The Role of Zbtb1 in Normal and Clonal Hematopoiesis - Project Summary Clonal hematopoiesis (CH) a premalignant condition affects 20% of people above age 60, increases risk for developing blood cancers like Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), and cardiovascular disease. CH-mutant clones originate in somatically-mutated hematopoietic stem cells (HSCs), with 80% of mutations occurring in epigenetic regulators, predominantly, DNMT3A. However, the molecular mechanisms that support clonal fitness remain incompletely understood. Since CH emerges with age, we reasoned that age-related changes in HSC regulation might create selective vulnerabilities that CH clones exploit for competitive advantage. Employing multiome single-cell sequencing, we recently identified zinc finger and BTB domain containing 1 (Zbtb1) as an essential transcription factor for HSC function during hematopoietic regeneration. In our preliminary analysis, while aged HSCs exhibit decreased Zbtb1 expression, DNMT3A- mutant HSCs exhibit increased Zbtb1 with hypomethylation at the Zbtb1 locus, suggesting epigenetic dysregulation drives aberrant expression. We further observed that Zbtb1 loss eliminates clonal advantage of DNMT3A-mutant HSCs. Finally, we identified direct ZBTB1 binding to the promoters of metabolic regulators, Got2 and Impdh2, as potential downstream mediators of ZBTB1 function in HSCs, and as targets in DNMT3A- mutant CH. Therefore, we hypothesize that epigenetic derepression of ZBTB1 drives clonal advantage in DNMT3A-mutant HSCs through transcriptional reprogramming of downstream targets regulating metabolic and other cellular processes essential for clonal fitness. This career development program will address two specific aims: (1) Determine the role of ZBTB1 in normal hematopoiesis and DNMT3A-mutated CH, (2) Define the epigenomic and metabolic functions of ZBTB1 in normal and DNMT3A-mutant HSCs. During the award period, the candidate, Dr. Harold Elias, MD, will conduct research at Memorial Sloan Kettering Cancer Center under the mentorship of Dr. Michael Kharas, an expert in stem cell RNA regulation, and co-mentor Dr. Marcel van den Brink, a leader in translational hematology. Both mentors have outstanding records guiding trainees to independence, complemented by advisors with expertise in epigenetics, metabolism, computational biology, and CH. He will build on his HSC biology foundation to develop critical skills for independence as an NIH-funded laboratory-based physician-scientist. His training will focus on four key areas: advanced epigenetic and metabolomics analysis, in vivo genetic screening techniques, and prime-editing optimization for in vivo CH modeling in primary human HSPCs. This comprehensive training will enable him to develop clinically relevant disease models and enhance his computational expertise in sequencing-based approaches, to generate preclinical validation data. Completion of this project will provide the candidate with the training and mentorship required to establish his academic career as an independent laboratory-based physician-scientist whose mechanistic discoveries will provide the foundation for therapeutic strategies targeting CH and its complications.
