Intestinal stem cells (ISCs) reside in intestinal crypts and undergo continual proliferation, self-renewal, and differentiation in order to maintain function of the intestinal epithelium, which is replaced approximately once a week throughout adult life. Precise regulation of cell fate decisions between self-renewal and differentiation is critical for ISC homeostasis and damage response, but the role of chromatin regulation in balancing these decisions remains poorly characterized. Our currently funded K01 focuses on dissecting the genomic regulatory network of Tet1, which catalyzes DNA demethylation and is specifically enriched in ISC populations. Preliminary data from these studies demonstrate that loss of Tet1 results in remarkably rapid crypt hyperplasia and increased ISC function, which occurs within 5 days of Tet1 ablation. The central hypothesis of the proposed study is that Tet1 negatively regulates ISC activity by promoting differentiation. To test this hypothesis and expand on our K01, we will: (1) characterize the phenotypic role of Tet1 in ISC proliferation and differentiation in vivo, at 5 days and 4 weeks post-ablation (Aim 1) and (2) map the Tet1-dependent genomic landscape of 5-hydroxymethylcytosine (5hmC), the primary product of TET1 catalytic activity, in ISCs, progenitors, and post-mitotic cells (Aim 2). Collectively, these Aims will expand on and integrate with our ongoing K01 studies to provide sufficient preliminary data for future, R01-funded investigation of Tet1-mediated mechanisms involved in ISC homeostasis and regeneration.

Public Health Relevance

Intestinal stem cells (ISCs) are critical for maintaining homeostatic digestive and barrier function, and for responding to inflammation or traumatic injury. While a greater understanding of genetic regulation of ISCs holds to potential to identify new therapeutic targets in regenerative medicine, little is known about how the epigenome influences ISC function. In this proposal, we examine the role of Tet1, a master regulator of DNA methylation states, in ISC differentiation and self-renewal, and map its catalytic impacts on chromatin in order to better understand ISC epigenomics.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Small Research Grants (R03)
Project #
7R03DK122111-02
Application #
10193967
Study Section
Kidney, Urologic and Hematologic Diseases D Subcommittee (DDK)
Program Officer
Saslowsky, David E
Project Start
2019-08-01
Project End
2021-07-31
Budget Start
2020-08-01
Budget End
2021-07-31
Support Year
2
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Emory University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322