Endothelio-hematopoietic relationship: getting closer to the beginnings

Abstract

The close association between hematopoietic and endothelial cells during embryonic development led to the proposal that they may originate from a common ancestor - the hemangioblast. Due to a lack of unique specific markers for in vivo cell fate tracking studies, evidence supporting this theory derives mainly from in vitro differentiation studies. Teixeira and colleagues describe a novel enhancer that drives specific eGFP expression in blood islands of the electroporated chick embryo, thereby presenting a tool potentially suitable for analysis of hemangioblast differentiation and development of blood islands.See research article: http://www.biomedcentral.com/1471-213X/11/76

Making a Hematopoietic Stem Cell

“…Later efforts focused on recapitulating embryonic hematopoietic development by differentiating PSCs. PSCs can now be differentiated into hemogenic endothelium (HE) , the progenitor cell population theorized to give rise to HSCs as part of an embryonic site of hematopoiesis called the aorta-gonad-mesonephros [39–42]. Recent data demonstrate that different populations of HE give rise to the primitive and definitive hematopoietic programs within these hematopoietic sites [43].…”

Inflammatory signaling regulates hematopoietic stem and progenitor cell emergence in vertebrates

“…In vertebrate embryos, the earliest definitive hematopoietic stem and progenitor cells (HSPCs) are originated from a group of specialized endothelial cells, hemogenic endothelium (HE), [1][2][3][4] through the endothelial-to-hematopoietic transition (EHT) process. [5][6][7] In vitro generation and/or expansion of functional and transplantable bona fide HSCs with self-renewal and multilineage potential hold great promise in regenerative medicine.…”

Targeting the vascular endothelial growth factor in hematologic malignancies

“…The physiological role of the vascular endothelial growth factor (VEGF)/VEGF‐receptor signaling system is first of all the regulation of the formation of blood vessels (angiogenesis) and blood cells (hematopoiesis) . Endothelial and hematopoietic cell lineages are thereby supposed to be initiated from the same precursor cells , and regulatory loops by which VEGF controls the survival of hematopoietic stem cells (HSCs) have been described . Several primary cells and cell lines representing hematologic neoplastic diseases express functional vascular endothelial growth factor receptors (VEGF‐Rs), and their signaling influences survival, proliferation, and migration .…”