Dataset Information

Acute Experimental Barrier Injury Triggers Ulcerative Colitis-Specific Innate Hyperresponsiveness and Ulcerative Colitis-Type Microbiome Changes in Humans.

ABSTRACT:

Background and aims

The trigger hypothesis opens the possibility of anti-flare initiation therapies by stating that ulcerative colitis (UC) flares originate from inadequate responses to acute mucosal injuries. However, experimental evidence is restricted by a limited use of suitable human models. We thus aimed to investigate the acute mucosal barrier injury responses in humans with and without UC using an experimental injury model.

Methods

A standardized mucosal break was inflicted in the sigmoid colon of 19 patients with UC in endoscopic and histological remission and 20 control subjects. Postinjury responses were assessed repeatedly by high-resolution imaging and sampling to perform Geboes scoring, RNA sequencing, and injury niche microbiota 16S ribosomal RNA gene sequencing.

Results

UC patients had more severe endoscopic postinjury inflammation than did control subjects (P < .01), an elevated modified Geboes score (P < .05), a rapid induction of innate response gene sets (P < .05) and antimicrobial peptides (P < .01), and engagement of neutrophils (P < .01). Innate lymphoid cell type 3 (ILC3) markers were increased preinjury (P < .01), and ILC3 activating cytokines were highly induced postinjury, resulting in an increase in ILC3-type cytokine interleukin-17A. Across groups, the postinjury mucosal microbiome had higher bacterial load (P < .0001) and lower α-diversity (P < .05).

Conclusions

UC patients in remission respond to mucosal breaks by an innate hyperresponse engaging resident regulatory ILC3s and a subsequent adaptive activation. The postinjury inflammatory bowel disease-like microbiota diversity decrease is irrespective of diagnosis, suggesting that the dysbiosis is secondary to host injury responses. We provide a model for the study of flare initiation in the search for antitrigger-directed therapies.

SUBMITTER: Seidelin JB

PROVIDER: S-EPMC8455368 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:The aims of the multi-center Ulcerative Colitis Human Microbiome Project (UCHMP) are to examine the role of the enteric microbiome in causing human ulcerative colitis, specifically the development of pouchitis. Pouchitis is an inflammatory condition of the surgically-created ileoanal pouch that serves as a pseudo-rectum in patients with ulcerative colitis who have undergone a total colectomy. It is a condition unique to ulcerative colitis (UC), as it rarely occurs in non-UC patients who have the same procedure. Within one year, about 50% of patients will develop pouchitis. The condition is almost certainly due to aspects of the pouch microbiota on a background of genetic susceptibility, as most patients respond to treatment with antibiotics. While there have been reports on the microbiota in pouchitis patients, all have been performed after the inflammatory process is initiated, rendering interpretation of the results difficult, as the inflammatory process itself will change the microbiota. Our project is therefore unique and possibly the only opportunity in the role of the enteric microbiome in IBD in a prospective manner, thereby establishing potentially important causal relationships between microbiota structure or function and development of UC. The studies also offer two additional advantages. First, the development of the pouch microbiota can be observed prospectively. Second, the cause of antibiotic treatment failure in some patients with pouchitis may be revealed. The two aims are (1) to identify causal factors in the structure and/or function of the enteric microbiota in the development of pouchitis, and (2) to determine the basis of treatment failure in UC pouchitis patients. Our analyses will include serial measurements of enteric microbial structure (16S rRNA gene-based), function (metagenomics and functional candidate genes), and cultivation, the latter to enhance interpretation of gene sequences derived from metagenomes and targeted gene surveys (either functional or 16S genes). The insights gained from these studies will help us understand the fundamental and causative roles of the enteric microbiome in human inflammatory bowel diseases (IBD). This information will be the basis for developing strategies to restore host-microbial relationships to prevent and treat IBD.