Vasculogenesis and angiogenesis in embryonic-stem-cell-derived embryoid bodies

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 471-478 ◽  
Author(s):  
W. Risau ◽  
H. Sariola ◽  
H.G. Zerwes ◽  
J. Sasse ◽  
P. Ekblom ◽  
...  

Embryonic stem cells (ESC) have been established previously from the inner cell mass cells of mouse blastocysts. In suspension culture, they spontaneously differentiate to blood-island-containing cystic embryoid bodies (CEB). The development of blood vessels from in situ differentiating endothelial cells of blood islands, a process which we call vasculogenesis, was induced by injecting ESC into the peritoneal cavity of syngeneic mice. In the peritoneum, fusion of blood islands and formation of an in vivo-like primary capillary plexus occurred. Transplantation of ESC and ESC-derived complex and cystic embryoid bodies (ESC-CEB) onto the quail chorioallantoic membrane (CAM) induced an angiogenic response, which was directed by nonyolk sac endoderm structures. Neither yolk sac endoderm from ESC-CEB nor normal mouse yolk sac tissue induced angiogenesis on the quail CAM. Extracts from ESC-CEB stimulated the proliferation of capillary endothelial cells in vitro. Mitogenic activity increase during in vitro culture and differentiation of ESC. Almost all growth factor activity was associated with the cells. The ESC-CEB derived endothelial cell growth factor bound to heparin-sepharose. The identification of acidic fibroblast growth factor (FGF)in heparin-sepharose-purified material was accomplished by immunoblot experiments involving antibodies against acidic and basic FGF. We conclude that vasculogenesis, the development of blood vessels from in situ differentiating endothelial cells, and angiogenesis, the sprouting of capillaries from preexisting vessels are very early events during embryogenesis which can be studied using ESC differentiating in vitro. Our results suggest that vasculogenesis and angiogenesis are differently regulated.

Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 361-372 ◽  
Author(s):  
Noah Byrd ◽  
Sandy Becker ◽  
Peter Maye ◽  
Roopa Narasimhaiah ◽  
Benoit St-Jacques ◽  
...  

Blood islands, the precursors of yolk sac blood vessels, contain primitive erythrocytes surrounded by a layer of endothelial cells. These structures differentiate from extra-embryonic mesodermal cells that underlie the visceral endoderm. Our previous studies have shown that Indian hedgehog (Ihh) is expressed in the visceral endoderm both in the visceral yolk sac in vivo and in embryonic stem (ES) cell-derived embryoid bodies. Differentiating embryoid bodies form blood islands, providing an in vitro model for studying vasculogenesis and hematopoiesis. A role for Ihh in yolk sac function is suggested by the observation that roughly 50% of Ihh–/– mice die at mid-gestation, potentially owing to vascular defects in the yolk sac. To address the nature of the possible vascular defects, we have examined the ability of ES cells deficient for Ihh or smoothened (Smo), which encodes a receptor component essential for all hedgehog signaling, to form blood islands in vitro. Embryoid bodies derived from these cell lines are unable to form blood islands, and express reduced levels of both PECAM1, an endothelial cell marker, and α-SMA, a vascular smooth muscle marker. RT-PCR analysis in the Ihh–/– lines shows a substantial decrease in the expression of Flk1 and Tal1, markers for the hemangioblast, the precursor of both blood and endothelial cells, as well as Flt1, an angiogenesis marker. To extend these observations, we have examined the phenotypes of embryo yolk sacs deficient for Ihh or Smo. Whereas Ihh–/– yolk sacs can form blood vessels, the vessels are fewer in number and smaller, perhaps owing to their inability to undergo vascular remodeling. Smo–/– yolk sacs arrest at an earlier stage: the endothelial tubes are packed with hematopoietic cells, and fail to undergo even the limited vascular remodeling observed in the Ihh–/– yolk sacs. Our study supports a role for hedgehog signaling in yolk sac angiogenesis.


Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 303-316 ◽  
Author(s):  
R. Wang ◽  
R. Clark ◽  
V.L. Bautch

Murine embryonic stem cells can differentiate in vitro to form cystic embryoid bodies (CEB) that contain different structures and cell types. The blood islands are one such structure that consist of immature hematopoietic cells surrounded by endothelial cells, the first identifiable vascular cells. CEBs differentiated in vitro developed blood islands initially, and subsequently these blood islands matured to form vascular channels containing hematopoietic cells. Phase contrast microscopy demonstrated the presence of channels in mature CEBs grown in suspension culture, and high resolution light and electron microscopy showed that the cells lining these channels were endothelial cells. The channels appeared less organized than the vasculature of the mature yolk sac. The hematopoietic cells were occasionally seen ‘flowing’ through the CEB channels, although their numbers were reduced relative to the yolk sac. Analysis of primary CEB cultures showed the presence of cells with two characteristics of endothelial cells: approximately 30% of the cells labelled with fluorescent acetylated low density lipoprotein and a small number of cells were positive for von Willebrand's factor by immunostaining. Thus we conclude that a primitive vasculature forms in CEBs differentiated in vitro, and that not only primary differentiation of endothelial cells but also some aspects of vascular maturation are intrinsic to this cell culture system. CEBs are therefore a useful model for the study of developmental blood vessel formation.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 138-138 ◽  
Author(s):  
Rita R. Perlingeiro

Abstract A critical role for endoglin (CD105) in early development has been demonstrated in mice deficient for this gene. Embryos homozygous for the endoglin mutation (eng−/−) fail to progress beyond 10.5 days postcoitum due primarily to vascular and cardiac abnormalities (Bordeau et al, 1999). Analysis of 9.5 dpc eng−/− embryos revealed abnormal vasculature and anemia of the yolk sac, suggesting that endoglin may be required for both blood and endothelial lineages. The hemangioblast, the bipotent precursor for hematopoietic and endothelial cells, can be assessed through the blast colony assay (BL-CFC) using a model system based on the in vitro differentiation of embryonic stem (ES) cells into embryoid bodies (EBs). To evaluate a role for endoglin in this early precursor, we differentiated eng−/−, eng+/−, and eng+/+ (wild-type) ES cells into EBs. At day 3 of EB differentiation, cells were disrupted and plated for blast colony formation in methylcellulose media containing vascular endothelial growth factor (VEGF), stem cell factor (SCF), and thrombopoietin (TPO). We found no difference in blast colony formation between heterozygous and wild-type ES cells. However, a significant reduction in the number of BL-CFCs was observed in eng−/− cells when compared to eng+/− or eng+/+ BL-CFCs (p < 0.001). Single eng−/−, eng+/−, and eng+/+ BL-CFCs gave rise to secondary hematopoietic colonies as well as endothelial cells, confirming their nature as hemangioblasts. These results suggest that although endoglin is required for hemangioblast development, its absence does not affect the bipotentiality of formed BL-CFCs. Since anemia was a feature of 9.5 dpc eng−/− yolk sac embryos, we also examined early erythropoiesis using the ES/EB system. For this purpose, eng−/−, eng+/−, and eng+/+ ES cells were differentiated into EBs for 4 days, at which time cells were disrupted and plated for primitive erythroid colonies (EryP) in methylcellulose media containing IL-3, IL-6, SCF, and Epo. We observed a reduction in the number of EryP colonies in eng−/− (p < 0.01) and eng+/− (p < 0.05) EBs when compared to controls (eng+/+). These results corroborate the anemia observed in vivo in the eng−/− embryos. We used RT-PCR and flow cytometry analysis to detect endoglin expression during a time course of EB differentiation. Endoglin is expressed in ES cells and disappears with differentiation. Expression re-appears at day 3 of differentiation, concomitantly with specification of the hemangioblast. Expression thereafter increases, correlating with mature endothelial cells at later time points. We did not find major differences in gene expression for Brachyury, Flk-1, Tie-2, embryonic and adult globins in a time course of EB differentiation for eng−/−, eng+/−, and eng+/+ ES cells. These data point out a role for endoglin, an ancillary receptor for several members of the transforming growth factor (TGF)-beta superfamily, in hemangioblast development.


Blood ◽  
1996 ◽  
Vol 88 (10) ◽  
pp. 3720-3730 ◽  
Author(s):  
M Bielinska ◽  
N Narita ◽  
M Heikinheimo ◽  
SB Porter ◽  
DB Wilson

During mouse embryogenesis the first hematopoietic and endothelial cells form in blood islands located between layers of visceral endoderm and mesoderm in the yolk sac. The role of visceral endoderm in primitive hematopoiesis and vasculogenesis is not well understood. We have assessed the consequences of a lack of visceral endoderm on blood cell and vessel formation using embryoid bodies derived from mouse embryonic stem (ES) cells deficient in GATA-4, a transcription factor expressed in yolk sac endoderm. When differentiated in vitro, these mutant embryoid bodies do not develop an external visceral endoderm layer. We found that Gata4-/-embryoid bodies, grown either in suspension culture or attached to a substratum, are defective in primitive hematopoiesis and vasculogenesis as evidenced by a lack of recognizable blood islands and vascular channels and a reduction in the expression of the primitive erythrocyte marker epsilon y-globin. Expression of the endothelial cell transcripts FIk-1, FIt-1, and platelet-endothelial cell adhesion molecule (PECAM) was not affected in the mutant embryoid bodies. Gata4-/-ES cells retained the capacity to differentiate into primitive erythroblasts and endothelial cells when cultured in methylcellulose or matrigel. Analysis of chimeric mice, generated by injecting Gata4-/-ES cells into 8-cell stage embryos of ROSA26 transgenic animals, showed that Gata4-/-ES cells can form blood islands and vessels when juxtaposed to visceral endoderm in vivo. We conclude that the visceral endoderm is not essential for the differentiation of primitive erythrocytes or endothelial cells, but this cell layer plays an important role in the formation and organization of yolk sac blood islands and vessels.


Blood ◽  
1996 ◽  
Vol 88 (9) ◽  
pp. 3424-3431 ◽  
Author(s):  
D Vittet ◽  
MH Prandini ◽  
R Berthier ◽  
A Schweitzer ◽  
H Martin-Sisteron ◽  
...  

The mechanisms involved in the regulation of vasculogenesis still remain unclear in mammals. Totipotent embryonic stem (ES) cells may represent a suitable in vitro model to study molecular events involved in vascular development. In this study, we followed the expression kinetics of a relatively large set of endothelial-specific markers in ES-derived embryoid bodies (EBs). Results of both reverse transcription-polymerase chain reaction and/or immunofluorescence analysis show that a spontaneous endothelial differentiation occurs during EBs development. ES-derived endothelial cells express a full range of cell lineage-specific markers: platelet endothelial cell adhesion molecule (PECAM), Flk-1, tie-1, tie-2, vascular endothelial (VE) cadherin, MECA-32, and MEC-14.7. Analysis of the kinetics of endothelial marker expression allows the distinction of successive maturation steps. Flk-1 was the first to be detected; its mRNA is apparent from day 3 of differentiation. PECAM and tie-2 mRNAs were found to be expressed only from day 4, whereas VE-cadherin and tie-1 mRNAs cannot be detected before day 5. Immunofluorescence stainings of EBs with antibodies directed against Flk-1, PECAM, VE-cadherin, MECA-32, and MEC-14.7 confirmed that the expression of these antigens occurs at different steps of endothelial cell differentiation. The addition of an angiogenic growth factor mixture including erythropoietin, interleukin-6, fibroblast growth factor 2, and vascular endothelial growth factor in the EB culture medium significantly increased the development of primitive vascular-like structures within EBs. These results indicate that this in vitro system contains a large part of the endothelial cell differentiation program and constitutes a suitable model to study the molecular mechanisms involved in vasculogenesis.


2000 ◽  
Vol 11 (12) ◽  
pp. 4295-4308 ◽  
Author(s):  
Anna Gualandris ◽  
Justin P. Annes ◽  
Marco Arese ◽  
Irene Noguera ◽  
Vladimir Jurukovski ◽  
...  

The latent transforming growth factor-β–binding protein-1 (LTBP-1) belongs to a family of extracellular glycoproteins that includes three additional isoforms (LTBP-2, -3, and -4) and the matrix proteins fibrillin-1 and -2. Originally described as a TGF-β–masking protein, LTBP-1 is involved both in the sequestration of latent TGF-β in the extracellular matrix and the regulation of its activation in the extracellular environment. Whereas the expression of LTBP-1 has been analyzed in normal and malignant cells and rodent and human tissues, little is known about LTBP-1 in embryonic development. To address this question, we used murine embryonic stem (ES) cells to analyze the appearance and role of LTBP-1 during ES cell differentiation. In vitro, ES cells aggregate to form embryoid bodies (EBs), which differentiate into multiple cell lineages. We analyzed LTBP-1 gene expression and LTBP-1 fiber appearance with respect to the emergence and distribution of cell types in differentiating EBs. LTBP-1 expression increased during the first 12 d in culture, appeared to remain constant between d 12 and 24, and declined thereafter. By immunostaining, fibrillar LTBP-1 was observed in those regions of the culture containing endothelial, smooth muscle, and epithelial cells. We found that inclusion of a polyclonal antibody to LTBP-1 during EB differentiation suppressed the expression of the endothelial specific genes ICAM-2 and von Willebrand factor and delayed the organization of differentiated endothelial cells into cord-like structures within the growing EBs. The same effect was observed when cultures were treated with either antibodies to TGF-β or the latency associated peptide, which neutralize TGF-β. Conversely, the organization of endothelial cells was enhanced by incubation with TGF-β1. These results suggest that during differentiation of ES cells LTBP-1 facilitates endothelial cell organization via a TGF-β–dependent mechanism.


Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3755-3764 ◽  
Author(s):  
N. Narita ◽  
M. Bielinska ◽  
D.B. Wilson

In situ hybridization studies, promoter analyses and antisense RNA experiments have implicated transcription factor GATA-4 in the regulation of cardiomyocyte differentiation. In this study, we utilized Gata4−/− embryonic stem (ES) cells to determine whether this transcription factor is essential for cardiomyocyte lineage commitment. First, we assessed the ability of Gata4−/− ES cells form cardiomyocytes during in vitro differentiation of embryoid bodies. Contracting cardiomyocytes were seen in both wild-type and Gata4−/− embryoid bodies, although cardiomyocytes were observed more often in wild type than in mutant embryoid bodies. Electron microscopy of cardiomyocytes in the Gata4−/− embryoid bodies revealed the presence of sarcomeres and junctional complexes, while immunofluorescence confirmed the presence of cardiac myosin. To assess the capacity of Gata4−/− ES cells to differentiate into cardiomyocytes in vivo, we prepared and analyzed chimeric mice. Gata4−/− ES cells were injected into 8-cell-stage embryos derived from ROSA26 mice, a transgenic line that expresses beta-galactosidase in all cell types. Chimeric embryos were stained with X-gal to discriminate ES cell- and host-derived tissue. Gata4−/− ES cells contributed to endocardium, myocardium and epicardium. In situ hybridization showed that myocardium derived from Gata4−/− ES cells expressed several cardiac-specific transcripts, including cardiac alpha-myosin heavy chain, troponin C, myosin light chain-2v, Nkx-2.5/Csx, dHAND, eHAND and GATA-6. Taken together these results indicate that GATA-4 is not essential for terminal differentiation of cardiomyocytes and suggest that additional GATA-binding proteins known to be in cardiac tissue, such as GATA-5 or GATA-6, may compensate for a lack of GATA-4.


Blood ◽  
2003 ◽  
Vol 101 (5) ◽  
pp. 1818-1826 ◽  
Author(s):  
Shripad V. Bhagwat ◽  
Nenad Petrovic ◽  
Yasuhiro Okamoto ◽  
Linda H. Shapiro

Angiogenesis, the formation of new blood vessels, is a critical step for tumor growth and metastasis and an integral component of the pathologic inflammatory response in arthritis and the proliferative retinopathies. The CD13/aminopeptidase N (CD13/APN) metalloprotease is an important regulator of angiogenesis where its expression on activated blood vessels is induced by angiogenic signals. Here, we show that cytokine induction of CD13/APN in endothelial cells is regulated by distinct Ras effector pathways involving Ras/mitogen-activated protein kinase (MAPK) or PI-3K. Signals transduced by activated Ras, Raf, and mitogen-induced extracellular kinase (MEK) stimulate transcription from theCD13/APN proximal promoter. Inhibition of these pathways and extracellular signal–regulated serine/threonine kinase (ERK-2) and PI-3K by expression of dominant-negative proteins or chemical inhibitors prevented induction of CD13/APNtranscription in response to basic fibroblast growth factor (bFGF). We show that Ras-induced signal transduction is required for growth factor–induced angiogenesis, because inhibition of downstream mediators of Ras signaling (MEK or PI-3K) abrogated endothelial cell migration, invasion, and morphogenesis in vitro. Reintroduction of CD13/APN, a shared downstream target of these pathways, overrode the suppressive effect of these inhibitors and restored the function of endothelial cells in migration/invasion and capillary morphogenesis assays. Similarly, inhibition of MEK abrogated cell invasion and the formation of endothelial-lined capillaries in vivo, which was effectively rescued by addition of exogenous CD13/APN protein. These studies provide strong evidence that CD13/APN is an important target of Ras signaling in angiogenesis and is a limiting factor in angiogenic progression.


2004 ◽  
Vol 287 (6) ◽  
pp. C1560-C1568 ◽  
Author(s):  
Sanjay Sinha ◽  
Mark H. Hoofnagle ◽  
Paul A. Kingston ◽  
Mary E. McCanna ◽  
Gary K. Owens

Knockout of transforming growth factor (TGF)-β1 or components of its signaling pathway leads to embryonic death in mice due to impaired yolk sac vascular development before significant smooth muscle cell (SMC) maturation occurs. Thus the role of TGF-β1 in SMC development remains unclear. Embryonic stem cell (ESC)-derived embryoid bodies (EBs) recapitulate many of the events of early embryonic development and represent a more physiological context in which to study SMC development than most other in vitro systems. The present studies showed induction of the SMC-selective genes smooth muscle α-actin (SMαA), SM22α, myocardin, smoothelin-B, and smooth muscle myosin heavy chain (SMMHC) within a mouse ESC-EB model system. Significantly, SM2, the SMMHC isoform associated with fully differentiated SMCs, was expressed. Importantly, the results showed that aggregates of SMMHC-expressing cells exhibited visible contractile activity, suggesting that all regulatory pathways essential for development of contractile SMCs were functional in this in vitro model system. Inhibition of endogenous TGF-β with an adenovirus expressing a soluble truncated TGF-β type II receptor attenuated the increase in SMC-selective gene expression in the ESC-EBs, as did an antibody specific for TGF-β1. Of interest, the results of small interfering (si)RNA experiments provided evidence for differential TGF-β-Smad signaling for an early vs. late SMC marker gene in that SMαA promoter activity was dependent on both Smad2 and Smad3 whereas SMMHC activity was Smad2 dependent. These results are the first to provide direct evidence that TGF-β1 signaling through Smad2 and Smad3 plays an important role in the development of SMCs from totipotential ESCs.


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