Through the proposed training in his K01, I will pursue the additional mentorship that I need and the additional research time to enhance my passion for intestinal epithelial biology. During this award period I will have the opportunity to acquire and refine fundamental skills of becoming a developed scientist. Career development will be fostered through twice-weekly meetings with Dr. Rustgi, convening an expert interdisciplinary advisory committee twice annually, and taking advantage of opportunities in career and professional development through UPenn, the NIH and the AGA. These skills include (but are not limited to) manuscript and grant preparation, lab meeting presentations, participation in the seminars and courses described herein, and presentations at international research conferences (DDW, Keystone). Training will also entail course-work in biostatistics (two semesters), short courses in RNA biology and basic bioinformatics, ongoing training in bioethics, weekly participation in the seminar series (where Iwill meet visiting professors), journal clubs (presentations semi-annually), and twice yearly floo lab meetings through the NIDDK P30 Center for Molecular Studies in Digestive and Liver Diseases and Division of Gastroenterology. The overarching hypothesis of this project is the following: LIN28B plays a critical role in regulating growth and proliferation in the intestinal epithelium via cooperation with c-MYC, with key roles for intestine stem cell (ISC) maintenance. Two potential interrelated mechanisms will be explored: 1) LIN28B binds to target mRNAs associated with cellular growth and cooperates with the transcription factor c-MYC, which is a master regulator of cell growth. and 2) LIN28B affects the maintenance of the ISC by promoting stem cell identity and growth. LIN28B is normally expressed in the intestinal epithelial crypt where cell division occurs. LIN28B represses the maturation of miRNAs such as Let-7, which is restricted to villus epithelium, where post- mitotic differentiated cells are located. The spatialrestriction of LIN28B and Let-7 expression in the intestinal epithelium is likely crucial for maintaining sufficient but limited compartments of differentiation and proliferation. C-MYC is also restricted to the crypt epithelium and is required for epithelial proliferation and growth. W have evidence to support a Let-7-independent function of LIN28B entailing intimate cooperation with c-MYC.
The Specific Aims of this proposal to test the hypothesis are the followin: 1) We will explore the functional relationship between LIN28B and c-MYC, in vitro. 2) We will assess how LIN28B cooperates with c-MYC through in vivo studies of Lin28b in the intestinal epithelium. 3) We will examine the potential of LIN28B to modulate the intestinal stem cell compartment. LIN28B function may be relevant to ISC homeostasis and epithelial proliferation. Determining how LIN28B functions in the intestinal crypt will likely provide an important link among the cellular mechanisms governing epithelial proliferation, differentiation, and/or mucosal regeneration.

Public Health Relevance

This project will explore the regulation of cell growth in the lining of the intestine in stem cells and other dividing cells. Stem cells are required to constanly replenish cells of the intestinal lining throughout the entire life of an individual. This study wll provide key insights into how intestinal cell growth is maintained; controlled; and perturbed in disease states.

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 #
7K01DK093885-04
Application #
8974891
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Podskalny, Judith M,
Project Start
2012-08-15
Project End
2017-04-30
Budget Start
2014-08-28
Budget End
2015-04-30
Support Year
4
Fiscal Year
2014
Total Cost
$110,225
Indirect Cost
$8,165
Name
Washington University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Strubberg, Ashlee M; Veronese Paniagua, Daniel A; Zhao, Tingting et al. (2018) The Zinc Finger Transcription Factor PLAGL2 Enhances Stem Cell Fate and Activates Expression of ASCL2 in Intestinal Epithelial Cells. Stem Cell Reports 11:410-424
Chatterji, Priya; Hamilton, Kathryn E; Liang, Shun et al. (2018) The LIN28B-IMP1 post-transcriptional regulon has opposing effects on oncogenic signaling in the intestine. Genes Dev 32:1020-1034
Mizuno, Rei; Chatterji, Priya; Andres, Sarah et al. (2018) Differential Regulation of LET-7 by LIN28B Isoform-Specific Functions. Mol Cancer Res 16:403-416
Wen, Yahong; Liao, Grace; Pritchard, Thomas et al. (2017) A stable but reversible integrated surrogate reporter for assaying CRISPR/Cas9-stimulated homology-directed repair. J Biol Chem 292:6148-6162
Lo, Hei-Yong G; Jin, Ramon U; Sibbel, Greg et al. (2017) A single transcription factor is sufficient to induce and maintain secretory cell architecture. Genes Dev 31:154-171
Strubberg, Ashlee M; Madison, Blair B (2017) MicroRNAs in the etiology of colorectal cancer: pathways and clinical implications. Dis Model Mech 10:197-214
Madison, Blair B (2016) Srebp2: A master regulator of sterol and fatty acid synthesis. J Lipid Res 57:333-5
Liu, Qi; Zhong, Xue; Madison, Blair B et al. (2015) Assessing Computational Steps for CLIP-Seq Data Analysis. Biomed Res Int 2015:196082
Madison, Blair B; Jeganathan, Arjun N; Mizuno, Rei et al. (2015) Let-7 Represses Carcinogenesis and a Stem Cell Phenotype in the Intestine via Regulation of Hmga2. PLoS Genet 11:e1005408
Schnepp, Robert W; Khurana, Priya; Attiyeh, Edward F et al. (2015) A LIN28B-RAN-AURKA Signaling Network Promotes Neuroblastoma Tumorigenesis. Cancer Cell 28:599-609

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