Biology subjects

Morrison, M.

Publications and source records attributed to Morrison, M..

18 recordsLinked to original sources

bioRxiv2026

Microbial Immunomodulatory Function is Altered in Inflammatory Bowel Disease Independent of Microbial Composition

Inflammatory bowel diseases (IBD) are chronic and relapsing immune-mediated conditions in which the NF-{kappa}B and STAT3 signalling pathways play central roles in pathogenesis. While gut microbiome dysbiosis is well described in IBD, its functional consequences, particularly microbial immunomodulatory function (MIF) remain poorly defined. Here, we integrated functional assays with metagenomic profiling to characterise microbiome-driven immune modulation in IBD. Faecal water from non-IBD controls and IBD patients was assessed using NF-{kappa}B and STAT3 reporter systems, alongside high-throughput screening of 2,820 bacterial isolates (94 per subject). Despite minimal differences in overall microbial composition, faecal water from patients with ulcerative colitis (UC) and Crohns disease (CD) significantly increased NF-{kappa}B activity under both basal and TNF-stimulated conditions. Non-IBD controls harboured a higher proportion of suppressive bacterial isolates (21.52%) compared to UC (5.64%) and CD (2.45%), whereas activating isolates were enriched in IBD (UC: 34.47%; CD: 39.36% vs. non-IBD: 5.35%). Similar trends were observed for IL-23-mediated STAT3 activation. Integration of metagenomic and pathway-level analyses identified 24 KEGG pathways associated with inflammatory signalling and faecal lipocalin-2, as well as amino acid, carbohydrate, lipid, cofactor, and nucleotide metabolism. These findings demonstrate that the IBD microbiome is functionally reprogrammed toward pro-inflammatory activity, independent of compositional changes. Defining patient-specific MIF profiles may provide a framework for precision microbiome-based therapeutic strategies in IBD.

microbiology↗

bioRxiv2026

Bioactive produced by Enterococcus Faecalis targets IL-23 signalling and protects against colitis and joint disease

The IL-23/Th17 axis is a central driver of intestinal and spondyloarthritic inflammation, yet upstream regulatory mechanisms linking microbial signals to IL-23 production remain incompletely defined. NF-{kappa}B signalling, particularly via the c-Rel subunit, is a critical transcriptional regulator of IL23A (p19), positioning c-Rel as a nodal checkpoint in mucosal inflammation. Here, we demonstrate that cell-free supernatant derived from Enterococcus faecalis AHG0090 (AHG0090-CS) suppresses c-Rel-dependent IL-23 signalling and attenuates inflammatory pathology across murine models of gut and joint disease. In the ZAP-70 mutant SKG model of spondyloarthritis and ileitis, AHG0090-CS significantly reduced weight loss, joint scores, and histological gut inflammation following curdlan challenge. In the Winnie model of spontaneous colitis, treatment similarly diminished inflammatory cytokine production. Mechanistically, AHG0090-CS reduced IL-23p19 mRNA and protein expression in intestinal tissue and lamina propria myeloid cells, accompanied by decreased nuclear c-Rel intensity. Suppression extended to downstream IL-23-associated cytokines including IL-17A, GM- CSF, MCP-1 and IL-6. In human peripheral blood mononuclear cells and macrophages, AHG0090-CS attenuated LPS-induced IL-23 and pro-inflammatory cytokine production, supporting translational relevance. Collectively, these findings identify microbial modulation of c-Rel-dependent IL-23 signalling as a tractable mechanism to restrain gut-joint inflammation and highlight targeting upstream NF-{kappa}B pathways as a therapeutic strategy in IL-23-driven immune-mediated disease.

microbiology↗

bioRxiv2026

Widespread occurrence of bovine-like and new viruses in wild deer across the United States

Over the past several decades, deer populations in North America have grown considerably, resulting in frequent contact with humans and livestock, and increased potential for pathogen spillover. Despite the importance of pathogen spillover among humans, wildlife, and livestock, the diversity of viruses present in deer remains largely unknown. Using a metagenomic high-throughput sequencing approach, we characterized viral communities in the upper respiratory tracts of live mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) captured at fourteen study sites in nine states across the United States. We identified vertebrate-infecting viruses in both deer species at all but two of the study sites, located in Illinois and Utah. Viral richness did not vary among species or study sites. However, viral community composition was different across study sites but not among deer species. Amongst the detected viral sequences, several originate from or were closely related to viruses previously described in humans (e.g., severe acute respiratory syndrome coronavirus 2) and livestock (e.g., bovine-like coronavirus). We also documented viruses recently discovered in deer, such as CHeRI orbivirus 1. Finally, we identified several new putative viruses in the Picornaviridae, Rhabdoviridae and Tobaniviridae families, including a novel Aphthovirus related to bovine rhinitis A virus in both deer species, across seven states and nine study sites. Our findings expand the understanding of viral diversity in two deer species across the United States, providing important insights for managing pathogens at the wildlife, livestock, and human interface.

microbiology↗

bioRxiv2026

EventHorizon: A Foundation Model for Clinical Flow Cytometry

Flow cytometry is an essential tool for diagnosis of hematologic malignancies, but existing clinical workflows are highly dependent on expert manual interpretation. Existing machine learning approaches typically require extensive labeled data and are sensitive to variability in panel design, instrumentation, and laboratory workflows, limiting their generalizability. We present EventHorizon, a self-supervised foundation model for clinical flow cytometry that produces unified specimen-level representations from heterogeneous multi-panel data. EventHorizon employs a two-stage hierarchical transformer architecture with marker-aware tokenization, enabling seamless integration of cells measured across different antibody panels into a single shared latent space. We pre-train the model using a DINO-inspired self-distillation strategy with a variety of flow cytometry-specific augmentations on a dataset of more than 100,000 clinical specimens across 17 distinct panels. We evaluate the resulting embeddings on three clinically relevant classification tasks spanning common and rare panels, demonstrating that simple k-nearest neighbor probing of frozen EventHorizon embeddings achieves performance comparable to a fully supervised baseline model and a prior panel-specific self-supervised model. To ensure EventHorizon is not simply shortcut learning on features such as the markers/panels run for a given specimen, we perform a graph-theoretic analysis of EventHorizons latent space which argues that specimen embeddings are organized primarily by biological diagnosis. Taken together, these results demonstrate that EventHorizon produces biologically meaningful, panel-agnostic specimen representations from clinical flow cytometry data which, with further development and validation, could provide a potential basis for scalable, reproducible diagnostic support across diverse clinical laboratory settings.

bioinformatics↗

bioRxiv2025

A molecular inventory of the faecal microbiomes of 23 marsupial species

Despite the recent expansion of culture-independent analyses of animal faecal microbiomes, many lineages remain understudied. Marsupials represent one such group, where despite their iconic status, direct sequencing-based analyses remain limited. Here we present a metagenomic and metabolomic exploration of the faecal microbiomes of 23 Diprotodontia marsupials, producing a reference set of 3,868 prokaryotic and 12,142 viral metagenome-assembled genomes, the majority (>80%) of which represent novel species. As with other animals, host phylogeny is the primary driver of microbiome composition, including distinct profiles for two eucalyptus folivore specialists (koalas and southern greater gliders), suggesting independent solutions to this challenging diet. Expansion of several bacterial and viral lineages were observed in these and other marsupial hosts that may provide adaptive benefits. Antimicrobial resistance genes were significantly more prevalent in captive than wild animals likely reflecting human interaction. This molecular dataset contributes to our ongoing understanding of animal faecal microbiomes. Impact statementDespite their ecological and evolutionary importance, marsupials remain underrepresented in microbiome research. Here, we present the most extensive faecal microbiome dataset to date for this group, encompassing metagenomic, metabolomic, and proximity ligation data from 23 marsupial species. As in other animals, we find the microbial community structure reflects the host species, and some marsupials carry expanded sets of certain microbial lineages indicative of within-host evolution. This work substantially expands the genomic landscape of host-associated microbes and viruses in a poorly studied mammalian clade. Data summaryRaw read data, prokaryotic MAGs [≥]50% complete with [≤]10% contamination are available via the European Nucleotide Archive under project PRJEB89408. The full set of viral genomes, clustered protein database and metabolite data (raw and processed) are available via https://doi.org/10.48610/14e37e9. Prokaryotic MAGs are also available via https://figshare.com/s/87443d80817f57aadc16.

microbiology↗

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↗

bioRxiv2024

Metagenomic analysis of marsupial gut microbiomes provides a genetic basis for the low methane economy

The potent greenhouse gas methane is an end-product of plant biomass digestion by gut microbiota, though the amount produced and/or released varies among herbivorous animals. On a per unit of feed basis, macropodid marsupials (e.g. kangaroos) are widely thought to be low methane-emitting herbivores compared to high methane-producing ruminant livestock. How the gut microbiome contributes to the low methane status of marsupials is not well understood but of high potential value for a low methane economy. Here, we analyse the faecal metagenomes of 14 different marsupial species and 1,394 derived metagenome-assembled genomes (MAGs), focusing on the functional distinction of the bacterial and archaeal communities compared to ruminant faecal microbiomes. Though composition and function of the marsupial gut microbiome considerably varied across and within animal species, there was a clear host-associated bacterial signature for the community that differed significantly between marsupial hosts and compared to ruminants. Of particular note was a range of Bacteroidota, Campylobacterota, Desulfobacterota, Pseudomonadota and Verrucomicrobiota species that were enriched in marsupials and encode H2-uptake hydrogenases that mediate hydrogenotrophic respiration. Additionally, in support of an enrichment of electron sinks, enzymes for butyrate, propionate, and glutamate production, as well as nitrate, nitrite, and fumarate respiration were enriched in marsupials. Collectively, these data suggest that, by favoring an enrichment of alternate hydrogen sinks of bacterial origin, the low methane phenotype reported for marsupials is feasible and offers a genetic basis to pursue reductions of livestock methane emissions.

microbiology↗

bioRxiv2024

Copper induces p53 unfolding in cancer cells, resulting in invasion and chemoresistance

Copper has been shown to play an important role in cancers, enhancing cell proliferation, remodelling the microenvironment and enhancing the function of oncogenes. Here we show that copper turns the tumour suppressor p53 protein into a pro-oncogenic protein. Mutations in the TP53 gene often lead to expression of various mutant p53 proteins. Mutant proteins often lose some or all wild type function and gain novel pro-tumourigenic functions, which can be partially attributed to protein unfolding. Here we show that copper accumulates in tumours, unfolds WTp53 and promotes chemoresistance. Unfolding of WT p53 results in interaction with mutant p53-specific interacting proteins TAp63 and Ago2 and promotes invasion. Interestingly, partially-functional p53 mutants that are frequently observed in lung cancers, are more affected by copper than WTp53. Our results suggest that small increases in copper impair WT p53 function and augment mutant p53 function, which could partially be restored by the chelator Trien.

cancer biology↗

bioRxiv2023

Toxicogenomic analysis of the carcinogenic potential of plastic additives

Plastics are the most prevalent human-made substance in the world and are ubiquitous throughout all ecosystems. Microscopic plastic particles are routinely ingested and inhaled by humans and other organisms. Despite the frequency of plastic exposures, little is known about their health consequences. Of particular concern are plastic additives -chemical compounds that are mixed into plastics to improve functionality or are unintentionally acquired during plastic production and use. Additives are loosely bound to the plastic polymer and may be released during plastic exposures. These compounds may pose health concerns, such as cancer, but little is known about the potential impact of these chemicals on health. To better understand the health effects of plastic additives, we performed an integrated toxicogenomic analysis on 2,712 additives, focusing on cancer as a well-studied toxicological endpoint. Screening these substances across three chemical databases revealed two key observations: 1) over 150 plastic additives have known carcinogenicity and 2) the majority ([~]90%) of plastic additives lack data on carcinogenic endpoints. Analyses of additive usage patterns pinpointed specific polymers, functions, and products in which carcinogenic additives reside. Based on published chemical-gene interactions, both carcinogenic additives and additives with unknown carcinogenicity impacted similar biological pathways. The predominant pathways involved DNA damage, apoptosis, immune response, viral diseases, and cancer. This study underscores the urgent need for systematic and comprehensive carcinogenicity assessment of plastic additives and regulatory responses to mitigate the potential health risks of plastic exposure.

pharmacology and toxicology↗

bioRxiv2023

Spatiotemporal Dynamics of Vcam1 Regulates Cholangiocarcinoma Mass Expansion and Tumor Dissemination under Growth-suppressive Peritumoral Myofibroblasts

Intrahepatic cholangiocarcinoma (iCCA) is characterized by its highly desmoplastic stroma. Myofibroblasts (MFs) are present both within the tumor mass (intratumoral MFs, iMFs) and at the tumor border (peritumoral MFs, pMFs). Using a spheroid-based coculture system, we show that the initial iCCA-pMF contact is growth suppressive to the tumor cells. However, prolonged iCCA-pMF interaction elicits significant tumor cell invasion and dissemination. We find that vascular cell adhesion molecule-1 (Vcam1) level is elevated in tumor cells in contact with pMFs but low in disseminated tumor cells both in vitro and in vivo. A gene regulatory network analysis of mouse and patient iCCA tumors and Vcam1 knockout (Vcam1KO) demonstrate a heavy involvement of Vcam1 in epithelial-to-mesenchymal transition. While Vcam1KO has only a limited impact on tumor cell growth in their monoculture, Vcam1KO spheroids exhibit instant dissemination and a severe growth defect when cocultured with pMFs. When transplanted into the liver, Vcam1KO iCCA cells show a similar increase in dissemination but a significant defect in establishing primary and metastatic tumors. Incomplete blocking of Vcam1 in vivo reduces the size but increase the number of metastatic lesions. Overall, our study shows a spatiotemporal regulation of iCCA growth and dissemination by pMFs in a Vcam1-dependent manner.

cancer biology↗

bioRxiv2023

The maternal microbiome regulates infant respiratory disease susceptibility via intestinal Flt3L expression and plasmacytoid dendritic cell hematopoiesis

Severe lower respiratory infection (sLRI) are a major cause of infant morbidity and mortality, and predispose to later chronic respiratory diseases such as asthma. Poor maternal diet during pregnancy is a risk factor for sLRI in the offspring. Here we demonstrate in mice that a maternal low-fibre diet (LFD) disrupts plasmacytoid and conventional dendritic cell (DC) hematopoiesis in the offspring, predisposing to sLRI and subsequent asthma. The LFD alters the composition of the maternal milk microbiome and assembling infant gut microbiome, ablating the induction of a developmental wave of the non-redundant DC growth factor Flt3L by neonatal intestinal epithelial cells. Therapy with a propionate-producing bacteria isolated from the milk of high-fibre diet-fed mothers, or supplementation with propionate, confers protection against sLRI by restoring gut Flt3L expression and pDC hematopoiesis. Our findings identify a microbiome-dependent Flt3L axis in the gut that regulates pDC hematopoiesis in early life and confers disease resistance. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=51 SRC="FIGDIR/small/522516v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1a39990org.highwire.dtl.DTLVardef@1b6fe67org.highwire.dtl.DTLVardef@f8440dorg.highwire.dtl.DTLVardef@13bc67e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

How many ecological niches are defined by the superabundant marine microbe Prochlorococcus?

Determining the identities, frequencies, and memberships of ecotypes in Prochlorococcus and other superabundant microbes (SAMs) is essential to studies of their evolution and ecology. This is challenging, however, because the extremely large population sizes of SAMs likely cause violations of foundational assumptions made by standard methods used in molecular evolution and phylogenetics. Here we present a tree-free likelihood method to identify ecotypes, which we define as populations with genome sequences whose high similarity is maintained by purifying selection. We applied the method to 96 genomes of the superabundant marine cyanobacterium Prochlorococcus and find that this sample is comprised of about 24 ecotypes, substantially more than the five major ecotypes that are generally recognized. The method presented here may prove useful with other superabundant microbes.

evolutionary biology↗

bioRxiv2021

Dominant Effect Of Host Genetics On Skin Microbiota Composition In Homeostasis And Wound Healing

Animal microbiota have complex interactions with hosts and environment that determines its composition. Yet the ability of hosts to determine their microbiota composition is less well studied. In this study, to investigate the role host genetics in determining skin microbiota, we used 30 different mouse strains from the recombinant inbred panel, the Collaborative Cross. Murine skin microbiota composition was strongly dependent on murine strain with > 50% of the variation explained by murine strain. In particular, a quantitative trait locus on chromosome 4 associates both with Staphylococcus abundance and principal-component multi-trait analyses. Additionally, excisional wound associated changes in microbiota composition were not uniform across mouse strains and were host-specific, the genetic background accounting for about 40% of the variation in microbiota. Genetic background also had the highest effect on the healing speed of wounds accounting for over 50% of the variation while mouse age and microbiota composition change accounted only for 20% and 5% of the healing speed despite reaching statistical significance. In conclusion, host genetics has a significant impact on the skin microbiota composition during both homeostasis and wound healing. These findings have long reaching implications in our understanding of associations between microbiota dysbiosis and disease.

systems biology↗

bioRxiv2020

Insights into the catalytic properties of the mitochondrial rhomboid protease PARL

The rhomboid protease PARL is a critical regulator of mitochondrial homeostasis through its cleavage of substrates such as PINK1, PGAM5, and Smac, which have crucial roles in mitochondrial quality control and apoptosis. To gain insight into the catalytic properties of the PARL protease, we expressed human PARL in yeast and used FRET-based kinetic assays to measure proteolytic activity in vitro. We show PARL activity in detergent is enhanced by cardiolipin. Significantly higher turnover rates are observed for PARL reconstituted in proteoliposomes, with Smac being cleaved most rapidly at a rate of 1 min-1. PGAM5 is cleaved with the highest efficiency compared to PINK1 and Smac. In proteoliposomes, a truncated {beta}-cleavage form of PARL is more active than the full-length enzyme for hydrolysis of PINK1, PGAM5 and Smac. Multiplex substrate profiling reveals a substrate preference for PARL with a bulky side chain Phe in P1, which is distinct from small side chain residues typically found with bacterial rhomboid proteases. This study using recombinant PARL provides fundamental insights into its catalytic activity and substrate preferences.

biochemistry↗

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↗

bioRxiv2019

Theoretical investigation of a genetic switch for metabolic adaptation

Membrane transporters carry key metabolites through the cell membrane and, from a resource standpoint, are hypothesized to be produced when necessary. The expression of membrane transporters in metabolic pathways is often upregulated by the transporter substrate. In E. coli, such systems include for example the lacY, araFGH, and xylFGH genes, which encode for lactose, arabinose, and xylose transporters, respectively. As a case study of a minimal system, we build a generalizable physical model of the xapABR genetic circuit, which features a regulatory feedback loop through membrane transport (positive feedback) and enzymatic degradation (negative feedback) of an inducer. Dynamical systems analysis and stochastic simulations show that the membrane transport makes the model system bistable in certain parameter regimes. Thus, it serves as a genetic "on-off" switch, enabling the cell to only produce a set of metabolic enzymes when the corresponding metabolite is present in large amounts. We find that the negative feedback from the degradation enzyme does not significantly disturb the positive feedback from the membrane transporter. We investigate hysteresis in the switching and discuss the role of cooperativity and multiple binding sites in the model circuit. Fundamentally, this work explores how a stable genetic switch for a set of enzymes is obtained from transcriptional auto-activation of a membrane transporter through its substrate.

biophysics↗

bioRxiv2019

Shotgun metagenomics reveals an enrichment of potentially cross-reactive bacterial epitopes in ankylosing spondylitis patients, as well as the effects of TNFi therapy and the host’s genotype upon microbiome composition

Diverse evidence including clinical, genetic and microbiome studies support a major role of the gut microbiome in the common immune-mediated arthropathy, ankylosing spondylitis (AS). To further investigate this we performed metagenomic analysis of a case-control cohort of 250 Han-Chinese subjects. Previous reports of gut dysbiosis in AS were re-confirmed and several notable bacterial species and functional categories were differentially abundant. TNF-inhibitor (TNFi) therapy at least partially restored the perturbed microbiome observed in untreated AS cases to that of healthy controls, including several important bacterial species that have been previously associated with AS and other related diseases. Enrichment of bacterial peptides homologous to HLA-B27-presented epitopes was observed in the stools of AS patients, suggesting that either HLA-B27 fails to clear these or that they are involved in driving HLA-B27-associated immune reactions. TNFi therapy of AS patients was also associated with a reduction of potentially arthritogenic bacterial peptides, relative to untreated patients. An AS-associated SNP in RUNX3 significantly influenced the microbiome in two independent cohorts, highlighting a host genotype (other than HLA-B27) potentially influencing AS via the microbiome. These findings emphasise the key role that the gut microbiome plays in driving the pathogenesis of AS.

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↗