GATA2 variants retain enhancer activity, alter differentiation, and may link inflammation to hematologic malignancy risk.
By retaining a selective enhancer-dependent transcriptional program despite impaired function, pathogenic GATA2 variants may distort hematopoietic differentiation and prime inflammatory signaling pathways, offering a potential mechanistic link between germline predisposition and the development of hematologic malignancies such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML).1-3
Emerging data further suggest that GATA2 normally constrains inflammatory signaling by decommissioning specific enhancers, a process that is disrupted when GATA2 function is reduced.1
“Our group is very interested in cancer predisposition syndromes. When an individual has germline genetic variation, that creates a greater probability of developing a blood cancer,” Emery H. Bresnick, PhD, said in an interview with OncLive®.
Bresnick is the Gary Felsenfeld Professor of Cell and Regenerative Biology, the Lowell and Gwendolyn Smythe Endowed Professor, and director of the University of Wisconsin (UW)-Madison Blood Cancer Research Program at the UW School of Medicine and Public Health.
In a preclinical study, Bresnick and colleagues determined that GATA2 variants retain enhancer activity, skew differentiation, and may link inflammation to leukemia risk in predisposed patients.1,2 Complementary mechanistic work demonstrates that GATA2 represses inflammatory cytokine receptor genes, including Il6ST and Il6RA, by maintaining their enhancers in a dormant state, limiting downstream signaling such as IL-6– and IL-27–mediated pathways.1
GATA2 is a master transcriptional regulator of hematopoietic stem and progenitor cells. Germline variants in GATA2 have been associated with GATA2 deficiency syndrome, a condition characterized by bone marrow failure, immunodeficiency, and a predisposition to MDS and AML.
Unlike canonical oncogenic mutations that confer clear gain or loss effects, GATA2 variants often produce partial or context-dependent activity, complicating efforts to define their pathogenicity and clinical significance.
“Those prior papers demonstrated that when you have a genetic variant that we call pathogenic, it creates the predisposition,” Bresnick explained. “We call those cells GATA2-deficient cells, because they don’t have enough normal GATA2 function.”
However, further research is needed to fully understand the downstream consequences of this deficiency, including how GATA2 loss affects chromatin accessibility and inflammatory signaling networks.
Using a genetic rescue system in GATA2-deficient progenitors, Bresnick and colleagues reintroduced either GATA2 wild-type or disease-associated variants to compare transcriptional and differentiation outputs, using approaches such as RNA sequencing and chromatin profiling to define genome-wide regulatory effects.2
“We innovated an assay called a genetic rescue assay where we reintroduced normal [GATA2] or a human clinical variant, and then we could compare the activity,” Bresnick said.
The analysis demonstrated that pathogenic variants do not fully abrogate GATA2 function. Rather, they retain the ability to regulate a subset of target genes and fail to activate others. At the molecular level, both GATA2 wild-type and variants were associated with activation of an obligate enhancer driving C/EBPε expression, promoting granulopoiesis.
In parallel, newer data indicate that GATA2 represses distinct enhancer elements at inflammatory receptor loci.1 When GATA2 levels are reduced, these enhancers become accessible, are occupied by transcription factors such as PU.1, and drive expression of cytokine receptor genes, including Il6ST and Il6AR. This shift increases signaling capacity through pathways such as JAK/STAT, particularly STAT3 activation.
Beyond differentiation, research has demonstrated how GATA2 deficiency alters inflammatory gene regulation. Prior work had shown that GATA2-deficient cells exhibit elevated expression of inflammatory signaling genes, but the underlying mechanism was unclear.2
“The crux of the problem was, how does lowering GATA2 elevate inflammatory signaling genes?” Bresnick asked.
Investigators found that GATA2 normally represses specific transcriptional enhancers that control inflammatory genes. When GATA2 levels are reduced, these enhancers undergo a chromatin transition that increases accessibility and transcription factor occupancy, thereby increasing gene expression and cytokine responsiveness.
“In a normal cell, GATA2 is limiting the activity of the enhancer sequences, but when you have a GATA2-deficient cell, the enhancers become active, and then they turn on the genes,” Bresnick explained.
This enhancer activation is partially mediated by an altered balance with other transcription factors, such as PU.1, which can drive inflammatory gene expression in the absence of sufficient GATA2-mediated repression. Functionally, this includes heightened IL-6 and IL-27 signaling, both of which have been implicated in hematopoietic dysfunction and leukemic progression.1
These data contribute to the understanding of the heterogeneous clinical presentation of GATA2 deficiency syndrome. Rather than a uniform loss of hematopoietic function, patients exhibit lineage-specific abnormalities driven by selective retention of transcriptional programs and dysregulated enhancer activity.2
The data also support a model in which inflammatory signaling may cooperate with germline GATA2 variants to promote leukemogenesis. Enhanced cytokine receptor expression and downstream signaling may render progenitor cells hypersensitive to inflammatory cues, a state linked to disease progression in multiple hematologic contexts.
“The genetic variant creates a predisposition, but is insufficient for pathogenesis,” Bresnick noted. “Our underlying hypothesis is that if you have blood cancer predisposition genes plus dysregulated inflammation, the inflammation might be a trigger.”
This has potential translational relevance. Therapeutic strategies aimed at modulating inflammatory pathways—or restoring proper enhancer repression—could, in principle, delay or prevent progression from a predisposition state to overt malignancy, although this remains to be validated.
Investigators emphasized the need for preclinical models that integrate genetic predisposition with environmental or inflammatory stimuli to better define disease triggers and test preventive strategies.
“It’s very important that we have powerful models that will allow us to study the multiple steps in the process,” Bresnick said.
These models may enable the evaluation of targeted interventions in the preleukemic setting. This concept is gaining traction as genomic screening identifies an increasing number of patients with inherited risk variants. In particular, understanding how enhancer decommissioning constrains inflammatory signaling—and how its failure contributes to disease—may reveal new intervention points.
In parallel, efforts are underway to improve the interpretation of GATA2 variants identified through clinical sequencing. Given the large number of possible missense and noncoding variants, functional assays are essential for distinguishing pathogenic alterations from benign findings.
“Many patients will learn that they have a particular genetic variant, but in many cases, we still don’t know what it means,” Bresnick said.
