This item is under embargo and not available online per the author's request. For access information, please visit http://libanswers.wustl.edu/faq/5640.

Date of Award

Summer 8-15-2018

Author's School

Graduate School of Arts and Sciences

Author's Department

Biology & Biomedical Sciences (Human & Statistical Genetics)

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

KDM6B (JMJD3) is one of two known epigenetic modifiers responsible for the removal of the repressive histone mark, histone-3 lysine-27 trimethylation (H3K27me3), and has been shown to play a role in development, differentiation, and inflammatory stress response. Unlike the other H3K27me3 demethylase, UTX (KDM6A), which is frequently mutated in hematopoietic malignancies, KDM6B is upregulated in a myriad of blood disorders. This suggests that it may have important functions in the pathogenesis of hematopoietic cancers. Here, we examined the role of Kdm6b in hematopoietic stem cell (HSC) fate decisions under normal and malignant conditions to evaluate its potential as a therapeutic target. Loss of Kdm6b leads to a significant reduction in phenotypic and functional HSCs in adult mice, which increases with increased age. Loss of Kdm6b results in the inability to maintain the HSC population post-transplantation in a dose-dependent manner. In addition, Kdm6b is necessary for HSC self-renewal in response to inflammatory, genotoxic and oncogenic stress. Kdm6b HSCs have a stress response gene expression signature which overlaps significantly with immediate early response genes, genes associated with aged HSCs and genes involved in quiescence of HSCs. When stimulated with an inflammatory or proliferative agent, Kdm6bФeficient HSCs are not able to efficiently resolve gene expression programs, leading to delayed cell cycle entry and a self-renewal block, forcing them to differentiate once they commit to divide. Thus, Kdm6b is necessary for self-renewal of normal and leukemic stem cells, and KDM6B inhibition combined with proliferative agents may force differentiation and eventual depletion of leukemic stem cells in patients.

Language

English (en)

Chair and Committee

Grant A. Challen

Committee Members

Todd E. Druley, Daniel C. Link, Jeffrey A. Magee, Laura G. Schuettpelz,

Comments

Permanent URL: 2019-05-29

Available for download on Wednesday, May 29, 2019

Share

COinS