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eXtraembryonic ENdoderm (XEN) stem cells produce factors that activate heart formation.

Brown K, Doss MX, Legros S, Artus J, Hadjantonakis AK, Foley AC - PLoS ONE (2010)

Bottom Line: These studies represent the first step in the use of XEN cells as a molecular genetic tool to study cardiomyocyte differentiation.Not only are XEN cells functionally similar to the heart-inducing AVE, but also can be used for the genetic dissection of the cardiogenic potential of AVE, since they can be isolated from both wild type and mutant blastocysts.These studies further demonstrate the importance of both contact-dependent and contact-independent factors in cardiogenesis and identify potential heart-inducing proteins in the endoderm.

View Article: PubMed Central - PubMed

Affiliation: Greenberg Division of Cardiology, Weill Cornell Medical College, New York, New York, United States of America.

ABSTRACT

Background: Initial specification of cardiomyocytes in the mouse results from interactions between the extraembryonic anterior visceral endoderm (AVE) and the nascent mesoderm. However the mechanism by which AVE activates cardiogenesis is not well understood, and the identity of specific cardiogenic factors in the endoderm remains elusive. Most mammalian studies of the cardiogenic potential of the endoderm have relied on the use of cell lines that are similar to the heart-inducing AVE. These include the embryonal-carcinoma-derived cell lines, END2 and PYS2. The recent development of protocols to isolate eXtraembryonic ENdoderm (XEN) stem cells, representing the extraembryonic endoderm lineage, from blastocyst stage mouse embryos offers new tools for the genetic dissection of cardiogenesis.

Methodology/principal findings: Here, we demonstrate that XEN cell-conditioned media (CM) enhances cardiogenesis during Embryoid Body (EB) differentiation of mouse embryonic stem (ES) cells in a manner comparable to PYS2-CM and END2-CM. Addition of CM from each of these three cell lines enhanced the percentage of EBs that formed beating areas, but ultimately, only XEN-CM and PYS2-CM increased the total number of cardiomyocytes that formed. Furthermore, our observations revealed that both contact-independent and contact-dependent factors are required to mediate the full cardiogenic potential of the endoderm. Finally, we used gene array comparison to identify factors in these cell lines that could mediate their cardiogenic potential.

Conclusions/significance: These studies represent the first step in the use of XEN cells as a molecular genetic tool to study cardiomyocyte differentiation. Not only are XEN cells functionally similar to the heart-inducing AVE, but also can be used for the genetic dissection of the cardiogenic potential of AVE, since they can be isolated from both wild type and mutant blastocysts. These studies further demonstrate the importance of both contact-dependent and contact-independent factors in cardiogenesis and identify potential heart-inducing proteins in the endoderm.

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Related in: MedlinePlus

Additional extracellular factors identified by Gene Ontology are expressed by heart inducing cell lines.Normalized expression in the array, expressed as a heat map, of the remaining 38 Venn-restricted factors that were detected as present in the array based on a detection p-value<0.01.
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pone-0013446-g010: Additional extracellular factors identified by Gene Ontology are expressed by heart inducing cell lines.Normalized expression in the array, expressed as a heat map, of the remaining 38 Venn-restricted factors that were detected as present in the array based on a detection p-value<0.01.

Mentions: To expand the list of candidate secreted factors that might account for the cardiac inducing ability of these extraembryonic endodermal cell lines, we analyzed the expression of the remaining 222 Venn-restricted genes. The largest group (comprising 28 genes) of the remaining Venn-restricted genes were members of the TGFbeta superfamily of signaling molecules (Figure 9A). Of these, the three extraembryonic endodermal cell lines expressed only six genes, including TGFbeta-1 and -2. This finding is consistent with our previous observation that all components of known TGFbeta signaling pathways are present in these cell lines [28]. Another 17 Venn-restricted terms comprised other growth factors, of which 8 were expressed in at least one of the cell lines (Figure 9B). While not included in the Venn-restricted data set, we also assessed the presence of Wnt family members and BMP antagonists (Figure 9C) since these signaling pathways have been extensively implicated in the early phases of cardiac specification. We found that all of the cell lines expressed the BMP antagonists Follistatin and Noggin, but only three Wnt family members, Wnt11, Wnt4 and Wnt7b were expressed. Finally, of the 175 remaining Venn-restricted terms, 38 were expressed in at least one of the cell lines (Figure 10). These data represent a comprehensive set of secreted factors with known receptor binding activity that are expressed in cells lines possessing heart inducing ability.


eXtraembryonic ENdoderm (XEN) stem cells produce factors that activate heart formation.

Brown K, Doss MX, Legros S, Artus J, Hadjantonakis AK, Foley AC - PLoS ONE (2010)

Additional extracellular factors identified by Gene Ontology are expressed by heart inducing cell lines.Normalized expression in the array, expressed as a heat map, of the remaining 38 Venn-restricted factors that were detected as present in the array based on a detection p-value<0.01.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2958120&req=5

pone-0013446-g010: Additional extracellular factors identified by Gene Ontology are expressed by heart inducing cell lines.Normalized expression in the array, expressed as a heat map, of the remaining 38 Venn-restricted factors that were detected as present in the array based on a detection p-value<0.01.
Mentions: To expand the list of candidate secreted factors that might account for the cardiac inducing ability of these extraembryonic endodermal cell lines, we analyzed the expression of the remaining 222 Venn-restricted genes. The largest group (comprising 28 genes) of the remaining Venn-restricted genes were members of the TGFbeta superfamily of signaling molecules (Figure 9A). Of these, the three extraembryonic endodermal cell lines expressed only six genes, including TGFbeta-1 and -2. This finding is consistent with our previous observation that all components of known TGFbeta signaling pathways are present in these cell lines [28]. Another 17 Venn-restricted terms comprised other growth factors, of which 8 were expressed in at least one of the cell lines (Figure 9B). While not included in the Venn-restricted data set, we also assessed the presence of Wnt family members and BMP antagonists (Figure 9C) since these signaling pathways have been extensively implicated in the early phases of cardiac specification. We found that all of the cell lines expressed the BMP antagonists Follistatin and Noggin, but only three Wnt family members, Wnt11, Wnt4 and Wnt7b were expressed. Finally, of the 175 remaining Venn-restricted terms, 38 were expressed in at least one of the cell lines (Figure 10). These data represent a comprehensive set of secreted factors with known receptor binding activity that are expressed in cells lines possessing heart inducing ability.

Bottom Line: These studies represent the first step in the use of XEN cells as a molecular genetic tool to study cardiomyocyte differentiation.Not only are XEN cells functionally similar to the heart-inducing AVE, but also can be used for the genetic dissection of the cardiogenic potential of AVE, since they can be isolated from both wild type and mutant blastocysts.These studies further demonstrate the importance of both contact-dependent and contact-independent factors in cardiogenesis and identify potential heart-inducing proteins in the endoderm.

View Article: PubMed Central - PubMed

Affiliation: Greenberg Division of Cardiology, Weill Cornell Medical College, New York, New York, United States of America.

ABSTRACT

Background: Initial specification of cardiomyocytes in the mouse results from interactions between the extraembryonic anterior visceral endoderm (AVE) and the nascent mesoderm. However the mechanism by which AVE activates cardiogenesis is not well understood, and the identity of specific cardiogenic factors in the endoderm remains elusive. Most mammalian studies of the cardiogenic potential of the endoderm have relied on the use of cell lines that are similar to the heart-inducing AVE. These include the embryonal-carcinoma-derived cell lines, END2 and PYS2. The recent development of protocols to isolate eXtraembryonic ENdoderm (XEN) stem cells, representing the extraembryonic endoderm lineage, from blastocyst stage mouse embryos offers new tools for the genetic dissection of cardiogenesis.

Methodology/principal findings: Here, we demonstrate that XEN cell-conditioned media (CM) enhances cardiogenesis during Embryoid Body (EB) differentiation of mouse embryonic stem (ES) cells in a manner comparable to PYS2-CM and END2-CM. Addition of CM from each of these three cell lines enhanced the percentage of EBs that formed beating areas, but ultimately, only XEN-CM and PYS2-CM increased the total number of cardiomyocytes that formed. Furthermore, our observations revealed that both contact-independent and contact-dependent factors are required to mediate the full cardiogenic potential of the endoderm. Finally, we used gene array comparison to identify factors in these cell lines that could mediate their cardiogenic potential.

Conclusions/significance: These studies represent the first step in the use of XEN cells as a molecular genetic tool to study cardiomyocyte differentiation. Not only are XEN cells functionally similar to the heart-inducing AVE, but also can be used for the genetic dissection of the cardiogenic potential of AVE, since they can be isolated from both wild type and mutant blastocysts. These studies further demonstrate the importance of both contact-dependent and contact-independent factors in cardiogenesis and identify potential heart-inducing proteins in the endoderm.

Show MeSH
Related in: MedlinePlus