Blastocyst Development - Revision history

Z8600021 at 07:50, 7 December 2021

2021-12-07T07:50:19Z

← Older revision		Revision as of 17:50, 7 December 2021
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			* '''Human blastoids model blastocyst development and implantation''' {{#pmid:34856602\|PMID34856602}} "One week after fertilization, human embryos implant into the uterus. This event requires that the embryo forms a blastocyst consisting of a sphere encircling a cavity lodging the embryo proper. Stem cells can form a blastocyst model, which we termed blastoid1. Here we show that naive human pluripotent stem cells (PXGL hPSCs)2 triply inhibited for the Hippo, TGF-β, and ERK pathways efficiently (>70%) form blastoids generating blastocyst-stage analogs of the 3 founding lineages (>97% trophectoderm, {{epiblast}}, and primitive endoderm) according to the sequence and timing of blastocyst development. Blastoids spontaneously form the first axis and we observe that the epiblast induces the maturation of the polar trophectoderm that consequently acquires the specific capacity to attach to hormonally-stimulated endometrial cells, as during implantation. Such a human blastoid is a faithful, scalable, and ethical model to explore human implantation and development."

	* '''Computational analysis of single-cell transcriptomics data elucidates the stabilization of Oct4 expression in the E3.25 mouse preimplantation embryo''' {{#pmid:31222057\|PMID31222057}} "Our computational analysis focuses on the 32- to 64-cell {{mouse}} embryo transition, Embryonic day (3.25), whose study in literature is concentrated mainly on the search for an early onset of the second cell-fate decision, the specification of the inner cell mass (ICM) to primitive endoderm (PE) and epiblast (EPI). We analysed single-cell (sc) microarray transcriptomics data from E3.25 using Hierarchical Optimal k-Means (HOkM) clustering, and identified two groups of ICM cells: a group of cells from embryos with less than 34 cells (E3.25-LNCs), and another group of cells from embryos with more than 33 cells (E3.25-HNCs), corresponding to two developmental stages. Although we found massive underlying heterogeneity in the ICM cells at E3.25-HNC with over 3,800 genes with transcriptomics bifurcation, many of which are PE and EPI markers, we showed that the E3.25-HNCs are neither PE nor EPI. Importantly, analysing the differently expressed genes between the E3.25-LNCs and E3.25-HNCs, we uncovered a non-autonomous mechanism, based on a minimal number of four inner-cell contacts in the ICM, which activates Oct4 in the preimplantation embryo. Oct4 is highly expressed but unstable at E3.25-LNC, and stabilizes at high level at E3.25-HNC, with Bsg highly expressed, and the chromatin remodelling program initialised to establish an early naïve pluripotent state. Our results indicate that the pluripotent state we found to exist in the ICM at E3.25-HNC is the in vivo counterpart of a new, very early pluripotent state. We compared the transcriptomics profile of this in vivo E3.25-HNC pluripotent state, together with the profiles of E3.25-LNC, E3.5 EPI and E4.5 EPI cells, with the profiles of all embryonic stem cells (ESCs) available in the GEO database from the same platform (over 600 microarrays)."		* '''Computational analysis of single-cell transcriptomics data elucidates the stabilization of Oct4 expression in the E3.25 mouse preimplantation embryo''' {{#pmid:31222057\|PMID31222057}} "Our computational analysis focuses on the 32- to 64-cell {{mouse}} embryo transition, Embryonic day (3.25), whose study in literature is concentrated mainly on the search for an early onset of the second cell-fate decision, the specification of the inner cell mass (ICM) to primitive endoderm (PE) and epiblast (EPI). We analysed single-cell (sc) microarray transcriptomics data from E3.25 using Hierarchical Optimal k-Means (HOkM) clustering, and identified two groups of ICM cells: a group of cells from embryos with less than 34 cells (E3.25-LNCs), and another group of cells from embryos with more than 33 cells (E3.25-HNCs), corresponding to two developmental stages. Although we found massive underlying heterogeneity in the ICM cells at E3.25-HNC with over 3,800 genes with transcriptomics bifurcation, many of which are PE and EPI markers, we showed that the E3.25-HNCs are neither PE nor EPI. Importantly, analysing the differently expressed genes between the E3.25-LNCs and E3.25-HNCs, we uncovered a non-autonomous mechanism, based on a minimal number of four inner-cell contacts in the ICM, which activates Oct4 in the preimplantation embryo. Oct4 is highly expressed but unstable at E3.25-LNC, and stabilizes at high level at E3.25-HNC, with Bsg highly expressed, and the chromatin remodelling program initialised to establish an early naïve pluripotent state. Our results indicate that the pluripotent state we found to exist in the ICM at E3.25-HNC is the in vivo counterpart of a new, very early pluripotent state. We compared the transcriptomics profile of this in vivo E3.25-HNC pluripotent state, together with the profiles of E3.25-LNC, E3.5 EPI and E4.5 EPI cells, with the profiles of all embryonic stem cells (ESCs) available in the GEO database from the same platform (over 600 microarrays)."

	* '''Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts'''{{#pmid:30952696\|PMID30952696}} "Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species."		* '''Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts'''{{#pmid:30952696\|PMID30952696}} "Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species."

	* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."

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	\| {{Older papers}}		\| {{Older papers}}
			* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."

	* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."		* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."

Z8600021 at 23:06, 26 March 2020

2020-03-26T23:06:45Z

← Older revision		Revision as of 09:06, 27 March 2020
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	The blastocyst consists of cells forming an outer '''trophectoderm''' (TE, trophoblast) layer, an '''inner cell mass''' (ICM, embryo blast) and a blastocoel (fluid-filled cavity). The ~~blastocyst~~ inner cell mass is the source of true embryonic stem cells capable of forming all cell types within the embryo.		The blastocyst consists of cells forming an outer '''{{trophectoderm}}''' (TE, {{trophoblast}}) layer, an '''inner cell mass''' (ICM, embryo blast) and a blastocoel (fluid-filled cavity). The inner cell mass will form the entire embryo, and is the source of true embryonic stem cells capable of forming all cell types within the embryo. In mammals, the {{trophectoderm}} will form key cells ({{trophoblast}}) of the fatal component of the {{placenta}}.


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	One of the first key developmental patterning decisions in the morula to blastocyst development is TE or ICM cell fate. In the mouse model, ~~[[Developmental Signals -~~ Hippo~~\|Hippo]]~~{{#pmid:25986053\|PMID25986053}}(TEAD4) and ~~[[Developmental Signals -~~ Notch~~\|Notch]]~~{{#pmid:25127056\|PMID25127056}}(Cdx2) together appear regulate this early fate decision.		One of the first key developmental patterning decisions in the morula to blastocyst development is TE or ICM cell fate. In the mouse model, {{Hippo}}{{#pmid:25986053\|PMID25986053}}(TEAD4) and {{Notch}}{{#pmid:25127056\|PMID25127056}}(Cdx2) together appear regulate this early fate decision.

	{{Blastocyst Links}}		{{Blastocyst Links}}
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	* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."		* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."

	* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."

	\|}		\|}
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	\|-		\|-
	\| {{Older papers}}		\| {{Older papers}}
			* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."

	* '''Oct4 is required for lineage priming in the developing inner cell mass of the mouse blastocyst'''{{#pmid:24504341\|PMID24504341}} "The transcription factor Oct4 is required in vitro for establishment and maintenance of embryonic stem cells and for reprogramming somatic cells to pluripotency. In vivo, it prevents the ectopic differentiation of early embryos into trophoblast. Here, we further explore the role of Oct4 in blastocyst formation and specification of epiblast versus primitive endoderm lineages using conditional genetic deletion. Experiments involving mouse embryos deficient for both maternal and zygotic Oct4 suggest that it is dispensable for zygote formation, early cleavage and activation of Nanog expression. Nanog protein is significantly elevated in the presumptive inner cell mass of Oct4 null embryos, suggesting an unexpected role for Oct4 in attenuating the level of Nanog, which might be significant for priming differentiation during epiblast maturation. Induced deletion of Oct4 during the morula to blastocyst transition disrupts the ability of inner cell mass cells to adopt lineage-specific identity and acquire the molecular profile characteristic of either epiblast or primitive endoderm. Sox17, a marker of primitive endoderm, is not detected following prolonged culture of such embryos, but can be rescued by provision of exogenous FGF4. Interestingly, functional primitive endoderm can be rescued in Oct4-deficient embryos in embryonic stem cell complementation assays, but only if the host embryos are at the pre-blastocyst stage. We conclude that cell fate decisions within the inner cell mass are dependent upon Oct4 and that Oct4 is not cell-autonomously required for the differentiation of primitive endoderm derivatives, as long as an appropriate developmental environment is established."		* '''Oct4 is required for lineage priming in the developing inner cell mass of the mouse blastocyst'''{{#pmid:24504341\|PMID24504341}} "The transcription factor Oct4 is required in vitro for establishment and maintenance of embryonic stem cells and for reprogramming somatic cells to pluripotency. In vivo, it prevents the ectopic differentiation of early embryos into trophoblast. Here, we further explore the role of Oct4 in blastocyst formation and specification of epiblast versus primitive endoderm lineages using conditional genetic deletion. Experiments involving mouse embryos deficient for both maternal and zygotic Oct4 suggest that it is dispensable for zygote formation, early cleavage and activation of Nanog expression. Nanog protein is significantly elevated in the presumptive inner cell mass of Oct4 null embryos, suggesting an unexpected role for Oct4 in attenuating the level of Nanog, which might be significant for priming differentiation during epiblast maturation. Induced deletion of Oct4 during the morula to blastocyst transition disrupts the ability of inner cell mass cells to adopt lineage-specific identity and acquire the molecular profile characteristic of either epiblast or primitive endoderm. Sox17, a marker of primitive endoderm, is not detected following prolonged culture of such embryos, but can be rescued by provision of exogenous FGF4. Interestingly, functional primitive endoderm can be rescued in Oct4-deficient embryos in embryonic stem cell complementation assays, but only if the host embryos are at the pre-blastocyst stage. We conclude that cell fate decisions within the inner cell mass are dependent upon Oct4 and that Oct4 is not cell-autonomously required for the differentiation of primitive endoderm derivatives, as long as an appropriate developmental environment is established."

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	==Trophectoderm==		==Trophectoderm==
	The {{trophectoderm}} (TE) outer layer of smaller cells is also called the "trophoblast" epithelium. A key early function is for the transport of sodium (Na+) and chloride (Cl-) ions through this layer into the blastocoel. Later in week 2 this layer will differentiate into two distinct {{trophoblast}} layers the {{syncytiotrophoblast}} and {{cytotrophoblast}} cells and are key to implantation and early placentation.		The {{trophectoderm}} (TE) outer layer of smaller cells is also called the "trophoblast" epithelium, that will later form a key component of the {{placenta}}. A key early function is for the transport of sodium (Na+) and chloride (Cl-) ions through this layer into the blastocoel. Later in week 2 this layer will differentiate into two distinct {{trophoblast}} layers the {{syncytiotrophoblast}} and {{cytotrophoblast}} cells and are key to implantation and early placentation.

Z8600021 at 20:01, 1 Ocak 2020

2020-01-01T20:01:40Z

← Older revision		Revision as of 06:01, 2 Ocak 2020
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	{{Blastocyst Links}}		{{Blastocyst Links}}
	<br>		<br>
	[[File:Blastomere genomic divergence 01.jpg\|\|thumb~~\|250px~~\|alt=Blastomere genomic divergence\|Blastomere genomic divergence{{#pmid:30836937\|PMID30836937}}]]		[[File:Blastomere genomic divergence 01.jpg\|\|thumb\|alt=Blastomere genomic divergence\|Blastomere genomic divergence{{#pmid:30836937\|PMID30836937}}]]
	[[File:Mouse blastocyst development 01.jpg\|thumb\|alt=Mouse blastocyst development\|Mouse blastocyst development{{#pmid:28700688\|PMID28700688}}]]		[[File:Mouse blastocyst development 01.jpg\|thumb\|alt=Mouse blastocyst development\|Mouse blastocyst development{{#pmid:28700688\|PMID28700688}}]]
	== Some Recent Findings ==		== Some Recent Findings ==

Z8600021 at 20:01, 1 Ocak 2020

2020-01-01T20:01:17Z

← Older revision		Revision as of 06:01, 2 Ocak 2020
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	{{Blastocyst Links}}		{{Blastocyst Links}}
			<br>
			[[File:Blastomere genomic divergence 01.jpg\|\|thumb\|250px\|alt=Blastomere genomic divergence\|Blastomere genomic divergence{{#pmid:30836937\|PMID30836937}}]]
	[[File:Mouse blastocyst development 01.jpg\|thumb\|alt=Mouse blastocyst development\|Mouse blastocyst development{{#pmid:28700688\|PMID28700688}}]]		[[File:Mouse blastocyst development 01.jpg\|thumb\|alt=Mouse blastocyst development\|Mouse blastocyst development{{#pmid:28700688\|PMID28700688}}]]
	== Some Recent Findings ==		== Some Recent Findings ==

Z8600021 at 19:51, 1 Ocak 2020

2020-01-01T19:51:37Z

← Older revision		Revision as of 05:51, 2 Ocak 2020
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	===Articles===		===Articles===
			{{#pmid:30836937}}

	{{#pmid:20157423}}		{{#pmid:20157423}}

Z8600021 at 02:37, 27 Haziran 2019

2019-06-27T02:37:59Z

← Older revision		Revision as of 12:37, 27 Haziran 2019
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			* '''Computational analysis of single-cell transcriptomics data elucidates the stabilization of Oct4 expression in the E3.25 mouse preimplantation embryo''' {{#pmid:31222057\|PMID31222057}} "Our computational analysis focuses on the 32- to 64-cell {{mouse}} embryo transition, Embryonic day (3.25), whose study in literature is concentrated mainly on the search for an early onset of the second cell-fate decision, the specification of the inner cell mass (ICM) to primitive endoderm (PE) and epiblast (EPI). We analysed single-cell (sc) microarray transcriptomics data from E3.25 using Hierarchical Optimal k-Means (HOkM) clustering, and identified two groups of ICM cells: a group of cells from embryos with less than 34 cells (E3.25-LNCs), and another group of cells from embryos with more than 33 cells (E3.25-HNCs), corresponding to two developmental stages. Although we found massive underlying heterogeneity in the ICM cells at E3.25-HNC with over 3,800 genes with transcriptomics bifurcation, many of which are PE and EPI markers, we showed that the E3.25-HNCs are neither PE nor EPI. Importantly, analysing the differently expressed genes between the E3.25-LNCs and E3.25-HNCs, we uncovered a non-autonomous mechanism, based on a minimal number of four inner-cell contacts in the ICM, which activates Oct4 in the preimplantation embryo. Oct4 is highly expressed but unstable at E3.25-LNC, and stabilizes at high level at E3.25-HNC, with Bsg highly expressed, and the chromatin remodelling program initialised to establish an early naïve pluripotent state. Our results indicate that the pluripotent state we found to exist in the ICM at E3.25-HNC is the in vivo counterpart of a new, very early pluripotent state. We compared the transcriptomics profile of this in vivo E3.25-HNC pluripotent state, together with the profiles of E3.25-LNC, E3.5 EPI and E4.5 EPI cells, with the profiles of all embryonic stem cells (ESCs) available in the GEO database from the same platform (over 600 microarrays)."

	* '''Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts'''{{#pmid:30952696\|PMID30952696}} "Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species."		* '''Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts'''{{#pmid:30952696\|PMID30952696}} "Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species."

Z8600021 at 08:49, 5 Mayıs 2019

2019-05-05T08:49:06Z

← Older revision		Revision as of 18:49, 5 Mayıs 2019
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			* '''Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts'''{{#pmid:30952696\|PMID30952696}} "Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species."

	* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."		* '''Four simple rules that are sufficient to generate the mammalian blastocyst'''{{#pmid:28700688\|PMID28700688}} "We implemented experimentally reported mechanisms for polarity, cell-cell signaling, adhesion, and apoptosis as a set of developmental rules in an agent-based in silico model of physically interacting cells. We find that this model quantitatively reproduces specific mutant phenotypes and provides an explanation for the emergence of heterogeneity without requiring any initial transcriptional variation. It also suggests that a fixed time point for the cells' competence of fibroblast growth factor (FGF)/extracellular signal-regulated kinase (ERK) sets an embryonic clock that enables certain scaling phenomena, a concept that we evaluate quantitatively by manipulating embryos in vitro. Based on these observations, we conclude that the minimal set of rules enables the embryo to experiment with stochastic gene expression and could provide the robustness necessary for the evolutionary diversification of the preimplantation gene regulatory network."

Z8600021 at 08:45, 5 Mayıs 2019

2019-05-05T08:45:38Z

← Older revision		Revision as of 18:45, 5 Mayıs 2019
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	* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."		* '''Asymmetric division of contractile domains couples cell positioning and fate specification'''{{#pmid:27487217\|PMID27487217}} "During pre-implantation development, the mammalian embryo self-organizes into the blastocyst, which consists of an epithelial layer encapsulating the inner-cell mass (ICM) giving rise to all embryonic tissues. In mice, oriented cell division, apicobasal polarity and actomyosin contractility are thought to contribute to the formation of the ICM. However, how these processes work together remains unclear. Here we show that asymmetric segregation of the apical domain generates blastomeres with different contractilities, which triggers their sorting into inner and outer positions."

	* '''Oct4 is required for lineage priming in the developing inner cell mass of the mouse blastocyst'''{{#pmid:24504341\|PMID24504341}} "The transcription factor Oct4 is required in vitro for establishment and maintenance of embryonic stem cells and for reprogramming somatic cells to pluripotency. In vivo, it prevents the ectopic differentiation of early embryos into trophoblast. Here, we further explore the role of Oct4 in blastocyst formation and specification of epiblast versus primitive endoderm lineages using conditional genetic deletion. Experiments involving mouse embryos deficient for both maternal and zygotic Oct4 suggest that it is dispensable for zygote formation, early cleavage and activation of Nanog expression. Nanog protein is significantly elevated in the presumptive inner cell mass of Oct4 null embryos, suggesting an unexpected role for Oct4 in attenuating the level of Nanog, which might be significant for priming differentiation during epiblast maturation. Induced deletion of Oct4 during the morula to blastocyst transition disrupts the ability of inner cell mass cells to adopt lineage-specific identity and acquire the molecular profile characteristic of either epiblast or primitive endoderm. Sox17, a marker of primitive endoderm, is not detected following prolonged culture of such embryos, but can be rescued by provision of exogenous FGF4. Interestingly, functional primitive endoderm can be rescued in Oct4-deficient embryos in embryonic stem cell complementation assays, but only if the host embryos are at the pre-blastocyst stage. We conclude that cell fate decisions within the inner cell mass are dependent upon Oct4 and that Oct4 is not cell-autonomously required for the differentiation of primitive endoderm derivatives, as long as an appropriate developmental environment is established."
	\|}		\|}
	{\| class="wikitable mw-collapsible mw-collapsed"		{\| class="wikitable mw-collapsible mw-collapsed"
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	\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}		\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}

	Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Blastocyst+Development ''Blastocyst Development'']		Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Blastocyst+Development ''Blastocyst Development''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Blastocyst ''Blastocyst''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Blastocoel ''Blastocoel''] \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Inner+Cell+Mass ''Inner Cell Mass''] \| \| [http://www.ncbi.nlm.nih.gov/pubmed/?term=Trophectoderm ''Trophectoderm'']

	<pubmed ~~limit~~=5>Blastocyst ~~Development<~~/pubmed>
	\|}		\|}
	{\| class="wikitable mw-collapsible mw-collapsed"		{\| class="wikitable mw-collapsible mw-collapsed"
	! Older papers		! Older papers
	\|-		\|-
	\|		\| {{Older papers}}
			* '''Oct4 is required for lineage priming in the developing inner cell mass of the mouse blastocyst'''{{#pmid:24504341\|PMID24504341}} "The transcription factor Oct4 is required in vitro for establishment and maintenance of embryonic stem cells and for reprogramming somatic cells to pluripotency. In vivo, it prevents the ectopic differentiation of early embryos into trophoblast. Here, we further explore the role of Oct4 in blastocyst formation and specification of epiblast versus primitive endoderm lineages using conditional genetic deletion. Experiments involving mouse embryos deficient for both maternal and zygotic Oct4 suggest that it is dispensable for zygote formation, early cleavage and activation of Nanog expression. Nanog protein is significantly elevated in the presumptive inner cell mass of Oct4 null embryos, suggesting an unexpected role for Oct4 in attenuating the level of Nanog, which might be significant for priming differentiation during epiblast maturation. Induced deletion of Oct4 during the morula to blastocyst transition disrupts the ability of inner cell mass cells to adopt lineage-specific identity and acquire the molecular profile characteristic of either epiblast or primitive endoderm. Sox17, a marker of primitive endoderm, is not detected following prolonged culture of such embryos, but can be rescued by provision of exogenous FGF4. Interestingly, functional primitive endoderm can be rescued in Oct4-deficient embryos in embryonic stem cell complementation assays, but only if the host embryos are at the pre-blastocyst stage. We conclude that cell fate decisions within the inner cell mass are dependent upon Oct4 and that Oct4 is not cell-autonomously required for the differentiation of primitive endoderm derivatives, as long as an appropriate developmental environment is established."

	* '''Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage'''{{#pmid:20890283\|PMID20890283}} "We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA)."		* '''Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage'''{{#pmid:20890283\|PMID20890283}} "We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA)."

Z8600021 at 08:41, 5 Mayıs 2019

2019-05-05T08:41:38Z

← Older revision		Revision as of 18:41, 5 Mayıs 2019
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	:'''Links:''' {{trophoblast}} \| [http://www.ncbi.nlm.nih.gov/omim/601714 OMIM -Tead4] \| [http://www.ncbi.nlm.nih.gov/omim/600297 OMIM - Cdx2]		:'''Links:''' {{trophoblast}} \| [http://www.ncbi.nlm.nih.gov/omim/601714 OMIM -Tead4] \| [http://www.ncbi.nlm.nih.gov/omim/600297 OMIM - Cdx2]

	==Blastocoel ~~Formation~~==		==Blastocoel==
	[[File:Mouse - blastocoel formation.jpg\|thumb\|300px\|Mouse - blastocoel formation{{#pmid:19043080\|PMID19043080}}]]		[[File:Mouse - blastocoel formation.jpg\|thumb\|300px\|Mouse - blastocoel formation{{#pmid:19043080\|PMID19043080}}]]

	* trophectoderm transports of Na+ and Cl- ions through this layer into the blastocoel		* trophectoderm transports of Na+ and Cl- ions through this layer into the blastocoel
	* generates an osmotic gradient driving fluid across this epithelium		* generates an osmotic gradient driving fluid across this epithelium

Z8600021 at 03:33, 12 Mayıs 2018

2018-05-12T03:33:16Z

← Older revision		Revision as of 13:33, 12 Mayıs 2018
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	The epiblast layer will form the entire embryo and undergoes {{gastrulation}} in week three to form the 3 germ layers. It also forms an epithelial layer lining the amniotic cavity.		The epiblast layer will form the entire embryo and undergoes {{gastrulation}} in week three to form the 3 germ layers. It also forms an epithelial layer lining the amniotic cavity.

	==~~Trophoectoderm~~==		==Trophectoderm==
	The {{~~trophoectoderm~~}} (TE) outer layer of smaller cells is also called the "trophoblast" epithelium. A key early function is for the transport of sodium (Na+) and chloride (Cl-) ions through this layer into the blastocoel. Later in week 2 this layer will differentiate into two distinct {{trophoblast}} layers the {{syncytiotrophoblast}} and {{cytotrophoblast}} cells and are key to implantation and early placentation.		The {{trophectoderm}} (TE) outer layer of smaller cells is also called the "trophoblast" epithelium. A key early function is for the transport of sodium (Na+) and chloride (Cl-) ions through this layer into the blastocoel. Later in week 2 this layer will differentiate into two distinct {{trophoblast}} layers the {{syncytiotrophoblast}} and {{cytotrophoblast}} cells and are key to implantation and early placentation.


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	:'''Links:''' {{trophoblast{{ \| [http://www.ncbi.nlm.nih.gov/omim/601714 OMIM -Tead4] \| [http://www.ncbi.nlm.nih.gov/omim/600297 OMIM - Cdx2]		:'''Links:''' {{trophoblast}} \| [http://www.ncbi.nlm.nih.gov/omim/601714 OMIM -Tead4] \| [http://www.ncbi.nlm.nih.gov/omim/600297 OMIM - Cdx2]

	==Blastocoel Formation==		==Blastocoel Formation==