Epithelial talin-1 protects mice from Citrobacter rodentium-induced colitis by restricting bacterial crypt intrusion and enhancing T cell immunity

ABSTRACT

Pathogenic enteric Escherichia coli present a significant burden to global health. Food-borne enteropathogenic E. coli (EPEC) and Shiga toxin-producing E. coli (STEC) utilize attaching and effacing (A/E) lesions and actin-dense pedestal formation to colonize the gastrointestinal tract. Talin-1 is a large structural protein that links the actin cytoskeleton to the extracellular matrix though direct influence on integrins. Here we show that mice lacking talin-1 in intestinal epithelial cells (Tln1^Δepi) have heightened susceptibility to colonic disease caused by the A/E murine pathogen Citrobacter rodentium. Tln1^Δepi mice exhibit decreased survival, and increased colonization, colon weight, and histologic colitis compared to littermate Tln1^fl/fl controls. These findings were associated with decreased actin polymerization and increased infiltration of innate myeloperoxidase-expressing immune cells, confirmed as neutrophils by flow cytometry, but more bacterial dissemination deep into colonic crypts. Further evaluation of the immune population recruited to the mucosa in response to C. rodentium revealed that loss of Tln1 in colonic epithelial cells (CECs) results in impaired recruitment and activation of T cells. C. rodentium infection-induced colonic mucosal hyperplasia was exacerbated in Tln1^Δepi mice compared to littermate controls. We demonstrate that this is associated with decreased CEC apoptosis and crowding of proliferating cells in the base of the glands. Taken together, talin-1 expression by CECs is important in the regulation of both epithelial renewal and the inflammatory T cell response in the setting of colitis caused by C. rodentium, suggesting that this protein functions in CECs to limit, rather than contribute to the pathogenesis of this enteric infection.

KEYWORDS:

• Talin
• C. rodentium
• colonic epithelial cells
• neutrophils
• T cells
• colon organoids
• fecal microbiome
• flow cytometry
• crypt hyperplasia

Acknowledgments

We kindly thank Roy Zent for providing the C57BL/6 Tln1^fl/fl mice. We would like to thank the Vanderbilt Digestive Disease Research Center (DDRC) Tissue Morphology Subcore for help with tissue immunostaining.

Author contributions

YLL, APG, and KTW conceived of the study; DPB contributed to methodology; YLL, MMA, DPB, TMS, KJW, KMM, JJ, JAG, AGD, MBP, and SZ conducted the investigation; YLL conducted the formal analysis; YLL contributed to visualization during the studies and wrote the original draft of the manuscript; YLL, APG, and KTW reviewed and edited the manuscript; APG and KTW supervised conducting of the study; and KTW acquired funding for the study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article. The 16S rRNA sequencing of the fecal microbiota has been deposited on the Sequence Read Archive website with the BioProject ID: PRJNA946899 at this URL: https://www.ncbi.nlm.nih.gov/bioproject/PRJNA946899.

Additional information

Funding

This work was supported by: NIH Grants R01DK128200, P01CA028842, P01CA116087, U.S. Department of Veterans Affairs Merit Review Grant I01C×00217, U.S. Department of Defense Grant W81×WH-21-1-0617, Crohn’s & Colitis Foundation Senior Research Award 703003, a gift from Cure for IBD, the James Rowen Fund, and the Thomas F. Frist Sr. Endowment (all to K.T.W.) and core services from the Vanderbilt University Medical Center Digestive Disease Research Center funded by NIH Grant P30DK058404 and the Vanderbilt-Ingram Cancer Center supported by NIH grant P30CA068485. YLL was supported by NIH Grant T32AI138932 and KMM was supported by NIH grant T32CA009592.