Modeling GATA2 deficiency in mice: the R396Q mutation disrupts normal hematopoiesis

GATA2 deficiency is an autosomal dominant germline disorder of immune dysfunction and bone marrow failure with a high propensity for leukemic transformation in adolescents, present in up to 7% of pediatric myelodysplastic syndrome (MDS) and 15% of advanced MDS cases. While sequencing studies have identified several secondary mutations thought to contribute to malignancy, the mechanisms of disease progression have been difficult to identify due to a lack of disease-specific experimental models. Here, we generated a murine model of one of the most common GATA2 mutations associated with leukemic progression in GATA2 deficiency, Gata2R396Q/+. While mutant mice exhibit mild defects in peripheral blood output throughout life, they display significant hematopoietic abnormalities in the bone marrow (BM), including a reduction in hematopoietic stem cell (HSC) function and intrinsic biases toward specific stem cell subsets that differ from previous models of GATA2 loss. Supporting this observation, single-cell RNA sequencing of BM hematopoietic progenitors revealed a loss of HSC stemness, myeloid-bias, and accelerated ageing phenotype. Importantly, we show that Gata2R396Q/+ exerts effects early in hematopoietic development, as mutant mice generate fewer HSCs in the aorta gonad mesonephros, and fetal liver HSCs have reduced function. This reduced pool of HSCs and aged phenotype could be potential contributors to leukemic transformation in patients, and our model provides a useful tool to study the mechanisms of malignant transformation in GATA2 deficiency.