# In Vivo Prevention of Murine GVHD > **NIH NIH R37** · UNIVERSITY OF MINNESOTA · 2024 · $589,718 ## Abstract Abstract Our overall goals are focus on the prevention and treatment of graft-vs-host disease (GVHD) via innate lymphoid type 2 cell (ILC2) anti-inflammatory and tissue reparative properties. We found that host ILC2s in are eliminated by total body irradiation {TBI} or chemotherapy and remain depleted for at >/=90 days. This finding is highly relevant as there is an inverse correlation between peripheral blood activated ILC2s and GVHD. As such. we sought to determine whether supplemental infusion of mature donor ILC2s could be used to prevent murine GVHD. We showed for the first time that donor ILC2s could prevent or partially treat GVHD in an amphiregulin (AREG) dependent process. Whether AREG or ILC2 direct contact with intestinal stem cells {ISC) supports small intestine epithelial cell repair in TBI treated mice or organoids is unknown. Additionally, third-party ILC2 infusion also significanUy reduced murine GVHD lethality. lmportanUy for translational purposes, we found ILC2s to be relatively steroid resistant. Peri-BMT {bone marrow transplant) IL-33 increased ST2/IL33R+ ILC2s at BMT day 0 and reduced GVHD. Ko mice had accelerated GVHD; IL-33 given pre-BMT prevented the full lLC2 loss. IL-33 ko recipients have hypo-proliferative epithelial cells, reduced ISCs and Paneth cells, and smaller crypt height and numbers. Ex vivo intestine organoid culture modeling revealed that IL-33 coordinated regeneration by inducing epidermal growth factor (EGF), significantly reduced by TBI. EGF restored ISC deficiency, uncovering a gut repair IL-33/EGF loop between ISCs and Paneth cells. Donor IL-13 ko ILC2s or host IL 13Ra ko mice had reduced GVHD. ILC2 IL 13 supports both ST2+ tuft cells and goblet cells. Tuft cells produce IL-25 driving ILC2 production and survival. TBI markedly reduced tuft cells for :!:38 days and ko recipients had a striking increase in GVHD. When given to wildtype mice exogenous IL-25 significantly reduced GVHD. Consequences of ko of tuft cells (and ILC2s) on donor T cell expansion, trafficking and function are unknown. The role of IL-25 and IL 17RB has not been examined. We will address the dynamics and interplay between ILC2, IL-33 and host intestinal cells (tuft cells, ISCs, Paneth cells) after TBI and during GVHD. Aim 1 will test the hypothesis that: Donor ILC2 repopulation fails due to destruction of ILC2 BM niche that supports ILC2s. In vitro pre-lLC2 differentiation, maturation and expansion ± proinflammatory cytokines and ILC2 supporting cytokines will be studied. GATA3-GFPhi pre-lLC2s/mature ILC2s transfer into lethally irradiated congenic BMT recipients will provide data on the differential ability to repopulate the BM. If the BM cannot support pre-lLC2s/lLC2s, we will study stem cell deficient mice. Aim 2 will test the hypothesis that: Pre-lLC2s/lLC2s and their secreted products have direct effects on intestinal cell subsets. Intestinal organoid cultures from wild-type and IL-33 ko mice with syngeneic Tregs and ILC2s will me... ## Key facts - **NIH application ID:** 10866573 - **Project number:** 5R37AI034495-32 - **Recipient organization:** UNIVERSITY OF MINNESOTA - **Principal Investigator:** Bruce R Blazar - **Activity code:** R37 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2024 - **Award amount:** $589,718 - **Award type:** 5 - **Project period:** 2022-07-01 → 2027-06-30 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10866573 ## Citation > US National Institutes of Health, RePORTER application 10866573, In Vivo Prevention of Murine GVHD (5R37AI034495-32). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10866573. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*