# RP3: Targeting ATG gene-dependent immunity for novel anti-infective therapeutics

> **NIH NIH U19** · UT SOUTHWESTERN MEDICAL CENTER · 2021 · $1,177,671

## Abstract

PROJECT SUMMARY – RP3: The goal of RP3 is to define and pharmacologically target intracellular immune 
mechanisms utilizing autophagy (Atg) genes (but not degradative autophagy) to control infection and 
inflammation. We discovered these processes in experiments designed to understand the anti-infective 
mechanisms of IFNγ, a cytokine essential in both humans and mice for macrophage-mediated resistance to 
viruses, bacteria, and parasites. IFNγ is used to treat chronic granulomatous disease and osteopetrosis, but 
other uses of IFNγ have been limited by toxicity, a fact generally attributed to IFNγ inducing the expression of a 
very large number of pro-inflammatory genes. We theorized that new therapeutics might be generated by 
defining the effector mechanisms responsible for the potent effects of IFNγ, and then selectively stimulating 
these mechanisms to generate Atg gene-directed broad-spectrum anti-infectives. This led to the discovery that 
IFNγ triggers Atg gene-dependent immunity against T. gondii and norovirus (NoV) infection using the same set 
of Atg genes (Atg5, Atg7, Atg16L1, Atg12), but not Atg14 or degradative autophagy. The fact that Atg gene- 
dependent mechanism(s) controlled two phylogenetically distinct pathogens suggested to us that we might be 
able to make compounds that are effective against a broad range of pathogens. During the first CETR funding 
period we confirmed this prediction by identifying Atg gene-directed broad-spectrum anti-infective compounds 
with activity against norovirus, salmonella, Mycobacterium tuberculosis and Toxoplasma gondii. This discovery 
was complemented by discoveries of the role of Atg genes in the regulation of inflammation. RP3 focuses on the 
Caliciviridae (most importantly NoVs) which are priority pathogens, causing >90% of the epidemic non-bacterial 
gastroenteritis in the world. We discovered murine NoV (MNoV) and cultured NoVs for the first time, providing a 
preclinical model in laboratory mice and allowing discovery of Atg gene-dependent immunity. Studies of human 
NoV (HNoV) infection had been limited until it was recently found that HNoV grows in cells differentiated from 
biopsy-derived human colonic stem cells. This, together with the discovery that MNoV grows robustly in human 
cells expressing the proper receptor, and that Atg gene-dependent immunity operates against both T. gondii and 
MNoV in human cells strongly argues that these mechanisms are evolutionarily conserved and provide the tools 
to identify compounds relevant to a major human disease via the following aims: Aim 1: Develop Atg gene- 
directed broad spectrum anti-infective compounds; Aim 2: Define the molecular basis of Atg gene- 
dependent IFNγ-induced control of norovirus replication, and identify targets and lead compounds that 
trigger this form of intracellular immunity; Aim 3: Define the molecular basis for the regulation of IFNγ 
responses by Atg genes and identify lead compounds that up-regulate specific I...

## Key facts

- **NIH application ID:** 10144387
- **Project number:** 5U19AI142784-03
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** Seungmin Hwang
- **Activity code:** U19 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $1,177,671
- **Award type:** 5
- **Project period:** 2020-03-01 → 2024-02-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10144387

## Citation

> US National Institutes of Health, RePORTER application 10144387, RP3: Targeting ATG gene-dependent immunity for novel anti-infective therapeutics (5U19AI142784-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10144387. Licensed CC0.

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