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Newman, K. L.

Publications and source records attributed to Newman, K. L..

2 recordsLinked to original sources

Miniature bioreactor arrays for modeling functional and structural dysbiosis in inflammatory bowel disease

Alterations in the gut microbiota, known as gut dysbiosis, are associated with inflammatory bowel disease (IBD). There is a need for model systems that can recapitulate the IBD gut microbiome to better understand the mechanistic impact of differences in microbiota composition and its functional consequences in a controlled laboratory setting. To this end, we introduced fecal samples from patients with Crohns disease (CD) and ulcerative colitis (UC), as well as from healthy control subjects, to miniature bioreactor arrays (MBRAs) and analyzed the microbial communities over time. We then performed two functional assessments. First, we evaluated the colitogenic potential of the CD microbiotas in genetically susceptible germ-free IL-10-deficient mice and found that colitogenic capacity was preserved in a bioreactor-cultivated CD microbiota. Second, we tested impaired colonization resistance against Clostridioides difficile in UC microbiotas using the MBRA system and found that UC microbiotas were innately susceptible to C. difficile colonization while healthy microbiotas were resistant, consistent with what is seen clinically. Overall, our results demonstrate that IBD microbiotas perform comparably to healthy donor microbiotas in the MBRA system, successfully recapitulating microbial structure while preserving IBD-specific functional characteristics. These findings establish a foundation for further mechanistic research into the IBD microbiota using MBRAs.

microbiology↗

Immune phenotype-guided identification of disease-associated pathobionts in Crohn's disease

Aberrant immune activation within the gut mucosa and gut dysbiosis have been implicated in the pathogenesis of Crohns disease (CD). However, the specific immune responses triggered by dysbiotic microbiota, as well as the bacteria responsible for this activation, remain incompletely understood. Here, using the human microbiota-associated (HMA) mouse system, we demonstrated that colonization with dysbiotic gut microbiota from CD patients specifically induces the accumulation of mononuclear phagocytes, which may drive an interleukin-1 (IL-1)-driven inflammatory signature. Moreover, we identified pathobiont strains with a potent IL-1{beta}-inducing capacity, termed IL-1{beta}-inducing pathobionts (IBIP). Isolated IBIP strains exhibit genetic and functional similarities to adherent-invasive Escherichia coli but harbor unique virulence-associated genes. Colonization with the IBIP E. coli strain exacerbated experimental colitis in an IL-1 signal-dependent manner. Notably, the colonization of IBIP E. coli can be detected by measuring the levels of specific immunoglobulin A (IgA) in their stool samples. Moreover, the level of IBIP-reactive IgA in stool may serve as a predictive biomarker for treatment response to anti-TNF therapies in treatment-naive pediatric CD patients. Altogether, IBIP colonization could help identify CD patients with inflammatory dysbiosis who are likely to be refractory to anti-TNF therapies.

immunology↗