Project description:A gradual restriction in lineage potential of multipotent stem/progenitor cells is a hallmark of adult hematopoiesis, but the underlying molecular events governing these processes remain incompletely understood. Here, we identified robust expression of the leukemia-associated transcription factor hepatic leukemia factor (Hlf) in normal multipotent hematopoietic progenitors, which was rapidly downregulated upon differentiation. Interference with its normal downregulation revealed Hlf as a strong negative regulator of lymphoid development, while remaining compatible with myeloid fates. Reciprocally, we observed rapid lymphoid commitment upon reduced Hlf activity. The arising phenotypes resulted from Hlf binding to active enhancers of myeloid-competent cells, transcriptional induction of myeloid, and ablation of lymphoid gene programs, with Hlf induction of nuclear factor I C (Nfic) as a functionally relevant target gene. Thereby, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis.
Project description:Blood cell formation is a tightly regulated process initiated from a rare population of multipotent hematopoietic stem cells. Subsequent differentiation proceeds in a hierarchical manner with the generation of intermediate progenitor cells, in which alternative lineage potentials become gradually restricted. A deeper understanding of these events is crucial not only to understand normal blood cell formation, but also for leukemia, where a defining feature is inappropriate differentiation. Here, we identified Hepatic Leukemia Factor (Hlf) as being highly and selectively expressed in primitive multipotent hematopoietic stem and progenitors. We demonstrate that Hlf is a strong negative regulator of B-, NK- and T cell development and instructs multipotent progenitors to adopt a myeloid fate in a cell autonomous manner; phenotypes underwritten by the induction of myeloid affiliated transcriptional programs, the concomitant ablation of lymphoid gene programs and a genome-wide binding spectra that involved active enhancers of myeloid-competent cells. Collectively, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis. Gene expression profiling of control or Hlf/Hlf lentivirus infected GMLPs (2 replicates per group) and Hlf inducible GMLPs maintained for 4 days on OP9 stroma in the presence or absence of doxycycline (2 replicates per group)
Project description:Hematopoiesis commences with a gradual restriction in lineage potential of multipotent stem/progenitor cells, but the underlying molecular events of this remain incompletely understood. We here identify robust expression of the transcription factor Hepatic Leukemia Factor (Hlf) in multipotent hematopoietic progenitors, which is rapidly lost with differentiation. Prolonged Hlf expression reveals it as a strong negative regulator of lymphoid development and results in a pronounced and reversible differentiation block in the B-cell lineage, while remaining compatible with myeloid fates. Reciprocally, we observe rapid lymphoid commitment upon eduction of Hlf activity. These phenotypes result from Hlf-binding to active enhancers of myeloid-competent cells, induction of myeloid-affiliated transcription and ablation of lymphoid gene programs, with Hlf induction of Nuclear Factor I C (Nfic) as a functionally relevant target gene. Collectively, we establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage restricted progeny.
Project description:A gradual restriction in lineage potential of multipotent stem/progenitor cells is a hallmark of adult hematopoiesis, but the underlying molecular events governing these processes remain incompletely understood. Here, we identified robust expression of the leukemia-associated transcription factor Hepatic Leukemia Factor (Hlf) in normal multipotent hematopoietic progenitors, which was rapidly downregulated upon differentiation. Interference with its’ normal downregulation revealed Hlf as a strong negative regulator of lymphoid development, while remaining compatible with myeloid fates. Reciprocally, we observed rapid lymphoid commitment upon reduced Hlf activity. The arising phenotypes resulted from Hlf-binding to active enhancers of myeloid-competent cells, transcriptional induction of myeloid and ablation of lymphoid gene programs, with Hlf induction of Nuclear Factor I C (Nfic) as a functionally relevant target gene. Thereby, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis.
Project description:Blood cell formation is a tightly regulated process initiated from a rare population of multipotent hematopoietic stem cells. Subsequent differentiation proceeds in a hierarchical manner with the generation of intermediate progenitor cells, in which alternative lineage potentials become gradually restricted. A deeper understanding of these events is crucial not only to understand normal blood cell formation, but also for leukemia, where a defining feature is inappropriate differentiation. Here, we identified Hepatic Leukemia Factor (Hlf) as being highly and selectively expressed in primitive multipotent hematopoietic stem and progenitors. We demonstrate that Hlf is a strong negative regulator of B-, NK- and T cell development and instructs multipotent progenitors to adopt a myeloid fate in a cell autonomous manner; phenotypes underwritten by the induction of myeloid affiliated transcriptional programs, the concomitant ablation of lymphoid gene programs and genome-wide binding spectra that involved active enhancers of myeloid-competent cells. Collectively, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis.