# Interferon-inducible cell-intrinsic host defense against Chlamydia trachomatis

> **NIH NIH R37** · DUKE UNIVERSITY · 2024 · $541,485

## Abstract

Chlamydia trachomatis is the cause for the most common bacterial sexually transmitted infection.
Commonly referred to as a silent epidemic, C. trachomatis infections in women frequently manifest with
subclinical inflammation, and therefore often go unnoticed and untreated. The infection can persist for
months or years and ultimately cause pelvic inflammatory disease, ectopic pregnancies, and infertility. In
order to establish persistent infections, C. trachomatis must subvert both the innate and the adaptive
branches of the immune system. A central node that connects adaptive and innate immunity to
C. trachomatis is the cytokine gamma-interferon (IFN). This cytokine is produced by innate (ILCs) and
adaptive lymphocytes (T cells) and induces cell-autonomous immunity against Chlamydia in epithelial cells.
To overcome IFN-mediated immunity and replicate inside human epithelial cells, C. trachomatis evolved
counter-defenses specifically adapted to its human host. These C. trachomatis counter-defenses and the
corresponding repertoire of IFN-inducible anti-Chlamydia defense programs are poorly characterized. Our
goal is to decipher this antagonistic interplay between IFN-mediated host defense and chlamydial counter-
defense. We perform unbiased functional genomics screens to identify human IFN-inducible genes (ISGs)
that exert potent anti-Chlamydia defenses. In parallel we employ defined C. trachomatis mutant libraries in
functional bacterial genetic screens to identify C. trachomatis genes that subvert ISG-driven defense
pathways. Taking these approaches, we identified the ubiquitin E3 ligase RNF213 as a human ISG that
eliminates non-human-adapted Chlamydia from human cells through a novel and uncharacterized innate
immune pathway. Reciprocally, we identified the secreted C. trachomatis virulence factor GarD as an
RNF213 antagonist protecting C. trachomatis from RNF213-driven cell-autonomous immunity in human
cells. The mechanism by which this newly discovered RNF213-mediated cell-autonomous defense program
eliminates vacuolar pathogens such as C. trachomatis garD mutant is unknown and will be interrogated
through multidisciplinary approaches in this proposal. Complementary to these studies dissecting RNF213’s
host defense function, we will identify and characterize additional RNF213-independent human cell-
autonomous immune programs directed at Chlamydia and the corresponding counter-immune strategies
employed by C. trachomatis. Using organoid and traditional human cell culture systems as well as novel in
vivo mouse models, we will interrogate the importance of these antagonist host-pathogen relationships in
immune clearance and immunopathology of Chlamydia infections. Such novel insights may guide the
development of new therapeutic or prophylactic treatments or vaccine designs.

## Key facts

- **NIH application ID:** 10798777
- **Project number:** 2R37AI103197-11
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Joern Coers
- **Activity code:** R37 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $541,485
- **Award type:** 2
- **Project period:** 2013-05-15 → 2028-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10798777

## Citation

> US National Institutes of Health, RePORTER application 10798777, Interferon-inducible cell-intrinsic host defense against Chlamydia trachomatis (2R37AI103197-11). Retrieved via AI Analytics 2026-06-01 from https://api.ai-analytics.org/grant/nih/10798777. Licensed CC0.

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