The gastrointestinal epithelium is one of the most proliferative/regenerative tissues in adult organisms pointing to the existence of an intestinal stem cell (ISC) pool. Progress towards identification, isolation, and study of a self-renewing, multipotential intestinal stem cell has been hindered thus far due to the following factors: a) the lack of specific intestinal stem cell markers, b) the lack of a full understanding of the molecular mechanisms that the intestinal stem cell uses to choose between self-maintenance or differentiation, and c) a lack of methods to isolate intestinal stem cells and characterize them at the molecular and physiologic level. Identifying the intestinal stem cell and defining the molecular mechanisms that underlie intestinal stem/progenitor cell potency is critical to the understanding of both normal and dysregulated intestinal function. Recently, the SOX-family of transcription factors has been implicated in modulating stem or progenitor cell potency and competence - the ability to self-renew and differentiate into all cell types of the tissue/organ. The mRNAs for several SOX family members have been detected in both the adult small intestine and colon. With the exception of SOX9 the cellular localization and role of SOX factors in the intestine remain largely unknown. SOX9 has been localized to what is widely thought to be the stem cell niche in the small intestine. The broad expression pattern of SOX9 at the base of the crypt suggests it is a biomarker of both stem and progenitor cells. We have recently demonstrated that SOX4 and SOX7 expression is more restricted in small intestine to a very small population of cells in the small intestine stem cell niche. Thus, the central hypothesis of this study is that specific SOX proteins are biomarkers of stem and progenitor crypt cells in the intestine and play a critical role in maintaining stem/progenitor cell potency and competence. To test this hypothesis I propose the following aims: 1) To establish an expression profile for SOX family members in stem and progenitor cells, 2) To use chromatin immunoprecipitation (ChIP) and a novel Sox9EGFP reporter mouse to define the functional role of SOX9. 3) To develop a dual purpose red- fluorescent protein/lineage marking mouse model (Sox4Tomato/CreERT2) to assay 'sternness'of Sox4 [sic] - expressing cells. These studies are critical to enhance our understanding and treatment of intestinal injury and repair, congenital disorders, and cancer.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01DK080181-03
Application #
7790630
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Podskalny, Judith M,
Project Start
2008-04-01
Project End
2011-03-31
Budget Start
2010-04-01
Budget End
2011-03-31
Support Year
3
Fiscal Year
2010
Total Cost
$128,308
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Van Landeghem, Laurianne; Santoro, M Agostina; Mah, Amanda T et al. (2015) IGF1 stimulates crypt expansion via differential activation of 2 intestinal stem cell populations. FASEB J 29:2828-42
Roche, Kyle C; Gracz, Adam D; Liu, Xiao Fu et al. (2015) SOX9 maintains reserve stem cells and preserves radioresistance in mouse small intestine. Gastroenterology 149:1553-1563.e10
Gracz, Adam D; Fuller, Megan K; Wang, Fengchao et al. (2013) Brief report: CD24 and CD44 mark human intestinal epithelial cell populations with characteristics of active and facultative stem cells. Stem Cells 31:2024-30
Van Landeghem, Laurianne; Santoro, M Agostina; Krebs, Adrienne E et al. (2012) Activation of two distinct Sox9-EGFP-expressing intestinal stem cell populations during crypt regeneration after irradiation. Am J Physiol Gastrointest Liver Physiol 302:G1111-32
Ramalingam, S; Daughtridge, G W; Johnston, M J et al. (2012) Distinct levels of Sox9 expression mark colon epithelial stem cells that form colonoids in culture. Am J Physiol Gastrointest Liver Physiol 302:G10-20
Gracz, A D; Puthoff, B J; Magness, S T (2012) Identification, isolation, and culture of intestinal epithelial stem cells from murine intestine. Methods Mol Biol 879:89-107
Gracz, A D; Magness, S T (2011) Sry-box (Sox) transcription factors in gastrointestinal physiology and disease. Am J Physiol Gastrointest Liver Physiol 300:G503-15
Gracz, Adam D; Ramalingam, Sendhilnathan; Magness, Scott T (2010) Sox9 expression marks a subset of CD24-expressing small intestine epithelial stem cells that form organoids in vitro. Am J Physiol Gastrointest Liver Physiol 298:G590-600
Formeister, Eric J; Sionas, Ayn L; Lorance, David K et al. (2009) Distinct SOX9 levels differentially mark stem/progenitor populations and enteroendocrine cells of the small intestine epithelium. Am J Physiol Gastrointest Liver Physiol 296:G1108-18