# Site-specific DNA recombinase and A/E pathogen virulence

> **NIH NIH R21** · JOHNS HOPKINS UNIVERSITY · 2020 · $204,688

## Abstract

Project Summary
Foodborne disease is an important health threat and an immense economic burden worldwide. One important
category of causative agents of foodborne diseases is attaching and effacing (A/E) pathogens, which include
human pathogens enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC) and their
murine equivalent Citrobacter rodentium (CR). A/E pathogens share most of their genes and pathogenic
mechanisms to subvert host signaling pathways and immune responses. Particularly, increasing number of
studies demonstrate that A/E pathogen infections cause more severe morbidity and mortality in
immunocompromised hosts. However, the critical host-pathogen interactions in the gut and the mechanism(s)
through which A/E pathogens suppress host immune responses have not been fully understood, especially
under immunocompromised condition. Our recent studies demonstrate that a novel site-specific DNA
recombinase (Ssr) plays a crucial role in CR infection-caused severe morbidity and mortality in
immunocompromised animals. This project aims to elucidate the pathogenic role of Ssr in CR infection-
induced pathogenesis in immunocompromised hosts and the relevance of Ssr in human A/E pathogens. Thus,
we will assess the impact of Ssr on colonic inflammatory response and epithelial integrity during A/E pathogen
infections in Aim 1 and elucidate the molecular mechanism(s) through which Ssr affects virulence gene
expression during A/E pathogen infections in Aim 2. At the conclusion of these studies, we will provide novel
insights into the complex foodborne pathogenesis whereby A/E pathogen virulence is elegantly regulated
during infections. It will also advance our understanding of the sophisticated pathogen-host interactions that
may lead to novel strategies for prevention and treatment of A/E pathogen infections and foodborne diseases,
especially under immunocompromised conditions.

## Key facts

- **NIH application ID:** 9825512
- **Project number:** 5R21AI137719-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Fengyi Wan
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $204,688
- **Award type:** 5
- **Project period:** 2018-11-20 → 2022-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9825512

## Citation

> US National Institutes of Health, RePORTER application 9825512, Site-specific DNA recombinase and A/E pathogen virulence (5R21AI137719-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9825512. Licensed CC0.

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