Targeting ZNF410 for HbF reactivation

ABSTRACT
Hemoglobin disorders, such as sickle cell disease and β-thalassemia, comprise the most common monogenic
diseases of the world and yet, current treatments remain largely supportive and inadequate. Induction of fetal
hemoglobin (HbF) could bypass the fundamental genetic defects of adult hemoglobin that cause these
diseases. Recent gene therapy successes provide proof-of-concept that understanding the molecular control of
adult-stage HbF silencing can identify rational therapeutic targets. However, gene therapy cannot be scaled up
globally to match the scope of the clinical problem for the foreseeable future. Therefore, novel
pharmacotherapies are needed to induce HbF. The major HbF regulators BCL11A, ZBTB7A, and NuRD each
have on-target liabilities that could make therapeutic targeting challenging. Recently ZNF410 was discovered
to be a novel transcriptional repressor of HbF level during adult-stage erythropoiesis. ZNF410 has a narrow
biological action, which is to enhance the expression of CHD4. CHD4 possesses a unique array of 27
reiterated ZNF410 binding motifs at its promoter and upstream enhancer, an assemblage without comparison
in the rest of the genome. This study aims to investigate the: mechanisms whereby ZNF410 controls the
expression of CHD4 through homotypic motif clusters; requirements for ZNF410 and its orthologs throughout
development, homeostasis and hematopoiesis; and potential of targeted protein degradation of ZNF410 by
IMiD congeners as a therapeutic approach. Near-term goals are to define the role of protein-level cooperativity
and chromatin accessibility in binding to CHD4 by ZNF410 and the relationship between ZNF410 binding
events and CHD4 expression. These mechanistic studies will help identify vulnerabilities in this regulatory axis
that might be targeted therapeutically. Furthermore, the roles of ZNF410 throughout mouse development and
adulthood as well as in human hematopoiesis will be investigated. Constitutive and conditional alleles of
Zfp410 and its cognate regulatory elements at Chd4 in mice will be generated and characterized.
Requirements for ZNF410 throughout human erythropoiesis and hematopoiesis will be identified by bulk and
single cell gene expression and chromatin profiling in vitro and in vivo. Finally, tool compounds will be
generated to validate targeted protein degradation of ZNF410 by small molecules as a promising therapeutic
approach. Structural evaluation and systematic exploration of structure-activity relationships will be leveraged
to obtain instructive compounds to evaluate in ZNF410/Zfp410 sufficient and deficient cellular and animal
models the therapeutic premise that ZNF410 is a favorable therapeutic target for HbF induction in the β-
hemoglobinopathies. The long-term goal is to promote the development of drug-like small molecules that
ultimately could be used in clinical trials.

Grant Number: 5R01HL167513-03
NIH Institute/Center: NIH
Principal Investigator: Daniel Bauer