbiota, their intestinal transit and bowel distension were assessed by videofluoroscopy and computed tomography (CT), and the expression of host genes by NanoString®. The CIPO microbiota exhibited reduced microbial diversity with dominance of Proteobacteria and altered metabolic function. Mice with CIPO microbiota developed marked bowel distension and slow intestinal transit associated with altered expression of multiple genes related to immunity, the intestinal barrier and neuromuscular function. FMT from a HC improved the microbiota profile, intestinal transit and bowel distension in both CIPO mice and a selected CIPO patient, in whom a marked clinical improvement was sustained for 8 y. Thus, our findings support the use of microbiota-directed therapies to induce clinical improvement in CIPO patients.

Emerging evidence reveals a strong connection between the gut microbiota and cancer. However, the exact role of gut microbiota dysbiosis in multiple myeloma (MM) is poorly understood, and the therapeutic potential of microbiota-targeted interventions represents a promising strategy that demands urgent mechanistic and translational investigation. First, we conducted a comprehensive microbiome-metabolite analysis between MM patients and healthy individuals. The result revealed a marked compositional difference characterized by reduced abundances of butyrate-producing bacteria and diminished butyrate levels in the MM cohort. Subsequent fecal microbiota transplantation demonstrated that the gut microbiota critically modulates MM progression, with healthy donor-derived microbiota reducing the tumor burden and concomitantly elevating serum butyrate. Furthermore, through function-based culturomics screening, Clostridium butyricum (C. butyricum) was identified as a key butyrate-producing specialist. C. butyricum or its metabolite butyrate significantly reduced the systemic tumor burden in 5TGM1 mice. Notably, C. butyricum and butyrate alleviated bone marrow inflammation and osteolytic lesions by suppressing Th17 cells and IL-17 levels in the bone marrow. Moreover, cellular assays and transcriptome sequencing further revealed that butyrate could induce MM cells' apoptosis via HDAC inhibition-mediated upregulation of PPARγ, leading to sequential suppression of the PI3K/AKT pathway and antiapoptotic BCL-2 expression. This apoptotic signaling cascade was reversed by PPARγ antagonism. The direct antitumor effect was further confirmed in M-NSG mice. Our research systematically verifies the specific role of the gut microbiota in MM and provides the first evidence of the immune and molecular mechanisms by which C. butyricum alleviates MM progression, offering preclinical support for probiotic-based therapies against MM.

Objective: This study investigates whether live Akkermansia muciniphila Muc^T supplementation can counteract obesity and metabolic dysfunctions induced by a high-fat diet (HFD) by modulating intestinal mucus production, secretion and composition.

Design: C57BL/6J mice were fed an HFD with or without live A. muciniphila Muc^T (2 × 10⁸ CFU per day) supplementation or a control diet for 6 weeks. Body weight, fat mass gain and metabolic markers were measured. Intestinal mucus characteristics were assessed via gene expression analysis of mucins and analysed mucin glycosylation by tandem mass spectrometry (MS/MS).

Results: Mice receiving live A. muciniphila Muc^T exhibited reduced body weight gain and fat mass accumulation compared to HFD controls, without changes in muscle mass. A. muciniphila improved gut barrier integrity by increasing antimicrobial peptide expression in the jejunum and in the colon of HFD-fed mice. Furthermore, live A. muciniphila Muc^T influenced markers of goblet cell differentiation and restored the expression of mucin markers altered by HFD. Specifically, live A. muciniphila Muc^T counteracted HFD-induced mucin 3 (Muc3) expression depletion in the colon. Although the overall mucus thickness was not affected by live A. muciniphila Muc^T, the bacteria significantly modulated mucin glycans composition. Live A. muciniphila Muc^T did not change the gut microbiota composition.

Conclusion: These findings highlight the protective effects of live A. muciniphila Muc^T against diet-induced metabolic dysfunctions by modulating adiposity, mucus layer composition, and glycan profiles. This reinforces its potential as a therapeutic strategy for metabolic disorders associated with gut microbiota alterations.

Emerging evidence underscores bidirectional communication along the microbiota-gut-brain axis in neuropsychiatric disorders. However, the field lacks dedicated metagenomic resources with standardized phenotyping for these conditions. Existing single-cohort studies face inherent limitations due to restricted sample sizes, confounding heterogeneity, and methodological fragmentation, compromising reproducibility and mechanistic insights. To overcome these challenges, we constructed the Gut Microbiome in Multinational Integrated Neuropsychiatric Disorders (GutMIND) database, a comprehensive resource integrating shotgun metagenomic data with harmonized metadata. Adhering to a standardized preprocessing protocol and rigorous quality control workflow, this dataset represents the largest gut-brain microbiome repository to date, encompassing 31 studies across 12 countries (n = 3,492) spanning 14 neuropsychiatric conditions. Utilizing this dataset, we characterized microbial community heterogeneity, which was significantly elevated in patients compared to healthy controls. Subsequently, we developed a computational framework, MetaClassifier, enabling the diagnosis of neuropsychiatric disorders and the identification of microbial biomarkers. Employing a comprehensive two-stage validation strategy, we first assessed the model utilizing taxonomic abundance profiles via nested cross-validation in the high-quality discovery cohort (n = 2,734), achieving a mean AUROC of 0.69 (range: 0.55-0.78) across 8 disorders. Its robustness was further confirmed in an independent platform-extended validation cohort (n = 400), yielding a mean AUROC of 0.71 (range: 0.60-0.76). We also developed the Microbial Gut-Brain Axis Health Index (MGBA-HI), which effectively distinguished neuropsychiatric status in both the high-quality cohort and the platform-extended cohort. Furthermore, integrative analysis of health-abundant species, index-derived biomarkers, and ecological prevalence, we identified 9 core neuropsychiatric-protective microbiota. These species predominantly exhibited metabolic capacities linked to glutamate synthesis and acetate production. Building upon this, the GutMIND framework ensures robust cross-cohort comparability while minimizing technical heterogeneity, thereby enhancing inferential rigor in gut microbiome-neuropsychiatry research. Notably, the MetaClassifier, MGBA-HI, and core microbiota hold translational potential for developing microbiome-based prognostic tools and personalized therapeutic strategies in neuropsychiatric disorders. The source code and usage instructions for MetaClassifier are accessible at https://github.com/juyanmei/MetaClassifier.

Intestinal immune homeostasis is crucial for intestinal function and health. Increasing evidence suggests that certain gut microbiota can enhance the host's intestinal immune regulatory capacity. However, the mechanisms by which the microbiota confers beneficial traits and robust immunity to the host, as well as the cross-species reproducibility of these effects, remain unclear. This study, through multi-omics integration comparison and functional validation, revealed that Streptococcus hyointestinalis from Min pigs regulates macrophage polarization homeostasis by targeting and inhibiting the excessive activation of the STING signaling pathway and its downstream pro-inflammatory cascade reactions through its extracellular vesicles (EVs), thereby shifting them toward the M2 phenotype. This process ensures the integrity of the intestinal barrier and alleviates colitis induced by the combined effects of low temperature and sodium sulfate-induced colitis (DSS). Notably, in Sting^-/- mice, the EV-mediated intestinal protective effect was eliminated, confirming its targeted efficacy. Our data reveal a microbial EV‒STING‒macrophage axis in which symbiotic bacterial exosomes promote reparative macrophage programs by regulating STING signaling and maintaining intestinal integrity under environmental stress. These findings reveal a novel host-microbiota communication pathway with therapeutic potential for the treatment of inflammation-driven intestinal diseases.