Biology subjects

Hoedt, E. C.

Publications and source records attributed to Hoedt, E. C..

4 recordsLinked to original sources

bioRxiv2025

Microbiota Modulation Induces Elevated Duodenal Eosinophils Upon Gluten Exposure in Mice: Implications for Non-Coeliac Gluten Sensitivity

A growing proportion of the non-celiac population experience adverse symptoms to gluten. The pathogenesis of non-coeliac gluten sensitivity (NCGS) is unclear, but elevated duodenal eosinophils and altered mucosa-associated microbiota (MAM) populations have been reported. Given the microbiomes role in gluten digestion and its susceptibility to antibiotics, we hypothesised that altering the microbiome with antibiotics would modify immune responses to gluten in mice. BALB/C mice consuming gluten-free chow received amoxicillin/clavulanate (5mg/kg) or PBS-vehicle daily for 5 days. Mice were then treated with a 3mg wheat-gluten suspension, or vehicle, on days 4 and 5 before sacrifice on day 7. Duodenal immune cells were analysed by histology and flow cytometry, while the duodenal MAM and faecal microbiome were characterised via 16S rRNA and shotgun metagenomic sequencing, respectively. Antibiotic treatment followed by gluten reintroduction significantly reduced Staphylococcus in the duodenal MAM, enriched Bacteroides in faeces, and resulted in altered microbial carbohydrate and lipid metabolism, compared to vehicle controls. Treatment with antibiotics and gluten also increased duodenal eosinophils which positively correlated with the genus Blautia. Flow cytometry revealed that antibiotics and gluten treatment resulted in a greater proportion of active eosinophils and epithelial {gamma}{delta} T-cells, compared to vehicle control mice. This study demonstrated that modulating the microbiome with antibiotics was sufficient to alter the immune response to gluten in mice. These findings suggest that the microbiome may determine the capacity for gluten to induce an immune response and offers a valuable insight into potential mechanisms underlying NCGS. New & NoteworthyA mouse model examined how microbial modulation affects immune responses to gluten. Antibiotic treatment followed by gluten reintroduction reduced duodenal Staphylococcus and altered microbial carbohydrate and lipid metabolism pathways in the faecal microbiome. Antibiotics and gluten treatment resulted in increased abundance and activation of duodenal eosinophils, and elevated {gamma}{delta} T-cells in the duodenal epithelium. These findings highlight the role the microbiome plays in gluten-induced immune responses, providing insights into mechanisms behind non-coeliac gluten sensitivity.

immunology↗

bioRxiv2025

Altered Duodenal Mucosa-Associated Microbiota and Immune Profiles in Functional Dyspepsia: A Study of Host-Microbiome Homeostasis

Recent work suggests an altered duodenal mucosa-associated microbiota (MAM) in patients with functional dyspepsia (FD) when compared to outpatient controls, these differences may reflect alterations in host-microbiome homeostasis. Given that specific mucosal immune signatures have been identified in FD, we hypothesised that these changes would be associated with specific microbial changes. We aimed to profile the duodenal MAM to identify microbes associated with known changes in FD mucosal and peripheral immune homeostasis. Duodenal biopsies were collected from 11 asymptomatic outpatient controls and 17 FD patients. Separate biopsies were collected for MAM 16S rRNA amplicon sequencing, histological evaluation, and mucosal lamina propria mononuclear cell (LPMC) isolation. Where available peripheral blood mononuclear cells (PBMC) were isolated from whole blood. PBMC and LPMC populations were analysed for CD4 and CD8 T cell populations by flow cytometry. Initial comparisons of histological and immune measures revealed significant differences between FD and outpatient controls, with decreased villi goblet cells and increased LPMC CD4 Central Memory, LPMC CD8, and PBMC CD4+ Central Memory Th17 in FD compared to controls. While microbiome profiles varied between groups, specific associations with the histological and immunological scoring found that in controls, villi goblet cells correlated positively with Massilia and negatively with Exiguobacterium, while FD patients showed no significant correlations. Additionally, controls exhibited a negative correlation between LPMC CD4 Central Memory and Veillonella, with FD patients showing no significant correlation. Notably, FD patients demonstrated a significant negative correlation between LPMC CD8 and Sulfophobococcus, and a positive correlation between PBMC CD4+ Central Memory Th17 and both Gemella and Fusobacterium. ImportanceWhile several papers have reported the alteration in FD duodenal MAM, study numbers are low and consensus on specific biomarker signatures within the microbiome have not been reached. Our findings contribute to this growing body of evidence, indicating that patients with FD exhibit distinct alterations in duodenal MAM and immune profiles compared to outpatient controls. Furthermore, the immune-microbiome associations present in control populations were absent in FD patients suggesting a loss of host-microbiome homeostasis that may contribute to FD pathophysiology. Our work highlights potential microbial biomarkers which may be a consequence or driver of the mucosal micro-inflammation state which is a characteristic of FD. Future work is required to validate whether these specific microbes are responsible for driving inappropriate host immune responses to inform treatment strategies and assist with disorder diagnosis.

microbiology↗

bioRxiv2019

Secreted microbial metabolites modulate gut immunity and inflammatory tone

Evidence is emerging that microbiome-immune system crosstalk regulates the tenor of host intestinal immunity and predisposition to inflammatory bowel disease (IBD). We identified five NF-{kappa}B suppressive strains affiliated with Clostridium clusters IV, XIVa and XV that independently suppressed secretion of the chemokine IL-8 by peripheral blood mononuclear cells and gut epithelial organoids from healthy human subjects, as well as patients with the predominant IBD subtypes, Crohns disease and ulcerative colitis. The NF-{kappa}B suppressive Clostridium bolteae AHG0001, but not C. bolteae BAA-613, suppressed cytokine-driven inflammatory responses and endoplasmic reticulum stress in gut epithelial organoids derived from Winnie mice that develop spontaneous colitis. This predicted in vivo responses thereby validating a precision medicine approach to treat Winnie colitis and suggesting the microbiome may function as an extrinsic regulator of host immunity. Finally, we identified a novel molecule associated with NF-{kappa}B suppression indicating gut bacteria could be harnessed to develop new therapeutics.

microbiology↗

bioRxiv2018

Enterococcus faecalis AHG0090 is a genetically tractable bacterium and produces a secreted peptidic bioactive that suppresses NF-kB activation in human gut epithelial cells

Enterococcus faecalis is an early coloniser of the human infant gut and contributes to the development of intestinal immunity. To better understand the functional capacity of E. faecalis we constructed a broad host range RP4 mobilisable vector, pEHR513112, that confers chloramphenicol resistance and used a metaparental mating approach to isolate E. faecalis AHG0090 from a faecal sample collected from a healthy human infant. We demonstrated that E. faecalis AHG0090 is genetically tractable and could be manipulated using traditional molecular microbiology approaches. E. faecalis AHG0090 was comparable to the gold-standard anti-inflammatory bacterium Faecalibacterium prausnitzii A2-165 in its ability to suppress cytokine mediated NF-[Kcy]B activation in human gut derived LS174T goblet cell-like and Caco-2 enterocyte-like cell lines. E. faecalis AHG0090 and F. prausnitzii A2-165 produced secreted low molecular weight NF-[Kcy]B suppressive peptidic bioactives. Both bioactives were sensitive to heat and proteinase K treatments although the E. faecalis AHG0090 bioactive was more resilient to both forms of treatment. As expected, E. faecalis AHG0090 suppressed IL-1{beta} induced NF-[Kcy]B-p65 subunit nuclear translocation and expression of the NF-[Kcy]B regulated genes IL-6, IL-8 and CXCL-10. Finally, we determined that E. faecalis AHG0090 is distantly related to other commensal strains and likely encodes niche factors that support effective colonisation of the infant gut.

microbiology↗