# Differentiation of pathogenic granzyme A-producing CD4+ T cells in graft-versus-host-disease

> **NIH NIH R56** · PURDUE UNIVERSITY · 2022 · $340,000

## Abstract

PROJECT SUMMARY/ABSTRACT. In graft-versus-host disease (GVHD), a detrimental allo-immune
response that occurs after hematopoietic cell transplant (HCT), donor CD4+ T helper (Th) cells traffic to
multiple organs and their presence in the intestines correlates with worsened clinical prognosis. Despite their
known role in GVHD, how Th cells contribute to intestinal disease remains unclear. My laboratory has recently
identified a novel population of intestinal Th cells that produced the serine protease granzyme A (GrA) which
were critical for intestinal damage and GVHD-associated mortality. However, GrA+ Th cells were dispensable
for the beneficial anti-cancer effects of HCT and therefore represent a promising therapeutic target in GVHD
patients. As effective GrA inhibitors are currently unavailable, defining the molecular mechanisms that lead to
GrA+ Th cell differentiation will uncover novel drug targets for GVHD and provide insight into how pathogenic
Th cells differentiate within the intestines. Here we show that GrA+ Th cells differentiate independently from
other Th lineages and require the integration of both STAT3-dependent and -independent cytokine signaling
pathways for their optimal differentiation during disease. GrA+ Th cells expressed high levels of the STAT3-
induced transcription factors (TFs) BATF and Aiolos that were also required for their development. However,
the STAT-activating cytokines that initiate GrA+ Th cell differentiation and how STAT3-induced TFs guide this
process during GVHD remain undefined. As STAT3 is required for optimal GrA+ Th cell differentiation, we
hypothesize that the STAT3-activating cytokines IL-6 and IL-21 function in parallel with other cytokine/STAT
pathways to initiate GrA+ Th cell differentiation and that a STAT3/BATF/Aiolos network cooperatively promotes
the GrA+ Th cell lineage during aGVHD. To test this hypothesis we will 1) Define the cytokine/STAT signaling
requirements that regulate pathogenic GrA+ Th cell differentiation during GVHD and 2) We will determine how
STAT3/BATF/Aiolos TF network and its downstream effector genes regulate the GrA+ Th cell differentiation
program using combined gene expression, chromatin occupancy analysis and a novel genome-wide CRISPR
screen. Upon completion of these studies we will have defined the inflammatory and transcription factor
requirements that are required for the development of GrA+ Th cells in GVHD and validated these factors as
therapeutic targets in pre-clinical models of disease. This work is highly significant as GrA+ Th cells are a major
driver of intestinal pathology and lethal disease. Therefore, the signaling pathways and genes involved in the
GrA+ Th cell transcriptional signature that we identify may be potential druggable targets for GVHD patients.
These experiments are also highly innovative as we will leverage a novel Gzma-GFP reporter mouse with
cutting-edge sequencing technologies (RNA-Seq, CUT&RUN) to uncover how a STAT3-driven TF network...

## Key facts

- **NIH application ID:** 10664183
- **Project number:** 1R56AI158869-01A1
- **Recipient organization:** PURDUE UNIVERSITY
- **Principal Investigator:** Matthew R Olson
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $340,000
- **Award type:** 1
- **Project period:** 2022-08-10 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10664183

## Citation

> US National Institutes of Health, RePORTER application 10664183, Differentiation of pathogenic granzyme A-producing CD4+ T cells in graft-versus-host-disease (1R56AI158869-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10664183. Licensed CC0.

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