Our long-term research goals are to understand the mechanisms that regulate stem cell fate decisions. This proposal focuses on epigenetic regulation of cell identity. Open chromatin has been proposed as one of the hallmarks of stem cells, explaining their multilineage potential. Using the hematopoietic stem cell (HSC) system as a model of adult stem cell differentiation, we propose to test whether HSC have a more open and dynamic chromatin structure than lineage committed progenitors and mature cells. In addition, we will test the functional consequences of chromatin condensation, and manipulate heterochromatin formation during HSC differentiation. Importantly, we have discovered that highly purified hematopoietic stem and progenitor cells have a more nuclease-sensitive chromatin structure compared to mature cells. This nuclease sensitivity correlates with linage potential and with differential three-dimensional chromatin organization. Here, we will investigate the mechanisms behind these differences. We will analyze the global molecular changes of DNA and histone proteins by sensitive assays capable of detecting differences in small numbers of cells. We will test how HSC differentiation and fate decisions change upon inhibition of chromatin modifying enzymes using a combination of complementary molecular, cellular, and functional assays in vitro and in vivo. Lastly, we will perform comparative chromatin analyses between HSC and leukemic stem cells and assess the contribution of chromatin modifications in leukemic transformation. We anticipate that these results will provide novel insights to the dynamics of chromatin structure and organization during stem cell differentiation and transformation, with important implications for both normal hematopoietic development and leukemogenesis.

Public Health Relevance

This proposal will investigate mechanisms regulating the function of blood-forming stem cells. The findings will be important for understanding, further investigating, and using hematopoietic cells to improve the treatment of cancer and disorders of the blood and immune system.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL115158-01A1
Application #
8578535
Study Section
Molecular and Cellular Hematology (MCH)
Program Officer
Thomas, John
Project Start
2013-08-01
Project End
2018-05-31
Budget Start
2013-08-01
Budget End
2014-05-31
Support Year
1
Fiscal Year
2013
Total Cost
$377,719
Indirect Cost
$130,102
Name
University of California Santa Cruz
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
125084723
City
Santa Cruz
State
CA
Country
United States
Zip Code
95064