This K08 proposal has been developed to facilitate my career development through coursework, training in professional development, guidance from my mentor as well as my advisory committee, and research training. My background in genomics and cancer susceptibility has led me to pursue additional training in hematopoietic stem cell biology in order to round out my skills in translational research and achieve my long-term goal of becoming an independent investigator and leader in the area of hematopoiesis and leukemia susceptibility. My short-term goal is therefore to pursue additional research training in Dr. John Chute's lab with the aim of increasing understanding of the role of the bone marrow (BM) niche in the hematopoietic stem cell (HSC) functional decline with aging, injury, and leukemogenesis. As HSCs age, they display distinct abnormalities such as skewing toward myeloid differentiation, decreased repopulation ability, and cancer predisposition. Clinically, this corresponds with the increasing incidence of myelodysplasia, myeloproliferative diseases, acute leukemia, as well as adaptive immune system defects. Our lab has demonstrated that BM endothelial cells (ECs) produce epidermal growth factor (EGF) which is capable of markedly accelerating HSC regeneration and overall hematopoietic reconstitution following acute radiation injury. Interestingly, high dose irradiation produced a phenotype of accelerated aging in the hematopoietic system. Therefore, I hypothesize that augmentation of the HSC vascular niche paracrine mechanisms, such as the EGF signaling pathway, can rescue this declining function.
The specific aims and approaches are to (1) determine whether EGF treatment is sufficient to reverse HSC aging, using pharmacologic approaches, (2) determine whether cell-specific deletion of EGFR accelerates HSC and immune system aging, using a mouse model which results in a loss-of-function of EGFR on bone marrow stem and progenitor cells, and (3) determine the mechanisms through which EGF reverses HSC aging by testing the effect of EGF on HSC senescence, survival, cell cycle status, and the Ras/MEK/ERK pathway. This is a high-impact, translational proposal that applies state-of-the-art techniques and unique mouse models to characterize the role and mechanism by which EGF rejuvenates aging HSCs. This will provide the basis of a novel role for EGF and has significant translational potential to ameliorate the adverse effects of HSC aging and injury after chemotherapy, radiation therapy, and bone marrow transplantation.

Public Health Relevance

Aging is a universal human condition that is accompanied by progressive decline in organ function. As hematopoietic stem cells age, they display distinct abnormalities such as skewing toward myeloid differentiation, decreased repopulation ability, and cancer predisposition, which clinically corresponds to an increasing incidence of myelodysplasia, myeloproliferative diseases, acute leukemia, as well as adaptive immune system defects. This proposal will investigate the role for epidermal growth factor in rejuvenating hematopoietic stem cells and has significant translational potential to ameliorate the adverse effects of stem cell aging, injury after chemotherapy, radiation therapy, and bone marrow transplantation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08HL138305-02
Application #
9547930
Study Section
NHLBI Mentored Clinical and Basic Science Review Committee (MCBS)
Program Officer
Chang, Henry
Project Start
2017-09-01
Project End
2022-07-31
Budget Start
2018-08-01
Budget End
2019-07-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Pediatrics
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Chang, Vivian Y; Termini, Christina M; Chute, John P (2017) Young endothelial cells revive aging blood. J Clin Invest 127:3921-3922