Project Details
Projekt
Comparative functional characterization of distinct CH mutations recurrent in cardiovascular disease and myeloid malignancies (Project B1)
Subject Area
Hematology, Oncology
Cardiology, Angiology
Cardiology, Angiology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 515629962
Clonal hematopoiesis (CH) is an almost ubiquitous phenomenon with age and has gathered considerable interest because its extent is associated with cardiovascular morbidity and mortality, as well as with myeloid neoplasms (MN). Sequencing efforts revealed that many CH-associated mutations occur in genes that were previously known to drive clonal evolution in MN, which led to the hypothesis that CH may constitute a preleukemic state, driven by the CH-associated mutations. We analyzed publicly available and our own clinical databases of CH individuals, and found, that although different mutations in the same gene can be found in CH and in MN, many of these mutations occur exclusively in CH, but cannot be found with increased frequency in MN. This is especially true for missense mutations of the most frequent CH genes, the epigenetic modifiers DNMT3A and TET2. The central hypothesis of this proposal is therefore that different mutations in the same CH-associated gene may or may not be leukemia drivers, which is reflected in their occurrence or non-occurrence in MN. Comparative analysis of gene variants that are found in MN versus those variants that are not should then allow to understand their function as leukemia drivers. To test this hypothesis, we here will introduce both types of mutations endogenously into DNMT3A and TET2 by CRISPR-mediated cytosine base editing (CBE) and characterize their effects alone and in the context of cooperating oncogenes. Beyond their biochemical characterization, we will analyze their consequences on gene regulatory networks, their effects on clonal dominance, on hematopoietic differentiation, and on their leukemogenic potential. In addition, the CH gene variants will also be assessed for their effects on proinflammatory macrophage function in appropriate in vitro and in vivo models in close collaboration within the consortium, where these models are available. This project will result in better understanding of the role of DNMT3A and TET2 as leukemia driver genes beyond their effects on clonal dominance. Additionally, this will significantly contribute to the increasingly appreciated notice that the outcome of CH-affected individuals cannot only be predicted by the size of the affected clone, but also by the affected gene, or, as in our case, by the specific variant of a given gene.
DFG Programme
Research Units
