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PubMed2026

Genome-Resolved Functional Profiling of Osteoporosis-Associated Gut Bacteria Highlights Putative Metabolic and Immunogenic Signatures of the Gut-Bone Axis.

The gut microbiota has emerged as a potential regulator of bone metabolism, but the genome-encoded functional repertoire of osteoporosis-associated gut bacteria remains insufficiently characterized. This study performed in silico functional profiling of gut bacterial taxa associated with osteoporosis, low bone mineral density, or comparator bone-related phenotypes. Twenty candidate taxa were selected from evidence in the human microbiome and represented by 26 curated bacterial reference genomes. Genome-wide annotations were used to map predicted gut-bone axis signatures, carbohydrate-active enzyme (CAZyme) repertoires, selected Kyoto Encyclopedia of Genes and Genomes pathways, and gutSMASH-predicted metabolic gene clusters. Functional burdens were normalized as hits per 1000 annotated proteins and integrated into metabolic, immunogenic, CAZyme, KEGG, and metabolic gene cluster profiles. Twelve predicted gut-bone axis signatures were identified, comprising 3337 primary candidate protein hits and a strict high-confidence subset of 2497 hits. Dominant signatures included vitamin B12/cobalamin metabolism, folate/one-carbon metabolism, peptidoglycan/cell-wall biosynthesis, and short-chain fatty acid-related functions. Dialister invisus, Dialister succinatiphilus, Megamonas funiformis, and Megamonas hypermegale showed the strongest normalized predicted gut-bone axis signal. These hypothesis-generating findings prioritize microbial metabolic and immunogenic features for future metagenomic, metabolomic, and experimental validation studies.

Osteoporosis↗

PubMed2026

Human DNA levels in feces reflect gut inflammation and associate with presence of gut species in IBD patients across the age spectrum.

BACKGROUND: Feces represent a complex biological matrix that provides valuable information about intestinal physiology and gut microbial activity. Comprehensive fecal DNA sequencing is mostly utilized as a non-invasive way to profile the gut microbiome, and both clinical practice and research on inflammatory bowel diseases (IBD) would greatly benefit from accurate and non-invasive methods to monitor gut inflammation in IBD patients. In IBD, excessive immune cell recruitment and epithelial cell shedding in the gut increase the amount of human DNA in feces, making fecal DNA profiling a desirable approach to monitor gut inflammation dynamics. METHODS: We used a combination of sequencing techniques to comprehensively characterize the fecal DNA diversity in a newly established cohort of pediatric IBD patients and controls (Pediatric cohort, N = 134 children, Israel). We performed methylation-based human cell-specific profiling together with shotgun metagenomics to characterize the human and the microbial DNA content in feces, respectively. Moreover, we included a large complementary external cohort including adult IBD patients and controls (Adult cohort, N = 689 adults, the Netherlands), not only to compare microbial patterns across the age spectrum, but also to extend our findings from the methylation-based profiling to the more broadly-available quantification of human DNA in metagenomic sequencing. RESULTS: We found that neutrophil DNA dominates fecal human DNA content in IBD patients, and our measurements were highly correlated with fecal calprotectin levels. Combining neutrophil and other cell type DNA fractions in one metric was able to distinguish between remissive and active cases of IBD. Human reads percentage by metagenomics was well correlated with disease severity and species richness, which had distinct trends in CD and UC over time. We used a combination of species richness, human DNA percentage, and microbiome composition data to predict IBD and distinguish CD from UC in both adult and pediatric IBD cohorts. CONCLUSIONS: The comprehensive characterization of human and microbiome fecal DNA is a useful approach to track immune response level and investigate the interaction that the immune system has with gut microbiome richness and composition over time, enriching opportunities for better disease monitoring and thus better treatment of IBD patients. Video Abstract.

Humans↗

PubMed2026

Deciphering the Microbiome-Gut-Eye Axis: A Mendelian Randomization Analysis of the Causal Influence of Gut Microbiota on Myopia.

INTRODUCTION: The intricate relationship between the gut microbiome and myopia is increasingly recognized, underscoring the need to explore its causal dynamics. Despite emerging evidence, the influence of Gut Microbiota (GM) on ocular development remains underexplored. METHODS: This study utilized Mendelian Randomization (MR) to investigate the causal impact of GM on the development of myopia. Instrumental variables (IVs) were identified from Genome-Wide Association Studies (GWAS), focusing on genetic variants significantly associated with microbiome composition. A comprehensive array of MR techniques was applied to ensure a robust estimation of causal effects and to adjust for potential confounders and pleiotropy. RESULTS: The Inverse-Variance Weighted (IVW) method was used to identify significant associations between GM and myopia. Increased risk of myopia was linked to the class Betaproteobacteria (OR=1.01, 95% CI 1.004-1.017, P=0.003), the order Burkholderiales (OR=1.009, 95% CI 1.001-1.016, P=0.02), the family Oxalobacteraceae (OR=1.005, 95% CI 1.001-1.01, P=0.023), and several genera including Eubacterium xylanophilum group (OR=1.007, 95% CI 1.001-1.013, P=0.033), and Bifidobacterium (OR=1.005, 95% CI 1-1.01, P=0.038). Protective effects were noted for the order Mollicutes RF9 (OR=0.994, 95% CI 0.99-0.999, P=0.014), the genus Allisonella (OR=0.996, 95% CI 0.993-0.999, P=0.019), the genus Lachnospiraceae UCG001 (OR=0.994, 95% CI 0.989-1, P=0.045), and the family Enterobacteraceae (OR=0.991, 95% CI 0.982-1, P=0.047) and order Enterobacteriales (OR=0.991, 95% CI 0.982-1, P=0.047). Sensitivity analyses further confirmed the robustness of these findings. DISCUSSION: This study provides causal evidence for the "Microbiome-Gut-Eye Axis" in myopia development, identifying specific gut microbiota that influence myopia risk. These findings suggest potential for microbiota-targeted interventions, warranting further research in diverse populations. CONCLUSIONS: The findings support the "Microbiome-Gut-Eye Axis" as a potential factor in myopia pathogenesis and highlight microbiota-targeted interventions as novel therapeutic strategies for managing myopia. This study lays the groundwork for further research on how modifying GM can influence eye health and offers new perspectives on preventive health strategies.

Humans↗

PubMed2025

The Aggregated Gut Viral Catalogue (AVrC): A unified resource for exploring the viral diversity of the human gut.

The growing interest in the role of the gut virome in human health and disease, has led to several recent large-scale viral catalogue projects mining human gut metagenomes each using varied computational tools and quality control criteria. Importantly, there has been to date no consistent comparison of these catalogues' quality, diversity, and overlap. In this project, we therefore systematically surveyed nine previously published human gut viral catalogues. While these catalogues collectively screened >40,000 human fecal metagenomes, 82% of the recovered 345,613 viral sequences were unique to one catalogue, highlighting limited redundancy between the ressources and suggesting the need for an aggregated resource bringing these viral sequences together. We further expanded these viral catalogues by mining 7,867 infant gut metagenomes from 12 large-scale infant studies collected in 9 different countries. From these datasets, we constructed the Aggregated Gut Viral Catalogue (AVrC), a unified modular resource containing 1,018,941 dereplicated viral sequences (449,859 species-level vOTUs). Using computational inference tools, annotations were obtained for each vOTU representative sequence quality, viral taxonomy, predicted viral lifestyle, and putative host. This project aims to facilitate the reuse of previously published viral catalogues by the research community and follows a modular framework to enable future expansions as novel data becomes available.

Humans↗

PubMed2025

Gut Colonization With Vancomycin-Resistant Enterococcus Shapes the Gut Microbiome in the Intensive Care Unit.

BACKGROUND: Gut pathogen colonization with vancomycin-resistant Enterococcus (VRE) is common in the intensive care unit (ICU) and is associated with worse clinical outcomes; however, the timing of VRE colonization and its collateral effects on the gut microbiome are incompletely understood. METHODS: Medical ICU patients admitted with sepsis and receiving broad-spectrum antibiotics were sampled via deep rectal swabs at ICU admission and on ICU day 3, 7, 14, and 30. Rectal swabs were cultured for VRE on selective media and analyzed via 16S ribosomal RNA gene sequencing. RESULTS: Ninety patients were sampled (340 longitudinal swabs). VRE positivity rose from 20% at ICU admission to a peak of 33% by ICU day 14 and then modestly declined to 31% by ICU day 30. Paralleling this, alpha diversity fell while Enterococcus relative abundance rose through ICU day 14 with both returning to baseline by ICU day 30. The median relative abundance of Enterococcus was 38% (interquartile range [IQR], 7.4%-75%) for VRE-positive samples compared to 0.01% (IQR, 0%-19%) for VRE-negative samples (rank-sum P < .01); 38 samples had ≥90% Enterococcus and 8 samples were 100% Enterococcus by sequencing. VRE was associated with lower alpha diversity (median Shannon index 1.90 [IQR, 0.89-2.66] if VRE positive versus 2.64 [IQR, 1.58-3.22] if VRE negative; P < .01). CONCLUSIONS: VRE gut colonization peaked at ICU day 14 followed by a modest decline and was associated with low alpha diversity. Improved understanding of dynamic changes in the gut microbiome may facilitate successful future ICU interventions. CLINICAL TRIALS REGISTRATION: NCT03865706.

Aged↗

PubMed2026

The antimicrobial gut resistome of the Wayampi reveals a shared background of antibiotic and metal resistance genes with industrialized populations, underscoring the "robust-yet-fragile" architecture of human gut microbiomes.

BACKGROUND: Metagenomics enables detailed profiling of genes encoding antimicrobial resistance. However, most studies focus exclusively on antibiotic resistance genes (ARGs), excluding those associated with non-antibiotic antimicrobials (metals, biocides), and often rely on methods with low-sensitivity and low-specificity. Furthermore, they rarely examine populations exposed to minimal anthropogenic pollution. We analyzed fecal resistomes of 95 Wayampi individuals, an Indigenous community in remote French Guiana, using a targeted metagenomic capture platform covering 8667 genes, including ARGs, metal resistance genes (MRGs) and biocide resistance genes (BRGs) (PMID: 29335005). Resistome profiles were compared with those of Europeans to assess population-level differences. RESULTS: ARG richness was similar between groups (259 in Wayampi vs. 264 in Europeans, 159 shared), but MRGs + BRGs gene richness was significantly higher in Wayampi (11,930 vs. 7419). Most genes appeared in a minority of individuals (mean 5% for ARGs, 2% for MRGs + BRGs), but several ARGs for tetracyclines [tet(32), tet(40), tet(O), tet(Q), tet(W), tet(X), tetAB(P)], aminoglycosides (ant6'-I, aph3-III), macrolides (ermB, ermF, mefA), and sulfonamides (sul2) were present in all individuals. Tetracycline resistance genes predominated overall, while beta-lactam resistance genes were more common in Wayampi, and genes conferring resistance to aminoglycosides, amphenicols, and folate inhibitors were more frequent in Europeans. Among MRGs, copper and arsenic resistance genes prevailed in both groups, followed by those for zinc, iron, cobalt, and nickel. Up to 76% of Wayampiis carried acquired MRGs for copper (pcoABCDRS and tcrB), silver (silACFPRS), arsenic (ars), and mercury (mer) detoxification. Shannon diversity indices were similar for ARGs, MRGs, and BRGs, but composition and evenness differed significantly. UMAP and ADONIS analyses distinguished cohorts based on ARG profiles (p < 0.001), but not on MRGs or BRGs. Correlation analysis revealed conserved gene-sharing networks and introgression of acquired ARGs and MRGs within both gut microbiomes. CONCLUSIONS: The diverse and balanced Wayampi resistome reflects a less perturbed microbiome compared to industrialized populations, and reveals a background of "core" and "shell" acquired ARGs and MRGs, consistent with the "robust-yet-fragile" architecture of scale-free networks. The patchy yet resilient gene distribution suggests varying levels of conserved gene sharing highways among populations, likely shaped by long-term microbial-human evolution, and supports a broader view on acquired antimicrobial resistance. Video Abstract.

Humans↗

PubMed2026

Glial Connexin-43 Is a Pathogenic Mechanism Promoting Gut Inflammation in Postoperative Ileus Induced by Gut Surgical Manipulation With Potential Relevance to Humans.

BACKGROUND & AIMS: Abdominal surgery often precipitates postoperative ileus (POI), a frequent and severe gastrointestinal (GI) motility disorder, through mechanisms that involve intestinal inflammation. Emerging data show that enteric glia acquire a reactive phenotype that aggravates POI, but how glia exert this effect remains unclear. Enteric glia express connexin-43 hemichannels (gCx43), which are implicated in neurological and inflammatory disorders. Thus, we aimed to decipher contributions of glial connexin-43 (Cx43) in the pathophysiology of POI. METHODS: We induced POI in mice using in vivo intestinal manipulation and used glial Cx43cKO (Sox10CreERT2;Cx43fl/fl) or RiboTag (Sox10CreERT2/Rpl22HA/+) mice to evaluate Cx43-dependent signaling. Human enteric glial cultures (hEGC) and muscularis externa obtained during intestinal surgery translated findings to patients. Transcriptome analysis, immunofluorescence co-labeling, Western blots, and Cx43 hemichannel activation were used for quantitative analysis. RESULTS: Cx43 is the highest expressed connexin in enteric glia in mice and humans. Up-regulation of Cx43 occurs in various disease models linked to POI, GI surgical trauma, inflammation, immune cell activation, and enteric gliosis. In the mouse POI model, glial Cx43-deletion reduces glial reactivity, pro-inflammatory signals, upregulates host protection genes, regulates immune cell activation, and prevents enteric neuropathy. In hEGCs, interleukin (IL)-1β induction opens Cx43 and stimulates release of IL-6 and C-C motif ligand 2 (CCL2). The Cx43 peptide inhibitor, 43Gap26, inhibits glial Cx43 activation, reduces IL-6 release, and blocks upregulation of macrophage activation factors and immune cell regulation factors. Surgical intestinal trauma in patients upregulates Cx43 during inflammation and enteric gliosis in mouse POI. CONCLUSIONS: Glial Cx43 signaling promotes enteric gliosis, immune cell activation, inflammation, and enteric neuropathy in mice with potential translatability to humans after intestinal surgical trauma and mechanical stress in POI. Interventions that block glial Cx43 activation may be protective against POI development.

Animals↗

PubMed2026

Brucellar spondylitis is associated with disturbance in gut microbiota and histamine metabolism associated inflammation.

BACKGROUND: The pathogenesis of brucellar spondylitis (BLS) has traditionally been considered to be primarily limited to local osteoarticular lesions. With the proposal of the "gut-spine axis" concept, the role of intestinal microecological dysbiosis in inflammatory spinal diseases has attracted in an increase of attention. The overactivated inflammatory cytokine network not only mediates bone destruction and intervertebral disc damage, but also forms a bidirectional interaction with gut microbiota dysbiosis through the "gut-spine axis," collectively driving disease progression. However, the inflammatory mechanism by which gut microbiota participates in the pathological process of BLS remains largely unclear. METHODS: This study recruited 20 BLS patients and 20 healthy donors. Multi-omics analysis including metagenomics, untargeted metabolomics, and targeted short-chain fatty acids (SCFAs) analysis, were used to compare the structural differences in gut microbiota between the two groups and screen for signature differential bacterial species. Plasma levels of histamine and histidine decarboxylase were measured by ELISA to clarify the role of differential histidine metabolic pathway in the disease. Additionally, plasma levels of lipopolysaccharide (LPS) and inflammatory cytokines (IL-1β, IL-6, IL-10, IL-17A, TNF-α) were detected by ELISA. The correlation between gut microbiota and inflammatory indicators was further analyzed. RESULTS: Compared to the healthy control group, the α-diversity of the gut microbiota in BLS patients was significantly reduced, with the microbial community structure exhibiting increased homogeneity. Beta diversity analysis revealed significant differences, suggesting that disease progression is associated with an overall imbalance in the gut microbiota and the deterioration of its specific structural composition. At the phylum level, the abundances of Actinomycetota, unclassified_d_Viruses, and Fusobacteriota were significantly increased in the gut microbiota of BLS patients compared to the control group, while the abundances of Bacillota and Pseudomonadota were significantly decreased. Further analysis revealed that, compared to the control group, the generic abundance of Enterococcus was significantly increased, while the proportions of Blautia, Faecalibacterium, Ruminococcus, Agathobacter, Roseburia, Clostridium, Eubacterium, Alistipes and Anaerobutyricum were significantly decreased. At the species level, the abundances of Enterococcus sp and Enterococcus-faecium were increased, whereas Blautia sp, Ruminococcus sp, Faecalibacterium sp, Faecalibacterium prausnitzii, Agathobacter rectalis, Eubacterium sp, Agathobacter sp, and Roseburia sp were decreased. Furthermore, untargeted metabolomics revealed that metabolites were enriched in the histidine metabolic pathway, and the levels of SCFAs including butyrate, isobutyrate, valerate, and 4-methylvalerate in the intestinal contents were reduced in BLS. Functional KEGG profiling revealed that key KOs involved in butyrate synthesis (e.g., K00074, K00172, K01640) and transport were globally downregulated in the patient group, whereas histidine decarboxylase KOs (K01693, K11755, K19787) that convert histidine to pro-inflammatory histamine were significantly enriched. The loss of butyrate-producing symbionts led to SCFAs deficiency and mucosal barrier disruption, creating ecological niches for facultatively anaerobic Enterococcus, which further exacerbated local inflammation via proteolytic fermentation and histamine production. Compared with the control group, BLS patients showed decreased plasma levels of IL-10, while levels of IL-1β, IL-6, IL-17A, and TNF-α were increased, and LPS levels were elevated. In addition, significantly elevated plasma pro-inflammatory LPS levels in patients with BLS suggest disruption of intestinal integrity and permeability. Correlation analysis indicated a close relationship between gut microbiota and inflammation. CONCLUSION: BLS is associated with gut microbiota dysbiosis and alterations in microbial metabolites, which may be linked to inflammatory responses and histamine metabolism. The differential microbial taxa identified in this study could be developed into a stool-based non-invasive diagnostic panel to facilitate early differentiation of BLS from other spinal disorders. Furthermore, restoring gut microbial balance through probiotic supplementation or dietary modulation may represent a promising adjunctive strategy to enhance the efficacy of standard antibiotic therapy and reduce disease recurrence.

Humans↗

PubMed2026

Gut Dysbiosis in Selected Gynecological Diseases Associated with Female Infertility: A Scoping Review.

Background/Objectives: Female infertility represents a significant public health issue. Available evidence supports the hypothesis that the gut microbiota may play an essential role in women's reproductive health and may serve as a diagnostic or prognostic biomarker in specific gynecological disorders. A substantial part of current research concerns disturbed communication between the hypothalamic-pituitary-ovarian axis and the gut microbiota, providing the basis for analyzing this phenomenon as the gut-ovary axis or the gut-vagina-ovary axis. The primary aim of this scoping review was to map the available evidence on the relationship between gut microbiota composition and female infertility, with particular emphasis on polycystic ovary syndrome (PCOS, currently polyendocrine metabolic ovarian syndrome, PMOS) endometriosis, and uterine fibroids. Methods: The review was conducted in accordance with the PRISMA Extension for Scoping Reviews (PRISMA-ScR). PubMed, Scopus, and Google Scholar were searched using terms related to gut microbiota, female infertility, PCOS, endometriosis, and uterine leiomyomas. Peer-reviewed publications in English published between 2015 and 2025 were considered. The included studies were descriptively synthesized to identify recurring microbiota patterns and research gaps. Results: The reviewed evidence indicates that gut dysbiosis may be associated with selected gynecological disorders affecting fertility, including PCOS, endometriosis, and uterine fibroids. The gut microbiome may have potential value as a biomarker supporting diagnosis, treatment selection, and prognosis. Conclusions: The gut microbiome represents a promising but still insufficiently validated area in the management of gynecological diseases associated with female infertility. Further high-quality clinical studies are needed to verify the effectiveness of microbiome-based therapies and to develop evidence-based guidelines for managing infertility associated with gut dysbiosis.

dysbiosis↗

PubMed2025

Alterations of gut microbiome in chronic rhinosinusitis: insights from a mendelian randomization study.

OBJECTIVE: Gut microbiome dysbiosis is associated with various diseases. Causal association between Chronic Rhinosinusitis (CRS) and gut microbiome is yet unknown. This study aimed to investigate the potential causal relationship between CRS and gut microbiome dysbiosis. METHODS: We used Genome-Wide Association Study (GWAS) data from FinnGen database for CRS. The Dutch Microbiome Project study provided data on gut microbiota species. A total of 334,182 individuals were included. Two-sample bidirectional Mendelian Randomization (MR) analysis was used to investigate causal relationship between CRS and gut microbiome. The main methods of evaluation were Inverse Variance Weighting (IVW), weighted median, weighted mode, and MR-Egger regression. Sensitivity analyses were performed to assess heterogeneity and pleiotropy. RESULTS: Forward MR analysis indicated CRS is potentially linked to decreased risk of Haemophilus parainfluenzae (OR = 0.79, 95% CI 0.66‒0.94, p = 0.009) and increased risk of Bilophila's (OR = 1.14, 95% CI 1.02-1.27, p = 0.023) within the gut. Reduced risks in gut microbiota-related pathways like UDP-N-acetyl-d-glucosamine biosynthesis I (OR = 0.85, 95% CI 0.77‒0.94, p = 0.002) and increased risk in pathway NAD biosynthesis I from aspartate (OR = 1.14, 95% CI 1.03-1.27, p = 0.010) were also linked to CRS. Reverse MR analyses, we obtained no positive results (p > 0.05/412). CONCLUSION: This study reveals CRS exerts a causal impact on shifts within the composition of the gut microbiome and also links to the changes of gut microbiota-related metabolic pathways. The risk of changes in gut microbiota should be of greater concern in patients with CRS than in the general population. LEVEL OF EVIDENCE: Mendelian Randomized (MR) studies are second only to randomized controlled trials in terms of the level of evidence.

Humans↗

PubMed2025

Plasma metabolites mediate the causal relationship between gut microbiota and erectile dysfunction: insights from Mendelian randomization study.

BACKGROUND: While the relationship between gut microbiota and erectile dysfunction (ED) has been reported, the specific pathways involved remain unclear. AIM: This study aims to investigate the causal relationship between gut microbiota and ED, and to identify the potential role of plasma metabolites as mediators. METHODS: Utilizing aggregated genome-wide association study (GWAS) data, a comprehensive two-sample Mendelian randomization (MR) analysis was performed involving 196 gut microbiota taxa, 1400 plasma metabolites and ED. Causal relationships between gut microbiota, plasma metabolites and ED were explored. In addition, mediation analysis was applied to identify the pathway from gut microbiota to ED mediated by plasma metabolites. OUTCOMES: This study reveals that plasma metabolites act as mediators regulating the influence of gut microbiota on ED. RESULTS: MR analysis identified causal relationships between six gut microbial taxa and ED, with Butyrivibrio increasing the risk of ED, while Alistipes, Prevotella 9, Dialister, Marvinbryantia, and LachnospiraceaeUCG010 exhibited protective effects. Additionally, 45 plasma metabolites demonstrated causal associations with ED. Finally, mediation analysis revealed four mediation relationships. Sensitivity analysis indicated no heterogeneity or pleiotropy in this study. CLINICAL IMPLICATIONS: Modulating gut microbiota or targeting specific metabolites may offer new therapeutic approaches for ED, highlighting the potential for microbiome-based interventions. STRENGTHS AND LIMITATIONS: The MR approach and large-scale GWAS data provide robust causal evidence, but the findings are limited by their focus on European populations and lack of experimental validation. Further studies are needed to confirm these mechanisms in diverse cohorts and functional models. CONCLUSION: This study establishes a causal link between gut microbiota, plasma metabolites, and ED, identifying specific microbial taxa and metabolites as key contributors to ED risk. The mediating role of plasma metabolites highlights potential therapeutic strategies, such as probiotics or dietary interventions targeting harmful metabolites.

Mendelian randomization↗

PubMed2026

Toxoplasma gondii infection disrupts secondary bile acid transformation in feline gut microbiota.

UNLABELLED: Bile acid (BA) transformation relies on gut microbiota and is vulnerable to Toxoplasma gondii infection, yet feline microbial BA-transforming capacity upon toxoplasmosis remains unclear. Here, we constructed a catalog of 2,474 nonredundant feline gut microbial genomes and integrated serum metabolomic data to verify BA transformation alterations. The results revealed that the feline gut microbiome harbored widespread genetic potential for BA transformation but lacked a complete 7α-dehydroxylation pathway due to the absence of the key gene baiE. The BA transformation-related genomes (2,045 in total) were predominantly from the phyla Bacillota_A and Actinomycetota, among which only 37 encoded baiB, all belonging to Bacillota_A. The distribution of BA transformation-related genes varied across intestinal regions: genes encoding 7α-HSDH were primarily enriched in the small intestine, whereas genes encoding 3α-HSDH, baiCD, and baiH were more abundant in the large intestine. Additionally, the abundance of genes encoding BSH and 3α-HSDH increased significantly in the small intestine on day 3 post-infection, accompanied by increases in the phylum Bacillota_C and genera such as Blautia_A, Enterococcus_E, and Ligilactobacillus. Serum metabolomics revealed a significant increase in cholesterol levels post-infection, supporting the impact of T. gondii infection on intestinal BA transformation. These findings illustrated that the feline gut microbiota played an important role in BA transformation and that T. gondii infection disrupted the microbial potential for secondary BA transformation. This study provided new insights into gut microbiota-associated metabolic perturbations during feline toxoplasmosis. IMPORTANCE: Bile acid (BA) transformation plays a critical role in host metabolism and immune regulation. Although studies on BA transformation are increasing, the capacity for BA transformation within the feline gut microbiota and the impact of Toxoplasma gondii infection on this capacity remain unclear. To bridge this gap, we constructed a catalog of 2,474 nonredundant feline gut microbial genomes and integrated serum metabolomic data to verify BA transformation alterations. Our findings revealed that the feline gut microbiome lacked a complete 7α-dehydroxylation pathway, and the specific functions involved in BA transformation may differ between the small and large intestines. Furthermore, integrated metagenomic and serum metabolomic analyses suggested that T. gondii infection disrupted BA transformation capacity in the small intestine. This study provided new insights into gut microbiota-associated metabolic perturbations during feline toxoplasmosis.

Toxoplasma gondii↗

PubMed2025

Effects of Sodium-Glucose Cotransporter-2 Inhibitors on Modulating Protein-Bound Uremic Toxins and Gut Microbiota in Predialysis CKD Patients: Matched Case-Control Study.

KEY POINTS: A reduction of indoxyl sulfate, p-cresyl sulfate, and several short-chain fatty acids was seen in sodium-glucose cotransporter-2 inhibitor-treated CKD patients. Variations in gut microbiota composition are correlated with levels of gut-derived uremic toxins in sodium-glucose cotransporter-2 inhibitor-treated CKD patients. BACKGROUND: The intricate interplay between CKD and intestinal microbiota has gained increasing attention, with gut dysbiosis being implicated in uremic toxin accumulation and CKD progression. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are now transforming CKD management but pose uncertain effects on shaping gut microbiota. This study aimed to elucidate the effect of SGLT2i on perturbations of gut microbial composition and metabolic responses in patients with CKD. METHODS: Analysis of fecal microbiota and targeted profiling of serum short-chain fatty acids and gut-derived uremic toxins were conducted in a matched case-control study, including 60 patients with CKD (treated: n=30; untreated: n=30) and 30 non-CKD controls. RESULTS: Gut microbial composition differed significantly among the three study groups. Patients with CKD receiving SGLT2i exhibited distinctive taxonomic profiles, such as enrichment of Bacteroides stercoris and Bacteroides coprocola. Surveys of metabolomic profiles revealed a reduction of two uremic solutes, indoxyl sulfate and p-cresyl sulfate (pCS), and several short-chain fatty acids (formic, acetic, propionic, valeric, and 2-methylbutanoic acid) in SGLT2i-treated CKD patients. Co-occurrence analysis demonstrated a set of intestinal microbes that is positively or negatively correlated with the levels of pCS, and the abundance of these pCS-associated intestinal microorganisms was correlated with the levels of indoxyl sulfate and isovaleric acids in the same and opposite direction, respectively. Further functional prediction indicated attenuated pathways related to protein and carbohydrate metabolism. CONCLUSIONS: Treatment with SGLT2i in patients with CKD is associated with distinct gut microbial composition and metabolite profiles, suggesting potential modulation of gut dysbiosis and metabolic pathways. Further studies are warranted to elucidate the clinical implications of these findings in CKD management.

CKD↗

PubMed2026

Two-sample Mendelian randomization study of gut microbiota and inflammatory proteins: Predictive, preventive, and personalized treatment for migraine.

The human gut microbiota is increasingly recognized as a significant factor in the pathogenesis of migraine, potentially via inflammatory pathways. Identifying specific human gut microbiota components associated with migraines, along with the investigation of particular inflammatory proteins, is essential for advancing primary prediction, targeted prevention, and personalized treatment strategies for migraines. We conducted a two-sample Mendelian randomization study using publicly available summary statistics from genome-wide association studies. Data for 473 human gut microbiota taxa were obtained from the Finnish national health survey conducted by the National Institute for Health and Welfare study (FINRISK, n = 5959 European participants). Genome-wide association study data (https://www.ebi.ac.uk/gwas/) for 91 circulating inflammatory proteins were obtained from 14,824 participants across 11 cohorts using the Olink Target 96 Inflammation panel. Migraine outcome data were obtained from the FinnGen R12 release, with cases defined using ICD-10 code G43. All genome-wide association study analyses were adjusted for sex, age, genotyping batch, and 10 genetic principal components to control population stratification (genomic inflation factors: 1.00–1.05). Inverse variance-weighted Mendelian randomization was the primary analysis method, with Mendelian randomization-Egger, weighted median, and mode-based methods as sensitivity analyses. Two-step Mendelian randomization mediation analysis quantified the proportion of the effects of human gut microbiota on migraine that are mediated through inflammatory proteins. Thirty-seven bacterial genera were found to be associated with migraine using the inverse variance-weighted method. Of these, 18 genera exhibited a negative association, while 19 genera demonstrated a positive association with migraine risk. Additionally, eight inflammatory proteins were found to increase the risk of migraine. Among human gut microbiota, four were observed to reduce inflammatory protein levels, whereas another four were associated with increased inflammatory protein levels. Additionally, five gut microbiota were identified to influence migraine through inflammatory proteins in both Mendelian randomization analyses. Specifically, Actinobacteria, Brachyspiraceae, CAG-269 sp001915995, and Paraglaciecola were found to affect migraine outcomes via inflammatory proteins, with mediation proportions of 12%, 19%, 15.5%, and 6.7%, respectively. Lawsonibacter sp002161175 was identified to influence migraine risk through Oncostatin-M and SLAM, with mediation proportions of 15.6% and 11.3%, respectively. Our study elucidated the role of specific human gut microbiota alterations in the pathogenesis of migraine and highlighted the mediating effects of inflammatory proteins. Targeting these particular human gut microbiota alterations offers a promising strategy for predictive, preventive, and personalized medicine in migraine management, resulting in substantial clinical advancements.

causality↗

PubMed2025

Effects of Different Feeding Patterns on the Gut Virome of 6-Month-Old Infants.

The gut microbiome is essential for infant health, and in recent years, the impact of enteroviruses on infant health and disease has received increasing attention. The transmission of breast milk phages to the infant gastrointestinal tract contributes to the shaping of the infant gut virome, while breastfeeding regulates the colonization of the infant gut virome. In this study, we collected fecal samples from healthy infants and analyzed the distribution characteristics of infant viral communities by viral metagenomic analysis, and analyzed the differences in infant viral communities under different feeding practices. Our results indicate that the infant intestinal virome consists of phages and eukaryotic viruses. Caudovirales and Microviridae dominated the phage composition, and except for Siphoviridae, which was more predominant in the intestines of formula-fed infants, there were no significant differences in the overall abundance of other Caudovirales and Microviridae in the intestines of infants with different feeding patterns. Breastfeeding can lead to a higher diversity of infant gut viruses through vertical transmission, and a highly diverse gut virome helps maintain the maturation of the gut microbiome. This study informs the shaping of gut virome in healthy infants by breastfeeding and contributes to further research on infant gut virome characteristics and formation processes.

Humans↗

PubMed2025

New evidence for the protective effect of gut microbiota regulation of ferroptosis-related proteins against osteoporosis.

Osteoporosis (OP), characterized by bone degradation and increased fracture susceptibility, constitutes a significant global health burden. Recent findings implicate gut microbiota and ferroptosis in the regulation of bone metabolism; however, causal evidence for the gut microbiota's influence on OP specifically via ferroptosis regulation remains to be established. This study employed two-sample Mendelian randomization (MR) using genome-wide association study (GWAS) summary statistics to investigate these causal relationships and delineate mediating pathways.We assessed causal links between gut microbiota, ferroptosis-related proteins, and OP risk. Associations for gut microbiota abundance and ferroptosis-related proteins were derived from GWAS data and Icelandic blood-derived protein quantitative trait loci, respectively. Outcome data for OP were obtained from the FinnGen Release R12. The primary analysis utilized the inverse variance weighted (IVW) method, supplemented by sensitivity analyses to evaluate heterogeneity and horizontal pleiotropy.  MR analysis identified 33 gut microbial taxa causally associated with OP risk: 13 protective and 20 detrimental. Similarly, 34 ferroptosis-related proteins were categorized as protective (18) or detrimental (16) for OP. Mediation analysis revealed that the protective effect of Terrisporobacter othiniensis on OP is partially mediated by the ferroptosis regulator MDM4 (indirect effect β = -0.020, 95% CI: -0.068 to 0.029), accounting for 6.8% of the total effect. Sensitivity analyses showed no significant evidence of heterogeneity or horizontal pleiotropy. This study provides the first genetically validated evidence supporting a causal relationship between specific gut microbiota, ferroptosis-associated proteins, and OP susceptibility. Specifically, Terrisporobacter othiniensis demonstrates a novel protective mechanism, modulating OP risk partly through the ferroptosis regulator MDM4. These findings broaden understanding of the "gut-bone axis" and highlight the gut microbiota-ferroptosis pathway, particularly the MDM4/p53 axis, as a promising target for novel OP prevention and therapeutic strategies.

Ferroptosis↗

PubMed2025

Immune-mediated indirect interaction between gut microbiota and bacterial pathogens.

BACKGROUND: In many animals, survival during infection depends on the ability to coordinate interactions between the host immune system and gut microbiota. These tripartite interactions, in turn, potentially shape pathogen virulence evolution. A key regulator of the immune system and, hence, bipartite interactions in insects is the immune deficiency (Imd) pathway, which modulates gut microbiota and pathogens by synthesizing antimicrobial peptides (AMPs) through the NF-κB transcription factor Relish. However, whether Imd-dependent AMPs mediate indirect interactions between gut microbiota and pathogens in a tripartite context remains unclear. Using RNAi-mediated knockdown of Tenebrio molitor Relish (TmRelish), we hypothesized that Imd-dependent AMPs influence indirect interaction between Providencia burhodogranariea_B (P. b_B) infection and the gut microbiota. RESULTS: TmRelish knockdown altered bipartite interactions by disrupting gut microbiota load and composition, increasing pathogen load, and ultimately leading to higher host mortality during infection. However, we did not find support for our tripartite hypothesis that Imd-dependent AMPs mediate indirect interactions between the gut microbiota and P. b_B infection, suggesting the involvement of alternative regulatory pathways or Imd-independent mechanisms. Nevertheless, our investigations of tripartite interactions showed a positive effect of P. b_B infection on gut microbiota load, which in turn stimulated the expression of a subset of AMPs. However, this upregulation of AMPs did not result in reduced P. b_B load. Notably, the gut microbiota did not affect pathogen load but promoted host survival during P. b_B infection, indicating a role in increasing host tolerance rather than resistance. CONCLUSIONS: These findings suggest that while Imd-dependent AMPs may not mediate tripartite interactions in our system, microbiota-host interactions, such as microbiota-mediated immune priming and changes in microbiota load, can shape infection outcomes. These effects on infection outcomes almost certainly exert important selective pressures on the evolution of bacterial virulence.

Animals↗

PubMed2026

The Mediating Role of Immune Cells in the Genetically Predicted Relationship between Gut Microbiota and Puerperal Sepsis: A Mendelian Randomization Study.

INTRODUCTION: The causal relationship between gut microbiota and puerperal sepsis (PS) remains unclear, and there is a lack of in-depth research regarding the potential mediating role of immune cells in this context. OBJECTIVE: This study aims to investigate the causal relationship between gut microbiota and PS using Mendelian randomization (MR) analysis and to assess the mediating effects of immune cells on the risk of PS onset through mediation analysis. MATERIALS AND METHODS: We selected data from large-scale genome-wide association studies (GWAS) involving 473 gut microbiota species, 731 immune cell phenotypes, and PS datasets. Univariate MR (UVMR) analysis was employed to explore the causal relationship between gut microbiota and PS, with the primary statistical method being inverse variance weighting (IVW). Multiple statistical models were applied for sensitivity analysis to minimize the confounding effects of horizontal pleiotropy and heterogeneity. Subsequently, a two-step mediation MR analysis was conducted to evaluate whether immune cells mediate the relationship between gut microbiota and PS. RESULTS AND DISCUSSION: Analysis using various statistical models indicated that 11 gut microbiota species (e.g., Azorhizobium, Bacillus velezensis, CAG-245 sp000435175, Lentimicrobiaceae, and Providencia) exhibited a causal relationship with PS. Further reverse causal analysis between PS and gut microbiota ruled out the possibility of reverse causality. The two-step mediation MR analysis demonstrated that the percentage of IgD-CD27- B cells (10.26%) and CD62L- monocytes (17.29%) partially mediated the effect of CAG-245 sp000435175 on PS risk. CONCLUSION: This study provides evidence of a causal relationship between the abundance of certain gut microbiota species and PS, while also revealing a potential mediating role of immune cells. These findings offer valuable theoretical insights into personalized treatment strategies and the development of novel diagnostic biomarkers for PS.

Humans↗