Our lab is focused on improving the understanding of the regulation of hematopoietic stem cells. Recently we identified a critical role for the de novo DNA methyltransferase, DNMT3A, in the maintenance of normal hematopoiesis. Deletion of Dnmt3a in a murine model led to dramatically increased stem cell self-renewal and blocked differentiation. Our findings are relevant to human disease, as DNMT3A is frequently the founding genetic lesion in a variety of hematologic malignancies and is the most commonly mutated gene in age-related clonal hematopoiesis. Our studies and these findings in human diseases indicate that stem cells in which DNMT3A function is lost have a competitive advantage, allowing for aberrant clonal expansion. The parent award associated with this supplement aims to gain insight into the mechanisms by which DNMT3A mutations confer an advantage to HSCs and contribute to clonal expansion as well as to the development of MDS and leukemia in the general population. In this proposal, we aim to similarly study the mechanisms by which hematopoietic stem cells in some children with Down syndrome (DS) gain a competitive advantage, undergo clonal expansion and, in some, ultimate malignant transformation. The clonally expanded populations frequently harbor mutations of regulators of higher order chromatin structure, including mutations of DNMT3A, cohesin complex members and mutations/deletions of CTCF. This indicates many of the same mechanisms driving clonal expansion in age related clonal hematopoiesis, may be at work in children with DS. The work we propose here will build upon our ongoing work in non-DS clonal hematopoiesis and provide new insight into the underlying aberrations of clonal expansion in DS. In addition to being well within the scope of the parent NIDDK award, the work we propose here directly addresses INCLUDE Project Component 1 as it is a basic science investigation highly relevant to DS, with a high likelihood of positively impacting the health of a large percentage of children with DS. The studies we will conduct includes development of novel murine models of the clonal DS hematopoietic disorder, TAM, and epigenetic and transcriptomic profiling in these model DS hematopoietic systems, both topics of emphasis under the INCLUDE Project. Our findings could identify key targets for therapeutic intervention, paving the way for future clinical trials for children with DS. This work is also well aligned with the overarching goal of the Hematologic Disease research program of the NIDDK, which aims to improve the understanding of the basic cellular and molecular mechanisms underlying the production and function of blood cells. In summary, we aim to leverage our lab?s expertise in the study of hematopoiesis, extending our investigations of mechanisms of clonal expansion in non-DS individuals to study the clonal hematologic anomalies prevalent in children with DS.

Public Health Relevance

Blood is regenerated throughout life by specialized stem cells. Normal function of these stem cells requires action of a DNA modifying enzyme called DNMT3A, and it mutation is associated with abnormal blood production as well myelodysplastic syndrome (MDS) and leukemia development. The overall goal of this project is to understand what aspects of blood development require this enzyme and how it functions, with a view to being able to modulate these properties for potential therapeutic benefit.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
3R01DK092883-07S1
Application #
9780779
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Bishop, Terry Rogers
Project Start
2013-09-01
Project End
2021-05-31
Budget Start
2018-09-15
Budget End
2019-05-31
Support Year
7
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Pediatrics
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
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Hsu, Joanne I; Dayaram, Tajhal; Tovy, Ayala et al. (2018) PPM1D Mutations Drive Clonal Hematopoiesis in Response to Cytotoxic Chemotherapy. Cell Stem Cell 23:700-713.e6
Brunetti, Lorenzo; Gundry, Michael C; Sorcini, Daniele et al. (2018) Mutant NPM1 Maintains the Leukemic State through HOX Expression. Cancer Cell 34:499-512.e9
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Jeong, Mira; Guzman, Anna G; Goodell, Margaret A (2017) Genome-Wide Analysis of DNA Methylation in Hematopoietic Cells: DNA Methylation Analysis by WGBS. Methods Mol Biol 1633:137-149
Huang, Yung-Hsin; Su, Jianzhong; Lei, Yong et al. (2017) DNA epigenome editing using CRISPR-Cas SunTag-directed DNMT3A. Genome Biol 18:176
Lei, Yong; Zhang, Xiaotian; Su, Jianzhong et al. (2017) Targeted DNA methylation in vivo using an engineered dCas9-MQ1 fusion protein. Nat Commun 8:16026
Brunetti, Lorenzo; Gundry, Michael C; Goodell, Margaret A (2017) DNMT3A in Leukemia. Cold Spring Harb Perspect Med 7:
Eckstein, Olive S; Wang, Linghua; Punia, Jyotinder N et al. (2016) Mixed-phenotype acute leukemia (MPAL) exhibits frequent mutations in DNMT3A and activated signaling genes. Exp Hematol 44:740-4

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