PF346 ZEBRAFISH AS A NOVEL MODEL TO STUDY GATA2 HAPLOINSUFFICIENCY SYNDROMES

Abstract

Background:Patients with GATA2 mutations have up to 80% chance to develop a myeloid malignancy. MonoMAC and Emberger syndromes are GATA2 deficiency syndromes and are characterized by monocytopenia, B, NK cell lymphopenia and a predisposition to acute myeloid leukemia (AML). Although the disease initiating mutation is known, it is unclear how these patients develop hematological malignancies.Aims:In our research we use both mouse and zebrafish models of Gata2 haploinsufficiency to describe their phenotypes and study the mechanisms of malignant transformation.Methods:In mice we analyzed the transcriptome and functionality of LSK SLAM in Gata2 mutants. In zebrafish, two orthologues of Gata2 exist: gata2a and gata2b of which gata2b was shown to be predominantly expressed in hematopoietic cells. We used CRISPR‐Cas9 to generate zebrafish gata2b mutants and evaluate their phenotype using flow cytometry, RNAseq, histology and in situ hybridization. Using single‐cell RNA sequencing we aim to identify early onset markers of dysplasia and unveil the mechanism of malignant transformation.Results:Gata2 heterozygous mutant mice survive into adulthood without developing signs of alterations in the myeloid lineage. Phenotypic HSCs of these mutant adult mice have unchanged Gata2 expression but are lower in frequency, more proliferative and transcriptionally more committed to differentiation compared to WT. Additionally, they display increased DNA damage indicating these HSCs experience proliferative stress. gata2b +/− zebrafish show reduced myeloid differentiation and the kidney marrow smears of this aged fish show dysplastic myeloid cells.Summary/Conclusion:Our mouse model doesn’t incur a malignancy even though it acquires an HSCs phenotype. Our zebrafish model develops a dysplastic kidney marrow and recapitulates characteristics of the GATA2 deficiency syndromes. Both models can give new insights into the physiopathology of these diseases.