这是一篇介绍血液血管干细胞的很好的综述。如果做血液血管干细胞的同志,这篇综述应该是很好的参考。

[Cell Cycle 2:2, 86-90, March/April 2003]; © 2003 Landes Bioscience

Spotlight on Cardiology

The Hemangioblast

Between Blood and Vessels

The Walter and Eliza Hall Institute of Medical Research; Parkville, Victoria, Australia *Correspondence to: L Robb; The Walter and Eliza Hall Institute of Medical Research;1G Royal Parade; Victoria, 3050, Australia; Email: robb@wehi.edu.auReceived 01/29/03; Accepted 02/10/03

Previously published online as a Cell Cycle“Paper In Press” at www.1mpi.com

INTRODUCTION

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Work in the authors' laboratory is funded by The National Health and MedicalResearch Council of Australia, The Cooperative Research Centre for Cellular Growthfactors and the Sylvia and Charles Viertel Charitable Foundation.

Early last century, studies into the origin of blood cells and blood vessels in avianembryos revealed that blood and endothelial cells arise synchronously in the yolk sac instructures known as blood islands.1,2Blood islands initially appear as compact, morpho-logically identical, cell clusters. As development proceeds, the inner cells become primitiveerythrocytes and the outer cells acquire the morphology of endothelial cells.3Theerythrocytes then break free, creating a lumen within the blood island and, with theestablishment of the vascular plexus, circulate. These anatomical studies led to the coiningof the word hemangioblast to describe a putative bipotential precursor cell within theblood island which gave rise to blood and endothelial cells.4However, cytologicalobservations alone were insufficient to prove the existence of the hemangioblast. In the lastdecade, the concept of the hemangioblast has gained support from studies demonstratingthat the hematopoietic and endothelial lineages share expression of multiple genes5-8andfrom gene targeting experiments which have revealed genes which are required for thedevelopment of both lineages.9-11In addition, zebrafish mutagenesis studies have identifieda mutant, known as cloche, which lacks both hematopoietic cells and endocardium.12These observations support the concept of a close ontological relationship betweenendothelial and hematopoietic lineages, but do not specifically prove the existence of thehemangioblast.13As described below, the most compelling evidence in favour of this hascome from in vitro experiments using murine embryonic stem (ES) cells.

The last few years have seen the emergence of the concept of adult stem cell plasticity(reviewed in refs. 14 and 15) and the term hemangioblast has recently been applied to sort-ed subsets of adult hematopoietic stem cells that can give rise to blood and endothelialcells.16,17Given that these cells, when subjected to appropriate exogenous stimuli, can alsodevelop into a range of other cell types they could reasonably be described as multilineagestem cells, rather than hemangioblasts. As originally defined, and for the purposes of thisreview, the term hemangioblast denotes a progenitor cell, present in the early embryo,which gives rise only to blood and endothelial cells. Here we briefly describe the developmentof hematopoiesis in the embryo, taking, unless otherwise stated, the mouse as a model andthen examine experimental evidence for the existence of the hemangioblast.

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KEY WORDS

The hemangioblast is a bipotential cell that gives rise to hematopoietic and endothelialcells. Although the existence of the hemangioblast was first postulated early last century,a cell with this activity has yet to be unequivocally identified in mammals. In the lastdecade, gene targeting experiments in the mouse have uncovered genes which arerequired for development of both the hematopoietic and endothelial lineages, and this,together with increasing recognition that the two cell types share gene expression patterns,has renewed interest in the hemangioblast. The murine embryonic stem cell differentiationsystem has been used to demonstrate the existence of a Flk-1 positive progenitor cell,called the BL-CFC, which has the properties of the hemangioblast and this system isnow being used to dissect the molecular regulation of hemangioblast development anddifferentiation.

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Ariel Forrai Lorraine Robb*

ABSTRACT

2003; Vol. 2 Issue 2