INDUCTION OF HEMOGENIC REPROGRAMMING IN HUMAN FIBROBLASTS
Author(s): ,
Andreia Gomes
Affiliations:
University of Coimbra,Coimbra,Portugal;Department of Developmental and Regenerative Biology,Icahn School of Medicine at Mount Sinai,New York,United States
,
Carlos-Filipe Pereira
Affiliations:
Parque Tecnologico de Cantanhede, Nucleo 4, Lote 8,CNC UC-Biotech,Cantanhede,Portugal
,
Betty Chang
Affiliations:
Department of Developmental and Regenerative Biology,Icahn School of Medicine at Mount Sinai,New York,United States;University of Coimbra,Coimbra,Portugal
,
Ilia Kurochkin
Affiliations:
Skolkovo Institute of Science and Technology,Moscow,Russian Federation
,
Michael Daniel
Affiliations:
Department of Developmental and Regenerative Biology,Icahn School of Medicine at Mount Sinai,New York,United States
,
Kenneth Law
Affiliations:
Division of Infectious Disease, Department of Medicine, Immunology Institute,Icahn School of Medicine at Mount Sinai,New York,United States
,
Namita Satija
Affiliations:
Division of Infectious Disease, Department of Medicine, Immunology Institute,Icahn School of Medicine at Mount Sinai,New York,United States
,
Alexander Lachmann
Affiliations:
Department of Pharmacology and Systems Therapeutics,Icahn School of Medicine at Mount Sinai,New York,United States
,
Zichen Wang
Affiliations:
Department of Pharmacology and Systems Therapeutics,CNC UC-Biotech,New York,United States
,
Lino Ferreira
Affiliations:
UC-Biotech,University of Coimbra,Coimbra,Portugal
,
Avi Ma'ayan
Affiliations:
Department of Pharmacology and Systems Therapeutics,Icahn School of Medicine at Mount Sinai,New York,United States
,
Benjamin Chen
Affiliations:
Division of Infectious Disease, Department of Medicine, Immunology Institute,Icahn School of Medicine at Mount Sinai,New York,United States
,
Dmitri Papatsenko
Affiliations:
Skolkovo Institute of Science and Technology,Moscow,Russian Federation
,
Ihor R. Lemischka
Affiliations:
Department of Developmental and Regenerative Biology,Icahn School of Medicine at Mount Sinai,New York,United States
Kateri A. Moore
Affiliations:
Parque Tecnologico de Cantanhede, Nucleo 4, Lote 8,Icahn School of Medicine at Mount Sinai,New York,United States
(Abstract release date: Jun 8, 2017) EHA Learning Center. Gomes A. Jun 25, 2017; 183930
Andreia Gomes
Andreia Gomes

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Abstract: LB2605

Type: Late Breaking Oral Session

Presentation during EHA22: On Sunday, June 25, 2017 from 12:30 – 12:45

Location: Hall A

Background
Hematopoietic stem cells (HSCs) are multipotent stem cells capable of sustaining all mature blood cells throughout life. During development, HSCs arise directly from specialized endothelial cells called hemogenic endothelial (HE) cells within the developing aorta-gonad-mesonephros (AGM) region, in a process termed endothelial-to-hematopoietic transition (EHT). However, despite extensive studies in various animal models, the genetic program driving human HSC emergence remains largely unknown.We have previously reported the generation of hemogenic precursor cells from mouse fibroblasts with the expression of the transcription factors (TFs) Gata2, cFos, Gfi1b and Etv6. These TFs induce a dynamic, multi-stage hemogenic process that progresses through an endothelial-like intermediate, recapitulating developmental hematopoiesis in vitro.

Aims
Here, to better understand the molecular events underlying human HE cell specification we expressed hemogenic TFs in human fibroblasts and mapped the TF binding sites at initial stages of reprogramming.

Methods
To determine the transcription factors binding sites we used Chromatin Immunoprecipitation coupled with sequencing (ChIP-seq).

Results
We demonstrate that human fibroblasts can be reprogrammed into hemogenic cells by the expression of GATA2, GFI1B and FOS. Induced cells express CD34 and CD49f and display dynamic endothelial to hematopoietic transcription programs. In addition, reprogrammed fibroblasts repopulate immunodeficient NSG mice and generate hematopoietic progeny of multiple lineages, including T-cells and myeloid cells. Mechanistically, GATA2 display dominant and independent targeting activity during the early phases of reprogramming while GFI1B depends on GATA2 to bind most of its targets. Interestingly, GATA2 and GFI1B interact and co-occupy a cohort of target sites engaging sites preferentially with AP-1 motifs, including the RUNX1 locus. This cooperative binding is reflected by the engagement of open enhancers and promoters marked by H3K4me3, H3K4me1 and H3K27ac in the fibroblast genome that initiates the silencing of fibroblast genes while activating the hemogenic program. 

Conclusion
Together, these findings uncover a collaborative TF interaction that specify a human hemogenic program and EHT. These findings shed light on the processes controlling human HSC specification and provide means to generate human reprogrammed HSCs at high efficiency for transplantation.

Session topic: 23. Hematopoiesis, stem cells and microenvironment

Keyword(s): Hemangioblast, Hematopoietic cell transplantation, Hematopoietic stem and progenitor cells, Transcription factor

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