Project description:The vasculature is an essential organ for the delivery of blood and oxygen to all tissues of the body and thus relevant to the treatment of ischemic diseases, injury-induced regeneration, and solid tumor growth. Therefore, the definition of pioneer factors and regulatory pathways that govern the specification and differentiation of endothelial progenitors will serve as a platform for targeted therapies to promote cardiovascular regeneration and treatment of solid organ tumors. Previously, we demonstrated that ETV2 was an essential transcription factor for the development of cardiac, endothelial and hematopoietic lineages. Here, we report that ETV2 functions as a novel pioneer factor that relaxes closed chromatin and regulates endothelial development. By comparing engineered embryonic stem cell differentiation and reprogramming models with single cell RNA-seq, ATAC-seq and ChIP-seq techniques, we demonstrated that ETV2 was able to bind nucleosomal DNA and function as a pioneer factor independent of the cellular context. We determined that ETV2 executes a pioneering role by recruiting BRG1 to remodel chromatin around endothelial genes and help maintain an open configuration. ETV2 chromatin binding also resulted in increased H3K27ac deposition. Collectively, these results will serve as a platform for the development of therapeutic initiatives directed towards cardiovascular and oncological diseases.
Project description:The vasculature is an essential organ for the delivery of blood and oxygen to all tissues of the body and thus relevant to the treatment of ischemic diseases, injury-induced regeneration, and solid tumor growth. Therefore, the definition of pioneer factors and regulatory pathways that govern the specification and differentiation of endothelial progenitors will serve as a platform for targeted therapies to promote cardiovascular regeneration and treatment of solid organ tumors. Previously, we demonstrated that ETV2 was an essential transcription factor for the development of cardiac, endothelial and hematopoietic lineages. Here, we report that ETV2 functions as a novel pioneer factor that relaxes closed chromatin and regulates endothelial development. By comparing engineered embryonic stem cell differentiation and reprogramming models with single cell RNA-seq, ATAC-seq and ChIP-seq techniques, we demonstrated that ETV2 was able to bind nucleosomal DNA and function as a pioneer factor independent of the cellular context. We determined that ETV2 executes a pioneering role by recruiting BRG1 to remodel chromatin around endothelial genes and help maintain an open configuration. ETV2 chromatin binding also resulted in increased H3K27ac deposition. Collectively, these results will serve as a platform for the development of therapeutic initiatives directed towards cardiovascular and oncological diseases.
Project description:The vasculature is an essential organ for the delivery of blood and oxygen to all tissues of the body and thus relevant to the treatment of ischemic diseases, injury-induced regeneration, and solid tumor growth. Therefore, the definition of pioneer factors and regulatory pathways that govern the specification and differentiation of endothelial progenitors will serve as a platform for targeted therapies to promote cardiovascular regeneration and treatment of solid organ tumors. Previously, we demonstrated that ETV2 was an essential transcription factor for the development of cardiac, endothelial and hematopoietic lineages. Here, we report that ETV2 functions as a novel pioneer factor that relaxes closed chromatin and regulates endothelial development. By comparing engineered embryonic stem cell differentiation and reprogramming models with single cell RNA-seq, ATAC-seq and ChIP-seq techniques, we demonstrated that ETV2 was able to bind nucleosomal DNA and function as a pioneer factor independent of the cellular context. We determined that ETV2 executes a pioneering role by recruiting BRG1 to remodel chromatin around endothelial genes and help maintain an open configuration. ETV2 chromatin binding also resulted in increased H3K27ac deposition. Collectively, these results will serve as a platform for the development of therapeutic initiatives directed towards cardiovascular and oncological diseases.
Project description:We discover that ER71/ETV2 initiates hemangiogenic program by activating blood and endothelial cell lineage specifying genes while enhancing FLK1 expression and expanding hemangioblast population. Furthermore, ER71/ETV2 establishes an ETS hierarchy by directly activating Ets genes in hematopoietic and endothelial cell lineage development. As such, ER71/ETV2-initiated blood and endothelial cell program is maintained by ER71/ETV2 downstream ETS factors through an ETS switching mechanism. ChIP-seq analysis of ER71 in differentiated embryonic stem cells
Project description:A comprehensive understanding of a lineage map and molecular mechanisms underlying lineage specification is fundamental to development. To this end, ETS transcription factor Etv2 functions as the master regulator of hematopoietic and endothelial cell formation. As such, Etv2 regulated hemangiogenesis provides an excellent model for assessing cell lineage specification. Herein, we generated several reporter embryonic stem (ES) cell lines to map developmental route pertaining to hemangiogenesis. We performed transcriptome analysis and high throughput CRISPR screening to further delineate molecular mechanisms regulating hemangiogenic lineage specification. We show a distinct lineage map of hemangiogenesis, in which hemangiogenic fate is specified not simply by the onset of Etv2 expression, but in a threshold-dependent manner. Importantly, VEGF-FLK1 signaling is necessary for efficiently achieving ETV2-threshold. Moreover, we find forkhead transcription factor Foxh1 to be required for FLK1 mesoderm formation. These studies provide a roadmap in hematopoietic and vascular cell generation and applications in regenerative medicine.
Project description:We discover that ER71/ETV2 initiates hemangiogenic program by activating blood and endothelial cell lineage specifying genes while enhancing FLK1 expression and expanding hemangioblast population. Furthermore, ER71/ETV2 establishes an ETS hierarchy by directly activating Ets genes in hematopoietic and endothelial cell lineage development. As such, ER71/ETV2-initiated blood and endothelial cell program is maintained by ER71/ETV2 downstream ETS factors through an ETS switching mechanism.
Project description:ETS transcription factors ETV2, FLI1 and ERG1 specify pluripotent stem cells into endothelial cells (PSC-ECs). However, these PSC-ECs are unstable and often drift towards non-vascular cell fates. We show that human mid-gestation c-Kit- lineage-committed amniotic cells (ACs) can be reprogrammed into induced vascular endothelial cells (rAC-VECs). Transient ETV2 expression in ACs generated immature iVECs, while co-expression with FLI1/ERG1 endowed rAC-VECs with a vascular repertoire and morphology matching mature ECs. Brief TGFb-inhibition functionalizes VEGFR2 signaling, augmenting specification of ACs into rAC-VECs. Genome-wide transcriptional analyses showed that rAC-VECs are similar to adult ECs in which vascular-specific genes are expressed and non-vascular genes are silenced. Functionally, rAC-VECs form stable vasculature in Matrigel plugs and regenerating livers. Thus, short-term ETV2 expression and TGFb-inhibition along with constitutive ERG1/FLI1 co-expression reprogram mature ACs into generic rAC-VECs with clinical-scale expansion potential. Public banking of HLA-typed rAC-VECs would establish a vascular inventory for treatment of genetically diverse disorders. Transcriptome sequencing of clonal and non-clonal rAC-VECs, HUVECs, LSECs, CD34+/Lin-, BMS
Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.