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Karen M Downs - One of the best experts on this subject based on the ideXlab platform.
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the mouse fetal placental arterial connection a paradigm involving the primitive streak and visceral endoderm with implications for human development
Wiley Interdisciplinary Reviews-Developmental Biology, 2020Co-Authors: Karen M Downs, Adriana M RodriguezAbstract:In Placentalia, the fetus depends upon an organized vascular connection with its mother for survival and development. Yet, this connection was, until recently, obscure. Here, we summarize how two unrelated tissues, the primitive streak, or body axis, and extraembryonic visceral endoderm collaborate to create and organize the fetal-placental arterial connection in the mouse gastrula. The primitive streak reaches into the extraembryonic space, where it marks the site of arterial union and creates a progenitor cell pool. Through contact with the streak, associated visceral endoderm undergoes an epithelial-to-mesenchymal transition, contributing extraembryonic mesoderm to the placental arterial vasculature, and to the Allantois, or pre-umbilical tissue. In addition, visceral endoderm bifurcates into the Allantois where, with the primitive streak, it organizes the nascent umbilical artery and promotes allantoic elongation to the chorion, the site of fetal-maternal exchange. Brachyury mediates streak extension and vascular patterning, while Hedgehog is involved in visceral endoderm's conversion to mesoderm. A unique CASPASE-3-positive cell separates streak- and non-streak-associated domains in visceral endoderm. Based on these new insights at the posterior embryonic-extraembryonic interface, we conclude by asking whether so-called primordial germ cells are truly antecedents to the germ line that segregate within the Allantois, or whether they are placental progenitor cells. Incorporating these new working hypotheses into mutational analyses in which the placentae are affected will aid understanding a spectrum of disorders, including orphan diseases, which often include abnormalities of the umbilical cord, yolk sac, and hindgut, whose developmental relationship to each other has, until now, been poorly understood. This article is categorized under: Birth Defects > Associated with Preimplantation and Gastrulation Early Embryonic Development > Gastrulation and Neurulation.
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visceral endoderm and the primitive streak interact to build the fetal placental interface of the mouse gastrula
Developmental Biology, 2017Co-Authors: Adriana M Rodriguez, Karen M DownsAbstract:Hypoblast/visceral endoderm assists in amniote nutrition, axial positioning and formation of the gut. Here, we provide evidence, currently limited to humans and non-human primates, that hypoblast is a purveyor of extraembryonic mesoderm in the mouse gastrula. Fate mapping a unique segment of axial extraembryonic visceral endoderm associated with the allantoic component of the primitive streak, and referred to as the "AX", revealed that visceral endoderm supplies the placentae with extraembryonic mesoderm. Exfoliation of the AX was dependent upon contact with the primitive streak, which modulated Hedgehog signaling. Resolution of the AX's epithelial-to-mesenchymal transition (EMT) by Hedgehog shaped the Allantois into its characteristic projectile and individualized placental arterial vessels. A unique border cell separated the delaminating AX from the yolk sac blood islands which, situated beyond the limit of the streak, were not formed by an EMT. Over time, the AX became the hindgut lip, which contributed extensively to the posterior interface, including both embryonic and extraembryonic tissues. The AX, in turn, imparted antero-posterior (A-P) polarity on the primitive streak and promoted its elongation and differentiation into definitive endoderm. Results of heterotopic grafting supported mutually interactive functions of the AX and primitive streak, showing that together, they self-organized into a complete version of the fetal-placental interface, forming an elongated structure that exhibited A-P polarity and was composed of the Allantois, an AX-derived rod-like axial extension reminiscent of the embryonic notochord, the placental arterial vasculature and visceral endoderm/hindgut.
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brachyury drives formation of a distinct vascular branchpoint critical for fetal placental arterial union in the mouse gastrula
Developmental Biology, 2017Co-Authors: Adriana M Rodriguez, Maria M. Mikedis, Dexter X Jin, Adam D Wolfe, Lauren Wierenga, Maleka P Hashmi, Christoph Viebahn, Karen M DownsAbstract:How the fetal-placental arterial connection is made and positioned relative to the embryonic body axis, thereby ensuring efficient and directed blood flow to and from the mother during gestation, is not known. Here we use a combination of genetics, timed pharmacological inhibition in living mouse embryos, and three-dimensional modeling to link two novel architectural features that, at present, have no status in embryological atlases. The allantoic core domain (ACD) is the extraembryonic extension of the primitive streak into the Allantois, or pre-umbilical tissue; the vessel of confluence (VOC), situated adjacent to the ACD, is an extraembryonic vessel that marks the site of fetal-placental arterial union. We show that genesis of the fetal-placental connection involves the ACD and VOC in a series of steps, each one dependent upon the last. In the first, Brachyury (T) ensures adequate extension of the primitive streak into the Allantois, which in turn designates the allantoic-yolk sac junction. Next, the streak-derived ACD organizes allantoic angioblasts to the axial junction; upon signaling from Fibroblast Growth Factor Receptor-1 (FGFR1), these endothelialize and branch, forming a sprouting VOC that unites the umbilical and omphalomesenteric arteries with the fetal dorsal aortae. Arterial union is followed by the appearance of the medial umbilical roots within the VOC, which in turn designate the correct axial placement of the lateral umbilical roots/common iliac arteries. In addition, we show that the ACD and VOC are conserved across Placentalia, including humans, underscoring their fundamental importance in mammalian biology. We conclude that T is required for correct axial positioning of the VOC via the primitive streak/ACD, while FGFR1, through its role in endothelialization and branching, further patterns it. Together, these genetic, molecular and structural elements safeguard the fetus against adverse outcomes that can result from vascular mispatterning of the fetal-placental arterial connection.
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stella collaborates in distinct mesendodermal cell subpopulations at the fetal placental interface in the mouse gastrula
Developmental Biology, 2017Co-Authors: Adam D Wolfe, Adriana M Rodriguez, Karen M DownsAbstract:The Allantois-derived umbilical component of the chorio-allantoic placenta shuttles fetal blood to and from the chorion, thereby ensuring fetal-maternal exchange. The progenitor populations that establish and supply the fetal-umbilical interface lie, in part, within the base of the Allantois, where the germ line is claimed to segregate from the soma. Results of recent studies in the mouse have reported that STELLA (DPPA-3, PGC7) co-localizes with PRDM1 (BLIMP1), the bimolecular signature of putative primordial germ cells (PGCs) throughout the fetal-placental interface. Thus, if PGCs form extragonadally within the posterior region of the mammal, they cannot be distinguished from the soma on the basis of these proteins. We used immunohistochemistry, immunofluorescence, and confocal microscopy of the mouse gastrula to co-localize STELLA with a variety of gene products, including pluripotency factor OCT-3/4, mesendoderm-associated T and MIXl1, mesendoderm- and endoderm-associated FOXa2 and hematopoietic factor Runx1. While a subpopulation of cells localizing OCT-3/4 was always found independently of STELLA, STELLA always co-localized with OCT-3/4. Despite previous reports that T is involved in specification of the germ line, co-localization of STELLA and T was detected only in a small subset of cells in the base of the Allantois. Slightly later in the hindgut lip, STELLA+/(OCT-3/4+) co-localized with FOXa2, as well as with RUNX1, indicative of definitive endoderm and hemangioblasts, respectively. STELLA was never found with MIXl1. On the basis of these and previous results, we conclude that STELLA identifies at least five distinct cell subpopulations within the Allantois and hindgut, where they may be involved in mesendodermal differentiation and hematopoiesis at the posterior embryonic-extraembryonic interface. These data provide a new point of departure for understanding STELLA's potential roles in building the fetal-placental connection.
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prdm1 blimp1 is widely distributed to the nascent fetal placental interface in the mouse gastrula
Developmental Dynamics, 2017Co-Authors: Maria M. Mikedis, Karen M DownsAbstract:Background: PRDM1 is a transcriptional repressor that contributes to primordial germ cell (PGC) development. During early gastrulation, epiblast-derived PRDM1 is thought to be restricted to a lineage-segregated germ line in the Allantois. However, given recent findings that PGCs overlap an allantoic progenitor pool that contributes widely to the fetal-umbilical interface, posterior PRDM1 may also contribute to soma. Results: Within the posterior mouse gastrula (Early Streak – 12-s stages, ∼E6.75-9.0), PRDM1 localized to all tissues containing putative PGCs; however, PRDM1 was also found in all three primary germ layers, their derivatives, and two presumptive growth centers, the Allantoic Core Domain and Ventral Ectodermal Ridge. While PRDM1 and STELLA colocalized predominantly within the hindgut, where putative PGCs reside, other colocalizing cells were found in non-PGC sites. Additional PRDM1 and STELLA cells were found independent of each other throughout the posterior region, including the hindgut. The Prdm1-Cre-driven reporter supported PRDM1 localization in the majority of sites; however, some Prdm1 descendants were found in sites independent of PRDM1 protein, including allantoic mesothelium and hindgut endoderm. Conclusion: Posterior PRDM1 contributes more broadly to the developing fetal-maternal connection than previously recognized, and PRDM1 and STELLA, while overlapping in putative PGCs, also co-localize in several other tissues. This article is protected by copyright. All rights reserved.
Adriana M Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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the mouse fetal placental arterial connection a paradigm involving the primitive streak and visceral endoderm with implications for human development
Wiley Interdisciplinary Reviews-Developmental Biology, 2020Co-Authors: Karen M Downs, Adriana M RodriguezAbstract:In Placentalia, the fetus depends upon an organized vascular connection with its mother for survival and development. Yet, this connection was, until recently, obscure. Here, we summarize how two unrelated tissues, the primitive streak, or body axis, and extraembryonic visceral endoderm collaborate to create and organize the fetal-placental arterial connection in the mouse gastrula. The primitive streak reaches into the extraembryonic space, where it marks the site of arterial union and creates a progenitor cell pool. Through contact with the streak, associated visceral endoderm undergoes an epithelial-to-mesenchymal transition, contributing extraembryonic mesoderm to the placental arterial vasculature, and to the Allantois, or pre-umbilical tissue. In addition, visceral endoderm bifurcates into the Allantois where, with the primitive streak, it organizes the nascent umbilical artery and promotes allantoic elongation to the chorion, the site of fetal-maternal exchange. Brachyury mediates streak extension and vascular patterning, while Hedgehog is involved in visceral endoderm's conversion to mesoderm. A unique CASPASE-3-positive cell separates streak- and non-streak-associated domains in visceral endoderm. Based on these new insights at the posterior embryonic-extraembryonic interface, we conclude by asking whether so-called primordial germ cells are truly antecedents to the germ line that segregate within the Allantois, or whether they are placental progenitor cells. Incorporating these new working hypotheses into mutational analyses in which the placentae are affected will aid understanding a spectrum of disorders, including orphan diseases, which often include abnormalities of the umbilical cord, yolk sac, and hindgut, whose developmental relationship to each other has, until now, been poorly understood. This article is categorized under: Birth Defects > Associated with Preimplantation and Gastrulation Early Embryonic Development > Gastrulation and Neurulation.
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visceral endoderm and the primitive streak interact to build the fetal placental interface of the mouse gastrula
Developmental Biology, 2017Co-Authors: Adriana M Rodriguez, Karen M DownsAbstract:Hypoblast/visceral endoderm assists in amniote nutrition, axial positioning and formation of the gut. Here, we provide evidence, currently limited to humans and non-human primates, that hypoblast is a purveyor of extraembryonic mesoderm in the mouse gastrula. Fate mapping a unique segment of axial extraembryonic visceral endoderm associated with the allantoic component of the primitive streak, and referred to as the "AX", revealed that visceral endoderm supplies the placentae with extraembryonic mesoderm. Exfoliation of the AX was dependent upon contact with the primitive streak, which modulated Hedgehog signaling. Resolution of the AX's epithelial-to-mesenchymal transition (EMT) by Hedgehog shaped the Allantois into its characteristic projectile and individualized placental arterial vessels. A unique border cell separated the delaminating AX from the yolk sac blood islands which, situated beyond the limit of the streak, were not formed by an EMT. Over time, the AX became the hindgut lip, which contributed extensively to the posterior interface, including both embryonic and extraembryonic tissues. The AX, in turn, imparted antero-posterior (A-P) polarity on the primitive streak and promoted its elongation and differentiation into definitive endoderm. Results of heterotopic grafting supported mutually interactive functions of the AX and primitive streak, showing that together, they self-organized into a complete version of the fetal-placental interface, forming an elongated structure that exhibited A-P polarity and was composed of the Allantois, an AX-derived rod-like axial extension reminiscent of the embryonic notochord, the placental arterial vasculature and visceral endoderm/hindgut.
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brachyury drives formation of a distinct vascular branchpoint critical for fetal placental arterial union in the mouse gastrula
Developmental Biology, 2017Co-Authors: Adriana M Rodriguez, Maria M. Mikedis, Dexter X Jin, Adam D Wolfe, Lauren Wierenga, Maleka P Hashmi, Christoph Viebahn, Karen M DownsAbstract:How the fetal-placental arterial connection is made and positioned relative to the embryonic body axis, thereby ensuring efficient and directed blood flow to and from the mother during gestation, is not known. Here we use a combination of genetics, timed pharmacological inhibition in living mouse embryos, and three-dimensional modeling to link two novel architectural features that, at present, have no status in embryological atlases. The allantoic core domain (ACD) is the extraembryonic extension of the primitive streak into the Allantois, or pre-umbilical tissue; the vessel of confluence (VOC), situated adjacent to the ACD, is an extraembryonic vessel that marks the site of fetal-placental arterial union. We show that genesis of the fetal-placental connection involves the ACD and VOC in a series of steps, each one dependent upon the last. In the first, Brachyury (T) ensures adequate extension of the primitive streak into the Allantois, which in turn designates the allantoic-yolk sac junction. Next, the streak-derived ACD organizes allantoic angioblasts to the axial junction; upon signaling from Fibroblast Growth Factor Receptor-1 (FGFR1), these endothelialize and branch, forming a sprouting VOC that unites the umbilical and omphalomesenteric arteries with the fetal dorsal aortae. Arterial union is followed by the appearance of the medial umbilical roots within the VOC, which in turn designate the correct axial placement of the lateral umbilical roots/common iliac arteries. In addition, we show that the ACD and VOC are conserved across Placentalia, including humans, underscoring their fundamental importance in mammalian biology. We conclude that T is required for correct axial positioning of the VOC via the primitive streak/ACD, while FGFR1, through its role in endothelialization and branching, further patterns it. Together, these genetic, molecular and structural elements safeguard the fetus against adverse outcomes that can result from vascular mispatterning of the fetal-placental arterial connection.
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stella collaborates in distinct mesendodermal cell subpopulations at the fetal placental interface in the mouse gastrula
Developmental Biology, 2017Co-Authors: Adam D Wolfe, Adriana M Rodriguez, Karen M DownsAbstract:The Allantois-derived umbilical component of the chorio-allantoic placenta shuttles fetal blood to and from the chorion, thereby ensuring fetal-maternal exchange. The progenitor populations that establish and supply the fetal-umbilical interface lie, in part, within the base of the Allantois, where the germ line is claimed to segregate from the soma. Results of recent studies in the mouse have reported that STELLA (DPPA-3, PGC7) co-localizes with PRDM1 (BLIMP1), the bimolecular signature of putative primordial germ cells (PGCs) throughout the fetal-placental interface. Thus, if PGCs form extragonadally within the posterior region of the mammal, they cannot be distinguished from the soma on the basis of these proteins. We used immunohistochemistry, immunofluorescence, and confocal microscopy of the mouse gastrula to co-localize STELLA with a variety of gene products, including pluripotency factor OCT-3/4, mesendoderm-associated T and MIXl1, mesendoderm- and endoderm-associated FOXa2 and hematopoietic factor Runx1. While a subpopulation of cells localizing OCT-3/4 was always found independently of STELLA, STELLA always co-localized with OCT-3/4. Despite previous reports that T is involved in specification of the germ line, co-localization of STELLA and T was detected only in a small subset of cells in the base of the Allantois. Slightly later in the hindgut lip, STELLA+/(OCT-3/4+) co-localized with FOXa2, as well as with RUNX1, indicative of definitive endoderm and hemangioblasts, respectively. STELLA was never found with MIXl1. On the basis of these and previous results, we conclude that STELLA identifies at least five distinct cell subpopulations within the Allantois and hindgut, where they may be involved in mesendodermal differentiation and hematopoiesis at the posterior embryonic-extraembryonic interface. These data provide a new point of departure for understanding STELLA's potential roles in building the fetal-placental connection.
Naomi Kitamura - One of the best experts on this subject based on the ideXlab platform.
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placental defect and embryonic lethality in mice lacking hepatocyte growth factor scatter factor
Nature, 1995Co-Authors: Yoshihiko Uehara, Osamu Minowa, Junko Kuno, Chisato Mori, Kohei Shiota, Tetsuo Noda, Naomi KitamuraAbstract:HEPATOCYTE growth factor/scatter factor (HGF/SF) functions as a mitogen, motogen and morphogen for a variety of cultured cells1–7. The genes for HGF/SF and its receptor (the c-met protooncogene product8) are expressed in many tissues during the embryonic periods and in the adult9–14. HGF/SF is thought to mediate a signal exchange between the mesenchyme and epithelia during mouse development15. To examine the physiological role of HGF/SF, we generated mutant mice with a targeted disruption of the HGF/SF gene. Here we report that homozygous mutant embryos have severely impaired placentas with markedly reduced numbers of labyrinthine trophoblast cells, and die before birth. The growth of trophoblast cells was stimulated by HGF/SF in vitro, and the HGF/SF activity was released by Allantois in primary culture of normal but not mutant embryos. These findings suggest that HGF/SF is an essential mediator of allantoic mesenchyme-trophoblastic epithelia interaction required for placental organogenesis.
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placental defect and embryonic lethality in mice lacking hepatocyte growth factor scatter factor
Nature, 1995Co-Authors: Yoshihiko Uehara, Osamu Minowa, Junko Kuno, Chisato Mori, Kohei Shiota, Tetsuo Noda, Naomi KitamuraAbstract:HEPATOCYTE growth factor/scatter factor (HGF/SF) functions as a mitogen, motogen and morphogen for a variety of cultured cells1–7. The genes for HGF/SF and its receptor (the c-met protooncogene product8) are expressed in many tissues during the embryonic periods and in the adult9–14. HGF/SF is thought to mediate a signal exchange between the mesenchyme and epithelia during mouse development15. To examine the physiological role of HGF/SF, we generated mutant mice with a targeted disruption of the HGF/SF gene. Here we report that homozygous mutant embryos have severely impaired placentas with markedly reduced numbers of labyrinthine trophoblast cells, and die before birth. The growth of trophoblast cells was stimulated by HGF/SF in vitro, and the HGF/SF activity was released by Allantois in primary culture of normal but not mutant embryos. These findings suggest that HGF/SF is an essential mediator of allantoic mesenchyme-trophoblastic epithelia interaction required for placental organogenesis.
Maria M. Mikedis - One of the best experts on this subject based on the ideXlab platform.
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brachyury drives formation of a distinct vascular branchpoint critical for fetal placental arterial union in the mouse gastrula
Developmental Biology, 2017Co-Authors: Adriana M Rodriguez, Maria M. Mikedis, Dexter X Jin, Adam D Wolfe, Lauren Wierenga, Maleka P Hashmi, Christoph Viebahn, Karen M DownsAbstract:How the fetal-placental arterial connection is made and positioned relative to the embryonic body axis, thereby ensuring efficient and directed blood flow to and from the mother during gestation, is not known. Here we use a combination of genetics, timed pharmacological inhibition in living mouse embryos, and three-dimensional modeling to link two novel architectural features that, at present, have no status in embryological atlases. The allantoic core domain (ACD) is the extraembryonic extension of the primitive streak into the Allantois, or pre-umbilical tissue; the vessel of confluence (VOC), situated adjacent to the ACD, is an extraembryonic vessel that marks the site of fetal-placental arterial union. We show that genesis of the fetal-placental connection involves the ACD and VOC in a series of steps, each one dependent upon the last. In the first, Brachyury (T) ensures adequate extension of the primitive streak into the Allantois, which in turn designates the allantoic-yolk sac junction. Next, the streak-derived ACD organizes allantoic angioblasts to the axial junction; upon signaling from Fibroblast Growth Factor Receptor-1 (FGFR1), these endothelialize and branch, forming a sprouting VOC that unites the umbilical and omphalomesenteric arteries with the fetal dorsal aortae. Arterial union is followed by the appearance of the medial umbilical roots within the VOC, which in turn designate the correct axial placement of the lateral umbilical roots/common iliac arteries. In addition, we show that the ACD and VOC are conserved across Placentalia, including humans, underscoring their fundamental importance in mammalian biology. We conclude that T is required for correct axial positioning of the VOC via the primitive streak/ACD, while FGFR1, through its role in endothelialization and branching, further patterns it. Together, these genetic, molecular and structural elements safeguard the fetus against adverse outcomes that can result from vascular mispatterning of the fetal-placental arterial connection.
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prdm1 blimp1 is widely distributed to the nascent fetal placental interface in the mouse gastrula
Developmental Dynamics, 2017Co-Authors: Maria M. Mikedis, Karen M DownsAbstract:Background: PRDM1 is a transcriptional repressor that contributes to primordial germ cell (PGC) development. During early gastrulation, epiblast-derived PRDM1 is thought to be restricted to a lineage-segregated germ line in the Allantois. However, given recent findings that PGCs overlap an allantoic progenitor pool that contributes widely to the fetal-umbilical interface, posterior PRDM1 may also contribute to soma. Results: Within the posterior mouse gastrula (Early Streak – 12-s stages, ∼E6.75-9.0), PRDM1 localized to all tissues containing putative PGCs; however, PRDM1 was also found in all three primary germ layers, their derivatives, and two presumptive growth centers, the Allantoic Core Domain and Ventral Ectodermal Ridge. While PRDM1 and STELLA colocalized predominantly within the hindgut, where putative PGCs reside, other colocalizing cells were found in non-PGC sites. Additional PRDM1 and STELLA cells were found independent of each other throughout the posterior region, including the hindgut. The Prdm1-Cre-driven reporter supported PRDM1 localization in the majority of sites; however, some Prdm1 descendants were found in sites independent of PRDM1 protein, including allantoic mesothelium and hindgut endoderm. Conclusion: Posterior PRDM1 contributes more broadly to the developing fetal-maternal connection than previously recognized, and PRDM1 and STELLA, while overlapping in putative PGCs, also co-localize in several other tissues. This article is protected by copyright. All rights reserved.
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STELLA-positive subregions of the primitive streak contribute to posterior tissues of the mouse gastrula.
Developmental biology, 2011Co-Authors: Maria M. Mikedis, Karen M DownsAbstract:Abstract The developmental relationship between the posterior embryonic and extraembryonic regions of the mammalian gastrula is poorly understood. Although many different cell types are deployed within this region, only the primordial germ cells (PGCs) have been closely studied. Recent evidence has suggested that the Allantois, within which the PGCs temporarily take up residence, contains a pool of cells, called the Allantoic Core Domain (ACD), critical for allantoic elongation to the chorion. Here, we have asked whether the STELLA-positive cells found within this region, thought to be specified PGCs, are actually part of the ACD and to what extent they, and other ACD cells, contribute to the Allantois and fetal tissues. To address these hypotheses, STELLA was immunolocalized to the mouse gastrula between Early Streak (ES) and 12-somite pair (-s) stages (~ 6.75–9.0 days post coitum, dpc) in histological sections. STELLA was found in both the nucleus and cytoplasm in a variety of cell types, both within and outside of the putative PGC trajectory. Fate-mapping the headfold-stage (~ 7.75–8.0 dpc) posterior region, by which time PGCs are thought to be segregated into a distinct lineage, revealed that the STELLA-positive proximal ACD and intraembryonic posterior primitive streak (IPS) contributed to a wide range of somatic tissues that encompassed derivatives of the three primary germ layers. This contribution included STELLA-positive cells localizing to tissues both within and outside of the putative PGC trajectory. Thus, while STELLA may identify a subpopulation of cells destined for the PGC lineage, our findings reveal that it may be part of a broader niche that encompasses the ACD and through which the STELLA population may contribute cells to a wide variety of posterior tissues of the mouse gastrula.
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collagen type iv and perlecan exhibit dynamic localization in the allantoic core domain a putative stem cell niche in the murine Allantois
Developmental Dynamics, 2009Co-Authors: Maria M. Mikedis, Karen M DownsAbstract:A body of evidence suggests that the murine Allantois contains a stem cell niche, the Allantoic Core Domain (ACD), that may contribute to a variety of allantoic and embryonic cell types. Given that extracellular matrix (ECM) regulates cell fate and function in niches, the Allantois was systematically examined for Collagen type IV (ColIV) and Perlecan, both of which are associated with stem cell proliferation and differentiation. Not only was localization of ColIV and Perlecan more widespread during gastrulation than previously reported, but protein localization profiles were particularly robust and dynamic within the Allantois and associated visceral endoderm as the ACD formed and matured. We propose that these data provide further evidence that the ACD is a stem cell niche whose activity is synchronized with associated visceral endoderm, possibly via ECM proteins.
Francoise Dieterlenlievre - One of the best experts on this subject based on the ideXlab platform.
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hematopoietic potential of the pre fusion Allantois
Developmental Biology, 2007Co-Authors: Catherine Corbel, Francoise Dieterlenlievre, Josselyne Salaun, Patricia BelodiabangouayaAbstract:We previously showed that the fetal component of the placenta has a vigorous hematopoietic activity. Whether this organ is an environmental niche where hematopoietic stem cells (HSC) proliferate and become committed to various lineages, or whether it is also a site for HSC emergence, was left open. This issue can be addressed only if the components that will give rise to the placenta are tested prior to vascularization. The fetal part of the placenta forms through the fusion of the Allantois and the chorionic plate around the stage of 7 somite pairs. The Allantois, a mesodermal rudiment that provides fetal blood vessels to the placenta, was retrieved before fusion. We found in this rudiment expression of CD41, a known marker of early embryonic hematopoietic progenitors. c-Kit encoding a progenitor specific receptor was also expressed. Significantly, as early as the 1-2 somite stage, the Allantois yielded erythroid, myeloid and multipotent clonogenic progenitors, when pre-cultured in toto prior to seeding in a semisolid medium. These results provide evidence that the Allantois has hematopoietic potential per se. Whether this potential also involves the ability to produce HSC is still to be determined.
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hemangioblast commitment in the avian Allantois cellular and molecular aspects
Developmental Biology, 2001Co-Authors: Anne Eichmann, Krisztina Minko, Cecile Drevon, Arianna Caprioli, Francoise Dieterlenlievre, Thierry JaffredoAbstract:Abstract We recently identified the Allantois as a site producing hemopoietic and endothelial cells capable of colonizing the bone marrow of an engrafted host. Here, we report a detailed investigation of some early cytological and molecular processes occurring in the allantoic bud, which are probably involved in the production of angioblasts and hemopoietic cells. We show that the Allantois undergoes a program characterized by the prominent expression of several “hemangioblastic” genes in the mesoderm accompanied by other gene patterns in the associated endoderm. VEGF-R2, at least from stage HH17 onward, is expressed and is shortly followed by transcription factors GATA-2, SCL/tal-1, and GATA-1. Blood island-like structures differentiate that contain both CD45+ cells and cells accumulating hemoglobin; these structures look exactly like blood islands in the yolk sac. This hemopoietic process takes place before the establishment of a vascular network connecting the Allantois to the embryo. As far as the endoderm is concerned, GATA-3 mRNA is found in the region where Allantois will differentiate before the posterior instestinal portal becomes anatomically distinct. Shortly before the bud grows out, GATA-2 was expressed in the endoderm and, at the same time, the hemangioblastic program became initiated in the mesoderm. GATA-3 is detected at least until E8 and GATA-2 until E3 the latest stage examined for this factor. Using in vitro cultures, we show that allantoic buds, dissected out before the establishment of circulation between the bud and the rest of the embryo, produced erythrocytes of the definitive lineage. Moreover, using heterospecific grafts between chick and quail embryos, we demonstrate that the allantoic vascular network develops from intrinsic progenitors. Taken together, these results extend our earlier findings about the commitment of mesoderm to the endothelial and hemopoietic lineages in the Allantois. The detection of a prominent GATA-3 expression restricted to the endoderm of the preallantoic region and allantoic bud, followed by that of GATA-2, is an interesting and novel information, in the context of organ formation and endoderm specification in the emergence of hemopoietic cells.
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blood borne seeding by hematopoietic and endothelial precursors from the Allantois
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Arianna Caprioli, Thierry Jaffredo, Rodolphe Gautier, Cecile Dubourg, Francoise DieterlenlievreAbstract:Until now the Allantois has not been considered as a hematopoietic organ. Here we report experimental evidence demonstrating the in situ emergence of both hematopoietic and endothelial precursors in the avian allantoic bud. When the prevascularized allantoic bud from a quail embryo was grafted in the coelom of a chicken host, hematopoietic and endothelial cells later were found in the bone marrow of the host. Because the graft was located at a distance from the limb bud, these cells could reach the bone marrow only by the circulatory pathway. This blood-borne seeding may be accomplished by distinct hematopoietic and endothelial precursors, or by hemangioblasts, the postulated common precursors of these two lineages; we consider the latter interpretation more likely. We also show by reverse transcription–PCR that the Allantois region expresses very early the GATA genes involved in hematopoiesis and some β-globin chain genes.