Anterior visceral endoderm SMAD4 signaling specifies anterior embryonic patterning and head induction in mice.

PubMed

Li, Cuiling; Li, Yi-Ping; Fu, Xin-Yuan; Deng, Chu-Xia

2010-09-27

SMAD4 serves as a common mediator for signaling of TGF-β superfamily. Previous studies illustrated that SMAD4-null mice die at embryonic day 6.5 (E6.5) due to failure of mesoderm induction and extraembryonic defects; however, functions of SMAD4 in each germ layer remain elusive. To investigate this, we disrupted SMAD4 in the visceral endoderm and epiblast, respectively, using a Cre-loxP mediated approach. We showed that mutant embryos lack of SMAD4 in the visceral endoderm (Smad4(Co/Co);TTR-Cre) died at E7.5-E9.5 without head-fold and anterior embryonic structures. We demonstrated that TGF-β regulates expression of several genes, such as Hex1, Cer1, and Lim1, in the anterior visceral endoderm (AVE), and the failure of anterior embryonic development in Smad4(Co/Co);TTR-Cre embryos is accompanied by diminished expression of these genes. Consistent with this finding, SMAD4-deficient embryoid bodies showed impaired responsiveness to TGF-β-induced gene expression and morphological changes. On the other hand, embryos carrying Cre-loxP mediated disruption of SMAD4 in the epiblasts exhibited relatively normal mesoderm and head-fold induction although they all displayed profound patterning defects in the later stages of gastrulation. Cumulatively, our data indicate that SMAD4 signaling in the epiblasts is dispensable for mesoderm induction although it remains critical for head patterning, which is significantly different from SMAD4 signaling in the AVE, where it specifies anterior embryonic patterning and head induction.

Anterior Visceral Endoderm SMAD4 Signaling Specifies Anterior Embryonic Patterning and Head Induction in Mice

PubMed Central

Li, Cuiling; Li, Yi-Ping; Fu, Xin-Yuan; Deng, Chu-Xia

2010-01-01

SMAD4 serves as a common mediator for signaling of TGF-β superfamily. Previous studies illustrated that SMAD4-null mice die at embryonic day 6.5 (E6.5) due to failure of mesoderm induction and extraembryonic defects; however, functions of SMAD4 in each germ layer remain elusive. To investigate this, we disrupted SMAD4 in the visceral endoderm and epiblast, respectively, using a Cre-loxP mediated approach. We showed that mutant embryos lack of SMAD4 in the visceral endoderm (Smad4Co/Co;TTR-Cre) died at E7.5-E9.5 without head-fold and anterior embryonic structures. We demonstrated that TGF-β regulates expression of several genes, such as Hex1, Cer1, and Lim1, in the anterior visceral endoderm (AVE), and the failure of anterior embryonic development in Smad4Co/Co;TTR-Cre embryos is accompanied by diminished expression of these genes. Consistent with this finding, SMAD4-deficient embryoid bodies showed impaired responsiveness to TGF-β-induced gene expression and morphological changes. On the other hand, embryos carrying Cre-loxP mediated disruption of SMAD4 in the epiblasts exhibited relatively normal mesoderm and head-fold induction although they all displayed profound patterning defects in the later stages of gastrulation. Cumulatively, our data indicate that SMAD4 signaling in the epiblasts is dispensable for mesoderm induction although it remains critical for head patterning, which is significantly different from SMAD4 signaling in the AVE, where it specifies anterior embryonic patterning and head induction. PMID:20941375

odd skipped related1 reveals a novel role for endoderm in regulating kidney vs. vascular cell fate

PubMed Central

Mudumana, Sudha P.; Hentschel, Dirk; Liu, Yan; Vasilyev, Aleksandr; Drummond, Iain A.

2009-01-01

Summary The kidney and vasculature are intimately linked functionally and during development, where nephric and blood/vascular progenitor cells occupy adjacent bands of mesoderm in zebrafish and frog embryos. Developmental mechanisms underlying the differentiation of kidney vs. blood/vascular lineages remain unknown. The odd skipped related1 (osr1) gene encodes a zinc finger transcription factor that is expressed in the germ ring mesendoderm and subsequently in the endoderm and intermediate mesoderm, prior to the expression of definitive kidney or blood/vascular markers. Knockdown of osr1 in zebrafish embryos resulted in a complete, segment-specific loss of anterior kidney progenitors and a compensatory increase in the number of angioblast cells in the same trunk region. Histology revealed a subsequent absence of kidney tubules, enlarged cardinal vein, and expansion of the posterior venous plexus. Altered kidney vs. vascular development correlated with expanded endoderm development in osr1 knockdowns. Combined osr1 loss of function and blockade of endoderm development by knockdown of sox32/casanova rescued anterior kidney development. The results indicate that osr1 activity is required to limit endoderm differentiation from mesendoderm and, in the absence of osr1, excess endoderm alters mesoderm differentiation, shifting the balance from kidney toward vascular development. PMID:18787069

(beta)-catenin mediates the specification of endoderm cells in ascidian embryos.

PubMed

Imai, K; Takada, N; Satoh, N; Satou, Y

2000-07-01

In the present study, we addressed the role of (beta)-catenin in the specification of embryonic cells of the ascidians Ciona intestinalis and C. savignyi and obtained the following results: (1) During cleavages, (beta)-catenin accumulated in the nuclei of vegetal blastomeres, suggesting that it plays a role in the specification of endoderm. (2) Mis- and/or overexpression of (beta)-catenin induced the development of an endoderm-specific alkaline phosphatase (AP) in presumptive notochord cells and epidermis cells without affecting differentiation of primary lineage muscle cells. (3) Downregulation of (beta)-catenin induced by the overexpression of cadherin resulted in the suppression of endoderm cell differentiation. This suppression was compensated for by the differentiation of extra epidermis cells. (4) Specification of notochord cells did not take place in the absence of endoderm differentiation. Both the overexpression of (beta)-catenin in presumptive notochord cells and the downregulation of (beta)-catenin in presumptive endoderm cells led to the suppression of Brachyury gene expression, resulting in the failure of notochord specification. These results suggest that the accumulation of (beta)-catenin in the nuclei of endoderm progenitor cells is the first step in the process of ascidian endoderm specification.

Grainyhead-like 3 regulation of endothelin-1 in the pharyngeal endoderm is critical for growth and development of the craniofacial skeleton.

PubMed

Dworkin, Sebastian; Simkin, Johanna; Darido, Charbel; Partridge, Darren D; Georgy, Smitha R; Caddy, Jacinta; Wilanowski, Tomasz; Lieschke, Graham J; Doggett, Karen; Heath, Joan K; Jane, Stephen M

2014-08-01

Craniofacial development is a highly conserved process that requires complex interactions between neural crest cells (NCCs) and pharyngeal tissues derived from all three germ layers. Signals emanating from the pharyngeal endoderm drive differentiation of NCCs into craniofacial cartilage, and disruption of this process underpins several human craniofacial defects (CFD). Here, we demonstrate that morpholino (MO)-mediated knockdown in zebrafish of the highly conserved transcription factor grainyhead-like 3 (grhl3), which is selectively expressed in the pharyngeal endoderm, leads to severe hypoplasia of the lower jaw cartilages. Phylogenetic analysis of conserved grhl-binding sites in gene regulatory regions identified endothelin-1 (edn1) as a putative direct grhl3 target gene, and this was confirmed by chromatin precipitation (ChIP) assays in zebrafish embryos. Injection of sub-phenotypic concentrations of MOs targeting both grhl3 and edn1 induced jaw abnormalities, and injection of edn1 mRNA into grhl3-morphants rescued both pharyngeal expression of the downstream effectors of edn1, and jaw cartilage formation. This study sheds new light on the role of endodermal endothelin-1 in vertebrate jaw development, and highlights potential new genetic defects that could underpin human CFD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Analysis of lamprey clustered Fox genes: insight into Fox gene evolution and expression in vertebrates.

PubMed

Wotton, Karl R; Shimeld, Sebastian M

2011-12-01

In the human genome, members of the FoxC, FoxF, FoxL1, and FoxQ1 gene families are found in two paralagous clusters. One cluster contains the genes FOXQ1, FOXF2, FOXC1 and the second consists of FOXF1, FOXC2, and FOXL1. In jawed vertebrates these genes are known to be expressed in different pharyngeal tissues and all, except FoxQ1, are involved in patterning the early embryonic mesoderm. We have previously traced the evolution of this cluster in the bony vertebrates, and the gene content is identical in the dogfish, a member of the most basally branching lineage of the jawed vertebrates. Here we extend these analyses to jawless vertebrates. Using genomic searches and molecular approaches we have identified homologues of these genes from lampreys. We identify two FoxC genes, two FoxF genes, two FoxQ1 genes and single FoxL1 gene. We examine the embryonic expression of one predominantly mesodermally expressed gene family, FoxC, and the endodermally expressed member of the cluster, FoxQ1. We identified FoxQ1 transcripts in the pharyngeal endoderm, while the two FoxC genes are differentially expressed in the pharyngeal mesenchyme and ectoderm. Furthermore we identify conserved expression of lamprey FoxC genes in the paraxial and intermediate mesoderms. We interpret our results through a chordate-wide comparison of expression patterns and discuss gene content in the context of theories on the evolution of the vertebrate genome. 2011 Elsevier B.V. All rights reserved.

An amphioxus nodal gene (AmphiNodal) with early symmetrical expression in the organizer and mesoderm and later asymmetrical expression associated with left-right axis formation

NASA Technical Reports Server (NTRS)

Yu, Jr-Kai; Holland, Linda Z.; Holland, Nicholas D.

2002-01-01

The full-length sequence and zygotic expression of an amphioxus nodal gene are described. Expression is first detected in the early gastrula just within the dorsal lip of the blastopore in a region of hypoblast that is probably comparable with the vertebrate Spemann's organizer. In the late gastrula and early neurula, expression remains bilaterally symmetrical, limited to paraxial mesoderm and immediately overlying regions of the neural plate. Later in the neurula stage, all neural expression disappears, and mesodermal expression disappears from the right side. All along the left side of the neurula, mesodermal expression spreads into the left side of the gut endoderm. Soon thereafter, all expression is down-regulated except near the anterior and posterior ends of the animal, where transcripts are still found in the mesoderm and endoderm on the left side. At this time, expression also begins in the ectoderm on the left side of the head, in the region where the mouth later forms. These results suggest that amphioxus and vertebrate nodal genes play evolutionarily conserved roles in establishing Spemann's organizer, patterning the mesoderm rostrocaudally and setting up the asymmetrical left-right axis of the body.

Lineage specific expression of Polycomb Group Proteins in human embryonic stem cells in vitro.

PubMed

Pethe, Prasad; Pursani, Varsha; Bhartiya, Deepa

2015-05-01

Human embryonic (hES) stem cells are an excellent model to study lineage specification and differentiation into various cell types. Differentiation necessitates repression of specific genes not required for a particular lineage. Polycomb Group (PcG) proteins are key histone modifiers, whose primary function is gene repression. PcG proteins form complexes called Polycomb Repressive Complexes (PRCs), which catalyze histone modifications such as H2AK119ub1, H3K27me3, and H3K9me3. PcG proteins play a crucial role during differentiation of stem cells. The expression of PcG transcripts during differentiation of hES cells into endoderm, mesoderm, and ectoderm lineage is yet to be shown. In-house derived hES cell line KIND1 was differentiated into endoderm, mesoderm, and ectoderm lineages; followed by characterization using RT-PCR for HNF4A, CDX2, MEF2C, TBX5, SOX1, and MAP2. qRT-PCR and western blotting was performed to compare expression of PcG transcripts and proteins across all the three lineages. We observed that cells differentiated into endoderm showed upregulation of RING1B, BMI1, EZH2, and EED transcripts. Mesoderm differentiation was characterized by significant downregulation of all PcG transcripts during later stages. BMI1 and RING1B were upregulated while EZH2, SUZ12, and EED remained low during ectoderm differentiation. Western blotting also showed distinct expression of BMI1 and EZH2 during differentiation into three germ layers. Our study shows that hES cells differentiating into endoderm, mesoderm, and ectoderm lineages show distinct PcG expression profile at transcript and protein level. © 2015 International Federation for Cell Biology.

DNA methylation restricts lineage-specific functions of transcription factor Gata4 during embryonic stem cell differentiation.

PubMed

Oda, Masaaki; Kumaki, Yuichi; Shigeta, Masaki; Jakt, Lars Martin; Matsuoka, Chisa; Yamagiwa, Akiko; Niwa, Hitoshi; Okano, Masaki

2013-06-01

DNA methylation changes dynamically during development and is essential for embryogenesis in mammals. However, how DNA methylation affects developmental gene expression and cell differentiation remains elusive. During embryogenesis, many key transcription factors are used repeatedly, triggering different outcomes depending on the cell type and developmental stage. Here, we report that DNA methylation modulates transcription-factor output in the context of cell differentiation. Using a drug-inducible Gata4 system and a mouse embryonic stem (ES) cell model of mesoderm differentiation, we examined the cellular response to Gata4 in ES and mesoderm cells. The activation of Gata4 in ES cells is known to drive their differentiation to endoderm. We show that the differentiation of wild-type ES cells into mesoderm blocks their Gata4-induced endoderm differentiation, while mesoderm cells derived from ES cells that are deficient in the DNA methyltransferases Dnmt3a and Dnmt3b can retain their response to Gata4, allowing lineage conversion from mesoderm cells to endoderm. Transcriptome analysis of the cells' response to Gata4 over time revealed groups of endoderm and mesoderm developmental genes whose expression was induced by Gata4 only when DNA methylation was lost, suggesting that DNA methylation restricts the ability of these genes to respond to Gata4, rather than controlling their transcription per se. Gata4-binding-site profiles and DNA methylation analyses suggested that DNA methylation modulates the Gata4 response through diverse mechanisms. Our data indicate that epigenetic regulation by DNA methylation functions as a heritable safeguard to prevent transcription factors from activating inappropriate downstream genes, thereby contributing to the restriction of the differentiation potential of somatic cells.

Molecular control of gut formation in the spider Parasteatoda tepidariorum.

PubMed

Feitosa, Natália Martins; Pechmann, Matthias; Schwager, Evelyn E; Tobias-Santos, Vitória; McGregor, Alistair P; Damen, Wim G M; Nunes da Fonseca, Rodrigo

2017-05-01

The development of a digestive system is an essential feature of bilaterians. Studies of the molecular control of gut formation in arthropods have been studied in detail in the fruit fly Drosophila melanogaster. However, little is known in other arthropods, especially in noninsect arthropods. To better understand the evolution of arthropod alimentary system, we investigate the molecular control of gut development in the spider Parasteatoda tepidariorum (Pt), the primary chelicerate model species for developmental studies. Orthologs of the ectodermal genes Pt-wingless (Pt-wg) and Pt-hedgehog (Pt-hh), of the endodermal genes, Pt-serpent (Pt-srp) and Pt-hepatocyte-nuclear factor-4 (Pt-hnf4) and of the mesodermal gene Pt-twist (Pt-twi) are expressed in the same germ layers during spider gut development as in D. melanogaster. Thus, our expression data suggest that the downstream molecular components involved in gut development in arthropods are conserved. However, Pt-forkhead (Pt-fkh) expression and function in spiders is considerably different from its D. melanogaster ortholog. Pt-fkh is expressed before gastrulation in a cell population that gives rise to endodermal and mesodermal precursors, suggesting a possible role for this factor in specification of both germ layers. To test this hypothesis, we knocked down Pt-fkh via RNA interference. Pt-fkh RNAi embryos not only fail to develop a proper gut, but also lack the mesodermal Pt-twi expressing cells. Thus, in spiders Pt-fkh specifies endodermal and mesodermal germ layers. We discuss the implications of these findings for the evolution and development of gut formation in Ecdysozoans. © 2017 Wiley Periodicals, Inc.

Temporally and spatially restricted expression of a gland cell gene during regeneration and in vitro transdifferentiation in the hydrozoan Podocoryne carnea.

PubMed

Baader, C D; Schuchert, P; Schmid, V; Heiermann, Reinhard; Plickert, Günter

1995-01-01

An antiserum to transdifferentiated striated muscle cells from the medusa of Podocoryne carnea was prepared and used to screen a λ gt11-expression library prepared from gonozoids of P. carnea. We isolated a cDNA clone termed Pod-EPPT with at least 63 tandem repeats of the tetrapeptide-motive glu-pro-pro-thr, named Pod-EPPT. Using Pod-EPPT as a molecular marker for head quality the morphological relationship between the two metagenic life stages of this hydroid, the polyp and the medusa, was studied. In situ hybridization demonstrated that expression of the gene corresponding is restricted to secretory cells in the endoderm of the oral hypostome region of polyps and medusae and, presumably, to progenitor cells of this type. Cells expressing Pod-EPPT could not be observed in the larval stage. During head regeneration in polyps, Pod-EPPT expression is upregulated soon after head removal in previously non-expressing cells and in newly differentiating secretory cells. This activation of a head-specific gene precedes the morphologically obvious events of head regeneration. Pod-EPPT is one of the genes that are activated during manubrium (mouth) regeneration from experimentally combined subumbrellar plate endoderm and striated muscle of the medusa.

Zebrafish hhex, nk2.1a, and pax2.1 regulate thyroid growth and differentiation downstream of Nodal-dependent transcription factors.

PubMed

Elsalini, Osama A; von Gartzen, Julia; Cramer, Matthias; Rohr, Klaus B

2003-11-01

During zebrafish development, the thyroid primordium initiates expression of molecular markers such as hhex and nk2.1a in the endoderm prior to pharynx formation. As expected for an endodermally derived organ, initiation of thyroid development depends on Nodal signalling. We find that it also depends on three downstream effectors of Nodal activity, casanova (cas), bonnie and clyde (bon), and faust (fau)/gata5. Despite their early Nodal-dependent expression in the endoderm, both hhex and nk2.1a are only required relatively late during thyroid development. In hhex and nk2.1a loss-of-function phenotypes, thyroid development is initiated and arrests only after the primordium has evaginated from the pharyngeal epithelium. Thus, like pax2.1, both hhex and nk2.1a have similarly late roles in differentiation or growth of thyroid follicular cells, and here, we show that all three genes act in parallel rather than in a single pathway. Our functional analysis suggests that these genes have similar roles as in mammalian thyroid development, albeit in a different temporal mode of organogenesis.

MiRNA-mediated regulation of cell signaling and homeostasis in the early mouse embryo.

PubMed

Pernaute, Barbara; Spruce, Thomas; Rodriguez, Tristan A; Manzanares, Miguel

2011-02-15

At the time of implantation the mouse embryo is composed of three tissues the epiblast, trophectoderm and primitive endoderm. As development progresses the epiblast goes on to form the foetus whilst the trophectoderm and primitive endoderm give rise to extra-embryonic structures with important roles in embryo patterning and nutrition. Dramatic changes in gene expression occur during early embryo development and these require regulation at different levels. miRNAs are small non coding RNAs that have emerged over the last decade as important post-transcriptional repressors of gene expression. The roles played by miRNAs during early mammalian development are only starting to be elucidated. In order to gain insight into the function of miRNAs in the different lineages of the early mouse embryo we have analysed in depth the phenotype of embryos and extra-embryonic stem cells mutant for the miRNA maturation protein Dicer. This study revealed that miRNAs are involved in regulating cell signaling and homeostasis in the early embryo. Specifically, we identified a role for miRNAs in regulating the Erk signaling pathway in the extra-embryonic endoderm, cell cycle progression in extra-embryonic tissues and apoptosis in the epiblast.

Imprinted expression in cystic embryoid bodies shows an embryonic and not an extra-embryonic pattern

PubMed Central

Kulinski, Tomasz M.; Casari, M. Rita T.; Guenzl, Philipp M.; Wenzel, Daniel; Andergassen, Daniel; Hladik, Anastasiya; Datlinger, Paul; Farlik, Matthias; Theussl, H. -Christian; Penninger, Josef M.; Knapp, Sylvia; Bock, Christoph; Barlow, Denise P.; Hudson, Quanah J.

2015-01-01

A large subset of mammalian imprinted genes show extra-embryonic lineage (EXEL) specific imprinted expression that is restricted to placental trophectoderm lineages and to visceral yolk sac endoderm (ysE). Isolated ysE provides a homogenous in vivo model of a mid-gestation extra-embryonic tissue to examine the mechanism of EXEL-specific imprinted gene silencing, but an in vitro model of ysE to facilitate more rapid and cost-effective experiments is not available. Reports indicate that ES cells differentiated into cystic embryoid bodies (EBs) contain ysE, so here we investigate if cystic EBs model ysE imprinted expression. The imprinted expression pattern of cystic EBs is shown to resemble fetal liver and not ysE. To investigate the reason for this we characterized the methylome and transcriptome of cystic EBs in comparison to fetal liver and ysE, by whole genome bisulphite sequencing and RNA-seq. Cystic EBs show a fetal liver pattern of global hypermethylation and low expression of repeats, while ysE shows global hypomethylation and high expression of IAPEz retroviral repeats, as reported for placenta. Transcriptome analysis confirmed that cystic EBs are more similar to fetal liver than ysE and express markers of early embryonic endoderm. Genome-wide analysis shows that ysE shares epigenetic and repeat expression features with placenta. Contrary to previous reports, we show that cystic EBs do not contain ysE, but are more similar to the embryonic endoderm of fetal liver. This explains why cystic EBs reproduce the imprinted expression seen in the embryo but not that seen in the ysE. PMID:25912690

Inhibition of Apoptosis Overcomes Stage-Related Compatibility Barriers to Chimera Formation in Mouse Embryos.

PubMed

Masaki, Hideki; Kato-Itoh, Megumi; Takahashi, Yusuke; Umino, Ayumi; Sato, Hideyuki; Ito, Keiichi; Yanagida, Ayaka; Nishimura, Toshinobu; Yamaguchi, Tomoyuki; Hirabayashi, Masumi; Era, Takumi; Loh, Kyle M; Wu, Sean M; Weissman, Irving L; Nakauchi, Hiromitsu

2016-11-03

Cell types more advanced in development than embryonic stem cells, such as EpiSCs, fail to contribute to chimeras when injected into pre-implantation-stage blastocysts, apparently because the injected cells undergo apoptosis. Here we show that transient promotion of cell survival through expression of the anti-apoptotic gene BCL2 enables EpiSCs and Sox17 + endoderm progenitors to integrate into blastocysts and contribute to chimeric embryos. Upon injection into blastocyst, BCL2-expressing EpiSCs contributed to all bodily tissues in chimeric animals while Sox17 + endoderm progenitors specifically contributed in a region-specific fashion to endodermal tissues. In addition, BCL2 expression enabled rat EpiSCs to contribute to mouse embryonic chimeras, thereby forming interspecies chimeras that could survive to adulthood. Our system therefore provides a method to overcome cellular compatibility issues that typically restrict chimera formation. Application of this type of approach could broaden the use of embryonic chimeras, including region-specific chimeras, for basic developmental biology research and regenerative medicine. Copyright © 2016 Elsevier Inc. All rights reserved.

MiR-375, a microRNA related to diabetes.

PubMed

Li, Xueling

2014-01-01

MiR-375 is an important small non-coding RNA that is specifically expressed in islet cells of the pancreas. miR-375 is required for normal pancreatic genesis and influences not only β-cell mass but also α-cell mass. miR-375 is also important to glucose-regulated insulin secretion through the regulation of the expression of Mtpn and Pdk1 genes. When human embryonic stem cells (hESCs) differentiate into endodermal lineages, miR-375 is highly expressed in the definitive endoderm, which suggests that miR-375 may have a distinct role in early development. miR-375 plays an important role in the complex regulatory network of pancreatic development, which could be regulated by pancreatic genes, such as NeuroD1, Ngn3, Pdx1 and Hnf6; additionally, miR-375 regulates genes related to pancreas development, cell growth and proliferation and insulin secretion genes to exert its function. Because of the special role of miR-375, it may be a potential target to treat diabetes. Antagonising miR-375 may enhance the effects of exendin-4 in patients, and controlling the expression of miR-375 could assist mature hESCs-derived β-cells. © 2013 Elsevier B.V. All rights reserved.

Identification of an intact ParaHox cluster with temporal colinearity but altered spatial colinearity in the hemichordate Ptychodera flava

PubMed Central

2013-01-01

Background ParaHox and Hox genes are thought to have evolved from a common ancestral ProtoHox cluster or from tandem duplication prior to the divergence of cnidarians and bilaterians. Similar to Hox clusters, chordate ParaHox genes including Gsx, Xlox, and Cdx, are clustered and their expression exhibits temporal and spatial colinearity. In non-chordate animals, however, studies on the genomic organization of ParaHox genes are limited to only a few animal taxa. Hemichordates, such as the Enteropneust acorn worms, have been used to gain insights into the origins of chordate characters. In this study, we investigated the genomic organization and expression of ParaHox genes in the indirect developing hemichordate acorn worm Ptychodera flava. Results We found that P. flava contains an intact ParaHox cluster with a similar arrangement to that of chordates. The temporal expression order of the P. flava ParaHox genes is the same as that of the chordate ParaHox genes. During embryogenesis, the spatial expression pattern of PfCdx in the posterior endoderm represents a conserved feature similar to the expression of its orthologs in other animals. On the other hand, PfXlox and PfGsx show a novel expression pattern in the blastopore. Nevertheless, during metamorphosis, PfXlox and PfCdx are expressed in the endoderm in a spatially staggered pattern similar to the situation in chordates. Conclusions Our study shows that P. flava ParaHox genes, despite forming an intact cluster, exhibit temporal colinearity but lose spatial colinearity during embryogenesis. During metamorphosis, partial spatial colinearity is retained in the transforming larva. These results strongly suggest that intact ParaHox gene clustering was retained in the deuterostome ancestor and is correlated with temporal colinearity. PMID:23802544

Gastrulation and pre-gastrulation morphogenesis, inductions, and gene expression: similarities and dissimilarities between urodelean and anuran embryos.

PubMed

Kaneda, Teruo; Motoki, Jun-ya Doi

2012-09-01

Studies of meso-endoderm and neural induction and subsequent body plan formation have been analyzed using mainly amphibians as the experimental model. Xenopus is currently the predominant model, because it best enables molecular analysis of these induction processes. However, much of the embryological information on these inductions (e.g., those of the Spemann-Mangold organizer), and on the morphogenetic movements of inductively interacting tissues, derives from research on non-model amphibians, especially urodeles. Although the final body pattern is strongly conserved in vertebrates, and although many of the same developmental genes are expressed, it has become evident that there are individually diverse modes of morphogenesis and timing of developmental events. Whether or not this diversity represents essential differences in the early induction processes remains unclear. The aim of this review is to compare the gastrulation process, induction processes, and gene expressions between a urodele, mainly Cynops pyrrhogaster, and an anura, Xenopus laevis, thereby to clarify conserved and diversified aspects. Cynops gastrulation differs significantly from that of Xenopus in that specification of the regions of the Xenopus dorsal marginal zone (DMZ) are specified before the onset of gastrulation, as marked by blastopore formation, whereas the equivalent state of specification does not occur in Cynops until the middle of gastrulation. Detailed comparison of the germ layer structure and morphogenetic movements during the pre-gastrula and gastrula stages shows that the entire gastrulation process should be divided into two phases of notochord induction and neural induction. Cynops undergoes these processes sequentially after the onset of gastrulation, whereas Xenopus undergoes notochord induction during a series of pre-gastrulation movements, and its traditionally defined period of gastrulation only includes the neural induction phase. Comparing the structure, fate, function and state of commitment of each domain of the DMZ of Xenopus and Cynops has revealed that the true form of the Spemann-Mangold organizer is suprablastoporal gsc-expressing endoderm that has notochord-inducing activity. Gsc-expressing deep endoderm and/or superficial endoderm in Xenopus is involved in inducing notochord during pre-gastrulation morphogenesis, rather than both gsc- and bra-expressing tissues being induced at the same time. Copyright © 2012 Elsevier Inc. All rights reserved.

Differential Patterning of Genes Involved in Serotonin Metabolism and Transport in Extra-embryonic Tissues of the Mouse

PubMed Central

Wu, Hsiao-Huei; Choi, Sera; Levitt, Pat

2016-01-01

Introduction Serotonin (5-HT) is an important neuromodulator, but recently has been shown to be involved in neurodevelopment. Although previous studies have demonstrated that the placenta is a major source of forebrain 5-HT during early forebrain development, the processes of how 5-HT production, metabolism, and transport from placenta to fetus are regulated are unknown. As an initial step in determining the mechanisms involved, we investigated the expression patterns of genes critical for 5-HT system function in mouse extraembryonic tissues. Methods Mid- through late gestation expression of 5-HT system-related enzymes, Tph1, Ddc, Maoa, and 5-HT transporters, Sert/Slc6a4, Oct3/Slc22a3, Vmat2/Slc18a2, and 5-HT in placenta and yolk sac were examined, with cell type-specific resolution, using multiplex fluorescent in situ hybridization to co-localize transcripts and immunocytochemistry to co-localize the corresponding proteins and neurotransmitter. Results Tph1 and Ddc are found in the syncytiotrophoblast I (SynT-I) and sinusoidal trophoblast giant cells (S-TGC), whereas Maoa is expressed in SynT-I, syncytiotrophoblast II (SynT-II) and S-TGC. Oct3 expression is observed in the SynT-II only, while Vmat2 is mainly expressed in S-TGC. Surprisingly, there were comparatively high expression of Tph1, Ddc, and Maoa in the yolk sac visceral endoderm. Discussion In addition to trophoblast cells, visceral endoderm cells in the yolk sac may contribute to fetal 5-HT production. The findings raise the possibility of a more complex regulation of 5-HT access to the fetus through the differential roles of trophoblasts that surround maternal and fetal blood space and of yolk sac endoderm prior to normal degeneration. PMID:27238716

The involvement of J-protein AtDjC17 in root development in Arabidopsis

PubMed Central

Petti, Carloalberto; Nair, Meera; DeBolt, Seth

2014-01-01

In a screen for root hair morphogenesis mutants in Arabidopsis thaliana L. we identified a T-DNA insertion within a type III J-protein AtDjC17 caused altered root hair development and reduced hair length. Root hairs were observed to develop from trichoblast and atrichoblast cell files in both Atdjc17 and 35S::AtDJC17. Localization of gene expression in the root using transgenic plants expressing proAtDjC17::GUS revealed constitutive expression in stele cells. No AtDJC17 expression was observed in epidermal, endodermal, or cortical layers. To explore the contrast between gene expression in the stele and epidermal phenotype, hand cut transverse sections of Atdjc17 roots were examined showing that the endodermal and cortical cell layers displayed increased anticlinal cell divisions. Aberrant cortical cell division in Atdjc17 is proposed as causal in ectopic root hair formation via the positional cue requirement that exists between cortical and epidermal cell in hair cell fate determination. Results indicate a requirement for AtDJC17 in position-dependent cell fate determination and illustrate an intriguing requirement for molecular co-chaperone activity during root development. PMID:25339971

EGY1 plays a role in regulation of endodermal plastid size and number that are involved in ethylene-dependent gravitropism of light-grown Arabidopsis hypocotyls.

PubMed

Guo, Di; Gao, Xiaorong; Li, Hao; Zhang, Tao; Chen, Gu; Huang, Pingbo; An, Lijia; Li, Ning

2008-03-01

Egy1 was isolated as an ethylene-dependent gravitropism-deficient Arabidopsis mutant. Molecular studies reveal that EGY1 gene encodes a 59-kDa plastid-targeted metalloprotease. It is actively expressed in hypocotyl tissue and targets to endodermal and cortex plastid. Its protein level is up-regulated by both ethylene and light. CAB protein accumulation and chlorophyll level is severely reduced in hypocotyls and endodermal cells, respectively. Sucrose is able to restore the severely reduced starch and lipid contents as well as the deficient endodermal plastid size found in light-grown egy1 hypocotyls yet it fails to rescue the reduced plastid number and chlorophyll level in egy1 endodermal cells. The loss-of-function egy1 mutation results in a smaller size (1.9 +/- 0.3 microm in diameter) and less number (5 +/- 1) of plastids in endodermal cells, which are nearly 50% of the wild-type. EGY1 is specially required for the development of full-size endodermal plastid in seedlings that are grown on sucrose-free media under light. It plays a direct role in controlling the light-induced chlorophyll production, grana formation and plastid replication in endodermal cell. However, it plays an indirect role in regulation of endodermal plastid size. It is likely that the ethylene-dependent gravitropism-deficient phenotype of egy1 hypocotyls may result from the smaller size and less number of endodermal plastids. Gravicurvature assays performed on ethylene-insensitive mutants, etr1-1, etr2-1, ers2-1, ein4-1 and ein2-5, have clearly demonstrated the necessary role for ethylene in vigorous gravitropism of light-grown hypocotyls. The degree of ethylene-dependent gravicurvature is positively correlated with the combined state of endodermal plastid mass and number. Neither ethylene nor EGY1-regulated full-size endodermal plastid is sufficient for promotion of vigorous hypocotyl gravitropism. Presence of 4 full-size plastids per endodermal cell together with ethylene pretreatment of hypocotyls becomes sufficient to trigger vigorous gravicurvature in light-grown seedlings. A model is therefore proposed to address the role of EGY1 in regulation of endodermal plastid size and number as well as the stimulatory effect of ethylene on hypocotyl gravitropism.

Role of LOTR1 in Nutrient Transport through Organization of Spatial Distribution of Root Endodermal Barriers.

PubMed

Li, Baohai; Kamiya, Takehiro; Kalmbach, Lothar; Yamagami, Mutsumi; Yamaguchi, Katsushi; Shigenobu, Shuji; Sawa, Shinichiro; Danku, John M C; Salt, David E; Geldner, Niko; Fujiwara, Toru

2017-03-06

The formation of Casparian strips and suberin lamellae at the endodermis limits the free diffusion of nutrients and harmful substances via the apoplastic space between the soil solution and the stele in roots [1-3]. Casparian strips are ring-like lignin polymers deposited in the middle of anticlinal cell walls between endodermal cells and fill the gap between them [4-6]. Suberin lamellae are glycerolipid polymers covering the endodermal cells and likely function as a barrier to limit transmembrane movement of apoplastic solutes into the endodermal cells [7, 8]. However, the current knowledge on the formation of these two distinct endodermal barriers and their regulatory role in nutrient transport is still limited. Here, we identify an uncharacterized gene, LOTR1, essential for Casparian strip formation in Arabidopsis thaliana. The lotr1 mutants display altered localization of CASP1, an essential protein for Casparian strip formation [9], disrupted Casparian strips, ectopic suberization of endodermal cells, and low accumulation of shoot calcium (Ca). Degradation by expression of a suberin-degrading enzyme in the mutants revealed that the ectopic suberization at the endodermal cells limits Ca transport through the transmembrane pathway, thereby causing reduced Ca delivery to the shoot. Moreover, analysis of the mutants showed that suberin lamellae function as an apoplastic diffusion barrier to the stele at sites of lateral root emergence where Casparian strips are disrupted. Our findings suggest that the transmembrane pathway through unsuberized endodermal cells, rather than the sites of lateral root emergence, mediates the transport of apoplastic substances such as Ca into the xylem. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regulation of endoderm formation and left-right asymmetry by miR-92 during early zebrafish development

PubMed Central

Li, Nan; Wei, Chunyao; Olena, Abigail F.; Patton, James G.

2011-01-01

microRNAs (miRNAs) are a family of 21-23 nucleotide endogenous non-coding RNAs that post-transcriptionally regulate gene expression in a sequence-specific manner. Typically, miRNAs downregulate target genes by recognizing and recruiting protein complexes to 3′UTRs, followed by translation repression or mRNA degradation. miR-92 is a well-studied oncogene in mammalian systems. Here, using zebrafish as a model system, we uncovered a novel tissue-inductive role for miR-92 during early vertebrate development. Overexpression resulted in reduced endoderm formation during gastrulation with consequent cardia and viscera bifida. By contrast, depletion of miR-92 increased endoderm formation, which led to abnormal Kupffer's vesicle development and left-right patterning defects. Using target prediction algorithms and reporter constructs, we show that gata5 is a target of miR-92. Alteration of gata5 levels reciprocally mirrored the effects of gain and loss of function of miR-92. Moreover, genetic epistasis experiments showed that miR-92-mediated defects could be substantially suppressed by modulating gata5 levels. We propose that miR-92 is a critical regulator of endoderm formation and left-right asymmetry during early zebrafish development and provide the first evidence for a regulatory function for gata5 in the formation of Kupffer's vesicle and left-right patterning. PMID:21447552

The mouse homeobox gene, S8, is expressed during embryogenesis predominantly in mesenchyme.

PubMed

Opstelten, D J; Vogels, R; Robert, B; Kalkhoven, E; Zwartkruis, F; de Laaf, L; Destrée, O H; Deschamps, J; Lawson, K A; Meijlink, F

1991-03-01

The murine S8 gene, originally identified by Kongsuwan et al. [EMBO J. 7(1988)2131-2138] encodes a homeodomain which resembles those of the paired family. We studied the expression pattern during mid-gestation embryogenesis of S8 by in situ hybridization. Expression was detected locally in craniofacial mesenchyme, in the limb, the heart and the somites and sclerotomes all along the axis, and was absent from the central and peripheral nervous system, splanchnopleure, and endodermal derivatives. This pattern differs considerably from that of most previously described homeobox containing genes. By genetic analysis, the gene was located on chromosome 2, about 20 cM from the HOX-4 cluster.

Distinct populations of endoderm cells converge to generate the embryonic liver bud and ventral foregut tissues.

PubMed

Tremblay, Kimberly D; Zaret, Kenneth S

2005-04-01

The location and movement of mammalian gut tissue progenitors, prior to the expression of tissue-specific genes, has been unknown, but this knowledge is essential to identify transitions that lead to cell type specification. To address this, we used vital dyes to label exposed anterior endoderm cells of early somite stage mouse embryos, cultured the embryos into the tissue bud phase of development, and determined the tissue fate of the dye labeled cells. This approach was performed at three embryonic stages that are prior to, or coincident with, foregut tissue patterning (1-3 somites, 4-6 somites, and 7-10 somites). Short-term labeling experiments tracked the movement of tissue progenitor cells during foregut closure. Surprisingly, we found that two distinct types of endoderm-progenitor cells, lateral and medial, arising from three spatially separated embryonic domains, converge to generate the epithelial cells of the liver bud. Whereas the lateral endoderm-progenitors give rise to descendants that are constrained in tissue fate and position along the anterior-posterior axis of the gut, the medial gut endoderm-progenitors give rise to descendants that stream along the anterior-posterior axis at the ventral midline and contribute to multiple gut tissues. The fate map reveals extensive morphogenetic movement of progenitors prior to tissue specification, it permits a detailed analysis of endoderm tissue patterning, and it illustrates that diverse progenitor domains can give rise to individual tissue cell types.

Generation of enhanced definitive endoderm from human embryonic stem cells under an albumin/insulin-free and chemically defined condition.

PubMed

Qu, Su; Yan, Liang; Fang, Bo; Ye, Shoudong; Li, Ping; Ge, Shengyang; Wu, Jian; Qu, Di; Song, Houyan

2017-04-15

To enhance survival and generation of definitive endoderm cells from human embryonic stem cells in a simple and reproducible system. Definitive endoderm (DE) differentiation from human embryonic stem cells (hESCs) was induced under a chemical-defined condition withdrawn insulin supplement and serum albumin. We dissected influence of "alternative growth factors", WNT3A, BMP4 and bFGF in activin A-driven differentiation by detection of DE-associated genes expression and cell viability. Expression of DE-associated SOX17 and FOXA2 genes was analyzed by real time reverse transcription polymerase chain reaction (RT-PCR) and Western blot assays. Quantitative evaluation of DE efficiency was performed by flow cytometry analysis of CXCR4-expressed cell population. Cell viability during DE differentiation was analyzed by an Annexin V/PI double staining test. Supplementation with WNT3A, BMP4 or bFGF promoted DE generation in a dose- and time-dependent manner. Cell apoptosis elicited by activin A was significantly ameliorated by a cocktail with WNT3A, BMP4 and bFGF. This allowed for sustained cell viability without insulin-containing supplements, thereby indirectly improving the efficiency of DE generation. Therefore, the cocktail containing is optimal for efficient DE generation in the presence of activin A and an insulin/albumin-free condition. This optimal condition facilitates the balance between the productivity and the viability maintenance, and could be valuable for mass production of DE with minimal variation. Copyright © 2017 Elsevier Inc. All rights reserved.

Four and a Half LIM Domains 1b (Fhl1b) Is Essential for Regulating the Liver versus Pancreas Fate Decision and for β-Cell Regeneration

PubMed Central

Xu, Jin; Cui, Jiaxi; Del Campo, Aranzazu; Shin, Chong Hyun

2016-01-01

The liver and pancreas originate from overlapping embryonic regions, and single-cell lineage tracing in zebrafish has shown that Bone morphogenetic protein 2b (Bmp2b) signaling is essential for determining the fate of bipotential hepatopancreatic progenitors towards the liver or pancreas. Despite its pivotal role, the gene regulatory networks functioning downstream of Bmp2b signaling in this process are poorly understood. We have identified four and a half LIM domains 1b (fhl1b), which is primarily expressed in the prospective liver anlage, as a novel target of Bmp2b signaling. fhl1b depletion compromised liver specification and enhanced induction of pancreatic cells from endodermal progenitors. Conversely, overexpression of fhl1b favored liver specification and inhibited induction of pancreatic cells. By single-cell lineage tracing, we showed that fhl1b depletion led lateral endodermal cells, destined to become liver cells, to become pancreatic cells. Reversely, when fhl1b was overexpressed, medially located endodermal cells, fated to differentiate into pancreatic and intestinal cells, contributed to the liver by directly or indirectly modulating the discrete levels of pdx1 expression in endodermal progenitors. Moreover, loss of fhl1b increased the regenerative capacity of β-cells by increasing pdx1 and neurod expression in the hepatopancreatic ductal system. Altogether, these data reveal novel and critical functions of Fhl1b in the hepatic versus pancreatic fate decision and in β-cell regeneration. PMID:26845333

Differentiation of human foreskin fibroblast-derived induced pluripotent stem cells into hepatocyte-like cells.

PubMed

Wang, Jianjun; Zhao, Ping; Wan, Zhihong; Jin, Xueyuan; Cheng, Yongqian; Yan, Tao; Qing, Song; Ding, Ning; Xin, Shaojie

2016-10-01

The aim of this study was to investigate the differentiation potential of induced pluripotent stem cells (iPSCs) derived from human foreskin fibroblasts (HFFs) into hepatocyte-like cells (HLCs). The iPSCs were firstly induced by transduction of OCT4, SOX2, KLF4, and c-MYC into HFFs using retrovirus. Afterwards, expressions of pluripotency factors were identified by semiquantitative reverse transcription-polymerase chain reaction and immunofluorescence staining, and karyotype, embryoid, and teratoma were observed by microscope. Then, iPSCs were gradually differentiated into endoderm cells, hepatic progenitor cells, and mature HLCs by special culture medium. During this process, differentiation efficiency into each kind of cells was evaluated by detecting SOX17, HNF4a, and ALB using flow cytometry, respectively. Besides, enzyme-linked immunosorbent assay was conducted to detect the secretion of ALB in iPSC-induced HLCs and quantitative reverse transcription-polymerase chain reaction was performed to detect the expression levels of hepatocyte-specific genes. The iPSCs were successfully induced by HFFs, which exhibited typical embryonic stem cells morphology, positive alkaline phosphatase staining, normal diploid karyotype, and positive expression of various pluripotency factors. Meanwhile, spherical embryoid and teratoma with 3 germ layers were formed by iPSCs. The iPSCs were consecutively induced into endoderm cells, hepatic progenitor cells and mature HLCs, and the differentiation efficiency was 55.7 ± 2.9%, 45.7 ± 4.8%, and 35.0 ± 3.9%, respectively. Besides, the secretion of ALB and expression of various hepatocyte-specific genes was highly detected in iPSC-induced HLCs. The iPSCs were successfully derived from HFFs and then differentiated into HLCs, which proved a new source for hepatocyte transplantation. HFFs were successfully induced into iPSCs by transduction of OCT4, SOX2, KLF4, and c-MYC. Positive expressions of various pluripotency factors were exhibited in HFFs-induced iPSCs. The iPSCs were consecutively induced into endoderm cells, hepatic progenitor cells, and mature HLCs. Various hepatocyte-specific genes were highly expressed in iPSC-induced HLCs. Copyright © 2016 John Wiley & Sons, Ltd.

Mutually exclusive signaling signatures define the hepatic and pancreatic progenitor cell lineage divergence

PubMed Central

Rodríguez-Seguel, Elisa; Mah, Nancy; Naumann, Heike; Pongrac, Igor M.; Cerdá-Esteban, Nuria; Fontaine, Jean-Fred; Wang, Yongbo; Chen, Wei; Andrade-Navarro, Miguel A.; Spagnoli, Francesca M.

2013-01-01

Understanding how distinct cell types arise from multipotent progenitor cells is a major quest in stem cell biology. The liver and pancreas share many aspects of their early development and possibly originate from a common progenitor. However, how liver and pancreas cells diverge from a common endoderm progenitor population and adopt specific fates remains elusive. Using RNA sequencing (RNA-seq), we defined the molecular identity of liver and pancreas progenitors that were isolated from the mouse embryo at two time points, spanning the period when the lineage decision is made. The integration of temporal and spatial gene expression profiles unveiled mutually exclusive signaling signatures in hepatic and pancreatic progenitors. Importantly, we identified the noncanonical Wnt pathway as a potential developmental regulator of this fate decision and capable of inducing the pancreas program in endoderm and liver cells. Our study offers an unprecedented view of gene expression programs in liver and pancreas progenitors and forms the basis for formulating lineage-reprogramming strategies to convert adult hepatic cells into pancreatic cells. PMID:24013505

Kindler syndrome protein Kindlin-1 is mainly expressed in adult tissues originating from ectoderm/endoderm.

PubMed

Zhan, Jun; Yang, Mei; Zhang, Jing; Guo, YongQing; Liu, Wei; Zhang, HongQuan

2015-05-01

Mutations of integrin-interacting protein Kindlin-1 cause Kindler syndrome and deregulation of Kindlin-1 is implicated in human cancers. The Kindlin-1-related diseases are confined in limited tissue types. However, Kindlin-1 tissue distribution and the dogma that governs Kindlin-1 expression in normal human body are elusive. This study examined Kindlin-1 expression in normal human adult organs, human and mouse embryonic organs by immunohistochemical analyses. We identified a general principle that the level of Kindlin-1 expression in tissues is tightly correlated with the corresponding germ layers from which these tissues originate. We compared the expression of Kindlin-1 with Kindlin-2 and found that Kindlin-1 is highly expressed in epithelial tissues derived from ectoderm and endoderm, whereas Kindlin-2 is mainly expressed in mesoderm-derived tissues. Likewise, Kindlin-1 was also found highly expressed in endoderm/ectoderm-derived tissues in human and mouse embryos. Our findings indicate that Kindlin-1 may play an importance role in the development of endoderm/ectoderm related tissues.

Differentiation of embryonic stem cells into hepatocytes that coexpress coagulation factors VIII and IX.

PubMed

Cao, Jun; Shang, Chang-zhen; Lü, Li-hong; Qiu, De-chuan; Ren, Meng; Chen, Ya-jin; Min, Jun

2010-11-01

To establish an efficient culture system to support embryonic stem (ES) cell differentiation into hepatocytes that coexpress F-VIII and F-IX. Mouse E14 ES cells were cultured in differentiation medium containing sodium butyrate (SB), basic fibroblast growth factor (bFGF), and/or bone morphogenetic protein 4 (BMP4) to induce the differentiation of endoderm cells and hepatic progenitor cells. Hepatocyte growth factor, oncostatin M, and dexamethasone were then used to induce the maturation of ES cell-derived hepatocytes. The mRNA expression levels of endoderm-specific genes and hepatocyte-specific genes, including the levels of F-VIII and F-IX, were detected by RT-PCR and real-time PCR during various stages of differentiation. Protein expression was examined by immunofluorescence and Western blot. At the final stage of differentiation, flow cytometry was performed to determine the percentage of cells coexpressing F-VIII and F-IX, and ELISA was used to detect the levels of F-VIII and F-IX protein secreted into the culture medium. The expression of endoderm-specific and hepatocyte-specific markers was upregulated to highest level in response to the combination of SB, bFGF, and BMP4. Treatment with the three inducers during hepatic progenitor differentiation significantly enhanced the mRNA and protein levels of F-VIII and F-IX in ES cell-derived hepatocytes. More importantly, F-VIII and F-IX were coexpressed with high efficiency at the final stage of differentiation, and they were also secreted into the culture medium. We have established a novel in vitro differentiation protocol for ES-derived hepatocytes that coexpress F-VIII and F-IX that may provide a foundation for stem cell replacement therapy for hemophilia.

Spatial expression of Hox cluster genes in the ontogeny of a sea urchin

NASA Technical Reports Server (NTRS)

Arenas-Mena, C.; Cameron, A. R.; Davidson, E. H.

2000-01-01

The Hox cluster of the sea urchin Strongylocentrous purpuratus contains ten genes in a 500 kb span of the genome. Only two of these genes are expressed during embryogenesis, while all of eight genes tested are expressed during development of the adult body plan in the larval stage. We report the spatial expression during larval development of the five 'posterior' genes of the cluster: SpHox7, SpHox8, SpHox9/10, SpHox11/13a and SpHox11/13b. The five genes exhibit a dynamic, largely mesodermal program of expression. Only SpHox7 displays extensive expression within the pentameral rudiment itself. A spatially sequential and colinear arrangement of expression domains is found in the somatocoels, the paired posterior mesodermal structures that will become the adult perivisceral coeloms. No such sequential expression pattern is observed in endodermal, epidermal or neural tissues of either the larva or the presumptive juvenile sea urchin. The spatial expression patterns of the Hox genes illuminate the evolutionary process by which the pentameral echinoderm body plan emerged from a bilateral ancestor.

Single-cell RNA sequencing reveals metallothionein heterogeneity during hESC differentiation to definitive endoderm.

PubMed

Lu, Junjie; Baccei, Anna; Lummertz da Rocha, Edroaldo; Guillermier, Christelle; McManus, Sean; Finney, Lydia A; Zhang, Cheng; Steinhauser, Matthew L; Li, Hu; Lerou, Paul H

2018-04-01

Differentiation of human pluripotent stem cells towards definitive endoderm (DE) is the critical first step for generating cells comprising organs such as the gut, liver, pancreas and lung. This in-vitro differentiation process generates a heterogeneous population with a proportion of cells failing to differentiate properly and maintaining expression of pluripotency factors such as Oct4. RNA sequencing of single cells collected at four time points during a 4-day DE differentiation identified high expression of metallothionein genes in the residual Oct4-positive cells that failed to differentiate to DE. Using X-ray fluorescence microscopy and multi-isotope mass spectrometry, we discovered that high intracellular zinc level corresponds with persistent Oct4 expression and failure to differentiate. This study improves our understanding of the cellular heterogeneity during in-vitro directed differentiation and provides a valuable resource to improve DE differentiation efficiency. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Generation of monoclonal antibodies specific for cell surface molecules expressed on early mouse endoderm.

PubMed

Gadue, Paul; Gouon-Evans, Valerie; Cheng, Xin; Wandzioch, Ewa; Zaret, Kenneth S; Grompe, Markus; Streeter, Philip R; Keller, Gordon M

2009-09-01

The development of functional cell populations such as hepatocytes and pancreatic beta cells from embryonic stem cell (ESC) is dependent on the efficient induction of definitive endoderm early in the differentiation process. To monitor definitive endoderm formation in mouse ESC differentiation cultures in a quantitative fashion, we generated a reporter cell line that expresses human CD25 from the Foxa3 locus and human CD4 from the Foxa2 locus. Induction of these reporter ESCs with high concentrations of activin A led to the development of a CD25-Foxa3+CD4-Foxa2+ population within 4-5 days of culture. Isolation and characterization of this population showed that it consists predominantly of definitive endoderm that is able to undergo hepatic specification under the appropriate conditions. To develop reagents that can be used for studies on endoderm development from unmanipulated ESCs, from induced pluripotent stem cells, and from the mouse embryo, we generated monoclonal antibodies against the CD25-Foxa3+CD4-Foxa2+ population. With this approach, we identified two antibodies that react specifically with endoderm from ESC cultures and from the early embryo. The specificity of these antibodies enables one to quantitatively monitor endoderm development in ESC differentiation cultures, to study endoderm formation in the embryo, and to isolate pure populations of culture- or embryo-derived endodermal cells.

Genomic, cDNA and embryonic expression analysis of zebrafish IRF6, the gene mutated in the human oral clefting disorders Van der Woude and popliteal pterygium syndromes.

PubMed

Ben, Jin; Jabs, Ethylin Wang; Chong, Samuel S

2005-06-01

Van der Woude syndrome (VWS) and popliteal pterygium syndrome (PPS) are autosomal dominant clefting disorders recently discovered to be caused by mutations in the IRF6 (Interferon Regulatory Factor 6) gene. The IRF gene family consists of nine members encoding transcription factors that share a highly conserved helix-turn-helix DNA-binding domain and a less conserved protein-binding domain. Most IRFs regulate the expression of interferon-alpha and -beta after viral infection, but the function of IRF6 remains unknown. We have isolated a full-length zebrafish irf6 cDNA, which encodes a 492 amino acid protein that contains a Smad-IRF interaction motif and a DNA-binding domain. The zebrafish irf6 gene consists of eight exons and maps to linkage group 22 closest to marker unp1375. By in situ hybridization analysis of embryo whole-mounts and cryosections, we demonstrate that irf6 is first expressed as a maternal transcript. During gastrulation, irf6 expression was concentrated in the forerunner cells. From the bud stage to the 3-somite stage, irf6 expression was observed in the Kupffer's vesicle. No expression could be detected at the 6-somite and 10-somite stages. At the 14-somite stage, expression was detected in the otic placode. At the 17-somite stage, strong expression was also observed in the cloaca. During the pharyngula, hatch and larva periods up to 5 days post-fertilization, irf6 was expressed in the pharyngeal arches, olfactory and otic placodes, and in the epithelial cells of endoderm derived tissues. The latter tissues include the mouth, pharynx, esophagus, endodermal lining of swim bladder, liver, exocrine pancreas, and associated ducts. Overall, the zebrafish expression data are consistent with the observations of lip pits in VWS patients, as well as more recent reports of alae nasi, otitis media and sensorineural hearing loss documented in some patients.

Endoderm-specific deletion of Tbx1 reveals an FGF-independent role for Tbx1 in pharyngeal apparatus morphogenesis

PubMed Central

Jackson, Abigail; Kasah, Sahrunizam; Mansour, Suzanne L.; Morrow, Bernice; Basson, M. Albert

2015-01-01

Background The T-box transcription factor Tbx1, is essential for the normal development of multiple organ systems in the embryo. One of the most striking phenotypes in Tbx1−/− embryos is the failure of the caudal pharyngeal pouches to evaginate from the foregut endoderm. Despite considerable interest in the role of Tbx1 in development, the mechanisms whereby Tbx1 controls caudal pouch formation have remained elusive. In particular, the question as to how Tbx1 expression in the pharyngeal endoderm regulates pharyngeal pouch morphogenesis in the mouse embryo is not known. Results To address this question, we produced mouse embryos in which Tbx1 was specifically deleted from the pharyngeal endoderm and as expected, embryos failed to form caudal pharyngeal pouches. To determine the molecular mechanism, we examined expression of Fgf3 and Fgf8 ligands and downstream effectors. Although Fgf8 expression is greatly reduced in Tbx1-deficient endoderm, FGF signaling levels are unaffected. Furthermore, pouch morphogenesis is only partially perturbed by the loss of both Fgf3 and Fgf8 from the endoderm, indicating that neither are required for pouch formation. Conclusions Tbx1 deletion from the pharyngeal endoderm is sufficient to cause caudal pharyngeal arch segmentation defects by FGF-independent effectors that remain to be identified. PMID:24812002

An Ancient Gene Network Is Co-opted for Teeth on Old and New Jaws

PubMed Central

Fraser, Gareth J; Hulsey, C. Darrin; Bloomquist, Ryan F; Uyesugi, Kristine; Manley, Nancy R; Streelman, J. Todd

2009-01-01

Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Much later in evolutionary time, teleost fishes evolved a novel toothed jaw in the pharynx, the location of the first vertebrate teeth. To examine the evolutionary modularity of dentitions, we asked whether oral and pharyngeal teeth develop using common or independent gene regulatory pathways. First, we showed that tooth number is correlated on oral and pharyngeal jaws across species of cichlid fishes from Lake Malawi (East Africa), suggestive of common regulatory mechanisms for tooth initiation. Surprisingly, we found that cichlid pharyngeal dentitions develop in a region of dense hox gene expression. Thus, regulation of tooth number is conserved, despite distinct developmental environments of oral and pharyngeal jaws; pharyngeal jaws occupy hox-positive, endodermal sites, and oral jaws develop in hox-negative regions with ectodermal cell contributions. Next, we studied the expression of a dental gene network for tooth initiation, most genes of which are similarly deployed across the two disparate jaw sites. This collection of genes includes members of the ectodysplasin pathway, eda and edar, expressed identically during the patterning of oral and pharyngeal teeth. Taken together, these data suggest that pharyngeal teeth of jawless vertebrates utilized an ancient gene network before the origin of oral jaws, oral teeth, and ectodermal appendages. The first vertebrate dentition likely appeared in a hox-positive, endodermal environment and expressed a genetic program including ectodysplasin pathway genes. This ancient regulatory circuit was co-opted and modified for teeth in oral jaws of the first jawed vertebrate, and subsequently deployed as jaws enveloped teeth on novel pharyngeal jaws. Our data highlight an amazing modularity of jaws and teeth as they coevolved during the history of vertebrates. We exploit this diversity to infer a core dental gene network, common to the first tooth and all of its descendants. PMID:19215146

Essential Role of Chromatin Remodeling Protein Bptf in Early Mouse Embryos and Embryonic Stem Cells

PubMed Central

Landry, Joseph; Sharov, Alexei A.; Piao, Yulan; Sharova, Lioudmila V.; Xiao, Hua; Southon, Eileen; Matta, Jennifer; Tessarollo, Lino; Zhang, Ying E.; Ko, Minoru S. H.; Kuehn, Michael R.; Yamaguchi, Terry P.; Wu, Carl

2008-01-01

We have characterized the biological functions of the chromatin remodeling protein Bptf (Bromodomain PHD-finger Transcription Factor), the largest subunit of NURF (Nucleosome Remodeling Factor) in a mammal. Bptf mutants manifest growth defects at the post-implantation stage and are reabsorbed by E8.5. Histological analyses of lineage markers show that Bptf−/− embryos implant but fail to establish a functional distal visceral endoderm. Microarray analysis at early stages of differentiation has identified Bptf-dependent gene targets including homeobox transcriptions factors and genes essential for the development of ectoderm, mesoderm, and both definitive and visceral endoderm. Differentiation of Bptf−/− embryonic stem cell lines into embryoid bodies revealed its requirement for development of mesoderm, endoderm, and ectoderm tissue lineages, and uncovered many genes whose activation or repression are Bptf-dependent. We also provide functional and physical links between the Bptf-containing NURF complex and the Smad transcription factors. These results suggest that Bptf may co-regulate some gene targets of this pathway, which is essential for establishment of the visceral endoderm. We conclude that Bptf likely regulates genes and signaling pathways essential for the development of key tissues of the early mouse embryo. PMID:18974875

Effect of abnormal notochord delamination on hindgut development in the Adriamycin mouse model.

PubMed

Sato, Hideaki; Hajduk, Piotr; Furuta, Shigeyuki; Wakisaka, Munechika; Murphy, Paula; Puri, Prem; Kitagawa, Hiroaki

2013-11-01

Adriamycin mouse model (AMM) is a model of VACTERL anomalies. Sonic hedgehog (Shh) pathway, sourced by the notochord, is implicated of anorectal malformations. We hypothesized hindgut anomalies observed in the AMM are the result of abnormal effect of the notochord. Time-mated CBA/Ca mice received two intraperitoneal injections of Adriamycin (6 mg/kg) or saline as control on embryonic day (E) 7 and 8. Fetuses were harvested from E9 to E11, stained following whole mount in situ hybridization with labeled RNA probes to detect Shh and Fork head box F1(Foxf1) transcripts. Immunolocalization with endoderm marker Hnf3β was used to visualize morphology. Embryos were scanned by OPT to obtain 3D representations of expressions. In AMM, the notochord was abnormally displaced ventrally with attachment to the hindgut endoderm in 71 % of the specimens. In 32 % of the treated embryos abnormal hindgut ended blindly in a cystic structure, and both of types were remarked in 29 % of treated embryos. Endodermal Shh and mesenchymal Foxf1 genes expression were preserved around the hindgut cystic malformation. The delamination of the developing notochord in the AMM is disrupted, which may influence signaling mechanisms from the notochord to the hindgut resulting in abnormal patterning of the hindgut.

Global expression analysis of gene regulatory pathways during endocrine pancreatic development.

PubMed

Gu, Guoqiang; Wells, James M; Dombkowski, David; Preffer, Fred; Aronow, Bruce; Melton, Douglas A

2004-01-01

To define genetic pathways that regulate development of the endocrine pancreas, we generated transcriptional profiles of enriched cells isolated from four biologically significant stages of endocrine pancreas development: endoderm before pancreas specification, early pancreatic progenitor cells, endocrine progenitor cells and adult islets of Langerhans. These analyses implicate new signaling pathways in endocrine pancreas development, and identified sets of known and novel genes that are temporally regulated, as well as genes that spatially define developing endocrine cells from their neighbors. The differential expression of several genes from each time point was verified by RT-PCR and in situ hybridization. Moreover, we present preliminary functional evidence suggesting that one transcription factor encoding gene (Myt1), which was identified in our screen, is expressed in endocrine progenitors and may regulate alpha, beta and delta cell development. In addition to identifying new genes that regulate endocrine cell fate, this global gene expression analysis has uncovered informative biological trends that occur during endocrine differentiation.

The control of foxN2/3 expression in sea urchin embryos and its function in the skeletogenic gene regulatory network.

PubMed

Rho, Ho Kyung; McClay, David R

2011-03-01

Early development requires well-organized temporal and spatial regulation of transcription factors that are assembled into gene regulatory networks (GRNs). In the sea urchin, an endomesoderm GRN model explains much of the specification in the endoderm and mesoderm prior to gastrulation, yet some GRN connections remain incomplete. Here, we characterize FoxN2/3 in the primary mesenchyme cell (PMC) GRN state. Expression of foxN2/3 mRNA begins in micromeres at the hatched blastula stage and then is lost from micromeres at the mesenchyme blastula stage. foxN2/3 expression then shifts to the non-skeletogenic mesoderm and, later, to the endoderm. Here, we show that Pmar1, Ets1 and Tbr are necessary for activation of foxN2/3 in micromeres. The later endomesoderm expression of foxN2/3 is independent of the earlier expression of foxN2/3 in micromeres and is independent of signals from PMCs. FoxN2/3 is necessary for several steps in the formation of the larval skeleton. Early expression of genes for the skeletal matrix is dependent on FoxN2/3, but only until the mesenchyme blastula stage as foxN2/3 mRNA disappears from PMCs at that time and we assume that the protein is not abnormally long-lived. Knockdown of FoxN2/3 inhibits normal PMC ingression and foxN2/3 morphant PMCs do not organize in the blastocoel and fail to join the PMC syncytium. In addition, without FoxN2/3, the PMCs fail to repress the transfating of other mesodermal cells into the skeletogenic lineage. Thus, FoxN2/3 is necessary for normal ingression, for expression of several skeletal matrix genes, for preventing transfating and for fusion of the PMC syncytium.

Cell population structure prior to bifurcation predicts efficiency of directed differentiation in human induced pluripotent cells

PubMed Central

Bargaje, Rhishikesh; Trachana, Kalliopi; Shelton, Martin N.; McGinnis, Christopher S.; Zhou, Joseph X.; Chadick, Cora; Cook, Savannah; Cavanaugh, Christopher; Huang, Sui; Hood, Leroy

2017-01-01

Steering the differentiation of induced pluripotent stem cells (iPSCs) toward specific cell types is crucial for patient-specific disease modeling and drug testing. This effort requires the capacity to predict and control when and how multipotent progenitor cells commit to the desired cell fate. Cell fate commitment represents a critical state transition or “tipping point” at which complex systems undergo a sudden qualitative shift. To characterize such transitions during iPSC to cardiomyocyte differentiation, we analyzed the gene expression patterns of 96 developmental genes at single-cell resolution. We identified a bifurcation event early in the trajectory when a primitive streak-like cell population segregated into the mesodermal and endodermal lineages. Before this branching point, we could detect the signature of an imminent critical transition: increase in cell heterogeneity and coordination of gene expression. Correlation analysis of gene expression profiles at the tipping point indicates transcription factors that drive the state transition toward each alternative cell fate and their relationships with specific phenotypic readouts. The latter helps us to facilitate small molecule screening for differentiation efficiency. To this end, we set up an analysis of cell population structure at the tipping point after systematic variation of the protocol to bias the differentiation toward mesodermal or endodermal cell lineage. We were able to predict the proportion of cardiomyocytes many days before cells manifest the differentiated phenotype. The analysis of cell populations undergoing a critical state transition thus affords a tool to forecast cell fate outcomes and can be used to optimize differentiation protocols to obtain desired cell populations. PMID:28167799

Cell population structure prior to bifurcation predicts efficiency of directed differentiation in human induced pluripotent cells.

PubMed

Bargaje, Rhishikesh; Trachana, Kalliopi; Shelton, Martin N; McGinnis, Christopher S; Zhou, Joseph X; Chadick, Cora; Cook, Savannah; Cavanaugh, Christopher; Huang, Sui; Hood, Leroy

2017-02-28

Steering the differentiation of induced pluripotent stem cells (iPSCs) toward specific cell types is crucial for patient-specific disease modeling and drug testing. This effort requires the capacity to predict and control when and how multipotent progenitor cells commit to the desired cell fate. Cell fate commitment represents a critical state transition or "tipping point" at which complex systems undergo a sudden qualitative shift. To characterize such transitions during iPSC to cardiomyocyte differentiation, we analyzed the gene expression patterns of 96 developmental genes at single-cell resolution. We identified a bifurcation event early in the trajectory when a primitive streak-like cell population segregated into the mesodermal and endodermal lineages. Before this branching point, we could detect the signature of an imminent critical transition: increase in cell heterogeneity and coordination of gene expression. Correlation analysis of gene expression profiles at the tipping point indicates transcription factors that drive the state transition toward each alternative cell fate and their relationships with specific phenotypic readouts. The latter helps us to facilitate small molecule screening for differentiation efficiency. To this end, we set up an analysis of cell population structure at the tipping point after systematic variation of the protocol to bias the differentiation toward mesodermal or endodermal cell lineage. We were able to predict the proportion of cardiomyocytes many days before cells manifest the differentiated phenotype. The analysis of cell populations undergoing a critical state transition thus affords a tool to forecast cell fate outcomes and can be used to optimize differentiation protocols to obtain desired cell populations.

GAPTrap: A Simple Expression System for Pluripotent Stem Cells and Their Derivatives.

PubMed

Kao, Tim; Labonne, Tanya; Niclis, Jonathan C; Chaurasia, Ritu; Lokmic, Zerina; Qian, Elizabeth; Bruveris, Freya F; Howden, Sara E; Motazedian, Ali; Schiesser, Jacqueline V; Costa, Magdaline; Sourris, Koula; Ng, Elizabeth; Anderson, David; Giudice, Antonietta; Farlie, Peter; Cheung, Michael; Lamande, Shireen R; Penington, Anthony J; Parish, Clare L; Thomson, Lachlan H; Rafii, Arash; Elliott, David A; Elefanty, Andrew G; Stanley, Edouard G

2016-09-13

The ability to reliably express fluorescent reporters or other genes of interest is important for using human pluripotent stem cells (hPSCs) as a platform for investigating cell fates and gene function. We describe a simple expression system, designated GAPTrap (GT), in which reporter genes, including GFP, mCherry, mTagBFP2, luc2, Gluc, and lacZ are inserted into the GAPDH locus in hPSCs. Independent clones harboring variations of the GT vectors expressed remarkably consistent levels of the reporter gene. Differentiation experiments showed that reporter expression was reliably maintained in hematopoietic cells, cardiac mesoderm, definitive endoderm, and ventral midbrain dopaminergic neurons. Similarly, analysis of teratomas derived from GT-lacZ hPSCs showed that β-galactosidase expression was maintained in a spectrum of cell types representing derivatives of the three germ layers. Thus, the GAPTrap vectors represent a robust and straightforward tagging system that enables indelible labeling of PSCs and their differentiated derivatives. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Regulatory heterochronies and loose temporal scaling between sea star and sea urchin regulatory circuits.

PubMed

Gildor, Tsvia; Hinman, Veronica; Ben-Tabou-De-Leon, Smadar

2017-01-01

It has long been argued that heterochrony, a change in relative timing of a developmental process, is a major source of evolutionary innovation. Heterochronic changes of regulatory gene activation could be the underlying molecular mechanism driving heterochronic changes through evolution. Here, we compare the temporal expression profiles of key regulatory circuits between sea urchin and sea star, representative of two classes of Echinoderms that shared a common ancestor about 500 million years ago. The morphologies of the sea urchin and sea star embryos are largely comparable, yet, differences in certain mesodermal cell types and ectodermal patterning result in distinct larval body plans. We generated high resolution temporal profiles of 17 mesodermally-, endodermally- and ectodermally-expressed regulatory genes in the sea star, Patiria miniata, and compared these to their orthologs in the Mediterranean sea urchin, Paracentrotus lividus. We found that the maternal to zygotic transition is delayed in the sea star compared to the sea urchin, in agreement with the longer cleavage stage in the sea star. Interestingly, the order of gene activation shows the highest variation in the relatively diverged mesodermal circuit, while the correlations of expression dynamics are the highest in the strongly conserved endodermal circuit. We detected loose scaling of the developmental rates of these species and observed interspecies heterochronies within all studied regulatory circuits. Thus, after 500 million years of parallel evolution, mild heterochronies between the species are frequently observed and the tight temporal scaling observed for closely related species no longer holds.

Individual blastomeres of 16- and 32-cell mouse embryos are able to develop into foetuses and mice.

PubMed

Tarkowski, Andrzej K; Suwińska, Aneta; Czołowska, Renata; Ożdżeński, Wacław

2010-12-15

Cell and developmental studies have clarified how, by the time of implantation, the mouse embryo forms three primary cell lineages: epiblast (EPI), primitive endoderm (PE), and trophectoderm (TE). However, it still remains unknown when cells allocated to these three lineages become determined in their developmental fate. To address this question, we studied the developmental potential of single blastomeres derived from 16- and 32-cell stage embryos and supported by carrier, tetraploid blastomeres. We were able to generate singletons, identical twins, triplets, and quadruplets from individual inner and outer cells of 16-cell embryos and, sporadically, foetuses from single cells of 32-cell embryos. The use of embryos constitutively expressing GFP as the donors of single diploid blastomeres enabled us to identify their cell progeny in the constructed 2n↔4n blastocysts. We showed that the descendants of donor blastomeres were able to locate themselves in all three first cell lineages, i.e., epiblast, primitive endoderm, and trophectoderm. In addition, the application of Cdx2 and Gata4 markers for trophectoderm and primitive endoderm, respectively, showed that the expression of these two genes in the descendants of donor blastomeres was either down- or up-regulated, depending on the cell lineage they happened to occupy. Thus, our results demonstrate that up to the early blastocysts stage, the destiny of at least some blastomeres, although they have begun to express markers of different lineage, is still labile. Copyright © 2010 Elsevier Inc. All rights reserved.

New markers for tracking endoderm induction and hepatocyte differentiation from human pluripotent stem cells

PubMed Central

Holtzinger, Audrey; Streeter, Philip R.; Sarangi, Farida; Hillborn, Scott; Niapour, Maryam; Ogawa, Shinichiro; Keller, Gordon

2015-01-01

The efficient generation of hepatocytes from human pluripotent stem cells (hPSCs) requires the induction of a proper endoderm population, broadly characterized by the expression of the cell surface marker CXCR4. Strategies to identify and isolate endoderm subpopulations predisposed to the liver fate do not exist. In this study, we generated mouse monoclonal antibodies against human embryonic stem cell-derived definitive endoderm with the goal of identifying cell surface markers that can be used to track the development of this germ layer and its specification to a hepatic fate. Through this approach, we identified two endoderm-specific antibodies, HDE1 and HDE2, which stain different stages of endoderm development and distinct derivative cell types. HDE1 marks a definitive endoderm population with high hepatic potential, whereas staining of HDE2 tracks with developing hepatocyte progenitors and hepatocytes. When used in combination, the staining patterns of these antibodies enable one to optimize endoderm induction and hepatic specification from any hPSC line. PMID:26493401

Intact cluster and chordate-like expression of ParaHox genes in a sea star

PubMed Central

2013-01-01

Background The ParaHox genes are thought to be major players in patterning the gut of several bilaterian taxa. Though this is a fundamental role that these transcription factors play, their activities are not limited to the endoderm and extend to both ectodermal and mesodermal tissues. Three genes compose the ParaHox group: Gsx, Xlox and Cdx. In some taxa (mostly chordates but to some degree also in protostomes) the three genes are arranged into a genomic cluster, in a similar fashion to what has been shown for the better-known Hox genes. Sea urchins possess the full complement of ParaHox genes but they are all dispersed throughout the genome, an arrangement that, perhaps, represented the primitive condition for all echinoderms. In order to understand the evolutionary history of this group of genes we cloned and characterized all ParaHox genes, studied their expression patterns and identified their genomic loci in a member of an earlier branching group of echinoderms, the asteroid Patiria miniata. Results We identified the three ParaHox orthologs in the genome of P. miniata. While one of them, PmGsx is provided as maternal message, with no zygotic activation afterwards, the other two, PmLox and PmCdx are expressed during embryogenesis, within restricted domains of both endoderm and ectoderm. Screening of a Patiria bacterial artificial chromosome (BAC) library led to the identification of a clone containing the three genes. The transcriptional directions of PmGsx and PmLox are opposed to that of the PmCdx gene within the cluster. Conclusions The identification of P. miniata ParaHox genes has revealed the fact that these genes are clustered in the genome, in contrast to what has been reported for echinoids. Since the presence of an intact cluster, or at least a partial cluster, has been reported in chordates and polychaetes respectively, it becomes clear that within echinoderms, sea urchins have modified the original bilaterian arrangement. Moreover, the sea star ParaHox domains of expression show chordate-like features not found in the sea urchin, confirming that the dynamics of gene expression for the respective genes and their putative regulatory interactions have clearly changed over evolutionary time within the echinoid lineage. PMID:23803323

Generation of stomach tissue from mouse embryonic stem cells.

PubMed

Noguchi, Taka-aki K; Ninomiya, Naoto; Sekine, Mari; Komazaki, Shinji; Wang, Pi-Chao; Asashima, Makoto; Kurisaki, Akira

2015-08-01

Successful pluripotent stem cell differentiation methods have been developed for several endoderm-derived cells, including hepatocytes, β-cells and intestinal cells. However, stomach lineage commitment from pluripotent stem cells has remained a challenge, and only antrum specification has been demonstrated. We established a method for stomach differentiation from embryonic stem cells by inducing mesenchymal Barx1, an essential gene for in vivo stomach specification from gut endoderm. Barx1-inducing culture conditions generated stomach primordium-like spheroids, which differentiated into mature stomach tissue cells in both the corpus and antrum by three-dimensional culture. This embryonic stem cell-derived stomach tissue (e-ST) shared a similar gene expression profile with adult stomach, and secreted pepsinogen as well as gastric acid. Furthermore, TGFA overexpression in e-ST caused hypertrophic mucus and gastric anacidity, which mimicked Ménétrier disease in vitro. Thus, in vitro stomach tissue derived from pluripotent stem cells mimics in vivo development and can be used for stomach disease models.

Required, tissue-specific roles for Fgf8 in outflow tract formation and remodeling.

PubMed

Park, Eon Joo; Ogden, Lisa A; Talbot, Amy; Evans, Sylvia; Cai, Chen-Leng; Black, Brian L; Frank, Deborah U; Moon, Anne M

2006-06-01

Fibroblast growth factor 8 (Fgf8) is a secreted signaling protein expressed in numerous temporospatial domains that are potentially relevant to cardiovascular development. However, the pathogenesis of complex cardiac and outflow tract defects observed in Fgf8-deficient mice, and the specific source(s) of Fgf8 required for outflow tract formation and subsequent remodeling are unknown. A detailed examination of the timing and location of Fgf8 production revealed previously unappreciated expression in a subset of primary heart field cells; Fgf8 is also expressed throughout the anterior heart field (AHF) mesoderm and in pharyngeal endoderm at the crescent and early somite stages. We used conditional mutagenesis to examine the requirements for Fgf8 function in these different expression domains during heart and outflow tract morphogenesis. Formation of the primary heart tube and the addition of right ventricular and outflow tract myocardium depend on autocrine Fgf8 signaling in cardiac crescent mesoderm. Loss of Fgf8 in this domain resulted in decreased expression of the Fgf8 target gene Erm, and aberrant production of Isl1 and its target Mef2c in the anterior heart field, thus linking Fgf8 signaling with transcription factor networks that regulate survival and proliferation of the anterior heart field. We further found that mesodermal- and endodermal-derived Fgf8 perform specific functions during outflow tract remodeling: mesodermal Fgf8 is required for correct alignment of the outflow tract and ventricles, whereas activity of Fgf8 emanating from pharyngeal endoderm regulates outflow tract septation. These findings provide a novel insight into how the formation and remodeling of primary and anterior heart field-derived structures rely on Fgf8 signals from discrete temporospatial domains.

Localization of Brachyury (T) in embryonic and extraembryonic tissues during mouse gastrulation.

PubMed

Inman, Kimberly E; Downs, Karen M

2006-10-01

T-box gene family members have important roles during murine embryogenesis, gastrulation, and organogenesis. Although relatively little is known about how T-box genes are regulated, published gene expression studies have revealed dynamic and specific patterns in both embryonic and extraembryonic tissues of the mouse conceptus. Mutant alleles of the T-box gene Brachyury (T) have identified roles in formation of mesoderm and its derivatives, such as somites and the allantois. However, given the cell autonomous nature of T gene activity and conflicting results of gene expression studies, it has been difficult to attribute a primary function to T in normal allantoic development. We report localization of T protein by sectional immunohistochemistry in both embryonic and extraembryonic tissues during mouse gastrulation, emphasizing T localization within the allantois. T was detected in all previously reported sites within the conceptus, including the primitive streak and its derivatives, nascent embryonic mesoderm, the node and notochord, as well as notochord-associated endoderm and posterior neurectoderm. In addition, we have clarified T within the allantois, where it was first detected in the proximal midline of the late allantoic bud (approximately 7.5 days postcoitum, dpc) and persisted within an expanded midline domain until 6-somite pairs (s; approximately 8.5 dpc). Lastly, we have discovered several novel T sites, including the developing heart, visceral endoderm, extraembryonic ectoderm, and its derivative, chorionic ectoderm. Together, these data provide a unified picture of T in the mammalian conceptus, and demonstrate T's presence in unrelated cell types and tissues in highly dynamic spatiotemporal patterns in both embryonic and extraembryonic tissues.

Amyloplast movement and gravityperception in Arabidopsis endoderm

NASA Astrophysics Data System (ADS)

Tasaka, M.; Saito, T.; Morita, M. T.

Gravitropism of higher plant is a growth response regulating the orientation of organs elongation, which includes four sequential steps, the perception of gravistimulus, transduction of the physical stimulus to chemical signal, transmission of the signal, and differential cell elongation depending on the signal. To elucidate the molecular mechanism of these steps, we have isolated a number of Arabidopsis mutants with abnormal shoot gravitropic response. zig (zigzag)/sgr4(shoot gravitropism 4) shows little gravitropism in their shoots. Besides, their inflorescence stems elongate in a zigzag-fashion to bend at each node. ZIG encodes a SNARE, AtVTI11. sgr3 with reduced gravitropic response in inflorescence stems had a missense mutation in other SNARE, AtVAM3. These two SNAREs make a complex in the shoot endoderm cells that are gravity-sensing cells, suggesting that the vesicle transport from trans-Golgi network (TGN) to prevacuolar compartment (PVC) and/or vacuole is involved in gravitropism. Abnormal vesicular/vacuolar structures were observed in several tissues of both mutants. Moreover, SGR2 encodes phospholipase A1-like protein that resides in the vacuolar membrane. Endodermis-specific expression of these genes could complement gravitropism in each mutant. In addition, amyloplasts thought to be statoliths localized abnormally in their endoderm cells. These results strongly suggest that formation and function of vacuole in the endoderm cells are important for amyloplasts sedimentation, which is involved in the early process of shoot gravitropism. To reveal this, we constructed vertical stage microscope system to visualize the behavior of amyloplasts and vacuolar membrane in living endodermal cells. We hope to discuss the mechanism of gravity perception after showing their movements.

Generation of Gastrointestinal Organoids from Human Pluripotent Stem Cells.

PubMed

Múnera, Jorge O; Wells, James M

2017-01-01

Over the past several decades, developmental biologists have discovered fundamental mechanisms by which organs form in developing embryos. With this information it is now possible to generate human "organoids" by the stepwise differentiation of human pluripotent stem cells using a process that recapitulates organ development. For the gastrointestinal tract, one of the first key steps is the formation of definitive endoderm and mesoderm, a process that relies on the TGFb molecule Nodal. Endoderm is then patterned along the anterior-posterior axis, with anterior endoderm forming the foregut and posterior endoderm forming the mid and hindgut. A-P patterning of the endoderm is accomplished by the combined activities of Wnt, BMP, and FGF. High Wnt and BMP promote a posterior fate, whereas repressing these pathways promotes an anterior endoderm fate. The stomach derives from the posterior foregut and retinoic acid signaling is required for promoting a posterior foregut fate. The small and large intestine derive from the mid and hindgut, respectively.These stages of gastrointestinal development can be precisely manipulated through the temporal activation and repression of the pathways mentioned above. For example, stimulation of the Nodal pathway with the mimetic Activin A, another TGF-β superfamily member, can trigger the differentiation of pluripotent stem cells into definitive endoderm (D'Amour et al., Nat Biotechnol 23:1534-1541, 2005). Exposure of definitive endoderm to high levels of Wnt and FGF promotes the formation of posterior endoderm and mid/hindgut tissue that expresses CDX2. Mid-hindgut spheroids that are cultured in a three-dimensional matrix form human intestinal organoids (HIOs) that are small intestinal in nature Spence et al., Nature 2011. In contrast, activation of FGF and Wnt in the presence of the BMP inhibitor Noggin promotes the formation of anterior endoderm and foregut tissues that express SOX2. These SOX2-expressing foregut spheroids can be further patterned into posterior foregut by addition of retinoic acid. Once formed, these posterior foregut spheroids can be grown in three-dimensional human gastric organoids (HGOs) that have all of the cell types of antral part of the stomach (Mc Cracken et al. 2014).Here, we describe the detailed methods for generating stomach/human gastric organoids (HGOs) and human intestinal organoids (HIOs) from human pluripotent stem cells. We first present a method for generating definitive endoderm from pluripotent stem cells followed by differentiation of definitive endoderm into either posterior foregut spheroids or mid-hindgut spheroids. We then describe how three-dimensional culturing of these spheroids results in the formation of HGOs and HIOs, respectively.

A Strategy To Isolate Modifiers of Caenorhabditis elegans Lethal Mutations: Investigating the Endoderm Specifying Ability of the Intestinal Differentiation GATA Factor ELT-2.

PubMed

Wiesenfahrt, Tobias; Duanmu, Jingjie; Snider, Frances; Moerman, Don; Au, Vinci; Li-Leger, Erica; Flibotte, Stephane; Parker, Dylan M; Marshall, Craig J; Nishimura, Erin Osborne; Mains, Paul E; McGhee, James D

2018-05-04

The ELT-2 GATA factor normally functions in differentiation of the C. elegans endoderm, downstream of endoderm specification. We have previously shown that, if ELT-2 is expressed sufficiently early, it is also able to specify the endoderm and to replace all other members of the core GATA-factor transcriptional cascade (END-1, END-3, ELT-7). However, such rescue requires multiple copies (and presumably overexpression) of the end-1p :: elt-2 cDNA transgene; a single copy of the transgene does not rescue. We have made this observation the basis of a genetic screen to search for genetic modifiers that allow a single copy of the end-1p :: elt-2 cDNA transgene to rescue the lethality of the end-1 end-3 double mutant. We performed this screen on a strain that has a single copy insertion of the transgene in an end-1 end-3 background. These animals are kept alive by virtue of an extrachromosomal array containing multiple copies of the rescuing transgene; the extrachromosomal array also contains a toxin under heat shock control to counterselect for mutagenized survivors that have been able to lose the rescuing array. A screen of ∼14,000 mutagenized haploid genomes produced 17 independent surviving strains. Whole genome sequencing was performed to identify genes that incurred independent mutations in more than one surviving strain. The C. elegans gene tasp-1 was mutated in four independent strains. tasp-1 encodes the C. elegans homolog of Taspase, a threonine-aspartic acid protease that has been found, in both mammals and insects, to cleave several proteins involved in transcription, in particular MLL1/trithorax and TFIIA. A second gene, pqn-82 , was mutated in two independent strains and encodes a glutamine-asparagine rich protein. tasp-1 and pqn-82 were verified as loss-of-function modifiers of the end-1p :: elt-2 transgene by RNAi and by CRISPR/Cas9-induced mutations. In both cases, gene loss leads to modest increases in the level of ELT-2 protein in the early endoderm although ELT-2 levels do not strictly correlate with rescue. We suggest that tasp-1 and pqn-82 represent a class of genes acting in the early embryo to modulate levels of critical transcription factors or to modulate the responsiveness of critical target genes. The screen's design, rescuing lethality with an extrachromosomal transgene followed by counterselection, has a background survival rate of <10 -4 without mutagenesis and should be readily adapted to the general problem of identifying suppressors of C. elegans lethal mutations. Copyright © 2018 Wiesenfahrt et al.

Generation of Functional Human Hepatic Endoderm from Human iPS cells

PubMed Central

Sullivan, Gareth J.; Hay, David C.; Park, In-Hyun; Fletcher, Judy; Hannoun, Zara; Payne, Catherine M.; Dalgetty, Donna; Black, James R.; Ross, James A.; Samuel, Kay; Wang, Gang; Daley, George Q.; Lee, Je-Hyuk; Church, George M.; Forbes, Stuart J.; Iredale, John P.; Wilmut, Ian

2009-01-01

With the advent of induced pluripotent stem cell (iPSC) technology, it is now feasible to generate iPSCs with a defined genotype or disease state. When coupled with direct differentiation of defined lineage, such as hepatic endoderm (HE). iPSC would revolutionise the way we study human liver biology and generate efficient “off the shelf” models of human liver disease. Here we show the `proof of concept' that iPSC lines representing both male and female sexes and two ethnic origins can be differentiated to HE at efficiencies of between 70–90%, using a method mimicking a physiological condition. iPSC-derived HE exhibited hepatic morphology, and expressed the hepatic markers, Albumin and E-Cadherin as assessed by immuno-histochemistry. They also expressed alpha fetal protein (AFP), HNF4a, and a metabolic marker, Cyp7A1, demonstrating a definitive endodermal lineage differentiation. Furthermore, iPSC-derived hepatocytes produced and secreted the plasma proteins, fibrinogen, fibronectin, transthyretin (TTR) and AFP, an essential feature for functional HE. Additionally iPSC-derived HE supported both CYP1A2 and 3A4 metabolism, which is essential for drug and toxicology testing. Conclusion This work is first to demonstrate the efficient generation of hepatic endodermal lineage from human iPSC that exhibits key attributes of hepatocytes, and the potential application of iPSC-derived HE in studying human liver biology. In particular, iPSC from individuals representing highly polymorphic variants in metabolic genes and different ethnic groups will provide pharmaceutical development and toxicology studies a unique opportunity to revolutionise predictive drug toxicology assays and allow the creation of in vitro hepatic disease models. PMID:19877180

Isolation of Oct4-Expressing Extraembryonic Endoderm Precursor Cell Lines

PubMed Central

Debeb, Bisrat G.; Galat, Vasiliy; Epple-Farmer, Jessica; Iannaccone, Steve; Woodward, Wendy A.; Bader, Michael; Iannaccone, Philip; Binas, Bert

2009-01-01

Background The extraembryonic endoderm (ExEn) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recent findings suggest that the committed ExEn precursor is present already in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related epiblast precursor. All ICM cells contain Oct4, a key transcription factor that is first expressed at the morula stage. In vitro, the epiblast precursor is most closely represented by the well-characterized embryonic stem (ES) cell lines that maintain the expression of Oct4, but analogous ExEn precursor cell lines are not known and it is unclear if they would express Oct4. Methodology/Principal Findings Here we report the isolation and characterization of permanently proliferating Oct4-expressing rat cell lines (“XEN-P cell lines”), which closely resemble the ExEn precursor. We isolated the XEN-P cell lines from blastocysts and characterized them by plating and gene expression assays as well as by injection into embryos. Like ES cells, the XEN-P cells express Oct4 and SSEA1 at high levels and their growth is stimulated by leukemia inhibitory factor, but instead of the epiblast determinant Nanog, they express the ExEn determinants Gata6 and Gata4. Further, they lack markers characteristic of the more differentiated primitive/visceral and parietal ExEn stages, but exclusively differentiate into these stages in vitro and contribute to them in vivo. Conclusions/Significance Our findings (i) suggest strongly that the ExEn precursor is a self-renewable entity, (ii) indicate that active Oct4 gene expression (transcription plus translation) is part of its molecular identity, and (iii) provide an in vitro model of early ExEn differentiation. PMID:19784378

A simple and economical route to generate functional hepatocyte-like cells from hESCs and their application in evaluating alcohol induced liver damage.

PubMed

Pal, Rajarshi; Mamidi, Murali Krishna; Das, Anjan Kumar; Gupta, Pawan Kumar; Bhonde, Ramesh

2012-01-01

The in vitro derived hepatocytes from human embryonic stem cells (hESC) is a promising tool to acquire improved knowledge of the cellular and molecular events underlying early human liver development under physiological and pathological conditions. Here we report a simple two-step protocol employing conditioned medium (CM) from human hepatocellular carcinoma cell line, HepG2 to generate functional hepatocyte-like cells from hESC. Immunocytochemistry, flow cytometry, quantitative RT-PCR, and biochemical analyses revealed that the endodermal progenitors appeared as pockets in culture, and the cascade of genes associated with the formation of definitive endoderm (HNF-3β, SOX-17, DLX-5, CXCR4) was consistent and in concurrence with the up-regulation of the markers for hepatic progenitors [alpha-feto protein (AFP), HNF-4α, CK-19, albumin, alpha-1-antitrypsin (AAT)], followed by maturation into functional hepatocytes [tyrosine transferase (TAT), tryptophan-2, 3-dioxygenase (TDO), glucose 6-phosphate (G6P), CYP3A4, CYP7A1]. We witnessed that the gene expression profile during this differentiation process recapitulated in vivo liver development demonstrating a gradual down-regulation of extra embryonic endodermal markers (SOX-7, HNF-1β, SNAIL-1, LAMININ-1, CDX2), and the generated hepatic cells performed multiple liver functions. Since prenatal alcohol exposure is known to provoke irreversible abnormalities in the fetal cells and developing tissues, we exposed in vitro generated hepatocytes to ethanol (EtOH) and found that EtOH treatment not only impairs the survival and proliferation, but also induces apoptosis and perturbs differentiation of progenitor cells into hepatocytes. This disruption was accompanied by alterations in the expression of genes and proteins involved in hepatogenesis. Our results provide new insights into the wider range of destruction caused by alcohol on the dynamic process of liver organogenesis. Copyright © 2011 Wiley Periodicals, Inc.

Fox (forkhead) genes are involved in the dorso-ventral patterning of the Xenopus mesoderm.

PubMed

El-Hodiri, H; Bhatia-Dey, N; Kenyon, K; Ault, K; Dirksen, M; Jamrich, M

2001-01-01

Fox (forkhead/winged helix) genes encode a family of transcription factors that are involved in embryonic pattern formation, regulation of tissue specific gene expression and tumorigenesis. Several of them are transcribed during Xenopus embryogenesis and are important for the patterning of ectoderm, mesoderm and endoderm. We have isolated three forkhead genes that are activated during gastrulation and play an important role in the dorso-ventral patterning of the mesoderm. XFKH1 (FoxA4b), the first vertebrate forkhead gene to be implicated in embryonic pattern formation, is expressed in the Spemann-Mangold organizer region and later in the embryonic notochord. XFKH7, the Xenopus orthologue of the murine Mfh1(Foxc2), is expressed in the presomitic mesoderm, but not in the notochord or lateral plate mesoderm. Finally, XFD-13'(FoxF1b)1 is expressed in the lateral plate mesoderm, but not in the notochord or presomitic mesoderm. Expression pattern and functional experiments indicate that these three forkhead genes are involved in the dorso-ventral patterning of the mesoderm.

Identification of embryonic pancreatic genes using Xenopus DNA microarrays.

PubMed

Hayata, Tadayoshi; Blitz, Ira L; Iwata, Nahoko; Cho, Ken W Y

2009-06-01

The pancreas is both an exocrine and endocrine endodermal organ involved in digestion and glucose homeostasis. During embryogenesis, the anlagen of the pancreas arise from dorsal and ventral evaginations of the foregut that later fuse to form a single organ. To better understand the molecular genetics of early pancreas development, we sought to isolate markers that are uniquely expressed in this tissue. Microarray analysis was performed comparing dissected pancreatic buds, liver buds, and the stomach region of tadpole stage Xenopus embryos. A total of 912 genes were found to be differentially expressed between these organs during early stages of organogenesis. K-means clustering analysis predicted 120 of these genes to be specifically enriched in the pancreas. Of these, we report on the novel expression patterns of 24 genes. Our analyses implicate the involvement of previously unsuspected signaling pathways during early pancreas development. Developmental Dynamics 238:1455-1466, 2009. (c) 2009 Wiley-Liss, Inc.

Fetal bovine serum enables cardiac differentiation of human embryonic stem cells.

PubMed

Bettiol, Esther; Sartiani, Laura; Chicha, Laurie; Krause, Karl Heinz; Cerbai, Elisabetta; Jaconi, Marisa E

2007-10-01

During development, cardiac commitment within the mesoderm requires endoderm-secreted factors. Differentiation of embryonic stem cells into the three germ layers in vitro recapitulates developmental processes and can be influenced by supplements added to culture medium. Hence, we investigated the effect of fetal bovine serum (FBS) and KnockOut serum replacement (SR) on germ layers specification and cardiac differentiation of H1 human embryonic stem cells (hESC) within embryoid bodies (EB). At the time of EB formation, FBS triggered an increased apoptosis. As assessed by quantitative PCR on 4-, 10-, and 20-day-old EB, FBS promoted a faster down-regulation of pluripotency marker Oct4 and an increased expression of endodermal (Sox17, alpha-fetoprotein, AFP) and mesodermal genes (Brachyury, CSX). While neuronal and hematopoietic differentiation occurred in both supplements, spontaneously beating cardiomyocytes were only observed in FBS. Action potential (AP) morphology of hESC-derived cardiomyocytes indicated that ventricular cells were present only after 2 months of culture. However, quantification of myosin light chain 2 ventricular (mlc2v)-positive areas revealed that mlc2v-expressing cardiomyocytes could be detected already after 2 weeks of differentiation, but not in all beating clusters. In conclusion, FBS enabled cardiac differentiation of hESC, likely in an endodermal-dependent pathway. Among cardiac cells, ventricular cardiomyocytes differentiated over time, but not as the predominant cardiac cell subtype.

MED GATA factors promote robust development of the C. elegans endoderm

PubMed Central

Maduro, Morris F.; Broitman-Maduro, Gina; Choi, Hailey; Carranza, Francisco; Wu, Allison Chia-Yi; Rifkin, Scott A.

2015-01-01

The MED-1,2 GATA factors contribute to specification of E, the progenitor of the C. elegans endoderm, through the genes end-1 and end-3, and in parallel with the maternal factors SKN-1, POP-1 and PAL-1. END-1,3 activate elt-2 and elt-7 to initiate a program of intestinal development, which is maintained by positive autoregulation. Here, we advance the understanding of MED-1,2 in E specification. We find that expression of end-1 and end-3 is greatly reduced in med-1,2(−) embryos. We generated strains in which MED sites have been mutated in end-1 and end-3. Without MED input, gut specification relies primarily on POP-1 and PAL-1. 25% of embryos fail to make intestine, while those that do display abnormal numbers of gut cells due to a delayed and stochastic acquisition of intestine fate. Surviving adults exhibit phenotypes consistent with a primary defect in the intestine. Our results establish that MED-1,2 provide robustness to endoderm specification through end-1 and end-3, and reveal that gut differentiation may be more directly linked to specification than previously appreciated. The results argue against an “all-or-none” description of cell specification, and suggest that activation of tissue-specific master regulators, even when expression of these is maintained by positive autoregulation, does not guarantee proper function of differentiated cells. PMID:25959238

Characterization and expression of amphioxus ApoD gene encoding an archetype of vertebrate ApoD proteins.

PubMed

Wang, Lei; Zhang, Shicui; Liu, Zhenhui; Li, Hongyan; Wang, Yongjun; Jiang, Shengjuan

2007-01-01

Here we report a homologue of the apolipoprotein D gene (AmphiApoD) in amphioxus, Branchiostoma belcheri tsingtauense, the first such finding in a basal chordate cephalochordate. The main features of the protein predicted from AmphiApoD are characteristic of the apolipoprotein D. Phylogenetic analysis places AmphiApoD at the base of the phylogenetic tree, suggesting that AmphiApoD is the archetype of the vertebrate ApoD genes. Both whole mount in situ hybridization and Northern blotting and RT-PCR as well as in situ hybridization histochemistry reveal that AmphiApoD is expressed in tissues derived from mesoderm and endoderm including notochord and hind-gut, which contrasts with the strong expression patterns of ApoD genes in the ectodermal derivatives in mammals and birds. The expression profiles of the ApoD gene may have been changed to be expressed in the endo-mesodermal derivatives in amphioxus after the vertebrate and cephalochordate lineages diverged; alternatively, the ApoD gene may first have been expressed in the endo-mesoderm during embryogenesis in the last common ancestor of all chordates, and subsequently came to be expressed in the ectodermal derivatives of vertebrates including mammals and birds.

Expansion of mesenchymal stem cells from human pancreatic ductal epithelium.

PubMed

Seeberger, Karen L; Dufour, Jannette M; Shapiro, Andrew M James; Lakey, Jonathan R T; Rajotte, Ray V; Korbutt, Gregory S

2006-02-01

Fibroblast-like cells emerging from cultured human pancreatic endocrine and exocrine tissue have been reported. Although a thorough phenotypic characterization of these cells has not yet been carried out, these cells have been hypothesized to be contaminating fibroblasts, mesenchyme and/or possibly beta-cell progenitors. In this study, we expanded fibroblast-like cells from adult human exocrine pancreas following islet isolation and characterized these cells as mesenchymal stem cells (MSCs) based on their cell surface antigen expression and ability to differentiate into mesoderm. Analysis by flow cytometry demonstrated that pancreatic MSCs express cell surface antigens used to define MSCs isolated from bone marrow such as CD13, CD29, CD44, CD49b, CD54, CD90 and CD105. In addition, utilizing protocols used to differentiate MSCs isolated from other somatic tissues, we successfully differentiated pancreatic MSCs into: (1) osteocytes that stained positive for alkaline phosphatase, collagen, mineralization (calcification) and expressed osteocalcin, (2) adipocytes that contained lipid inclusions and expressed fatty acid binding protein 4 and (3) chondrocytes that expressed aggrecan. We also demonstrated that pancreatic MSCs are multipotent and capable of deriving cells of endodermal origin. Pancreatic MSCs were differentiated into hepatocytes that stained positive for human serum albumin and expressed endoderm and liver-specific genes such as GATA 4 and tyrosine aminotransferase. In addition, preliminary protocols used to differentiate these cells into insulin-producing cells resulted in the expression of genes necessary for islet and beta-cell development such as Pax4 and neurogenin 3. Therefore, multipotent MSCs residing within the adult exocrine pancreas could represent a progenitor cell, which when further manipulated could result in the production of functional islet beta-cells.

Regulatory states in the developmental control of gene expression.

PubMed

Peter, Isabelle S

2017-09-01

A growing body of evidence shows that gene expression in multicellular organisms is controlled by the combinatorial function of multiple transcription factors. This indicates that not the individual transcription factors or signaling molecules, but the combination of expressed regulatory molecules, the regulatory state, should be viewed as the functional unit in gene regulation. Here, I discuss the concept of the regulatory state and its proposed role in the genome-wide control of gene expression. Recent analyses of regulatory gene expression in sea urchin embryos have been instrumental for solving the genomic control of cell fate specification in this system. Some of the approaches that were used to determine the expression of regulatory states during sea urchin embryogenesis are reviewed. Significant developmental changes in regulatory state expression leading to the distinct specification of cell fates are regulated by gene regulatory network circuits. How these regulatory state transitions are encoded in the genome is illuminated using the sea urchin endoderm-mesoderms cell fate decision circuit as an example. These observations highlight the importance of considering developmental gene regulation, and the function of individual transcription factors, in the context of regulatory states. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

On a Possible Evolutionary Link of the Stomochord of Hemichordates to Pharyngeal Organs of Chordates

PubMed Central

Satoh, Noriyuki; Tagawa, Kunifumi; Lowe, Christopher J.; Yu, Jr-Kai; Kawashima, Takeshi; Takahashi, Hiroki; Ogasawara, Michio; Kirschner, Marc; Hisata, Kanako; Su, Yi-Hsien; Gerhart, John

2017-01-01

Summary As a group closely related to chordates, hemichordate acorn worms are in a key phylogenic position for addressing hypotheses of chordate origins. The stomochord of acorn worms is an anterior outgrowth of the pharynx endoderm into the proboscis. In 1886 Bateson proposed homology of this organ to the chordate notochord, crowning this animal group “hemichordates.” Although this proposal has been debated for over a century, the question still remains unresolved. Here we review recent progress related to this question. First, the developmental mode of the stomochord completely differs from that of the notochord. Second, comparison of expression profiles of genes including Brachyury, a key regulator of notochord formation in chordates, does not support the stomochord/notochord homology. Third, FoxE that is expressed in the stomochord-forming region in acorn worm juveniles is expressed in the club-shaped gland and in the endostyle of amphioxus, in the endostyle of ascidians, and in the thyroid gland of vertebrates. Based on these findings, together with the anterior endodermal location of the stomochord, we propose that the stomochord has evolutionary relatedness to chordate organs deriving from the anterior pharynx rather than to the notochord. PMID:25303744

On a possible evolutionary link of the stomochord of hemichordates to pharyngeal organs of chordates.

PubMed

Satoh, Noriyuki; Tagawa, Kunifumi; Lowe, Christopher J; Yu, Jr-Kai; Kawashima, Takeshi; Takahashi, Hiroki; Ogasawara, Michio; Kirschner, Marc; Hisata, Kanako; Su, Yi-Hsien; Gerhart, John

2014-12-01

As a group closely related to chordates, hemichordate acorn worms are in a key phylogenic position for addressing hypotheses of chordate origins. The stomochord of acorn worms is an anterior outgrowth of the pharynx endoderm into the proboscis. In 1886 Bateson proposed homology of this organ to the chordate notochord, crowning this animal group "hemichordates." Although this proposal has been debated for over a century, the question still remains unresolved. Here we review recent progress related to this question. First, the developmental mode of the stomochord completely differs from that of the notochord. Second, comparison of expression profiles of genes including Brachyury, a key regulator of notochord formation in chordates, does not support the stomochord/notochord homology. Third, FoxE that is expressed in the stomochord-forming region in acorn worm juveniles is expressed in the club-shaped gland and in the endostyle of amphioxus, in the endostyle of ascidians, and in the thyroid gland of vertebrates. Based on these findings, together with the anterior endodermal location of the stomochord, we propose that the stomochord has evolutionary relatedness to chordate organs deriving from the anterior pharynx rather than to the notochord. © 2014 Wiley Periodicals, Inc.

Brachyury downstream notochord differentiation in the ascidian embryo

PubMed Central

Takahashi, Hiroki; Hotta, Kohji; Erives, Albert; Di Gregorio, Anna; Zeller, Robert W.; Levine, Michael; Satoh, Nori

1999-01-01

The ascidian tadpole represents the most simplified chordate body plan. It contains a notochord composed of just 40 cells, but as in vertebrates Brachyury is essential for notochord differentiation. Here, we show that the misexpression of the Brachyury gene (Ci-Bra) of Ciona intestinalis is sufficient to transform endoderm into notochord. Subtractive hybridization screens were conducted to identify potential Brachyury target genes that are induced upon Ci-Bra misexpression. Of 501 independent cDNA clones that were surveyed, 38 were specifically expressed in notochord cells. These potential Ci-Bra downstream genes appear to encode a broad spectrum of divergent proteins associated with notochord formation. PMID:10385620

A framework for the establishment of a cnidarian gene regulatory network for "endomesoderm" specification: the inputs of ß-catenin/TCF signaling.

PubMed

Röttinger, Eric; Dahlin, Paul; Martindale, Mark Q

2012-01-01

Understanding the functional relationship between intracellular factors and extracellular signals is required for reconstructing gene regulatory networks (GRN) involved in complex biological processes. One of the best-studied bilaterian GRNs describes endomesoderm specification and predicts that both mesoderm and endoderm arose from a common GRN early in animal evolution. Compelling molecular, genomic, developmental, and evolutionary evidence supports the hypothesis that the bifunctional gastrodermis of the cnidarian-bilaterian ancestor is derived from the same evolutionary precursor of both endodermal and mesodermal germ layers in all other triploblastic bilaterian animals. We have begun to establish the framework of a provisional cnidarian "endomesodermal" gene regulatory network in the sea anemone, Nematostella vectensis, by using a genome-wide microarray analysis on embryos in which the canonical Wnt/ß-catenin pathway was ectopically targeted for activation by two distinct pharmaceutical agents (lithium chloride and 1-azakenpaullone) to identify potential targets of endomesoderm specification. We characterized 51 endomesodermally expressed transcription factors and signaling molecule genes (including 18 newly identified) with fine-scale temporal (qPCR) and spatial (in situ) analysis to define distinct co-expression domains within the animal plate of the embryo and clustered genes based on their earliest zygotic expression. Finally, we determined the input of the canonical Wnt/ß-catenin pathway into the cnidarian endomesodermal GRN using morpholino and mRNA overexpression experiments to show that NvTcf/canonical Wnt signaling is required to pattern both the future endomesodermal and ectodermal domains prior to gastrulation, and that both BMP and FGF (but not Notch) pathways play important roles in germ layer specification in this animal. We show both evolutionary conserved as well as profound differences in endomesodermal GRN structure compared to bilaterians that may provide fundamental insight into how GRN subcircuits have been adopted, rewired, or co-opted in various animal lineages that give rise to specialized endomesodermal cell types.

Lamin A/C Haploinsufficiency Modulates the Differentiation Potential of Mouse Embryonic Stem Cells

PubMed Central

Sehgal, Poonam; Chaturvedi, Pankaj; Kumaran, R. Ileng; Kumar, Satish; Parnaik, Veena K.

2013-01-01

Background Lamins are structural proteins that are the major determinants of nuclear architecture and play important roles in various nuclear functions including gene regulation and cell differentiation. Mutations in the human lamin A gene cause a spectrum of genetic diseases that affect specific tissues. Most available mouse models for laminopathies recapitulate disease symptoms for muscle diseases and progerias. However, loss of human lamin A/C also has highly deleterious effects on fetal development. Hence it is important to understand the impact of lamin A/C expression levels on embryonic differentiation pathways. Methodology and Principal Findings We have investigated the differentiation potential of mouse embryonic stem cells containing reduced levels of lamin A/C by detailed lineage analysis of embryoid bodies derived from these cells by in vitro culture. We initially carried out a targeted disruption of one allele of the mouse lamin A/C gene (Lmna). Undifferentiated wild-type and Lmna+/− embryonic stem cells showed similar expression of pluripotency markers and cell cycle profiles. Upon spontaneous differentiation into embryoid bodies, markers for visceral endoderm such as α-fetoprotein were highly upregulated in haploinsufficient cells. However, neuronal markers such as β-III tubulin and nestin were downregulated. Furthermore, we observed a reduction in the commitment of Lmna+/− cells into the myogenic lineage, but no discernible effects on cardiac, adipocyte or osteocyte lineages. In the next series of experiments, we derived embryonic stem cell clones expressing lamin A/C short hairpin RNA and examined their differentiation potential. These cells expressed pluripotency markers and, upon differentiation, the expression of lineage-specific markers was altered as observed with Lmna+/− embryonic stem cells. Conclusions We have observed significant effects on embryonic stem cell differentiation to visceral endoderm, neuronal and myogenic lineages upon depletion of lamin A/C. Hence our results implicate lamin A/C level as an important determinant of lineage-specific differentiation during embryonic development. PMID:23451281

Transcriptome profiling to identify ATRA-responsive genes in human iPSC-derived endoderm for high-throughput point of departure analysis (SOT Annual Meeting)

EPA Science Inventory

Toxicological tipping points occur at chemical concentrations that overwhelm a cell’s adaptive response leading to permanent effects. We focused on retinoid signaling in differentiating endoderm to identify developmental pathways for tipping point analysis. Human induced pluripot...

Id expression in amphioxus and lamprey highlights the role of gene cooption during neural crest evolution

NASA Technical Reports Server (NTRS)

Meulemans, Daniel; McCauley, David; Bronner-Fraser, Marianne

2003-01-01

Neural crest cells are unique to vertebrates and generate many of the adult structures that differentiate them from their closest invertebrate relatives, the cephalochordates. Id genes are robust markers of neural crest cells at all stages of development. We compared Id gene expression in amphioxus and lamprey to ask if cephalochordates deploy Id genes at the neural plate border and dorsal neural tube in a manner similar to vertebrates. Furthermore, we examined whether Id expression in these cells is a basal vertebrate trait or a derived feature of gnathostomes. We found that while expression of Id genes in the mesoderm and endoderm is conserved between amphioxus and vertebrates, expression in the lateral neural plate border and dorsal neural tube is a vertebrate novelty. Furthermore, expression of lamprey Id implies that recruitment of Id genes to these cells occurred very early in the vertebrate lineage. Based on expression in amphioxus we postulate that Id cooption conferred sensory cell progenitor-like properties upon the lateral neurectoderm, and pharyngeal mesoderm-like properties upon cranial neural crest. Amphioxus Id expression is also consistent with homology between the anterior neurectoderm of amphioxus and the presumptive placodal ectoderm of vertebrates. These observations support the idea that neural crest evolution was driven in large part by cooption of multipurpose transcriptional regulators from other tissues and cell types.

Genomics and expression profiles of the Hedgehog and Notch signaling pathways in sea urchin development.

PubMed

Walton, Katherine D; Croce, Jenifer C; Glenn, Thomas D; Wu, Shu-Yu; McClay, David R

2006-12-01

The Hedgehog (Hh) and Notch signal transduction pathways control a variety of developmental processes including cell fate choice, differentiation, proliferation, patterning and boundary formation. Because many components of these pathways are conserved, it was predicted and confirmed that pathway components are largely intact in the sea urchin genome. Spatial and temporal location of these pathways in the embryo, and their function in development offer added insight into their mechanistic contributions. Accordingly, all major components of both pathways were identified and annotated in the sea urchin Strongylocentrotus purpuratus genome and the embryonic expression of key components was explored. Relationships of the pathway components, and modifiers predicted from the annotation of S. purpuratus, were compared against cnidarians, arthropods, urochordates, and vertebrates. These analyses support the prediction that the pathways are highly conserved through metazoan evolution. Further, the location of these two pathways appears to be conserved among deuterostomes, and in the case of Notch at least, display similar capacities in endomesoderm gene regulatory networks. RNA expression profiles by quantitative PCR and RNA in situ hybridization reveal that Hedgehog is produced by the endoderm beginning just prior to invagination, and signals to the secondary mesenchyme-derived tissues at least until the pluteus larva stage. RNA in situ hybridization of Notch pathway members confirms that Notch functions sequentially in the vegetal-most secondary mesenchyme cells and later in the endoderm. Functional analyses in future studies will embed these pathways into the growing knowledge of gene regulatory networks that govern early specification and morphogenesis.

Generation of high-yield insulin producing cells from human bone marrow mesenchymal stem cells.

PubMed

Jafarian, Arefeh; Taghikhani, Mohammad; Abroun, Saeid; Pourpak, Zahra; Allahverdi, Amir; Soleimani, Masoud

2014-07-01

Allogenic islet transplantation is a most efficient approach for treatment of diabetes mellitus. However, the scarcity of islets and long term need for an immunosuppressant limits its application. Recently, cell replacement therapies that generate of unlimited sources of β cells have been developed to overcome these limitations. In this study we have described a stage specific differentiation protocol for the generation of insulin producing islet-like clusters from human bone marrow mesenchymal stem cells (hBM-MSCs). This specific stepwise protocol induced differentiation of hMSCs into definitive endoderm, pancreatic endoderm and pancreatic endocrine cells that expressed of sox17, foxa2, pdx1, ngn3, nkx2.2, insulin, glucagon, somatostatin, pancreatic polypeptide, and glut2 transcripts respectively. In addition, immunocytochemical analysis confirmed protein expression of the above mentioned genes. Western blot analysis discriminated insulin from proinsulin in the final differentiated cells. In derived insulin producing cells (IPCs), secreted insulin and C-peptide was in a glucose dependent manner. We have developed a protocol that generates effective high-yield human IPCs from hBM-MSCs in vitro. These finding suggest that functional IPCs generated by this procedure can be used as a cell-based approach for insulin dependent diabetes mellitus.

endodermal-amyloplast less 1 is a novel allele of SHORT-ROOT

NASA Astrophysics Data System (ADS)

Morita, Miyo T.; Saito, Chieko; Nakano, Akihiko; Tasaka, Masao

Plants can sense the direction of gravity and change the growth orientation of their organs. Arabidopsis mutants have been isolated and characterized in order to elucidate the molecular mechanisms of gravitropism. endodermal-amyloplast less 1 ( eal1) is a unique mutant that completely lacks gravitropism in inflorescence stems and exhibits reduced gravitropism in hypocotyls, whereas its roots showed normal gravitropism. Previously, it was suggested that differentiation or development of amyloplasts in shoot statocytes (endodermal cells) is affected by the eal1 mutation. Here, we have identified EAL1 as a SHORT-ROOT ( SHR) allele based on map position. Three nucleotides in the SHR coding region were deleted in the eal1 mutant, resulting in the deletion of just one amino acid. The protein encoded by the novel allele of SHR appears to have retained its function as a transcription factor since the endodermal cell layer was formed both in roots and in shoots of eal1. SCARECROW (SCR) promoter activity monitored by reporter protein expression was significantly decreased in eal1, suggesting that the activity of SHR lacking one amino acid is reduced. In addition, transcription levels of SHOOT GRAVITROPISM 5 (SGR5), which is mainly expressed in the endodermis of inflorescence stems, was markedly decreased. Together with the presence of abnormal endodermal amyloplasts in eal1, these results strongly suggest that the endodermis observed in eal1 is not sufficiently differentiated to execute shoot gravitropism.

Identification of stable reference genes in differentiating human pluripotent stem cells.

PubMed

Holmgren, Gustav; Ghosheh, Nidal; Zeng, Xianmin; Bogestål, Yalda; Sartipy, Peter; Synnergren, Jane

2015-06-01

Reference genes, often referred to as housekeeping genes (HKGs), are frequently used to normalize gene expression data based on the assumption that they are expressed at a constant level in the cells. However, several studies have shown that there may be a large variability in the gene expression levels of HKGs in various cell types. In a previous study, employing human embryonic stem cells (hESCs) subjected to spontaneous differentiation, we observed that the expression of commonly used HKG varied to a degree that rendered them inappropriate to use as reference genes under those experimental settings. Here we present a substantially extended study of the HKG signature in human pluripotent stem cells (hPSC), including nine global gene expression datasets from both hESC and human induced pluripotent stem cells, obtained during directed differentiation toward endoderm-, mesoderm-, and ectoderm derivatives. Sets of stably expressed genes were compiled, and a handful of genes (e.g., EID2, ZNF324B, CAPN10, and RABEP2) were identified as generally applicable reference genes in hPSCs across all cell lines and experimental conditions. The stability in gene expression profiles was confirmed by reverse transcription quantitative PCR analysis. Taken together, the current results suggest that differentiating hPSCs have a distinct HKG signature, which in some aspects is different from somatic cell types, and underscore the necessity to validate the stability of reference genes under the actual experimental setup used. In addition, the novel putative HKGs identified in this study can preferentially be used for normalization of gene expression data obtained from differentiating hPSCs. Copyright © 2015 the American Physiological Society.

Transcription factors Mix1 and VegT, relocalization of vegt mRNA, and conserved endoderm and dorsal specification in frogs

PubMed Central

Sudou, Norihiro; Garcés-Vásconez, Andrés; López-Latorre, María A.; Taira, Masanori

2016-01-01

Protein expression of the transcription factor genes mix1 and vegt characterized the presumptive endoderm in embryos of the frogs Engystomops randi, Epipedobates machalilla, Gastrotheca riobambae, and Eleutherodactylus coqui, as in Xenopus laevis embryos. Protein VegT was detected in the animal hemisphere of the early blastula in all frogs, and only the animal pole was VegT-negative. This finding stimulated a vegt mRNA analysis in X. laevis eggs and embryos. vegt mRNA was detected in the animal region of X. laevis eggs and early embryos, in agreement with the VegT localization observed in the analyzed frogs. Moreover, a dorso-animal relocalization of vegt mRNA occurred in the egg at fertilization. Thus, the comparative analysis indicated that vegt may participate in dorsal development besides its known roles in endoderm development, and germ-layer specification. Zygotic vegt (zvegt) mRNA was detected as a minor isoform besides the major maternal (mvegt) isoform of the X. laevis egg. In addition, α-amanitin–insensitive vegt transcripts were detected around vegetal nuclei of the blastula. Thus, accumulation of vegt mRNA around vegetal nuclei was caused by relocalization rather than new mRNA synthesis. The localization of vegt mRNA around vegetal nuclei may contribute to the identity of vegetal blastomeres. These and previously reportedly localization features of vegt mRNA and protein derive from the master role of vegt in the development of frogs. The comparative analysis indicated that the strategies for endoderm, and dorsal specification, involving vegt and mix1, have been evolutionary conserved in frogs. PMID:27140624

Sox genes in the coral Acropora millepora: divergent expression patterns reflect differences in developmental mechanisms within the Anthozoa

PubMed Central

2008-01-01

Background Sox genes encode transcription factors that function in a wide range of developmental processes across the animal kingdom. To better understand both the evolution of the Sox family and the roles of these genes in cnidarians, we are studying the Sox gene complement of the coral, Acropora millepora (Class Anthozoa). Results Based on overall domain structures and HMG box sequences, the Acropora Sox genes considered here clearly fall into four of the five major Sox classes. AmSoxC is expressed in the ectoderm during development, in cells whose morphology is consistent with their assignment as sensory neurons. The expression pattern of the Nematostella ortholog of this gene is broadly similar to that of AmSoxC, but there are subtle differences – for example, expression begins significantly earlier in Acropora than in Nematostella. During gastrulation, AmSoxBb and AmSoxB1 transcripts are detected only in the presumptive ectoderm while AmSoxE1 transcription is restricted to the presumptive endoderm, suggesting that these Sox genes might play roles in germ layer specification. A third type B Sox gene, AmSoxBa, and a Sox F gene AmSoxF also have complex and specific expression patterns during early development. Each of these genes has a clear Nematostella ortholog, but in several cases the expression pattern observed in Acropora differs significantly from that reported in Nematostella. Conclusion These differences in expression patterns between Acropora and Nematostella largely reflect fundamental differences in developmental processes, underscoring the diversity of mechanisms within the anthozoan Sub-Class Hexacorallia (Zoantharia). PMID:19014479

An endothelial cell niche induces hepatic specification through dual repression of Wnt and Notch signaling

PubMed Central

Han, Songyan; Dziedzic, Noelle; Gadue, Paul; Keller, Gordon M.; Gouon-Evans, Valerie

2012-01-01

Complex cross-talk between endoderm and the microenvironment is an absolute requirement to orchestrate hepatic specification and expansion. In the mouse, the septum transversum and cardiac mesoderm, through secreted BMPs and FGFs, respectively, instruct the adjacent ventral endoderm to become hepatic endoderm. Consecutively, endothelial cells promote expansion of the specified hepatic endoderm. Using a mouse reporter embryonic stem (ES) cell line in which hCD4 and hCD25 were targeted to the Foxa2 and Foxa3 loci, we reconstituted an in vitro culture system in which committed endoderm cells co-expressing hCD4-Foxa2 and hCD25-Foxa3 were isolated, and co-cultured with endothelial cells in the presence of BMP4 and bFGF. In this culture setting, we provide mechanistic evidence that endothelial cells function not only to promote hepatic endoderm expansion, but are also required at an earlier step for hepatic specification, at least in part through regulation of the Wnt and Notch pathways. Activation of Wnt and Notch by chemical or genetic approaches increases endoderm cell numbers but inhibits hepatic specification, and conversely, chemical inhibition of both pathways enhances hepatic specification and reduces proliferation. Using identical co-culture conditions, we defined a similar dependence of endoderm harvested from embryos on endothelial cells to support their growth and hepatic specification. Our findings (1) confirm a conserved role of Wnt repression for mouse hepatic specification, (2) uncover a novel role for Notch repression in the hepatic fate decision, and (3) demonstrate that repression of Wnt and Notch signaling in hepatic endoderm is controlled by the endothelial cell niche. PMID:21732480

EXTRA-EMBRYONIC-SPECIFIC IMPRINTED EXPRESSION IS RESTRICTED TO DEFINED LINEAGES IN THE POST-IMPLANTATION EMBRYO

PubMed Central

Hudson, Quanah J.; Seidl, Christine I.M.; Kulinski, Tomasz M.; Huang, Ru; Warczok, Katarzyna E.; Bittner, Romana; Bartolomei, Marisa S.; Barlow, Denise P.

2011-01-01

A subset of imprinted genes in the mouse have been reported to show imprinted expression that is restricted to the placenta, a short-lived extra-embryonic organ. Notably these so-called 'placental-specific' imprinted genes are expressed from both parental alleles in embryo and adult tissues. The placenta is an embryonic-derived organ that is closely associated with maternal tissue and as a consequence, maternal contamination can be mistaken for maternal-specific imprinted expression. The complexity of the placenta, which arises from multiple embryonic lineages, poses additional problems in accurately assessing allele-specific repressive epigenetic modifications in genes that also show lineage-specific silencing in this organ. These problems require that extra evidence be obtained to support the imprinted status of genes whose imprinted expression is restricted to the placenta. We show here that the extra-embryonic visceral yolk sac (VYS), a nutritive membrane surrounding the developing embryo, shows a similar 'extra-embryonic-lineage-specific' pattern of imprinted expression. We present an improved enzymatic technique for separating the bilaminar VYS and show that this pattern of imprinted expression is restricted to the endoderm layer. Finally, we show that VYS 'extra-embryonic-lineage-specific' imprinted expression is regulated by DNA methylation in a similar manner as shown for genes showing multi-lineage imprinted expression in extra-embryonic, embryonic and adult tissues. These results show that the VYS is an improved model for studying the epigenetic mechanisms regulating extra-embryonic-lineage-specific imprinted expression. PMID:21354127

Transposon tagging and the study of root development in Arabidopsis

NASA Technical Reports Server (NTRS)

Tsugeki, R.; Olson, M. L.; Fedoroff, N. V.

1998-01-01

The maize Ac-Ds transposable element family has been used as the basis of transposon mutagenesis systems that function in a variety of plants, including Arabidopsis. We have developed modified transposons and methods which simplify the detection, cloning and analysis of insertion mutations. We have identified and are analyzing two plant lines in which genes expressed either in the root cap cells or in the quiescent cells, cortex/endodermal initial cells and columella cells of the root cap have been tagged with a transposon carrying a reporter gene. A gene expressed in root cap cells tagged with an enhancer-trap Ds was isolated and its corresponding EST cDNA was identified. Nucleotide and deduced amino acid sequences of the gene show no significant similarity to other genes in the database. Genetic ablation experiments have been done by fusing a root cap-specific promoter to the diphtheria toxin A-chain gene and introducing the fusion construct into Arabidopsis plants. We find that in addition to eliminating gravitropism, root cap ablation inhibits elongation of roots by lowering root meristematic activities.

O-Fucosylation of Thrombospondin Type 1 Repeats Restricts Epithelial to Mesenchymal Transition (EMT) and Maintains Epiblast Pluripotency During Mouse Gastrulation

PubMed Central

Du, Jianguang; Takeuchi, Hideyuki; Leonhard-Melief, Christina; Shroyer, Kenneth R.; Dlugosz, Malgosia; Haltiwanger, Robert S.; Holdener, Bernadette C.

2010-01-01

Thrombospondin type 1 repeat (TSR) superfamily members regulate diverse biological activities ranging from cell motility to inhibition of angiogenesis. In this study, we verified that mouse protein O-fucosyltransferase-2 (POFUT2) specifically adds O-fucose to TSRs. Using two Pofut2 gene trap lines, we demonstrated that O-fucosylation of TSRs was essential for restricting epithelial to mesenchymal transition in the primitive streak, correct patterning of mesoderm, and localization of the definitive endoderm. Although Pofut2 mutant embryos established anterior/posterior polarity, they underwent extensive mesoderm differentiation at the expense of maintaining epiblast pluripotency. Moreover, mesoderm differentiation was biased towards the vascular endothelial cell lineage. Localization of Foxa2 and Cer1 expressing cells within the interior of Pofut2 mutant embryos suggested that POFUT2 activity was also required for the displacement of the primitive endoderm by definitive endoderm. Notably, Nodal, BMP4, Fgf8, and Wnt3 expression were markedly elevated and expanded in Pofut2 mutants, providing evidence that O-fucose modification of TSRs was essential for modulation of growth factor signaling during gastrulation. The ability of Pofut2 mutant embryos to form teratomas comprised of tissues from all three germ layer origins suggested that defects in Pofut2 mutant embryos resulted from abnormalities in the extracellular environment. This prediction is consistent with the observation that POFUT2 targets are constitutive components of the extracellular matrix (ECM) or associate with the ECM. For this reason, the Pofut2 mutants represent a valuable tool for studying the role of O-fucosylation in ECM synthesis and remodeling, and will be a valuable model to study how post-translational modification of ECM components regulates the formation of tissue boundaries, cell movements, and signaling. PMID:20637190

HOM/HOX homeobox genes are present in hydra (Chlorohydra viridissima) and are differentially expressed during regeneration.

PubMed Central

Schummer, M; Scheurlen, I; Schaller, C; Galliot, B

1992-01-01

Hydra, a diblastic animal consisting of two cell layers, ectoderm and endoderm, is one of the most ancient animals displaying an anteroposterior axis with a head and a foot developing from an uncommitted gastric region. As such, hydra is an interesting model for studying the presence and function of homeobox genes in a phylogenetically old organism. By screening a Chlorohydra viridissima cDNA library with a 'guessmer' oligonucleotide, we have cloned several such cnidarian homeobox-containing genes (cnox genes). Two of these, cnox1 and cnox2, display labial and Deformed type homeodomains respectively and could represent two ancestral genes of the HOM/HOX complexes; cnox3 exhibits some similarity to the BarH1 and the distal-less type homeodomains and a fourth gene is highly related to the msh/Hox7 type of homeodomain. We used quantitative PCR to study levels of expression of these genes along the body axis and during head regeneration. In all cases, the expression in heads was stronger than that in the gastric region. cnox1 transcripts dramatically peaked within the first hours of head regeneration, whereas cnox2 and cnox3 reached their maximal levels 1 and 2 days after cutting respectively. This differential expression of homeobox genes at various stages of regeneration suggests that they play specific roles in regenerative processes. Images PMID:1374713

Neural tube closure depends on expression of Grainyhead-like 3 in multiple tissues.

PubMed

De Castro, Sandra C P; Hirst, Caroline S; Savery, Dawn; Rolo, Ana; Lickert, Heiko; Andersen, Bogi; Copp, Andrew J; Greene, Nicholas D E

2018-03-15

Failure of neural tube closure leads to neural tube defects (NTDs), common congenital abnormalities in humans. Among the genes whose loss of function causes NTDs in mice, Grainyhead-like3 (Grhl3) is essential for spinal neural tube closure, with null mutants exhibiting fully penetrant spina bifida. During spinal neurulation Grhl3 is initially expressed in the surface (non-neural) ectoderm, subsequently in the neuroepithelial component of the neural folds and at the node-streak border, and finally in the hindgut endoderm. Here, we show that endoderm-specific knockout of Grhl3 causes late-arising spinal NTDs, preceded by increased ventral curvature of the caudal region which was shown previously to suppress closure of the spinal neural folds. This finding supports the hypothesis that diminished Grhl3 expression in the hindgut is the cause of spinal NTDs in the curly tail, carrying a hypomorphic Grhl3 allele. Complete loss of Grhl3 function produces a more severe phenotype in which closure fails earlier in neurulation, before the stage of onset of expression in the hindgut of wild-type embryos. This implicates additional tissues and NTD mechanisms in Grhl3 null embryos. Conditional knockout of Grhl3 in the neural plate and node-streak border has minimal effect on closure, suggesting that abnormal function of surface ectoderm, where Grhl3 transcripts are first detected, is primarily responsible for early failure of spinal neurulation in Grhl3 null embryos. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Diverse effects of lead nitrate on the proliferation, differentiation, and gene expression of stem cells isolated from a dental origin.

PubMed

Abdullah, Mariam; Rahman, Fazliny Abd; Gnanasegaran, Nareshwaran; Govindasamy, Vijayendran; Abu Kasim, Noor Hayaty; Musa, Sabri

2014-01-01

Lead (Pb(2+)) exposure continues to be a significant public health problem. Therefore, it is vital to have a continuous epidemiological dataset for a better understanding of Pb(2+) toxicity. In the present study, we have exposed stem cells isolated from deciduous and permanent teeth, periodontal ligament, and bone marrow to five different types of Pb(2+) concentrations (160, 80, 40, 20, and 10 µM) for 24 hours to identify the adverse effects of Pb(2+) on the proliferation, differentiation, and gene expression on these cell lines. We found that Pb(2+) treatment altered the morphology and adhesion of the cells in a dose-dependent manner. There were no significant changes in terms of cell surface phenotypes. Cells exposed to Pb(2+) continued to differentiate into chondrogenesis and adipogenesis, and a severe downregulation was observed in osteogenesis. Gene expression studies revealed a constant expression of key markers associated with stemness (Oct 4, Rex 1) and DNA repair enzyme markers, but downregulation occurred with some ectoderm and endoderm markers, demonstrating an irregular and untimely differentiation trail. Our study revealed for the first time that Pb(2+) exposure not only affects the phenotypic characteristics but also induces significant alteration in the differentiation and gene expression in the cells.

An amphioxus winged helix/forkhead gene, AmphiFoxD: insights into vertebrate neural crest evolution

NASA Technical Reports Server (NTRS)

Yu, Jr-Kai; Holland, Nicholas D.; Holland, Linda Z.

2002-01-01

During amphioxus development, the neural plate is bordered by cells expressing many genes with homologs involved in vertebrate neural crest induction. However, these amphioxus cells evidently lack additional genetic programs for the cell delaminations, migrations, and differentiations characterizing definitive vertebrate neural crest. We characterize an amphioxus winged helix/forkhead gene (AmphiFoxD) closely related to vertebrate FoxD genes. Phylogenetic analysis indicates that the AmphiFoxD is basal to vertebrate FoxD1, FoxD2, FoxD3, FoxD4, and FoxD5. One of these vertebrate genes (FoxD3) consistently marks neural crest during development. Early in amphioxus development, AmphiFoxD is expressed medially in the anterior neural plate as well as in axial (notochordal) and paraxial mesoderm; later, the gene is expressed in the somites, notochord, cerebral vesicle (diencephalon), and hindgut endoderm. However, there is never any expression in cells bordering the neural plate. We speculate that an AmphiFoxD homolog in the common ancestor of amphioxus and vertebrates was involved in histogenic processes in the mesoderm (evagination and delamination of the somites and notochord); then, in the early vertebrates, descendant paralogs of this gene began functioning in the presumptive neural crest bordering the neural plate to help make possible the delaminations and cell migrations that characterize definitive vertebrate neural crest. Copyright 2002 Wiley-Liss, Inc.

Generation and characterization of Tbx1-AmCyan1 transgenic reporter mouse line that selectively labels developing thymus primordium.

PubMed

Kimura, Wataru; Sharkar, Mohammad Tofael Kabir; Sultana, Nishat; Islam, Mohammod Johirul; Uezato, Tadayoshi; Miura, Naoyuki

2013-06-01

Thymus development is a complicated process that includes highly dynamic morphological changes and reciprocal tissue interactions between endoderm-derived epithelial cells of the anterior foregut and neural crest-derived mesenchymal cells. We generated and characterized a Tbx1-AmCyan1 reporter transgenic mouse to visualize thymus precursor cells during early embryonic development. In transgenic embryos, AmCyan1 fluorescence was specifically detected in the endoderm of the developing 3rd and 4th pharyngeal pouches and later in thymus epithelium until E14.5. Cells expressing AmCyan1 that were isolated based on AmCyan1 fluorescence expressed endodermal, thymic, and parathyroid markers, but they did not express neural crest or endothelial markers; these findings indicated that this transgenic mouse strain could be used to collect thymic or parathyroid precursor cells or both. We also showed that in nude mice, which exhibit defects in thymus development, the thymus precursors were clearly labeled with AmCyan1. In summary, these AmCyan1-fluorescent transgenic mice are useful for investigating early thymus development.

Pioneer factors, genetic competence, and inductive signaling: programming liver and pancreas progenitors from the endoderm.

PubMed

Zaret, K S; Watts, J; Xu, J; Wandzioch, E; Smale, S T; Sekiya, T

2008-01-01

The endoderm is a multipotent progenitor cell population in the embryo that gives rise to the liver, pancreas, and other cell types and provides paradigms for understanding cell-type specification. Studies of isolated embryo tissue cells and genetic approaches in vivo have defined fibroblast growth factor/mitogen-activated protein kinase (FGF/MAPK) and bone morphogenetic protein (BMP) signaling pathways that induce liver and pancreatic fates in the endoderm. In undifferentiated endoderm cells, the FoxA and GATA transcription factors are among the first to engage silent genes, helping to endow competence for cell-type specification. FoxA proteins can bind their target sites in highly compacted chromatin and open up the local region for other factors to bind; hence, they have been termed "pioneer factors." We recently found that FoxA proteins remain bound to chromatin in mitosis, as an epigenetic mark. In embryonic stem cells, which lack FoxA, FoxA target sites can be occupied by FoxD3, which in turn helps to maintain a local demethylation of chromatin. By these means, a cascade of Fox factors helps to endow progenitor cells with the competence to activate genes in response to tissue-inductive signals. Understanding such epigenetic mechanisms for transcriptional competence coupled with knowledge of the relevant signals for cell-type specification should greatly facilitate efforts to predictably differentiate stem cells to liver and pancreatic fates.

Expression of the cytokeratin endo A gene during early mouse embryogenesis.

PubMed Central

Duprey, P; Morello, D; Vasseur, M; Babinet, C; Condamine, H; Brûlet, P; Jacob, F

1985-01-01

Expression of cytokeratin endo A has been analyzed during mouse blastocyst formation and embryonal carcinoma cell differentiation. To study the regulation of endo A expression, nuclease S1 mapping experiments have been performed on RNA extracted from two-cell to 7.5-day embryos. Low levels of endo A mRNA begin to be detectable in eight-cell embryos. The amount of this mRNA increases at the blastocyst stage, suggesting that endo A expression is regulated at the mRNA level during blastocyst formation. At this stage, in situ hybridization studies show that endo A mRNA is present in the trophectoderm but not in the inner cell mass. In 7.5-day embryos, endo A mRNAs are also detectable in the endoderm layer and in the amnion. Images PMID:2417224

Fgf8 expression in the Tbx1 domain causes skeletal abnormalities and modifies the aortic arch but not the outflow tract phenotype of Tbx1 mutants

PubMed Central

Vitelli, Francesca; Zhang, Zhen; Huynh, Tuong; Sobotka, Angela; Mupo, Annalisa; Baldini, Antonio

2007-01-01

Fgf8 and Tbx1 have been shown to interact in patterning the aortic arch, and both genes are required in formation and growth of the outflow tract of the heart. However, the nature of the interaction of the two genes is unclear. We have utilized a novel Tbx1Fgf8 allele which drives Fgf8 expression in Tbx1-positive cells and an inducible Cre-LoxP recombination system to address the role of Fgf8 in Tbx1 positive cells in modulating cardiovascular development. Results support a requirement of Fgf8 in Tbx1 expressing cells to finely control patterning of the aortic arch and great arteries specifically during the pharyngeal arch artery remodeling process and indicate that the endoderm is the most likely site of this interaction. Furthermore, our data suggest that Fgf8 and Tbx1 play independent roles in regulating outflow tract development. This finding is clinically relevant since TBX1 is the candidate for DGS/VCFS, characterized clinically by variable expressivity and reduced penetrance of cardiovascular defects; Fgf8 gene variants may provide molecular clues to this variability. PMID:16696966

Characterization of Cer-1 cis-regulatory region during early Xenopus development.

PubMed

Silva, Ana Cristina; Filipe, Mário; Steinbeisser, Herbert; Belo, José António

2011-05-01

Cerberus-related molecules are well-known Wnt, Nodal, and BMP inhibitors that have been implicated in different processes including anterior–posterior patterning and left–right asymmetry. In both mouse and frog, two Cerberus-related genes have been isolated, mCer-1 and mCer-2, and Xcer and Xcoco, respectively. Until now, little is known about the mechanisms involved in their transcriptional regulation. Here, we report a heterologous analysis of the mouse Cerberus-1 gene upstream regulatory regions, responsible for its expression in the visceral endodermal cells. Our analysis showed that the consensus sequences for a TATA, CAAT, or GC boxes were absent but a TGTGG sequence was present at position -172 to -168 bp, relative to the ATG. Using a series of deletion constructs and transient expression in Xenopus embryos, we found that a fragment of 1.4 kb of Cer-1 promoter sequence could reproduce the endogenous expression pattern of Xenopus cerberus. A 0.7-kb mcer-1 upstream region was able to drive reporter expression to the involuting mesendodermal cells, while further deletions abolished reporter gene expression. Our results suggest that although no sequence similarity was found between mouse and Xenopus cerberus cis-regulatory regions, the signaling cascades regulating cerberus expression, during gastrulation, is conserved.

Involvement of the Vacuoles of the Endodermis in the Early Process of Shoot Gravitropism in Arabidopsis

PubMed Central

Morita, Miyo Terao; Kato, Takehide; Nagafusa, Kiyoshi; Saito, Chieko; Ueda, Takashi; Nakano, Akihiko; Tasaka, Masao

2002-01-01

The endodermal cells of the shoot are thought to be the gravity-sensing cells in Arabidopsis. The amyloplasts in the endodermis that sediment in the direction of gravity may act as statoliths. Endodermis-specific expression of SGR2 and ZIG using the SCR promoter could complement the abnormal shoot gravitropism of the sgr2 and zig mutants, respectively. The abnormalities in amyloplast sedimentation observed in both mutants recovered simultaneously. These results indicate that both genes in the endodermal cell layer are crucial for shoot gravitropism. ZIG encodes AtVTI11, which is a SNARE involved in vesicle transport to the vacuole. The fusion protein of SGR2 and green fluorescent protein localized to the vacuole and small organelles. These observations indicate that ZIG and SGR2 are involved in the formation and function of the vacuole, a notion supported by the results of subcellular analysis of the sgr2 and zig mutants with electron microscopy. These results strongly suggest that the vacuole participates in the early events of gravitropism and that SGR2 and ZIG functions are involved. PMID:11826298

The endoderm specifies the mesodermal niche for the germline in Drosophila via Delta-Notch signaling

PubMed Central

Okegbe, Tishina C.; DiNardo, Stephen

2011-01-01

Interactions between niche cells and stem cells are vital for proper control over stem cell self-renewal and differentiation. However, there are few tissues where the initial establishment of a niche has been studied. The Drosophila testis houses two stem cell populations, which each lie adjacent to somatic niche cells. Although these niche cells sustain spermatogenesis throughout life, it is not understood how their fate is established. Here, we show that Notch signaling is necessary to specify niche cell fate in the developing gonad. Surprisingly, our results indicate that adjacent endoderm is the source of the Notch-activating ligand Delta. We also find that niche cell specification occurs earlier than anticipated, well before the expression of extant markers for niche cell fate. This work further suggests that endoderm plays a dual role in germline development. The endoderm assists both in delivering germ cells to the somatic gonadal mesoderm, and in specifying the niche where these cells will subsequently develop as stem cells. Because in mammals primordial germ cells also track through endoderm on their way to the genital ridge, our work raises the possibility that conserved mechanisms are employed to regulate germline niche formation. PMID:21350008

[Association of folate metabolism genes MTRR and MTHFR with complex congenital abnormalities among Chinese population in Shanxi Province, China].

PubMed

Zhang, Qin; Bai, Bao-Ling; Liu, Xiao-Zhen; Miao, Chun-Yue; Li, Hui-Li

2014-08-01

To explore the association of polymorphisms in folate metabolism genes, methionine synthase reductase (MTRR) gene and 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, with complex congenital abnormalities and to further investigate its association with complex congenital abnormalities derived from three germ layers. A total of 250 cases of birth defects (with complex congenital abnormalities including congenital heart disease, neural tube defects, and craniofacial anomalies) in Shanxi Province, China were included in the study. MTRR single nucleotide polymorphism (SNP) (rs1801394) and MTHFR SNP (rs1801133) were genotyped by the SNaPshot method, and the genotyping results were compared with those of controls (n=420). SNPs rs1801394 and rs1801133 were associated with multiple birth defects. For the recessive model, individuals with GG genotype at rs1801394 and CC genotype at rs1801133 had a relatively low risk of developing birth defects, so the two genotypes were protective factors against birth defects. The homozygous recessive genotype at rs1801133, which served as a protective factor, was associated with ectoderm- or endoderm-derived complex congenital abnormalities, while the homozygous recessive genotype at rs1801394, which served as a protective factor, was associated with ectoderm-, mesoderm- or endoderm-derived complex congenital abnormalities. Among the Chinese population in Shanxi Province, the SNPs in folate metabolism genes (MTRR and MTHFR) are associated with complex congenital abnormalities and related to ectoderm, mesoderm or endoderm development.

Genomic analyses identify molecular subtypes of pancreatic cancer.

PubMed

Bailey, Peter; Chang, David K; Nones, Katia; Johns, Amber L; Patch, Ann-Marie; Gingras, Marie-Claude; Miller, David K; Christ, Angelika N; Bruxner, Tim J C; Quinn, Michael C; Nourse, Craig; Murtaugh, L Charles; Harliwong, Ivon; Idrisoglu, Senel; Manning, Suzanne; Nourbakhsh, Ehsan; Wani, Shivangi; Fink, Lynn; Holmes, Oliver; Chin, Venessa; Anderson, Matthew J; Kazakoff, Stephen; Leonard, Conrad; Newell, Felicity; Waddell, Nick; Wood, Scott; Xu, Qinying; Wilson, Peter J; Cloonan, Nicole; Kassahn, Karin S; Taylor, Darrin; Quek, Kelly; Robertson, Alan; Pantano, Lorena; Mincarelli, Laura; Sanchez, Luis N; Evers, Lisa; Wu, Jianmin; Pinese, Mark; Cowley, Mark J; Jones, Marc D; Colvin, Emily K; Nagrial, Adnan M; Humphrey, Emily S; Chantrill, Lorraine A; Mawson, Amanda; Humphris, Jeremy; Chou, Angela; Pajic, Marina; Scarlett, Christopher J; Pinho, Andreia V; Giry-Laterriere, Marc; Rooman, Ilse; Samra, Jaswinder S; Kench, James G; Lovell, Jessica A; Merrett, Neil D; Toon, Christopher W; Epari, Krishna; Nguyen, Nam Q; Barbour, Andrew; Zeps, Nikolajs; Moran-Jones, Kim; Jamieson, Nigel B; Graham, Janet S; Duthie, Fraser; Oien, Karin; Hair, Jane; Grützmann, Robert; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Wolfgang, Christopher L; Morgan, Richard A; Lawlor, Rita T; Corbo, Vincenzo; Bassi, Claudio; Rusev, Borislav; Capelli, Paola; Salvia, Roberto; Tortora, Giampaolo; Mukhopadhyay, Debabrata; Petersen, Gloria M; Munzy, Donna M; Fisher, William E; Karim, Saadia A; Eshleman, James R; Hruban, Ralph H; Pilarsky, Christian; Morton, Jennifer P; Sansom, Owen J; Scarpa, Aldo; Musgrove, Elizabeth A; Bailey, Ulla-Maja Hagbo; Hofmann, Oliver; Sutherland, Robert L; Wheeler, David A; Gill, Anthony J; Gibbs, Richard A; Pearson, John V; Waddell, Nicola; Biankin, Andrew V; Grimmond, Sean M

2016-03-03

Integrated genomic analysis of 456 pancreatic ductal adenocarcinomas identified 32 recurrently mutated genes that aggregate into 10 pathways: KRAS, TGF-β, WNT, NOTCH, ROBO/SLIT signalling, G1/S transition, SWI-SNF, chromatin modification, DNA repair and RNA processing. Expression analysis defined 4 subtypes: (1) squamous; (2) pancreatic progenitor; (3) immunogenic; and (4) aberrantly differentiated endocrine exocrine (ADEX) that correlate with histopathological characteristics. Squamous tumours are enriched for TP53 and KDM6A mutations, upregulation of the TP63∆N transcriptional network, hypermethylation of pancreatic endodermal cell-fate determining genes and have a poor prognosis. Pancreatic progenitor tumours preferentially express genes involved in early pancreatic development (FOXA2/3, PDX1 and MNX1). ADEX tumours displayed upregulation of genes that regulate networks involved in KRAS activation, exocrine (NR5A2 and RBPJL), and endocrine differentiation (NEUROD1 and NKX2-2). Immunogenic tumours contained upregulated immune networks including pathways involved in acquired immune suppression. These data infer differences in the molecular evolution of pancreatic cancer subtypes and identify opportunities for therapeutic development.

The zinc finger gene Xblimp1 controls anterior endomesodermal cell fate in Spemann's organizer.

PubMed Central

de Souza, F S; Gawantka, V; Gómez, A P; Delius, H; Ang, S L; Niehrs, C

1999-01-01

The anterior endomesoderm of the early Xenopus gastrula is a part of Spemann's organizer and is important for head induction. Here we describe Xblimp1, which encodes a zinc finger transcriptional repressor expressed in the anterior endomesoderm. Xblimp1 represses trunk mesoderm and induces anterior endomesoderm in a cooperative manner with the pan-endodermal gene Mix.1. Furthermore, Xblimp1 can cooperate with the BMP inhibitor chordin to induce ectopic heads, while a dominant-negative Xblimp1 inhibits head formation. The head inducer cerberus is positively regulated by Xblimp1 and is able to rescue microcephalic embryos caused by dominant-negative Xblimp1. Our results indicate that Xblimp1 is required for anterior endomesodermal cell fate and head induction. PMID:10545117

Development of hemipenes in the ball python snake Python regius.

PubMed

Leal, Francisca; Cohn, Martin J

2015-01-01

Within amniotes, external copulatory organs have undergone extensive morphological diversification. One of the most extreme examples is squamate (lizards and snakes) hemipenes, which are paired copulatory organs that extend from the lateral margins of the cloaca. Here, we describe the development of hemipenes in a basal snake, the ball python (Python regius). Snake hemipenes arise as a pair of lateral swellings on either side of the caudal part of the cloaca, and these paired outgrowths persist to form the left and right hemipenes. In non-squamate amniotes, external genitalia form from paired swellings that arise on the anterior side of the cloaca, which then fuse medially to form a single genital tubercle, the anlagen of the penis or clitoris. Whereas in non-squamate amniotes, Sonic hedgehog (Shh)-expressing cells of the cloacal endoderm form the urethral or sulcus epithelium and are required for phallus outgrowth, the hemipenes of squamates lack an endodermal contribution, and the sulcus does not express Shh. Thus, snake hemipenes differ from the genital tubercles of non-squamate amniotes both in their embryonic origins and in at least part of patterning mechanisms, which raises the possibility that hemipenes may not be direct homologs of the unpaired amniote penis. Nonetheless, we find that some developmental genes show similar expression patterns in snake hemipenes buds and non-squamate genital tubercles, suggesting that homologous developmental mechanisms are involved in aspects of external genital development across amniotes, even when these structures may have different developmental origins and may have arisen independently during evolution.

Identification and analysis of novel genes involved in gravitropism of Arabidopsis thaliana.

NASA Astrophysics Data System (ADS)

Morita, Miyo T.; Tasaka, Masao; Masatoshi Taniguchi, .

2012-07-01

Gravitropism is a continuous control with regard to the orientation and juxtaposition of the various parts of the plant body in response to gravity. In higher plants, the relative directional change of gravity is mainly suscepted in specialized cells called statocytes, followed by signal conversion from physical information into physiological information within the statocytes. We have studied the early process of shoot gravitropism, gravity sensing and signaling process, mainly by molecular genetic approach. In Arabidopsis shoot, statocytes are the endodermal cells. sgr1/scarcrow (scr) and sgr7/short-root (shr) mutants fail to form the endodermis and to respond to gravity in their inflorescence stems. Since both SGR1/SCR and SGR7/SHR are transcriptional factors, at least a subset of their downstream genes can be expected to be involved in gravitropism. In addition, eal1 (endodermal-amyloplast less 1), which exhibits no gravitropism in inflorescence stem but retains ability to form endodermis, is a hypomorphic allele of sgr7/shr. Take advantage of these mutants, we performed DNA microarray analysis and compared gene expression profiles between wild type and the mutants. We found that approx. 40 genes were commonly down-regulated in these mutants and termed them DGE (DOWN-REGULATED GENE IN EAL1) genes. DGE1 has sequence similarity to Oryza sativa LAZY1 that is involved in shoot gravitropism of rice. DGE2 has a short region homologous to DGE1. DTL (DGE TWO-LIKE}) that has 54% identity to DGE2 is found in Arabidopsis genome. All three genes are conserved in angiosperm but have no known functional domains or motifs. We analyzed T-DNA insertion for these genes in single or multiple combinations. In dge1 dge2 dtl triple mutant, gravitropic response of shoot, hypocotyl and root dramatically reduced. Now we are carrying out further physiological and molecular genetic analysis of the triple mutant.

Mesenchymal Stem Cells – Sources and Clinical Applications

PubMed Central

Klingemann, Hans; Matzilevich, David; Marchand, James

2008-01-01

Summary Although mesenchymal stem cells (MSC) from different tissue sources share many characteristics and generally fulfill accepted criteria for MSC (plastic adherence, certain surface marker expression, and ability to differentiate into mesenchymal tissues), we are increasingly learning that they can be distinguished at the level of cytokine production and gene expression profiles. Their ability to differentiate into different tissues including endodermal and ectodermal lineages, also varies according to tissue origin. Importantly, MSC from fetal sources can undergo more cell divisions before they reach senescence than MSC from adult tissue such as bone marrow or adipose tissue. As we learn more about the differentiation and plasticity of MSC from different sources, health care providers in the future will use them tailored to different medical indications. PMID:21512642

Revising the embryonic origin of thyroid C cells in mice and humans

PubMed Central

Johansson, Ellen; Andersson, Louise; Örnros, Jessica; Carlsson, Therese; Ingeson-Carlsson, Camilla; Liang, Shawn; Dahlberg, Jakob; Jansson, Svante; Parrillo, Luca; Zoppoli, Pietro; Barila, Guillermo O.; Altschuler, Daniel L.; Padula, Daniela; Lickert, Heiko; Fagman, Henrik; Nilsson, Mikael

2015-01-01

Current understanding infers a neural crest origin of thyroid C cells, the major source of calcitonin in mammals and ancestors to neuroendocrine thyroid tumors. The concept is primarily based on investigations in quail–chick chimeras involving fate mapping of neural crest cells to the ultimobranchial glands that regulate Ca2+ homeostasis in birds, reptiles, amphibians and fishes, but whether mammalian C cell development involves a homologous ontogenetic trajectory has not been experimentally verified. With lineage tracing, we now provide direct evidence that Sox17+ anterior endoderm is the only source of differentiated C cells and their progenitors in mice. Like many gut endoderm derivatives, embryonic C cells were found to coexpress pioneer factors forkhead box (Fox) a1 and Foxa2 before neuroendocrine differentiation takes place. In the ultimobranchial body epithelium emerging from pharyngeal pouch endoderm in early organogenesis, differential Foxa1/Foxa2 expression distinguished two spatially separated pools of C cell precursors with different growth properties. A similar expression pattern was recapitulated in medullary thyroid carcinoma cells in vivo, consistent with a growth-promoting role of Foxa1. In contrast to embryonic precursor cells, C cell-derived tumor cells invading the stromal compartment downregulated Foxa2, foregoing epithelial-to-mesenchymal transition designated by loss of E-cadherin; both Foxa2 and E-cadherin were re-expressed at metastatic sites. These findings revise mammalian C cell ontogeny, expand the neuroendocrine repertoire of endoderm and redefine the boundaries of neural crest diversification. The data further underpin distinct functions of Foxa1 and Foxa2 in both embryonic and tumor development. PMID:26395490

Ancient connection between NKL genes and the mesoderm? Insights from Tlx expression in a ctenophore.

PubMed

Derelle, Romain; Manuel, Michaël

2007-04-01

In recent years, evo-devo studies on non-bilaterian metazoans have improved our understanding of the early evolution of animal body plans. In particular, works on cnidarians suggested that contrary to classical views, the mesoderm originated far before the emergence of the Bilateria. In this context, a synthesis of genomic and functional data concerning the Antennapedia (Antp) superclass of homeobox genes suggested that early in animal evolution, each of the three germ layers was under the control of one cluster of Antp genes. In particular, the patterning and differentiation of the mesoderm was under the control of the NKL cluster. The ctenophores stand as a key taxon with respect to such issues because unlike other non-bilaterian phyla, their intermediate germ layer satisfies the strict embryological definition of a mesoderm. For that reason, we investigated the only known member of the NKL group in Ctenophora, a gene previously isolated from Pleurobrachia and attributed to the Tlx family. In our analysis of the NKL group, this ctenophore gene branches as the sister-group of bilaterian Tlx genes, but without statistical support. The expression pattern of this gene was revealed by in situ hybridisation in the adult ctenophore. The expression territories of PpiTlx are predominantly ectodermal, in two distinct types of ciliated epidermal cells and in one category of gland cells. We also identified a probable endodermal site of expression. Because we failed to detect any mesodermal expression, the results do not provide support to the hypothesis of an ancient functional association between the NKL group and the mesoderm.

Differential regulation of ParaHox genes by retinoic acid in the invertebrate chordate amphioxus (Branchiostoma floridae).

PubMed

Osborne, Peter W; Benoit, Gérard; Laudet, Vincent; Schubert, Michael; Ferrier, David E K

2009-03-01

The ParaHox cluster is the evolutionary sister to the Hox cluster. Like the Hox cluster, the ParaHox cluster displays spatial and temporal regulation of the component genes along the anterior/posterior axis in a manner that correlates with the gene positions within the cluster (a feature called collinearity). The ParaHox cluster is however a simpler system to study because it is composed of only three genes. We provide a detailed analysis of the amphioxus ParaHox cluster and, for the first time in a single species, examine the regulation of the cluster in response to a single developmental signalling molecule, retinoic acid (RA). Embryos treated with either RA or RA antagonist display altered ParaHox gene expression: AmphiGsx expression shifts in the neural tube, and the endodermal boundary between AmphiXlox and AmphiCdx shifts its anterior/posterior position. We identified several putative retinoic acid response elements and in vitro assays suggest some may participate in RA regulation of the ParaHox genes. By comparison to vertebrate ParaHox gene regulation we explore the evolutionary implications. This work highlights how insights into the regulation and evolution of more complex vertebrate arrangements can be obtained through studies of a simpler, unduplicated amphioxus gene cluster.

An early role for sonic hedgehog from foregut endoderm in jaw development: ensuring neural crest cell survival.

PubMed

Brito, José M; Teillet, Marie-Aimée; Le Douarin, Nicole M

2006-08-01

We have investigated the role of Sonic hedgehog (Shh) in the development of facial structures by depriving chicken embryos of the most anterior sources of this morphogen, including the prechordal plate and the anterior ventral endoderm of the foregut, before the onset of neural crest cell (NCC) migration to the first branchial arch (BA1). The entire forehead, including the foregut endoderm, was removed at 5- to 10-somite stage (ss), which led to the absence of the lower jaw when the operation was performed before 7-ss. If the embryos were deprived of their forehead at 8- to 10-ss, they were later on endowed with a lower beak. In embryos that were operated on early, the NCCs migrated normally to BA1 but were subjected to massive apoptosis a few hours later. Cell death did not occur when forehead excision was performed at a later stage. In this case, onward expression of Shh in the ventral foregut endoderm extended caudally over the excision limit, and we hypothesized that absence of Shh production by the endoderm in embryos that were operated on early could be responsible for the NCC apoptosis and the failure of BA1 development. We thus provided exogenous Shh to the embryos that were operated on before 7-ss. In this case, the development of the lower jaw was rescued. Therefore, Shh derived from the ventral foregut endoderm ensures the survival of NCCs at a critical stage of BA1 development.

Neurogenic gene regulatory pathways in the sea urchin embryo.

PubMed

Wei, Zheng; Angerer, Lynne M; Angerer, Robert C

2016-01-15

During embryogenesis the sea urchin early pluteus larva differentiates 40-50 neurons marked by expression of the pan-neural marker synaptotagmin B (SynB) that are distributed along the ciliary band, in the apical plate and pharyngeal endoderm, and 4-6 serotonergic neurons that are confined to the apical plate. Development of all neurons has been shown to depend on the function of Six3. Using a combination of molecular screens and tests of gene function by morpholino-mediated knockdown, we identified SoxC and Brn1/2/4, which function sequentially in the neurogenic regulatory pathway and are also required for the differentiation of all neurons. Misexpression of Brn1/2/4 at low dose caused an increase in the number of serotonin-expressing cells and at higher dose converted most of the embryo to a neurogenic epithelial sphere expressing the Hnf6 ciliary band marker. A third factor, Z167, was shown to work downstream of the Six3 and SoxC core factors and to define a branch specific for the differentiation of serotonergic neurons. These results provide a framework for building a gene regulatory network for neurogenesis in the sea urchin embryo. © 2016. Published by The Company of Biologists Ltd.

Differentiation of Human Mesenchymal Stem Cells into Insulin Producing Cells by Using A Lentiviral Vector Carrying PDX1.

PubMed

Allahverdi, Amir; Abroun, Saied; Jafarian, Arefeh; Soleimani, Masoud; Taghikhani, Mohammad; Eskandari, Fatemeh

2015-01-01

Type I diabetes is an immunologically-mediated devastation of insulin producing cells (IPCs) in the pancreatic islet. Stem cells that produce β-cells are a new promising tool. Adult stem cells such as mesenchymal stem cells (MSCs) are self renewing multi potent cells showing capabilities to differentiate into ectodermal, mesodermal and endodermal tissues. Pancreatic and duodenal homeobox factor 1 (PDX1) is a master regulator gene required for embryonic development of the pancreas and is crucial for normal pancreatic islets activities in adults. We induced the over-expression of the PDX1 gene in human bone marrow MSCs (BM-MSCs) by Lenti-PDX1 in order to generate IPCs. Next, we examine the ability of the cells by measuring insulin/c-peptide production and INSULIN and PDX1 gene expressions. After transduction, MSCs changed their morphology at day 5 and gradually differentiated into IPCs. INSULIN and PDX1 expressions were confirmed by real time polymerase chain reaction (RT-PCR) and immunostaining. IPC secreted insulin and C-peptide in the media that contained different glucose concentrations. MSCs differentiated into IPCs by genetic manipulation. Our result showed that lentiviral vectors could deliver PDX1 gene to MSCs and induce pancreatic differentiation.

Overexpression of COUP-TF1 in murine embryonic stem cells reduces retinoic acid-associated growth arrest and increases extraembryonic endoderm gene expression.

PubMed

Zhuang, Yong; Gudas, Lorraine J

2008-09-01

Vitamin A (retinol [Rol]) and its metabolites are essential for embryonic development. The Rol metabolite all-trans retinoic acid (RA) is a biologically active form of Rol. The orphan nuclear receptor chicken ovalbumin upstream promoter-transcription-factors (COUP-TF) proteins have been implicated in the regulation of several important biological processes, such as embryonic development and neuronal cell differentiation. Because there is evidence that COUP-TFs function in the retinoid signaling network during development and differentiation, we generated murine embryonic stem (ES) cell lines which stably and constitutively overexpress COUP-TF1 (NR2F1) and we analyzed RA-induced differentiation. COUP-TF1 overexpression resulted in reduced RA-associated growth arrest. A 2.4+/-0.17-fold higher Nanog mRNA level was seen in COUP-TF1 overexpressing lines, as compared with wild-type (WT) ES cells, after a 72 hr RA treatment. We also showed that COUP-TF1 overexpression enhanced RA-induced extraembryonic endoderm gene expression. Specifically, COUP-TF1 overexpression increased mRNA levels of GATA6 by 3.3+/-0.3-fold, GATA4 by 3.6+/-0.1-fold, laminin B1 (LAMB1) by 3.4+/-0.1-fold, LAMC1 by 3.4+/-0.2-fold, Dab2 by 2.4+0.1-fold, and SOX17 by 2.5-fold at 72 hr after RA treatment plus LIF, as compared with the increases seen in WT ES cells. However, RA-induced neurogenesis was unaffected by COUP-TF1 overexpression, as shown by the equivalent levels of expression of NeuroD1, nestin, GAP43 and other neuronal markers. Our results revealed for the first time that COUP-TF1 is an important signaling molecule during vitamin A (Rol)-mediated very early stage of embryonic development.

Bile system morphogenesis defects and liver dysfunction upon targeted deletion of HNF1beta.

PubMed

Coffinier, Catherine; Gresh, Lionel; Fiette, Laurence; Tronche, François; Schütz, Günther; Babinet, Charles; Pontoglio, Marco; Yaniv, Moshe; Barra, Jacqueline

2002-04-01

The inactivation of the Hnf1beta gene identified an essential role in epithelial differentiation of the visceral endoderm and resulted in early embryonic death. In the present study, we have specifically inactivated this gene in hepatocytes and bile duct cells using the Cre/loxP system. Mutant animals exhibited severe jaundice caused by abnormalities of the gallbladder and intrahepatic bile ducts (IHBD). The paucity of small IHBD was linked to a failure in the organization of duct structures during liver organogenesis, suggesting an essential function of Hnf1b in bile duct morphogenesis. Mutant mice also lacked interlobular arteries. As HNF1beta is not expressed in these cells, it further emphasizes the link between arterial and biliary formation. Hepatocyte metabolism was also affected and we identified hepatocyte-specific HNF1beta target genes involved in bile acids sensing and in fatty acid oxidation.

Efficient programming of human eye conjunctiva-derived induced pluripotent stem (ECiPS) cells into definitive endoderm-like cells.

PubMed

Massumi, Mohammad; Hoveizi, Elham; Baktash, Parvaneh; Hooti, Abdollah; Ghazizadeh, Leili; Nadri, Samad; Pourasgari, Farzaneh; Hajarizadeh, Athena; Soleimani, Masoud; Nabiuni, Mohammad; Khorramizadeh, Mohammad R

2014-03-10

Due to pluripotency of induced pluripotent stem (iPS) cells, and the lack of immunological incompatibility and ethical issues, iPS cells have been considered as an invaluable cell source for future cell replacement therapy. This study was aimed first at establishment of novel iPS cells, ECiPS, which directly reprogrammed from human Eye Conjunctiva-derived Mesenchymal Stem Cells (EC-MSCs); second, comparing the inductive effects of Wnt3a/Activin A biomolecules to IDE1 small molecule in derivation of definitive endoderm (DE) from the ECiPS cells. To that end, first, the EC-MSCs were transduced by SOKM-expressing lentiviruses and characterized for endogenous expression of embryonic markers Then the established ECiPS cells were induced to DE formation by Wnt3a/Activin A or IDE1. Quantification of GSC, Sox17 and Foxa2 expression, as DE-specific markers, in both mRNA and protein levels revealed that induction of ECiPS cells by either Wnt3a/Activin A or IDE1 could enhance the expression level of the genes; however the levels of increase were higher in Wnt3a/Activin A induced ECiPS-EBs than IDE1 induced cells. Furthermore, the flow cytometry analyses showed no synergistic effect between Activin A and Wnt3a to derive DE-like cells from ECiPS cells. The comparative findings suggest that although both Wnt3a/Activin A signaling and IDE1 molecule could be used for differentiation of iPS into DE cells, the DE-inducing effect of Wnt3a/Activin A was statistically higher than IDE1. Copyright © 2014 Elsevier Inc. All rights reserved.

BMP antagonism by Noggin is required in presumptive notochord cells for mammalian foregut morphogenesis.

PubMed

Fausett, Sarah R; Brunet, Lisa J; Klingensmith, John

2014-07-01

Esophageal atresia with tracheoesophageal fistula (EA/TEF) is a serious human birth defect, in which the esophagus ends before reaching the stomach, and is aberrantly connected with the trachea. Several mouse models of EA/TEF have recently demonstrated that proper dorsal/ventral (D/V) patterning of the primitive anterior foregut endoderm is essential for correct compartmentalization of the trachea and esophagus. Here we elucidate the pathogenic mechanisms underlying the EA/TEF that occurs in mice lacking the BMP antagonist Noggin, which display correct dorsal/ventral patterning. To clarify the mechanism of this malformation, we use spatiotemporal manipulation of Noggin and BMP receptor 1A conditional alleles during foregut development. Surprisingly, we find that the expression of Noggin in the compartmentalizing endoderm is not required to generate distinct tracheal and esophageal tubes. Instead, we show that Noggin and BMP signaling attenuation are required in the early notochord to correctly resolve notochord cells from the dorsal foregut endoderm, which in turn, appears to be a prerequisite for foregut compartmentalization. Collectively, our findings support an emerging model for a mechanism underlying EA/TEF in which impaired notochord resolution from the early endoderm causes the foregut to be hypo-cellular just prior to the critical period of compartmentalization. Our further characterizations suggest that Noggin may regulate a cell rearrangement process that involves reciprocal E-cadherin and Zeb1 expression in the resolving notochord cells. Copyright © 2014. Published by Elsevier Inc.

Analysis of NUAK1 and NUAK2 expression during early chick development reveals specific patterns in the developing head.

PubMed

Bekri, Abdelhamid; Billaud, Marc; Thélu, Jacques

2014-01-01

Several human diseases are associated with the NUAK1 and NUAK2 genes. These genes encode kinases, members of the AMPK-related kinases (ARK) gene family. Both NUAK1 and NUAK2 are known targets of the serine threonine kinase LKB1, a tumor suppressor involved in regulating cell polarity. While much is known about their functions in disease, their expression pattern in normal development has not been extensively studied. Here, we present the expression patterns for NUAK1 and NUAK2 in the chick during early-stage embryogenesis, until day 3 (Hamburger and Hamilton stage HH20). Several embryonic structures, in particular the nascent head, showed distinct expression levels. NUAK1 expression was first detected at stage HH6 in the rostral neural folds. It was then expressed (HH7-11) throughout the encephalalon, predominantly in the telencephalon and mesencephalon. NUAK1 expression was also detected in the splanchnic endoderm area at HH8-10, and in the vitellin vein derived from this area, but not in the heart. NUAK2 expression was first detected at stage HH6 in the neural folds. It was then found throughout the encephalon at stage HH20. Particular attention was paid in this study to the dorsal ectoderm at stages HH7 and HH8, where a local deficit or accumulation of NUAK2 mRNA were found to correlate with the direction of curvature of the neural plate. This is the first description of NUAK1 and NUAK2 expression patterns in the chick during early development; it reveals non-identical expression profiles for both genes in neural development.

Phytochromes inhibit hypocotyl negative gravitropism by regulating the development of endodermal amyloplasts through phytochrome-interacting factors

PubMed Central

Kim, Keunhwa; Shin, Jieun; Lee, Sang-Hee; Kweon, Hee-Seok; Maloof, Julin N.; Choi, Giltsu

2011-01-01

Phytochromes are red and far-red light photoreceptors that regulate various aspects of plant development. One of the less-understood roles of phytochromes is the inhibition of hypocotyl negative gravitropism, which refers to the loss of hypocotyl gravitropism and resulting random growth direction in red or far-red light. This light response allows seedlings to curve toward blue light after emergence from the soil and enhances seedling establishment in the presence of mulch. Phytochromes inhibit hypocotyl negative gravitropism by inhibiting four phytochrome-interacting factors (PIF1, PIF3, PIF4, PIF5), as shown by hypocotyl agravitropism of dark-grown pif1 pif3 pif4 pif5 quadruple mutants. We show that phytochromes inhibit negative gravitropism by converting starch-filled gravity-sensing endodermal amyloplasts to other plastids with chloroplastic or etioplastic features in red or far-red light, whereas PIFs promote negative gravitropism by inhibiting the conversion of endodermal amyloplasts to etioplasts in the dark. By analyzing transgenic plants expressing PIF1 with an endodermis-specific SCARECROW promoter, we further show that endodermal PIF1 is sufficient to inhibit the conversion of endodermal amyloplasts to etioplasts and hypocotyl negative gravitropism of the pif quadruple mutant in the dark. Although the functions of phytochromes in gravitropism and chloroplast development are normally considered distinct, our results indicate that these two functions are closely related. PMID:21220341

Phytochromes inhibit hypocotyl negative gravitropism by regulating the development of endodermal amyloplasts through phytochrome-interacting factors.

PubMed

Kim, Keunhwa; Shin, Jieun; Lee, Sang-Hee; Kweon, Hee-Seok; Maloof, Julin N; Choi, Giltsu

2011-01-25

Phytochromes are red and far-red light photoreceptors that regulate various aspects of plant development. One of the less-understood roles of phytochromes is the inhibition of hypocotyl negative gravitropism, which refers to the loss of hypocotyl gravitropism and resulting random growth direction in red or far-red light. This light response allows seedlings to curve toward blue light after emergence from the soil and enhances seedling establishment in the presence of mulch. Phytochromes inhibit hypocotyl negative gravitropism by inhibiting four phytochrome-interacting factors (PIF1, PIF3, PIF4, PIF5), as shown by hypocotyl agravitropism of dark-grown pif1 pif3 pif4 pif5 quadruple mutants. We show that phytochromes inhibit negative gravitropism by converting starch-filled gravity-sensing endodermal amyloplasts to other plastids with chloroplastic or etioplastic features in red or far-red light, whereas PIFs promote negative gravitropism by inhibiting the conversion of endodermal amyloplasts to etioplasts in the dark. By analyzing transgenic plants expressing PIF1 with an endodermis-specific SCARECROW promoter, we further show that endodermal PIF1 is sufficient to inhibit the conversion of endodermal amyloplasts to etioplasts and hypocotyl negative gravitropism of the pif quadruple mutant in the dark. Although the functions of phytochromes in gravitropism and chloroplast development are normally considered distinct, our results indicate that these two functions are closely related.

Tissue-specific roles for sonic hedgehog signaling in establishing thymus and parathyroid organ fate

PubMed Central

Bain, Virginia E.; Gordon, Julie; O'Neil, John D.; Ramos, Isaias; Richie, Ellen R.

2016-01-01

The thymus and parathyroids develop from third pharyngeal pouch (3rd pp) endoderm. Our previous studies show that Shh null mice have smaller, aparathyroid primordia in which thymus fate specification extends into the pharynx. SHH signaling is active in both dorsal pouch endoderm and neighboring neural crest (NC) mesenchyme. It is unclear which target tissue of SHH signaling is required for the patterning defects in Shh mutants. Here, we used a genetic approach to ectopically activate or delete the SHH signal transducer Smo in either pp endoderm or NC mesenchyme. Although no manipulation recapitulated the Shh null phenotype, manipulation of SHH signaling in either the endoderm or NC mesenchyme had direct and indirect effects on both cell types during fate specification and organogenesis. SHH pathway activation throughout pouch endoderm activated ectopic Tbx1 expression and partially suppressed the thymus-specific transcription factor Foxn1, identifying Tbx1 as a key target of SHH signaling in the 3rd pp. However, ectopic SHH signaling was insufficient to expand the GCM2-positive parathyroid domain, indicating that multiple inputs, some of which might be independent of SHH signaling, are required for parathyroid fate specification. These data support a model in which SHH signaling plays both positive and negative roles in patterning and organogenesis of the thymus and parathyroids. PMID:27633995

Expression of an Msx homeobox gene in ascidians: insights into the archetypal chordate expression pattern.

PubMed

Ma, L; Swalla, B J; Zhou, J; Dobias, S L; Bell, J R; Chen, J; Maxson, R E; Jeffery, W R

1996-03-01

The Msx homeobox genes are expressed in complex patterns during vertebrate development in conjunction with inductive tissue interactions. As a means of understanding the archetypal role of Msx genes in chordates, we have isolated and characterized an Msx gene in ascidians, protochordates with a relatively simple body plan. The Mocu Msx-a and McMsx-a genes, isolated from the ascidians Molgula oculata and Molgula citrina, respectively, have homeodomains that place them in the msh-like subclass of Msx genes. Therefore, the Molgula Msx-a genes are most closely related to the msh genes previously identified in a number of invertebrates. Southern blot analysis suggests that there are one or two copies of the Msx-a gene in the Molgula genome. Northern blot and RNase protection analysis indicate that Msx-a transcripts are restricted to the developmental stages of the life cycle. In situ hybridization showed that Msx-a mRNA first appears just before gastrulation in the mesoderm (presumptive notochord and muscle) and ectoderm (neural plate) cells. Transcript levels decline in mesoderm cells after the completion of gastrulation, but are enhanced in the folding neural plate during neurulation. Later, Msx-a mRNA is also expressed in the posterior ectoderm and in a subset of the tail muscle cells. The ectoderm and mesoderm cells that express Msx-a are undergoing morphogenetic movements during gastrulation, neurulation, and tail formation. Msx-a expression ceases after these cells stop migrating. The ascidian M. citrina, in which adult tissues and organs begin to develop precociously in the larva, was used to study Msx-a expression during adult development. Msx-a transcripts are expressed in the heart primordium and the rudiments of the ampullae, epidermal protrusions with diverse functions in the juvenile. The heart and ampullae develop in regions where mesenchyme cells interact with endodermal or epidermal epithelia. A comparison of the expression patterns of the Molgula genes with those of their vertebrate congeners suggests that the archetypal roles of the Msx genes may be in morphogenetic movements during embryogenesis and in mesenchymal-epithelial interactions during organogenesis.

Diagnostic value of MUC4 immunostaining in distinguishing epithelial mesothelioma and lung adenocarcinoma.

PubMed

Llinares, Karine; Escande, Fabienne; Aubert, Sébastien; Buisine, Marie-Pierre; de Bolos, Carme; Batra, Surinder K; Gosselin, Bernard; Aubert, Jean-Pierre; Porchet, Nicole; Copin, Marie-Christine

2004-02-01

The distinction between pleural malignant mesothelioma and pleural infiltration by adenocarcinomas has complex therapeutic and medicolegal implications. Although the panel of adenocarcinoma-associated antibodies and one or two mesothelioma markers is useful in this purpose, most of these antibodies are not totally specific. We determined the diagnostic value of MUC4 immunostaining in this issue. MUC4 gene expression was also studied by in situ hybridization and RT-PCR. MUC4 is a membrane-bound mucin that has been suggested to be implicated in malignant progression in humans and rats. The MUC4 gene is expressed in various normal epithelial tissues of endodermic origin and carcinomas. In the respiratory tract, MUC4 transcripts have been detected in normal respiratory epithelium and lung carcinomas. MUC4 protein was expressed in 32 of 35 (91.4%) lung adenocarcinomas on paraffin-embedded tissue. None of the 41 malignant mesotheliomas nor the 32 cases of benign mesothelial cells expressed MUC4 at the protein and mRNA levels. We conclude that MUC4 is a very specific (100%) and sensitive (91.4%) marker of lung adenocarcinomas on paraffin-embedded tissue that could be useful in diagnostic practice in the distinction between malignant mesothelioma and adenocarcinoma.

New gene targets for glucagon-like peptide-1 during embryonic development and in undifferentiated pluripotent cells.

PubMed

Sanz, Carmen; Blázquez, Enrique

2011-09-01

In humans, glucagon-like peptide (GLP-1) functions during adult life as an incretin hormone with anorexigenic and antidiabetogenic properties. Also, the therapeutic potential of GLP-1 in preventing the adipocyte hyperplasia associated with obesity and in bolstering the maintenance of human mesenchymal stem cell (hMSC) stores by promoting the proliferation and cytoprotection of hMSC seems to be relevant. Since these observations suggest a role for GLP-1 during developmental processes, the aim of the present work was to characterize GLP-1 in early development as well as its gene targets in mouse embryonic stem (mES) cells. Mouse embryos E6, E8, and E10.5 and pluripotent mES were used for the inmunodetection of GLP-1 and GLP-1 receptor. Quantitative real-time PCR was used to determine the expression levels of GLP-1R in several tissues from E12.5 mouse embryos. Additionally, GLP-1 gene targets were studied in mES by multiple gene expression analyses. GLP-1 and its receptors were identified in mES and during embryonic development. In pluripotent mES, GLP-1 modified the expression of endodermal, ectodermal, and mesodermal gene markers as well as sonic hedgehog, noggin, members of the fibroblast and hepatic growth factor families, and others involved in pancreatic development. Additionally, GLP-1 promoted the expression of the antiapoptotic gene bcl2 and at the same time reduced proapoptotic caspase genes. Our results indicate that apart from the effects and therapeutic benefits of GLP-1 in adulthood, it may have additional gene targets in mES cells during embryonic life. Furthermore, the pathophysiological implications of GLP-1 imbalance in adulthood may have a counterpart during development.

Inactivation of the Huntington's disease gene (Hdh) impairs anterior streak formation and early patterning of the mouse embryo.

PubMed

Woda, Juliana M; Calzonetti, Teresa; Hilditch-Maguire, Paige; Duyao, Mabel P; Conlon, Ronald A; MacDonald, Marcy E

2005-08-18

Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdh(ex4/5) huntingtin deficient embryos. In the absence of huntingtin, expression of nutritive genes appears normal but E7.0-7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury) and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE) are specified. Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in Huntington's disease.

Roles of GATA6 during Gonadal Development in Japanese Flounder: Gonadogenesis, Regulation of Gender-Related Genes, Estrogen Formation and Gonadal Function Maintenance.

PubMed

Li, Zan; Liu, Xiumei; Sun, Yan; Liu, Jinxiang; Liu, Yuezhong; Wang, Mengxun; Zhang, Quanqi; Wang, Xubo

2017-01-16

GATA-binding protein 6 (GATA6), a highly-conserved transcription factor of the GATA family plays an important role in gonadal cell proliferation, differentiation and endoderm development. In this study, the full-length cDNA of GATA6 of Paralichthys olivaceus (Japanese flounder) was obtained. Phylogenetic, gene structure and synteny analyses demonstrated that GATA6 of P. olivaceus is homologous to that of teleosts and tetrapods. The P. olivaceus GATA6 transcript showed higher expression in testis than in ovary, demonstrating a sexually dimorphic gene expression. During embryonic development, the expression of P. olivaceus GATA6 increased at the blastula stage, demonstrating that GATA6 is involved in morphogenesis. Results of in situ hybridization showed that GATA6 signals were detected in Sertoli cells, oogonia and oocytes. Moreover, 17α methyl testosterone, a male hormone, could moderately upregulate P. olivaceus GATA6 and downregulate P. olivaceus aromatase CYP19A1 in testis cells. These results suggest that GATA6 may play an important role in gonadal development in P. olivaceus . This study provides valuable information on the function of P. olivaceus GATA6, laying the foundation for further development of breeding techniques in this species.

Roles of GATA6 during Gonadal Development in Japanese Flounder: Gonadogenesis, Regulation of Gender-Related Genes, Estrogen Formation and Gonadal Function Maintenance

PubMed Central

Li, Zan; Liu, Xiumei; Sun, Yan; Liu, Jinxiang; Liu, Yuezhong; Wang, Mengxun; Zhang, Quanqi; Wang, Xubo

2017-01-01

GATA-binding protein 6 (GATA6), a highly-conserved transcription factor of the GATA family plays an important role in gonadal cell proliferation, differentiation and endoderm development. In this study, the full-length cDNA of GATA6 of Paralichthys olivaceus (Japanese flounder) was obtained. Phylogenetic, gene structure and synteny analyses demonstrated that GATA6 of P. olivaceus is homologous to that of teleosts and tetrapods. The P. olivaceus GATA6 transcript showed higher expression in testis than in ovary, demonstrating a sexually dimorphic gene expression. During embryonic development, the expression of P. olivaceus GATA6 increased at the blastula stage, demonstrating that GATA6 is involved in morphogenesis. Results of in situ hybridization showed that GATA6 signals were detected in Sertoli cells, oogonia and oocytes. Moreover, 17α methyl testosterone, a male hormone, could moderately upregulate P. olivaceus GATA6 and downregulate P. olivaceus aromatase CYP19A1 in testis cells. These results suggest that GATA6 may play an important role in gonadal development in P. olivaceus. This study provides valuable information on the function of P. olivaceus GATA6, laying the foundation for further development of breeding techniques in this species. PMID:28275215

Mouth development.

PubMed

Chen, Justin; Jacox, Laura A; Saldanha, Francesca; Sive, Hazel

2017-09-01

A mouth is present in all animals, and comprises an opening from the outside into the oral cavity and the beginnings of the digestive tract to allow eating. This review focuses on the earliest steps in mouth formation. In the first half, we conclude that the mouth arose once during evolution. In all animals, the mouth forms from ectoderm and endoderm. A direct association of oral ectoderm and digestive endoderm is present even in triploblastic animals, and in chordates, this region is known as the extreme anterior domain (EAD). Further support for a single origin of the mouth is a conserved set of genes that form a 'mouth gene program' including foxA and otx2. In the second half of this review, we discuss steps involved in vertebrate mouth formation, using the frog Xenopus as a model. The vertebrate mouth derives from oral ectoderm from the anterior neural ridge, pharyngeal endoderm and cranial neural crest (NC). Vertebrates form a mouth by breaking through the body covering in a precise sequence including specification of EAD ectoderm and endoderm as well as NC, formation of a 'pre-mouth array,' basement membrane dissolution, stomodeum formation, and buccopharyngeal membrane perforation. In Xenopus, the EAD is also a craniofacial organizer that guides NC, while reciprocally, the NC signals to the EAD to elicit its morphogenesis into a pre-mouth array. Human mouth anomalies are prevalent and are affected by genetic and environmental factors, with understanding guided in part by use of animal models. WIREs Dev Biol 2017, 6:e275. doi: 10.1002/wdev.275 For further resources related to this article, please visit the WIREs website. © 2017 The Authors. WIREs Developmental Biology published by Wiley Periodicals, Inc.

Timing of Tissue-specific Cell Division Requires a Differential Onset of Zygotic Transcription during Metazoan Embryogenesis*

PubMed Central

Wong, Ming-Kin; Guan, Daogang; Ng, Kaoru Hon Chun; Ho, Vincy Wing Sze; An, Xiaomeng; Li, Runsheng; Ren, Xiaoliang

2016-01-01

Metazoan development demands not only precise cell fate differentiation but also accurate timing of cell division to ensure proper development. How cell divisions are temporally coordinated during development is poorly understood. Caenorhabditis elegans embryogenesis provides an excellent opportunity to study this coordination due to its invariant development and widespread division asynchronies. One of the most pronounced asynchronies is a significant delay of cell division in two endoderm progenitor cells, Ea and Ep, hereafter referred to as E2, relative to its cousins that mainly develop into mesoderm organs and tissues. To unravel the genetic control over the endoderm-specific E2 division timing, a total of 822 essential and conserved genes were knocked down using RNAi followed by quantification of cell cycle lengths using in toto imaging of C. elegans embryogenesis and automated lineage. Intriguingly, knockdown of numerous genes encoding the components of general transcription pathway or its regulatory factors leads to a significant reduction in the E2 cell cycle length but an increase in cell cycle length of the remaining cells, indicating a differential requirement of transcription for division timing between the two. Analysis of lineage-specific RNA-seq data demonstrates an earlier onset of transcription in endoderm than in other germ layers, the timing of which coincides with the birth of E2, supporting the notion that the endoderm-specific delay in E2 division timing demands robust zygotic transcription. The reduction in E2 cell cycle length is frequently associated with cell migration defect and gastrulation failure. The results suggest that a tissue-specific transcriptional activation is required to coordinate fate differentiation, division timing, and cell migration to ensure proper development. PMID:27056332

Conservation of the Nucleotide Excision Repair Pathway: Characterization of Hydra Xeroderma Pigmentosum Group F Homolog

PubMed Central

Barve, Apurva; Ghaskadbi, Saroj; Ghaskadbi, Surendra

2013-01-01

Hydra, one of the earliest metazoans with tissue grade organization and nervous system, is an animal with a remarkable regeneration capacity and shows no signs of organismal aging. We have for the first time identified genes of the nucleotide excision repair (NER) pathway from hydra. Here we report cloning and characterization of hydra homolog of xeroderma pigmentosum group F (XPF) gene that encodes a structure-specific 5′ endonuclease which is a crucial component of NER. In silico analysis shows that hydra XPF amino acid sequence is very similar to its counterparts from other animals, especially vertebrates, and shows all features essential for its function. By in situ hybridization, we show that hydra XPF is expressed prominently in the multipotent stem cell niche in the central region of the body column. Ectoderm of the diploblastic hydra was shown to express higher levels of XPF as compared to the endoderm by semi-quantitative RT-PCR. Semi-quantitative RT-PCR analysis also demonstrated that interstitial cells, a multipotent and rapidly cycling stem cell lineage of hydra, express higher levels of XPF mRNA than other cell types. Our data show that XPF and by extension, the NER pathway is highly conserved during evolution. The prominent expression of an NER gene in interstitial cells may have implications for the lack of senescence in hydra. PMID:23577191

Conservation of the nucleotide excision repair pathway: characterization of hydra Xeroderma Pigmentosum group F homolog.

PubMed

Barve, Apurva; Ghaskadbi, Saroj; Ghaskadbi, Surendra

2013-01-01

Hydra, one of the earliest metazoans with tissue grade organization and nervous system, is an animal with a remarkable regeneration capacity and shows no signs of organismal aging. We have for the first time identified genes of the nucleotide excision repair (NER) pathway from hydra. Here we report cloning and characterization of hydra homolog of xeroderma pigmentosum group F (XPF) gene that encodes a structure-specific 5' endonuclease which is a crucial component of NER. In silico analysis shows that hydra XPF amino acid sequence is very similar to its counterparts from other animals, especially vertebrates, and shows all features essential for its function. By in situ hybridization, we show that hydra XPF is expressed prominently in the multipotent stem cell niche in the central region of the body column. Ectoderm of the diploblastic hydra was shown to express higher levels of XPF as compared to the endoderm by semi-quantitative RT-PCR. Semi-quantitative RT-PCR analysis also demonstrated that interstitial cells, a multipotent and rapidly cycling stem cell lineage of hydra, express higher levels of XPF mRNA than other cell types. Our data show that XPF and by extension, the NER pathway is highly conserved during evolution. The prominent expression of an NER gene in interstitial cells may have implications for the lack of senescence in hydra.

The endoderm indirectly influences morphogenetic movements of the zebrafish head kidney through the posterior cardinal vein and VegfC.

PubMed

Chou, Chih-Wei; Hsu, Hsiao-Chu; You, May-Su; Lin, Jamie; Liu, Yi-Wen

2016-08-01

Integration of blood vessels and organ primordia determines organ shape and function. The head kidney in the zebrafish interacts with the dorsal aorta (DA) and the posterior cardinal vein (PCV) to achieve glomerular filtration and definitive hematopoiesis, respectively. How the head kidney co-develops with both the axial artery and vein remains unclear. We found that in endodermless sox32-deficient embryos, the head kidney associated with the PCV but not the DA. Disrupted convergent migration of the PCV and the head kidney in sox32-deficient embryos was rescued in a highly coordinated fashion through the restoration of endodermal cells. Moreover, grafted endodermal cells abutted the host PCV endothelium in the transplantation assay. Interestingly, the severely-disrupted head kidney convergence in the sox32-deficient embryo was suppressed by both the cloche mutation and the knockdown of endothelial genes, indicating that an interaction between the endoderm and the PCV restricts the migration of the head kidney. Furthermore, knockdown of either vegfC or its receptor vegfr3 suppressed the head kidney convergence defect in endodermless embryos and perturbed the head kidney-PCV association in wild-type embryos. Our findings thus underscore a role for PCV and VegfC in patterning the head kidney prior to organ assembly and function.

Genetic analysis of the role of amyloplasts in shoot gravisensing

NASA Astrophysics Data System (ADS)

Tasaka, M.; Morita, M.

Plant can change the growth direction after sensing the gravity orientation This response calls gravitropism and the initial step is the gravisensing We have isolated many Arabidopsis mutants shoot gravitropism sgr with reduced or no gravitropic response in inflorescence stems The analysis of sgr1 and sgr7 revealed that endoderm cells in the inflorescence stems were gravisensing sites zig zigzag sgr4 and sgr3 showed no or reduced gravitropism in shoot respectively and their amyloplasts thought to be statoliths did not sedimented to the orientation of gravity in the endoderm cells ZIG encoded a SNARE AtVTI11 and SGR3 encoded other SNARE AtVAM3 These two SNAREs made a complex in the shoot endoderm cells suggesting that the vesicle transport from trans-Golgi network TGN to prevacuolar compartment PVC and or vacuole was involved in the amyloplasts localization and movement The analysis to visualize amyloplasts and vacuolar membrane in living endoderm cells supported that the vacuole function was important for the amyloplasts movement Recently we have isolated many suppressor mutants of zig One of them named zig suppressor zip 1 had a point mutation in the gene encoded other SNARE of AtVTI12 This protein is a homologous to ZIG AtVTI11 and these two proteins have partially redundant functions Although wild type At VTI 12 could not rescued zig mutated AtVTI12 protein ZIP1 could almost completely play the part of ZIG In zigzip1 amyloplasts in endoderm cells sedimented normally and the shoots showed normal gravitropic response The other

Stem cell system in asexual and sexual reproduction of Enchytraeus japonensis (Oligochaeta, Annelida).

PubMed

Yoshida-Noro, Chikako; Tochinai, Shin

2010-01-01

Enchytraeus japonensis is a small oligochaete species that proliferates asexually via fragmentation and regeneration. As sexual reproduction can also be induced, it is a good model system for the study of both regenerative and germline stem cells. It has been shown by histological study that putative mesodermal stem cells called neoblasts, and dedifferentiated epidermal and endodermal cells are involved in blastema formation. Recently, we isolated three region-specific marker genes expressed in the digestive tract and showed by in situ hybridization that morphallactic as well as epimorphic regulation of the body patterning occurs during regeneration. We also cloned two vasa-related genes and analyzed their expression during development and in mature worms that undergo sexual reproduction. The results arising form these studies suggest that the origin and development of germline stem cells and neoblasts may be independent. Furthermore, we carried out functional analysis using RNA interference (RNAi) and showed that a novel gene termed grimp is required for mesodermal cell proliferation at the initial stages of regeneration. These findings indicate that the stem cell system in E. japonensis is regulated by both internal and external environmental factors.

Dynamic changes in Sox2 spatio-temporal expression promote the second cell fate decision through Fgf4/Fgfr2 signaling in preimplantation mouse embryos.

PubMed

Mistri, Tapan Kumar; Arindrarto, Wibowo; Ng, Wei Ping; Wang, Choayang; Lim, Leng Hiong; Sun, Lili; Chambers, Ian; Wohland, Thorsten; Robson, Paul

2018-03-20

Oct4 and Sox2 regulate the expression of target genes such as Nanog, Fgf4 , and Utf1 , by binding to their respective regulatory motifs. Their functional cooperation is reflected in their ability to heterodimerize on adjacent cis regulatory motifs, the composite Sox/Oct motif. Given that Oct4 and Sox2 regulate many developmental genes, a quantitative analysis of their synergistic action on different Sox/Oct motifs would yield valuable insights into the mechanisms of early embryonic development. In the present study, we measured binding affinities of Oct4 and Sox2 to different Sox/Oct motifs using fluorescence correlation spectroscopy. We found that the synergistic binding interaction is driven mainly by the level of Sox2 in the case of the Fgf4 Sox/Oct motif. Taking into account Sox2 expression levels fluctuate more than Oct4 , our finding provides an explanation on how Sox2 controls the segregation of the epiblast and primitive endoderm populations within the inner cell mass of the developing rodent blastocyst. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The lateral mesodermal divide: an epigenetic model of the origin of paired fins.

PubMed

Nuño de la Rosa, Laura; Müller, Gerd B; Metscher, Brian D

2014-01-01

By examining development at the level of tissues and processes, rather than focusing on gene expression, we have formulated a general hypothesis to explain the dorso-ventral and anterior-posterior placement of paired appendage initiation sites in vertebrates. According to our model, the number and position of paired appendages are due to a commonality of embryonic tissue environments determined by the global interactions involving the two separated layers (somatic and visceral) of lateral plate mesoderm along the dorso-ventral and anterior-posterior axes of the embryo. We identify this distribution of developmental conditions, as modulated by the separation/contact of the two LPM layers and their interactions with somitic mesoderm, ectoderm, and endoderm as a dynamic developmental entity which we have termed the lateral mesodermal divide (LMD). Where the divide results in a certain tissue environment, fin bud initiation can occur. According to our hypothesis, the influence of the developing gut suppresses limb initiation along the midgut region and the ventral body wall owing to an "endodermal predominance." From an evolutionary perspective, the lack of gut regionalization in agnathans reflects the ancestral absence of these conditions, and the elaboration of the gut together with the concomitant changes to the LMD in the gnathostomes could have led to the origin of paired fins. © 2013 Wiley Periodicals, Inc.

Generation of knock-in mice that express nuclear enhanced green fluorescent protein and tamoxifen-inducible Cre recombinase in the notochord from Foxa2 and T loci.

PubMed

Imuta, Yu; Kiyonari, Hiroshi; Jang, Chuan-Wei; Behringer, Richard R; Sasaki, Hiroshi

2013-03-01

The node and the notochord are important embryonic signaling centers that control embryonic pattern formation. Notochord progenitor cells present in the node and later in the posterior end of the notochord move anteriorly to generate the notochord. To understand the dynamics of cell movement during notochord development and the molecular mechanisms controlling this event, analyses of cell movements using time-lapse imaging and conditional manipulation of gene activities are required. To achieve this goal, we generated two knock-in mouse lines that simultaneously express nuclear enhanced green fluorescent protein (EGFP) and tamoxifen-inducible Cre, CreER(T2) , from two notochord gene loci, Foxa2 and T (Brachury). In Foxa2(nEGFP-CreERT2/+) and T(nEGFP-CreERT2/+) embryos, nuclei of the Foxa2 or T-expressing cells, which include the node, notochord, and endoderm (Foxa2) or wide range of posterior mesoderm (T), were labeled with EGFP at intensities that can be used for live imaging. Cre activity was also induced in cells expressing Foxa2 and T 1 day after tamoxifen administration. These mice are expected to be useful tools for analyzing the mechanisms of notochord development. Copyright © 2013 Wiley Periodicals, Inc.

Epidermal Phytochrome B Inhibits Hypocotyl Negative Gravitropism Non-Cell-Autonomously.

PubMed

Kim, Jaewook; Song, Kijong; Park, Eunae; Kim, Keunhwa; Bae, Gabyong; Choi, Giltsu

2016-11-01

Seedling hypocotyls display negative gravitropism in the dark but agravitropism in the light. The Arabidopsis thaliana pif quadruple mutant (pifQ), which lacks four PHYTOCHROME-INTERACTING FACTORS (PIFs), is agravitropic in the dark. Endodermis-specific expression of PIF1 rescues gravitropism in pifQ mutant seedlings. Since phytochromes induce light responses by inhibiting PIFs and the COP1-SPA ubiquitin E3 ligase complex in the nucleus, we asked whether phyB can cell autonomously inhibit hypocotyl negative gravitropism in the endodermis. We found that while epidermis-specific expression of PHYB rescues hypocotyl negative gravitropism and all other phyB mutant phenotypes, endodermis-specific expression of PHYB does not. Epidermal phyB induces the phosphorylation and degradation of endodermal PIFs in response to red light. This induces a global gene expression pattern similar to that induced by red light treatment of seedlings expressing PHYB under the control of its own endogenous promoter. Our results imply that epidermal phyB generates an unidentified mobile signal that travels to the endodermis where it promotes PIF degradation and inhibits hypocotyl negative gravitropism. © 2016 American Society of Plant Biologists. All rights reserved.

Epidermal Phytochrome B Inhibits Hypocotyl Negative Gravitropism Non-Cell-Autonomously

PubMed Central

Kim, Jaewook; Song, Kijong; Park, Eunae; Kim, Keunhwa; Choi, Giltsu

2016-01-01

Seedling hypocotyls display negative gravitropism in the dark but agravitropism in the light. The Arabidopsis thaliana pif quadruple mutant (pifQ), which lacks four PHYTOCHROME-INTERACTING FACTORS (PIFs), is agravitropic in the dark. Endodermis-specific expression of PIF1 rescues gravitropism in pifQ mutant seedlings. Since phytochromes induce light responses by inhibiting PIFs and the COP1-SPA ubiquitin E3 ligase complex in the nucleus, we asked whether phyB can cell autonomously inhibit hypocotyl negative gravitropism in the endodermis. We found that while epidermis-specific expression of PHYB rescues hypocotyl negative gravitropism and all other phyB mutant phenotypes, endodermis-specific expression of PHYB does not. Epidermal phyB induces the phosphorylation and degradation of endodermal PIFs in response to red light. This induces a global gene expression pattern similar to that induced by red light treatment of seedlings expressing PHYB under the control of its own endogenous promoter. Our results imply that epidermal phyB generates an unidentified mobile signal that travels to the endodermis where it promotes PIF degradation and inhibits hypocotyl negative gravitropism. PMID:27758895

Intrinsic and Extrinsic Modifiers of the Regulative Capacity of the Developing Liver

PubMed Central

Shin, Donghun; Weidinger, Gilbert; Moon, Randall T.; Stainier, Didier Y.R.

2012-01-01

Zebrafish wnt2bb mutants initially fail to form a liver, but surprisingly the liver eventually forms in a majority of these embryos which then develop into fertile adults. This unexpected result raised the possibility that identifying the mechanisms of liver formation in wnt2bb mutants could provide insights into the poorly understood yet general principle of regulative development, a process by which some cells can change fate in order to compensate for a deficiency. Here, we identify two factors that underlie the regulative capacity of endodermal tissues: an intrinsic factor, Sox32, a transcription factor of the SoxF subfamily, and an extrinsic factor, Fgf10a. sox32 is expressed in the extrahepatic duct primordium which is not affected in wnt2bb mutants. Blocking Sox32 function prevented liver formation in most wnt2bb mutants. fgf10a, which is expressed in the mesenchyme surrounding non-hepatic endodermal cells, negatively impacts the regulative capacity of endodermal tissues. In Wnt/β-catenin signaling deficient embryos, in which the liver completely fails to form, the repression of Fgf10a function allowed liver formation. Altogether, these studies reveal that there is more than one way to form a liver, and provide molecular insights into the phenomenon of tissue plasticity. PMID:22313811

Dynamics of genomic H3K27me3 domains and role of EZH2 during pancreatic endocrine specification

PubMed Central

Xu, Cheng-Ran; Li, Lin-Chen; Donahue, Greg; Ying, Lei; Zhang, Yu-Wei; Gadue, Paul; Zaret, Kenneth S

2014-01-01

Endoderm cells undergo sequential fate choices to generate insulin-secreting beta cells. Ezh2 of the PRC2 complex, which generates H3K27me3, modulates the transition from endoderm to pancreas progenitors, but the role of Ezh2 and H3K27me3 in the next transition to endocrine progenitors is unknown. We isolated endoderm cells, pancreas progenitors, and endocrine progenitors from different staged mouse embryos and analyzed H3K27me3 genome-wide. Unlike the decline in H3K27me3 domains reported during embryonic stem cell differentiation in vitro, we find that H3K27me3 domains increase in number during endocrine progenitor development in vivo. Genes that lose the H3K27me3 mark typically encode transcriptional regulators, including those for pro-endocrine fates, whereas genes that acquire the mark typically are involved in cell biology and morphogenesis. Deletion of Ezh2 at the pancreas progenitor stage enhanced the production of endocrine progenitors and beta cells. Inhibition of EZH2 in embryonic pancreas explants and in human embryonic stem cell cultures increased endocrine progenitors in vitro. Our studies reveal distinct dynamics in H3K27me3 targets in vivo and a means to modulate beta cell development from stem cells. PMID:25107471

A peptide hormone required for Casparian strip diffusion barrier formation in Arabidopsis roots.

PubMed

Nakayama, Takuya; Shinohara, Hidefumi; Tanaka, Mina; Baba, Koki; Ogawa-Ohnishi, Mari; Matsubayashi, Yoshikatsu

2017-01-20

Plants achieve mineral ion homeostasis by means of a hydrophobic barrier on endodermal cells called the Casparian strip, which restricts lateral diffusion of ions between the root vascular bundles and the soil. We identified a family of sulfated peptides required for contiguous Casparian strip formation in Arabidopsis roots. These peptide hormones, which we named Casparian strip integrity factor 1 (CIF1) and CIF2, are expressed in the root stele and specifically bind the endodermis-expressed leucine-rich repeat receptor kinase GASSHO1 (GSO1)/SCHENGEN3 and its homolog, GSO2. A mutant devoid of CIF peptides is defective in ion homeostasis in the xylem. CIF genes are environmentally responsive. Casparian strip regulation is not merely a passive process driven by root developmental cues; it also serves as an active strategy to cope with adverse soil conditions. Copyright © 2017, American Association for the Advancement of Science.

Gut endoderm takes flight from the wings of mesoderm.

PubMed

McDonald, Angela C H; Rossant, Janet

2014-12-01

The endoderm layer destined to be primitive gut is a mosaic of earlier visceral endoderm and definitive endoderm that arises later, during gastrulation. Live imaging now reveals that in mouse embryos, definitive endoderm cells egress from underlying mesoderm and intercalate into the overlying cell layer. This process requires SOX17-mediated control of basement membrane organization.

Aryl hydrocarbon receptor (AHR) in the cnidarian Nematostella vectensis: comparative expression, protein interactions, and ligand binding.

PubMed

Reitzel, Adam M; Passamaneck, Yale J; Karchner, Sibel I; Franks, Diana G; Martindale, Mark Q; Tarrant, Ann M; Hahn, Mark E

2014-02-01

The aryl hydrocarbon receptor (AHR) is a member of the basic helix-loop-helix/Per-ARNT-Sim (bHLH-PAS) family of transcription factors and has diverse roles in development, physiology, and environmental sensing in bilaterian animals. Studying the expression of conserved genes and function of proteins in outgroups to protostomes and deuterostomes assists in understanding the antiquity of gene function and deciphering lineage-specific differences in these bilaterian clades. We describe the developmental expression of AHR from the sea anemone Nematostella vectensis and compare its expression with three other members of the bHLH-PAS family (AHR nuclear translocator (ARNT), Cycle, and a proto-Single-Minded/Trachealess). NvAHR expression was highest early in the larval stage with spatial expression in the basal portion of the ectoderm that became increasingly restricted to the oral pole with concentrated expression in tentacles of the juvenile polyp. The other bHLH-PAS genes showed a divergent expression pattern in later larval stages and polyps, in which gene expression was concentrated in the aboral end, with broader expression in the endoderm later in development. In co-immunoprecipitation assays, we found no evidence for heterodimerization of AHR with ARNT, contrary to the conservation of this specific interaction in all bilaterians studied to date. Similar to results with other invertebrate AHRs but in contrast to vertebrate AHRs, NvAHR failed to bind two prototypical xenobiotic AHR ligands (2,3,7,8-tetrachlorodibenzo-p-dioxin, β-naphthoflavone). Together, our data suggest that AHR's original function in Eumetazoa likely involved developmental patterning, potentially of neural tissue. The role of heterodimerization in the function of AHR may have arisen after the cnidarian-bilaterian ancestor. The absence of xenobiotic binding to NvAHR further supports a hypothesis for a derived role of this protein in chemical sensing within the chordates.

Aryl hydrocarbon receptor (AHR) in the cnidarian Nematostella vectensis: comparative expression, protein interactions, and ligand binding

PubMed Central

Reitzel, Adam M.; Passamaneck, Yale J.; Karchner, Sibel I.; Franks, Diana G.; Martindale, Mark Q.; Tarrant, Ann M.; Hahn, Mark E.

2014-01-01

The aryl hydrocarbon receptor (AHR) is a member of the basic-helix-loop-helix/Per-ARNT-Sim (bHLH-PAS) family of transcription factors and has diverse roles in development, physiology, and environmental sensing in bilaterian animals. Studying the expression of conserved genes and function of proteins in outgroups to protostomes and deuterostomes assists in understanding the antiquity of gene function and deciphering lineage-specific differences in these bilaterian clades. We describe the developmental expression of AHR from the sea anemone Nematostella vectensis and compare its expression with three other members of the bHLH-PAS family (AHR nuclear translocator (ARNT), Cycle, and a proto-Single-Minded/Trachaeless). NvAHR expression was highest early in the larval stage with spatial expression in the basal portion of the ectoderm that became increasingly restricted to the oral pole with concentrated expression in tentacles of the juvenile polyp. The other bHLH-PAS genes showed a divergent expression pattern in later larval stages and polyps, in which gene expression was concentrated in the aboral end, with broader expression in the endoderm later in development. In co-immunoprecipitation assays, we found no evidence for heterodimerization of AHR with ARNT, contrary to the conservation of this specific interaction in all bilaterians studied to date. Similar to results with other invertebrate AHRs but in contrast to vertebrate AHRs, NvAHR failed to bind two prototypical xenobiotic AHR ligands (TCDD, BNF). Together, our data suggest that AHR's original function in Eumetazoa likely involved developmental patterning, potentially of neural tissue. The role of heterodimerization in the function of AHR may have arisen after the cnidarian-bilaterian ancestor. The absence of xenobiotic binding to NvAHR further supports a hypothesis for a derived role of this protein in chemical sensing within the chordates. PMID:24292160

Equivalency of Buffalo (Bubalus Bubalis) Embryonic Stem Cells Derived From Fertilized, Parthenogenetic, and Hand-Made Cloned Embryos

PubMed Central

Muzaffar, Musharifa; Selokar, Naresh L.; Singh, Karn P.; Zandi, Mohammad; Singh, Manoj K.; Shah, Riaz A.; Chauhan, Manmohan S.; Singla, Suresh K.; Palta, Prabhat

2012-01-01

Abstract This study was aimed at establishing buffalo embryonic stem cells (ESCs) from in vitro fertilized (IVF), parthenogenetic, and hand-made cloned (HMC) embryos and to check their equivalency in terms of stem cell marker expression, longevity, proliferation, and differentiation pattern. ESCs derived from all three sources were found by immunofluorescence to express the pluripotency markers SSEA-4, TRA-1-60, TRA-1-81, OCT4, and SOX2 and were able to form embryoid bodies containing cells expressing genes specific to endoderm (AFP, HNF4, and GATA4), mesoderm (MSX1, BMP4, and ASA), and ectoderm (cytokeratin 8 and NF68). Reverse transcriptase PCR (RT-PCR) showed cells from all sources to be positive for pluripotency markers OCT4, SOX2, NANOG, STAT3, REX1, FOXD3, NUCLEOSTEMIN, and TELOMERASE. Pluripotency markers OCT4, SOX2, NANOG, and c-MYC were also analyzed by real-time PCR. No significant differences were observed among ESCs from all three sources for all these genes except NANOG, whose expression was higher (p<0.05) in HMC-derived ESCs (6.897±2.3) compared to that in parthenogenesis- and IVF-derived cells (1.603±0.315 and 1±0, respectively). Pluripotent, stable buffalo ESC lines derived from IVF, parthenogenesis, and HMC embryos may be genetically manipulated to provide a powerful tool for studies involving embryonic development, genomic imprinting, gene targeting, cloning, chimera formation, and transgenic animal production. PMID:22582863

Equivalency of buffalo (Bubalus bubalis) embryonic stem cells derived from fertilized, parthenogenetic, and hand-made cloned embryos.

PubMed

Muzaffar, Musharifa; Selokar, Naresh L; Singh, Karn P; Zandi, Mohammad; Singh, Manoj K; Shah, Riaz A; Chauhan, Manmohan S; Singla, Suresh K; Palta, Prabhat; Manik, Radheysham

2012-06-01

This study was aimed at establishing buffalo embryonic stem cells (ESCs) from in vitro fertilized (IVF), parthenogenetic, and hand-made cloned (HMC) embryos and to check their equivalency in terms of stem cell marker expression, longevity, proliferation, and differentiation pattern. ESCs derived from all three sources were found by immunofluorescence to express the pluripotency markers SSEA-4, TRA-1-60, TRA-1-81, OCT4, and SOX2 and were able to form embryoid bodies containing cells expressing genes specific to endoderm (AFP, HNF4, and GATA4), mesoderm (MSX1, BMP4, and ASA), and ectoderm (cytokeratin 8 and NF68). Reverse transcriptase PCR (RT-PCR) showed cells from all sources to be positive for pluripotency markers OCT4, SOX2, NANOG, STAT3, REX1, FOXD3, NUCLEOSTEMIN, and TELOMERASE. Pluripotency markers OCT4, SOX2, NANOG, and c-MYC were also analyzed by real-time PCR. No significant differences were observed among ESCs from all three sources for all these genes except NANOG, whose expression was higher (p<0.05) in HMC-derived ESCs (6.897±2.3) compared to that in parthenogenesis- and IVF-derived cells (1.603±0.315 and 1±0, respectively). Pluripotent, stable buffalo ESC lines derived from IVF, parthenogenesis, and HMC embryos may be genetically manipulated to provide a powerful tool for studies involving embryonic development, genomic imprinting, gene targeting, cloning, chimera formation, and transgenic animal production.

The alpha1-fetoprotein locus is activated by a nuclear receptor of the Drosophila FTZ-F1 family.

PubMed

Galarneau, L; Paré, J F; Allard, D; Hamel, D; Levesque, L; Tugwood, J D; Green, S; Bélanger, L

1996-07-01

The alpha1-fetoprotein (AFP) gene is located between the albumin and alpha-albumin genes and is activated by transcription factor FTF (fetoprotein transcription factor), presumed to transduce early developmental signals to the albumin gene cluster. We have identified FTF as an orphan nuclear receptor of the Drosophila FTZ-F1 family. FTF recognizes the DNA sequence 5'-TCAAGGTCA-3', the canonical recognition motif for FTZ-F1 receptors. cDNA sequence homologies indicate that rat FTF is the ortholog of mouse LRH-1 and Xenopus xFF1rA. Rodent FTF is encoded by a single-copy gene, related to the gene encoding steroidogenic factor 1 (SF-1). The 5.2-kb FTF transcript is translated from several in-frame initiator codons into FTF isoforms (54 to 64 kDa) which appear to bind DNA as monomers, with no need for a specific ligand, similar KdS (approximately equal 3 x 10(-10) M), and similar transcriptional effects. FTF activates the AFP promoter without the use of an amino-terminal activation domain; carboxy-terminus-truncated FTF exerts strong dominant negative effects. In the AFP promoter, FTF recruits an accessory trans-activator which imparts glucocorticoid reactivity upon the AFP gene. FTF binding sites are found in the promoters of other liver-expressed genes, some encoding liver transcription factors; FTF, liver alpha1-antitrypsin promoter factor LFB2, and HNF-3beta promoter factor UF2-H3beta are probably the same factor. FTF is also abundantly expressed in the pancreas and may exert differentiation functions in endodermal sublineages, similar to SF-1 in steroidogenic tissues. HepG2 hepatoma cells seem to express a mutated form of FTF.

Identification and characterization of VEGF and FGF from Hydra.

PubMed

Krishnapati, Lakshmi-Surekha; Ghaskadbi, Surendra

2013-01-01

Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) play important roles in the formation of the blood vascular system and in axon guidance, nervous system development and function. Here, we report isolation and characterization of VEGF and FGF homologues from Hydra vulgaris Ind-Pune, a Cnidarian which exhibits an organized nervous system and primitive epithelio-muscular cells. VEGF expression was prominent in the endoderm of the peduncle region and tentacles, as evident from in situ hybridization of whole polyps and its transverse sections. High levels of FGF were detected in the ectoderm of the budding region. The expression of VEGF in endodermal and FGF in interstitial cells was confirmed using sf-1 hydra, a temperature-sensitive mutant strain of Hydra magnipapillata. Tissue-specific expression of VEGF and FGF was confirmed by semi quantitative RT-PCR for ectodermal and endodermal tissues in H. vulgaris Ind-Pune. Treatment with SU5416, a specific inhibitor of the VEGF receptor, did not affect the whole polyp, but did delay both budding and head regeneration, suggesting a possible role of VEGF in nerve cell development, tube formation and/or in branching. FGF expression in the ectoderm of budding region, where the majority of interstitial stem cells reside suggests its role in interstitial stem cell maintenance. Further, activation of canonical Wnt signalling with the glycogen synthase kinase-3β (GSK-3β) inhibitor alsterpaullone caused down-regulation of VEGF and FGF, suggesting an antagonistic relationship between the Wnt and VEGF/FGF pathways. Our results indicate that VEGF and FGF evolved early in evolution, before the development of the blood vascular system, and open up the possibility of elucidating the evolutionarily ancient functions of VEGF and FGF.

Developmental gene regulatory network architecture across 500 million years of echinoderm evolution

NASA Technical Reports Server (NTRS)

Hinman, Veronica F.; Nguyen, Albert T.; Cameron, R. Andrew; Davidson, Eric H.

2003-01-01

Evolutionary change in morphological features must depend on architectural reorganization of developmental gene regulatory networks (GRNs), just as true conservation of morphological features must imply retention of ancestral developmental GRN features. Key elements of the provisional GRN for embryonic endomesoderm development in the sea urchin are here compared with those operating in embryos of a distantly related echinoderm, a starfish. These animals diverged from their common ancestor 520-480 million years ago. Their endomesodermal fate maps are similar, except that sea urchins generate a skeletogenic cell lineage that produces a prominent skeleton lacking entirely in starfish larvae. A relevant set of regulatory genes was isolated from the starfish Asterina miniata, their expression patterns determined, and effects on the other genes of perturbing the expression of each were demonstrated. A three-gene feedback loop that is a fundamental feature of the sea urchin GRN for endoderm specification is found in almost identical form in the starfish: a detailed element of GRN architecture has been retained since the Cambrian Period in both echinoderm lineages. The significance of this retention is highlighted by the observation of numerous specific differences in the GRN connections as well. A regulatory gene used to drive skeletogenesis in the sea urchin is used entirely differently in the starfish, where it responds to endomesodermal inputs that do not affect it in the sea urchin embryo. Evolutionary changes in the GRNs since divergence are limited sharply to certain cis-regulatory elements, whereas others have persisted unaltered.

Insights into islet development and biology through characterization of a human iPSC-derived endocrine pancreas model

PubMed Central

van de Bunt, Martijn; Lako, Majlinda; Barrett, Amy; Gloyn, Anna L.; Hansson, Mattias; McCarthy, Mark I.; Honoré, Christian

2016-01-01

ABSTRACT Directed differentiation of stem cells offers a scalable solution to the need for human cell models recapitulating islet biology and T2D pathogenesis. We profiled mRNA expression at 6 stages of an induced pluripotent stem cell (iPSC) model of endocrine pancreas development from 2 donors, and characterized the distinct transcriptomic profiles associated with each stage. Established regulators of endodermal lineage commitment, such as SOX17 (log2 fold change [FC] compared to iPSCs = 14.2, p-value = 4.9 × 10−5) and the pancreatic agenesis gene GATA6 (log2 FC = 12.1, p-value = 8.6 × 10−5), showed transcriptional variation consistent with their known developmental roles. However, these analyses highlighted many other genes with stage-specific expression patterns, some of which may be novel drivers or markers of islet development. For example, the leptin receptor gene, LEPR, was most highly expressed in published data from in vivo-matured cells compared to our endocrine pancreas-like cells (log2 FC = 5.5, p-value = 2.0 × 10−12), suggesting a role for the leptin pathway in the maturation process. Endocrine pancreas-like cells showed significant stage-selective expression of adult islet genes, including INS, ABCC8, and GLP1R, and enrichment of relevant GO-terms (e.g. “insulin secretion”; odds ratio = 4.2, p-value = 1.9 × 10−3): however, principal component analysis indicated that in vitro-differentiated cells were more immature than adult islets. Integration of the stage-specific expression information with genetic data from T2D genome-wide association studies revealed that 46 of 82 T2D-associated loci harbor genes present in at least one developmental stage, facilitating refinement of potential effector transcripts. Together, these data show that expression profiling in an iPSC islet development model can further understanding of islet biology and T2D pathogenesis. PMID:27246810

Inactivation of the Huntington's disease gene (Hdh) impairs anterior streak formation and early patterning of the mouse embryo

PubMed Central

Woda, Juliana M; Calzonetti, Teresa; Hilditch-Maguire, Paige; Duyao, Mabel P; Conlon, Ronald A; MacDonald, Marcy E

2005-01-01

Background Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdhex4/5 huntingtin deficient embryos. Results In the absence of huntingtin, expression of nutritive genes appears normal but E7.0–7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury) and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE) are specified. Conclusion Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in Huntington's disease. PMID:16109169

DIDO as a Switchboard that Regulates Self-Renewal and Differentiation in Embryonic Stem Cells.

PubMed

Fütterer, Agnes; de Celis, Jésus; Navajas, Rosana; Almonacid, Luis; Gutiérrez, Julio; Talavera-Gutiérrez, Amaia; Pacios-Bras, Cristina; Bernascone, Ilenia; Martin-Belmonte, Fernando; Martinéz-A, Carlos

2017-04-11

Transition from symmetric to asymmetric cell division requires precise coordination of differential gene expression. We show that embryonic stem cells (ESCs) mainly express DIDO3 and that their differentiation after leukemia inhibitory factor withdrawal requires DIDO1 expression. C-terminal truncation of DIDO3 (Dido3ΔCT) impedes ESC differentiation while retaining self-renewal; small hairpin RNA-Dido1 ESCs have the same phenotype. Dido3ΔCT ESC differentiation is rescued by ectopic expression of DIDO3, which binds the Dido locus via H3K4me3 and RNA POL II and induces DIDO1 expression. DIDO1, which is exported to cytoplasm, associates with, and is N-terminally phosphorylated by PKCiota. It binds the E3 ubiquitin ligase WWP2, which contributes to cell fate by OCT4 degradation, to allow expression of primitive endoderm (PE) markers. PE formation also depends on phosphorylated DIDO3 localization to centrosomes, which ensures their correct positioning for PE cell polarization. We propose that DIDO isoforms act as a switchboard that regulates genetic programs for ESC transition from pluripotency maintenance to promotion of differentiation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Effect of 3D Cultivation Conditions on the Differentiation of Endodermal Cells

PubMed Central

Petrakova, O. S.; Ashapkin, V. V.; Voroteliak, E. A.; Bragin, E. Y.; Shtratnikova, V. Y.; Chernioglo, E. S.; Sukhanov, Y. V.; Terskikh, V. V.; Vasiliev, A. V.

2012-01-01

Cellular therapy of endodermal organs is one of the most important issues in modern cellular biology and biotechnology. One of the most promising directions in this field is the study of the transdifferentiation abilities of cells within the same germ layer. A method for anin vitroinvestigation of the cell differentiation potential (the cell culture in a three-dimensional matrix) is described in this article. Cell cultures of postnatal salivary gland cells and postnatal liver progenitor cells were obtained; their comparative analysis under 2D and 3D cultivation conditions was carried out. Both cell types have high proliferative abilities and can be cultivated for more than 20 passages. Under 2D cultivation conditions, the cells remain in an undifferentiated state. Under 3D conditions, they undergo differentiation, which was confirmed by a lower cell proliferation and by an increase in the differentiation marker expression. Salivary gland cells can undergo hepatic and pancreatic differentiation under 3D cultivation conditions. Liver progenitor cells also acquire a pancreatic differentiation capability under conditions of 3D cultivation. Thus, postnatal salivary gland cells exhibit a considerable differentiation potential within the endodermal germ layer and can be used as a promising source of endodermal cells for the cellular therapy of liver pathologies. Cultivation of cells under 3D conditions is a useful model for thein vitroanalysis of the cell differentiation potential. PMID:23346379

Correct Patterning of the Primitive Streak Requires the Anterior Visceral Endoderm

PubMed Central

Stuckey, Daniel W.; Di Gregorio, Aida; Clements, Melanie; Rodriguez, Tristan A.

2011-01-01

Anterior-posterior axis specification in the mouse requires signalling from a specialised extra-embryonic tissue called the anterior visceral endoderm (AVE). AVE precursors are induced at the distal tip of the embryo and move to the prospective anterior. Embryological and genetic analysis has demonstrated that the AVE is required for anterior patterning and for correctly positioning the site of primitive streak formation by inhibiting Nodal activity. We have carried out a genetic ablation of the Hex-expressing cells of the AVE (Hex-AVE) by knocking the Diphtheria toxin subunit A into the Hex locus in an inducible manner. Using this model we have identified that, in addition to its requirement in the anterior of the embryo, the Hex-AVE sub-population has a novel role between 5.5 and 6.5dpc in patterning the primitive streak. Embryos lacking the Hex-AVE display delayed initiation of primitive streak formation and miss-patterning of the anterior primitive streak. We demonstrate that in the absence of the Hex-AVE the restriction of Bmp2 expression to the proximal visceral endoderm is also defective and expression of Wnt3 and Nodal is not correctly restricted to the posterior epiblast. These results, coupled with the observation that reducing Nodal signalling in Hex-AVE ablated embryos increases the frequency of phenotypes observed, suggests that these primitive streak patterning defects are due to defective Nodal signalling. Together, our experiments demonstrate that the AVE is not only required for anterior patterning, but also that specific sub-populations of this tissue are required to pattern the posterior of the embryo. PMID:21445260

Morphology, histochemistry and glycosylation of the placenta and associated tissues in the European hedgehog (Erinaceus europaeus).

PubMed

Jones, Carolyn J P; Carter, A M; Allen, W R; Wilsher, Sandra A

2016-12-01

There are few descriptions of the placenta and associated tissues of the European hedgehog (Erinaceus europaeus) and here we present findings on a near-term pregnant specimen. Tissues were examined grossly and then formalin fixed and wax-embedded for histology and immunocytochemistry (cytokeratin) and resin embedded for lectin histochemistry. Each of four well-developed and near term hoglets displayed a discoid, haemochorial placenta with typical labyrinth and spongy zones. In addition there was a paraplacenta incorporating Reichert's membrane and a largely detached yolk sac. The trophoblast of the placenta contained diverse populations of granule which expressed most classes of glycan. Intercellular membranes were also glycosylated and this tended to be heavier in the labyrinth zone. Fetal capillary endothelium had glycosylated apical surfaces expressing sialic acid and various other glycans. Glycogen was present in large cells situated between the spongy zone and the endometrium. Trophoblast cells in the placental disc and under Reichert's membrane, as well as yolk sac endoderm and mesothelium, were cytokeratin positive. Reichert's membrane was heavily glycosylated. Yolk sac inner and outer endoderm expressed similar glycans except for N-acetylgalactosamine residues in endodermal acini. New features of near-term hedgehog placenta and associated tissues are presented, including their glycosylation, and novel yolk sac acinar structures are described. The trophoblast of the placental disc showed significant differences from that underlying Reichert's membrane while the glycan composition of the membrane itself showed some similarity to that of rat thereby implying a degree of biochemical conservation of this structure. Copyright © 2016 Elsevier Ltd. All rights reserved.

ROCK inhibitor Y-27632 enhances the survivability of dissociated buffalo (Bubalus bubalis) embryonic stem cell-like cells.

PubMed

Sharma, Ruchi; George, Aman; Chauhan, Manmohan S; Singla, Suresh; Manik, Radhey S; Palta, Prabhat

2013-01-01

This study investigated the effects of supplementation of culture medium with 10 μM Y-27632, a specific inhibitor of Rho kinase activity, for 6 days on self-renewal of buffalo embryonic stem (ES) cell-like cells at Passage 50-80. Y-27632 increased mean colony area (P<0.05) although it did not improve their survival. It decreased OCT4 expression (P<0.05), increased NANOG expression (P<0.05), but had no effect on SOX2 expression. It also increased expression of anti-apoptotic gene BCL-2 (P<0.05) and decreased that of pro-apoptotic genes BAX and BID (P<0.05). It increased plating efficiency of single-cell suspensions of ES cells (P<0.05). Following vitrification, the presence of Y-27632 in the vitrification solution or thawing medium or both did not improve ES cell colony survival. However, following seeding of clumps of ES cells transfected with pAcGFP1N1 carrying green fluorescent protein (GFP), Y-27632 increased colony formation rate (P<0.01). ES cell colonies that formed in all Y-27632-supplemented groups were confirmed for expression of pluripotency markers alkaline phosphatase, SSEA-4 and TRA-1-60, and for their ability to generate embryoid bodies containing cells that expressed markers of ectoderm, mesoderm and endoderm. In conclusion, Y-27632 improves survival of buffalo ES cells under unfavourable conditions such as enzymatic dissociation to single cells or antibiotic-assisted selection after transfection, without compromising their pluripotency.

Expression patterns of Xenopus FGF receptor-like 1/nou-darake in early Xenopus development resemble those of planarian nou-darake and Xenopus FGF8.

PubMed

Hayashi, Shuichi; Itoh, Mari; Taira, Sumiko; Agata, Kiyokazu; Taira, Masanori

2004-08-01

Fibroblast growth factors (FGFs) mediate many cell-to-cell signaling events during early development. Nou-darake (ndk), a gene encoding an FGF receptor (FGFR)-like molecule, was found to be highly and specifically expressed in the head region of the planarian Dugesia japonica, and its functional analyses provided strong molecular evidence for the existence of a brain-inducing circuit based on the FGF signaling pathway. To analyze the role of ndk during vertebrate development, we isolated the Xenopus ortholog of ndk, the vertebrate FGFR-like 1 gene (XFGFRL1). Expression of XFGFRL1/Xndk was first detected in the anterior region at the late gastrula stage and dramatically increased at the early neurula stage in an overall anterior mesendodermal region, including the prechordal plate, paraxial mesoderm, anterior endoderm, and archenteron roof. This anterior expression pattern resembles that of ndk in planarians, suggesting that the expression of FGFRL1/ndk is conserved in evolution between these two distantly diverged organisms. During the tail bud stages, XFGFRL1/Xndk expression was detected in multiple regions, including the forebrain, eyes, midbrain-hindbrain boundary, otic vesicles, visceral arches, and somites. In many of these regions, XFGFRL1/Xndk was coexpressed with XFGF8, indicating that XFGFRL1/Xndk is a member of the XFGF8 synexpression group, which includes sprouty, sef, and isthmin. Copyright 2004 Wiley-Liss, Inc.

Liver-enriched transcription factors are critical for the expression of hepatocyte marker genes in mES-derived hepatocyte-lineage cells.

PubMed

Kheolamai, Pakpoom; Dickson, Alan J

2009-04-23

Induction of stem cell differentiation toward functional hepatocytes is hampered by lack of knowledge of the hepatocyte differentiation processes. The overall objective of this project is to characterize key stages in the hepatocyte differentiation process. We established a mouse embryonic stem (mES) cell culture system which exhibited changes in gene expression profiles similar to those observed in the development of endodermal and hepatocyte-lineage cells previously described in the normal mouse embryo. Transgenic mES cells were established that permitted isolation of enriched hepatocyte-lineage populations. This approach has isolated mES-derived hepatocyte-lineage cells that express several markers of mature hepatocytes including albumin, glucose-6-phosphatase, tyrosine aminotransferase, cytochrome P450-3a, phosphoenolpyruvate carboxykinase and tryptophan 2,3-dioxygenase. In addition, our results show that the up-regulation of the expression levels of hepatocyte nuclear factor-3alpha, -4alpha, -6, and CCAAT-enhancer binding protein-beta might be critical for passage into late-stage differentiation towards functional hepatocytes. These data present important steps for definition of regulatory phenomena that direct specific cell fate determination. The mES cell culture system generated in this study provides a model for studying transition between stages of the hepatocyte development and has significant potential value for studying the molecular basis of hepatocyte differentiation in vitro.

PITX2 and NODAL expression during axis formation in the early rabbit embryo.

PubMed

Plöger, Ruben; Viebahn, Christoph

2018-04-26

Attaining molecular and morphological axial polarity during gastrulation is a fundamental early requirement for normal development of the embryo. In mammals, the first morphological sign of the anterior-posterior axis appears anteriorly in the form of the anterior marginal crescent (or anterior visceral endoderm) while in the avian the first such sign is the Koller's sickle at the posterior pole of the embryonic disc. Despite this inverse mode of axis formation many genes and molecular pathways involved in various steps of this process seem to be evolutionary conserved amongst amniotes, the nodal gene being a well-known example with its functional involvement prior and during gastrulation. The pitx2 gene, however, is a new candidate described in the chick as an early marker for anterior-posterior polarity and as regulator of axis formation including twinning. To find out whether pitx2 has retained its inductive and early marker function during the evolution of mammals, this study analyzes pitx2 and nodal expression at parallel stages during formation of the anterior-posterior polarity in the early rabbit embryo using whole-mount in situ hybridization and serial light-microscopical sections. At a late pre-gastrulation stage a localized reduction of nodal expression presages the position of the anterior pole of the embryonic disc and thus serves as the earliest molecular marker of anterior-posterior polarity known so far. pitx2 is expressed in a polarized manner in the anterior marginal crescent and in the posterior half of the embryonic disc during further development only while nodal expression in the anterior segment of the posterior pitx2 expression domain helps to define the so-called anterior streak domain (ASD), a novel progenitor region of the anterior half of the primitive streak. The expression patterns of both genes thus serve as signs of a conserved involvement in early axis formation in amniotes and, possibly, in twinning in mammals as well. Copyright © 2018 Elsevier GmbH. All rights reserved.

Generation of Hepatocytes from Pluripotent Stem Cells for Drug Screening and Developmental Modeling.

PubMed

Gieseck, Richard L; Vallier, Ludovic; Hannan, Nicholas R F

2015-01-01

Hepatocytes produced from the differentiation of human pluripotent stem cells can be used to study human development and liver disease, to investigate the toxicological response of novel drug candidates, and as an alternative source of primary cells for transplantation therapies. Here, we describe a method to produce hepatocytes by differentiating human pluripotent stem cells into definitive endoderm, patterning definitive endoderm into anterior definitive endoderm, specifying anterior definitive endoderm into hepatic endoderm, and differentiating hepatic endoderm into immature hepatocytes. These cells are further matured in either two-dimensional or three-dimensional culture conditions to produce cells capable of metabolizing xenobiotics and generating liver-specific proteins, such as albumin and alpha 1 antitrypsin.

Hyperglycemia impedes definitive endoderm differentiation of human embryonic stem cells by modulating histone methylation patterns.

PubMed

Chen, A C H; Lee, Y L; Fong, S W; Wong, C C Y; Ng, E H Y; Yeung, W S B

2017-06-01

Exposure to maternal diabetes during fetal growth is a risk factor for the development of type II diabetes (T2D) in later life. Discovery of the mechanisms involved in this association should provide valuable background for therapeutic treatments. Early embryogenesis involves epigenetic changes including histone modifications. The bivalent histone methylation marks H3K4me3 and H3K27me3 are important for regulating key developmental genes during early fetal pancreas specification. We hypothesized that maternal hyperglycemia disrupted early pancreas development through changes in histone bivalency. A human embryonic stem cell line (VAL3) was used as the cell model for studying the effects of hyperglycemia upon differentiation into definitive endoderm (DE), an early stage of the pancreatic lineage. Hyperglycemic conditions significantly down-regulated the expression levels of DE markers SOX17, FOXA2, CXCR4 and EOMES during differentiation. This was associated with retention of the repressive histone methylation mark H3K27me3 on their promoters under hyperglycemic conditions. The disruption of histone methylation patterns was observed as early as the mesendoderm stage, with Wnt/β-catenin signaling being suppressed during hyperglycemia. Treatment with Wnt/β-catenin signaling activator CHIR-99021 restored the expression levels and chromatin methylation status of DE markers, even in a hyperglycemic environment. The disruption of DE development was also found in mouse embryos at day 7.5 post coitum from diabetic mothers. Furthermore, disruption of DE differentiation in VAL3 cells led to subsequent impairment in pancreatic progenitor formation. Thus, early exposure to hyperglycemic conditions hinders DE development with a possible relationship to the later impairment of pancreas specification.

A null mutation of Hhex results in abnormal cardiac development, defective vasculogenesis and elevated Vegfa levels.

PubMed

Hallaq, Haifa; Pinter, Emese; Enciso, Josephine; McGrath, James; Zeiss, Caroline; Brueckner, Martina; Madri, Joseph; Jacobs, Harris C; Wilson, Christine M; Vasavada, Hemaxi; Jiang, Xiaobing; Bogue, Clifford W

2004-10-01

The homeobox gene Hhex has recently been shown to be essential for normal liver, thyroid and forebrain development. Hhex(-/-) mice die by mid-gestation (E14.5) and the cause of their early demise remains unclear. Because Hhex is expressed in the developing blood islands at E7.0 in the endothelium of the developing vasculature and heart at E9.0-9.5, and in the ventral foregut endoderm at E8.5-9.0, it has been postulated to play a critical role in heart and vascular development. We show here, for the first time, that a null mutation of Hhex results in striking abnormalities of cardiac and vascular development which include: (1) defective vasculogenesis, (2) hypoplasia of the right ventricle, (3) overabundant endocardial cushions accompanied by ventricular septal defects, outflow tract abnormalities and atrio-ventricular (AV) valve dysplasia and (4) aberrant development of the compact myocardium. The dramatic enlargement of the endocardial cushions in the absence of Hhex is due to decreased apoptosis and dysregulated epithelial-mesenchymal transformation (EMT). Interestingly, vascular endothelial growth factor A (Vegfa) levels in the hearts of Hhex(-/-) mice were elevated as much as three-fold between E9.5 and E11.5, and treatment of cultured Hhex(-/-) AV explants with truncated soluble Vegfa receptor 1, sFlt-1, an inhibitor of Vegf signaling, completely abolished the excessive epithelial-mesenchymal transformation seen in the absence of Hhex. Therefore, Hhex expression in the ventral foregut endoderm and/or the endothelium is necessary for normal cardiovascular development in vivo, and one function of Hhex is to repress Vegfa levels during development.

Establishment of human induced pluripotent stem cell lines from normal fibroblast TIG-1.

PubMed

Kumazaki, Tsutomu; Kurata, Sayaka; Matsuo, Taira; Mitsui, Youji; Takahashi, Tomoko

2011-06-01

Normal human cells have a replicative life span and therefore senesce. Usually, normal human cell strains are differentiated cells and reach a terminally differentiated state after a number of cell divisions. At present, definitive differences are not known between replicative senescence and terminal differentiation. TIG-1 is a human fibroblast strain established from fetal lung and has been used extensively in studies of cellular senescence, and numerous data were accumulated at the molecular level. Recently, a method for generating induced pluripotent stem cells (iPSCs) was developed. Using the method, we introduced four reprogramming genes to TIG-1 fibroblasts and succeeded in isolating colonies that had embryonic stem cell (ESC)-like morphologies. They showed alkaline phosphatase activity and expressed ESC markers, as shown by immunostaining of OCT4, SOX2, SSEA4, and TRA-1-81 as well as reverse-transcription polymerase chain reaction (RT-PCR) for OCT4 and NANOG transcripts. Thus, we succeeded in establishing iPSC clones from TIG-1. The iPSC clones could differentiate to cells originated from all three germ-cell layers, as shown by RT-PCR, for messenger RNA (mRNA) expression of α-fetoprotein (endoderm), MSX1 (mesoderm) and microtubule-associated protein 2 (ectoderm), and by immunostaining for α-fetoprotein (endoderm), α-smooth muscle actin (mesoderm), and β-III-tubulin (ectoderm). The iPSCs formed teratoma containing the structures developed from all three germ-cell layers in severe combined immune-deficiency mice. Thus, by comparing the aging process of parental TIG-1 cells and the differentiation process of iPSC-derived fibrocytes to fibroblasts, we can reveal the exact differences in processes between senescence and terminal differentiation.

LIF supports primitive endoderm expansion during pre-implantation development.

PubMed

Morgani, Sophie M; Brickman, Joshua M

2015-10-15

Embryonic stem cells (ESCs) are pluripotent cell lines that can be maintained indefinitely in an early developmental state. ESC culture conditions almost always require the cytokine LIF to maintain self-renewal. As ESCs are not homogeneous but contain multiple populations reminiscent of the blastocyst, identifying the target cells of LIF is necessary to understand the propagation of pluripotency. We recently found that LIF acts under self-renewing conditions to stimulate the fraction of ESCs that express extraembryonic markers, but has little impact on pluripotent gene expression. Here, we report that LIF has two distinct roles: it blocks early epiblast (Epi) differentiation, and it supports the expansion of primitive endoderm (PrE)-primed ESCs and PrE in vivo. We find that activation of JAK/STAT signalling downstream of LIF occurs initially throughout the pre-implantation embryo, but later marks the PrE. Moreover, the addition of LIF to cultured embryos increases the GATA6(+) PrE population, whereas inhibition of JAK/STAT signalling reduces both NANOG(+) epiblast and GATA6(+) PrE. The reduction of the NANOG(+) Epi might be explained by its precocious differentiation to later Epi derivatives, whereas the increase in PrE is mediated both by an increase in proliferation and inhibition of PrE apoptosis that is normally triggered in embryos with an excess of GATA6(+) cells. Thus, it appears that the relative size of the PrE is determined by the number of LIF-producing cells in the embryo. This suggests a mechanism by which the embryo adjusts the relative ratio of the primary lineages in response to experimental manipulation. © 2015. Published by The Company of Biologists Ltd.

Angiomodulin is required for cardiogenesis of embryonic stem cells and is maintained by a feedback loop network of p63 and Activin-A.

PubMed

Wolchinsky, Zohar; Shivtiel, Shoham; Kouwenhoven, Evelyn Nathalie; Putin, Daria; Sprecher, Eli; Zhou, Huiqing; Rouleau, Matthieu; Aberdam, Daniel

2014-01-01

The transcription factor p63, member of the p53 gene family, encodes for two main isoforms, TAp63 and ΔNp63 with distinct functions on epithelial homeostasis and cancer. Recently, we discovered that TAp63 is essential for in vitro cardiogenesis and heart development in vivo. TAp63 is expressed by embryonic endoderm and acts on cardiac progenitors by a cell-non-autonomous manner. In the present study, we search for cardiogenic secreted factors that could be regulated by TAp63 and, by ChIP-seq analysis, identified Angiomodulin (AGM), also named IGFBP7 or IGFBP-rP1. We demonstrate that AGM is necessary for cardiac commitment of embryonic stem cells (ESCs) and its regulation depends on TAp63 isoform. TAp63 directly activates both AGM and Activin-A during ESC cardiogenesis while these secreted factors modulate TAp63 gene expression by a feedback loop mechanism. The molecular circuitry controlled by TAp63 on AGM/Activin-A signaling pathway and thus on cardiogenesis emphasizes the importance of p63 during early cardiac development. © 2013.

Generation of transgenic Hydra by embryo microinjection.

PubMed

Juliano, Celina E; Lin, Haifan; Steele, Robert E

2014-09-11

As a member of the phylum Cnidaria, the sister group to all bilaterians, Hydra can shed light on fundamental biological processes shared among multicellular animals. Hydra is used as a model for the study of regeneration, pattern formation, and stem cells. However, research efforts have been hampered by lack of a reliable method for gene perturbations to study molecular function. The development of transgenic methods has revitalized the study of Hydra biology(1). Transgenic Hydra allow for the tracking of live cells, sorting to yield pure cell populations for biochemical analysis, manipulation of gene function by knockdown and over-expression, and analysis of promoter function. Plasmid DNA injected into early stage embryos randomly integrates into the genome early in development. This results in hatchlings that express transgenes in patches of tissue in one or more of the three lineages (ectodermal epithelial, endodermal epithelial, or interstitial). The success rate of obtaining a hatchling with transgenic tissue is between 10% and 20%. Asexual propagation of the transgenic hatchling is used to establish a uniformly transgenic line in a particular lineage. Generating transgenic Hydra is surprisingly simple and robust, and here we describe a protocol that can be easily implemented at low cost.

Divergent functions of fibroblast growth factor receptor-like 1 genes in grass carp (Ctenopharyngodon idella).

PubMed

Lin, Si-Tong; Zheng, Guo-Dong; Sun, Yi-Wen; Chen, Jie; Jiang, Xia-Yun; Zou, Shu-Ming

2015-09-01

Fibroblast growth factor receptor-like 1 (FGFRL1) is a novel FGF receptor (FGFR) lacking an intracellular tyrosine kinase domain. FGFRs control the proliferation, differentiation and migration of cells in various tissues. However the functions of FGFRL1 in teleost fish are currently unknown. In this study, we report the identification of two fgfrl1 genes in grass carp (Ctenopharyngodon idella) that share 56% amino acid sequence identity. Both fgfrl1a and 1b were transcribed throughout embryogenesis, and mRNA levels were particularly high during somitogenesis. Using in situ hybridization, fgfrl1a transcripts were detected in notochord, somites, brain and eye at 14, 24 and 36 h post fertilization (hpf). In contrast, fgfrl1b was transcribed mainly in the endoderm at 14 hpf, in the gut and proctodeum at 24 hpf, and in the lens, pharyngeal arch and proctodeum at 36 hpf. In adult fish, fgfrl1a was abundantly expressed in heart, brain and muscle, while fgfrl1b was expressed strongly in eye, muscle and gill. Furthermore, both genes were significantly (p<0.05) up-regulated in muscle and brain during starvation and returned to normal levels rapidly after re-feeding. Exogenous treatment with different doses of human growth hormone down-regulated the expression of both genes in brain and muscle (p<0.05). These results suggest that Fgfrl1a and 1b play divergent roles in regulating growth and development in grass carp. Copyright © 2015 Elsevier Inc. All rights reserved.

Lipidomic profiling of patient-specific iPSC-derived hepatocyte-like cells

PubMed Central

Viiri, Leena E.; Vihervaara, Terhi; Koistinen, Kaisa M.; Hilvo, Mika; Ekroos, Kim; Käkelä, Reijo; Aalto-Setälä, Katriina

2017-01-01

ABSTRACT Hepatocyte-like cells (HLCs) differentiated from human induced pluripotent stem cells (iPSCs) offer an alternative model to primary human hepatocytes to study lipid aberrations. However, the detailed lipid profile of HLCs is yet unknown. In the current study, functional HLCs were differentiated from iPSCs generated from dermal fibroblasts of three individuals by a three-step protocol through the definitive endoderm (DE) stage. In parallel, detailed lipidomic analyses as well as gene expression profiling of a set of lipid-metabolism-related genes were performed during the entire differentiation process from iPSCs to HLCs. Additionally, fatty acid (FA) composition of the cell culture media at different stages was determined. Our results show that major alterations in the molecular species of lipids occurring during DE and early hepatic differentiation stages mainly mirror the quality and quantity of the FAs supplied in culture medium at each stage. Polyunsaturated phospholipids and sphingolipids with a very long FA were produced in the cells at a later stage of differentiation. This work uncovers the previously unknown lipid composition of iPSC-HLCs and its alterations during the differentiation in conjunction with the expression of key lipid-associated genes. Together with biochemical, functional and gene expression measurements, the lipidomic analyses allowed us to improve our understanding of the concerted influence of the exogenous metabolite supply and cellular biosynthesis essential for iPSC-HLC differentiation and function. Importantly, the study describes in detail a cell model that can be applied in exploring, for example, the lipid metabolism involved in the development of fatty liver disease or atherosclerosis. PMID:28733363

Dynamic regulation of EZH2 from HPSc to hepatocyte-like cell fate

PubMed Central

Helsen, Nicky; Vanhove, Jolien; Boon, Ruben; Xu, Zhuofei; Ordovas, Laura; Verfaillie, Catherine M.

2017-01-01

Currently, drug metabolization and toxicity studies rely on the use of primary human hepatocytes and hepatoma cell lines, which both have conceivable limitations. Human pluripotent stem cell (hPSC)—derived hepatocyte-like cells (HLCs) are an alternative and valuable source of hepatocytes that can overcome these limitations. EZH2 (enhancer of zeste homolog 2), a transcriptional repressor of the polycomb repressive complex 2 (PRC2), may play an important role in hepatocyte development, but its role during in vitro hPSC-HLC differentiation has not yet been assessed. We here demonstrate dynamic regulation of EZH2 during hepatic differentiation of hPSC. To enhance EZH2 expression, we inducibly overexpressed EZH2 between d0 and d8, demonstrating a significant improvement in definitive endoderm formation, and improved generation of HLCs. Despite induction of EZH2 overexpression until d8, EZH2 transcript and protein levels decreased from d4 onwards, which might be caused by expression of microRNAs predicted to inhibit EZH2 expression. In conclusion, our studies demonstrate that EZH2 plays a role in endoderm formation and hepatocyte differentiation, but its expression is tightly post-transcriptionally regulated during this process. PMID:29091973

Pancreatic Endoderm-Derived From Diabetic Patient-Specific Induced Pluripotent Stem Cell Generates Glucose-Responsive Insulin-Secreting Cells.

PubMed

Rajaei, Bahareh; Shamsara, Mehdi; Amirabad, Leila Mohammadi; Massumi, Mohammad; Sanati, Mohammad Hossein

2017-10-01

Human-induced pluripotent stem cells (hiPSCs) can potentially serve as an invaluable source for cell replacement therapy and allow the creation of patient- and disease-specific stem cells without the controversial use of embryos and avoids any immunological incompatibility. The generation of insulin-producing pancreatic β-cells from pluripotent stem cells in vitro provides an unprecedented cell source for personal drug discovery and cell transplantation therapy in diabetes. A new five-step protocol was introduced in this study, effectively induced hiPSCs to differentiate into glucose-responsive insulin-producing cells. This process mimics in vivo pancreatic organogenesis by directing cells through stages resembling definitive endoderm, primitive gut-tube endoderm, posterior foregut, pancreatic endoderm, and endocrine precursor. Each stage of differentiation were characterized by stage-specific markers. The produced cells exhibited many properties of functional β-cells, including expression of critical β-cells transcription factors, the potency to secrete C-peptide in response to high levels of glucose and the presence of mature endocrine secretory granules. This high efficient differentiation protocol, established in this study, yielded 79.18% insulin-secreting cells which were responsive to glucose five times higher than the basal level. These hiPSCs-derived glucose-responsive insulin-secreting cells might provide a promising approach for the treatment of type I diabetes mellitus. J. Cell. Physiol. 232: 2616-2625, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Bisphenol A causes malformation of the head region in embryos of Xenopus laevis and decreases the expression of the ESR-1 gene mediated by Notch signaling.

PubMed

Imaoka, Susumu; Mori, Tomohiro; Kinoshita, Tsutomu

2007-02-01

Bisphenol A (BpA) is widely used in industry and dentistry. Its effects on the embryonic development of Xenopus laevis were investigated. Xenopus embryos at stage 10.5 were treated with BpA. Developmental abnormalities were observed at stage 35; malformation of the head region including eyes and scoliosis. The expression of several markers of embryonic development was investigated by reverse transcription-polymerase chain reaction (RT-PCR). The pan-neural marker SOX-2, the neural stem cell marker nrp-1, the mesodermal marker MyoD, and the endodermal marker sox17alpha, were used. Although the expression of marker genes was not changed by treatment with BpA, that of Pax-6, a key regulator of the morphogenesis of the eyes, was decreased by BpA. Pax-6 is a downstream factor of Notch signaling. So, the expression of a typical Notch-dependent factor, ESR-1, was investigated in the presence of BpA. The expression of ESR-1 was efficiently suppressed by BpA. In whole mount in situ hybridization (WISH), Pax-6 was expressed in the central nervous system and eyes. The expression was lost completely on treatment with BpA. The expression of ESR-1 in the central nervous system and eyes also disappeared with BpA treatment. Injection of the intracellular domain of Notch efficiently recovered ESR-1 expression in the presence of BpA although injection of a ligand for notch, Delta, did not. These results suggest that BpA decreased the expression of ESR-1 by disrupting the Notch signal.

AtERF38 (At2g35700), an AP2/ERF family transcription factor gene from Arabidopsis thaliana, is expressed in specific cell types of roots, stems and seeds that undergo suberization.

PubMed

Lasserre, Eric; Jobet, Edouard; Llauro, Christel; Delseny, Michel

2008-12-01

An inverse genetic approach was used to gain insight into the role of AP2/ERF-type transcription factors genes during plant development in Arabidopsis thaliana. Here we show that the expression pattern of AtERF38, which is, among the organs tested, more intensively expressed in mature siliques and floral stems, is closely associated with tissues that undergo secondary cell wall modifications. Firstly, public microarray data sets analysis indicates that AtERF38 is coregulated with several genes involved in secondary wall thickening. Secondly, this was experimentally confirmed in different types of cells expressing a Pro(AtERF38)::GUS fusion: histochemical analysis revealed strong and specific GUS activity in outer integument cells of mature seeds, endodermal cells of the roots in the primary developmental stage and some sclerified cells of mature inflorescence stems. All of these cells are known or shown here to be characterized by a reinforced wall. The latter, which have not been well characterized to date in Arabidopsis and may be suberized, could benefit of the use of AtERF38 as a specific marker. We were not able to detect any phenotype in an insertion line in which ectopic expression of AtERF38 is caused by the insertion of a T-DNA in its promoter. Nevertheless, AtERF28 may be considered as a candidate regulator of secondary wall metabolism in particular cell types that are not reinforced by the typical deposition of lignin and cellulose, but that have at least in common accumulation of suberin-like lipid polyesters in their walls.

Dynamic in vivo binding of transcription factors to cis-regulatory modules of cer and gsc in the stepwise formation of the Spemann–Mangold organizer

PubMed Central

Sudou, Norihiro; Yamamoto, Shinji; Ogino, Hajime; Taira, Masanori

2012-01-01

How multiple developmental cues are integrated on cis-regulatory modules (CRMs) for cell fate decisions remains uncertain. The Spemann–Mangold organizer in Xenopus embryos expresses the transcription factors Lim1/Lhx1, Otx2, Mix1, Siamois (Sia) and VegT. Reporter analyses using sperm nuclear transplantation and DNA injection showed that cerberus (cer) and goosecoid (gsc) are activated by the aforementioned transcription factors through CRMs conserved between X. laevis and X. tropicalis. ChIP-qPCR analysis for the five transcription factors revealed that cer and gsc CRMs are initially bound by both Sia and VegT at the late blastula stage, and subsequently bound by all five factors at the gastrula stage. At the neurula stage, only binding of Lim1 and Otx2 to the gsc CRM, among others, persists, which corresponds to their co-expression in the prechordal plate. Based on these data, together with detailed expression pattern analysis, we propose a new model of stepwise formation of the organizer, in which (1) maternal VegT and Wnt-induced Sia first bind to CRMs at the blastula stage; then (2) Nodal-inducible Lim1, Otx2, Mix1 and zygotic VegT are bound to CRMs in the dorsal endodermal and mesodermal regions where all these genes are co-expressed; and (3) these two regions are combined at the gastrula stage to form the organizer. Thus, the in vivo dynamics of multiple transcription factors highlight their roles in the initiation and maintenance of gene expression, and also reveal the stepwise integration of maternal, Nodal and Wnt signaling on CRMs of organizer genes to generate the organizer. PMID:22492356

Dynamic in vivo binding of transcription factors to cis-regulatory modules of cer and gsc in the stepwise formation of the Spemann-Mangold organizer.

PubMed

Sudou, Norihiro; Yamamoto, Shinji; Ogino, Hajime; Taira, Masanori

2012-05-01

How multiple developmental cues are integrated on cis-regulatory modules (CRMs) for cell fate decisions remains uncertain. The Spemann-Mangold organizer in Xenopus embryos expresses the transcription factors Lim1/Lhx1, Otx2, Mix1, Siamois (Sia) and VegT. Reporter analyses using sperm nuclear transplantation and DNA injection showed that cerberus (cer) and goosecoid (gsc) are activated by the aforementioned transcription factors through CRMs conserved between X. laevis and X. tropicalis. ChIP-qPCR analysis for the five transcription factors revealed that cer and gsc CRMs are initially bound by both Sia and VegT at the late blastula stage, and subsequently bound by all five factors at the gastrula stage. At the neurula stage, only binding of Lim1 and Otx2 to the gsc CRM, among others, persists, which corresponds to their co-expression in the prechordal plate. Based on these data, together with detailed expression pattern analysis, we propose a new model of stepwise formation of the organizer, in which (1) maternal VegT and Wnt-induced Sia first bind to CRMs at the blastula stage; then (2) Nodal-inducible Lim1, Otx2, Mix1 and zygotic VegT are bound to CRMs in the dorsal endodermal and mesodermal regions where all these genes are co-expressed; and (3) these two regions are combined at the gastrula stage to form the organizer. Thus, the in vivo dynamics of multiple transcription factors highlight their roles in the initiation and maintenance of gene expression, and also reveal the stepwise integration of maternal, Nodal and Wnt signaling on CRMs of organizer genes to generate the organizer.

Supratentorial endodermal cysts: review of literature and case report.

PubMed

Caruso, Riccardo; Artico, Marco; Colonnese, Claudio; Marrocco, Luigi; Wierzbicki, Venceslao

2013-11-01

Supratentorial endodermal cysts are very rare pathological entities. Their pathoembryology is largely unknown and they can represent a diagnostic challenge. A research performed on the PubMed database in December 2010, to screen for supratentorial endodermal cyst studies, demonstrated that since 1960 only 31 supratentorial endodermal cysts have been described in the literature, including our case: a 42-year-old woman with a parasellar endodermal cyst. These lesions are usually benign. As with other types of brain cysts, the signs and symptoms caused by supratentorial endodermal cysts are mainly linked to the compression or irritation of surrounding neural structures. Upon neuroimaging examination, they typically appear as a round or lobulated mass. The signal intensity may vary depending on the protein content of the cyst. The majority of reported supratentorial endodermal cysts were completely excised with good or excellent results. Incomplete excision can result in an increased risk of recurrence, infection, and dissemination. Georg Thieme Verlag KG Stuttgart · New York.

Selection of stable reference genes for quantitative rt-PCR comparisons of mouse embryonic and extra-embryonic stem cells.

PubMed

Veazey, Kylee J; Golding, Michael C

2011-01-01

Isolation and culture of both embryonic and tissue specific stem cells provide an enormous opportunity to study the molecular processes driving development. To gain insight into the initial events underpinning mammalian embryogenesis, pluripotent stem cells from each of the three distinct lineages present within the preimplantation blastocyst have been derived. Embryonic (ES), trophectoderm (TS) and extraembryonic endoderm (XEN) stem cells possess the developmental potential of their founding lineages and seemingly utilize distinct epigenetic modalities to program gene expression. However, the basis for these differing cellular identities and epigenetic properties remain poorly defined.Quantitative reverse transcription-polymerase chain reaction (qPCR) is a powerful and efficient means of rapidly comparing patterns of gene expression between different developmental stages and experimental conditions. However, careful, empirical selection of appropriate reference genes is essential to accurately measuring transcriptional differences. Here we report the quantitation and evaluation of fourteen commonly used references genes between ES, TS and XEN stem cells. These included: Actb, B2m, Hsp70, Gapdh, Gusb, H2afz, Hk2, Hprt, Pgk1, Ppia, Rn7sk, Sdha, Tbp and Ywhaz. Utilizing three independent statistical analysis, we identify Pgk1, Sdha and Tbp as the most stable reference genes between each of these stem cell types. Furthermore, we identify Sdha, Tbp and Ywhaz as well as Ywhaz, Pgk1 and Hk2 as the three most stable reference genes through the in vitro differentiation of embryonic and trophectoderm stem cells respectively.Understanding the transcriptional and epigenetic regulatory mechanisms controlling cellular identity within these distinct stem cell types provides essential insight into cellular processes controlling both embryogenesis and stem cell biology. Normalizing quantitative RT-PCR measurements using the geometric mean CT values obtained for the identified mRNAs, offers a reliable method to assess differing patterns of gene expression between the three founding stem cell lineages present within the mammalian preimplantation embryo.

A threshold of GATA4 and GATA6 expression is required for cardiovascular development

PubMed Central

Xin, Mei; Davis, Christopher A.; Molkentin, Jeffery D.; Lien, Ching-Ling; Duncan, Stephen A.; Richardson, James A.; Olson, Eric N.

2006-01-01

The zinc-finger transcription factors GATA4 and GATA6 play critical roles in embryonic development. Mouse embryos lacking GATA4 die at embryonic day (E) 8.5 because of failure of ventral foregut closure and cardiac bifida, whereas GATA6 is essential for development of the visceral endoderm. Although mice that are heterozygous for either a GATA4 or GATA6 null allele are normal, we show that compound heterozygosity of GATA4 and GATA6 results in embryonic lethality by E13.5 accompanied by a spectrum of cardiovascular defects, including thin-walled myocardium, ventricular and aortopulmonary septal defects, and abnormal smooth muscle development. Myocardial hypoplasia in GATA4/GATA6 double heterozygous mutant embryos is associated with reduced proliferation of cardiomyocytes, diminished expression of the myogenic transcription factor MEF2C (myocyte enhancer factor 2C), and down-regulation of β-myosin heavy chain expression, a key determinant of cardiac contractility. These findings reveal a threshold of GATA4 and GATA6 activity that is required for gene expression in the developing cardiovascular system and underscore the potential of recessive mutations to perturb the delicate regulation of cardiovascular development. PMID:16847256

Novel FOXA2 mutation causes Hyperinsulinism, Hypopituitarism with Craniofacial and Endoderm-derived organ abnormalities.

PubMed

Giri, Dinesh; Vignola, Maria Lillina; Gualtieri, Angelica; Scagliotti, Valeria; McNamara, Paul; Peak, Matthew; Didi, Mohammed; Gaston-Massuet, Carles; Senniappan, Senthil

2017-11-15

Congenital hypopituitarism (CH) is characterized by the deficiency of one or more pituitary hormones and can present alone or in association with complex disorders. Congenital hyperinsulinism (CHI) is a disorder of unregulated insulin secretion despite hypoglycaemia that can occur in isolation or as part of a wider syndrome. Molecular diagnosis is unknown in many cases of CH and CHI. The underlying genetic etiology causing the complex phenotype of CH and CHI is unknown. In this study, we identified a de novo heterozygous mutation in the developmental transcription factor, forkhead box A2, FOXA2 (c.505T>C, p.S169P) in a child with CHI and CH with craniofacial dysmorphic features, choroidal coloboma and endoderm-derived organ malformations in liver, lung and gastrointestinal tract by whole exome sequencing. The mutation is at a highly conserved residue within the DNA binding domain. We demonstrated strong expression of Foxa2 mRNA in the developing hypothalamus, pituitary, pancreas, lungs and oesophagus of mouse embryos using in situ hybridization. Expression profiling on human embryos by immunohistochemistry showed strong expression of hFOXA2 in the neural tube, third ventricle, diencephalon and pancreas. Transient transfection of HEK293T cells with Wt (Wild type) hFOXA2 or mutant hFOXA2 showed an impairment in transcriptional reporter activity by the mutant hFOXA2. Further analyses using western blot assays showed that the FOXA2 p.(S169P) variant is pathogenic resulting in lower expression levels when compared with Wt hFOXA2. Our results show, for the first time, the causative role of FOXA2 in a complex congenital syndrome with hypopituitarism, hyperinsulinism and endoderm-derived organ abnormalities. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Femtosecond laser assisted photo-transfection and differentiation of mouse embryonic stem cells

NASA Astrophysics Data System (ADS)

Thobakgale, Lebogang; Manoto, Sello; Ombinda Lemboumba, Satuurnin; Maaza, Malik; Mthunzi-Kufa, Patience

2018-02-01

In tissue engineering research, stem cells have been used as starting material in the synthesis of mammalian cells for the treatment of various cell based diseases. This is done by manipulating the DNA content of the cells to induce a specific effect such as increased proliferation or developing a new cell type through the process of differentiation. Such controlled gene expression of stem cells is achieved by the method of transfection, where exogenous plasmid deoxyribonucleic acid (pDNA) is inserted into a stem cell using chemical, viral or physical methods. In this research, we used femtosecond (fs) laser pulses from a home-build microscope system to perforate the cellular membrane and allow entry of selected pDNA to alter the behaviour of mouse embryonic stem cells (mESCs). In one set of experiments, we induce fluorescence on mESCs using green fluorescence protein plasmid (pGFP) while in other tests; differentiation of mESCs into endoderm cells is performed using Sox-17 plasmid DNA (pSox-17). Primitive endoderm formation was thereafter confirmed using polymerase chain reactions (PCR) and the Sox-17 primer. Cell viability studies using adenosine triphosphate were also conducted. From the data, it was concluded that the photo-transfection method is biocompatible since it was able to induce fluorescence in mESCs. Secondly, it was confirmed that Sox-17 was photo-transfected successfully using 6 μW laser power, 128 fs pulses and 1kHz pulse repetition rate.

Three Arabidopsis Fatty Acyl-Coenzyme A Reductases, FAR1, FAR4, and FAR5, Generate Primary Fatty Alcohols Associated with Suberin Deposition1[C][W][OA

PubMed Central

Domergue, Frédéric; Vishwanath, Sollapura J.; Joubès, Jérôme; Ono, Jasmine; Lee, Jennifer A.; Bourdon, Matthieu; Alhattab, Reem; Lowe, Christine; Pascal, Stéphanie; Lessire, René; Rowland, Owen

2010-01-01

Suberin is a protective hydrophobic barrier consisting of phenolics, glycerol, and a variety of fatty acid derivatives, including C18:0-C22:0 primary fatty alcohols. An eight-member gene family encoding alcohol-forming fatty acyl-coenzyme A reductases (FARs) has been identified in Arabidopsis (Arabidopsis thaliana). Promoter-driven expression of the β-glucuronidase reporter gene indicated that three of these genes, FAR1(At5g22500), FAR4(At3g44540), and FAR5(At3g44550), are expressed in root endodermal cells. The three genes were transcriptionally induced by wounding and salt stress. These patterns of gene expression coincide with known sites of suberin deposition. We then characterized a set of mutants with T-DNA insertions in FAR1, FAR4, or FAR5 and found that the suberin compositions of roots and seed coats were modified in each far mutant. Specifically, C18:0-OH was reduced in far5-1, C20:0-OH was reduced in far4-1, and C22:0-OH was reduced in far1-1. We also analyzed the composition of polymer-bound lipids of leaves before and after wounding and found that the basal levels of C18:0-C22:0 primary alcohols in wild-type leaves were increased by wounding. In contrast, C18:0-OH and C22:0-OH were not increased by wounding in far5-1 and far1-1 mutants, respectively. Heterologous expression of FAR1, FAR4, and FAR5 in yeast confirmed that they are indeed active alcohol-forming FARs with distinct, but overlapping, chain length specificities ranging from C18:0 to C24:0. Altogether, these results indicate that Arabidopsis FAR1, FAR4, and FAR5 generate the fatty alcohols found in root, seed coat, and wound-induced leaf tissue. PMID:20571114

Toddler signaling regulates mesodermal cell migration downstream of Nodal signaling

PubMed Central

Norris, Megan L; Pauli, Andrea; Gagnon, James A; Lord, Nathan D; Rogers, Katherine W; Mosimann, Christian; Zon, Leonard I

2017-01-01

Toddler/Apela/Elabela is a conserved secreted peptide that regulates mesendoderm development during zebrafish gastrulation. Two non-exclusive models have been proposed to explain Toddler function. The ‘specification model’ postulates that Toddler signaling enhances Nodal signaling to properly specify endoderm, whereas the ‘migration model’ posits that Toddler signaling regulates mesendodermal cell migration downstream of Nodal signaling. Here, we test key predictions of both models. We find that in toddler mutants Nodal signaling is initially normal and increasing endoderm specification does not rescue mesendodermal cell migration. Mesodermal cell migration defects in toddler mutants result from a decrease in animal pole-directed migration and are independent of endoderm. Conversely, endodermal cell migration defects are dependent on a Cxcr4a-regulated tether of the endoderm to mesoderm. These results suggest that Toddler signaling regulates mesodermal cell migration downstream of Nodal signaling and indirectly affects endodermal cell migration via Cxcr4a-signaling. PMID:29117894

The mevalonate pathway regulates primitive streak formation via protein farnesylation

PubMed Central

Okamoto-Uchida, Yoshimi; Yu, Ruoxing; Miyamura, Norio; Arima, Norie; Ishigami-Yuasa, Mari; Kagechika, Hiroyuki; Yoshida, Suguru; Hosoya, Takamitsu; Nawa, Makiko; Kasama, Takeshi; Asaoka, Yoichi; Alois, Reiner Wimmer; Elling, Ulrich; Penninger, Josef M.; Nishina, Sachiko; Azuma, Noriyuki; Nishina, Hiroshi

2016-01-01

The primitive streak in peri-implantation embryos forms the mesoderm and endoderm and controls cell differentiation. The metabolic cues regulating primitive streak formation remain largely unknown. Here we utilised a mouse embryonic stem (ES) cell differentiation system and a library of well-characterised drugs to identify these metabolic factors. We found that statins, which inhibit the mevalonate metabolic pathway, suppressed primitive streak formation in vitro and in vivo. Using metabolomics and pharmacologic approaches we identified the downstream signalling pathway of mevalonate and revealed that primitive streak formation requires protein farnesylation but not cholesterol synthesis. A tagging-via-substrate approach revealed that nuclear lamin B1 and small G proteins were farnesylated in embryoid bodies and important for primitive streak gene expression. In conclusion, protein farnesylation driven by the mevalonate pathway is a metabolic cue essential for primitive streak formation. PMID:27883036

A strategy to discover new organizers identifies a putative heart organizer

PubMed Central

Anderson, Claire; Khan, Mohsin A. F.; Wong, Frances; Solovieva, Tatiana; Oliveira, Nidia M. M.; Baldock, Richard A.; Tickle, Cheryll; Burt, Dave W.; Stern, Claudio D.

2016-01-01

Organizers are regions of the embryo that can both induce new fates and impart pattern on other regions. So far, surprisingly few organizers have been discovered, considering the number of patterned tissue types generated during development. This may be because their discovery has relied on transplantation and ablation experiments. Here we describe a new approach, using chick embryos, to discover organizers based on a common gene expression signature, and use it to uncover the anterior intestinal portal (AIP) endoderm as a putative heart organizer. We show that the AIP can induce cardiac identity from non-cardiac mesoderm and that it can pattern this by specifying ventricular and suppressing atrial regional identity. We also uncover some of the signals responsible. The method holds promise as a tool to discover other novel organizers acting during development. PMID:27557800

A Fate Map of the Murine Pancreas Buds Reveals a Multipotent Ventral Foregut Organ Progenitor

PubMed Central

Angelo, Jesse R.; Guerrero-Zayas, Mara-Isel; Tremblay, Kimberly D.

2012-01-01

The definitive endoderm is the embryonic germ layer that gives rise to the budding endodermal organs including the thyroid, lung, liver and pancreas as well as the remainder of the gut tube. DiI fate mapping and whole embryo culture were used to determine the endodermal origin of the 9.5 days post coitum (dpc) dorsal and ventral pancreas buds. Our results demonstrate that the progenitors of each bud occupy distinct endodermal territories. Dorsal bud progenitors are located in the medial endoderm overlying somites 2–4 between the 2 and 11 somite stage (SS). The endoderm forming the ventral pancreas bud is found in 2 distinct regions. One territory originates from the left and right lateral endoderm caudal to the anterior intestinal portal by the 6 SS and the second domain is derived from the ventral midline of the endoderm lip (VMEL). Unlike the laterally located ventral foregut progenitors, the VMEL population harbors a multipotent progenitor that contributes to the thyroid bud, the rostral cap of the liver bud, ventral midline of the liver bud and the midline of the ventral pancreas bud in a temporally restricted manner. This data suggests that the midline of the 9.5 dpc thyroid, liver and ventral pancreas buds originates from the same progenitor population, demonstrating a developmental link between all three ventral foregut buds. Taken together, these data define the location of the dorsal and ventral pancreas progenitors in the prespecified endodermal sheet and should lead to insights into the inductive events required for pancreas specification. PMID:22815796

Isolation of New Gravitropic Mutants under Hypergravity Conditions.

PubMed

Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

2016-01-01

Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

Isolation of New Gravitropic Mutants under Hypergravity Conditions

PubMed Central

Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T.

2016-01-01

Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 (eal1) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis. PMID:27746791

Roles of Soybean Plasma Membrane Intrinsic Protein GmPIP2;9 in Drought Tolerance and Seed Development.

PubMed

Lu, Linghong; Dong, Changhe; Liu, Ruifang; Zhou, Bin; Wang, Chuang; Shou, Huixia

2018-01-01

Aquaporins play an essential role in water uptake and transport in vascular plants. The soybean genome contains a total of 22 plasma membrane intrinsic protein (PIP) genes. To identify candidate PIPs important for soybean yield and stress tolerance, we studied the transcript levels of all 22 soybean PIPs. We found that a GmPIP2 subfamily member, GmPIP2;9, was predominately expressed in roots and developing seeds. Here, we show that GmPIP2;9 localized to the plasma membrane and had high water channel activity when expressed in Xenopus oocytes. Using transgenic soybean plants expressing a native GmPIP2;9 promoter driving a GUS-reporter gene, it was found high GUS expression in the roots, in particular, in the endoderm, pericycle, and vascular tissues of the roots of transgenic plants. In addition, GmPIP2;9 was also highly expressed in developing pods. GmPIP2;9 expression significantly increased in short term of polyethylene glycol (PEG)-mediated drought stress treatment. GmPIP2;9 overexpression increased tolerance to drought stress in both solution cultures and soil plots. Drought stress in combination with GmPIP2;9 overexpression increased net CO 2 assimilation of photosynthesis, stomata conductance, and transpiration rate, suggesting that GmPIP2;9- overexpressing transgenic plants were less stressed than wild-type (WT) plants. Furthermore, field experiments showed that GmPIP2;9 -overexpressing plants had significantly more pod numbers and larger seed sizes than WT plants. In summary, the study demonstrated that GmPIP2;9 has water transport activity. Its relative high expression levels in roots and developing pods are in agreement with the phenotypes of GmPIP2;9 -overexpressing plants in drought stress tolerance and seed development.

Roles of Soybean Plasma Membrane Intrinsic Protein GmPIP2;9 in Drought Tolerance and Seed Development

PubMed Central

Lu, Linghong; Dong, Changhe; Liu, Ruifang; Zhou, Bin; Wang, Chuang; Shou, Huixia

2018-01-01

Aquaporins play an essential role in water uptake and transport in vascular plants. The soybean genome contains a total of 22 plasma membrane intrinsic protein (PIP) genes. To identify candidate PIPs important for soybean yield and stress tolerance, we studied the transcript levels of all 22 soybean PIPs. We found that a GmPIP2 subfamily member, GmPIP2;9, was predominately expressed in roots and developing seeds. Here, we show that GmPIP2;9 localized to the plasma membrane and had high water channel activity when expressed in Xenopus oocytes. Using transgenic soybean plants expressing a native GmPIP2;9 promoter driving a GUS-reporter gene, it was found high GUS expression in the roots, in particular, in the endoderm, pericycle, and vascular tissues of the roots of transgenic plants. In addition, GmPIP2;9 was also highly expressed in developing pods. GmPIP2;9 expression significantly increased in short term of polyethylene glycol (PEG)-mediated drought stress treatment. GmPIP2;9 overexpression increased tolerance to drought stress in both solution cultures and soil plots. Drought stress in combination with GmPIP2;9 overexpression increased net CO2 assimilation of photosynthesis, stomata conductance, and transpiration rate, suggesting that GmPIP2;9-overexpressing transgenic plants were less stressed than wild-type (WT) plants. Furthermore, field experiments showed that GmPIP2;9-overexpressing plants had significantly more pod numbers and larger seed sizes than WT plants. In summary, the study demonstrated that GmPIP2;9 has water transport activity. Its relative high expression levels in roots and developing pods are in agreement with the phenotypes of GmPIP2;9-overexpressing plants in drought stress tolerance and seed development. PMID:29755491

Use of a fluorescent membrane probe to identify zooxanthellae in hospite among dissociated endoderm cell culture from coral.

PubMed

Chen, C-S; Lin, H-P; Yeh, C-C; Fang, L-S

2005-12-01

Preparation of homogeneous endoderm cells and culture is a prerequisite to understanding the cellular and molecular mechanism of endosymbiosis in the cnidarian-dinoflagellate association. During the cell isolation from the stony coral Euphyllia glabrescens, various amounts of symbiotic endoderm cells were found to release their symbionts (Symbiodinium spp., or zooxanthellae in generic usage) into the culture. Due to the bulky occupation by zooxanthellae inside the endoderm cell, the symbiotic endoderm cells, or zooxanthellae in hospite, are difficult to be distinguished from released zooxanthellae by microscopic examination. We now report a method for this identification using a fluorescent analogue of sphingomyelin, N-[5-(5,7-dimethyl boron dipyrromethene difluoride)-1-pentanoyl]-D-erythro-sphingosylphosphorylcholine (C(5)-DMB-SM). Incubation of symbiotic endoderm cells with C(5)-DMB-SM-defatted bovine serum albumin (DF-BSA) complex results in bright fluorescent membrane staining. Nevertheless, the membrane staining of free-living or released zooxanthellae by this complex is significantly decreased or even diminished. This method has provided a fast and reliable assay to identify symbiotic endoderm cells and will greatly accelerate the progress of endosymbiosis research.

Foxi2 Is an Animally Localized Maternal mRNA in Xenopus, and an Activator of the Zygotic Ectoderm Activator Foxi1e

PubMed Central

Cha, Sang-Wook; McAdams, Meredith; Kormish, Jay; Wylie, Christopher; Kofron, Matthew

2012-01-01

Foxi1e is a zygotic transcription factor that is essential for the expression of early ectodermal genes. It is expressed in a highly specific pattern, only in the deep cell layers of the animal hemisphere, and in a mosaic pattern in which expressing cells are interspersed with non-expressing cells. Previous work has shown that several signals in the blastula control this expression pattern, including nodals, the TGFβ family member Vg1, and Notch. However, these are all inhibitory, which raises the question of what activates Foxi1e. In this work, we show that a related Forkhead family protein, Foxi2, is a maternal activator of Foxi1e. Foxi2 mRNA is maternally encoded, and highly enriched in animal hemisphere cells of the blastula. ChIP assays show that it acts directly on upstream regulatory elements of Foxi1e. Its effect is specific, since animal cells depleted of Foxi2 are able to respond normally to mesoderm inducing signals from vegetal cells. Foxi2 thus acts as a link between the oocyte and the early pathway to ectoderm, in a similar fashion to the vegetally localized VegT acts to initiate endoderm and mesoderm formation. PMID:22848601

Wnt signaling maintains the notochord fate for progenitor cells and supports the posterior extension of the notochord.

PubMed

Ukita, Kanako; Hirahara, Shino; Oshima, Naoko; Imuta, Yu; Yoshimoto, Aki; Jang, Chuan-Wei; Oginuma, Masayuki; Saga, Yumiko; Behringer, Richard R; Kondoh, Hisato; Sasaki, Hiroshi

2009-10-01

The notochord develops from notochord progenitor cells (NPCs) and functions as a major signaling center to regulate trunk and tail development. NPCs are initially specified in the node by Wnt and Nodal signals at the gastrula stage. However, the underlying mechanism that maintains the NPCs throughout embryogenesis to contribute to the posterior extension of the notochord remains unclear. Here, we demonstrate that Wnt signaling in the NPCs is essential for posterior extension of the notochord. Genetic labeling revealed that the Noto-expressing cells in the ventral node contribute the NPCs that reside in the tail bud. Robust Wnt signaling in the NPCs was observed during posterior notochord extension. Genetic attenuation of the Wnt signal via notochord-specific beta-catenin gene ablation resulted in posterior truncation of the notochord. In the NPCs of such mutant embryos, the expression of notochord-specific genes was down-regulated, and an endodermal marker, E-cadherin, was observed. No significant alteration of cell proliferation or apoptosis of the NPCs was detected. Taken together, our data indicate that the NPCs are derived from Noto-positive node cells, and are not fully committed to a notochordal fate. Sustained Wnt signaling is required to maintain the NPCs' notochordal fate.

The effect of adriamycin exposure on the notochord of mouse embryos.

PubMed

Hajduk, Piotr; May, Alison; Puri, Prem; Murphy, Paula

2012-04-01

The notochord has important structural and signaling properties during vertebrate development with key roles in patterning surrounding tissues, including the foregut. The adriamycin mouse model is an established model of foregut anomalies where exposure of embryos in utero to the drug adriamycin leads to malformations including oesophageal atresia and tracheoesophageal fistula. In addition to foregut abnormalities, treatment also causes branching, displacement, and hypertrophy of the notochord. Here, we explore the hypothesis that the notochord may be a primary target of disruption leading to abnormal patterning of the foregut by examining notochord position and structure in early embryos following adriamycin exposure. Treated (n = 46) and control (n = 30) embryos were examined during the crucial period when the notochord normally delaminates away from the foregut endoderm (6-28 somite pairs). Transverse sections were derived from the anterior foregut and analyzed by confocal microscopy following immunodetection of extracellular matrix markers E-cadherin and Laminin. In adriamycin-treated embryos across all stages, the notochord was abnormally displaced ventrally with prolonged attachment to the foregut endoderm. While E-cadherin was normally detected in the foregut endoderm with no expression in the notochord of control embryos, treated embryos up to 24 somites showed ectopic notochordal expression indicating a change in characteristics of the tissue; specifically an increase in intracellular adhesiveness, which may be instrumental in structural changes, affecting mechanical and signaling properties. This is consistent with disruption of the notochord leading to altered signaling to the foregut causing abnormal patterning and congenital foregut malformations. © 2012 Wiley Periodicals, Inc.

FGF7 and cell density are required for final differentiation of pancreatic amylase-positive cells from human ES cells.

PubMed

Takizawa-Shirasawa, Sakiko; Yoshie, Susumu; Yue, Fengming; Mogi, Akimi; Yokoyama, Tadayuki; Tomotsune, Daihachiro; Sasaki, Katsunori

2013-12-01

The major molecular signals of pancreatic exocrine development are largely unknown. We examine the role of fibroblast growth factor 7 (FGF7) in the final induction of pancreatic amylase-containing exocrine cells from induced-pancreatic progenitor cells derived from human embryonic stem (hES) cells. Our protocol consisted in three steps: Step I, differentiation of definitive endoderm (DE) by activin A treatment of hES cell colonies; Step II, differentiation of pancreatic progenitor cells by re-plating of the cells of Step I onto 24-well plates at high density and stimulation with all-trans retinoic acid; Step III, differentiation of pancreatic exocrine cells with a combination of FGF7, glucagon-like peptide 1 and nicotinamide. The expression levels of pancreatic endodermal markers such as Foxa2, Sox17 and gut tube endoderm marker HNF1β were up-regulated in both Step I and II. Moreover, in Step III, the induced cells expressed pancreatic markers such as amylase, carboxypeptidase A and chymotrypsinogen B, which were similar to those in normal human pancreas. From day 8 in Step III, cells immunohistochemically positive for amylase and for carboxypeptidase A, a pancreatic exocrine cell product, were induced by FGF7. Pancreatic progenitor Pdx1-positive cells were localized in proximity to the amylase-positive cells. In the absence of FGF7, few amylase-positive cells were identified. Thus, our three-step culture protocol for human ES cells effectively induces the differentiation of amylase- and carboxypeptidase-A-containing pancreatic exocrine cells.

The lining of the gut in the developing rat embryo. Its relation to the hypoblast (primary endoderm) and the notochord.

PubMed

Lamers, W H; Spliet, W G; Langemeyer, R A

1987-01-01

A light microscopical study of the morphogenesis of the gut in the rat embryo was undertaken to provide a careful map of temporal changes in the topographical relations of the (definitive) endoderm, the notochord and the hypoblast (primary endoderm). The borderline between the (definitive) endoderm and the hypoblast that appears upon gastrulation defines the lateral extension of the future gut epithelium. Within this initially semiglobular disk, the foregut and hindgut originate sequentially as blind, rapidly growing pouches. Upon the turning of the embryo, the hardly growing peripheral part of the disk becomes located in the vitelline duct. Within the head process, endodermal and notochordal cells could not be separately identified. However, slightly more posteriorly notochordal cells are seen to become embedded into the endoderm of the foregut during gastrulation. This process is not seen over the hindgut and may explain why the detachment of the notochord from the (fore)gut begins caudally.

Cdx1 and cdx2 expression during intestinal development.

PubMed

Silberg, D G; Swain, G P; Suh, E R; Traber, P G

2000-10-01

The intestine-specific transcription factors Cdx1 and Cdx2 are candidate genes for directing intestinal development, differentiation, and maintenance of the intestinal phenotype. This study focused on the complex patterns of expression of Cdx1 and Cdx2 during mouse gastrointestinal development. Embryonic and postnatal mouse tissues were analyzed by immunohistochemistry to determine protein expression of Cdx1 and Cdx2 in the developing intestinal tract. Cdx2 protein expression was observed at 9. 5 postcoitum (pc), whereas weak expression of Cdx1 protein was first seen at 12.5 pc in the distal developing intestine (hindgut). Expression of Cdx1 increased from 13.5 to 14.5 pc during the endoderm/epithelial transition with predominately distal expression. In contrast to Cdx1, there was intense expression of Cdx2 in all but the distal portions of the developing intestine. Cdx2 expression remained low in the distal colon throughout postnatal development. A gradient of expression formed in the crypt-villus axis, with Cdx1 primarily in the crypt and Cdx2 primarily in the villus. Direct comparison of the patterns of Cdx1 and Cdx2 protein expression during development as performed in this study provides new insights into their potential functional roles. The relative expression of Cdx1 to Cdx2 protein may be important in the anterior to posterior patterning of the intestinal epithelium and in defining patterns of proliferation and differentiation along the crypt-villus axis.

Subtype-specific differentiation of cardiac pacemaker cell clusters from human induced pluripotent stem cells.

PubMed

Schweizer, Patrick A; Darche, Fabrice F; Ullrich, Nina D; Geschwill, Pascal; Greber, Boris; Rivinius, Rasmus; Seyler, Claudia; Müller-Decker, Karin; Draguhn, Andreas; Utikal, Jochen; Koenen, Michael; Katus, Hugo A; Thomas, Dierk

2017-10-16

Human induced pluripotent stem cells (hiPSC) harbor the potential to differentiate into diverse cardiac cell types. Previous experimental efforts were primarily directed at the generation of hiPSC-derived cells with ventricular cardiomyocyte characteristics. Aiming at a straightforward approach for pacemaker cell modeling and replacement, we sought to selectively differentiate cells with nodal-type properties. hiPSC were differentiated into spontaneously beating clusters by co-culturing with visceral endoderm-like cells in a serum-free medium. Subsequent culturing in a specified fetal bovine serum (FBS)-enriched cell medium produced a pacemaker-type phenotype that was studied in detail using quantitative real-time polymerase chain reaction (qRT-PCR), immunocytochemistry, and patch-clamp electrophysiology. Further investigations comprised pharmacological stimulations and co-culturing with neonatal cardiomyocytes. hiPSC co-cultured in a serum-free medium with the visceral endoderm-like cell line END-2 produced spontaneously beating clusters after 10-12 days of culture. The pacemaker-specific genes HCN4, TBX3, and TBX18 were abundantly expressed at this early developmental stage, while levels of sarcomeric gene products remained low. We observed that working-type cardiomyogenic differentiation can be suppressed by transfer of early clusters into a FBS-enriched cell medium immediately after beating onset. After 6 weeks under these conditions, sinoatrial node (SAN) hallmark genes remained at high levels, while working-type myocardial transcripts (NKX2.5, TBX5) were low. Clusters were characterized by regular activity and robust beating rates (70-90 beats/min) and were triggered by spontaneous Ca 2+ transients recapitulating calcium clock properties of genuine pacemaker cells. They were responsive to adrenergic/cholinergic stimulation and able to pace neonatal rat ventricular myocytes in co-culture experiments. Action potential (AP) measurements of cells individualized from clusters exhibited nodal-type (63.4%) and atrial-type (36.6%) AP morphologies, while ventricular AP configurations were not observed. We provide a novel culture media-based, transgene-free approach for targeted generation of hiPSC-derived pacemaker-type cells that grow in clusters and offer the potential for disease modeling, drug testing, and individualized cell-based replacement therapy of the SAN.

Murine craniofacial development requires Hdac3-mediated repression of Msx gene expression

PubMed Central

Singh, Nikhil; Gupta, Mudit; Trivedi, Chinmay M.; Singh, Manvendra K.; Li, Li; Epstein, Jonathan A.

2013-01-01

Craniofacial development is characterized by reciprocal interactions between neural crest cells and neighboring cell populations of ectodermal, endodermal and mesodermal origin. Various genetic pathways play critical roles in coordinating the development of cranial structures by modulating the growth, survival and differentiation of neural crest cells. However, the regulation of these pathways, particularly at the epigenomic level, remains poorly understood. Using murine genetics, we show that neural crest cells exhibit a requirement for the class I histone deacetylase Hdac3 during craniofacial development. Mice in which Hdac3 has been conditionally deleted in neural crest demonstrate fully penetrant craniofacial abnormalities, including microcephaly, cleft secondary palate and dental hypoplasia. Consistent with these abnormalities, we observe dysregulation of cell cycle genes and increased apoptosis in neural crest structures in mutant embryos. Known regulators of cell cycle progression and apoptosis in neural crest, including Msx1, Msx2 and Bmp4, are upregulated in Hdac3-deficient cranial mesenchyme. These results suggest that Hdac3 serves as a critical regulator of craniofacial morphogenesis, in part by repressing core apoptotic pathways in cranial neural crest cells. PMID:23506836

The fibronectin leucine-rich repeat transmembrane protein Flrt2 is required in the epicardium to promote heart morphogenesis

PubMed Central

Müller, Pari-Sima; Schulz, Ramona; Maretto, Silvia; Costello, Ita; Srinivas, Shankar; Bikoff, Elizabeth; Robertson, Elizabeth

2011-01-01

The epicardium, the outermost tissue layer that envelops the developing heart and provides essential trophic signals for the myocardium, derives from the pro-epicardial organ (PEO). Two of the three members of the Flrt family of transmembrane glycoproteins, Flrt2 and Flrt3, are strongly co-expressed in the PEO. However, beginning at around day 10 of mouse development, following attachment and outgrowth, Flrt3 is selectively downregulated, and only Flrt2 is exclusively expressed in the fully delaminated epicardium. The present gene-targeting experiments demonstrate that mouse embryos lacking Flrt2 expression arrest at mid-gestation owing to cardiac insufficiency. The defects in integrity of the epicardial sheet and disturbed organization of the underlying basement membrane closely resemble those described in Flrt3-deficient embryos that fail to maintain cell-cell contacts in the anterior visceral endoderm (AVE) signalling centre that normally establishes the A-P axis. Using in vitro and in vivo reconstitution assays, we demonstrate that Flrt2 and Flrt3 are functionally interchangeable. When acting alone, either of these proteins is sufficient to rescue functional activities in the AVE and the developing epicardium. PMID:21350012

Comprehensive single cell-resolution analysis of the role of chromatin regulators in early C. elegans embryogenesis.

PubMed

Krüger, Angela V; Jelier, Rob; Dzyubachyk, Oleh; Zimmerman, Timo; Meijering, Erik; Lehner, Ben

2015-02-15

Chromatin regulators are widely expressed proteins with diverse roles in gene expression, nuclear organization, cell cycle regulation, pluripotency, physiology and development, and are frequently mutated in human diseases such as cancer. Their inhibition often results in pleiotropic effects that are difficult to study using conventional approaches. We have developed a semi-automated nuclear tracking algorithm to quantify the divisions, movements and positions of all nuclei during the early development of Caenorhabditis elegans and have used it to systematically study the effects of inhibiting chromatin regulators. The resulting high dimensional datasets revealed that inhibition of multiple regulators, including F55A3.3 (encoding FACT subunit SUPT16H), lin-53 (RBBP4/7), rba-1 (RBBP4/7), set-16 (MLL2/3), hda-1 (HDAC1/2), swsn-7 (ARID2), and let-526 (ARID1A/1B) affected cell cycle progression and caused chromosome segregation defects. In contrast, inhibition of cir-1 (CIR1) accelerated cell division timing in specific cells of the AB lineage. The inhibition of RNA polymerase II also accelerated these division timings, suggesting that normal gene expression is required to delay cell cycle progression in multiple lineages in the early embryo. Quantitative analyses of the dataset suggested the existence of at least two functionally distinct SWI/SNF chromatin remodeling complex activities in the early embryo, and identified a redundant requirement for the egl-27 and lin-40 MTA orthologs in the development of endoderm and mesoderm lineages. Moreover, our dataset also revealed a characteristic rearrangement of chromatin to the nuclear periphery upon the inhibition of multiple general regulators of gene expression. Our systematic, comprehensive and quantitative datasets illustrate the power of single cell-resolution quantitative tracking and high dimensional phenotyping to investigate gene function. Furthermore, the results provide an overview of the functions of essential chromatin regulators during the early development of an animal. Copyright © 2014 Elsevier Inc. All rights reserved.

A Novel Gene Controlling the Timing of Courtship Initiation in Drosophila melanogaster

PubMed Central

Luu, Peter; Zaki, Sadaf A.; Tran, David H.; French, Rachael L.

2016-01-01

Over the past 35 years, developmental geneticists have made impressive progress toward an understanding of how genes specify morphology and function, particularly as they relate to the specification of each physical component of an organism. In the last 20 years, male courtship behavior in Drosophila melanogaster has emerged as a robust model system for the study of genetic specification of behavior. Courtship behavior is both complex and innate, and a single gene, fruitless (fru), is both necessary and sufficient for all aspects of the courtship ritual. Typically, loss of male-specific Fruitless protein function results in male flies that perform the courtship ritual incorrectly, slowly, or not at all. Here we describe a novel requirement for fru: we have identified a group of cells in which male Fru proteins are required to reduce the speed of courtship initiation. In addition, we have identified a gene, Trapped in endoderm 1 (Tre1), which is required in these cells for normal courtship and mating behavior. Tre1 encodes a G-protein-coupled receptor required for establishment of cell polarity and cell migration and has previously not been shown to be involved in courtship behavior. We describe the results of feminization of the Tre1-expressing neurons, as well as the effects on courtship behavior of mutation of Tre1. In addition, we show that Tre1 is expressed in a sexually dimorphic pattern in the central and peripheral nervous systems and investigate the role of the Tre1 cells in mate identification. PMID:26721856

Early In Vitro Differentiation of Mouse Definitive Endoderm Is Not Correlated with Progressive Maturation of Nuclear DNA Methylation Patterns

PubMed Central

Tajbakhsh, Jian; Gertych, Arkadiusz; Fagg, W. Samuel; Hatada, Seigo; Fair, Jeffrey H.

2011-01-01

The genome organization in pluripotent cells undergoing the first steps of differentiation is highly relevant to the reprogramming process in differentiation. Considering this fact, chromatin texture patterns that identify cells at the very early stage of lineage commitment could serve as valuable tools in the selection of optimal cell phenotypes for regenerative medicine applications. Here we report on the first-time use of high-resolution three-dimensional fluorescence imaging and comprehensive topological cell-by-cell analyses with a novel image-cytometrical approach towards the identification of in situ global nuclear DNA methylation patterns in early endodermal differentiation of mouse ES cells (up to day 6), and the correlations of these patterns with a set of putative markers for pluripotency and endodermal commitment, and the epithelial and mesenchymal character of cells. Utilizing this in vitro cell system as a model for assessing the relationship between differentiation and nuclear DNA methylation patterns, we found that differentiating cell populations display an increasing number of cells with a gain in DNA methylation load: first within their euchromatin, then extending into heterochromatic areas of the nucleus, which also results in significant changes of methylcytosine/global DNA codistribution patterns. We were also able to co-visualize and quantify the concomitant stochastic marker expression on a per-cell basis, for which we did not measure any correlation to methylcytosine loads or distribution patterns. We observe that the progression of global DNA methylation is not correlated with the standard transcription factors associated with endodermal development. Further studies are needed to determine whether the progression of global methylation could represent a useful signature of cellular differentiation. This concept of tracking epigenetic progression may prove useful in the selection of cell phenotypes for future regenerative medicine applications. PMID:21779341

A sequential EMT-MET mechanism drives the differentiation of human embryonic stem cells towards hepatocytes.

PubMed

Li, Qiuhong; Hutchins, Andrew P; Chen, Yong; Li, Shengbiao; Shan, Yongli; Liao, Baojian; Zheng, Dejin; Shi, Xi; Li, Yinxiong; Chan, Wai-Yee; Pan, Guangjin; Wei, Shicheng; Shu, Xiaodong; Pei, Duanqing

2017-05-03

Reprogramming has been shown to involve EMT-MET; however, its role in cell differentiation is unclear. We report here that in vitro differentiation of hESCs to hepatic lineage undergoes a sequential EMT-MET with an obligatory intermediate mesenchymal phase. Gene expression analysis reveals that Activin A-induced formation of definitive endoderm (DE) accompanies a synchronous EMT mediated by autocrine TGFβ signalling followed by a MET process. Pharmacological inhibition of TGFβ signalling blocks the EMT as well as DE formation. We then identify SNAI1 as the key EMT transcriptional factor required for the specification of DE. Genetic ablation of SNAI1 in hESCs does not affect the maintenance of pluripotency or neural differentiation, but completely disrupts the formation of DE. These results reveal a critical mesenchymal phase during the acquisition of DE, highlighting a role for sequential EMT-METs in both differentiation and reprogramming.

Positional cloning identifies zebrafish one-eyed pinhead as a permissive EGF-related ligand required during gastrulation.

PubMed

Zhang, J; Talbot, W S; Schier, A F

1998-01-23

The zebrafish one-eyed pinhead (oep) mutation disrupts embryonic development, resulting in cyclopia and defects in endoderm, prechordal plate, and ventral neuroectoderm formation. We report the molecular isolation of oep using a positional cloning approach. The oep gene encodes a novel EGF-related protein with similarity to the EGF-CFC proteins cripto, cryptic, and FRL-1. Wild-type oep protein contains a functional signal sequence and is membrane-associated. Following ubiquitous maternal and zygotic expression, highest levels of oep mRNA are found in the gastrula margin and in axial structures and forebrain. Widespread misexpression of both membrane-attached and secreted forms of oep rescues prechordal plate and forebrain development in mutant embryos but does not lead to the ectopic induction of these cell types in wild-type fish. These results establish an essential but permissive role for an EGF-related ligand during vertebrate gastrulation.

AMPK governs lineage specification through Tfeb-dependent regulation of lysosomes.

PubMed

Young, Nathan P; Kamireddy, Anwesh; Van Nostrand, Jeanine L; Eichner, Lillian J; Shokhirev, Maxim Nikolaievich; Dayn, Yelena; Shaw, Reuben J

2016-03-01

Faithful execution of developmental programs relies on the acquisition of unique cell identities from pluripotent progenitors, a process governed by combinatorial inputs from numerous signaling cascades that ultimately dictate lineage-specific transcriptional outputs. Despite growing evidence that metabolism is integrated with many molecular networks, how pathways that control energy homeostasis may affect cell fate decisions is largely unknown. Here, we show that AMP-activated protein kinase (AMPK), a central metabolic regulator, plays critical roles in lineage specification. Although AMPK-deficient embryonic stem cells (ESCs) were normal in the pluripotent state, these cells displayed profound defects upon differentiation, failing to generate chimeric embryos and preferentially adopting an ectodermal fate at the expense of the endoderm during embryoid body (EB) formation. AMPK(-/-) EBs exhibited reduced levels of Tfeb, a master transcriptional regulator of lysosomes, leading to diminished endolysosomal function. Remarkably, genetic loss of Tfeb also yielded endodermal defects, while AMPK-null ESCs overexpressing this transcription factor normalized their differential potential, revealing an intimate connection between Tfeb/lysosomes and germ layer specification. The compromised endolysosomal system resulting from AMPK or Tfeb inactivation blunted Wnt signaling, while up-regulating this pathway restored expression of endodermal markers. Collectively, these results uncover the AMPK pathway as a novel regulator of cell fate determination during differentiation. © 2016 Young et al.; Published by Cold Spring Harbor Laboratory Press.

Specification of epibranchial placodes in zebrafish.

PubMed

Nechiporuk, Alexei; Linbo, Tor; Poss, Kenneth D; Raible, David W

2007-02-01

In all vertebrates, the neurogenic placodes are transient ectodermal thickenings that give rise to sensory neurons of the cranial ganglia. Epibranchial (EB) placodes generate neurons of the distal facial, glossopharyngeal and vagal ganglia, which convey sensation from the viscera, including pharyngeal endoderm structures, to the CNS. Recent studies have implicated signals from pharyngeal endoderm in the initiation of neurogenesis from EB placodes; however, the signals underlying the formation of placodes are unknown. Here, we show that zebrafish embryos mutant for fgf3 and fgf8 do not express early EB placode markers, including foxi1 and pax2a. Mosaic analysis demonstrates that placodal cells must directly receive Fgf signals during a specific crucial period of development. Transplantation experiments and mutant analysis reveal that cephalic mesoderm is the source of Fgf signals. Finally, both Fgf3 and Fgf8 are sufficient to induce foxi1-positive placodal precursors in wild-type as well as Fgf3-plus Fgf8-depleted embryos. We propose a model in which mesoderm-derived Fgf3 and Fgf8 signals establish both the EB placodes and the development of the pharyngeal endoderm, the subsequent interaction of which promotes neurogenesis. The coordinated interplay between craniofacial tissues would thus assure proper spatial and temporal interactions in the shaping of the vertebrate head.

Apical and basal epitheliomuscular F-actin dynamics during Hydra bud evagination

PubMed Central

Aufschnaiter, Roland; Wedlich-Söldner, Roland; Zhang, Xiaoming

2017-01-01

ABSTRACT Bending of 2D cell sheets is a fundamental morphogenetic mechanism during animal development and reproduction. A critical player driving cell shape during tissue bending is the actin cytoskeleton. Much of our current knowledge about actin dynamics in whole organisms stems from studies of embryonic development in bilaterian model organisms. Here, we have analyzed actin-based processes during asexual bud evagination in the simple metazoan Hydra. We created transgenic Hydra strains stably expressing the actin marker Lifeact-GFP in either ectodermal or endodermal epitheliomuscular cells. We then combined live imaging with conventional phalloidin staining to directly follow actin reorganization. Bending of the Hydra epithelial double layer is initiated by a group of epitheliomuscular cells in the endodermal layer. These cells shorten their apical-basal axis and arrange their basal muscle processes in a circular configuration. We propose that this rearrangement generates the initial forces to bend the endoderm towards the ectoderm. Convergent tissue movement in both epithelial layers towards the centre of evagination then leads to elongation and extension of the bud along its new body axis. Tissue movement into the bud is associated with lateral intercalation of epithelial cells, remodelling of apical septate junctions, and rearrangement of basal muscle processes. The work presented here extends the analysis of morphogenetic mechanisms beyond embryonic tissues of model bilaterians. PMID:28630355

Cell tracking supports secondary gastrulation in the moon jellyfish Aurelia.

PubMed

Gold, David A; Nakanishi, Nagayasu; Hensley, Nicholai M; Hartenstein, Volker; Jacobs, David K

2016-11-01

The moon jellyfish Aurelia exhibits a dramatic reorganization of tissue during its metamorphosis from planula larva to polyp. There are currently two competing hypotheses regarding the fate of embryonic germ layers during this metamorphosis. In one scenario, the original endoderm undergoes apoptosis and is replaced by a secondary endoderm derived from ectodermal cells. In the second scenario, both ectoderm and endoderm remain intact through development. In this study, we performed a pulse-chase experiment to trace the fate of larval ectodermal cells. We observed that prior to metamorphosis, ectodermal cells that proliferated early in larval development concentrate at the future oral end of the polyp. During metamorphosis, these cells migrate into the endoderm, extending all the way to the aboral portion of the gut. We therefore reject the hypothesis that larval endoderm remains intact during metamorphosis and provide additional support for the "secondary gastrulation" hypothesis. Aurelia appears to offer the first and only described case where a cnidarian derives its endoderm twice during normal development, adding to a growing body of evidence that germ layers can be dramatically reorganized in cnidarian life cycles.

A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum.

PubMed

Jia, P; Zhang, C; Huang, X P; Poda, M; Akbas, F; Lemanski, S L; Erginel-Unaltuna, N; Lemanski, L F

2008-11-01

The discovery of the naturally occurring cardiac non-function (c) animal strain in Ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. In homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. We have previously cloned a partial sequence of a peptide cDNA (N1) from an anterior-endoderm-conditioned-medium RNA library that had been shown to be able to rescue the mutant phenotype. In the current studies we have fully cloned the N1 full length cDNA sequence from the library. N1 protein has been detected in both adult heart and skeletal muscle but not in any other adult tissues. GFP-tagged expression of the N1 protein has revealed localization of the N1 protein in the endoplasmic reticulum (ER). Results from in situ hybridization experiments have confirmed the dramatic decrease of expression of N1 mRNA in mutant (c/c) embryos indicating that the N1 gene is involved in heart development.

VEGF and IHH rescue definitive hematopoiesis in Gata-4 and Gata-6-deficient murine embryoid bodies.

PubMed

Pierre, Monique; Yoshimoto, Momoko; Huang, Lan; Richardson, Matthew; Yoder, Mervin C

2009-09-01

Murine embryonic stem cells can be differentiated into embryoid bodies (EBs), which serve as an in vitro model recapitulating many aspects of embryonic yolk sac hematopoiesis. Differentiation of embryonic stem cells deficient in either Gata-4 or Gata-6 results in EBs with disrupted visceral endoderm (VE). While lack of VE has detrimental effects on hematopoiesis in vivo, it is unclear whether lack of VE affects hematopoiesis in EBs. Therefore, we compared Gata-4 null (G4N) and Gata-6 null (G6N) EBs with wild-type EBs to assess their ability to commit to hematopoietic cells. EB VE formation was examined using cell-sorting techniques and analysis visceral endoderm gene expression. Hematopoietic progenitor potential of EBs cultured under various conditions was assessed using colony-forming assays. Definitive erythroid, granulocyte-macrophage, and mixed colonies were significantly reduced in G4N and G6N EBs compared to wild-type EBs. Vascular endothelial growth factor (VEGF) expression and secretion were also reduced in both G4N and G6N EBs, consistent with VE serving as a site of VEGF production. Addition of exogenous VEGF(165), to EB cultures completely rescued definitive colony-forming cells in G4N and G6N EBs. This rescue response could be blocked by addition of soluble Flk-1 Fc to EB cultures. Similarly, addition of exogenous Indian hedgehog to EB cultures also recovers the diminishment in definitive hematopoiesis in a reversible manner. These results suggest that the absence of VE in G4N and G6N EBs does not prevent emergence of definitive progenitors from EBs. However, the decreased level of VEGF and Indian hedgehog production in VE devoid G4N and G6N EBs attenuates definitive hematopoietic progenitor cell expansion.

Characterization and expression analysis of Galnts in developing Strongylocentrotus purpuratus embryos

PubMed Central

Famiglietti, Amber L.; Wei, Zheng; Beres, Thomas M.; Milac, Adina L.; Tran, Duy T.; Patel, Divya; Angerer, Robert C.; Angerer, Lynne M.

2017-01-01

Mucin-type O-glycosylation is a ubiquitous posttranslational modification in which N-Acetylgalactosamine (GalNAc) is added to the hydroxyl group of select serine or threonine residues of a protein by the family of UDP-GalNAc:Polypeptide N-Acetylgalactosaminyltransferases (GalNAc-Ts; EC 2.4.1.41). Previous studies demonstrate that O-glycosylation plays essential roles in protein function, cell-cell interactions, cell polarity and differentiation in developing mouse and Drosophila embryos. Although this type of protein modification is highly conserved among higher eukaryotes, little is known about this family of enzymes in echinoderms, basal deuterostome relatives of the chordates. To investigate the potential role of GalNAc-Ts in echinoderms, we have begun the characterization of this enzyme family in the purple sea urchin, S. purpuratus. We have fully or partially cloned a total of 13 genes (SpGalnts) encoding putative sea urchin SpGalNAc-Ts, and have confirmed enzymatic activity of five recombinant proteins. Amino acid alignments revealed high sequence similarity among sea urchin and mammalian glycosyltransferases, suggesting the presence of putative orthologues. Structural models underscored these similarities and helped reconcile some of the substrate preferences observed. Temporal and spatial expression of SpGalnt transcripts, was studied by whole-mount in situ hybridization. We found that many of these genes are transcribed early in developing embryos, often with restricted expression to the endomesodermal region. Multicolor fluorescent in situ hybridization (FISH) demonstrated that transcripts encoding SpGalnt7-2 co-localized with both Endo16 (a gene expressed in the endoderm), and Gcm (a gene expressed in secondary mesenchyme cells) at the early blastula stage, 20 hours post fertilization (hpf). At late blastula stage (28 hpf), SpGalnt7-2 message co-expresses with Gcm, suggesting that it may play a role in secondary mesenchyme development. We also discovered that morpholino-mediated knockdown of SpGalnt13 transcripts, results in a deficiency of embryonic skeleton and neurons, suggesting that mucin-type O-glycans play essential roles during embryonic development in S. purpuratus. PMID:28448610

Prospectively isolated NGN3-expressing progenitors from human embryonic stem cells give rise to pancreatic endocrine cells.

PubMed

Cai, Qing; Bonfanti, Paola; Sambathkumar, Rangarajan; Vanuytsel, Kim; Vanhove, Jolien; Gysemans, Conny; Debiec-Rychter, Maria; Raitano, Susanna; Heimberg, Harry; Ordovas, Laura; Verfaillie, Catherine M

2014-04-01

Pancreatic endocrine progenitors obtained from human embryonic stem cells (hESCs) represent a promising source to develop cell-based therapies for diabetes. Although endocrine pancreas progenitor cells have been isolated from mouse pancreata on the basis of Ngn3 expression, human endocrine progenitors have not been isolated yet. As substantial differences exist between human and murine pancreas biology, we investigated whether it is possible to isolate pancreatic endocrine progenitors from differentiating hESC cultures by lineage tracing of NGN3. We targeted the 3' end of NGN3 using zinc finger nuclease-mediated homologous recombination to allow selection of NGN3eGFP(+) cells without disrupting the coding sequence of the gene. Isolated NGN3eGFP(+) cells express PDX1, NKX6.1, and chromogranin A and differentiate in vivo toward insulin, glucagon, and somatostatin single hormone-expressing cells but not to ductal or exocrine pancreatic cells or other endodermal, mesodermal, or ectodermal lineages. This confirms that NGN3(+) cells represent pancreatic endocrine progenitors in humans. In addition, this hESC reporter line constitutes a unique tool that may aid in gaining insight into the developmental mechanisms underlying fate choices in human pancreas and in developing cell-based therapies.

Loss of PiT-1 Results in Abnormal Endocytosis in the Yolk Sac Visceral Endoderm

PubMed Central

Wallingford, Mary C.; Giachelli, Cecilia M.

2014-01-01

PiT-1 protein is a transmembrane sodium-dependent phosphate (Pi) transporter. PiT-1 knock out (KO) embryos die from largely unknown causes by embryonic day (E) 12.5. We tested the hypothesis that PiT-1 is required for endocytosis in the embryonic yolk sac (YS) visceral endoderm (VE). Here we present data supporting that PiT-1 KO results in a YS remodeling defect and decreased endocytosis in the YS VE. The remodeling defect is not due to an upstream cardiomyocyte requirement for PiT-1, as SM22αCre-specific KO of PiT-1 in the developing heart and the YS mesodermal layer (ME) does not recapitulate the PiT-1 global KO phenotype. Furthermore, we find that high levels of PiT-1 protein localize to the YS VE apical membrane. Together these data support that PiT-1 is likely required in YS VE. During normal development maternal immunoglobulin (IgG) is endocytosed into YS VE and accumulates in the apical side of the VE in a specialized lysosome termed the apical vacuole (AV). We have identified a reduction in PiT-1 KO VE cell height and a striking loss of IgG accumulation in the PiT-1 KO VE. The endocytosis genes Tfeb, Lamtor2 and Snx2 are increased at the RNA level. Lysotracker Red staining reveals a loss of distinct AVs, and yolk sacs incubated ex vivo with phRODO Green Dextran for Endocytosis demonstrate a functional loss of endocytosis. As yolk sac endocytosis is controlled in part by microautophagy, but expression of LC3 had not been examined, we investigated LC3 expression during yolk sac development and found stage-specific LC3 RNA expression that is predominantly from the YS VE layer at E9.5. Normalized LC3-II protein levels are decreased in the PiT-1 KO YS, supporting a requirement for PiT-1 in autophagy in the YS. Therefore, we propose the novel idea that PiT-1 is central to the regulation of endocytosis and autophagy in the YS VE. PMID:25138534

The forkhead transcription factor Foxf1 is required for differentiation of extra-embryonic and lateral plate mesoderm.

PubMed

Mahlapuu, M; Ormestad, M; Enerbäck, S; Carlsson, P

2001-01-01

The murine Foxf1 gene encodes a forkhead transcription factor expressed in extra-embryonic and lateral plate mesoderm and later in splanchnic mesenchyme surrounding the gut and its derivatives. We have disrupted Foxf1 and show that mutant embryos die at midgestation due to defects in mesodermal differentiation and cell adhesion. The embryos do not turn and become deformed by the constraints of a small, inflexible amnion. Extra-embryonic structures exhibit a number of differentiation defects: no vasculogenesis occurs in yolk sac or allantois; chorioallantoic fusion fails; the amnion does not expand with the growth of the embryo, but misexpresses vascular and hematopoietic markers. Separation of the bulk of yolk sac mesoderm from the endodermal layer and adherence between mesoderm of yolk sac and amnion, indicate altered cell adhesion properties and enhanced intramesodermal cohesion. A possible cause of this is misexpression of the cell-adhesion protein VCAM1 in Foxf1-deficient extra-embryonic mesoderm, which leads to co-expression of VCAM with its receptor, alpha(4)-integrin. The expression level of Bmp4 is decreased in the posterior part of the embryo proper. Consistent with this, mesodermal proliferation in the primitive streak is reduced and somite formation is retarded. Expression of Foxf1 and the homeobox gene Irx3 defines the splanchnic and somatic mesodermal layers, respectively. In Foxf1-deficient embryos incomplete separation of splanchnic and somatic mesoderm is accompanied by misexpression of Irx3 in the splanchnopleure, which implicates Foxf1 as a repressor of Irx3 and as a factor involved in coelom formation.

Head formation: OTX2 regulates Dkk1 and Lhx1 activity in the anterior mesendoderm.

PubMed

Ip, Chi Kin; Fossat, Nicolas; Jones, Vanessa; Lamonerie, Thomas; Tam, Patrick P L

2014-10-01

The Otx2 gene encodes a paired-type homeobox transcription factor that is essential for the induction and the patterning of the anterior structures in the mouse embryo. Otx2 knockout embryos fail to form a head. Whereas previous studies have shown that Otx2 is required in the anterior visceral endoderm and the anterior neuroectoderm for head formation, its role in the anterior mesendoderm (AME) has not been assessed specifically. Here, we show that tissue-specific ablation of Otx2 in the AME phenocopies the truncation of the embryonic head of the Otx2 null mutant. Expression of Dkk1 and Lhx1, two genes that are also essential for head formation, is disrupted in the AME of the conditional Otx2-deficient embryos. Consistent with the fact that Dkk1 is a direct target of OTX2, we showed that OTX2 can interact with the H1 regulatory region of Dkk1 to activate its expression. Cross-species comparative analysis, RT-qPCR, ChIP-qPCR and luciferase assays have revealed two conserved regions in the Lhx1 locus to which OTX2 can bind to activate Lhx1 expression. Abnormal development of the embryonic head in Otx2;Lhx1 and Otx2;Dkk1 compound mutant embryos highlights the functional intersection of Otx2, Dkk1 and Lhx1 in the AME for head formation. © 2014. Published by The Company of Biologists Ltd.

Early development of zooxanthella-containing eggs of the corals Porites cylindrica and Montipora digitata: The endodermal localization of zooxanthellae.

PubMed

Hirose, Mamiko; Hidaka, Michio

2006-10-01

We studied the early development of zooxanthellae-containing eggs of the scleractinian corals Porites cylindrica and Montipora digitata to elucidate how zooxanthellae become localized to the endoderm of planulae during the course of development. In both species, zooxanthellae were distributed evenly in the oocytes and delivered almost equally to the blastomeres during cleavage. In P. cylindrica, gastrulation occurred via delamination or ingression, and blastomeres containing zooxanthellae dropped into the blastocoel during gastrulation. Thus, zooxanthellae were restricted to the endodermal cells at the gastrula or early planula stage in P. cylindrica. In M. digitata, gastrulation occurred by a combination of invagination and epiboly to form a somewhat concave gastrula. Zooxanthellae were present in both endodermal and ectodermal cells of early planulae, but they disappeared from the ectoderm as the planulae matured. In our previous study on two species of Pocillopora, we found that zooxanthellae were localized in eggs as well as in embryos, and that blastomeres containing zooxanthellae later dropped into the blastocoel to become restricted to the endoderm (Hirose et al., 2000). The timing and mechanism of zooxanthella localization and types of gastrulation differed among species belonging to the three genera. These results suggest that zooxanthella localization in the embryos reflects the timing of the determination of presumptive endoderm cells and/or specificity of zooxanthellae toward presumptive endoderm cells.

Expression of hLAMP-1-Positive Particles During Early Heart Development in the Chick.

PubMed

Abd-Elhamid, T H; Conway, M L; Sinning, A R

2017-10-01

Heart development requires coordinated activity of various factors, the disturbance of which can lead to congenital heart defects. Heart lectin-associated matrix protein-1 (hLAMP-1) is a matrix protein expressed within Hensen's node at Hamburger-Hamilton (HH) stage 4, in the lateral mesoderm by HH stages 5-6 and enhanced within the left pre-cardiac field at HH stage 7. At HH stages 15-16, hLAMP-1 expression is observed in the atrioventricular canal and the outflow tract. Also, the role of hLAMP-1 in induction of mesenchyme formation in chick heart has been well documented. To further elucidate the role of this molecule in heart development, we examined its expression patterns during HH stages 8-14 in the chick. In this regard, we immunostained sections of the heart during HH stages 8-14 with antibodies specific to hLAMP-1. Our results showed prominent expression of hLAMP-1-positive particles in the extracellular matrix associated with the pre-cardiac mesoderm, the endoderm, ectoderm as well as neuroectoderm at HH stages 8-9. After formation of the linear heart tube at HH stage 10, the expression of hLAMP-1-stained particles disappears in those regions of original contact between the endoderm and heart forming fields due to rupture of the dorsal mesocardium while their expression becomes confined to the arterial and venous poles of the heart tube. This expression pattern is maintained until HH stage 14. This expression pattern suggests that hLAMP-1 may be involved in the formation of the endocardial tube. © 2017 Blackwell Verlag GmbH.

Regulation of Six1 expression by evolutionarily conserved enhancers in tetrapods.

PubMed

Sato, Shigeru; Ikeda, Keiko; Shioi, Go; Nakao, Kazuki; Yajima, Hiroshi; Kawakami, Kiyoshi

2012-08-01

The Six1 homeobox gene plays critical roles in vertebrate organogenesis. Mice deficient for Six1 show severe defects in organs such as skeletal muscle, kidney, thymus, sensory organs and ganglia derived from cranial placodes, and mutations in human SIX1 cause branchio-oto-renal syndrome, an autosomal dominant developmental disorder characterized by hearing loss and branchial defects. The present study was designed to identify enhancers responsible for the dynamic expression pattern of Six1 during mouse embryogenesis. The results showed distinct enhancer activities of seven conserved non-coding sequences (CNSs) retained in tetrapod Six1 loci. The activities were detected in all cranial placodes (excluding the lens placode), dorsal root ganglia, somites, nephrogenic cord, notochord and cranial mesoderm. The major Six1-expression domains during development were covered by the sum of activities of these enhancers, together with the previously identified enhancer for the pre-placodal region and foregut endoderm. Thus, the eight CNSs identified in a series of our study represent major evolutionarily conserved enhancers responsible for the expression of Six1 in tetrapods. The results also confirmed that chick electroporation is a robust means to decipher regulatory information stored in vertebrate genomes. Mutational analysis of the most conserved placode-specific enhancer, Six1-21, indicated that the enhancer integrates a variety of inputs from Sox, Pax, Fox, Six, Wnt/Lef1 and basic helix-loop-helix proteins. Positive autoregulation of Six1 is achieved through the regulation of Six protein-binding sites. The identified Six1 enhancers provide valuable tools to understand the mechanism of Six1 regulation and to manipulate gene expression in the developing embryo, particularly in the sensory organs. Copyright © 2012 Elsevier Inc. All rights reserved.

WNT signaling in stem cell biology and regenerative medicine.

PubMed

Katoh, Masaru

2008-07-01

WNT family members are secreted-type glycoproteins to orchestrate embryogenesis, to maintain homeostasis, and to induce pathological conditions. FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, FZD10, LRP5, LRP6, and ROR2 are transmembrane receptors transducing WNT signals based on ligand-dependent preferentiality for caveolin- or clathrin-mediated endocytosis. WNT signals are transduced to canonical pathway for cell fate determination, and to non-canonical pathways for regulation of planar cell polarity, cell adhesion, and motility. MYC, CCND1, AXIN2, FGF20, WISP1, JAG1, DKK1 and Glucagon are target genes of canonical WNT signaling cascade, while CD44, Vimentin and STX5 are target genes of non-canonical WNT signaling cascades. However, target genes of WNT signaling cascades are determined in a context-dependent manner due to expression profile of transcription factors and epigenetic status. WNT signaling cascades network with Notch, FGF, BMP and Hedgehog signaling cascades to regulate the balance of stem cells and progenitor cells. Here WNT signaling in embryonic stem cells, neural stem cells, mesenchymal stem cells, hematopoietic stem cells, and intestinal stem cells will be reviewed. WNT3, WNT5A and WNT10B are expressed in undifferentiated human embryonic stem cells, while WNT6, WNT8B and WNT10B in endoderm precursor cells. Wnt6 is expressed in intestinal crypt region for stem or progenitor cells. TNF/alpha-WNT10B signaling is a negative feedback loop to maintain homeostasis of adipose tissue and gastrointestinal mucosa with chronic inflammation. Recombinant WNT protein or WNT mimetic (circular peptide, small molecule compound, or RNA aptamer) in combination with Notch mimetic, FGF protein, and BMP protein opens a new window to tissue engineering for regenerative medicine.

Inositol-requiring enzyme 1α is required for gut development in Xenopus lavies embryos

PubMed Central

Guo, Jing; Li, Xin-Xin; Feng, Jiao-Jiao; Yin, Chen-Yang; Wang, Xue-Jun; Wang, Ning; Yuan, Li

2013-01-01

AIM: To investigate the role of inositol-requiring enzyme 1α (IRE1α) in gut development of Xenopus lavies embryos. METHODS: Xenopus embryos were obtained with in vitro fertilization and cultured in 0.1 × MBSH. One and half nanogram of IRE1α, 1 ng of IRE1α-GR mRNA, 1 ng of IRE1αΔC-GR mRNA, and 50 ng of IRE1α morpholino oligonucleotide (MO) or XBP1(C)MO were injected into four blastomeres at 4-cell stage for scoring the phenotype and marker gene analysis. To rescue the effect of IRE1α MO, 1 ng of IRE1α-GR mRNA was co-injected with 50 ng of MO. For the activation of the GR-fusion proteins, dexamethasone was prepared as 5 mmol/L stock solutions in 100% ethanol and applied to the mRNA injected embryos at desired stages in a concentration of 10 μmol/L in 0.1 × MBSH. Embryos were kept in dexamethasone up to stage 41. Whole-mount in situ hybridization was used to determine specific gene expression, such as IRE1α, IRE1β, Xbra and Xsox17α. IRE1α protein expression during Xenopus embryogenesis was detected by Western blotting. RESULTS: In the whole-mount in situ hybridization analysis, xenopus IRE1α and IRE1β showed quite different expression pattern during tadpole stage. The relatively higher expression of IRE1α was observed in the pancreas, and significant transcription of IRE1β was found in the liver. IRE1α protein could be detected at all developmental stages analyzed, from stage 1 to stage 42. Gain-of-function assay showed that IRE1α mRNA injected embryos at tailbud stage were nearly normal and the expression of the pan-mesodermal marker gene Xbra and the endodermal gene Xsox17α at stage 10.5 was not significantly changed in embryos injected with IRE1α mRNA as compared to uninjected control embryos. And at tadpole stage, the embryos injected with IRE1α-GR mRNA did not display overt phenotype, such as gut-coiling defect. Loss-of-function assay demonstrated that the IRE1α MO injected embryos were morphologically normal before the tailbud stages. We did not observe a significant change of mesodermal and endodermal marker gene expression, while after stage 40, about 80% of the MO injected embryos exhibited dramatic gut defects in which the guts did not coil, but other structures outside the gastrointestinal tract were relatively normal. To test if the phenotypes were specifically caused by the knockdown of IRE1α, a rescue experiment was performed by co-injection of IRE1α-GR mRMA with IRE1α MO. The data obtained demonstrated that the gut coiling defect was rescued. The deletion mutant of IRE1α was constructed, consisting of the N-terminal part without the C-terminal kinase and RNase domains named IRE1αΔC, to investigate the functional domain of IRE1α. Injection of IRE1αΔC-GR mRNA caused similar morphological alterations with gut malformation by interfering with the function of endogenous xIRE1α. In order to investigate if IRE1α/XBP1 pathway was involved in gut development, 50 ng of XBP1 MO was injected and the results showed that knockdown of XBP1 resulted in similar morphological alterations with gut-coiling defect at tadpole stage. CONCLUSION: IRE1α is not required for germ layer formation but for gut development in Xenopus lavies and it may function via XBP1-dependent pathway. PMID:23345945

Inositol-requiring enzyme 1α is required for gut development in Xenopus lavies embryos.

PubMed

Guo, Jing; Li, Xin-Xin; Feng, Jiao-Jiao; Yin, Chen-Yang; Wang, Xue-Jun; Wang, Ning; Yuan, Li

2013-01-14

To investigate the role of inositol-requiring enzyme 1α (IRE1α) in gut development of Xenopus lavies embryos. Xenopus embryos were obtained with in vitro fertilization and cultured in 0.1 × MBSH. One and half nanogram of IRE1α, 1 ng of IRE1α-GR mRNA, 1 ng of IRE1αΔC-GR mRNA, and 50 ng of IRE1α morpholino oligonucleotide (MO) or XBP1(C)MO were injected into four blastomeres at 4-cell stage for scoring the phenotype and marker gene analysis. To rescue the effect of IRE1α MO, 1 ng of IRE1α-GR mRNA was co-injected with 50 ng of MO. For the activation of the GR-fusion proteins, dexamethasone was prepared as 5 mmol/L stock solutions in 100% ethanol and applied to the mRNA injected embryos at desired stages in a concentration of 10 μmol/L in 0.1 × MBSH. Embryos were kept in dexamethasone up to stage 41. Whole-mount in situ hybridization was used to determine specific gene expression, such as IRE1α, IRE1β, Xbra and Xsox17α. IRE1α protein expression during Xenopus embryogenesis was detected by Western blotting. In the whole-mount in situ hybridization analysis, xenopus IRE1α and IRE1β showed quite different expression pattern during tadpole stage. The relatively higher expression of IRE1α was observed in the pancreas, and significant transcription of IRE1β was found in the liver. IRE1α protein could be detected at all developmental stages analyzed, from stage 1 to stage 42. Gain-of-function assay showed that IRE1α mRNA injected embryos at tailbud stage were nearly normal and the expression of the pan-mesodermal marker gene Xbra and the endodermal gene Xsox17α at stage 10.5 was not significantly changed in embryos injected with IRE1α mRNA as compared to uninjected control embryos. And at tadpole stage, the embryos injected with IRE1α-GR mRNA did not display overt phenotype, such as gut-coiling defect. Loss-of-function assay demonstrated that the IRE1α MO injected embryos were morphologically normal before the tailbud stages. We did not observe a significant change of mesodermal and endodermal marker gene expression, while after stage 40, about 80% of the MO injected embryos exhibited dramatic gut defects in which the guts did not coil, but other structures outside the gastrointestinal tract were relatively normal. To test if the phenotypes were specifically caused by the knockdown of IRE1α, a rescue experiment was performed by co-injection of IRE1α-GR mRMA with IRE1α MO. The data obtained demonstrated that the gut coiling defect was rescued. The deletion mutant of IRE1α was constructed, consisting of the N-terminal part without the C-terminal kinase and RNase domains named IRE1αΔC, to investigate the functional domain of IRE1α. Injection of IRE1αΔC-GR mRNA caused similar morphological alterations with gut malformation by interfering with the function of endogenous xIRE1α. In order to investigate if IRE1α/XBP1 pathway was involved in gut development, 50 ng of XBP1 MO was injected and the results showed that knockdown of XBP1 resulted in similar morphological alterations with gut-coiling defect at tadpole stage. IRE1α is not required for germ layer formation but for gut development in Xenopus lavies and it may function via XBP1-dependent pathway.

A genomic regulatory network for development

NASA Technical Reports Server (NTRS)

Davidson, Eric H.; Rast, Jonathan P.; Oliveri, Paola; Ransick, Andrew; Calestani, Cristina; Yuh, Chiou-Hwa; Minokawa, Takuya; Amore, Gabriele; Hinman, Veronica; Arenas-Mena, Cesar;

YKL-40 is differentially expressed in human embryonic stem cells and in cell progeny of the three germ layers.

PubMed

Brøchner, Christian B; Johansen, Julia S; Larsen, Lars A; Bak, Mads; Mikkelsen, Hanne B; Byskov, Anne Grete; Andersen, Claus Yding; Møllgård, Kjeld

2012-03-01

The secreted glycoprotein YKL-40 participates in cell differentiation, inflammation, and cancer progression. High YKL-40 expression is reported during early human development, but its functions are unknown. Six human embryonic stem cell (hESC) lines were cultured in an atmosphere of low or high oxygen tension, in culture medium with or without basic fibroblast growth factor, and on feeder layers comprising mouse embryonic fibroblasts or human foreskin fibroblasts to evaluate whether hESCs and their progeny produced YKL-40 and to characterize YKL-40 expression during differentiation. Secreted YKL-40 protein and YKL-40 mRNA expression were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative RT-PCR. Serial-sectioned colonies were stained for YKL-40 protein and for pluripotent hESC (OCT4, NANOG) and germ layer (HNF-3β, PDX1, CD34, p63, nestin, PAX6) markers. Double-labeling showed YKL-40 expression in OCT4-positive hESCs, PAX6-positive neuroectodermal cells, and HNF-3β-positive endodermal cells. The differentiating progeny showed strong YKL-40 expression. Abrupt transition between YKL-40 and OCT4-positive hESCs and YKL-40-positive ecto- and neuroectodermal lineages was observed within the same epithelial-like layer. YKL-40-positive cells within deeper layers lacked contact with OCT4-positive cells. YKL-40 may be important in initial cell differentiation from hESCs toward ectoderm and neuroectoderm, with retained epithelial morphology, whereas later differentiation into endoderm and mesoderm involves a transition into the deeper layers of the colony.

Regulation of mouse stomach development and Barx1 expression by specific microRNAs

PubMed Central

Kim, Byeong-Moo; Woo, Janghee; Kanellopoulou, Chryssa; Shivdasani, Ramesh A.

2011-01-01

Although microRNAs (miRNAs) are postulated to fine-tune many developmental processes, their relationships with specific targets and tissues remain largely undefined. The mesenchymal transcription factor Barx1 controls spleen and stomach morphogenesis and is required to specify stomach-specific epithelium in adjacent endoderm. Barx1 expression is precisely regulated in space and time, with a sharp drop in stomach levels after epithelial specification. We tested the hypothesis that specific miRNAs mediate this marked decline in Barx1 levels. Depletion of the miRNA-processing enzyme Dicer in cultured stomach mesenchyme and conditional Dicer gene deletion in mice significantly increased Barx1 levels, disrupted stomach and intestine development and caused spleen agenesis. Computational and experimental studies identified miR-7a and miR-203 as candidate miRNAs that regulate Barx1 and are expressed in inverse proportion to it in the fetal mouse stomach. Through specific interactions with cognate sequences in the Barx1 3′ untranslated region, miR-7a and miR-203 repress Barx1 expression in stomach mesenchymal cells and its function in inducing gastric epithelium. These results indicate that miRNAs are required for proper digestive tract organogenesis and that miR-7a and miR-203 control expression of the stomach homeotic regulator Barx1. PMID:21307095

Three methods for isolating viable anthozoan endoderm cells with their intracellular symbiotic dinoflagellates

NASA Astrophysics Data System (ADS)

Gates, R. D.; Muscatine, L.

1992-09-01

Three maceration methods are described for the isolation of single endoderm cells from marine cnidarians. Two are enzymatic treatments suitable for fleshy anthozoans such as sea anemones and zoanthids. The third employs calcium free sea water and is suitable for stony corals. The viability and morphology of the endoderm cells is described using fluorogenic dyes and scanning and transmission electron microscopy.

Characterization of NvLWamide-like neurons reveals stereotypy in Nematostella nerve net development.

PubMed

Havrilak, Jamie A; Faltine-Gonzalez, Dylan; Wen, Yiling; Fodera, Daniella; Simpson, Ayanna C; Magie, Craig R; Layden, Michael J

2017-11-15

The organization of cnidarian nerve nets is traditionally described as diffuse with randomly arranged neurites that show minimal reproducibility between animals. However, most observations of nerve nets are conducted using cross-reactive antibodies that broadly label neurons, which potentially masks stereotyped patterns produced by individual neuronal subtypes. Additionally, many cnidarians species have overt structures such as a nerve ring, suggesting higher levels of organization and stereotypy exist, but mechanisms that generated that stereotypy are unknown. We previously demonstrated that NvLWamide-like is expressed in a small subset of the Nematostella nerve net and speculated that observing a few neurons within the developing nerve net would provide a better indication of potential stereotypy. Here we document NvLWamide-like expression more systematically. NvLWamide-like is initially expressed in the typical neurogenic salt and pepper pattern within the ectoderm at the gastrula stage, and expression expands to include endodermal salt and pepper expression at the planula larval stage. Expression persists in both ectoderm and endoderm in adults. We characterized our NvLWamide-like::mCherry transgenic reporter line to visualize neural architecture and found that NvLWamide-like is expressed in six neural subtypes identifiable by neural morphology and location. Upon completing development the numbers of neurons in each neural subtype are minimally variable between animals and the projection patterns of each subtype are consistent. Furthermore, between the juvenile polyp and adult stages the number of neurons for each subtype increases. We conclude that development of the Nematostella nerve net is stereotyped between individuals. Our data also imply that one aspect of generating adult cnidarian nervous systems is to modify the basic structural architecture generated in the juvenile by increasing neural number proportionally with size. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Tissue-specific Requirements of β-Catenin in External Genitalia Development

PubMed Central

Lin, Congxing; Yin, Yan; Long, Fanxin; Ma, Liang

2008-01-01

SUMMARY External genitalia are body appendages specialized for internal fertilization. Its development can be divided into two phases, an early androgen-independent phase and a late androgen-dependant sexual differentiation phase. In the early phase, the embryonic anlage of external genitalia, the genital tubercle (GT), are morphologically identical in both sexes. Although congenital external genitalia malformations represent the second most common birth defect in humans, the genetic pathways governing early external genitalia development and urethra formation are poorly understood. Proper development of the GT requires coordinated outgrowth of the mesodermally-derived mesenchyme and extension of the endodermal urethra within an ectodermal epithelial capsule. Here we demonstrate that β-Catenin plays indispensable and distinct roles in each of the aforementioned three tissue layers in early androgen-independent GT development. WNT-β-Catenin signaling is required in the endodermal urethra to activate and maintain Fgf8 expression and direct GT outgrowth, as well as to maintain homeostasis of the urethra. Moreover, β-Catenin is required in the mesenchyme to promote cell proliferation. In contrast, β-Catenin is required in the ectoderm to maintain tissue integrity possibly through cell-cell adhesion during GT outgrowth. The fact that both endodermal and ectodermal β-Catenin knockout animals develop severe hypospadias in both sexes raises the possibility that deregulation of any of these functions can contribute to the etiology of congenital external genital defects in humans. PMID:18635608

Improvement of Cell Survival During Human Pluripotent Stem Cell Definitive Endoderm Differentiation

PubMed Central

Wang, Han; Luo, Xie; Yao, Li; Lehman, Donna M.

2015-01-01

Definitive endoderm (DE) is a vital precursor for internal organs such as liver and pancreas. Efficient protocol to differentiate human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPSCs) to DE is essential for regenerative medicine and for modeling diseases; yet, poor cell survival during DE differentiation remains unsolved. In this study, our use of B27 supplement in modified differentiation protocols has led to a substantial improvement. We used an SOX17-enhanced green fluorescent protein (eGFP) reporter hESC line to compare and modify established DE differentiation protocols. Both total live cell numbers and the percentages of eGFP-positive cells were used to assess differentiation efficiency. Among tested protocols, three modified protocols with serum-free B27 supplement were developed to generate a high number of DE cells. Massive cell death was avoided during DE differentiation and the percentage of DE cells remained high. When the resulting DE cells were further differentiated toward the pancreatic lineage, the expression of pancreatic-specific markers was significantly increased. Similar high DE differentiation efficiency was observed in H1 hESCs and iPSCs through the modified protocols. In B27 components, bovine serum albumin was found to facilitate DE differentiation and cell survival. Using our modified DE differentiation protocols, satisfactory quantities of quality DE can be produced as primary material for further endoderm lineage differentiation. PMID:26132288

Induction of Pancreatic Differentiation by Signals from Blood Vessels

NASA Astrophysics Data System (ADS)

Lammert, Eckhard; Cleaver, Ondine; Melton, Douglas

2001-10-01

Blood vessels supply developing organs with metabolic sustenance. Here, we demonstrate a role for blood vessels as a source of developmental signals during pancreatic organogenesis. In vitro experiments with embryonic mouse tissues demonstrate that blood vessel endothelium induces insulin expression in isolated endoderm. Removal of the dorsal aorta in Xenopus laevis embryos results in the failure of insulin expression in vivo. Furthermore, using transgenic mice, we show that ectopic vascularization in the posterior foregut leads to ectopic insulin expression and islet hyperplasia. These results indicate that vessels not only provide metabolic sustenance, but also provide inductive signals for organ development.

Prostaglandin E2 Regulates Liver versus Pancreas Cell Fate Decisions and Endodermal Outgrowth

PubMed Central

Nissim, Sahar; Sherwood, Richard I.; Wucherpfennig, Julia; Saunders, Diane; Harris, James M.; Esain, Virginie; Carroll, Kelli J.; Frechette, Gregory M.; Kim, Andrew J.; Hwang, Katie L.; Cutting, Claire C.; Elledge, Susanna; North, Trista E.; Goessling, Wolfram

2014-01-01

SUMMARY The liver and pancreas arise from common endodermal progenitors. How these distinct cell fates are specified is poorly understood. Here, we describe prostaglandin E2 (PGE2) as a regulator of endodermal fate specification during development. Modulating PGE2 activity has opposing effects on liver-versus-pancreas specification in zebrafish embryos as well as mouse endodermal progenitors. The PGE2 synthetic enzyme cox2a and receptor ep2a are patterned such that cells closest to PGE2 synthesis acquire a liver fate whereas more distant cells acquire a pancreas fate. PGE2 interacts with the bmp2b pathway to regulate fate specification. At later stages of development, PGE2 acting via the ep4a receptor promotes outgrowth of both the liver and pancreas. PGE2 remains important for adult organ growth, as it modulates liver regeneration. This work provides in vivo evidence that PGE2 may act as a morphogen to regulate cell fate decisions and outgrowth of the embryonic endodermal anlagen. PMID:24530296

Variable phenotypic penetrance of thrombosis in adult mice after tissue-selective and temporally controlled Thbd gene inactivation

PubMed Central

van Mens, Thijs E.; Liang, Hai-Po H.; Basu, Sreemanti; Hernandez, Irene; Zogg, Mark; May, Jennifer; Zhan, Min; Yang, Qiuhui; Foeckler, Jamie; Kalloway, Shawn; Sood, Rashmi; Karlson, Caren Sue

2017-01-01

Thrombomodulin (Thbd) exerts pleiotropic effects on blood coagulation, fibrinolysis, and complement system activity by facilitating the thrombin-mediated activation of protein C and thrombin-activatable fibrinolysis inhibitor and may have additional thrombin- and protein C (pC)-independent functions. In mice, complete Thbd deficiency causes embryonic death due to defective placental development. In this study, we used tissue-selective and temporally controlled Thbd gene ablation to examine the function of Thbd in adult mice. Selective preservation of Thbd function in the extraembryonic ectoderm and primitive endoderm via the Meox2Cre-transgene enabled normal intrauterine development of Thbd-deficient (Thbd−/−) mice to term. Half of the Thbd−/− offspring expired perinatally due to thrombohemorrhagic lesions. Surviving Thbd−/− animals only rarely developed overt thrombotic lesions, exhibited low-grade compensated consumptive coagulopathy, and yet exhibited marked, sudden-onset mortality. A corresponding pathology was seen in mice in which the Thbd gene was ablated after reaching adulthood. Supplementation of activated PC by transgenic expression of a partially Thbd-independent murine pC zymogen prevented the pathologies of Thbd−/− mice. However, Thbd−/− females expressing the PC transgene exhibited pregnancy-induced morbidity and mortality with near-complete penetrance. These findings suggest that Thbd function in nonendothelial embryonic tissues of the placenta and yolk sac affects through as-yet-unknown mechanisms the penetrance and severity of thrombosis after birth and provide novel opportunities to study the role of the natural Thbd-pC pathway in adult mice and during pregnancy. PMID:28920104

Loss of heme oxygenase-1 accelerates mesodermal gene expressions during embryoid body development from mouse embryonic stem cells.

PubMed

Lai, Yan-Liang; Lin, Chen-Yu; Jiang, Wei-Cheng; Ho, Yen-Chun; Chen, Chung-Huang; Yet, Shaw-Fang

2018-05-01

Heme oxygenase (HO)-1 is an inducible stress response protein and well known to protect cells and tissues against injury. Despite its important function in cytoprotection against physiological stress, the role of HO-1 in embryonic stem cell (ESC) differentiation remains largely unknown. We showed previously that induced pluripotent stem (iPS) cells that lack HO-1 are more sensitive to oxidant stress-induced cell death and more prone to lose pluripotent markers upon LIF withdrawal. To elucidate the role of HO-1 in ESC differentiation and to rule out the controversy of potential gene flaws in iPS cells, we derived and established mouse HO-1 knockout ESC lines from HO-1 knockout blastocysts. Using wild type D3 and HO-1 knockout ESCs in the 3-dimensional embryoid body (EB) differentiation model, we showed that at an early time point during EB development, an absence of HO-1 led to enhanced ROS level, concomitant with increased expressions of master mesodermal regulator brachyury and endodermal marker GATA6. In addition, critical smooth muscle cell (SMC) transcription factor serum response factor and its coactivator myocardin were enhanced. Furthermore, HO-1 deficiency increased Smad2 in ESCs and EBs, revealing a role of HO-1 in controlling Smad2 level. Smad2 not only mediates mesendoderm differentiation of mouse ESCs but also SMC development. Collectively, loss of HO-1 resulted in higher level of mesodermal and SMC regulators, leading to accelerated and enhanced SMC marker SM α-actin expression. Our results reveal a previously unrecognized function of HO-1 in regulating SMC gene expressions during ESC-EB development. More importantly, our findings may provide a novel strategy in enhancing ESC differentiation toward SMC lineage. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

The differential effects of 2% oxygen preconditioning on the subsequent differentiation of mouse and human pluripotent stem cells.

PubMed

Fynes, Kate; Tostoes, Rui; Ruban, Ludmila; Weil, Ben; Mason, Christopher; Veraitch, Farlan S

2014-08-15

A major challenge facing the development of effective cell therapies is the efficient differentiation of pluripotent stem cells (PSCs) into pure populations. Lowering oxygen tension to physiological levels can affect both the expansion and differentiation stages. However, to date, there are no studies investigating the knock-on effect of culturing PSCs under low oxygen conditions on subsequent lineage commitment at ambient oxygen levels. PSCs were passaged three times at 2% O2 before allowing cells to spontaneously differentiate as embryoid bodies (EBs) in high oxygen (20% O2) conditions. Maintenance of mouse PSCs in low oxygen was associated with a significant increase in the expression of early differentiation markers FGF5 and Eomes, while conversely we observed decreased expression of these genes in human PSCs. Low oxygen preconditioning primed mouse PSCs for their subsequent differentiation into mesodermal and endodermal lineages, as confirmed by increased gene expression of Eomes, Goosecoid, Brachyury, AFP, Sox17, FoxA2, and protein expression of Brachyury, Eomes, Sox17, FoxA2, relative to high oxygen cultures. The effects extended to the subsequent formation of more mature mesodermal lineages. We observed significant upregulation of cardiomyocyte marker Nkx2.5, and critically a decrease in the number of contaminant pluripotent cells after 12 days using a directed cardiomyocyte protocol. However, the impact of low oxygen preconditioning was to prime human cells for ectodermal lineage commitment during subsequent EB differentiation, with significant upregulation of Nestin and β3-tubulin. Our research demonstrates the importance of oxygen tension control during cell maintenance on the subsequent differentiation of both mouse and human PSCs, and highlights the differential effects.

Derivation and characterization of hepatic progenitor cells from human embryonic stem cells.

PubMed

Zhao, Dongxin; Chen, Song; Cai, Jun; Guo, Yushan; Song, Zhihua; Che, Jie; Liu, Chun; Wu, Chen; Ding, Mingxiao; Deng, Hongkui

2009-07-31

The derivation of hepatic progenitor cells from human embryonic stem (hES) cells is of value both in the study of early human liver organogenesis and in the creation of an unlimited source of donor cells for hepatocyte transplantation therapy. Here, we report for the first time the generation of hepatic progenitor cells derived from hES cells. Hepatic endoderm cells were generated by activating FGF and BMP pathways and were then purified by fluorescence activated cell sorting using a newly identified surface marker, N-cadherin. After co-culture with STO feeder cells, these purified hepatic endoderm cells yielded hepatic progenitor colonies, which possessed the proliferation potential to be cultured for an extended period of more than 100 days. With extensive expansion, they co-expressed the hepatic marker AFP and the biliary lineage marker KRT7 and maintained bipotential differentiation capacity. They were able to differentiate into hepatocyte-like cells, which expressed ALB and AAT, and into cholangiocyte-like cells, which formed duct-like cyst structures, expressed KRT19 and KRT7, and acquired epithelial polarity. In conclusion, this is the first report of the generation of proliferative and bipotential hepatic progenitor cells from hES cells. These hES cell-derived hepatic progenitor cells could be effectively used as an in vitro model for studying the mechanisms of hepatic stem/progenitor cell origin, self-renewal and differentiation.

Murine craniofacial development requires Hdac3-mediated repression of Msx gene expression.

PubMed

Singh, Nikhil; Gupta, Mudit; Trivedi, Chinmay M; Singh, Manvendra K; Li, Li; Epstein, Jonathan A

2013-05-15

Craniofacial development is characterized by reciprocal interactions between neural crest cells and neighboring cell populations of ectodermal, endodermal and mesodermal origin. Various genetic pathways play critical roles in coordinating the development of cranial structures by modulating the growth, survival and differentiation of neural crest cells. However, the regulation of these pathways, particularly at the epigenomic level, remains poorly understood. Using murine genetics, we show that neural crest cells exhibit a requirement for the class I histone deacetylase Hdac3 during craniofacial development. Mice in which Hdac3 has been conditionally deleted in neural crest demonstrate fully penetrant craniofacial abnormalities, including microcephaly, cleft secondary palate and dental hypoplasia. Consistent with these abnormalities, we observe dysregulation of cell cycle genes and increased apoptosis in neural crest structures in mutant embryos. Known regulators of cell cycle progression and apoptosis in neural crest, including Msx1, Msx2 and Bmp4, are upregulated in Hdac3-deficient cranial mesenchyme. These results suggest that Hdac3 serves as a critical regulator of craniofacial morphogenesis, in part by repressing core apoptotic pathways in cranial neural crest cells. Copyright © 2013 Elsevier Inc. All rights reserved.

A role for p21 (WAF1) in the cAMP-dependent differentiation of F9 teratocarcinoma cells into parietal endoderm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drdova, Blanka; Vachtenheim, Jiri

2005-03-10

Combined treatment of teratocarcinoma F9 cells with retinoic acid and dibutyryl-cAMP induces the differentiation into cells with a phenotype resembling parietal endoderm. We show that the levels of cyclin-dependent kinase inhibitor p21/WAF1/Cip1 (p21) protein and mRNA are dramatically elevated at the end of this differentiation, concomitantly with the appearance of p21 in the immunoprecipitated CDK2-cyclin E complex. The induction of differentiation markers could not be achieved by expression of ectopic p21 alone and still required treatment with differentiation agents. Clones of F9 cells transfected with sense or antisense p21 cDNA constructs revealed, upon differentiation, upregulated levels of mRNA for thrombomodulin,more » a parietal endoderm-specific marker, or increased fraction of cells in sub-G1 phase of the cell cycle, respectively. Consistent with this observation, whereas p21 was strictly nuclear in undifferentiated cells, a large proportion of differentiated cells had p21 localized also in the cytoplasm, a site associated with the antiapoptotic function of p21. Furthermore, p21 activated the thrombomodulin promoter in transient reporter assays and the p21 mutant defective in binding to cyclin E was equally efficient in activation. The promoter activity in differentiated cells was reduced by cotransfection of p21-specific siRNA or antisense cDNA. Coexpression of p21 increased the activity of the GAL-p300(1-1303) fusion protein on the GAL sites-containing TM promoter. This implies that p21 might act through a derepression of the p300 N-terminal-residing repression domain, thereby enhancing the p300 coactivator function. As differentiation of F9 cells into parietal endoderm-like cells requires the cAMP signaling, the results together suggest that the cyclin-dependent kinase inhibitor p21 may promote specifically this pathway in F9 cells.« less

Sequential activation of apical and basolateral contractility drives ascidian endoderm invagination

PubMed Central

Sherrard, Kristin; Robin, François; Lemaire, Patrick; Munro1, Edwin

2014-01-01

SUMMARY Background Epithelial invagination is a fundamental morphogenetic behavior that transforms a flat cell sheet into a pit or groove. Previous studies of invagination have focused on the role of actomyosin-dependent apical contraction; other mechanisms remain largely unexplored. Results We combined experimental and computational approaches to identify a two-step mechanism for endoderm invagination during ascidian gastrulation. During Step 1, which immediately precedes invagination, endoderm cells constrict their apices due to Rho/Rhokinase-dependent apical enrichment of 1P–myosin. Our data suggest that endoderm invagination itself occurs during Step 2, without further apical shrinkage, via a novel mechanism we call collared rounding: Rho/Rho-kinase-independent lateral enrichment of 1P–myosin drives apico-basal shortening, while Rho/Rho-kinase-dependent enrichment of 1P and 2P myosin in circumapical collars is required to prevent apical expansion and for deep invagination. Simulations show that boundary-specific tension values consistent with these distributions of active myosin can explain the cell shape changes observed during invagination both in normal embryos and in embryos treated with pharmacological inhibitors of either Rho-kinase or Myosin II ATPase. Indeed, we find that the balance of strong circumapical and basolateral tension is the only mechanism based on differential cortical tension that can explain ascidian endoderm invagination. Finally, simulations suggest that mesectoderm cells resist endoderm shape changes during both steps and we confirm this prediction experimentally. Conclusions Our findings suggest that early ascidian gastrulation is driven by the coordinated apposition of circumapical and lateral endoderm contraction, working against a resisting mesectoderm. We propose that similar mechanisms may operate during other invaginations. PMID:20691592

Role of the gut endoderm in relaying left-right patterning in mice.

PubMed

Viotti, Manuel; Niu, Lei; Shi, Song-Hai; Hadjantonakis, Anna-Katerina

2012-01-01

Establishment of left-right (LR) asymmetry occurs after gastrulation commences and utilizes a conserved cascade of events. In the mouse, LR symmetry is broken at a midline structure, the node, and involves signal relay to the lateral plate, where it results in asymmetric organ morphogenesis. How information transmits from the node to the distantly situated lateral plate remains unclear. Noting that embryos lacking Sox17 exhibit defects in both gut endoderm formation and LR patterning, we investigated a potential connection between these two processes. We observed an endoderm-specific absence of the critical gap junction component, Connexin43 (Cx43), in Sox17 mutants. Iontophoretic dye injection experiments revealed planar gap junction coupling across the gut endoderm in wild-type but not Sox17 mutant embryos. They also revealed uncoupling of left and right sides of the gut endoderm in an isolated domain of gap junction intercellular communication at the midline, which in principle could function as a barrier to communication between the left and right sides of the embryo. The role for gap junction communication in LR patterning was confirmed by pharmacological inhibition, which molecularly recapitulated the mutant phenotype. Collectively, our data demonstrate that Cx43-mediated communication across gap junctions within the gut endoderm serves as a mechanism for information relay between node and lateral plate in a process that is critical for the establishment of LR asymmetry in mice.

Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation.

PubMed Central

Trojan, J; Johnson, T R; Rudin, S D; Blossey, B K; Kelley, K M; Shevelev, A; Abdul-Karim, F W; Anthony, D D; Tykocinski, M L; Ilan, J

1994-01-01

Teratocarcinoma is a germ-line carcinoma giving rise to an embryoid tumor with structures derived from the three embryonic layers: mesoderm, endoderm, and ectoderm. Teratocarcinoma is widely used as an in vitro model system to study regulation of cell determination and differentiation during mammalian embryogenesis. Murine embryonic carcinoma (EC) PCC3 cells express insulin-like growth factor I(IGF-I) and its receptor, while all derivative tumor structures express IGF-I and IGF-II and their receptors. Therefore the system lends itself to dissect the role of these two growth factors during EC differentiation. With an episomal antisense strategy, we define a role for IGF-I in tumorigenicity and evasion of immune surveillance. Antisense IGF-I EC transfectants are shown to elicit a curative anti-tumor immune response with tumor regression at distal sites. In contrast, IGF-II is shown to drive determination and differentiation in EC cells. Since IGF-I and IGF-II bind to type I receptor and antisense sequence used for IGF-II cannot form duplex with endogenous IGF-I transcripts, it follows that this receptor is not involved in determination and differentiation. Images PMID:8016120

Identification of a novel aminergic-like G protein-coupled receptor in the cnidarian Renilla koellikeri.

PubMed

Bouchard, Christelle; Ribeiro, Paula; Dubé, François; Demers, Christian; Anctil, Michel

2004-10-27

Biogenic amines exert various physiological effects in cnidarians, but the receptors involved in these responses are not known. We have cloned a novel G protein-coupled receptor cDNA from an anthozoan, the sea pansy Renilla koellikeri, that shows homology to mammalian catecholamine receptors and, to a lesser extent, to peptidergic receptors. This putative receptor, named Ren2, has a DRC pattern that replaces the well-conserved DRY motif on the cytoplasmic side of the transmembrane III and lacks the cysteine residues usually found in the second extracellular loop and C-terminus tail. Both the second extracellular loop and the N-terminal tail were seen to be short (six and three amino acids, respectively). Northern blot analysis suggests that the receptor gene codes for two transcripts. Localization of these transcripts by in situ hybridization demonstrated abundant expression in the epithelium of the pharyngeal wall, the oral disk and tentacles as well as in the endodermal epithelium lining the gastrovascular cavities.

Conserved Genetic Pathways Controlling the Development of the Diffuse Endocrine System in Vertebrates and Drosophila

PubMed Central

Hartenstein, Volker; Takashima, Shigeo; Adams, Katrina

2014-01-01

The midgut epithelium is formed by absorptive enterocytes, secretory cells and endocrine cells. Each of these lineages is derived from the pluripotent progenitors that constitute the embryonic endoderm; the mature midgut retains pools of self-renewing stem cells that continue to produce all lineages. Recent findings in vertebrates and Drosophila shed light on the genetic mechanism that specifies the fate of the different lineages. A pivotal role is played by the Notch signaling pathway that, in a manner that appears to be very similar to the way in which Notch signaling selects neural progenitors within the neurectoderm, distinguishes the fate of secretory/endocrine cells and enterocytes. Proneural genes encoding bHLH transcription factors are expressed and required in prospective endocrine cells; activation of the Notch pathways restricts the number of these cells and promotes enterocyte development. In this review we compare the development of the intestinal endocrine cells in vertebrates and insects and summarize recent findings dealing with genetic pathways controlling this cell type. PMID:20005229

Puromycin-resistant lentiviral control shRNA vector, pLKO.1 induces unexpected cellular differentiation of P19 embryonic stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanungo, Jyotshna

RNA silencing is used as a common method for investigating loss-of-function effects of genes of interest. In mammalian cells, RNA interference (RNAi) or RNA silencing can be achieved by transient siRNA (small or short interfering RNA) transfection or by stable shRNA (short hairpin RNA) systems. Various vectors are used for efficient delivery of shRNA. Lentiviral vectors offer an efficient delivery system for stable and long-term expression of the shRNA in mammalian cells. The widely used lentiviral pLKO.1 plasmid vector is very popular in RNAi studies. A large RNAi database, a TRC (the RNAi Consortium) library, was established based on themore » pLKO.1-TRC plasmid vector. This plasmid (also called pLKO.1-puro) has a puromycin-resistant gene for selection in mammalian cells along with designs for generating lentiviral particles as well for RNA silencing. While using the pLKO.1-puro TRC control shRNA plasmid for transfection in murine P19 embryonic stem (ES) cells, it was unexpectedly discovered that this plasmid vector induced robust endodermal differentiation. Since P19 ES cells are pluripotent and respond to external stimuli that have the potential to alter the phenotype and thus its stemness, other cell types used in RNA silencing studies do not display the obvious effect and therefore, may affect experiments in subtle ways that would go undetected. This study for the first time provides evidence that raises concern and warrants extreme caution while using the pLKO.1-puro control shRNA vector because of its unexpected non-specific effects on cellular integrity. - Highlights: • In P19 ES cells the pLKO.1-puro lentiviral control shRNA vector induced endodermal differentiation. • P19 ES cells harboring the pCDNA3 plasmid vector retained their stem-ness as opposed to those harboring the pLKO.1-puro vector. • P19 ES cells can serve as a sensor to determine vector safety. • Extreme caution is warranted while using the widely used pLKO.1-puro lentiviral vector for experimental and therapeutic designs.« less

KDR (VEGFR2) identifies a conserved human and murine hepatic progenitor and instructs early liver development

PubMed Central

Goldman, Orit; Han, Songyan; Sourrisseau, Marion; Dziedzic, Noelle; Hamou, Wissam; Corneo, Barbara; D’Souza, Sunita; Sato, Thomas; Kotton, Darrell N.; Bissig, Karl-Dimiter; Kalir, Tamara; Jacobs, Adam; Evans, Todd; Evans, Matthew J.; Gouon-Evans, Valerie

2013-01-01

SUMMARY Understanding the fetal hepatic niche is essential for optimizing the generation of functional hepatocyte-like (hepatic) cells from human embryonic stem cells (hESCs). Here, we show that KDR (VEGFR2), previously assumed to be mostly restricted to mesodermal lineages, marks a hESC-derived hepatic progenitor. hESC-derived endoderm cells do not express KDR, but when cultured in media supporting hepatic differentiation, generate KDR+ hepatic progenitors and KDR- hepatic cells. KDR+ progenitors require active KDR signaling both to instruct their own differentiation into hepatic cells, and to support non-cell-autonomously the functional maturation of co-cultured KDR- hepatic cells. Analysis of human fetal livers suggests that similar progenitors are present in human livers. Lineage tracing in mice provides in vivo evidence of a KDR+ hepatic progenitor for fetal hepatoblasts and subsequently adult hepatocytes and cholangiocytes. Altogether, our findings reveal that KDR is a conserved marker for endoderm-derived hepatic progenitors, and a functional receptor instructing early liver development. PMID:23746980

The expression of the class 1 glucose transporter isoforms in human embryonic stem cells, and the potential use of GLUT2 as a marker for pancreatic progenitor enrichment.

PubMed

Segev, Hana; Fishman, Betina; Schulman, Rita; Itskovitz-Eldor, Joseph

2012-07-01

Even before the first appearance of the developing pancreas, glucose is the major substrate in the growing embryo. The transport of glucose across cell membranes is facilitated by a family of membranal glucose transporters (GLUT). We analyzed changes in expression of class 1 glucose transporters (GLUT1-4) during human embryonic stem cell (hESC) and human induced pluripotent stem cell (hiPSC) differentiation, from undifferentiated cells to 28-day-old embryoid bodies (EBs). We also examined the potential use of GLUT2 as a marker for differentiating pancreatic progenitor cells. Using quantitative real time polymerase chain reaction (qPCR), western blot, and immunofluorescence, we observed enhanced expression of GLUT1 and GLUT2 during differentiation, but only minor change in GLUT3 expression. GLUT4 expression was found to be very low both at the RNA and in the protein levels. Expression of the early pancreatic transcription factor, pancreatic duodenal homeobox gene 1 (PDX1), correlated with GLUT2 expression, suggesting the potential use of GLUT2 as a surface marker for tracking pancreatic precursor cells. After sorting EBs according to their membranal GLUT2 expression, GLUT2 and PDX1 expression were found elevated, as was expression of other endodermal markers such as PAX4, NGN3, CXCR4, and SOX17. This simple method may be used to differentiate embryonic stem cells and to isolate from them, using GLUT2 as a surface marker, an enriched pancreatic progenitor cell population in order to achieve insulin-producing cells. The sorted GLUT2 cells may potentially be used in the future as insulin-producing cells for beta cell therapies.

Evaluation of the Adult Goldfish Brain as a Model for the Study of Progenitor Cells

DTIC Science & Technology

2007-08-27

embryo [34]. ESCs are able to differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm, and they are...postnatal brain is their functional and anatomical destiny . Based on many reports investigating neurogenesis, the majority of newly produced cells...Homeodomain-bearing transcriptional factor. Expression is specific to early embryos and pluripotential stem cells. Key molecule involved in the

A C2H2-type zinc finger protein, SGR5, is involved in early events of gravitropism in Arabidopsis inflorescence stems.

PubMed

Morita, Miyo T; Sakaguchi, Keitaro; Kiyose, Shin-Ichiro; Taira, Kensuke; Kato, Takehide; Nakamura, Moritaka; Tasaka, Masao

2006-08-01

Plants can sense the direction of gravity and change the growth orientation of their organs. To elucidate the molecular mechanisms of gravity perception and the signal transduction of gravitropism, we have characterized a number of shoot gravitropism (sgr) mutants of Arabidopsis. The sgr5-1 mutant shows reduced gravitropism in the inflorescence stem but its root and hypocotyl have normal gravitropism. SGR5 encodes a zinc finger protein with a coiled-coil motif. The SGR5-GFP fusion protein is localized in the nucleus of Arabidopsis protoplasts, suggesting that SGR5 may act as a transcription factor. Analysis of GUS expression under the control of the SGR5 promoter revealed that SGR5 is mainly expressed in the endodermis, the gravity-sensing tissue in inflorescence stems. Furthermore, the observation that endodermis-specific expression of SGR5 using the SCR promoter in the sgr5-1 mutant restores shoot gravitropism indicates that it could function in the gravity-sensing endodermal cell layer. In contrast to other sgr mutants reported previously, almost all amyloplasts in the endodermal cells of the sgr5-1 mutant sedimented in the direction of gravity. Taken together, our results suggest that SGR5 may be involved in an early event in shoot gravitropism such as gravity perception and/or a signaling process subsequent to amyloplast sedimentation as a putative transcription factor in gravity-perceptive cells.

Retinol Dehydrogenase-10 Regulates Pancreas Organogenesis and Endocrine Cell Differentiation via Paracrine Retinoic Acid Signaling.

PubMed

Arregi, Igor; Climent, Maria; Iliev, Dobromir; Strasser, Jürgen; Gouignard, Nadège; Johansson, Jenny K; Singh, Tania; Mazur, Magdalena; Semb, Henrik; Artner, Isabella; Minichiello, Liliana; Pera, Edgar M

2016-12-01

Vitamin A-derived retinoic acid (RA) signals are critical for the development of several organs, including the pancreas. However, the tissue-specific control of RA synthesis in organ and cell lineage development has only poorly been addressed in vivo. Here, we show that retinol dehydrogenase-10 (Rdh10), a key enzyme in embryonic RA production, has important functions in pancreas organogenesis and endocrine cell differentiation. Rdh10 was expressed in the developing pancreas epithelium and surrounding mesenchyme. Rdh10 null mutant mouse embryos exhibited dorsal pancreas agenesis and a hypoplastic ventral pancreas with retarded tubulogenesis and branching. Conditional disruption of Rdh10 from the endoderm caused increased mortality, reduced body weight, and lowered blood glucose levels after birth. Endodermal Rdh10 deficiency led to a smaller dorsal pancreas with a reduced density of early glucagon + and insulin + cells. During the secondary transition, the reduction of Neurogenin3 + endocrine progenitors in the mutant dorsal pancreas accounted for fewer α- and β-cells. Changes in the expression of α- and β-cell-specific transcription factors indicated that Rdh10 might also participate in the terminal differentiation of endocrine cells. Together, our results highlight the importance of both mesenchymal and epithelial Rdh10 for pancreogenesis and the first wave of endocrine cell differentiation. We further propose a model in which the Rdh10-expressing exocrine tissue acts as an essential source of RA signals in the second wave of endocrine cell differentiation.

Characteristics of bovine inner cell mass-derived cell lines and their fate in chimeric conceptuses.

PubMed

Furusawa, Tadashi; Ohkoshi, Katsuhiro; Kimura, Koji; Matsuyama, Shuichi; Akagi, Satoshi; Kaneda, Masahiro; Ikeda, Mitsumi; Hosoe, Misa; Kizaki, Keiichiro; Tokunaga, Tomoyuki

2013-08-01

Bovine embryonic stem (ES) cells have the potential to provide significant benefits in a range of agricultural and biomedical applications. Here, we employed a combination of conventional methods using glycogen synthase kinase 3 and mitogen-activated protein kinase inhibitors to establish ES cell lines from in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) bovine embryos. Five male cell lines were established from IVF embryos, and two female and three male cell lines from SCNT blastocysts; we named these lines bovine ES cell-like cells (bESLCs). The lines exhibited dome-shaped colonies, stained positively for alkaline phosphatase, and expressed pluripotent stem cell markers such as POU5F1, SOX2, and SSEA-1. The expression levels of these markers, especially for NANOG, varied among the cell lines. A DNA methylation assay showed the POU5F1 promoter region was hypomethylated compared to fibroblast cells. An in vitro differentiation assay showed that endoderm and ectoderm marker genes, but not mesoderm markers, were upregulated in differentiating bESLCs. To examine bESLCs in later embryonic stages, we created 22 chimeric blastocysts with a male bESLC line carrying a GFP marker gene and transferred these to a recipient cow. Four chimeric embryos were subsequently retrieved on Day 13 and retransferred to two recipient cows. One living fetus was obtained at Day 62. GFP signals were not identified in fetal cells by fluorescence microscopy; however, genomic PCR analysis detected the GFP gene in major organs. Clusters of GFP-positive cells were observed in amniotic membranes, suggesting that bESLCs can be categorized as a novel type of ICM-derived cells that can potentially differentiate into epiblast and hypoblast lineages.

Conservation of Endo16 expression in sea urchins despite evolutionary divergence in both cis and trans-acting components of transcriptional regulation

NASA Technical Reports Server (NTRS)

Romano, Laura A.; Wray, Gregory A.

2003-01-01

Evolutionary changes in transcriptional regulation undoubtedly play an important role in creating morphological diversity. However, there is little information about the evolutionary dynamics of cis-regulatory sequences. This study examines the functional consequence of evolutionary changes in the Endo16 promoter of sea urchins. The Endo16 gene encodes a large extracellular protein that is expressed in the endoderm and may play a role in cell adhesion. Its promoter has been characterized in exceptional detail in the purple sea urchin, Strongylocentrotus purpuratus. We have characterized the structure and function of the Endo16 promoter from a second sea urchin species, Lytechinus variegatus. The Endo16 promoter sequences have evolved in a strongly mosaic manner since these species diverged approximately 35 million years ago: the most proximal region (module A) is conserved, but the remaining modules (B-G) are unalignable. Despite extensive divergence in promoter sequences, the pattern of Endo16 transcription is largely conserved during embryonic and larval development. Transient expression assays demonstrate that 2.2 kb of upstream sequence in either species is sufficient to drive GFP reporter expression that correctly mimics this pattern of Endo16 transcription. Reciprocal cross-species transient expression assays imply that changes have also evolved in the set of transcription factors that interact with the Endo16 promoter. Taken together, these results suggest that stabilizing selection on the transcriptional output may have operated to maintain a similar pattern of Endo16 expression in S. purpuratus and L. variegatus, despite dramatic divergence in promoter sequence and mechanisms of transcriptional regulation.

Isolation and characterization of EG-like cells from Chinese swamp buffalo (Bubalus bubalis).

PubMed

Huang, Ben; Xie, Ti-San; Shi, De-Shun; Li, Tong; Wang, Xiao-Li; Mo, Yi; Wang, Zhi-Qiang; Li, Meng-Mei

2007-10-01

There have been few studies done on the isolation and characterization of Chinese swamp buffalo embryonic germ cells (EG cells). Here, we first report on EG-like cells isolated from Chinese swamp buffalo fetuses. The results showed the cells grew in large, multilayered colonies, which were densely packed with an obvious border resembling mouse embryonic stem cells (ES cells) and EG cells. The buffalo EG-like cells expressed AP, SSEA-1, SSEA-3, SSEA-4 and OCT-4. By RT-PCR, we found that undifferentiated swamp buffalo EG-like cells expressed the OCT-4, NANOG, SOX2, FOXD3, GP130, STAT3, and HEB gene mRNA, but not Fgf4. When these cells were cultured for more than 2weeks without passage, they could differentiate into several types of cells including fibroblast-like, neuron-like, smooth muscle-like, and epithelial-like cells. Some cells formed simple embryoid bodies (EBs) and cystic EBs by suspension culture. By RT-PCR, we found cystic EBs expressed FOXD3, GP130, STAT3 and HEB gene mRNA, but not OCT-4, NANOG, and SOX2 gene mRNA, which could be detected in undifferentiated buffalo EG-like cells. At the same time, the expression of KERATIN-14 (Endoderm), GATA4, ACTA2 (Mesoderm) and TUBB3 (Ectoderm) gene mRNA were also detected in cystic EBs. The results suggested that these cells were capable of forming three germ layers in in vitro differentiation. The expression of OCT-4, NANOG and SOX2 might be essential for Chinese swamp buffalo EG-like cells in a pluripotent state. During the isolation and culture of Chinese swamp buffalo EG-like cells, we found the fetuses that were at 30-80days post-coitus were more efficient than others; and the mechanical method was better than trypsin digestion. The maximal passage of the mechanical method was eight, but the trypsin digestion was just three passages. So it seemed like that the buffalo EG-like cells were sensitive to trypsin. In summary, we were the first to isolate and characterize Chinese swamp buffalo EG-like cells that had morphology and characterization similar to those of established EG/EG-like cells in mouse and human.

Germ layer differentiation during early hindgut and cloaca formation in rabbit and pig embryos

PubMed Central

Hassoun, Romia; Schwartz, Peter; Rath, Detlef; Viebahn, Christoph; Männer, Jörg

2010-01-01

Relative to recent advances in understanding molecular requirements for endoderm differentiation, the dynamics of germ layer morphology and the topographical distribution of molecular factors involved in endoderm formation at the caudal pole of the embryonic disc are still poorly defined. To discover common principles of mammalian germ layer development, pig and rabbit embryos at late gastrulation and early neurulation stages were analysed as species with a human-like embryonic disc morphology, using correlative light and electron microscopy. Close intercellular contact but no direct structural evidence of endoderm formation such as mesenchymal–epithelial transition between posterior primitive streak mesoderm and the emerging posterior endoderm were found. However, a two-step process closely related to posterior germ layer differentiation emerged for the formation of the cloacal membrane: (i) a continuous mesoderm layer and numerous patches of electron-dense flocculent extracellular matrix mark the prospective region of cloacal membrane formation; and (ii) mesoderm cells and all extracellular matrix including the basement membrane are lost locally and close intercellular contact between the endoderm and ectoderm is established. The latter process involves single cells at first and then gradually spreads to form a longitudinally oriented seam-like cloacal membrane. These gradual changes were found from gastrulation to early somite stages in the pig, whereas they were found from early somite to mid-somite stages in the rabbit; in both species cloacal membrane formation is complete prior to secondary neurulation. The results highlight the structural requirements for endoderm formation during development of the hindgut and suggest new mechanisms for the pathogenesis of common urogenital and anorectal malformations. PMID:20874819

Transcriptional Ontogeny of the Developing Liver

EPA Science Inventory

During embryogenesis the liver is derived from endodermal cells lining the digestive tract. These endodermal progenitor cells contribute to forming the parenchyma of a number of organs including the liver and pancreas. Early in organogenesis the fetal liver is populated by hemato...

Generation of Distal Airway Epithelium from Multipotent Human Foregut Stem Cells.

PubMed

Hannan, Nicholas R F; Sampaziotis, Fotios; Segeritz, Charis-Patricia; Hanley, Neil A; Vallier, Ludovic

2015-07-15

Collectively, lung diseases are one of the largest causes of premature death worldwide and represent a major focus in the field of regenerative medicine. Despite significant progress, only few stem cell platforms are currently available for cell-based therapy, disease modeling, and drug screening in the context of pulmonary disorders. Human foregut stem cells (hFSCs) represent an advantageous progenitor cell type that can be used to amplify large quantities of cells for regenerative medicine applications and can be derived from any human pluripotent stem cell line. Here, we further demonstrate the application of hFSCs by generating a near homogeneous population of early pulmonary endoderm cells coexpressing NKX2.1 and FOXP2. These progenitors are then able to form cells that are representative of distal airway epithelium that express NKX2.1, GATA6, and cystic fibrosis transmembrane conductance regulator (CFTR) and secrete SFTPC. This culture system can be applied to hFSCs carrying the CFTR mutation Δf508, enabling the development of an in vitro model for cystic fibrosis. This platform is compatible with drug screening and functional validations of small molecules, which can reverse the phenotype associated with CFTR mutation. This is the first demonstration that multipotent endoderm stem cells can differentiate not only into both liver and pancreatic cells but also into lung endoderm. Furthermore, our study establishes a new approach for the generation of functional lung cells that can be used for disease modeling as well as for drug screening and the study of lung development.

Analyses of pancreas development by generation of gfp transgenic zebrafish using an exocrine pancreas-specific elastaseA gene promoter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan Haiyan; Korzh, Svitlana; Li Zhen

2006-05-15

In contrast to what we know on development of endocrine pancreas, the formation of exocrine pancreas remains poorly understood. To create an animal model that allows observation of exocrine cell differentiation, proliferation, and morphogenesis in living animals, we used the zebrafish elastaseA (elaA) regulatory sequence to develop transgenic zebrafish that display highly specific exocrine pancreas expression of GFP in both larvae and adult. By following GFP expression, we found that the pancreas in early development was a relatively compact organ and later extended posterior along the intestine. By transferring the elaA:gfp transgene into slow muscle omitted mutant that is deficientmore » in receiving Hedgehog signals, we further showed that Hedgehog signaling is required for exocrine morphogenesis but not for cell differentiation. We also applied the morpholino knockdown and toxin-mediated cell ablation approaches to this transgenic line. We showed that the development of exocrine pancreas is Islet-1 dependent. Injection of the diphtheria toxin A (DTA) construct under the elastaseA promoter resulted in selective ablation of exocrine cells while the endocrine cells and other endodermal derivatives (liver and intestine) were not affected. Thus, our works demonstrated the new transgenic line provided a useful experimental tool in analyzing exocrine pancreas development.« less

Derivation and characterisation of the human embryonic stem cell lines, NOTT1 and NOTT2.

PubMed

Priddle, Helen; Allegrucci, Cinzia; Burridge, Paul; Munoz, Maria; Smith, Nigel M; Devlin, Lyndsey; Sjoblom, Cecilia; Chamberlain, Sarah; Watson, Sue; Young, Lorraine E; Denning, Chris

2010-04-01

The ability to maintain human embryonic stem cells (hESCs) during long-term culture and yet induce differentiation to multiple lineages potentially provides a novel approach to address various biomedical problems. Here, we describe derivation of hESC lines, NOTT1 and NOTT2, from human blastocysts graded as 3BC and 3CB, respectively. Both lines were successfully maintained as colonies by mechanical passaging on mouse embryonic feeder cells or as monolayers by trypsin-passaging in feeder-free conditions on Matrigel. Undifferentiated cells retained expression of pluripotency markers (OCT4, NANOG, SSEA-4, TRA-1-60 and TRA-1-81), a stable karyotype during long-term culture and could be transfected efficiently with plasmid DNA and short interfering RNA. Differentiation via formation of embryoid bodies resulted in expression of genes associated with early germ layers and terminal lineage specification. The electrophysiology of spontaneously beating NOTT1-derived cardiomyocytes was recorded and these cells were shown to be pharmacologically responsive. Histological examination of teratomas formed by in vivo differentiation of both lines in severe immunocompromised mice showed complex structures including cartilage or smooth muscle (mesoderm), luminal epithelium (endoderm) and neuroectoderm (ectoderm). These observations show that NOTT1 and NOTT2 display the accepted characteristics of hESC pluripotency.

Isolation and characterization of Vasa in the frog Rana rugosa.

PubMed

Saotome, Kazuhiro; Hayashi, Kota; Adachi, Noritaka; Nakamura, Yoriko; Nakamura, Masahisa

2010-08-01

We cloned a cDNA encoding Vasa, a member of the DEAD (Asp-Glu-Ala-Asp) family of proteins, from the ovary of the frog Rana rugosa. Comparative alignment of amino acid sequences with known Vasa from several species of vertebrate showed that the R. rugosa orthologue shares eight conserved regions with Vasa from other vertebrates. Vasa gene expression was restricted to the testis and ovary among ten different tissues examined. Vasa expression showed no sexual dimorphism during sex determination in R. rugosa, but became higher in the ovary thereafter. By Western blot analysis, a single Vasa band with a molecular weight of 80.9 kDa was detected. The same antibody immunohistochemically detected Vasa in a few cells in the embryonic endoderm at stage 15; the beginning of closure of neural folds, and in the cytoplasm of spermatogonia in the testis, and oocytes in the ovary of tadpoles at stage XX; marked by one or both forelegs protruded. Together, these results suggest that Vasa is a highly specific marker of germ cells and hence useful for studies of germ cell specification and function in amphibians as it already is in other species of both invertebrates and vertebrates such as Drosophila and zebrafish. (c) 2010 Wiley-Liss, Inc.

Wnt-dependent epithelial transitions drive pharyngeal pouch formation

PubMed Central

Choe, Chong Pyo; Collazo, Andres; Trinh, Le A.; Pan, Luyuan; Moens, Cecilia B.; Crump, J. Gage

2013-01-01

SUMMARY The pharyngeal pouches, which form by budding of the foregut endoderm, are essential for segmentation of the vertebrate face. To date, the cellular mechanism and segmental nature of such budding have remained elusive. Here, we find that Wnt11r and Wnt4a from the head mesoderm and ectoderm, respectively, play distinct roles in the segmental formation of pouches in zebrafish. Time-lapse microscopy, combined with mutant and tissue-specific transgenic experiments, reveal requirements of Wnt signaling in two phases of endodermal epithelial transitions. Initially, Wnt11r and Rac1 destabilize the endodermal epithelium to promote the lateral movement of pouch-forming cells. Next, Wnt4a and Cdc42 signaling induce the rearrangement of maturing pouch cells into bilayers through junctional localization of the Alcama immunoglobulin-domain protein, which functions to restabilize adherens junctions. We propose that this dynamic control of epithelial morphology by Wnt signaling may be a common theme for the budding of organ anlagen from the endoderm. PMID:23375584

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish.

PubMed

Lovely, C Ben; Swartz, Mary E; McCarthy, Neil; Norrie, Jacqueline L; Eberhart, Johann K

2016-06-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. © 2016. Published by The Company of Biologists Ltd.

Ingression-type cell migration drives vegetal endoderm internalisation in the Xenopus gastrula

PubMed Central

Wen, Jason WH

2017-01-01

During amphibian gastrulation, presumptive endoderm is internalised as part of vegetal rotation, a large-scale movement that encompasses the whole vegetal half of the embryo. It has been considered a gastrulation process unique to amphibians, but we show that at the cell level, endoderm internalisation exhibits characteristics reminiscent of bottle cell formation and ingression, known mechanisms of germ layer internalisation. During ingression proper, cells leave a single-layered epithelium. In vegetal rotation, the process occurs in a multilayered cell mass; we refer to it as ingression-type cell migration. Endoderm cells move by amoeboid shape changes, but in contrast to other instances of amoeboid migration, trailing edge retraction involves ephrinB1-dependent macropinocytosis and trans-endocytosis. Moreover, although cells are separated by wide gaps, they are connected by filiform protrusions, and their migration depends on C-cadherin and the matrix protein fibronectin. Cells move in the same direction but at different velocities, to rearrange by differential migration. PMID:28826499

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish

PubMed Central

Swartz, Mary E.; McCarthy, Neil; Norrie, Jacqueline L.; Eberhart, Johann K.

2016-01-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. PMID:27122171

Purification of adult hepatic progenitor cells using green fluorescent protein (GFP)-transgenic mice and fluorescence-activated cell sorting.

PubMed

Fujikawa, Takahisa; Hirose, Tetsuro; Fujii, Hideaki; Oe, Shoshiro; Yasuchika, Kentaro; Azuma, Hisaya; Yamaoka, Yoshio

2003-08-01

Recent advances in stem cell research have revealed that hepatic stem/progenitor cells may play an important role in liver development and regeneration. However, a lack of detectable definitive markers in viable cells has hindered their primary culture from adult livers. Enzymatically dissociated liver cells from green fluorescent protein (GFP)-transgenic mice, which express GFP highly in liver endodermal cells, were sorted by GFP expression using a fluorescence-activated cell sorter. Sorted cells were characterized, and also low-density cultured for extended periods to determine their proliferation and clonal differentiation capacities. When CD45(-)TER119(-) side-scatter(low) GFP(high) cells were sorted, alpha-fetoprotein-positive immature endoderm-characterized cells, having high growth potential, were present in this population. Clonal analysis and electron microscopic evaluation revealed that each single cell of this population could differentiate not only into hepatocytes, but also into biliary epithelial cells, showing their bilineage differentiation activity. When surface markers were analyzed, they were positive for Integrin-alpha6 and -beta1, but negative for c-Kit and Thy1.1. Combination of GFP-transgenic mice and fluorescence-activated cell sorting enabled purification of hepatic progenitor cells from adult mouse liver. Further analysis of this population may lead to purification of their human correspondence that would be an ideal cell-source candidate for regenerative medicine.

Bypassing Iron Storage in Endodermal Vacuoles Rescues the Iron Mobilization Defect in the natural resistance associated-macrophage protein3natural resistance associated-macrophage protein4 Double Mutant1[OPEN

PubMed Central

Mary, Viviane; Schnell Ramos, Magali; Gillet, Cynthia; Socha, Amanda L.; Giraudat, Jérôme; Agorio, Astrid; Merlot, Sylvain; Clairet, Colin; Kim, Sun A.; Punshon, Tracy; Guerinot, Mary Lou; Thomine, Sébastien

2015-01-01

To improve seed iron (Fe) content and bioavailability, it is crucial to decipher the mechanisms that control Fe storage during seed development. In Arabidopsis (Arabidopsis thaliana) seeds, most Fe is concentrated in insoluble precipitates, with phytate in the vacuoles of cells surrounding the vasculature of the embryo. NATURAL RESISTANCE ASSOCIATED-MACROPHAGE PROTEIN3 (AtNRAMP3) and AtNRAMP4 function redundantly in Fe retrieval from vacuoles during germination. When germinated under Fe-deficient conditions, development of the nramp3nramp4 double mutant is arrested as a consequence of impaired Fe mobilization. To identify novel genes involved in seed Fe homeostasis, we screened an ethyl methanesulfonate-mutagenized population of nramp3nramp4 seedlings for mutations suppressing their phenotypes on low Fe. Here, we report that, among the suppressors, two independent mutations in the VACUOLAR IRON TRANSPORTER1 (AtVIT1) gene caused the suppressor phenotype. The AtVIT1 transporter is involved in Fe influx into vacuoles of endodermal and bundle sheath cells. This result establishes a functional link between Fe loading in vacuoles by AtVIT1 and its remobilization by AtNRAMP3 and AtNRAMP4. Moreover, analysis of subcellular Fe localization indicates that simultaneous disruption of AtVIT1, AtNRAMP3, and AtNRAMP4 limits Fe accumulation in vacuolar globoids. PMID:26232490

The Role of H1 Linker Histone Subtypes in Preserving the Fidelity of Elaboration of Mesendodermal and Neuroectodermal Lineages during Embryonic Development

PubMed Central

Nguyen, Giang D.; Gokhan, Solen; Molero, Aldrin E.; Yang, Seung-Min; Kim, Byung-Ju; Skoultchi, Arthur I.; Mehler, Mark F.

2014-01-01

H1 linker histone proteins are essential for the structural and functional integrity of chromatin and for the fidelity of additional epigenetic modifications. Deletion of H1c, H1d and H1e in mice leads to embryonic lethality by mid-gestation with a broad spectrum of developmental alterations. To elucidate the cellular and molecular mechanisms underlying H1 linker histone developmental functions, we analyzed embryonic stem cells (ESCs) depleted of H1c, H1d and H1e subtypes (H1-KO ESCs) by utilizing established ESC differentiation paradigms. Our study revealed that although H1-KO ESCs continued to express core pluripotency genes and the embryonic stem cell markers, alkaline phosphatase and SSEA1, they exhibited enhanced cell death during embryoid body formation and during specification of mesendoderm and neuroectoderm. In addition, we demonstrated deregulation in the developmental programs of cardiomyocyte, hepatic and pancreatic lineage elaboration. Moreover, ectopic neurogenesis and cardiomyogenesis occurred during endoderm-derived pancreatic but not hepatic differentiation. Furthermore, neural differentiation paradigms revealed selective impairments in the specification and maturation of glutamatergic and dopaminergic neurons with accelerated maturation of glial lineages. These impairments were associated with deregulation in the expression profiles of pro-neural genes in dorsal and ventral forebrain-derived neural stem cell species. Taken together, these experimental observations suggest that H1 linker histone proteins are critical for the specification, maturation and fidelity of organ-specific cellular lineages derived from the three cardinal germ layers. PMID:24802750

The gravity-induced re-localization of auxin efflux carrier CsPIN1 in cucumber seedlings: spaceflight experiments for immunohistochemical microscopy.

PubMed

Yamazaki, Chiaki; Fujii, Nobuharu; Miyazawa, Yutaka; Kamada, Motoshi; Kasahara, Haruo; Osada, Ikuko; Shimazu, Toru; Fusejima, Yasuo; Higashibata, Akira; Yamazaki, Takashi; Ishioka, Noriaki; Takahashi, Hideyuki

2016-01-01

Reorientation of cucumber seedlings induces re-localization of CsPIN1 auxin efflux carriers in endodermal cells of the transition zone between hypocotyl and roots. This study examined whether the re-localization of CsPIN1 was due to the graviresponse. Immunohistochemical analysis indicated that, when cucumber seedlings were grown entirely under microgravity conditions in space, CsPIN1 in endodermal cells was mainly localized to the cell side parallel to the minor axis of the elliptic cross-section of the transition zone. However, when cucumber seeds were germinated in microgravity for 24 h and then exposed to 1 g centrifugation in a direction crosswise to the seedling axis for 2 h in space, CsPIN1 was re-localized to the bottom of endodermal cells of the transition zone. These results reveal that the localization of CsPIN1 in endodermal cells changes in response to gravity. Furthermore, our results suggest that the endodermal cell layer becomes a canal by which auxin is laterally transported from the upper to the lower flank in response to gravity. The graviresponse-regulated re-localization of CsPIN1 could be responsible for the decrease in auxin level, and thus for the suppression of peg formation, on the upper side of the transition zone in horizontally placed seedlings of cucumber.

The gravity-induced re-localization of auxin efflux carrier CsPIN1 in cucumber seedlings: spaceflight experiments for immunohistochemical microscopy

PubMed Central

Yamazaki, Chiaki; Fujii, Nobuharu; Miyazawa, Yutaka; Kamada, Motoshi; Kasahara, Haruo; Osada, Ikuko; Shimazu, Toru; Fusejima, Yasuo; Higashibata, Akira; Yamazaki, Takashi; Ishioka, Noriaki; Takahashi, Hideyuki

2016-01-01

Reorientation of cucumber seedlings induces re-localization of CsPIN1 auxin efflux carriers in endodermal cells of the transition zone between hypocotyl and roots. This study examined whether the re-localization of CsPIN1 was due to the graviresponse. Immunohistochemical analysis indicated that, when cucumber seedlings were grown entirely under microgravity conditions in space, CsPIN1 in endodermal cells was mainly localized to the cell side parallel to the minor axis of the elliptic cross-section of the transition zone. However, when cucumber seeds were germinated in microgravity for 24 h and then exposed to 1g centrifugation in a direction crosswise to the seedling axis for 2 h in space, CsPIN1 was re-localized to the bottom of endodermal cells of the transition zone. These results reveal that the localization of CsPIN1 in endodermal cells changes in response to gravity. Furthermore, our results suggest that the endodermal cell layer becomes a canal by which auxin is laterally transported from the upper to the lower flank in response to gravity. The graviresponse-regulated re-localization of CsPIN1 could be responsible for the decrease in auxin level, and thus for the suppression of peg formation, on the upper side of the transition zone in horizontally placed seedlings of cucumber. PMID:28725738

A Phylogenetic Strategy Based on a Legume-Specific Whole Genome Duplication Yields Symbiotic Cytokinin Type-A Response Regulators1[C][W][OA

PubMed Central

Op den Camp, Rik H.M.; De Mita, Stéphane; Lillo, Alessandra; Cao, Qingqin; Limpens, Erik; Bisseling, Ton; Geurts, René

2011-01-01

Legumes host their Rhizobium spp. symbiont in novel root organs called nodules. Nodules originate from differentiated root cortical cells that dedifferentiate and subsequently form nodule primordia, a process controlled by cytokinin. A whole-genome duplication has occurred at the root of the legume Papilionoideae subfamily. We hypothesize that gene pairs originating from this duplication event and are conserved in distinct Papilionoideae lineages have evolved symbiotic functions. A phylogenetic strategy was applied to search for such gene pairs to identify novel regulators of nodulation, using the cytokinin phosphorelay pathway as a test case. In this way, two paralogous type-A cytokinin response regulators were identified that are involved in root nodule symbiosis. Response Regulator9 (MtRR9) and MtRR11 in medicago (Medicago truncatula) and an ortholog in lotus (Lotus japonicus) are rapidly induced upon Rhizobium spp. Nod factor signaling. Constitutive expression of MtRR9 results in arrested primordia that have emerged from cortical, endodermal, and pericycle cells. In legumes, lateral root primordia are not exclusively formed from pericycle cells but also require the involvement of the root cortical cell layer. Therefore, the MtRR9-induced foci of cell divisions show a strong resemblance to lateral root primordia, suggesting an ancestral function of MtRR9 in this process. Together, these findings provide a proof of principle for the applied phylogenetic strategy to identify genes with a symbiotic function in legumes. PMID:22034625

Fgfr1 regulates patterning of the pharyngeal region

PubMed Central

Trokovic, Nina; Trokovic, Ras; Mai, Petra; Partanen, Juha

2003-01-01

Development of the pharyngeal region depends on the interaction and integration of different cell populations, including surface ectoderm, foregut endoderm, paraxial mesoderm, and neural crest. Mice homozygous for a hypomorphic allele of Fgfr1 have craniofacial defects, some of which appeared to result from a failure in the early development of the second branchial arch. A stream of neural crest cells was found to originate from the rhombomere 4 region and migrate toward the second branchial arch in the mutants. Neural crest cells mostly failed to enter the second arch, however, but accumulated in a region proximal to it. Both rescue of the hypomorphic Fgfr1 allele and inactivation of a conditional Fgfr1 allele specifically in neural crest cells indicated that Fgfr1 regulates the entry of neural crest cells into the second branchial arch non-cell-autonomously. Gene expression in the pharyngeal ectoderm overlying the developing second branchial arch was affected in the hypomorphic Fgfr1 mutants at a stage prior to neural crest entry. Our results indicate that Fgfr1 patterns the pharyngeal region to create a permissive environment for neural crest cell migration. PMID:12514106

Conserved genetic pathways controlling the development of the diffuse endocrine system in vertebrates and Drosophila.

PubMed

Hartenstein, Volker; Takashima, Shigeo; Adams, Katrina L

2010-05-01

The midgut epithelium is formed by absorptive enterocytes, secretory cells and endocrine cells. Each of these lineages is derived from the pluripotent progenitors that constitute the embryonic endoderm; the mature midgut retains pools of self-renewing stem cells that continue to produce all lineages. Recent findings in vertebrates and Drosophila shed light on the genetic mechanism that specifies the fate of the different lineages. A pivotal role is played by the Notch signaling pathway that, in a manner that appears to be very similar to the way in which Notch signaling selects neural progenitors within the neurectoderm, distinguishes the fate of secretory/endocrine cells and enterocytes. Proneural genes encoding bHLH transcription factors are expressed and required in prospective endocrine cells; activation of the Notch pathways restricts the number of these cells and promotes enterocyte development. In this review we compare the development of the intestinal endocrine cells in vertebrates and insects and summarize recent findings dealing with genetic pathways controlling this cell type. Copyright 2009. Published by Elsevier Inc.

MYB36 regulates the transition from proliferation to differentiation in the Arabidopsis root

PubMed Central

Liberman, Louisa M.; Sparks, Erin E.; Moreno-Risueno, Miguel A.; Petricka, Jalean J.; Benfey, Philip N.

2015-01-01

Stem cells are defined by their ability to self-renew and produce daughter cells that proliferate and mature. These maturing cells transition from a proliferative state to a terminal state through the process of differentiation. In the Arabidopsis thaliana root the transcription factors SCARECROW and SHORTROOT regulate specification of the bipotent stem cell that gives rise to cortical and endodermal progenitors. Subsequent progenitor proliferation and differentiation generate mature endodermis, marked by the Casparian strip, a cell-wall modification that prevents ion diffusion into and out of the vasculature. We identified a transcription factor, MYB DOMAIN PROTEIN 36 (MYB36), that regulates the transition from proliferation to differentiation in the endodermis. We show that SCARECROW directly activates MYB36 expression, and that MYB36 likely acts in a feed-forward loop to regulate essential Casparian strip formation genes. We show that myb36 mutants have delayed and defective barrier formation as well as extra divisions in the meristem. Our results demonstrate that MYB36 is a critical positive regulator of differentiation and negative regulator of cell proliferation. PMID:26371322

A provisional regulatory gene network for specification of endomesoderm in the sea urchin embryo

NASA Technical Reports Server (NTRS)

Davidson, Eric H.; Rast, Jonathan P.; Oliveri, Paola; Ransick, Andrew; Calestani, Cristina; Yuh, Chiou-Hwa; Minokawa, Takuya; Amore, Gabriele; Hinman, Veronica; Arenas-Mena, Cesar;

The formation of endoderm-derived taste sensory organs requires a Pax9-dependent expansion of embryonic taste bud progenitor cells.

PubMed

Kist, Ralf; Watson, Michelle; Crosier, Moira; Robinson, Max; Fuchs, Jennifer; Reichelt, Julia; Peters, Heiko

2014-10-01

In mammals, taste buds develop in different regions of the oral cavity. Small epithelial protrusions form fungiform papillae on the ectoderm-derived dorsum of the tongue and contain one or few taste buds, while taste buds in the soft palate develop without distinct papilla structures. In contrast, the endoderm-derived circumvallate and foliate papillae located at the back of the tongue contain a large number of taste buds. These taste buds cluster in deep epithelial trenches, which are generated by intercalating a period of epithelial growth between initial placode formation and conversion of epithelial cells into sensory cells. How epithelial trench formation is genetically regulated during development is largely unknown. Here we show that Pax9 acts upstream of Pax1 and Sox9 in the expanding taste progenitor field of the mouse circumvallate papilla. While a reduced number of taste buds develop in a growth-retarded circumvallate papilla of Pax1 mutant mice, its development arrests completely in Pax9-deficient mice. In addition, the Pax9 mutant circumvallate papilla trenches lack expression of K8 and Prox1 in the taste bud progenitor cells, and gradually differentiate into an epidermal-like epithelium. We also demonstrate that taste placodes of the soft palate develop through a Pax9-dependent induction. Unexpectedly, Pax9 is dispensable for patterning, morphogenesis and maintenance of taste buds that develop in ectoderm-derived fungiform papillae. Collectively, our data reveal an endoderm-specific developmental program for the formation of taste buds and their associated papilla structures. In this pathway, Pax9 is essential to generate a pool of taste bud progenitors and to maintain their competence towards prosensory cell fate induction.

Identification of Annexin A4 as a hepatopancreas factor involved in liver cell survival

PubMed Central

Zhang, Danhua; Golubkov, Vladislav S.; Han, Wenlong; Correa, Ricardo G.; Zhou, Ying; Lee, Sunyoung; Strongin, Alex Y.; Dong, P. Duc Si

2014-01-01

To gain insight into liver and pancreas development, we investigated the target of 2F11, a monoclonal antibody of unknown antigen, widely used in zebrafish studies for labeling hepatopancreatic ducts. Utilizing mass spectrometry and in vivo assays, we determined the molecular target of 2F11 to be Annexin A4 (Anxa4), a calcium binding protein. We further found that in both zebrafish and mouse endoderm, Anxa4 is broadly expressed in the developing liver and pancreas, and later becomes more restricted to the hepatopancreatic ducts and pancreatic islets, including the insulin producing β-cells. Although Anxa4 is a known target of several monogenic diabetes genes and its elevated expression is associated with chemoresistance in malignancy, its in vivo role is largely unexplored. Knockdown of Anxa4 in zebrafish leads to elevated expression of caspase 8 and Δ113p53, and liver bud specific activation of Caspase 3 and apoptosis. Mosaic knockdown reveal that Anxa4 is required cell-autonomously in the liver bud for cell survival. This finding is further corroborated with mosaic anxa4 knockout studies using the CRISPR/Cas9 system. Collectively, we identify Anxa4 as a new, evolutionarily conserved hepatopancreatic factor that is required in zebrafish for liver progenitor viability, through inhibition of the extrinsic apoptotic pathway. A role for Anxa4 in cell survival may have implications for the mechanism of diabetic β-cell apoptosis and cancer cell chemoresistance. PMID:25176043

The evolutionary duplication and probable demise of an endodermal GATA factor in Caenorhabditis elegans.

PubMed

Fukushige, Tetsunari; Goszczynski, Barbara; Tian, Helen; McGhee, James D

2003-10-01

We describe the elt-4 gene from the nematode Caenorhabditis elegans. elt-4 is predicted to encode a very small (72 residues, 8.1 kD) GATA-type zinc finger transcription factor. The elt-4 gene is located approximately 5 kb upstream of the C. elegans elt-2 gene, which also encodes a GATA-type transcription factor; the zinc finger DNA-binding domains are highly conserved (24/25 residues) between the two proteins. The elt-2 gene is expressed only in the intestine and is essential for normal intestinal development. This article explores whether elt-4 also has a role in intestinal development. Reporter fusions to the elt-4 promoter or reporter insertions into the elt-4 coding regions show that elt-4 is indeed expressed in the intestine, beginning at the 1.5-fold stage of embryogenesis and continuing into adulthood. elt-4 reporter fusions are also expressed in nine cells of the posterior pharynx. Ectopic expression of elt-4 cDNA within the embryo does not cause detectable ectopic expression of biochemical markers of gut differentiation; furthermore, ectopic elt-4 expression neither inhibits nor enhances the ectopic marker expression caused by ectopic elt-2 expression. A deletion allele of elt-4 was isolated but no obvious phenotype could be detected, either in the gut or elsewhere; brood sizes, hatching efficiencies, and growth rates were indistinguishable from wild type. We found no evidence that elt-4 provided backup functions for elt-2. We used microarray analysis to search for genes that might be differentially expressed between L1 larvae of the elt-4 deletion strain and wild-type worms. Paired hybridizations were repeated seven times, allowing us to conclude, with some confidence, that no candidate target transcript could be identified as significantly up- or downregulated by loss of elt-4 function. In vitro binding experiments could not detect specific binding of ELT-4 protein to candidate binding sites (double-stranded oligonucleotides containing single or multiple WGATAR sequences); ELT-4 protein neither enhanced nor inhibited the strong sequence-specific binding of the ELT-2 protein. Whereas ELT-2 protein is a strong transcriptional activator in yeast, ELT-4 protein has no such activity under similar conditions, nor does it influence the transcriptional activity of coexpressed ELT-2 protein. Although an elt-2 homolog was easily identified in the genomic sequence of the related nematode C. briggsae, no elt-4 homolog could be identified. Analysis of the changes in silent third codon positions within the DNA-binding domains indicates that elt-4 arose as a duplication of elt-2, some 25-55 MYA. Thus, elt-4 has survived far longer than the average duplicated gene in C. elegans, even though no obvious biological function could be detected. elt-4 provides an interesting example of a tandemly duplicated gene that may originally have been the same size as elt-2 but has gradually been whittled down to its present size of little more than a zinc finger. Although elt-4 must confer (or must have conferred) some selective advantage to C. elegans, we suggest that its ultimate evolutionary fate will be disappearance from the C. elegans genome.

Inhibition of mitogen-activated protein kinase kinase, DNA methyltransferase, and transforming growth factor-β promotes differentiation of human induced pluripotent stem cells into enterocytes.

PubMed

Kodama, Nao; Iwao, Takahiro; Kabeya, Tomoki; Horikawa, Takashi; Niwa, Takuro; Kondo, Yuki; Nakamura, Katsunori; Matsunaga, Tamihide

2016-06-01

We previously reported that small-molecule compounds were effective in generating pharmacokinetically functional enterocytes from human induced pluripotent stem (iPS) cells. In this study, to determine whether the compounds promote the differentiation of human iPS cells into enterocytes, we investigated the effects of a combination of mitogen-activated protein kinase kinase (MEK), DNA methyltransferase (DNMT), and transforming growth factor (TGF)-β inhibitors on intestinal differentiation. Human iPS cells cultured on feeder cells were differentiated into endodermal cells by activin A. These endodermal-like cells were then differentiated into intestinal stem cells by fibroblast growth factor 2. Finally, the cells were differentiated into enterocyte cells by epidermal growth factor and small-molecule compounds. After differentiation, mRNA expression levels and drug-metabolizing enzyme activities were measured. The mRNA expression levels of the enterocyte marker sucrase-isomaltase and the major drug-metabolizing enzyme cytochrome P450 (CYP) 3A4 were increased by a combination of MEK, DNMT, and TGF-β inhibitors. The mRNA expression of CYP3A4 was markedly induced by 1α,25-dihydroxyvitamin D3. Metabolic activities of CYP1A1/2, CYP2B6, CYP2C9, CYP2C19, CYP3A4/5, UDP-glucuronosyltransferase, and sulfotransferase were also observed in the differentiated cells. In conclusion, MEK, DNMT, and TGF-β inhibitors can be used to promote the differentiation of human iPS cells into pharmacokinetically functional enterocytes. Copyright © 2016 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

Biochemical and morphological effects of hypoxic environment on human embryonic stem cells in long-term culture and differentiating embryoid bodies.

PubMed

Lim, Hee-Joung; Han, Jiyou; Woo, Dong-Hun; Kim, Sung-Eun; Kim, Suel-Kee; Kang, Hee-Gyoo; Kim, Jong-Hoon

2011-02-01

The mammalian reproductive tract is known to contain 1.5-5.3% oxygen (O(2)), but human embryonic stem cells (hESCs) derived from preimplantation embryos are typically cultured under 21% O(2) tension. The aim of this study was to investigate the effects of O(2) tension on the long-term culture of hESCs and on cell-fate determination during early differentiation. hESCs and embryoid bodies (EBs) were grown under different O(2) tensions (3, 12, and 21% O(2)). The expression of markers associated with pluripotency, embryonic germ layers, and hypoxia was analyzed using RTPCR, immunostaining, and Western blotting. Proliferation, apoptosis, and chromosomal aberrations were examined using BrdU incorporation, caspase-3 immunostaining, and karyotype analysis, respectively. Structural and morphological changes of EBs under different O(2) tensions were comparatively examined using azan- and hematoxylineosin staining, and scanning and transmission electron microscopy. Mild hypoxia (12% O(2)) increased the number of cells expressing Oct4/Nanog and reduced BrdU incorporation and aneuploidy. The percentage of cells positive for active caspase-3, which was high during normoxia (21% O(2)), gradually decreased when hESCs were continuously cultured under mild hypoxia. EBs subjected to hypoxia (3% O(2)) exhibited well-differentiated microvilli on their surface, secreted high levels of collagen, and showed enhanced differentiation into primitive endoderm. These changes were associated with increased expression of Foxa2, Sox17, AFP, and GATA4 on the EB periphery. Our data suggest that mild hypoxia facilitates the slow mitotic division of hESCs in long-term culture and reduces the frequency of chromosomal abnormalities and apoptosis. In addition, hypoxia promotes the differentiation of EBs into extraembryonic endoderm.

The Arabidopsis SOS5 Locus Encodes a Putative Cell Surface Adhesion Protein and Is Required for Normal Cell Expansion

PubMed Central

Shi, Huazhong; Kim, YongSig; Guo, Yan; Stevenson, Becky; Zhu, Jian-Kang

2003-01-01

Cell surface proteoglycans have been implicated in many aspects of plant growth and development, but genetic evidence supporting their function has been lacking. Here, we report that the Salt Overly Sensitive5 (SOS5) gene encodes a putative cell surface adhesion protein and is required for normal cell expansion. The sos5 mutant was isolated in a screen for Arabidopsis salt-hypersensitive mutants. Under salt stress, the root tips of sos5 mutant plants swell and root growth is arrested. The root-swelling phenotype is caused by abnormal expansion of epidermal, cortical, and endodermal cells. The SOS5 gene was isolated through map-based cloning. The predicted SOS5 protein contains an N-terminal signal sequence for plasma membrane localization, two arabinogalactan protein–like domains, two fasciclin-like domains, and a C-terminal glycosylphosphatidylinositol lipid anchor signal sequence. The presence of fasciclin-like domains, which typically are found in animal cell adhesion proteins, suggests a role for SOS5 in cell-to-cell adhesion in plants. The SOS5 protein was present at the outer surface of the plasma membrane. The cell walls are thinner in the sos5 mutant, and those between neighboring epidermal and cortical cells in sos5 roots appear less organized. SOS5 is expressed ubiquitously in all plant organs and tissues, including guard cells in the leaf. PMID:12509519

Catalase characterization and implication in bleaching of a symbiotic sea anemone.

PubMed

Merle, Pierre-Laurent; Sabourault, Cécile; Richier, Sophie; Allemand, Denis; Furla, Paola

2007-01-15

Symbiotic cnidarians are marine invertebrates harboring photosynthesizing microalgae (named zooxanthellae), which produce great amounts of oxygen and free radicals upon illumination. Studying antioxidative balance is then crucial to understanding how symbiotic cnidarians cope with ROS production. In particular, it is suspected that oxidative stress triggers cnidarian bleaching, i.e., the expulsion of zooxanthellae from the animal host, responsible for symbiotic cnidarian mass mortality worldwide. This study therefore investigates catalase antioxidant enzymes and their role in bleaching of the temperate symbiotic sea anemone Anemonia viridis. Using specific separation of animal tissues (ectoderm and endoderm) from the symbionts (zooxanthellae), spectrophotometric assays and native PAGE revealed both tissue-specific and activity pattern distribution of two catalase electrophoretypes, E1 and E2. E1, expressed in all three tissues, presents high sensitivity to the catalase inhibitor aminotriazole (ATZ) and elevated temperatures. The ectodermal E1 form is responsible for 67% of total catalase activity. The E2 form, expressed only within zooxanthellae and their host endodermal cells, displays low sensitivity to ATZ and relative thermostability. We further cloned an ectodermal catalase, which shares 68% identity with mammalian monofunctional catalases. Last, 6 days of exposure of whole sea anemones to ATZ (0.5 mM) led to effective catalase inhibition and initiated symbiont expulsion. This demonstrates the crucial role of this enzyme in cnidarian bleaching, a phenomenon responsible for worldwide climate-change-induced mass mortalities, with catastrophic consequences for marine biodiversity.

Urocortin 3 Marks Mature Human Primary and Embryonic Stem Cell-Derived Pancreatic Alpha and Beta Cells

PubMed Central

van der Meulen, Talitha; Xie, Ruiyu; Kelly, Olivia G.; Vale, Wylie W.; Sander, Maike; Huising, Mark O.

2012-01-01

The peptide hormone Urocortin 3 (Ucn 3) is abundantly and exclusively expressed in mouse pancreatic beta cells where it regulates insulin secretion. Here we demonstrate that Ucn 3 first appears at embryonic day (E) 17.5 and, from approximately postnatal day (p) 7 and onwards throughout adult life, becomes a unifying and exclusive feature of mouse beta cells. These observations identify Ucn 3 as a potential beta cell maturation marker. To determine whether Ucn 3 is similarly restricted to beta cells in humans, we conducted comprehensive immunohistochemistry and gene expression experiments on macaque and human pancreas and sorted primary human islet cells. This revealed that Ucn 3 is not restricted to the beta cell lineage in primates, but is also expressed in alpha cells. To substantiate these findings, we analyzed human embryonic stem cell (hESC)-derived pancreatic endoderm that differentiates into mature endocrine cells upon engraftment in mice. Ucn 3 expression in hESC-derived grafts increased robustly upon differentiation into mature endocrine cells and localized to both alpha and beta cells. Collectively, these observations confirm that Ucn 3 is expressed in adult beta cells in both mouse and human and appears late in beta cell differentiation. Expression of Pdx1, Nkx6.1 and PC1/3 in hESC-derived Ucn 3+ beta cells supports this. However, the expression of Ucn 3 in primary and hESC-derived alpha cells demonstrates that human Ucn 3 is not exclusive to the beta cell lineage but is a general marker for both the alpha and beta cell lineages. Ucn 3+ hESC-derived alpha cells do not express Nkx6.1, Pdx1 or PC1/3 in agreement with the presence of a separate population of Ucn 3+ alpha cells. Our study highlights important species differences in Ucn 3 expression, which have implications for its utility as a marker to identify mature beta cells in (re)programming strategies. PMID:23251699

The Sox17CreERT2 knock-in mouse line displays spatiotemporal activation of Cre recombinase in distinct Sox17 lineage progenitors.

PubMed

Engert, Silvia; Burtscher, Ingo; Kalali, Behnam; Gerhard, Markus; Lickert, Heiko

2013-11-01

The HMG-box transcription factor Sox17 is essential for endoderm formation, vascular development, and definitive hematopoiesis. To investigate the fate of distinct Sox17-expressing progenitor cells in a spatiotemporal manner, we generated a hormone-inducible CreERT2 knock-in mouse line. By homologous recombination we fused a codon improved, ligand-dependent estrogen receptor Cre recombinase by an intervening viral T2A sequence for co-translational cleavage to the 3' coding region of Sox17. Induction of Cre activity by administration of tamoxifen at defined time points of early mouse development and subsequent genetic lineage tracing confirmed the inducibility and tissue specificity of Cre recombination. Furthermore, Cre activity could be selectively induced in extra-embryonic and embryonic endoderm lineages, the primitive gut tube, and in endothelial cells of the vascular system as well as in the hemogenic endothelium of the dorsal aorta. The Sox17CreERT2 mouse line therefore represents a new tool for genetic lineage tracing in a tissue-specific manner and in addition enables lineage-restricted functional analysis. Copyright © 2013 Wiley Periodicals, Inc.

Involvement of activator protein 1 complexes in the epithelium-specific activation of the laminin gamma2-chain gene promoter by hepatocyte growth factor (scatter factor).

PubMed Central

Olsen, J; Lefebvre, O; Fritsch, C; Troelsen, J T; Orian-Rousseau, V; Kedinger, M; Simon-Assmann, P

2000-01-01

Laminin-5 is a trimer of laminin alpha3, beta3 and gamma2 chains that is found in the intestinal basement membrane. Deposition of the laminin gamma2 chain at the basement membrane is of great interest because it undergoes a developmental shift in its cellular expression. Here we study the regulatory elements that control basal and cytokine-activated transcriptional expression of the LAMC2 gene, which encodes the laminin gamma2 chain. By using transient transfection experiments we demonstrated the presence of constitutive and cytokine-responsive cis-elements. Comparison of the transcriptional activity of the LAMC2 promoter in the epithelial HT29mtx cells with that in small-intestinal fibroblastic cells (C20 cells) led us to conclude that two regions with constitutive epithelium-specific activity are present between positions -1.2 and -0.12 kb. This was further validated by transfections of primary foetal intestinal endoderm and mesenchyme. A 2.5 kb portion of the LAMC2 5' flanking region was equally responsive to PMA and hepatocyte growth factor (HGF), whereas it was less responsive to transforming growth factor beta1. A minimal promoter limited to the initial 120 bp upstream of the transcriptional start site maintained inducibility by PMA and HGF. This short promoter fragment contains two activator protein 1 (AP-1) elements and the 5'-most of these is a composite AP-1/Sp1 element. The 5'AP-1 element is crucial to the HGF-mediated activity of the promoter; analysis of interacting nuclear proteins demonstrated that AP-1 proteins containing JunD mediate the response to HGF. PMID:10749670

Diverse effects of dimethyl sulfoxide (DMSO) on the differentiation potential of human embryonic stem cells.

PubMed

Pal, Rajarshi; Mamidi, Murali Krishna; Das, Anjan Kumar; Bhonde, Ramesh

2012-04-01

In vitro disease modeling using pluripotent stem cells can be a fast track screening tool for toxicological testing of candidate drug molecules. Dimethyl sulfoxide (DMSO) is one of the most commonly used solvents in drug screening. In the present investigation, we exposed 14- to 21-day-old embryoid bodies (EBs) to three different concentrations of DMSO [0.01% (low dose), 0.1% (medium dose) and 1.0% (high dose)] to identify the safest dose that could effectively be used as solvent. We found that DMSO treatment substantially altered the morphology and attachment of cells in concurrence with a significant reduction in cell viability in a dose-dependent manner. Gene expression studies revealed a selective downregulation of key markers associated with stemness (Oct-4, Sox-2, Nanog and Rex-1); ectoderm (Nestin, TuJ1, NEFH and Keratin-15); mesoderm (HAND-1, MEF-2C, GATA-4 and cardiac-actin); and endoderm (SOX-17, HNF-3β, GATA-6 and albumin), indicating an aberrant and untimely differentiation trajectory. Furthermore, immunocytochemistry, flow cytometry and histological analyses demonstrated substantial decrease in the levels of albumin and CK-18 proteins coupled with a massive reduction in the number of cells positive for PAS staining, implicating reduced deposits of glycogen. Our study advocates for the first time that DMSO exposure not only affects the phenotypic characteristics but also induces significant alteration in gene expression, protein content and functionality of the differentiated hepatic cells. Overall, our experiments warrant that hESC-based assays can provide timely alerts about the outcome of widespread applications of DMSO as drug solvent, cryoprotectant and differentiating agent.

Allele-specific control of replication timing and genome organization during development.

PubMed

Rivera-Mulia, Juan Carlos; Dimond, Andrew; Vera, Daniel; Trevilla-Garcia, Claudia; Sasaki, Takayo; Zimmerman, Jared; Dupont, Catherine; Gribnau, Joost; Fraser, Peter; Gilbert, David M

2018-05-07

DNA replication occurs in a defined temporal order known as the replication-timing (RT) program. RT is regulated during development in discrete chromosomal units, coordinated with transcriptional activity and 3D genome organization. Here, we derived distinct cell types from F1 hybrid musculus X castaneus mouse crosses and exploited the high single nucleotide polymorphism (SNP) density to characterize allelic differences in RT (Repli-seq), genome organization (Hi-C and promoter-capture Hi-C), gene expression (total nuclear RNA-seq) and chromatin accessibility (ATAC-seq). We also present HARP: a new computational tool for sorting SNPs in phased genomes to efficiently measure allele-specific genome-wide data. Analysis of six different hybrid mESC clones with different genomes (C57BL/6, 129/sv and CAST/Ei), parental configurations and gender revealed significant RT asynchrony between alleles across ~12% of the autosomal genome linked to sub-species genomes but not to parental origin, growth conditions or gender. RT asynchrony in mESCs strongly correlated with changes in Hi-C compartments between alleles but not SNP density, gene expression, imprinting or chromatin accessibility. We then tracked mESC RT asynchronous regions during development by analyzing differentiated cell types including extraembryonic endoderm stem (XEN) cells, 4 male and female primary mouse embryonic fibroblasts (MEFs) and neural precursor cells (NPCs) differentiated in vitro from mESCs with opposite parental configurations. We found that RT asynchrony and allelic discordance in Hi-C compartments seen in mESCs was largely lost in all differentiated cell types, coordinated with a more uniform Hi-C compartment arrangement, suggesting that genome organization of homologues converges to similar folding patterns during cell fate commitment. Published by Cold Spring Harbor Laboratory Press.

Pancreas-specific deletion of mouse Gata4 and Gata6 causes pancreatic agenesis

PubMed Central

Xuan, Shouhong; Borok, Matthew J.; Decker, Kimberly J.; Battle, Michele A.; Duncan, Stephen A.; Hale, Michael A.; Macdonald, Raymond J.; Sussel, Lori

2012-01-01

Pancreatic agenesis is a human disorder caused by defects in pancreas development. To date, only a few genes have been linked to pancreatic agenesis in humans, with mutations in pancreatic and duodenal homeobox 1 (PDX1) and pancreas-specific transcription factor 1a (PTF1A) reported in only 5 families with described cases. Recently, mutations in GATA6 have been identified in a large percentage of human cases, and a GATA4 mutant allele has been implicated in a single case. In the mouse, Gata4 and Gata6 are expressed in several endoderm-derived tissues, including the pancreas. To analyze the functions of GATA4 and/or GATA6 during mouse pancreatic development, we generated pancreas-specific deletions of Gata4 and Gata6. Surprisingly, loss of either Gata4 or Gata6 in the pancreas resulted in only mild pancreatic defects, which resolved postnatally. However, simultaneous deletion of both Gata4 and Gata6 in the pancreas caused severe pancreatic agenesis due to disruption of pancreatic progenitor cell proliferation, defects in branching morphogenesis, and a subsequent failure to induce the differentiation of progenitor cells expressing carboxypeptidase A1 (CPA1) and neurogenin 3 (NEUROG3). These studies address the conserved and nonconserved mechanisms underlying GATA4 and GATA6 function during pancreas development and provide a new mouse model to characterize the underlying developmental defects associated with pancreatic agenesis. PMID:23006325

Scube3 Is Expressed in Multiple Tissues during Development but Is Dispensable for Embryonic Survival in the Mouse

PubMed Central

Xavier, Guilherme M.; Panousopoulos, Leonidas; Cobourne, Martyn T.

2013-01-01

The vertebrate Scube family consists of three independent members Scube1-3; which encode secreted cell surface-associated membrane glycoproteins that share a domain organization of at least five recognizable motifs and the ability to both homo- and heterodimerize. There is recent biochemical evidence to suggest that Scube2 is directly involved in Hedgehog signaling, acting co-operatively with Dispatched to mediate the release in soluble form of cholesterol and palmitate-modified Hedgehog ligand during long-range activity. Indeed, in the zebrafish myotome, all three Scube proteins can subtly promote Hedgehog signal transduction in a non-cell autonomous manner. In order to further investigate the role of Scube genes during development, we have generated mice with targeted inactivation of Scube3. Despite a dynamic developmental expression pattern, with transcripts present in neuroectoderm, endoderm and endochondral tissues, particularly within the craniofacial region; an absence of Scube3 function results in no overt embryonic phenotype in the mouse. Mutant mice are born at expected Mendelian ratios, are both viable and fertile, and seemingly retain normal Hedgehog signaling activity in craniofacial tissues. These findings suggest that in the mouse, Scube3 is dispensable for normal development; however, they do not exclude the possibility of a co-operative role for Scube3 with other Scube members during embryogenesis or a potential role in adult tissue homeostasis over the long-term. PMID:23383134

Resveratrol Ameliorates the Maturation Process of β-Cell-Like Cells Obtained from an Optimized Differentiation Protocol of Human Embryonic Stem Cells

PubMed Central

Pezzolla, Daniela; López-Beas, Javier; Lachaud, Christian C.; Domínguez-Rodríguez, Alejandro; Smani, Tarik; Hmadcha, Abdelkrim; Soria, Bernat

2015-01-01

Human embryonic stem cells (hESCs) retain the extraordinary capacity to differentiate into different cell types of an adult organism, including pancreatic β-cells. For this particular lineage, although a lot of effort has been made in the last ten years to achieve an efficient and reproducible differentiation protocol, it was not until recently that this aim was roughly accomplished. Besides, several studies evidenced the impact of resveratrol (RSV) on insulin secretion, even though the mechanism by which this polyphenol potentiates glucose-stimulated insulin secretion (GSIS) is still not clear. The aim of this study was to optimize an efficient differentiation protocol that mimics in vivo pancreatic organogenesis and to investigate whether RSV may improve the final maturation step to obtain functional insulin-secreting cells. Our results indicate that treatment of hESCs (HS-181) with activin-A induced definitive endoderm differentiation as detected by the expression of SOX17 and FOXA2. Addition of retinoic acid (RA), Noggin and Cyclopamine promoted pancreatic differentiation as indicated by the expression of the early pancreatic progenitor markers ISL1, NGN3 and PDX1. Moreover, during maturation in suspension culture, differentiating cells assembled in islet-like clusters, which expressed specific endocrine markers such as PDX1, SST, GCG and INS. Similar results were confirmed with the human induced Pluripotent Stem Cell (hiPSC) line MSUH-001. Finally, differentiation protocols incorporating RSV treatment yielded numerous insulin-positive cells, induced significantly higher PDX1 expression and were able to transiently normalize glycaemia when transplanted in streptozotocin (STZ) induced diabetic mice thus promoting its survival. In conclusion, our strategy allows the efficient differentiation of hESCs into pancreatic endoderm capable of generating β-cell-like cells and demonstrates that RSV improves the maturation process. PMID:25774684

Gene Regulatory Networks governing lung specification

PubMed Central

Rankin, Scott A.; Zorn, Aaron M.

2014-01-01

The epithelial lining of the respiratory system originates from a small group of progenitor cells in the ventral foregut endoderm of the early embryo. Research in the last decade has revealed a number of paracrine signaling pathways that are critical for the development of these respiratory progenitors. In the post genomic era the challenge now is to figure out at the genome wide level how these different signaling pathways and their downstream transcription factors interact in a complex “gene regulatory network” (GRN) to orchestrate early lung development. In this prospective we review our growing understanding of the GRN governing lung specification. We discuss key gaps in our knowledge and describe emerging opportunities that will soon provide an unprecedented understanding of lung development and accelerate our ability to apply this knowledge to regenerative medicine. PMID:24644080

Applications of patient-specific induced pluripotent stem cells; focused on disease modeling, drug screening and therapeutic potentials for liver disease.

PubMed

Chun, Yong Soon; Chaudhari, Pooja; Jang, Yoon-Young

2010-12-14

The recent advances in the induced pluripotent stem cell (iPSC) research have significantly changed our perspectives on regenerative medicine by providing researchers with a unique tool to derive disease-specific stem cells for study. In this review, we describe the human iPSC generation from developmentally diverse origins (i.e. endoderm-, mesoderm-, and ectoderm- tissue derived human iPSCs) and multistage hepatic differentiation protocols, and discuss both basic and clinical applications of these cells including disease modeling, drug toxicity screening/drug discovery, gene therapy and cell replacement therapy.

The gravitropism defective 2 Mutants of Arabidopsis Are Deficient in a Protein Implicated in Endocytosis in Caenorhabditis elegans1[w

PubMed Central

Silady, Rebecca A.; Kato, Takehide; Lukowitz, Wolfgang; Sieber, Patrick; Tasaka, Masao; Somerville, Chris R.

2004-01-01

The gravitropism defective 2 (grv2) mutants of Arabidopsis show reduced shoot phototropism and gravitropism. Amyloplasts in the shoot endodermal cells of grv2 do not sediment to the same degree as in wild type. The GRV2 gene encodes a 277-kD polypeptide that is 42% similar to the Caenorhabditis elegans RME-8 protein, which is required for endocytosis. We hypothesize that a defect in endocytosis may affect both the initial gravity sensing via amyloplasts sedimentation and the subsequent more general tropic growth response. PMID:15466218

Cell fate regulation in early mammalian development

NASA Astrophysics Data System (ADS)

Oron, Efrat; Ivanova, Natalia

2012-08-01

Preimplantation development in mammals encompasses a period from fertilization to implantation and results in formation of a blastocyst composed of three distinct cell lineages: epiblast, trophectoderm and primitive endoderm. The epiblast gives rise to the organism, while the trophectoderm and the primitive endoderm contribute to extraembryonic tissues that support embryo development after implantation. In many vertebrates, such as frog or fish, maternally supplied lineage determinants are partitioned within the egg. Cell cleavage that follows fertilization results in polarization of these factors between the individual blastomeres, which become restricted in their developmental fate. In contrast, the mouse oocyte and zygote lack clear polarity and, until the eight-cell stage, individual blastomeres retain the potential to form all lineages. How are cell lineages specified in the absence of a maternally supplied blueprint? This is a fundamental question in the field of developmental biology. The answer to this question lies in understanding the cell-cell interactions and gene networks involved in embryonic development prior to implantation and using this knowledge to create testable models of the developmental processes that govern cell fates. We provide an overview of classic and contemporary models of early lineage development in the mouse and discuss the emerging body of work that highlights similarities and differences between blastocyst development in the mouse and other mammalian species.

Developmental characteristics of somatic cell hybrids between totipotent mouse teratocarcinoma and rat intestinal villus cells.

PubMed

van der Kamp, A W; Roza-de Jongh, E J; Houwen, R H; Magrane, G G; van Dongen, J M; Evans, M J

1984-09-01

Hybrids between mouse PCC4-azal teratocarcinoma cells and rat epithelial intestinal villus cells (PCI hybrids) are phenotypically teratocarcinoma cells. They express several teratocarcinoma-specific traits but do not express functions specific for differentiated cells. Tumour formation is partially or completely suppressed. Some of the hybrids show more extensive differentiation both in vitro and in vivo than the PCC4-azal parental line. The hybrids are capable of endoderm formation in monolayer cultures and of the formation of embryoid bodies in suspension cultures. Two of the tumour-forming hybrids generate derivatives of all three germ layers, whereas differentiation in the PCC4-azal tumours is restricted to the formation of primitive neuronal tissues.

Pax2.1 is required for the development of thyroid follicles in zebrafish.

PubMed

Wendl, Thomas; Lun, Klaus; Mione, Marina; Favor, Jack; Brand, Michael; Wilson, Stephen W; Rohr, Klaus B

2002-08-01

The thyroid gland is an organ primarily composed of endoderm-derived follicular cells. Although disturbed embryonic development of the thyroid gland leads to congenital hypothyroidism in humans and mammals, the underlying principles of thyroid organogenesis are largely unknown. In this study, we introduce zebrafish as a model to investigate the molecular and genetic mechanisms that control thyroid development. Marker gene expression suggests that the molecular pathways of early thyroid development are essentially conserved between fish and mammals. However during larval stages, we find both conserved and divergent features of development compared with mammals. A major difference is that in fish, we find evidence for hormone production not only in thyroid follicular cells, but also in an anterior non-follicular group of cells. We show that pax2.1 and pax8, members of the zebrafish pax2/5/8 paralogue group, are expressed in the thyroid primordium. Whereas in mice, only Pax8 has a function during thyroid development, analysis of the zebrafish pax2.1 mutant no isthmus (noi(-/-)) demonstrates that pax2.1 has a role comparable with mouse Pax8 in differentiation of the thyroid follicular cells. Early steps of thyroid development are normal in noi(-/-), but later expression of molecular markers is lost and the formation of follicles fails. Interestingly, the anterior non-follicular site of thyroid hormone production is not affected in noi(-/-). Thus, in zebrafish, some remaining thyroid hormone synthesis takes place independent of the pathway leading to thyroid follicle formation. We suggest that the noi(-/-) mutant serves as a new zebrafish model for hypothyroidism.

Enrichment of human embryonic stem cell-derived NKX6.1-expressing pancreatic progenitor cells accelerates the maturation of insulin-secreting cells in vivo.

PubMed

Rezania, Alireza; Bruin, Jennifer E; Xu, Jean; Narayan, Kavitha; Fox, Jessica K; O'Neil, John J; Kieffer, Timothy J

2013-11-01

Human embryonic stem cells (hESCs) are considered a potential alternative to cadaveric islets as a source of transplantable cells for treating patients with diabetes. We previously described a differentiation protocol to generate pancreatic progenitor cells from hESCs, composed of mainly pancreatic endoderm (PDX1/NKX6.1-positive), endocrine precursors (NKX2.2/synaptophysin-positive, hormone/NKX6.1-negative), and polyhormonal cells (insulin/glucagon-positive, NKX6.1-negative). However, the relative contributions of NKX6.1-negative versus NKX6.1-positive cell fractions to the maturation of functional β-cells remained unclear. To address this question, we generated two distinct pancreatic progenitor cell populations using modified differentiation protocols. Prior to transplant, both populations contained a high proportion of PDX1-expressing cells (~85%-90%) but were distinguished by their relatively high (~80%) or low (~25%) expression of NKX6.1. NKX6.1-high and NKX6.1-low progenitor populations were transplanted subcutaneously within macroencapsulation devices into diabetic mice. Mice transplanted with NKX6.1-low cells remained hyperglycemic throughout the 5-month post-transplant period whereas diabetes was reversed in NKX6.1-high recipients within 3 months. Fasting human C-peptide levels were similar between groups throughout the study, but only NKX6.1-high grafts displayed robust meal-, glucose- and arginine-responsive insulin secretion as early as 3 months post-transplant. NKX6.1-low recipients displayed elevated fasting glucagon levels. Theracyte devices from both groups contained almost exclusively pancreatic endocrine tissue, but NKX6.1-high grafts contained a greater proportion of insulin-positive and somatostatin-positive cells, whereas NKX6.1-low grafts contained mainly glucagon-expressing cells. Insulin-positive cells in NKX6.1-high, but not NKX6.1-low grafts expressed nuclear MAFA. Collectively, this study demonstrates that a pancreatic endoderm-enriched population can mature into highly functional β-cells with only a minor contribution from the endocrine subpopulation. © AlphaMed Press.

Using Human Stem Cells to Study the Role of the Stroma in the Initiation of Prostate Cancer

DTIC Science & Technology

2011-03-01

alterations in the epithelium that drives the pr ogressive transformation of nor mal human cells into highly malignant derivatives. It is evident that...of tumor initiation, we propose to use normal human prostate epithelium generated from human embryonic stem cells (hESCs) in tissue recombination...serum free conditions for 5-8 days into endoderm in vitro. Confirm endoderm phenotype using immunohistochemistry and FACs analysis . We conducted

New insights from a high-resolution look at gastrulation in the sea urchin, Lytechinus variegatus.

PubMed

Martik, Megan L; McClay, David R

2017-12-01

Gastrulation is a complex orchestration of movements by cells that are specified early in development. Until now, classical convergent extension was considered to be the main contributor to sea urchin archenteron extension, and the relative contributions of cell divisions were unknown. Active migration of cells along the axis of extension was also not considered as a major factor in invagination. Cell transplantations plus live imaging were used to examine endoderm cell morphogenesis during gastrulation at high-resolution in the optically clear sea urchin embryo. The invagination sequence was imaged throughout gastrulation. One of the eight macromeres was replaced by a fluorescently labeled macromere at the 32 cell stage. At gastrulation those patches of fluorescent endoderm cell progeny initially about 4 cells wide, released a column of cells about 2 cells wide early in gastrulation and then often this column narrowed to one cell wide by the end of archenteron lengthening. The primary movement of the column of cells was in the direction of elongation of the archenteron with the narrowing (convergence) occurring as one of the two cells moved ahead of its neighbor. As the column narrowed, the labeled endoderm cells generally remained as a contiguous population of cells, rarely separated by intrusion of a lateral unlabeled cell. This longitudinal cell migration mechanism was assessed quantitatively and accounted for almost 90% of the elongation process. Much of the extension was the contribution of Veg2 endoderm with a minor contribution late in gastrulation by Veg1 endoderm cells. We also analyzed the contribution of cell divisions to elongation. Endoderm cells in Lytechinus variagatus were determined to go through approximately one cell doubling during gastrulation. That doubling occurs without a net increase in cell mass, but the question remained as to whether oriented divisions might contribute to archenteron elongation. We learned that indeed there was a biased orientation of cell divisions along the plane of archenteron elongation, but when the impact of that bias was analyzed quantitatively, it contributed a maximum 15% to the total elongation of the gut. The major driver of archenteron elongation in the sea urchin, Lytechinus variagatus, is directed movement of Veg2 endoderm cells as a narrowing column along the plane of elongation. The narrowing occurs as cells in the column converge as they migrate, so that the combination of migration and the angular convergence provide the major component of the lengthening. A minor contributor to elongation is oriented cell divisions that contribute to the lengthening but no more than about 15%. Copyright © 2017 Elsevier B.V. All rights reserved.

The small GTPase Arf6 regulates sea urchin morphogenesis

PubMed Central

Stepicheva, Nadezda A.; Dumas, Megan; Kobi, Priscilla; Donaldson, Julie G.; Song, Jia L.

2017-01-01

The small GTPase Arf6 is a conserved protein that is expressed in all metazoans. Arf6 remodels cytoskeletal actin and mediates membrane protein trafficking between the plasma membrane in its active form and endosomal compartments in its inactive form. While a rich knowledge exists for the cellular functions of Arf6, relatively little is known about its physiological role in development. This study examines the function of Arf6 in mediating cellular morphogenesis in early development. We dissect the function of Arf6 with a loss-of-function morpholino and constitutively active Arf6-Q67L construct. We focus on the two cell types that undergo active directed migration: the primary mesenchyme cells (PMCs) that give rise to the sea urchin skeleton and endodermal cells that form the gut. Our results indicate that Arf6 plays an important role in skeleton formation and PMC migration, in part due to its ability to remodel actin. We also found that embryos injected with Arf6 morpholino have gastrulation defects and embryos injected with constitutively active Arf6 have endodermal cells detached from the gut epithelium with decreased junctional cadherin staining, indicating that Arf6 may mediate the recycling of cadherin. Thus, Arf6 impacts cells that undergo coordinated movement to form embryonic structures in the developing embryo. PMID:28188999

Activin A Modulates CRIPTO-1/HNF4α+ Cells to Guide Cardiac Differentiation from Human Embryonic Stem Cells

PubMed Central

Duelen, Robin; Gilbert, Guillaume; Patel, Abdulsamie; de Schaetzen, Nathalie; De Waele, Liesbeth; Roderick, Llewelyn; Sipido, Karin R.; Verfaillie, Catherine M.; Buyse, Gunnar M.

2017-01-01

The use of human pluripotent stem cells in basic and translational cardiac research requires efficient differentiation protocols towards cardiomyocytes. In vitro differentiation yields heterogeneous populations of ventricular-, atrial-, and nodal-like cells hindering their potential applications in regenerative therapies. We described the effect of the growth factor Activin A during early human embryonic stem cell fate determination in cardiac differentiation. Addition of high levels of Activin A during embryoid body cardiac differentiation augmented the generation of endoderm derivatives, which in turn promoted cardiomyocyte differentiation. Moreover, a dose-dependent increase in the coreceptor expression of the TGF-β superfamily member CRIPTO-1 was observed in response to Activin A. We hypothesized that interactions between cells derived from meso- and endodermal lineages in embryoid bodies contributed to improved cell maturation in early stages of cardiac differentiation, improving the beating frequency and the percentage of contracting embryoid bodies. Activin A did not seem to affect the properties of cardiomyocytes at later stages of differentiation, measuring action potentials, and intracellular Ca2+ dynamics. These findings are relevant for improving our understanding on human heart development, and the proposed protocol could be further explored to obtain cardiomyocytes with functional phenotypes, similar to those observed in adult cardiac myocytes. PMID:28163723

The problem of the origin of primordial germ cells (PGCs) in vertebrates: historical review and a possible solution.

PubMed

Pilato, Giovanni; D'Urso, Vera; Viglianisi, Fabio; Sammartano, Francesca; Sabella, Giorgio; Lisi, Oscar

2013-01-01

A concise review of the articles about the origin of primordial germ cells (PGCs) in vertebrates is provided. Differences among various taxa concerning the origin of PGCs, not easily understandable on the base of traditional knowledge, are pointed out. All those differences can be explained taking into consideration the recent “theory of the endoderm as secondary layer”. That theory allows us to understand that those differences are only apparent, being related to modifications of stages of the consequent embryogeny, overall, to a different amount of yolk in the egg. Eggs very rich in yolk became meroblastic, and the portion of primordial ectomesenchyme destined to give rise to a part of the mesoderm and the PGCs separates early from the part destined to give rise to the rest of the mesoderm and to the digestive endoderm in order to form the vitelline hypoblast lamina. To this lamina, in contrast to the traditional interpretation, a mesodermal, not endodermal, origin must be attributed. With the misunderstanding regarding the origin of this lamina clarified, all the differences about the origin of PGCs disappears. Furthermore, in taxa where PGCs were considered to be of endodermal origin, they too have a mesodermal origin. Considering that a mesodermal origin of PGCs has been demonstrated in all sponges and cnidarians, as well, a unique, mesodermal origin of germinal cells in all pluricellular animals results.

Developmental potential of muscle cell progenitors and the myogenic factor SUM-1 in the sea urchin embryo.

PubMed

Venuti, J M; Gan, L; Kozlowski, M T; Klein, W H

1993-04-01

During sea urchin development, esophageal muscle arises from secondary mesenchyme cells, descendants of the vegetal plate that delaminate from the coelomic epithelium at the end of gastrulation. In lithium-induced exogastrulae, where vegetal plate descendants evert rather than invaginate, myogenesis occurs normally, indicating that myocyte progenitors do not have to be near the future stomodeum for differentiation to occur. Vegetal plate descendants isolated along with the extracellular matrix at different times during gastrulation produce differentiated myocytes in culture as monitored by staining with a myosin heavy chain antibody. Vegetal isolates prepared at mid-gastrulation or later consistently produce differentiated myocytes whose form and position resembled their counterparts in the intact embryo, whereas vegetal isolates prepared a few hours earlier while capable of gut differentiation, as evidenced by the de novo synthesis of the endodermal surface marker Endo 1, did not produce differentiated myocytes. These results suggest that sometime after early gastrulation, a subset of secondary mesenchyme cells are competent to differentiate into muscle cells. RNase protection assays showed that the accumulation of sea urchin myogenic factor (SUM-1) mRNA is likely to be coincident with the earliest demonstrable commitment of myogenic precursors. Premature expression of SUM-1 coding sequences in mesenchyme blastulae resulted in the activation of muscle-specific enhancer elements, demonstrating that SUM-1 can function precociously in the early embryo. However, SUM-1 expressed in this manner did not activate the endogenous MHC gene, nor induce premature or ectopic production of muscle cells.

Antagonistic BMP–cWNT signaling in the cnidarian Nematostella vectensis reveals insight into the evolution of mesoderm

PubMed Central

Wijesena, Naveen; Simmons, David K.

2017-01-01

Gastrulation was arguably the key evolutionary innovation that enabled metazoan diversification, leading to the formation of distinct germ layers and specialized tissues. Differential gene expression specifying cell fate is governed by the inputs of intracellular and/or extracellular signals. Beta-catenin/Tcf and the TGF-beta bone morphogenetic protein (BMP) provide critical molecular signaling inputs during germ layer specification in bilaterian metazoans, but there has been no direct experimental evidence for a specific role for BMP signaling during endomesoderm specification in the early branching metazoan Nematostella vectensis (an anthozoan cnidarian). Using forward transcriptomics, we show that beta-catenin/Tcf signaling and BMP2/4 signaling provide differential inputs into the cnidarian endomesodermal gene regulatory network (GRN) at the onset of gastrulation (24 h postfertilization) in N. vectensis. Surprisingly, beta-catenin/Tcf signaling and BMP2/4 signaling regulate a subset of common downstream target genes in the GRN in opposite ways, leading to the spatial and temporal differentiation of fields of cells in the developing embryo. Thus, we show that regulatory interactions between beta-catenin/Tcf signaling and BMP2/4 signaling are required for the specification and determination of different embryonic regions and the patterning of the oral–aboral axis in Nematostella. We also show functionally that the conserved “kernel” of the bilaterian heart mesoderm GRN is operational in N. vectensis, which reinforces the hypothesis that the endoderm and mesoderm in triploblastic bilaterians evolved from the bifunctional endomesoderm (gastrodermis) of a diploblastic ancestor, and that slow rhythmic contractions might have been one of the earliest functions of mesodermal tissue. PMID:28652368

Efficient generation of functional CFTR-expressing airway epithelial cells from human pluripotent stem cells.

PubMed

Wong, Amy P; Chin, Stephanie; Xia, Sunny; Garner, Jodi; Bear, Christine E; Rossant, Janet

2015-03-01

Airway epithelial cells are of great interest for research on lung development, regeneration and disease modeling. This protocol describes how to generate cystic fibrosis (CF) transmembrane conductance regulator protein (CFTR)-expressing airway epithelial cells from human pluripotent stem cells (PSCs). The stepwise approach from PSC culture to differentiation into progenitors and then mature epithelia with apical CFTR activity is outlined. Human PSCs that were inefficient at endoderm differentiation using our previous lung differentiation protocol were able to generate substantial lung progenitor cell populations. Augmented CFTR activity can be observed in all cultures as early as at 35 d of differentiation, and full maturation of the cells in air-liquid interface cultures occurs in <5 weeks. This protocol can be used for drug discovery, tissue regeneration or disease modeling.

Endodermal ABA Signaling Promotes Lateral Root Quiescence during Salt Stress in Arabidopsis Seedlings[C][W

PubMed Central

Duan, Lina; Dietrich, Daniela; Ng, Chong Han; Chan, Penny Mei Yeen; Bhalerao, Rishikesh; Bennett, Malcolm J.; Dinneny, José R.

2013-01-01

The endodermal tissue layer is found in the roots of vascular plants and functions as a semipermeable barrier, regulating the transport of solutes from the soil into the vascular stream. As a gateway for solutes, the endodermis may also serve as an important site for sensing and responding to useful or toxic substances in the environment. Here, we show that high salinity, an environmental stress widely impacting agricultural land, regulates growth of the seedling root system through a signaling network operating primarily in the endodermis. We report that salt stress induces an extended quiescent phase in postemergence lateral roots (LRs) whereby the rate of growth is suppressed for several days before recovery begins. Quiescence is correlated with sustained abscisic acid (ABA) response in LRs and is dependent upon genes necessary for ABA biosynthesis, signaling, and transcriptional regulation. We use a tissue-specific strategy to identify the key cell layers where ABA signaling acts to regulate growth. In the endodermis, misexpression of the ABA insensitive1-1 mutant protein, which dominantly inhibits ABA signaling, leads to a substantial recovery in LR growth under salt stress conditions. Gibberellic acid signaling, which antagonizes the ABA pathway, also acts primarily in the endodermis, and we define the crosstalk between these two hormones. Our results identify the endodermis as a gateway with an ABA-dependent guard, which prevents root growth into saline environments. PMID:23341337

Endodermal Hedgehog signals modulate Notch pathway activity in the developing digestive tract mesenchyme

PubMed Central

Kim, Tae-Hee; Kim, Byeong-Moo; Mao, Junhao; Rowan, Sheldon; Shivdasani, Ramesh A.

2011-01-01

The digestive tract epithelium and its adjoining mesenchyme undergo coordinated patterning and growth during development. The signals they exchange in the process are not fully characterized but include ligands of the Hedgehog (Hh) family, which originate in the epithelium and are necessary for mesenchymal cells to expand in number and drive elongation of the developing gut tube. The Notch signaling pathway has known requirements in fetal and adult intestinal epithelial progenitors. We detected Notch pathway activity in the embryonic gut mesenchyme and used conditional knockout mice to study its function. Selective disruption of the Notch effector gene RBP-Jκ (Rbpj) in the mesenchyme caused progressive loss of subepithelial fibroblasts and abbreviated gut length, revealing an unexpected requirement in this compartment. Surprisingly, constitutive Notch activity also induced rapid mesenchymal cell loss and impaired organogenesis, probably resulting from increased cell death and suggesting the need for a delicate balance in Notch signaling. Because digestive tract anomalies in mouse embryos with excess Notch activity phenocopy the absence of Hh signaling, we postulated that endodermal Hh restrains mesenchymal Notch pathway activity. Indeed, Hh-deficient embryos showed Notch overactivity in their defective gut mesenchyme and exposure to recombinant sonic hedgehog could override Notch-induced death of cultured fetal gut mesenchymal cells. These results reveal unexpected interactions between prominent signals in gastrointestinal development and provide a coherent explanation for Hh requirements in mesenchymal cell survival and organ growth. PMID:21750033

Fibroblast growth factor-2 expression in the preimplantation equine conceptus and endometrium of pregnant and cyclic mares.

PubMed

de Ruijter-Villani, Marta; van Boxtel, Paula R M; Stout, Tom A E

2013-12-01

Uterine-derived growth factors and cytokines play essential roles in regulating preimplantation conceptus development. In several species, fibroblast growth factor-2 (FGF2) promotes embryogenesis, trophoblast cell migration, and adhesion. This study investigated mRNA expression for FGF2, its receptors (FGFR1-4), the activating factor FGF binding protein (FGF-BP) in equine endometrium and trophectoderm during early pregnancy and the estrous cycle, and localized FGF2 protein in both endometrium and conceptus tissues. FGF2, FGFRs1-4, and FGFBP mRNAs were expressed in endometrium throughout the estrous cycle and early pregnancy, and in days 14 to 28 conceptus membranes. FGF2 transcription was higher during estrus than on days 7 or 14 of diestrus, suggesting estrogen dependency. Endometrial expression of FGF2 mRNA and protein increased as pregnancy progressed from days 21 and day 28; FGF2 protein was localized predominantly in the luminal and glandular epithelium. FGF2 mRNA was detectable in trophectoderm from as early as day 14, and transcription and translation increased in day 21 and 28 allantochorion. FGF2 protein was localized mainly in the trophectoderm up to day 21 but was present in both trophectoderm and endoderm of day 28 allantochorion. FGFR1 mRNA was down-regulated in the endometrium at day 7 of diestrus but increased again by day 14. Gene expression for all of the FGFR2 splice variants, including FGFR2IIIc, was up-regulated during estrus. During early pregnancy, endometrial FGFR1 expression decreased, whereas FGFR2IIIc expression did not change. Conceptus mRNA expression for all FGFRs increased as pregnancy progressed. FGFBP expression remained unchanged in endometrium, but increased in the conceptus between days 14 and 28, suggesting a role in regulating FGF2 activity in the developing conceptus. We conclude that during weeks 3 and 4 of pregnancy, the equine endometrial epithelium produces FGF2, which may play a role in trophoblast development and adhesion. Copyright © 2013 Elsevier Inc. All rights reserved.

Serum-free differentiation of murine embryonic stem cells into alveolar type II epithelial cells.

PubMed

Winkler, Monica E; Mauritz, Christina; Groos, Stephanie; Kispert, Andreas; Menke, Sandra; Hoffmann, Anika; Gruh, Ina; Schwanke, Kristin; Haverich, Axel; Martin, Ulrich

2008-03-01

Alveolar type II (AT2) epithelial cells have important functions including the production of surfactant and regeneration of lost alveolar type I epithelial cells. The ability of in vitro production of AT2 cells would offer new therapeutic options in treating pulmonary injuries and disorders including genetically based surfactant deficiencies. Aiming at the generation of AT2-like cells, the differentiation of murine embryonic stem cells (mESCs) toward mesendodermal progenitors (MEPs) was optimized using a "Brachyury-eGFP-knock in" mESC line. eGFP expression demonstrated generation of up to 65% MEPs at day 4 after formation of embryoid bodies (EBs) under serum-free conditions. Plated EBs were further differentiated into AT2-like cells for a total of 25 days in serum-free media resulting in the expression of endodermal marker genes (FoxA2, Sox17, TTR, TTF-1) and of markers for distal lung epithelium (surfactant proteins (SP-) A, B, C, and D, CCSP, aquaporin 5). Notably, expression of SP-C as the only known AT2 cell specific marker could be detected after serum-induction as well as under serum-free conditions. Cytoplasmic localization of SP-C was demonstrated by confocal microscopy. The presence of AT2-like cells was confirmed by electron microscopy providing evidence for polarized cells with apical microvilli and lamellar body-like structures. Our results demonstrate the differentiation of AT2-like cells from mESCs after serum-induction and under serum-free conditions. The established serum-free differentiation protocol will facilitate the identification of key differentiation factors leading to a more specific and effective generation of AT2-like cells from ESCs.

Mechanotransductive cascade of Myo-II-dependent mesoderm and endoderm invaginations in embryo gastrulation

PubMed Central

Mitrossilis, Démosthène; Röper, Jens-Christian; Le Roy, Damien; Driquez, Benjamin; Michel, Aude; Ménager, Christine; Shaw, Gorky; Le Denmat, Simon; Ranno, Laurent; Dumas-Bouchiat, Frédéric; Dempsey, Nora M.; Farge, Emmanuel

2017-01-01

Animal development consists of a cascade of tissue differentiation and shape change. Associated mechanical signals regulate tissue differentiation. Here we demonstrate that endogenous mechanical cues also trigger biochemical pathways, generating the active morphogenetic movements shaping animal development through a mechanotransductive cascade of Myo-II medio-apical stabilization. To mimic physiological tissue deformation with a cell scale resolution, liposomes containing magnetic nanoparticles are injected into embryonic epithelia and submitted to time-variable forces generated by a linear array of micrometric soft magnets. Periodic magnetically induced deformations quantitatively phenocopy the soft mechanical endogenous snail-dependent apex pulsations, rescue the medio-apical accumulation of Rok, Myo-II and subsequent mesoderm invagination lacking in sna mutants, in a Fog-dependent mechanotransductive process. Mesoderm invagination then activates Myo-II apical accumulation, in a similar Fog-dependent mechanotransductive process, which in turn initiates endoderm invagination. This reveals the existence of a highly dynamic self-inductive cascade of mesoderm and endoderm invaginations, regulated by mechano-induced medio-apical stabilization of Myo-II. PMID:28112149

Efficient differentiation of mouse embryonic stem cells into insulin-producing cells.

PubMed

Liu, Szu-Hsiu; Lee, Lain-Tze

2012-01-01

Embryonic stem (ES) cells are a potential source of a variety of differentiated cells for cell therapy, drug discovery, and toxicology screening. Here, we present an efficacy strategy for the differentiation of mouse ES cells into insulin-producing cells (IPCs) by a two-step differentiation protocol comprising of (i) the formation of definitive endoderm in monolayer culture by activin A, and (ii) this monolayer endoderm being induced to differentiate into IPCs by nicotinamide, insulin, and laminin. Differentiated cells can be obtained within approximately 7 days. The differentiation IPCs combined application of RT-PCR, ELISA, and immunofluorescence to characterize phenotypic and functional properties. In our study, we demonstrated that IPCs produced pancreatic transcription factors, endocrine progenitor marker, definitive endoderm, pancreatic β-cell markers, and Langerhans α and δ cells. The IPCs released insulin in a manner that was dose dependent upon the amount of glucose added. These techniques may be able to be applied to human ES cells, which would have very important ramifications for treating human disease.

Mechanotransductive cascade of Myo-II-dependent mesoderm and endoderm invaginations in embryo gastrulation

NASA Astrophysics Data System (ADS)

Mitrossilis, Démosthène; Röper, Jens-Christian; Le Roy, Damien; Driquez, Benjamin; Michel, Aude; Ménager, Christine; Shaw, Gorky; Le Denmat, Simon; Ranno, Laurent; Dumas-Bouchiat, Frédéric; Dempsey, Nora M.; Farge, Emmanuel

2017-01-01

Animal development consists of a cascade of tissue differentiation and shape change. Associated mechanical signals regulate tissue differentiation. Here we demonstrate that endogenous mechanical cues also trigger biochemical pathways, generating the active morphogenetic movements shaping animal development through a mechanotransductive cascade of Myo-II medio-apical stabilization. To mimic physiological tissue deformation with a cell scale resolution, liposomes containing magnetic nanoparticles are injected into embryonic epithelia and submitted to time-variable forces generated by a linear array of micrometric soft magnets. Periodic magnetically induced deformations quantitatively phenocopy the soft mechanical endogenous snail-dependent apex pulsations, rescue the medio-apical accumulation of Rok, Myo-II and subsequent mesoderm invagination lacking in sna mutants, in a Fog-dependent mechanotransductive process. Mesoderm invagination then activates Myo-II apical accumulation, in a similar Fog-dependent mechanotransductive process, which in turn initiates endoderm invagination. This reveals the existence of a highly dynamic self-inductive cascade of mesoderm and endoderm invaginations, regulated by mechano-induced medio-apical stabilization of Myo-II.

Human embryonic stem cell-derived pancreatic endoderm alleviates diabetic pathology and improves reproductive outcome in C57BL/KsJ-Lep(db/+) gestational diabetes mellitus mice.

PubMed

Xing, Baoheng; Wang, Lili; Li, Qin; Cao, Yalei; Dong, Xiujuan; Liang, Jun; Wu, Xiaohua

2015-07-01

Gestational diabetes mellitus is a condition commonly encountered during mid to late pregnancy with pathologic manifestations including hyperglycemia, hyperinsulinemia, insulin resistance, and fetal maldevelopment. The cause of gestational diabetes mellitus can be attributed to both genetic and environmental factors, hence complicating its diagnosis and treatment. Pancreatic progenitors derived from human embryonic stem cells were shown to be able to effectively treat diabetes in mice. In this study, we have developed a system of treating diabetes using human embryonic stem cell-derived pancreatic endoderm in a mouse model of gestational diabetes mellitus. Human embryonic stem cells were differentiated in vitro into pancreatic endoderm, which were then transplanted into db/+ mice suffering from gestational diabetes mellitus. The transplant greatly improved glucose metabolism and reproductive outcome of the females compared with the control groups. Our findings support the feasibility of using differentiated human embryonic stem cells for treating gestational diabetes mellitus patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Two different pathways for the transport of primitive and definitive blood cells from the yolk sac to the embryo in humans.

PubMed

Pereda, Jaime; Monge, Juan I; Niimi, Gen

2010-08-01

During the early human embryonic period nutrients and blood cells are temporarily provided by the extraembryonic yolk sac (YS). The YS before week six is involved not only in primitive but also in definitive erythropoiesis. While the destiny of primitive erythroid cells that fill the blood vessels of the YS is well known, the final destination of erythrocytes present in the endodermal vesicular system is unknown. In the present study we have investigated, step by step, the destiny of the erythrocytes present in the endodermal vesicles during the embryonic period. Twelve human YSs and their corresponding yolk stalks were analyzed between weeks 4 and 7 of embryonic age by light and scanning electron microscopy. It is shown that erythrocytes (according to their size and morphological features) located within the endodermal vesicles of the YS wall are pulled out through endodermal pits into the YS cavity, from where they reach the lumen of the primitive gut of the embryo through the vitelline duct, a temporary pathway communicating both compartments. During the study period no erythrocytes were seen within the embryo's vascular network where only primitive erythroblasts were identified. Our results indicate that the vitelline duct plays an important transient role as a pathway for the transport of nutrients and blood cells between the YS and the embryo before week five of embryonic development that ends just at the time when YS-embryo circulation becomes established. (c) 2010 Wiley-Liss, Inc.

Efficient femtosecond driven SOX 17 delivery into mouse embryonic stem cells: differentiation studies

NASA Astrophysics Data System (ADS)

Thobakgale, Lebogang; Manoto, Sello Lebohang; Lemboumba, Satuurnin Ombinda; Maaza, Malik; Mthunzi-Kufa, Patience

2017-02-01

Embryonic stem cells have great promise in regenerative medicine because of their ability to self-renew and differentiate into various cell types. Delivery of therapeutic genes into cells has already been achieved using of chemical agents and viral vectors with high transfection efficiencies. However, these methods have also been documented as toxic and in the latter case they can cause latent cell infections. In this study we use femtosecond laser pulses to optically deliver genetic material in mouse embryonic stem cells. Femtosecond laser pulses in contrast to the conventional approach, minimises the risk of unwanted side effects because photons are used to create transient pores on the membrane which allow free entry of molecules with no need for delivery agents. Using an Olympus microscope, fluorescence imaging of the samples post irradiation was performed and decreased expression of stage specific embryonic antigen one (SSEA-1) consistent with on-going cellular differentiation was observed. Our results also show that femtosecond laser pulses were effective in delivering SOX 17 plasmid DNA (pSOX17) which resulted in the differentiation of mouse embryonic stem cells into endoderm cells. We thus concluded that laser transfection of stem cells for the purpose of differentiation, holds potential for applications in tissue engineering as a method of generating new cell lines.

Functional Characterization of Cnidarian HCN Channels Points to an Early Evolution of Ih.

PubMed

Baker, Emma C; Layden, Michael J; van Rossum, Damian B; Kamel, Bishoy; Medina, Monica; Simpson, Eboni; Jegla, Timothy

2015-01-01

HCN channels play a unique role in bilaterian physiology as the only hyperpolarization-gated cation channels. Their voltage-gating is regulated by cyclic nucleotides and phosphatidylinositol 4,5-bisphosphate (PIP2). Activation of HCN channels provides the depolarizing current in response to hyperpolarization that is critical for intrinsic rhythmicity in neurons and the sinoatrial node. Additionally, HCN channels regulate dendritic excitability in a wide variety of neurons. Little is known about the early functional evolution of HCN channels, but the presence of HCN sequences in basal metazoan phyla and choanoflagellates, a protozoan sister group to the metazoans, indicate that the gene family predates metazoan emergence. We functionally characterized two HCN channel orthologs from Nematostella vectensis (Cnidaria, Anthozoa) to determine which properties of HCN channels were established prior to the emergence of bilaterians. We find Nematostella HCN channels share all the major functional features of bilaterian HCNs, including reversed voltage-dependence, activation by cAMP and PIP2, and block by extracellular Cs+. Thus bilaterian-like HCN channels were already present in the common parahoxozoan ancestor of bilaterians and cnidarians, at a time when the functional diversity of voltage-gated K+ channels was rapidly expanding. NvHCN1 and NvHCN2 are expressed broadly in planulae and in both the endoderm and ectoderm of juvenile polyps.

Cellular and molecular mechanisms coordinating pancreas development.

PubMed

Bastidas-Ponce, Aimée; Scheibner, Katharina; Lickert, Heiko; Bakhti, Mostafa

2017-08-15

The pancreas is an endoderm-derived glandular organ that participates in the regulation of systemic glucose metabolism and food digestion through the function of its endocrine and exocrine compartments, respectively. While intensive research has explored the signaling pathways and transcriptional programs that govern pancreas development, much remains to be discovered regarding the cellular processes that orchestrate pancreas morphogenesis. Here, we discuss the developmental mechanisms and principles that are known to underlie pancreas development, from induction and lineage formation to morphogenesis and organogenesis. Elucidating such principles will help to identify novel candidate disease genes and unravel the pathogenesis of pancreas-related diseases, such as diabetes, pancreatitis and cancer. © 2017. Published by The Company of Biologists Ltd.

Design of a nanocomposite substrate inducing adult stem cell assembly and progression toward an Epiblast-like or Primitive Endoderm-like phenotype via mechanotransduction.

PubMed

Morena, Francesco; Armentano, Ilaria; Montanucci, Pia; Argentati, Chiara; Fortunati, Elena; Montesano, Simona; Bicchi, Ilaria; Pescara, Teresa; Pennoni, Ilaria; Mattioli, Samantha; Torre, Luigi; Latterini, Loredana; Emiliani, Carla; Basta, Giuseppe; Calafiore, Riccardo; Kenny, Josè Maria; Martino, Sabata

2017-11-01

This work shows that the active interaction between human umbilical cord matrix stem cells and Poly (l-lactide)acid (PLLA) and PLLA/Multi Walled Carbon Nanotubes (MWCNTs) nanocomposite films results in the stem cell assembly as a spheroid conformation and affects the stem cell fate transition. We demonstrated that spheroids directly respond to a tunable surface and the bulk properties (electric, dielectric and thermal) of plain and nanocomposite PLLA films by triggering a mechanotransduction axis. This stepwise process starts from tethering of the cells' focal adhesion proteins to the surface, together with the adherens junctions between cells. Both complexes transmit traction forces to F-Actin stress fibres that link Filamin-A and Myosin-IIA proteins, generating a biological scaffold, with increased stiffening conformation from PLLA to PLLA/MWCNTs, and enable the nucleoskeleton proteins to boost chromatin reprogramming processes. Herein, the opposite expression of NANOG and GATA6 transcription factors, together with other lineage specification related proteins, steer spheroids toward an Epiblast-like or Primitive Endoderm-like lineage commitment, depending on the absence or presence of 1 wt% MWCNTs, respectively. This work represents a pioneering effort to create a stem cell/material interface that can model the stem cell fate transition under growth culture conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mesodermal retinoic acid signaling regulates endothelial cell coalescence in caudal pharyngeal arch artery vasculogenesis

PubMed Central

Li, Peng; Pashmforoush, Mohammad; Sucov, Henry M.

2011-01-01

Disruption of retinoic acid signaling causes a variety of pharyngeal arch artery and great vessel defects, as well as malformations in many other tissues, including those derived from the pharyngeal endoderm. Previous studies implied that arch artery defects in the context of defective RA signaling occur secondary to pharyngeal pouch segmentation defects, although this model has never been experimentally verified. In this study, we examined arch artery morphogenesis during mouse development, and the role of RA in this process. We show in normal embryos that the arch arteries form by vasculogenic differentiation of pharyngeal mesoderm. Using various genetic backgrounds and tissue-specific mutation approaches, we segregate pharyngeal arch artery and pharyngeal pouch defects in RA receptor mutants, and show that RA signal transduction only in pharyngeal mesoderm is required for arch artery formation. RA does not control pharyngeal mesodermal differentiation to endothelium, but instead promotes the aggregation of endothelial cells into nascent vessels. Expression of VE-cadherin was substantially reduced in RAR mutants, and this deficiency may underlie the arch artery defects. The consequences of disrupted mesodermal and endodermal RA signaling were restricted to the 4th and 6th arch arteries and to the 4th pharyngeal pouch, respectively, suggesting that different regulatory mechanisms control the formation of the more anterior arch arteries and pouches. PMID:22040871

Evidence for a role in growth and salt resistance of a plasma membrane H+-ATPase in the root endodermis

NASA Technical Reports Server (NTRS)

Vitart, V.; Baxter, I.; Doerner, P.; Harper, J. F.; Evans, M. L. (Principal Investigator)

2001-01-01

The plasma membrane of plant cells is energized by an electrochemical gradient produced by P-type H+-ATPases (proton pumps). These pumps are encoded by at least 12 genes in Arabidopsis. Here we provide evidence that isoform AHA4 contributes to solute transport through the root endodermis. AHA4 is expressed most strongly in the root endodermis and flowers, as suggested by promoter-GUS reporter assays. A disruption of this pump (aha4-1) was identified as a T-DNA insertion in the middle of the gene (after VFP(574)). Truncated aha4-1 transcripts accumulate to approximately 50% of the level observed for AHA4 mRNA in wild-type plants. Plants homozygous for aha4-1 (-/-) show a subtle reduction in root and shoot growth compared with wild-type plants when grown under normal conditions. However, a mutant phenotype is very clear in plants grown under salt stress (e.g., 75 or 110 mM NaCl). In leaves of mutant plants subjected to Na stress, the ratio of Na to K increased 4-5-fold. Interestingly, the aha4-1 mutation appears to be semidominant and was only partially complemented by the introduction of additional wild-type copies of AHA4. These results are consistent with the hypothesis that aha4-1 may produce a dominant negative protein or RNA that partially disrupts the activity of other pumps or functions in the root endodermal tissue, thereby compromising the function of this cell layer in controlling ion homeostasis and nutrient transport.

Thyroid Regeneration: Characterization of Clear Cells After Partial Thyroidectomy

PubMed Central

Ozaki, Takashi; Matsubara, Tsutomu; Seo, Daekwan; Okamoto, Minoru; Nagashima, Kunio; Sasaki, Yoshihito; Hayase, Suguru; Murata, Tsubasa; Liao, Xiao-Hui; Hanson, Jeffrey; Rodriguez-Canales, Jaime; Thorgeirsson, Snorri S.; Kakudo, Kennichi; Refetoff, Samuel

2012-01-01

Although having the capacity to grow in response to a stimulus that perturbs the pituitary-thyroid axis, the thyroid gland is considered not a regenerative organ. In this study, partial thyroidectomy (PTx) was used to produce a condition for thyroid regeneration. In the intact thyroid gland, the central areas of both lobes served as the proliferative centers where microfollicles, and bromodeoxyuridine (BrdU)-positive and/or C cells, were localized. Two weeks after PTx, the number of BrdU-positive cells and cells with clear or faintly eosinophilic cytoplasm were markedly increased in the central area and continuous to the cut edge. Clear cells were scant in the cytoplasm, as determined by electron microscopy; some retained the characteristics of calcitonin-producing C cells by having neuroendocrine granules, whereas others retained follicular cell-specific features, such as the juxtaposition to a lumen with microvilli. Some cells were BrdU-positive and expressed Foxa2, the definitive endoderm lineage marker. Serum TSH levels drastically changed due to the thyroidectomy-induced acute reduction in T4-generating tissue, resulting in a goitrogenesis setting. Microarray followed by pathway analysis revealed that the expression of genes involved in embryonic development and cancer was affected by PTx. The results suggest that both C cells and follicular cells may be altered by PTx to become immature cells or immature cells that might be derived from stem/progenitor cells on their way to differentiation into C cells or follicular cells. These immature clear cells may participate in the repair and/or regeneration of the thyroid gland. PMID:22454152

Dual Functions of ASCIZ in the DNA Base Damage Response and Pulmonary Organogenesis

PubMed Central

Tenis, Nora; Hammet, Andrew; Hewitt, Kimberly; Ng, Jane-Lee; McNees, Carolyn J.; Kozlov, Sergei V.; Oka, Hayato; Kobayashi, Masahiko; Conlan, Lindus A.; Cole, Timothy J.; Yamamoto, Ken-ichi; Taniguchi, Yoshihito; Takeda, Shunichi; Lavin, Martin F.; Heierhorst, Jörg

2010-01-01

Zn2+-finger proteins comprise one of the largest protein superfamilies with diverse biological functions. The ATM substrate Chk2-interacting Zn2+-finger protein (ASCIZ; also known as ATMIN and ZNF822) was originally linked to functions in the DNA base damage response and has also been proposed to be an essential cofactor of the ATM kinase. Here we show that absence of ASCIZ leads to p53-independent late-embryonic lethality in mice. Asciz-deficient primary fibroblasts exhibit increased sensitivity to DNA base damaging agents MMS and H2O2, but Asciz deletion or knock-down does not affect ATM levels and activation in mouse, chicken, or human cells. Unexpectedly, Asciz-deficient embryos also exhibit severe respiratory tract defects with complete pulmonary agenesis and severe tracheal atresia. Nkx2.1-expressing respiratory precursors are still specified in the absence of ASCIZ, but fail to segregate properly within the ventral foregut, and as a consequence lung buds never form and separation of the trachea from the oesophagus stalls early. Comparison of phenotypes suggests that ASCIZ functions between Wnt2-2b/ß-catenin and FGF10/FGF-receptor 2b signaling pathways in the mesodermal/endodermal crosstalk regulating early respiratory development. We also find that ASCIZ can activate expression of reporter genes via its SQ/TQ-cluster domain in vitro, suggesting that it may exert its developmental functions as a transcription factor. Altogether, the data indicate that, in addition to its role in the DNA base damage response, ASCIZ has separate developmental functions as an essential regulator of respiratory organogenesis. PMID:20975950

Molecular cloning and characterization of a steroidogenic enzyme, 17β-hydroxysteroid dehydrogenase type 14, from the stony coral Euphyllia ancora (Cnidaria, Anthozoa).

PubMed

Shikina, Shinya; Chung, Yi-Jou; Chiu, Yi-Ling; Huang, Yi-Jie; Lee, Yan-Horn; Chang, Ching-Fong

2016-03-01

Sex steroids play a fundamental role not only in reproduction but also in various other biological processes in vertebrates. Although the presence of sex steroids has been confirmed in cnidarians (e.g., coral, sea anemone, jellyfish, and hydra), which are basal metazoans, only a few studies to date have characterized steroidogenesis-related genes in cnidarians. Based on a transcriptomic analysis of the stony coral Euphyllia ancora, we identified the steroidogenic enzyme 17β-hydroxysteroid dehydrogenase type 14 (17beta-hsd 14), an oxidative enzyme that catalyzes the NAD(+)-dependent inactivation of estrogen/androgen (estradiol to estrone and testosterone to androstenedione) in mammals. Phylogenetic analysis showed that E. ancora 17beta-Hsd 14 (Ea17beta-Hsd 14) clusters with other animal 17beta-HSD 14s but not with other members of the 17beta-HSD family. Subsequent quantitative RT-PCR analysis revealed a lack of correlation of Ea17beta-hsd 14 transcript levels with the coral's reproductive cycle. In addition, Ea17beta-hsd 14 transcript and protein were detected in all tissues examined, such as the tentacles, mesenterial filaments, and gonads, at similar levels in both sexes, as determined by quantitative RT-PCR analysis and Western blotting with an anti-Ea17beta-Hsd 14 antibody. Immunohistochemical analysis revealed that Ea17beta-Hsd 14 is mainly distributed in the endodermal regions of the polyps, but the protein was also observed in all tissues examined. These results suggest that Ea17beta-Hsd 14 is involved in important functions that commonly occur in endodermal cells or has multiple functions in different tissues. Our data provide information for comparison with advanced animals as well as insight into the evolution of steroidogenesis-related genes in metazoans. Copyright © 2016 Elsevier Inc. All rights reserved.

Spectroscopic signature of mouse embryonic stem cell-derived hepatocytes using synchrotron Fourier transform infrared microspectroscopy

NASA Astrophysics Data System (ADS)

Thumanu, Kanjana; Tanthanuch, Waraporn; Ye, Danna; Sangmalee, Anawat; Lorthongpanich, Chanchao; Parnpai, Rangsun; Heraud, Philip

2011-05-01

Stem cell-based therapy for liver regeneration has been proposed to overcome the persistent shortage in the supply of suitable donor organs. A requirement for this to succeed is to find a rapid method to detect functional hepatocytes, differentiated from embryonic stem cells. We propose Fourier transform infrared (FTIR) microspectroscopy as a versatile method to identify the early and last stages of the differentiation process leading to the formation of hepatocytes. Using synchrotron-FTIR microspectroscopy, the means of identifying hepatocytes at the single-cell level is possible and explored. Principal component analysis and subsequent partial least-squares (PLS) discriminant analysis is applied to distinguish endoderm induction from hepatic progenitor cells and matured hepatocyte-like cells. The data are well modeled by PLS with endoderm induction, hepatic progenitor cells, and mature hepatocyte-like cells able to be discriminated with very high sensitivity and specificity. This method provides a practical tool to monitor endoderm induction and has the potential to be applied for quality control of cell differentiation leading to hepatocyte formation.

Evolution of the hypoxia-sensitive cells involved in amniote respiratory reflexes

PubMed Central

Hockman, Dorit; Burns, Alan J; Schlosser, Gerhard; Gates, Keith P; Jevans, Benjamin; Mongera, Alessandro; Fisher, Shannon; Unlu, Gokhan; Knapik, Ela W; Kaufman, Charles K; Mosimann, Christian; Zon, Leonard I; Lancman, Joseph J; Dong, P Duc S; Lickert, Heiko; Tucker, Abigail S; Baker, Clare V H

2017-01-01

The evolutionary origins of the hypoxia-sensitive cells that trigger amniote respiratory reflexes – carotid body glomus cells, and ‘pulmonary neuroendocrine cells’ (PNECs) - are obscure. Homology has been proposed between glomus cells, which are neural crest-derived, and the hypoxia-sensitive ‘neuroepithelial cells’ (NECs) of fish gills, whose embryonic origin is unknown. NECs have also been likened to PNECs, which differentiate in situ within lung airway epithelia. Using genetic lineage-tracing and neural crest-deficient mutants in zebrafish, and physical fate-mapping in frog and lamprey, we find that NECs are not neural crest-derived, but endoderm-derived, like PNECs, whose endodermal origin we confirm. We discover neural crest-derived catecholaminergic cells associated with zebrafish pharyngeal arch blood vessels, and propose a new model for amniote hypoxia-sensitive cell evolution: endoderm-derived NECs were retained as PNECs, while the carotid body evolved via the aggregation of neural crest-derived catecholaminergic (chromaffin) cells already associated with blood vessels in anamniote pharyngeal arches. DOI: http://dx.doi.org/10.7554/eLife.21231.001 PMID:28387645

The retinoic acid signaling pathway regulates anterior/posterior patterning in the nerve cord and pharynx of amphioxus, a chordate lacking neural crest.

PubMed

Escriva, Hector; Holland, Nicholas D; Gronemeyer, Hinrich; Laudet, Vincent; Holland, Linda Z

2002-06-01

Amphioxus, the closest living invertebrate relative of the vertebrates, has a notochord, segmental axial musculature, pharyngeal gill slits and dorsal hollow nerve cord, but lacks neural crest. In amphioxus, as in vertebrates, exogenous retinoic acid (RA) posteriorizes the embryo. The mouth and gill slits never form, AmphiPax1, which is normally downregulated where gill slits form, remains upregulated and AmphiHox1 expression shifts anteriorly in the nerve cord. To dissect the role of RA signaling in patterning chordate embryos, we have cloned the single retinoic acid receptor (AmphiRAR), retinoid X receptor (AmphiRXR) and an orphan receptor (AmphiTR2/4) from amphioxus. AmphiTR2/4 inhibits AmphiRAR-AmphiRXR-mediated transactivation in the presence of RA by competing for DR5 or IR7 retinoic acid response elements (RAREs). The 5' untranslated region of AmphiTR2/4 contains an IR7 element, suggesting possible auto- and RA-regulation. The patterns of AmphiTR2/4 and AmphiRAR expression during embryogenesis are largely complementary: AmphiTR2/4 is strongly expressed in the cerebral vesicle (homologous to the diencephalon plus anterior midbrain), while AmphiRAR expression is high in the equivalent of the hindbrain and spinal cord. Similarly, while AmphiTR2/4 is expressed most strongly in the anterior and posterior thirds of the endoderm, the highest AmphiRAR expression is in the middle third. Expression of AmphiRAR is upregulated by exogenous RA and completely downregulated by the RA antagonist BMS009. Moreover, BMS009 expands the pharynx posteriorly; the first three gill slit primordia are elongated and shifted posteriorly, but do not penetrate, and additional, non-penetrating gill slit primordia are induced. Thus, in an organism without neural crest, initiation and penetration of gill slits appear to be separate events mediated by distinct levels of RA signaling in the pharyngeal endoderm. Although these compounds have little effect on levels of AmphiTR2/4 expression, RA shifts pharyngeal expression of AmphiTR2/4 anteriorly, while BMS009 extends it posteriorly. Collectively, our results suggest a model for anteroposterior patterning of the amphioxus nerve cord and pharynx, which is probably applicable to vertebrates as well, in which a low anterior level of AmphiRAR (caused, at least in part, by competitive inhibition by AmphiTR2/4) is necessary for patterning the forebrain and formation of gill slits, the posterior extent of both being set by a sharp increase in the level of AmphiRAR. Supplemental data available on-line

The retinoic acid signaling pathway regulates anterior/posterior patterning in the nerve cord and pharynx of amphioxus, a chordate lacking neural crest

NASA Technical Reports Server (NTRS)

Escriva, Hector; Holland, Nicholas D.; Gronemeyer, Hinrich; Laudet, Vincent; Holland, Linda Z.

2002-01-01

Amphioxus, the closest living invertebrate relative of the vertebrates, has a notochord, segmental axial musculature, pharyngeal gill slits and dorsal hollow nerve cord, but lacks neural crest. In amphioxus, as in vertebrates, exogenous retinoic acid (RA) posteriorizes the embryo. The mouth and gill slits never form, AmphiPax1, which is normally downregulated where gill slits form, remains upregulated and AmphiHox1 expression shifts anteriorly in the nerve cord. To dissect the role of RA signaling in patterning chordate embryos, we have cloned the single retinoic acid receptor (AmphiRAR), retinoid X receptor (AmphiRXR) and an orphan receptor (AmphiTR2/4) from amphioxus. AmphiTR2/4 inhibits AmphiRAR-AmphiRXR-mediated transactivation in the presence of RA by competing for DR5 or IR7 retinoic acid response elements (RAREs). The 5' untranslated region of AmphiTR2/4 contains an IR7 element, suggesting possible auto- and RA-regulation. The patterns of AmphiTR2/4 and AmphiRAR expression during embryogenesis are largely complementary: AmphiTR2/4 is strongly expressed in the cerebral vesicle (homologous to the diencephalon plus anterior midbrain), while AmphiRAR expression is high in the equivalent of the hindbrain and spinal cord. Similarly, while AmphiTR2/4 is expressed most strongly in the anterior and posterior thirds of the endoderm, the highest AmphiRAR expression is in the middle third. Expression of AmphiRAR is upregulated by exogenous RA and completely downregulated by the RA antagonist BMS009. Moreover, BMS009 expands the pharynx posteriorly; the first three gill slit primordia are elongated and shifted posteriorly, but do not penetrate, and additional, non-penetrating gill slit primordia are induced. Thus, in an organism without neural crest, initiation and penetration of gill slits appear to be separate events mediated by distinct levels of RA signaling in the pharyngeal endoderm. Although these compounds have little effect on levels of AmphiTR2/4 expression, RA shifts pharyngeal expression of AmphiTR2/4 anteriorly, while BMS009 extends it posteriorly. Collectively, our results suggest a model for anteroposterior patterning of the amphioxus nerve cord and pharynx, which is probably applicable to vertebrates as well, in which a low anterior level of AmphiRAR (caused, at least in part, by competitive inhibition by AmphiTR2/4) is necessary for patterning the forebrain and formation of gill slits, the posterior extent of both being set by a sharp increase in the level of AmphiRAR. Supplemental data available on-line.

Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

PubMed

Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

2011-01-15

Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that the neural crest is a critical regulator of beta cell development on two levels: by negatively regulating beta cell proliferation and by promoting beta cell maturation. Copyright © 2010 Elsevier Inc. All rights reserved.

Glucose responsive insulin production from human embryonic germ (EG) cell derivatives.

PubMed

Clark, Gregory O; Yochem, Robert L; Axelman, Joyce; Sheets, Timothy P; Kaczorowski, David J; Shamblott, Michael J

2007-05-11

Type 1 diabetes mellitus subjects millions to a daily burden of disease management, life threatening hypoglycemia and long-term complications such as retinopathy, nephropathy, heart disease, and stroke. Cell transplantation therapies providing a glucose-regulated supply of insulin have been implemented clinically, but are limited by safety, efficacy and supply considerations. Stem cells promise a plentiful and flexible source of cells for transplantation therapies. Here, we show that cells derived from human embryonic germ (EG) cells express markers of definitive endoderm, pancreatic and beta-cell development, glucose sensing, and production of mature insulin. These cells integrate functions necessary for glucose responsive regulation of preproinsulin mRNA and expression of insulin C-peptide in vitro. Following transplantation into mice, cells become insulin and C-peptide immunoreactive and produce plasma C-peptide in response to glucose. These findings suggest that EG cell derivatives may eventually serve as a source of insulin producing cells for the treatment of diabetes.

Specifying pancreatic endocrine cell fates.

PubMed

Collombat, Patrick; Hecksher-Sørensen, Jacob; Serup, Palle; Mansouri, Ahmed

2006-07-01

Cell replacement therapy could represent an attractive alternative to insulin injections for the treatment of diabetes. However, this approach requires a thorough understanding of the molecular switches controlling the specification of the different pancreatic cell-types in vivo. These are derived from an apparently identical pool of cells originating from the early gut endoderm, which are successively specified towards the pancreatic, endocrine, and hormone-expressing cell lineages. Numerous studies have outlined the crucial roles exerted by transcription factors in promoting the cell destiny, defining the cell identity and maintaining a particular cell fate. This review focuses on the mechanisms regulating the morphogenesis of the pancreas with particular emphasis on recent findings concerning the transcription factor hierarchy orchestrating endocrine cell fate allocation.

Expression and immunolocalisation of the endocytic receptors megalin and cubilin in the human yolk sac and placenta across gestation☆

PubMed Central

Burke, K.A.; Jauniaux, E.; Burton, G.J.; Cindrova-Davies, T.

2013-01-01

Megalin and cubilin are multifunctional endocytic receptors associated with many transporting epithelia. They play an essential role in transport of nutrients through the visceral yolk sac of rodents during embryogenesis. Here, we immunolocalise them to the endodermal layer of the human yolk sac, and to the syncytiotrophoblast and cytotrophoblast cells of placental villi. In villi, the protein level of both receptors increased with gestation. The mRNA for megalin remained constant, while that encoding cubilin increased with gestation. These results suggest megalin and cubilin may be important in human maternal–fetal transfer, and that they increase across gestation to facilitate this function. PMID:23978537

SGR9, a RING type E3 ligase, modulates amyloplast dynamics important for gravity sensing.

NASA Astrophysics Data System (ADS)

Morita, Miyo T.; Nakamura, Moritaka; Tasaka, Masao

Gravitropism is triggered when the directional change of gravity is sensed in the specific cells, called statocytes. In higher plants, statocytes contain sinking heavier amyloplasts which are particular plastids accumulating starch granules. The displacement of amyloplasts within the statocytes is thought to be the initial event of gravity perception. We have demonstrated that endodermal cells are most likely to be the statocytes in Arabidop-sis shoots. Live cell imaging of the endodermal cell of stem has shown that most amyloplasts are sediment to the direction of gravity but they are not static. Several amyloplasts move dynamically in an actin filament (F-actin) dependent manner. In the presence of actin poly-merization inhibitor, all amyloplasts become static and sediment to the direction of gravity. In addition, stems treated with the inhibitor can exhibit gravitropism. These results suggest that F-actin-dependent dynamic movement of amyloplasts is not essential for gravity sensing. sgr (shoot gravitropism) 9 mutant exhibits greatly reduced shoot gravitropism. In endodermal cells of sgr9, dynamic amyloplast movement was predominantly observed and amyloplasts did not sediment to the direction of gravity. Interestingly, inhibition of actin polymerization re-stored both gravitropism and amyloplast sedimentation in sgr9. The SGR9 encodes a novel RING finger protein, which is localized to amyloplasts in endodermal cells. SGR9 showed ubiq-uitin E3 ligase activity in vitro. Together with live cell imaging of amyloplasts and F-actin, our data suggest that SGR9 modulate interaction between amyloplasts and F-actin on amylo-plasts. SGR9 positively act on amyloplasts sedimentation, probably by releasing amyloplasts from F-actin. SGR9 that is localized to amyloplast, possibly degrades unknown substrates by its E3 ligase activity, and this might promote release of amyloplasts from F-actin.

Efficient generation of functional pancreatic β-cells from human induced pluripotent stem cells.

PubMed

Yabe, Shigeharu G; Fukuda, Satsuki; Takeda, Fujie; Nashiro, Kiyoko; Shimoda, Masayuki; Okochi, Hitoshi

2017-02-01

Insulin-secreting cells have been generated from human embryonic or induced pluripotent stem cells (iPSCs) by mimicking developmental processes. However, these cells do not always secrete glucose-responsive insulin, one of the most important characteristics of pancreatic β-cells. We focused on the importance of endodermal differentiation from human iPSCs in order to obtain functional pancreatic β-cells. A six-stage protocol was established for the differentiation of human iPSCs to pancreatic β-cells using defined culture media without feeders or serum. The effects of CHIR99021, a selective glycogen synthase kinase-3β inhibitor, were examined in the presence of fibroblast growth factor 2, activin, and bone morphogenetic protein 4 (FAB) during definitive endodermal induction by immunostaining for SRY (sex determining region Y)-box 17 (SOX17) and Forkhead box protein A2 (FOXA2). Insulin secretion was compared between the last stage of monolayer culture and spheroid culture conditions. Cultured cells were transplanted under kidney capsules of streptozotocin-diabetic non-obese diabetic-severe combined immunodeficiency mice, and blood glucose levels were measured once a week. Immunohistochemical analyses were performed 4 and 12 weeks after transplantation. Addition of CHIR99021 (3 μmol/L) in the presence of FAB for 2 days improved endodermal cell viability, maintaining the high SOX17-positive rate. Spheroid formation after the endocrine progenitor stage showed more efficient insulin secretion than did monolayer culture. After cell transplantation, diabetic mice had lower blood glucose levels, and islet-like structures were detected in vivo. Functional pancreatic β-cells were generated from human iPSCs. Induction of definitive endoderm and spheroid formation may be key steps for producing these cells. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Raman Spectroscopic Imaging of the Whole Ciona intestinalis Embryo during Development

PubMed Central

Nakamura, Mitsuru J.; Hotta, Kohji; Oka, Kotaro

2013-01-01

Intracellular composition and the distribution of bio-molecules play central roles in the specification of cell fates and morphogenesis during embryogenesis. Consequently, investigation of changes in the expression and distribution of bio-molecules, especially mRNAs and proteins, is an important challenge in developmental biology. Raman spectroscopic imaging, a non-invasive and label-free technique, allows simultaneous imaging of the intracellular composition and distribution of multiple bio-molecules. In this study, we explored the application of Raman spectroscopic imaging in the whole Ciona intestinalis embryo during development. Analysis of Raman spectra scattered from C. intestinalis embryos revealed a number of localized patterns of high Raman intensity within the embryo. Based on the observed distribution of bio-molecules, we succeeded in identifying the location and structure of differentiated muscle and endoderm within the whole embryo, up to the tailbud stage, in a label-free manner. Furthermore, during cell differentiation, we detected significant differences in cell state between muscle/endoderm daughter cells and daughter cells with other fates that had divided from the same mother cells; this was achieved by focusing on the Raman intensity of single Raman bands at 1002 or 1526 cm−1, respectively. This study reports the first application of Raman spectroscopic imaging to the study of identifying and characterizing differentiating tissues in a whole chordate embryo. Our results suggest that Raman spectroscopic imaging is a feasible label-free technique for investigating the developmental process of the whole embryo of C. intestinalis. PMID:23977129

Expression of Ciona intestinalis Variable Region-Containing Chitin-Binding Proteins during Development of the Gastrointestinal Tract and Their Role in Host-Microbe Interactions

PubMed Central

Liberti, Assunta; Melillo, Daniela; Zucchetti, Ivana; Natale, Lenina; Dishaw, Larry J.; Litman, Gary W.; De Santis, Rosaria; Pinto, Maria Rosaria

2014-01-01

Variable region-containing chitin-binding proteins (VCBPs) are secreted, immune-type molecules that have been described in both amphioxus, a cephalochordate, and sea squirt, Ciona intestinalis, a urochordate. In adult Ciona, VCBP-A, -B and -C are expressed in hemocytes and the cells of the gastrointestinal tract. VCBP-C binds bacteria in the stomach lumen and functions as an opsonin in vitro. In the present paper the expression of VCBPs has been characterized during development using in situ hybridization, immunohistochemical staining and quantitative polymerase chain reaction (qPCR) technologies. The expression of VCBP-A and -C is detected first in discrete areas of larva endoderm and becomes progressively localized during differentiation in the stomach and intestine, marking the development of gut tracts. In “small adults” (1–2 cm juveniles) expression of VCBP-C persists and VCBP-A gradually diminishes, ultimately replaced by expression of VCBP-B. The expression of VCBP-A and -C in stage 7–8 juveniles, at which point animals have already started feeding, is influenced significantly by challenge with either Gram-positive or -negative bacteria. A potential role for VCBPs in gut-microbiota interactions and homeostasis is indicated. PMID:24788831

Morphogenesis in sea urchin embryos: linking cellular events to gene regulatory network states

PubMed Central

Lyons, Deidre; Kaltenbach, Stacy; McClay, David R.

2013-01-01

Gastrulation in the sea urchin begins with ingression of the primary mesenchyme cells (PMCs) at the vegetal pole of the embryo. After entering the blastocoel the PMCs migrate, form a syncitium, and synthesize the skeleton of the embryo. Several hours after the PMCs ingress the vegetal plate buckles to initiate invagination of the archenteron. That morphogenetic process occurs in several steps. The non-skeletogenic cells produce the initial inbending of the vegetal plate. Endoderm cells then rearrange and extend the length of the gut across the blastocoel to a target near the animal pole. Finally, cells that will form part of the midgut and hindgut are added to complete gastrulation. Later, the stomodeum invaginates from the oral ectoderm and fuses with the foregut to complete the archenteron. In advance of, and during these morphogenetic events an increasingly complex gene regulatory network controls the specification and the cell biological events that conduct the gastrulation movements. PMID:23801438

Molecular-clinical correlation in a family with a novel heteroplasmic Leigh syndrome missense mutation in the mitochondrial cytochrome c oxidase III gene.

PubMed

Mkaouar-Rebai, Emna; Ellouze, Emna; Chamkha, Imen; Kammoun, Fatma; Triki, Chahnez; Fakhfakh, Faiza

2011-01-01

Cytochrome c oxidase is an essential component of the mitochondrial respiratory chain that catalyzes the reduction of molecular oxygen by reduced cytochrome c. In this study, the authors report the second mutation associated with Leigh syndrome in the blood and buccal mucosa of 2 affected members of a Tunisian family. It was a novel heteroplasmic missense mitochondrial mutation at nucleotide 9478 in the gene specifying subunit III of cytochrome c oxidase substituting the valine at position 91 to alanine in a highly conserved amino acid. It was found with a high mutant load in tissues derived from endoderm (buccal mucosa) and mesoderm (blood). However, it was nearly absent in tissue derived from ectoderm (hair follicles). It was absent in 120 healthy controls, and PolyPhen analysis showed that the hydropathy index changed from +1.276 to +0.242, and the number of structures of the 3D protein decreased from 39 to 32.

A Rapid CRISPR/Cas-based Mutagenesis Assay in Zebrafish for Identification of Genes Involved in Thyroid Morphogenesis and Function.

PubMed

Trubiroha, A; Gillotay, P; Giusti, N; Gacquer, D; Libert, F; Lefort, A; Haerlingen, B; De Deken, X; Opitz, R; Costagliola, S

2018-04-04

The foregut endoderm gives rise to several organs including liver, pancreas, lung and thyroid with important roles in human physiology. Understanding which genes and signalling pathways regulate their development is crucial for understanding developmental disorders as well as diseases in adulthood. We exploited unique advantages of the zebrafish model to develop a rapid and scalable CRISPR/Cas-based mutagenesis strategy aiming at the identification of genes involved in morphogenesis and function of the thyroid. Core elements of the mutagenesis assay comprise bi-allelic gene invalidation in somatic mutants, a non-invasive monitoring of thyroid development in live transgenic fish, complementary analyses of thyroid function in fixed specimens and quantitative analyses of mutagenesis efficiency by Illumina sequencing of individual fish. We successfully validated our mutagenesis-phenotyping strategy in experiments targeting genes with known functions in early thyroid morphogenesis (pax2a, nkx2.4b) and thyroid functional differentiation (duox, duoxa, tshr). We also demonstrate that duox and duoxa crispants phenocopy thyroid phenotypes previously observed in human patients with bi-allelic DUOX2 and DUOXA2 mutations. The proposed combination of efficient mutagenesis protocols, rapid non-invasive phenotyping and sensitive genotyping holds great potential to systematically characterize the function of larger candidate gene panels during thyroid development and is applicable to other organs and tissues.

Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.

PubMed Central

Cary, N. R.; Fox, B.; Wright, D. J.; Cutler, S. J.; Shapiro, L. M.; Grace, A. A.

1990-01-01

A fatal case of Lyme carditis occurring in a Suffolk farmworker is reported. Post-mortem examination of the heart showed pericarditis, focal myocarditis and prominent endocardial and interstitial fibrosis. The additional finding of endodermal heterotopia ('mesothelioma') of the atrioventricular node raises the possibility that this could also be related to Lyme infection and account for the relatively frequent occurrence of atrioventricular block in this condition. Lyme disease should always be considered in a case of atrioventricular block, particularly in a young patient from a rural area. The heart block tends to improve and therefore only temporary pacing may be required. Images Figure 1 Figure 2 Figure 3 PMID:2349186

The origin of mesoderm in phoronids

NASA Technical Reports Server (NTRS)

Freeman, Gary; Martindale, Mark Q.

2002-01-01

Descriptive studies of phoronid development have concluded that the mesoderm of these animals originates from the endoderm during gastrulation. This interpretation has been tested by labeling one blastomere of 4- through 16-cell embryos and examining the position and germ layers occupied by the labeled clones of cells in the larva. No 2 injections gave rise to identical clones of cells, suggesting that the cleavage program does not generate cells of unique identity and that cell fates are established at later developmental time points. In many cases, a relatively large sector composed of ectodermal cells was labeled. When these labeled cells were adjacent to the mouth or anus of the larva, muscle and mesenchyme cells originated from the labeled clones. Under these circumstances, nerve cells also originated from these labeled sectors. These labeling studies also showed that endodermal cells can give rise to mesodermal and neural cells. These results suggest that nerve and muscle cells are induced to form at ectodermal-endodermal boundaries from both germ layers. These marking experiments also confirmed the observation that nerve cells originate both from the apical organ and the trunk region and show for the first time that the intestine originates by ingression of posterior ectoderm.

RCN1/OsABCG5, an ATP-binding cassette (ABC) transporter, is required for hypodermal suberization of roots in rice (Oryza sativa).

PubMed

Shiono, Katsuhiro; Ando, Miho; Nishiuchi, Shunsaku; Takahashi, Hirokazu; Watanabe, Kohtaro; Nakamura, Motoaki; Matsuo, Yuichi; Yasuno, Naoko; Yamanouchi, Utako; Fujimoto, Masaru; Takanashi, Hideki; Ranathunge, Kosala; Franke, Rochus B; Shitan, Nobukazu; Nishizawa, Naoko K; Takamure, Itsuro; Yano, Masahiro; Tsutsumi, Nobuhiro; Schreiber, Lukas; Yazaki, Kazufumi; Nakazono, Mikio; Kato, Kiyoaki

2014-10-01

Suberin is a complex polymer composed of aliphatic and phenolic compounds. It is a constituent of apoplastic plant interfaces. In many plant species, including rice (Oryza sativa), the hypodermis in the outer part of roots forms a suberized cell wall (the Casparian strip and/or suberin lamellae), which inhibits the flow of water and ions and protects against pathogens. To date, there is no genetic evidence that suberin forms an apoplastic transport barrier in the hypodermis. We discovered that a rice reduced culm number1 (rcn1) mutant could not develop roots longer than 100 mm in waterlogged soil. The mutated gene encoded an ATP-binding cassette (ABC) transporter named RCN1/OsABCG5. RCN1/OsABCG5 gene expression in the wild type was increased in most hypodermal and some endodermal roots cells under stagnant deoxygenated conditions. A GFP-RCN1/OsABCG5 fusion protein localized at the plasma membrane of the wild type. Under stagnant deoxygenated conditions, well suberized hypodermis developed in wild types but not in rcn1 mutants. Under stagnant deoxygenated conditions, apoplastic tracers (periodic acid and berberine) were blocked at the hypodermis in the wild type but not in rcn1, indicating that the apoplastic barrier in the mutant was impaired. The amount of the major aliphatic suberin monomers originating from C(28) and C(30) fatty acids or ω-OH fatty acids was much lower in rcn1 than in the wild type. These findings suggest that RCN1/OsABCG5 has a role in the suberization of the hypodermis of rice roots, which contributes to formation of the apoplastic barrier. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Temporal Control of Gene Expression by Combining Electroporation and the Tetracycline Inducible Systems in Vertebrate Embryos

NASA Astrophysics Data System (ADS)

Dubrulle, Julien; Pourquié, Olivier

The electroporation technique has revolutionized vertebrate embryology. It has greatly contributed to our understanding of how genes and proteins can interact and regulate various aspects of vertebrate development in the last decade. This technique provides an efficient way to transfect embryonic cells in vivo with exogenous DNA by cre ating transient holes in the plasma membrane with short, squared electric pulses of low voltage (Itasaki et al., 1999; Momose et al., 1999; Muramatsu et al., 1997; Nakamura et al., 2004; Ogura, 2002). It has been particularly well-developed in the chick model since the large size of the embryo and its easy accessibility enables to target specific tissues with great precision. With the electroporation, it is possible to precisely choose which type of cells to transfect by performing a local injection of DNA close to the cells of interest, followed by the application of a small current through the targeted area. To date, all three germ layers — endoderm, mesoderm and ectoderm — as well as an increasing number of differentiated structures have been efficiently transfected (Dubrulle et al., 2001; Grapin-Botton et al., 2001; Itasaki et al., 1999; Luo and Redies, 2005; Scaal et al., 2004) and the continuous improvement in electrode design makes it even possible to aim at sub-populations of cells within a given tissue. In addition to this spatial precision, the technique also allows great temporal precision; any stage of development, ranging from pre-gastrulation stage to adulthood can be reached as long as the cells or structures are accessible for local DNA injection and electrode placement (Bigey et al., 2002; Iimura and Pourquie, 2006).

Mediator Med23 deficiency enhances neural differentiation of murine embryonic stem cells through modulating BMP signaling.

PubMed

Zhu, Wanqu; Yao, Xiao; Liang, Yan; Liang, Dan; Song, Lu; Jing, Naihe; Li, Jinsong; Wang, Gang

2015-02-01

Unraveling the mechanisms underlying early neural differentiation of embryonic stem cells (ESCs) is crucial to developing cell-based therapies of neurodegenerative diseases. Neural fate acquisition is proposed to be controlled by a 'default' mechanism, for which the molecular regulation is not well understood. In this study, we investigated the functional roles of Mediator Med23 in pluripotency and lineage commitment of murine ESCs. Unexpectedly, we found that, despite the largely unchanged pluripotency and self-renewal of ESCs, Med23 depletion rendered the cells prone to neural differentiation in different differentiation assays. Knockdown of two other Mediator subunits, Med1 and Med15, did not alter the neural differentiation of ESCs. Med15 knockdown selectively inhibited endoderm differentiation, suggesting the specificity of cell fate control by distinctive Mediator subunits. Gene profiling revealed that Med23 depletion attenuated BMP signaling in ESCs. Mechanistically, MED23 modulated Bmp4 expression by controlling the activity of ETS1, which is involved in Bmp4 promoter-enhancer communication. Interestingly, med23 knockdown in zebrafish embryos also enhanced neural development at early embryogenesis, which could be reversed by co-injection of bmp4 mRNA. Taken together, our study reveals an intrinsic, restrictive role of MED23 in early neural development, thus providing new molecular insights for neural fate determination. © 2015. Published by The Company of Biologists Ltd.

Mechanism-based facilitated maturation of human pluripotent stem cell-derived cardiomyocytes

PubMed Central

Lieu, Deborah K.; Fu, Ji-Dong; Chiamvimonvat, Nipavan; Chan Tung, Kelvin W.; McNerney, Gregory P.; Huser, Thomas; Keller, Gordon; Kong, Chi-Wing

2013-01-01

Background Human embryonic stem cells (hESCs) can be efficiently and reproducibly directed into cardiomyocytes (CMs) using stage-specific induction protocols. However, their functional properties and suitability for clinical and other applications have not been evaluated. Methods and Results Here we showed that CMs derived from multiple pluripotent human stem cell lines (hESC: H1, HES2) and types (induced pluripotent stem cell or iPSC) using different in vitro differentiation protocols (embryoid body formation, endodermal induction, directed differentiation) commonly displayed immature, pro-arrhythmic action potential (AP) properties such as high-degree of automaticity, depolarized resting membrane potential (RMP), Phase 4- depolarization and delayed after-depolarization (DAD). Among the panoply of sarcolemmal ionic currents investigated (INa+/ICaL2+/IKr+/INCX+/If+/Ito+/IK1-/IKs-), we pinpointed the lack of the Kir2.1-encoded inwardly rectifying K+ current (IK1) as the single mechanistic contributor to the observed immature electrophysiological properties in hESC-CMs. Forced expression of Kir2.1 in hESC-CMs led to robust expression of Ba2+-sensitive IK1 and more importantly, completely ablated all the pro-arrhythmic AP traits, rendering the electrophysiological phenotype indistinguishable from the adult counterparts. These results provided the first link of a complex developmentally arrested phenotype to a major effector gene, and importantly, further led us to develop a biomimetic culturing strategy for enhancing maturation. Conclusions By providing the environmental cues that are missing in conventional culturing method, this approach did not require any genetic or pharmacological interventions. Our findings can facilitate clinical applications, drug discovery and cardiotoxicity screening by improving the yield, safety and efficacy of derived CMs. PMID:23392582

[The characters and specific features of new human embryonic stem cells lines].

PubMed

Krylova, T A; Kol'tsova, A M; Zenin, V V; Gordeeva, O F; Musorina, A S; Goriachaia, T S; Shlykova, S A; Kamenetskaia, Iu K; Pinaev, G P; Polianskaia, G G

2009-01-01

Four continuous human embryonic stem cell lines (SC1, SC2, SC3 and SC4), derived from the blastocysts has been described. The cell lines were cultivated on mitotically inactivated human feeder cells. The cell lines SC1 and SC2 have passed through 150 population doublings and the cell lines SC3 and SC4 -- near 120 populations doublings, which exceeds Hayflick limit sufficiently. These cell lines maintain high activity of alkaline phosphatase, expression of transcription factor OCT-4 and cell surface antigens (SSEA-4, TRA-1-60 and TRA-1-81), confirming their ESC status and human specificity. Immunofluorescent detection of antigens, characteristic of ectoderm, endoderm and mesoderm confirms the ability of these cells to retain their pluripotency under in vitro condition. PCR analysis revealed expression of six genes specific for pluripotent cells (OCT-4, NANOG, DPPA3/STELLA, TDGF/CRIPTO and LEFTYA). Correlation between the level of proliferative activity and the character of DNA-bound fluorescent staining was found. Fluorescent dyes, Hoechst 33342 and PI, produced diffuse staining of the nuclei in slowly proliferating cells of the SC1 and SC2 lines. In contrast, in actively proliferating cells of the SC3 and SC4 lines, the clear staining of the nuclei was observed. Upon changing the cultivation condition, proliferative activity of SC3 and SC4 lines decreased and became similar to that of SC1 and SC2 lines. The character of the fluorescent staining of all these lines was also shown to be similar. These results show that quality of the fluorescent staining with Hoechst 33342 and PI reflects the level of proliferation. Possible causes and mechanisms of this feature of human ESC are discussed.

Systematic Review to Compare Urothelium Differentiation with Urethral Epithelium Differentiation in Fetal Development, as a Basis for Tissue Engineering of the Male Urethra.

PubMed

de Graaf, Petra; van der Linde, E Martine; Rosier, Peter F W M; Izeta, Ander; Sievert, Karl-Dietrich; Bosch, J L H Ruud; de Kort, Laetitia M O

2017-06-01

Tissue-engineered (TE) urethra is desirable in men with urethral disease (stricture or hypospadias) and shortage of local tissue. Although ideally a TE graft would contain urethral epithelium cells, currently, bladder epithelium (urothelium) is widely used, but morphologically different. Understanding the differences and similarities of urothelium and urethral epithelium could help design a protocol for in vitro generation of urethral epithelium to be used in TE grafts for the urethra. To understand the development toward urethral epithelium or urothelium to improve TE of the urethra. A literature search was done following PRISMA guidelines. Articles describing urethral epithelium and bladder urothelium development in laboratory animals and humans were selected. Twenty-nine studies on development of urethral epithelium and 29 studies on development of urothelium were included. Both tissue linings derive from endoderm and although adult urothelium and urethral epithelium are characterized by different gene expression profiles, the signaling pathways underlying their development are similar, including Shh, BMP, Wnt, and FGF. The progenitor of the urothelium and the urethral epithelium is the early fetal urogenital sinus (UGS). The urethral plate and the urothelium are both formed from the p63+ cells of the UGS. Keratin 20 and uroplakins are exclusively expressed in urothelium, not in the urethral epithelium. Further research has to be done on unique markers for the urethral epithelium. This review has summarized the current knowledge about embryonic development of urothelium versus urethral epithelium and especially focuses on the influencing factors that are potentially specific for the eventual morphological differences of both cell linings, to be a basis for developmental or tissue engineering of urethral tissue.

Comparative analysis of cardiomyocyte differentiation from human embryonic stem cells under 3-D and 2-D culture conditions.

PubMed

Pal, Rajarshi; Mamidi, Murali Krishna; Das, Anjan Kumar; Bhonde, Ramesh

2013-02-01

Post-myocardial infarction cardiomyocytes are the most important target cell types for cardiac repair. Many of the applications envisaged for human embryonic stem cells (hESC)-derived cardiomyocytes demand that the differentiation procedure be robust, cost effective and high yielding. Various lines of evidence including our earlier study suggest that hESCs have distinct preferences to become heart cells. However, a direct comparison between different protocols has not yet been reported to date. Here, we performed a logical and systematic comparison of cardiomyocytes obtained from hESCs via embryoid bodies (EBs) in suspension versus adherent static cultures of feeder-free hES colonies representing three-dimensional (3-D) and two-dimensional (2-D) culture systems, respectively. An in-depth characterization of the beating cells revealed appropriate cardiac marker expression both at gene and protein levels. Despite using similar media, 3-D and 2-D cultures showed significant variation in growth and ability to form beating areas. While the expression of pre-cardiac mesoderm markers like GATA-4, HAND1, Myf5, Msx1, and BMP-IIR remained unaltered; levels of functional heart-specific markers such as MLC-2A/2V, cTnT, ANP, Phospholamban, α-MHC and KV4.3 were substantially up-regulated in 3-D compared to 2-D cultures. Concurrently we observed a sharp decline in the expression of ESC, ectoderm and endoderm markers including Oct-4, Sox-2, NFH, Sox-1, Sox-17 and AFP. Further immunocytochemistry and flow cytometry demonstrated a higher percentage of cells positive for Brachyury, desmin and cardiac troponin in 3-D cultures. Our results underscore the higher efficiency of cardiomyocytes derived via 3-D cultures. This finding enriches our basic understanding of the differentiation pattern in hESC-derived cardiomyocytes. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Cucumber metal tolerance protein CsMTP9 is a plasma membrane H⁺-coupled antiporter involved in the Mn²⁺ and Cd²⁺ efflux from root cells.

PubMed

Migocka, Magdalena; Papierniak, Anna; Kosieradzka, Anna; Posyniak, Ewelina; Maciaszczyk-Dziubinska, Ewa; Biskup, Robert; Garbiec, Arnold; Marchewka, Tadeusz

2015-12-01

Members of the plant metal tolerance protein (MTP) family have been classified into three major groups - Zn-CDF, Mn-CDF and Zn/Fe-CDF - however, the selectivity of most of the MTPs has not been confirmed yet. Cucumber gene CsMTP9 encoding a putative CDF transporter homologous to members of the Mn-CDF cluster is expressed exclusively in roots. The relative abundance of CsMTP9 transcript and protein in roots is significantly increased under Mn excess and Cd. Immunolocalization with specific antibodies revealed that CsMTP9 is a plasma membrane transporter that localizes to the inner PM domain of root endodermal cells. The plasma membrane localization of CsMTP9 was confirmed by the expression of the fusion proteins of GFP (green fluorescent protein) and CsMTP9 in yeast and protoplasts prepared from Arabidopsis cells. In yeast, CsMTP9 transports Mn(2+) and Cd(2+) via a proton-antiport mechanism with an apparent Km values of approximately 10 μm and 2.5 μm for Mn(2+) and Cd(2+) , respectively. In addition, CsMTP9 expression in yeast rescues the Mn- and Cd-hypersensitive phenotypes through the enhanced efflux of Mn(2+) and Cd(2+) from yeast cells. Similarly, the overexpression of CsMTP9 in A. thaliana confers increased resistance of plants to Mn excess and Cd but not to other heavy metals and leads to the enhanced translocation of manganese and cadmium from roots to shoots. These findings indicate that CsMTP9 is a plasma membrane H(+) -coupled Mn(2+) and Cd(2+) antiporter involved in the efflux of manganese and cadmium from cucumber root cells by the transport of both metals from endodermis into vascular cylinder. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Generation of functional hepatocyte-like cells from human deciduous periodontal ligament stem cells.

PubMed

Vasanthan, Punitha; Jayaraman, Pukana; Kunasekaran, Wijenthiran; Lawrence, Anthony; Gnanasegaran, Nareshwaran; Govindasamy, Vijayendran; Musa, Sabri; Kasim, Noor Hayaty Abu

2016-08-01

Human deciduous periodontal ligament stem cells have been introduced for as an easily accessible source of stem cells from dental origin. Although recent studies have revealed the ability of these stem cells in multipotential attribute, their efficiency of hepatic lineage differentiation has not been addressed so far. The aim of this study is to investigate hepatic lineage fate competence of periodontal ligament stem cells through direct media induction. Differentiation of periodontal ligament stem cells into hepatocyte-like cells was conducted by the exposure of two phase media induction. First phase was performed in the presence of hepatocyte growth factors to induce a definitive endoderm formation. In the subsequent phase, the cells were treated with oncostatin M and dexamethosone followed by insulin and transferrin to generate hepatocyte-like cells. Hepatic-related characters of the generated hepatocyte-like cells were determined at both mRNA and protein level followed by functional assays. Foremost changes observed in the generation of hepatocyte-like cells were the morphological features in which these cells were transformed from fibroblastic shape to polygonal shape. Temporal expression of hepatic markers ranging from early endodermal up to late markers were detected in the hepatocyte-like cells. Crucial hepatic markers such as glycogen storage, albumin, and urea secretion were also shown. These findings exhibited the ability of periodontal ligament stem cells of dental origin to be directed into hepatic lineage fate. These cells can be regarded as an alternative autologous source in the usage of stem cell-based treatment for liver diseases.

Multiphasic and tissue-specific roles of sonic hedgehog in cloacal septation and external genitalia development

PubMed Central

Seifert, Ashley W.; Bouldin, Cortney M.; Choi, Kyung-Suk; Harfe, Brian D.; Cohn, Martin J.

2009-01-01

Malformations of the external genitalia are among the most common congenital anomalies in humans. The urogenital and anorectal sinuses develop from the embryonic cloaca, and the penis and clitoris develop from the genital tubercle. Within the genital tubercle, the endodermally derived urethral epithelium functions as an organizer and expresses sonic hedgehog (Shh). Shh knockout mice lack external genitalia and have a persistent cloaca. This identified an early requirement for Shh, but precluded analysis of its later role in the genital tubercle. We conducted temporally controlled deletions of Shh and report that Shh is required continuously through the onset of sexual differentiation. Shh function is divisible into two temporal phases; an anogenital phase, during which Shh regulates outgrowth and patterning of the genital tubercle and septation of the cloaca, and a later external genital phase, during which Shh regulates urethral tube closure. Disruption of Shh function during the anogenital phase causes coordinated anorectal and genitourinary malformations, whereas inactivation during the external genital phase causes hypospadias. Shh directs cloacal septation by promoting cell proliferation in adjacent urorectal septum mesenchyme. Additionally, conditional inactivation of smoothened in the genital ectoderm and cloacal/urethral endoderm shows that the ectoderm is a direct target of Shh and is required for urethral tube closure, highlighting a novel role for genital ectoderm in urethragenesis. Identification of the stages during which disruption of Shh results in either isolated or coordinated malformations of anorectal and external genital organs provides a new tool for investigating the etiology of anogenital malformations in humans. PMID:19906862

Generation of functional hepatocyte-like cells from human deciduous periodontal ligament stem cells

NASA Astrophysics Data System (ADS)

Vasanthan, Punitha; Jayaraman, Pukana; Kunasekaran, Wijenthiran; Lawrence, Anthony; Gnanasegaran, Nareshwaran; Govindasamy, Vijayendran; Musa, Sabri; Kasim, Noor Hayaty Abu

2016-08-01

Human deciduous periodontal ligament stem cells have been introduced for as an easily accessible source of stem cells from dental origin. Although recent studies have revealed the ability of these stem cells in multipotential attribute, their efficiency of hepatic lineage differentiation has not been addressed so far. The aim of this study is to investigate hepatic lineage fate competence of periodontal ligament stem cells through direct media induction. Differentiation of periodontal ligament stem cells into hepatocyte-like cells was conducted by the exposure of two phase media induction. First phase was performed in the presence of hepatocyte growth factors to induce a definitive endoderm formation. In the subsequent phase, the cells were treated with oncostatin M and dexamethosone followed by insulin and transferrin to generate hepatocyte-like cells. Hepatic-related characters of the generated hepatocyte-like cells were determined at both mRNA and protein level followed by functional assays. Foremost changes observed in the generation of hepatocyte-like cells were the morphological features in which these cells were transformed from fibroblastic shape to polygonal shape. Temporal expression of hepatic markers ranging from early endodermal up to late markers were detected in the hepatocyte-like cells. Crucial hepatic markers such as glycogen storage, albumin, and urea secretion were also shown. These findings exhibited the ability of periodontal ligament stem cells of dental origin to be directed into hepatic lineage fate. These cells can be regarded as an alternative autologous source in the usage of stem cell-based treatment for liver diseases.

Neurenteric Cyst or Neuroendodermal Cyst? Immunohistochemical Study and Pathogenesis.

PubMed

Chen, Chun-Ting; Lai, Hung-Yi; Jung, Shih-Ming; Lee, Ching-Yi; Wu, Chieh-Tsai; Lee, Shih-Tseng

2016-12-01

Neurenteric cysts are rare central nervous system lesions derived from an endodermal origin. There is no consensus concerning pathogenesis because of the paucity of occurrences. We report an immunohistochemical study of 10 cases with neurenteric cysts and postulate its pathogenesis. Ten patients underwent surgical treatment for neurenteric cysts from 1995 to 2015. We retrospectively reviewed clinical, radiologic, operative, and pathologic findings for these patients. Immunohistochemical stains were completed in all cases to distinguish cell type and origin. Three cell types were identified: pseudostratified-ciliated, goblet-columnar, and simple cuboidal cells. All cases were positive for cytokeratin 7, and negative for cytokeratin 20, caudal-type homeobox 2, mucin 2, thyroid transcription factor 1, human chorionic gonadotropin, placental alkaline phosphatase, and cluster of differentiation 31. Four of them had positive staining for mucin 5AC, with expression only in goblet-columnar cells. According to the immunohistochemical results, the cells resembled the respiratory tract (pseudostratified-ciliated), stomach (goblet-columnar), and respiratory bronchioles (simple cuboidal). Seventy-five percent of cases with recurrence had a goblet-columnar component, emphasizing the importance of total resection of the cyst and complete pathologic examination. We postulate that the cystic tumor was derived from multipotent endodermal cells that migrated and traveled along the neuroectoderm, with incomplete differentiation into various cell types as a result of an unsuitable microenvironment. Because the neurenteric canal was only the channel of migration rather than a component of the cysts, the term neuroendodermal cysts is more precise in presenting the embryopathogenesis. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Characterization of a novel gravitropic mutant of morning glory, weeping2

NASA Astrophysics Data System (ADS)

Kitazawa, Daisuke; Miyazawa, Yutaka; Fujii, Nobuharu; Nitasaka, Eiji; Takahashi, Hideyuki

2008-09-01

In higher plants, gravity is a major environmental cue that governs growth orientation, a phenomenon termed gravitropism. It has been suggested that gravity also affects other aspects of morphogenesis, such as circumnutation and winding movements. Previously, we showed that these aspects of plant growth morphology require amyloplast sedimentation inside gravisensing endodermal cells. However, the molecular mechanism of the graviresponse and its relationship to circumnutation and winding remains obscure. Here, we have characterized a novel shoot gravitropic mutant of morning glory, weeping2 ( we2). In the we2 mutant, the gravitropic response of the stem was absent, and hypocotyls exhibited a severely reduced gravitropic response, whereas roots showed normal gravitropism. In agreement with our previous studies, we found that we2 mutant has defects in shoot circumnutation and winding. Histological analysis showed that we2 mutant forms abnormal endodermal cells. We identified a mutation in the morning glory homolog of SHORT-ROOT ( PnSHR1) that was genetically linked to the agravitropic phenotype of we2 mutant, and which may underlie the abnormal differentiation of endodermal cells in this plant. These results suggest that the phenotype of we2 mutant is due to a mutation of PnSHR1, and that PnSHR1 regulates gravimorphogenesis, including circumnutation and winding movements, in morning glory.

Disruption of the actin cytoskeleton results in the promotion of gravitropism in inflorescence stems and hypocotyls of Arabidopsis

NASA Technical Reports Server (NTRS)

Yamamoto, Kazuyoshi; Kiss, John Z.

2002-01-01

The actin cytoskeleton is hypothesized to play a major role in gravity perception and transduction mechanisms in roots of plants. To determine whether actin microfilaments (MFs) are involved in these processes in stem-like organs, we studied gravitropism in Arabidopsis inflorescence stems and hypocotyls. Localization studies using Alexa Fluor-phalloidin in conjugation with confocal microscopy demonstrated a longitudinally and transversely oriented actin MF network in endodermal cells of stems and hypocotyls. Latrunculin B (Lat-B) treatment of hypocotyls caused depolymerization of actin MFs in endodermal cells and a significant reduction of hypocotyl growth rates. Actin MFs in Lat-B-treated inflorescence stems also were disrupted, but growth rates were not affected. Despite disruption of the actin cytoskeleton in these two organs, Lat-B-treated stems and hypocotyls exhibited a promotion of gravitropic curvature in response to reorientation. In contrast, Lat-B reduced gravitropic curvature in roots but also reduced the growth rate. Thus, in contrast to prevailing hypotheses, our results suggest that actin MFs are not a necessary component of gravitropism in inflorescence stems and hypocotyls. Furthermore, this is the first study to demonstrate a prominent actin MF network in endodermal cells in the putative gravity-perceiving cells in stems.

Disruption of the Actin Cytoskeleton Results in the Promotion of Gravitropism in Inflorescence Stems and Hypocotyls of Arabidopsis1

PubMed Central

Yamamoto, Kazuyoshi; Kiss, John Z.

2002-01-01

The actin cytoskeleton is hypothesized to play a major role in gravity perception and transduction mechanisms in roots of plants. To determine whether actin microfilaments (MFs) are involved in these processes in stem-like organs, we studied gravitropism in Arabidopsis inflorescence stems and hypocotyls. Localization studies using Alexa Fluor-phalloidin in conjugation with confocal microscopy demonstrated a longitudinally and transversely oriented actin MF network in endodermal cells of stems and hypocotyls. Latrunculin B (Lat-B) treatment of hypocotyls caused depolymerization of actin MFs in endodermal cells and a significant reduction of hypocotyl growth rates. Actin MFs in Lat-B-treated inflorescence stems also were disrupted, but growth rates were not affected. Despite disruption of the actin cytoskeleton in these two organs, Lat-B-treated stems and hypocotyls exhibited a promotion of gravitropic curvature in response to reorientation. In contrast, Lat-B reduced gravitropic curvature in roots but also reduced the growth rate. Thus, in contrast to prevailing hypotheses, our results suggest that actin MFs are not a necessary component of gravitropism in inflorescence stems and hypocotyls. Furthermore, this is the first study to demonstrate a prominent actin MF network in endodermal cells in the putative gravity-perceiving cells in stems. PMID:11842170

Glucose responsive insulin production from human embryonic germ (EG) cell derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Gregory O.; Yochem, Robert L.; Axelman, Joyce

2007-05-11

Type 1 diabetes mellitus subjects millions to a daily burden of disease management, life threatening hypoglycemia and long-term complications such as retinopathy, nephropathy, heart disease, and stroke. Cell transplantation therapies providing a glucose-regulated supply of insulin have been implemented clinically, but are limited by safety, efficacy and supply considerations. Stem cells promise a plentiful and flexible source of cells for transplantation therapies. Here, we show that cells derived from human embryonic germ (EG) cells express markers of definitive endoderm, pancreatic and {beta}-cell development, glucose sensing, and production of mature insulin. These cells integrate functions necessary for glucose responsive regulation ofmore » preproinsulin mRNA and expression of insulin C-peptide in vitro. Following transplantation into mice, cells become insulin and C-peptide immunoreactive and produce plasma C-peptide in response to glucose. These findings suggest that EG cell derivatives may eventually serve as a source of insulin producing cells for the treatment of diabetes.« less

Auxin efflux facilitator and auxin dynamism responsible for the gravity-regulated development of peg in cucumber seedlings

NASA Astrophysics Data System (ADS)

Takahashi, Hideyuki; Watanabe, Chiaki; Fujii, Nobuharu; Miyazawa, Yutaka

Cucumber seedlings develop a protuberance, peg, by which seed coats are pulled out just af-ter germination. The peg is usually formed on the lower side of the transition zone between hypocotyl and root of the seedlings grown in a horizontal position. Our previous spaceflight experiment showed that unilateral positioning of a peg in cucumber seedlings occurred due to its suppression on the upper side of the transition zone because seedlings grown in microgravity developed a peg on each side of the transition zone. We also showed that auxin was a major factor responsible for peg development. There was a redistribution of auxin in the gravistimu-lated transition zone, decreasing IAA level on the upper side, and IAA application induced a peg on both lower and upper sides of the transition zone. In addition, peg was released from its suppression in the seedlings treated with inhibitors of auxin efflux. Namely, two pegs devel-oped in the TIBA-treated seedlings even when they were grown in a horizontal position. These results imply that a reduction of auxin level due to its efflux is required for the suppression of peg development on the upper side of the transition zone in a horizontal position. To under-stand molecular mechanism underlying the negative control of morphogenesis by graviresponse in cucumber seedlings, we isolated cDNAs of auxin efflux facilitators, CsPINs, from cucumber and examined the expressions of their proteins, in relation to the redistribution of endogenous auxin and peg development. We isolated six cDNAs of PIN homologues CsPIN1 to CsPIN6 from cucumber. By immunohistochemical study using some of their anti-bodies, we revealed that CsPIN1 was localized in endodermis, vascular tissue and pith around the transition zone of cucumber seedlings. In cucumber seedlings grown in a vertical position with radicles pointing down, CsPIN1 in endodermal cells was mainly localized on the plasma membrane neighboring vascular bundle but not on the plasma membrane next to the cortex. This CsPIN1 localization could play a role in transporting auxin from cortex to vascular bundle. In both vascular and pith tissues, CsPIN1 was localized on the bottom plasma membrane of the cells, which could allow auxin to move toward the roots. In the seedlings grown in a horizontal position, endoder-mal cells situated above the vascular bundle localized CsPIN1 on the lower plasma membrane, whereas the polarized localization of CsPIN1 in endodermal cells situated below the vascular bundle became less clear. This differential expression of CsPIN1 in the endodermis commenced within 30 min after gravistimulation. We measured endogenous IAA contents in the transi-tion zone of the 24-hour-old seedlings. In the longitudinally halved transition zone of seedlings grown in a horizontal position, free IAA content was significantly lowered in the upper side, compared to that of the lower side or either side of the transition zone in a vertical position. When 24-hour-old seedlings grown in a vertical position were gravistimulated by reorienting them to the horizontal, free IAA in the lower side of the transition zone increased by 30 min after gravistimulation and eventually decreased to the control level by 180 min after gravistim-ulation. IAA content in the upper side of the transition zone did not change much and was comparable to that in the vertical transition zone during 180 min after gravistimulation. Thus, it appears that gravistimulation causes an immediate increase of IAA level in the lower side and its eventual decrease in the upper side of the transition zone. The gravity-induced changes in CsPIN1 localization in endodermal cells could be involved in auxin redistribution that leads to unilateral positioning of a peg in cucumber seedlings.

Bud detachment in hydra requires activation of fibroblast growth factor receptor and a Rho–ROCK–myosin II signaling pathway to ensure formation of a basal constriction

PubMed Central

Holz, Oliver; Apel, David; Steinmetz, Patrick; Lange, Ellen; Hopfenmüller, Simon; Ohler, Kerstin; Sudhop, Stefanie

2017-01-01

Background: Hydra propagates asexually by exporting tissue into a bud, which detaches 4 days later as a fully differentiated young polyp. Prerequisite for detachment is activation of fibroblast growth factor receptor (FGFR) signaling. The mechanism which enables constriction and tissue separation within the monolayered ecto‐ and endodermal epithelia is unknown. Results: Histological sections and staining of F‐actin by phalloidin revealed conspicuous cell shape changes at the bud detachment site indicating a localized generation of mechanical forces and the potential enhancement of secretory functions in ectodermal cells. By gene expression analysis and pharmacological inhibition, we identified a candidate signaling pathway through Rho, ROCK, and myosin II, which controls bud base constriction and rearrangement of the actin cytoskeleton. Specific regional myosin phosphorylation suggests a crucial role of ectodermal cells at the detachment site. Inhibition of FGFR, Rho, ROCK, or myosin II kinase activity is permissive for budding, but represses myosin phosphorylation, rearrangement of F‐actin and constriction. The young polyp remains permanently connected to the parent by a broad tissue bridge. Conclusions: Our data suggest an essential role of FGFR and a Rho‐ROCK‐myosin II pathway in the control of cell shape changes required for bud detachment. Developmental Dynamics 246:502–516, 2017. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists PMID:28411398

Bud detachment in hydra requires activation of fibroblast growth factor receptor and a Rho-ROCK-myosin II signaling pathway to ensure formation of a basal constriction.

PubMed

Holz, Oliver; Apel, David; Steinmetz, Patrick; Lange, Ellen; Hopfenmüller, Simon; Ohler, Kerstin; Sudhop, Stefanie; Hassel, Monika

2017-07-01

Hydra propagates asexually by exporting tissue into a bud, which detaches 4 days later as a fully differentiated young polyp. Prerequisite for detachment is activation of fibroblast growth factor receptor (FGFR) signaling. The mechanism which enables constriction and tissue separation within the monolayered ecto- and endodermal epithelia is unknown. Histological sections and staining of F-actin by phalloidin revealed conspicuous cell shape changes at the bud detachment site indicating a localized generation of mechanical forces and the potential enhancement of secretory functions in ectodermal cells. By gene expression analysis and pharmacological inhibition, we identified a candidate signaling pathway through Rho, ROCK, and myosin II, which controls bud base constriction and rearrangement of the actin cytoskeleton. Specific regional myosin phosphorylation suggests a crucial role of ectodermal cells at the detachment site. Inhibition of FGFR, Rho, ROCK, or myosin II kinase activity is permissive for budding, but represses myosin phosphorylation, rearrangement of F-actin and constriction. The young polyp remains permanently connected to the parent by a broad tissue bridge. Our data suggest an essential role of FGFR and a Rho-ROCK-myosin II pathway in the control of cell shape changes required for bud detachment. Developmental Dynamics 246:502-516, 2017. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

Urine-derived induced pluripotent stem cells as a modeling tool for paroxysmal kinesigenic dyskinesia.

PubMed

Zhang, Shu-Zhen; Li, Hong-Fu; Ma, Li-Xiang; Qian, Wen-Jing; Wang, Zhong-Feng; Wu, Zhi-Ying

2015-11-30

Paroxysmal kinesigenic dyskinesia (PKD) is a monogenic movement disorder with autosomal dominant inheritance. We previously identified the proline-rich transmembrane protein 2 (PRRT2) as a causative gene of PKD. However, the pathogenesis of PKD remains largely unknown so far. In addition, applicable modeling tools to investigate the underlying mechanisms of PKD are still lacking. The combination of disease-specific human induced pluripotent stem cells (iPSCs) and directed cell differentiation offers an ideal platform for disease modeling. In this study, we generated two iPSC lines from the renal epithelial cells of one PKD patient with the hotspot c.649dupC mutation (PKD-iPSCs). These cell lines were positive for alkaline phosphatase Nanog, Tra-1-80, Tra-1-60, SSEA-3 and SSEA-4. Teratomas with three blastoderms including ectoderm, mesoderm, and endoderm were obtained two months after injection of PKD-iPSCs into NOD/SCID mice. The expression of PRRT2 mRNA was decreased in PKD-iPSCs compared with that of the control iPSCs. Furthermore, PKD-iPSCs possessed the differentiation potential of functional glutamatergic, dopaminergic and motor neurons in vitro. Electrophysiological examinations revealed that the current densities of fast activated and deactivated sodium channels as well as voltage gated potassium channels were not different between the neurons from PKD-iPSCs and control iPSCs. Thus, PKD-iPSCs are a feasible modeling tool to investigate the pathogenic mechanisms of PKD. © 2015. Published by The Company of Biologists Ltd.

An insulin signaling feedback loop regulates pancreas progenitor cell differentiation during islet development and regeneration

PubMed Central

Ye, Lihua; Robertson, Morgan A.; Mastracci, Teresa L.; Anderson, Ryan M.

2016-01-01

As one of the key nutrient sensors, insulin signaling plays an important role in integrating environmental energy cues with organism growth. In adult organisms, relative insufficiency of insulin signaling induces compensatory expansion of insulin-secreting pancreatic beta (β) cells. However, little is known about how insulin signaling feedback might influence neogenesis of β cells during embryonic development. Using genetic approaches and a unique cell transplantation system in developing zebrafish, we have uncovered a novel role for insulin signaling in the negative regulation of pancreatic progenitor cell differentiation. Blocking insulin signaling in the pancreatic progenitors hastened the expression of the essential β cell genes insulin and pdx1, and promoted β cell fate at the expense of alpha cell fate. In addition, loss of insulin signaling promoted β cell regeneration and destabilization of alpha cell character. These data indicate that insulin signaling constitutes a tunable mechanism for β cell compensatory plasticity during early development. Moreover, using a novel blastomere-to-larva transplantation strategy, we found that loss of insulin signaling in endoderm-committed blastomeres drove their differentiation into β cells. Furthermore, the extent of this differentiation was dependent on the function of the β cell mass in the host. Altogether, our results indicate that modulation of insulin signaling will be crucial for the development of β cell restoration therapies for diabetics; further clarification of the mechanisms of insulin signaling in β cell progenitors will reveal therapeutic targets for both in vivo and in vitro β cell generation. PMID:26658317

Prohibitin 2 Regulates the Proliferation and Lineage-Specific Differentiation of Mouse Embryonic Stem Cells in Mitochondria

PubMed Central

Komazaki, Shinji; Enomoto, Kei; Seki, Yasuhiro; Wang, Ying Ying; Ishigaki, Yohei; Ninomiya, Naoto; Noguchi, Taka-aki K.; Kokubu, Yuko; Ohnishi, Keigoh; Nakajima, Yoshiro; Kato, Kaoru; Intoh, Atsushi; Takada, Hitomi; Yamakawa, Norio; Wang, Pi-Chao; Asashima, Makoto; Kurisaki, Akira

2014-01-01

Background The pluripotent state of embryonic stem (ES) cells is controlled by a network of specific transcription factors. Recent studies also suggested the significant contribution of mitochondria on the regulation of pluripotent stem cells. However, the molecules involved in these regulations are still unknown. Methodology/Principal Findings In this study, we found that prohibitin 2 (PHB2), a pleiotrophic factor mainly localized in mitochondria, is a crucial regulatory factor for the homeostasis and differentiation of ES cells. PHB2 was highly expressed in undifferentiated mouse ES cells, and the expression was decreased during the differentiation of ES cells. Knockdown of PHB2 induced significant apoptosis in pluripotent ES cells, whereas enhanced expression of PHB2 contributed to the proliferation of ES cells. However, enhanced expression of PHB2 strongly inhibited ES cell differentiation into neuronal and endodermal cells. Interestingly, only PHB2 with intact mitochondrial targeting signal showed these specific effects on ES cells. Moreover, overexpression of PHB2 enhanced the processing of a dynamin-like GTPase (OPA1) that regulates mitochondrial fusion and cristae remodeling, which could induce partial dysfunction of mitochondria. Conclusions/Significance Our results suggest that PHB2 is a crucial mitochondrial regulator for homeostasis and lineage-specific differentiation of ES cells. PMID:24709813

Why are hematopoietic stem cells so 'sexy'? on a search for developmental explanation.

PubMed

Ratajczak, M Z

2017-08-01

Evidence has accumulated that normal human and murine hematopoietic stem cells express several functional pituitary and gonadal sex hormones, and that, in fact, some sex hormones, such as androgens, have been employed for many years to stimulate hematopoiesis in patients with bone marrow aplasia. Interestingly, sex hormone receptors are also expressed by leukemic cell lines and blasts. In this review, I will discuss the emerging question of why hematopoietic cells express these receptors. A tempting hypothetical explanation for this phenomenon is that hematopoietic stem cells are related to subpopulation of migrating primordial germ cells. To support of this notion, the anatomical sites of origin of primitive and definitive hematopoiesis during embryonic development are tightly connected with the migratory route of primordial germ cells: from the proximal epiblast to the extraembryonic endoderm at the bottom of the yolk sac and then back to the embryo proper via the primitive streak to the aorta-gonado-mesonephros (AGM) region on the way to the genital ridges. The migration of these cells overlaps with the emergence of primitive hematopoiesis in the blood islands at the bottom of the yolk sac, and definitive hematopoiesis that occurs in hemogenic endothelium in the embryonic dorsal aorta in AGM region.

Wnt4 is essential to normal mammalian lung development.

PubMed

Caprioli, Arianna; Villasenor, Alethia; Wylie, Lyndsay A; Braitsch, Caitlin; Marty-Santos, Leilani; Barry, David; Karner, Courtney M; Fu, Stephen; Meadows, Stryder M; Carroll, Thomas J; Cleaver, Ondine

2015-10-15

Wnt signaling is essential to many events during organogenesis, including the development of the mammalian lung. The Wnt family member Wnt4 has been shown to be required for the development of kidney, gonads, thymus, mammary and pituitary glands. Here, we show that Wnt4 is critical for proper morphogenesis and growth of the respiratory system. Using in situ hybridization in mouse embryos, we identify a previously uncharacterized site of Wnt4 expression in the anterior trunk mesoderm. This expression domain initiates as early as E8.25 in the mesoderm abutting the tracheoesophageal endoderm, between the fusing dorsal aortae and the heart. Analysis of Wnt4(-/-) embryos reveals severe lung hypoplasia and tracheal abnormalities; however, aortic fusion and esophageal development are unaffected. We find decreased cell proliferation in Wnt4(-/-) lung buds, particularly in tip domains. In addition, we observe reduction of the important lung growth factors Fgf9, Fgf10, Sox9 and Wnt2 in the lung bud during early stages of organogenesis, as well as decreased tracheal expression of the progenitor factor Sox9. Together, these data reveal a previously unknown role for the secreted protein Wnt4 in respiratory system development. Copyright © 2015. Published by Elsevier Inc.

Stimulation of cAMP signalling allows isolation of clonal pancreatic precursor cells from adult mouse pancreas.

PubMed

Yamamoto, T; Yamato, E; Taniguchi, H; Shimoda, M; Tashiro, F; Hosoi, M; Sato, T; Fujii, S; Miyazaki, J-I

2006-10-01

Duct cells of the pancreas are thought to include latent progenitors of islet endocrine cells that can be induced to differentiate by appropriate morphogens. Here we developed a method for isolating pancreatic ductal epithelial cells from adult mice that overcomes the shortcomings of previous methods. Pancreatic ductal cells were grown in serum-free DMEM/F12 medium in the presence of cholera toxin or 8-bromo-cyclic adenosine monophosphate, which is known to be an intracellular cAMP generator. Single cell cloning was performed by limiting dilution in serum-free medium. The isolated clonal cells expressed high levels of cytokeratin and Ipf1 (formerly known as Pdx-1). Adenovirus-mediated expression of ngn3 (also known as Neurog3) and Ptf1a in these cells induced expression of insulin and somatostatin, and of carboxypeptidase A, respectively. Furthermore, albumin production was induced by dexamethasone or by long-term culture in serum-containing medium. Stimulation of the cAMP-dependent signalling allowed us to isolate clonal pancreatic ductal cells from adult mice. These cells are able to partially differentiate into endocrine cells, exocrine cells and hepatocyte-like cells and are therefore considered to have the characteristics of endodermal progenitor cells.

Nucleic acid and protein synthesis during lateral root initiation in Marsilea quadrifolia (Marsileaceae)

NASA Technical Reports Server (NTRS)

Lin, B. L.; Raghavan, V.

1991-01-01

The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Consistent with histological studies, derivatives of the lateral root initial as well as the cells of the adjacent inner cortex and pericycle of the parent root also continued to synthesize DNA. RNA and protein synthetic activities were found to be higher in the lateral root initials than in the endodermal initials of the same longitudinal layer. The data suggest a role for nucleic acid and protein synthesis during cytodifferentiation of a potential endodermal cell into a lateral root initial.

Genome-Wide Analysis Reveals the Unique Stem Cell Identity of Human Amniocytes

PubMed Central

Maguire, Colin T.; Demarest, Bradley L.; Hill, Jonathon T.; Palmer, James D.; Brothman, Arthur R.; Yost, H. Joseph; Condic, Maureen L.

2013-01-01

Human amniotic fluid contains cells that potentially have important stem cell characteristics, yet the programs controlling their developmental potency are unclear. Here, we provide evidence that amniocytes derived from multiple patients are marked by heterogeneity and variability in expression levels of pluripotency markers. Clonal analysis from multiple patients indicates that amniocytes have large pools of self-renewing cells that have an inherent property to give rise to a distinct amniocyte phenotype with a heterogeneity of pluripotent markers. Significant to their therapeutic potential, genome-wide profiles are distinct at different gestational ages and times in culture, but do not differ between genders. Based on hierarchical clustering and differential expression analyses of the entire transcriptome, amniocytes express canonical regulators associated with pluripotency and stem cell repression. Their profiles are distinct from human embryonic stem cells (ESCs), induced-pluripotent stem cells (iPSCs), and newborn foreskin fibroblasts. Amniocytes have a complex molecular signature, coexpressing trophoblastic, ectodermal, mesodermal, and endodermal cell-type-specific regulators. In contrast to the current view of the ground state of stem cells, ESCs and iPSCs also express high levels of a wide range of cell-type-specific regulators. The coexpression of multilineage differentiation markers combined with the strong expression of a subset of ES cell repressors in amniocytes suggests that these cells have a distinct phenotype that is unlike any other known cell-type or lineage. PMID:23326421

Immunohistochemical distribution of early pregnancy factor in ovary, oviduct and placenta of pregnant gilts.

PubMed

Grosso, M C; Bellingeri, R V; Motta, C E; Alustiza, F E; Picco, N Y; Vivas, A B

2015-01-01

Early pregnancy factor (EPF) is an immunosuppressant that promotes maternal immune system tolerance of the allogenic fetus. Little is known about localization of this factor in different tissues and nothing has been reported about localization in swine reproductive and placental tissues. We determined the concentration of EPF in serum of gilts and porcine placenta conditioned medium (PPCM). We also analyzed the expression of EPF in different reproductive tissues of pregnant gilts at 10, 30, 60 and 90 days of pregnancy. EPF concentration in serum and PPCM was determined by western blot and densitometry. EPF expression in reproductive tissue was assessed by immunohistochemistry. The highest concentration of EPF was observed at 30 days in serum and PPCM; the concentration was higher in PPCM than in serum at the stages we evaluated. All reproductive tissues from the gestational stages analyzed showed specific labeling of EPF, but this labeling did not appear in non-pregnant gilts. At 30 days pregnancy, the EPF expression in the ovary was predominantly in follicular lutein cells, probably owing to its function as a luteotrophic factor. In the oviduct, EPF was expressed in unciliated secretory epithelial cells and in the cilia of ciliated cells. In the placenta, EPF was expressed in the fetal portion (mesoderm chorioallantois and epithelium of endoderm). EPF acts as an autocrine and paracrine growth factor for the trophoblast during the peri-implantation period.

APELA promotes tumour growth and cell migration in ovarian cancer in a p53-dependent manner.

PubMed

Yi, Yuyin; Tsai, Shu-Huei; Cheng, Jung-Chien; Wang, Evan Y; Anglesio, Michael S; Cochrane, Dawn R; Fuller, Megan; Gibb, Ewan A; Wei, Wei; Huntsman, David G; Karsan, Aly; Hoodless, Pamela A

2017-12-01

APELA is a small, secreted peptide that can function as a ligand for the G-protein coupled receptor, Apelin Receptor (APLNR, APJ). APELA plays an essential role in endoderm differentiation and cardiac development during embryogenesis. We investigated whether APELA exerts any functions in cancer progression. The Cancer Genome Atlas (TCGA) RNA sequencing datasets, microarray from an OCCC mouse model, and RNA isolated from fresh frozen and FFPE patient tissue were used to assess APELA expression. APELA knockout ovarian clear cell carcinoma (OCCC) cell lines were generated using CRISPR/Cas9. APELA was expressed in various ovarian cancer histotypes and was especially elevated in OCCC. Disruption of APELA expression in OCCC cell lines suppressed cell growth and migration, and altered cell-cycle progression. Moreover, addition of human recombinant APELA peptide to the OCCC cell line OVISE promoted cell growth and migration. Interestingly, OVISE cells do not express APLNR, suggesting that APELA can function through an APLNR-independent pathway. Furthermore, APELA affected cell growth and cell cycle progression in a p53-dependent manner. In addition, APELA knockdown induced p53 expression in cancer cell lines. Our findings uncover a potential oncogenic role for APELA in promoting ovarian tumour progression and provide a possible therapeutic strategy in ovarian cancer by targeting APELA. Copyright © 2017 Elsevier Inc. All rights reserved.

A new centrifuge microscope reveals that mobile plastids trigger gravity sensing in Arabidopsis inflorescence stems

NASA Astrophysics Data System (ADS)

Toyota, Masatsugu; Tasaka, Masao; Morita, Miyo T.; Gilroy, Simon

2012-07-01

The starch-statolith hypothesis is the most widely accepted model for plant gravity sensing and proposes that the sedimentation of high-density starch-filled plastids (amyloplasts) in shoot endodermal cells and root columella cells is important for gravity sensing of each organ. However, starch-deficient phosphoglucomutase (pgm-1) mutants sense gravity and show gravitropism in inflorescence stems, even though most starchless amyloplasts in this mutant fail to sediment toward the gravity vector. These results raise the questions about the role of starch in gravity sensing and the features of statolith/statocyte essential for shoot gravity sensing. To address these questions, we developed a new centrifuge microscope and analyzed two gravitropic mutants, i.e., pgm-1 and endodermal-amyloplast less 1 (eal1). All optical devices (e.g., objective lens, light source and CCD camera) and specimens were rotated on a direct-drive motor, and acquired images were wirelessly transmitted during centrifugation. Live-cell imaging during centrifugation revealed that the starchless amyloplasts sedimented to the hypergravity vector (10 and 30 g) in endodermal cells of pgm-1 stems, indicating that the density of the starchless amyloplasts is higher than that of cytoplasm. Electron micrographs of shoot endodermal cells in pgm-1 mutants suggested that the starchless amyloplast contains an organized thylakoid membrane but not starch granules, which morphologically resembles chloroplasts in the adjacent cortical cells. Therefore, the shoot amyloplasts without starch are possibly as dense as chloroplasts. We examined eal1 mutants, an allele of shoot gravitropism (sgr) 7/short-root (shr), which also have starchless amyloplasts due to abnormal differentiation of amyloplasts and show no gravitropic response at 1 g. Hypergravity up to 30 g induced little gravitropism in eal1 stems and the starchless amyloplasts failed to sediment under 30 g conditions. However, the eal1 mutants treated with latrunculin B, an actin disrupting drug, showed gravitropism under 30 g conditions, during which amyloplasts were artificially sedimented by hypergravity. These results suggest that shoot amyloplasts are intrinsically dense enough to trigger gravity sensing without starch and, rather, intracellular environments that render amyloplasts sedimentable/mobile, such as actin organization, are essential for gravity sensing in Arabidopsis inflorescence stems.

Dissecting engineered cell types and enhancing cell fate conversion via CellNet

PubMed Central

Morris, Samantha A.; Cahan, Patrick; Li, Hu; Zhao, Anna M.; San Roman, Adrianna K.; Shivdasani, Ramesh A.; Collins, James J.; Daley, George Q.

2014-01-01

SUMMARY Engineering clinically relevant cells in vitro holds promise for regenerative medicine, but most protocols fail to faithfully recapitulate target cell properties. To address this, we developed CellNet, a network biology platform that determines whether engineered cells are equivalent to their target tissues, diagnoses aberrant gene regulatory networks, and prioritizes candidate transcriptional regulators to enhance engineered conversions. Using CellNet, we improved B cell to macrophage conversion, transcriptionally and functionally, by knocking down predicted B cell regulators. Analyzing conversion of fibroblasts to induced hepatocytes (iHeps), CellNet revealed an unexpected intestinal program regulated by the master regulator Cdx2. We observed long-term functional engraftment of mouse colon by iHeps, thereby establishing their broader potential as endoderm progenitors and demonstrating direct conversion of fibroblasts into intestinal epithelium. Our studies illustrate how CellNet can be employed to improve direct conversion and to uncover unappreciated properties of engineered cells. PMID:25126792

Formation and hematopoietic differentiation of human embryoid bodies by suspension and hanging drop cultures.

PubMed

Cerdan, Chantal; Hong, Seok Ho; Bhatia, Mickie

2007-10-01

The in vitro aggregation of human embryonic stem cells (hESCs) into clusters termed embryoid bodies (EBs) allows for the spontaneous differentiation of cells representing endoderm, mesoderm, and ectoderm lineages. This stochastic process results however, in the generation of low numbers of differentiated cells, and can be enhanced to some extent by the addition of exogenous growth factors or overexpression of regulatory genes. In the authors' laboratory, the use of hematopoietic cytokines in combination with the mesoderm inducer bone morphogenetic protein-4 (BMP-4) was able to generate up to 90% of CD45(+) hematopoietic cells with colony-forming unit (CFU) activity. This unit describes two protocols that have been successfully applied in the authors' laboratory for the generation of EBs in (1) suspension and (2) hanging drop (HD) cultures from enzymatically digested clumps of undifferentiated hESC colonies.

Resistance and Resistant Reaction of Gossypium arboreum to the Reniform, Nematode, Rotylenchulus reniformis

PubMed Central

Carter, William W.

1981-01-01

Gossypium arboreum 'Nanking CB 1402' possessed a high level of resistance to Rotylenchulus reniformis. Within 16 h, the nematode penetrated roots of resistant and susceptible cottons equally. After 36 h, significantly fewer nematodes were found in resistant roots. Larvae fed in either an endodermal or pericyclic cell and had no specificity for root tissue of a particular age. In roots of resistant G. arboreum '1402,' wall breakdown of pericyclic cells was evident after 3 d, endodermal and cortical cells collapsed, and the hypertrophied pericyclic cells disintegrated within 12 d. Cell walls immediately adjacent to the nematode's head were thickened and more safranin positive in resistant than in susceptible cotton cultivars. Several other cultivars of G. arboreum were also resistant to R. reniformis, based on nematode fecundity and percent egg reduction. PMID:19300777

The structure and development of the starch sheath in pea epicotyls

NASA Technical Reports Server (NTRS)

Sack, D. F.

1985-01-01

Graviperception in plant stems is thought to occur in endodermal cells differentiated as a starch sheath, but little is known about the ultrastructure of these cells in dicots. The structure of the pea starch sheath was studied with respect to gravity and to development in order to determine whether symplastic or apoplastic blockages exist and to describe any intracellular polarity. Amyloplasts increase in size towards the base of the epicotyl hook but are not consistently sedimented until the cells enter the zone exhibiting gravicurvature below the hook. The starch sheath cells are connected to each other and to cells of the cortex and the stele by plasmodesmata. A casparian strip exists in older endodermal cells but not at the stage that the endodermis is differentiated as a starch sheath. Amyloplasts were frequently observed in apparent contact with endoplasmic reticulum.

FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sui, Lina, E-mail: linasui@vub.ac.be; Mfopou, Josue K.; Geens, Mieke

2012-09-28

Highlights: Black-Right-Pointing-Pointer Deep study the FGF signaling role during DE specification in the context of hESCs. Black-Right-Pointing-Pointer DE differentiation from hESCs has an early dependence on FGF signaling. Black-Right-Pointing-Pointer A serum-free DE protocol is developed based on the findings. Black-Right-Pointing-Pointer The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study,more » we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.« less

The nuclear hormone receptor family member NR5A2 controls aspects of multipotent progenitor cell formation and acinar differentiation during pancreatic organogenesis.

PubMed

Hale, Michael A; Swift, Galvin H; Hoang, Chinh Q; Deering, Tye G; Masui, Toshi; Lee, Youn-Kyoung; Xue, Jumin; MacDonald, Raymond J

2014-08-01

The orphan nuclear receptor NR5A2 is necessary for the stem-like properties of the epiblast of the pre-gastrulation embryo and for cellular and physiological homeostasis of endoderm-derived organs postnatally. Using conditional gene inactivation, we show that Nr5a2 also plays crucial regulatory roles during organogenesis. During the formation of the pancreas, Nr5a2 is necessary for the expansion of the nascent pancreatic epithelium, for the subsequent formation of the multipotent progenitor cell (MPC) population that gives rise to pre-acinar cells and bipotent cells with ductal and islet endocrine potential, and for the formation and differentiation of acinar cells. At birth, the NR5A2-deficient pancreas has defects in all three epithelial tissues: a partial loss of endocrine cells, a disrupted ductal tree and a >90% deficit of acini. The acinar defects are due to a combination of fewer MPCs, deficient allocation of those MPCs to pre-acinar fate, disruption of acinar morphogenesis and incomplete acinar cell differentiation. NR5A2 controls these developmental processes directly as well as through regulatory interactions with other pancreatic transcriptional regulators, including PTF1A, MYC, GATA4, FOXA2, RBPJL and MIST1 (BHLHA15). In particular, Nr5a2 and Ptf1a establish mutually reinforcing regulatory interactions and collaborate to control developmentally regulated pancreatic genes by binding to shared transcriptional regulatory regions. At the final stage of acinar cell development, the absence of NR5A2 affects the expression of Ptf1a and its acinar specific partner Rbpjl, so that the few acinar cells that form do not complete differentiation. Nr5a2 controls several temporally distinct stages of pancreatic development that involve regulatory mechanisms relevant to pancreatic oncogenesis and the maintenance of the exocrine phenotype. © 2014. Published by The Company of Biologists Ltd.

Hepassocin is required for hepatic outgrowth during zebrafish hepatogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Ming; Beijing Institute of Radiation Medicine, Beijing 100850; Yan, Hui

2015-07-31

Background & aims: Hepassocin (HPS) is a hepatotrophic growth factor that specifically stimulates hepatocyte proliferation and promotes liver regeneration after liver damage. In this paper, zebrafish were used to investigate the role of HPS in liver development. Methods and results: During zebrafish development, HPS expression is enriched in liver throughout hepatogenesis. Knockdown of HPS using its specific morpholino leads to a smaller liver phenotype. Further results showed that the HPS knockdown has no effect on the expression of the early endoderm marker gata6 and early hepatic marker hhex. In addition, results showed that the smaller-liver phenotype in HPS morphants wasmore » caused by suppression of cell proliferation, not induction of cell apoptosis. Conclusions: Current findings indicated that HPS is essential to the later stages of development in vertebrate liver organogenesis. - Highlights: • HPS is enriched in zebrafish liver and has strong similarities with other species. • Knocking down HPS with MOs results in small liver phenotype. • HPS depletion regulates liver outgrowth but not liver specification and budding. • HPS depletion causes hepatocyte proliferation arrest but not apoptosis induction.« less

Transdifferentiation of human periodontal ligament stem cells into pancreatic cell lineage.

PubMed

Lee, Jeong Seok; An, Seong Yeong; Kwon, Il Keun; Heo, Jung Sun

2014-10-01

Human periodontal ligament-derived stem cells (PDLSCs) demonstrate self-renewal capacity and multilineage differentiation potential. In this study, we investigated the transdifferentiation potential of human PDLSCs into pancreatic islet cells. To form three-dimensional (3D) clusters, PDLSCs were cultured in Matrigel with media containing differentiation-inducing agents. We found that after 6 days in culture, PDLSCs underwent morphological changes resembling pancreatic islet-like cell clusters (ICCs). The morphological characteristics of PDLSC-derived ICCs were further assessed using scanning electron microscopy analysis. Using reverse transcription-polymerase chain reaction analysis, we found that pluripotency genes were downregulated, whereas early endoderm and pancreatic differentiation genes were upregulated, in PDLSC-derived ICCs compared with undifferentiated PDLSCs. Furthermore, we found that PDLSC-derived ICCs were capable of secreting insulin in response to high concentrations of glucose, validating their functional differentiation into islet cells. Finally, we also performed dithizone staining, as well as immunofluorescence assays and fluorescence-activated cell sorting analysis for pancreatic differentiation markers, to confirm the differentiation status of PDLSC-derived ICCs. These results demonstrate that PDLSCs can transdifferentiate into functional pancreatic islet-like cells and provide a novel, alternative cell population for pancreatic repair. Copyright © 2014 John Wiley & Sons, Ltd.

Generation of embryos directly from embryonic stem cells by tetraploid embryo complementation reveals a role for GATA factors in organogenesis.

PubMed

Duncan, S A

2005-12-01

Gene targeting in ES (embryonic stem) cells has been used extensively to study the role of proteins during embryonic development. In the traditional procedure, this requires the generation of chimaeric mice by introducing ES cells into blastocysts and allowing them to develop to term. Once chimaeric mice are produced, they are bred into a recipient mouse strain to establish germline transmission of the allele of interest. Although this approach has been used very successfully, the breeding cycles involved are time consuming. In addition, genes that are essential for organogenesis often have roles in the formation of extra-embryonic tissues that are essential for early stages of post-implantation development. For example, mice lacking the GATA transcription factors, GATA4 or GATA6, arrest during gastrulation due to an essential role for these factors in differentiation of extra-embryonic endoderm. This lethality has frustrated the study of these factors during the development of organs such as the liver and heart. Extraembryonic defects can, however, be circumvented by generating clonal mouse embryos directly from ES cells by tetraploid complementation. Here, we describe the usefulness and efficacy of this approach using GATA factors as an example.

DNA Methylation Profiling of Embryonic Stem Cell Differentiation into the Three Germ Layers

PubMed Central

Isagawa, Takayuki; Nagae, Genta; Shiraki, Nobuaki; Fujita, Takanori; Sato, Noriko; Ishikawa, Shumpei; Kume, Shoen; Aburatani, Hiroyuki

2011-01-01

Embryogenesis is tightly regulated by multiple levels of epigenetic regulation such as DNA methylation, histone modification, and chromatin remodeling. DNA methylation patterns are erased in primordial germ cells and in the interval immediately following fertilization. Subsequent developmental reprogramming occurs by de novo methylation and demethylation. Variance in DNA methylation patterns between different cell types is not well understood. Here, using methylated DNA immunoprecipitation and tiling array technology, we have comprehensively analyzed DNA methylation patterns at proximal promoter regions in mouse embryonic stem (ES) cells, ES cell-derived early germ layers (ectoderm, endoderm and mesoderm) and four adult tissues (brain, liver, skeletal muscle and sperm). Most of the methylated regions are methylated across all three germ layers and in the three adult somatic tissues. This commonly methylated gene set is enriched in germ cell-associated genes that are generally transcriptionally inactive in somatic cells. We also compared DNA methylation patterns by global mapping of histone H3 lysine 4/27 trimethylation, and found that gain of DNA methylation correlates with loss of histone H3 lysine 4 trimethylation. Our combined findings indicate that differentiation of ES cells into the three germ layers is accompanied by an increased number of commonly methylated DNA regions and that these tissue-specific alterations in methylation occur for only a small number of genes. DNA methylation at the proximal promoter regions of commonly methylated genes thus appears to be an irreversible mark which functions to fix somatic lineage by repressing the transcription of germ cell-specific genes. PMID:22016810

DNA methylation profiling of embryonic stem cell differentiation into the three germ layers.

PubMed

Isagawa, Takayuki; Nagae, Genta; Shiraki, Nobuaki; Fujita, Takanori; Sato, Noriko; Ishikawa, Shumpei; Kume, Shoen; Aburatani, Hiroyuki

2011-01-01

Embryogenesis is tightly regulated by multiple levels of epigenetic regulation such as DNA methylation, histone modification, and chromatin remodeling. DNA methylation patterns are erased in primordial germ cells and in the interval immediately following fertilization. Subsequent developmental reprogramming occurs by de novo methylation and demethylation. Variance in DNA methylation patterns between different cell types is not well understood. Here, using methylated DNA immunoprecipitation and tiling array technology, we have comprehensively analyzed DNA methylation patterns at proximal promoter regions in mouse embryonic stem (ES) cells, ES cell-derived early germ layers (ectoderm, endoderm and mesoderm) and four adult tissues (brain, liver, skeletal muscle and sperm). Most of the methylated regions are methylated across all three germ layers and in the three adult somatic tissues. This commonly methylated gene set is enriched in germ cell-associated genes that are generally transcriptionally inactive in somatic cells. We also compared DNA methylation patterns by global mapping of histone H3 lysine 4/27 trimethylation, and found that gain of DNA methylation correlates with loss of histone H3 lysine 4 trimethylation. Our combined findings indicate that differentiation of ES cells into the three germ layers is accompanied by an increased number of commonly methylated DNA regions and that these tissue-specific alterations in methylation occur for only a small number of genes. DNA methylation at the proximal promoter regions of commonly methylated genes thus appears to be an irreversible mark which functions to fix somatic lineage by repressing the transcription of germ cell-specific genes.

Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi.

PubMed

Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

2009-08-25

In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. In the present study, the role of the Wnt5 genes, Hr-Wnt5alpha (Halocynthia roretzi Wnt5alpha) and Hr-Wnt5beta, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5alpha is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5alpha plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5alpha indicated that a Wnt5alpha-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5alpha works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5alpha and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. The present study highlights the role of the Wnt5alpha signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5alpha functions in a cell-autonomous manner in activation of the Wnt/PCP pathway to polarize the protrusive activity that drives convergent extension.

A model of early human embryonic stem cell differentiation reveals inter- and intracellular changes on transition to squamous epithelium.

PubMed

Galat, Vasiliy; Malchenko, Sergey; Galat, Yekaterina; Ishkin, Alex; Nikolsky, Yuri; Kosak, Steven T; Soares, Bento Marcelo; Iannaccone, Philip; Crispino, John D; Hendrix, Mary J C

2012-05-20

The molecular events leading to human embryonic stem cell (hESC) differentiation are the subject of considerable scrutiny. Here, we characterize an in vitro model that permits analysis of the earliest steps in the transition of hESC colonies to squamous epithelium on basic fibroblast growth factor withdrawal. A set of markers (GSC, CK18, Gata4, Eomes, and Sox17) point to a mesendodermal nature of the epithelial cells with subsequent commitment to definitive endoderm (Sox17, Cdx2, nestin, and Islet1). We assayed alterations in the transcriptome in parallel with the distribution of immunohistochemical markers. Our results indicate that the alterations of tight junctions in pluripotent culture precede the beginning of differentiation. We defined this cell population as "specified," as it is committed toward differentiation. The transitional zone between "specified" pluripotent and differentiated cells displays significant up-regulation of keratin-18 (CK18) along with a decrease in the functional activity of gap junctions and the down-regulation of 2 gap junction proteins, connexin 43 (Cx43) and connexin 45 (Cx45), which is coincidental with substantial elevation of intracellular Ca2+ levels. These findings reveal a set of cellular changes that may represent the earliest markers of in vitro hESC transition to an epithelial phenotype, before the induction of gene expression networks that guide hESC differentiation. Moreover, we hypothesize that these events may be common during the primary steps of hESC commitment to functionally varied epithelial tissue derivatives of different embryological origins.

A Model of Early Human Embryonic Stem Cell Differentiation Reveals Inter- and Intracellular Changes on Transition to Squamous Epithelium

PubMed Central

Malchenko, Sergey; Galat, Yekaterina; Ishkin, Alex; Nikolsky, Yuri; Kosak, Steven T.; Soares, Bento Marcelo; Iannaccone, Philip; Crispino, John D.; Hendrix, Mary J.C.

2012-01-01

The molecular events leading to human embryonic stem cell (hESC) differentiation are the subject of considerable scrutiny. Here, we characterize an in vitro model that permits analysis of the earliest steps in the transition of hESC colonies to squamous epithelium on basic fibroblast growth factor withdrawal. A set of markers (GSC, CK18, Gata4, Eomes, and Sox17) point to a mesendodermal nature of the epithelial cells with subsequent commitment to definitive endoderm (Sox17, Cdx2, nestin, and Islet1). We assayed alterations in the transcriptome in parallel with the distribution of immunohistochemical markers. Our results indicate that the alterations of tight junctions in pluripotent culture precede the beginning of differentiation. We defined this cell population as “specified,” as it is committed toward differentiation. The transitional zone between “specified” pluripotent and differentiated cells displays significant up-regulation of keratin-18 (CK18) along with a decrease in the functional activity of gap junctions and the down-regulation of 2 gap junction proteins, connexin 43 (Cx43) and connexin 45 (Cx45), which is coincidental with substantial elevation of intracellular Ca2+ levels. These findings reveal a set of cellular changes that may represent the earliest markers of in vitro hESC transition to an epithelial phenotype, before the induction of gene expression networks that guide hESC differentiation. Moreover, we hypothesize that these events may be common during the primary steps of hESC commitment to functionally varied epithelial tissue derivatives of different embryological origins. PMID:21861759

Deterministically patterned biomimetic human iPSC-derived hepatic model via rapid 3D bioprinting

PubMed Central

Ma, Xuanyi; Qu, Xin; Zhu, Wei; Li, Yi-Shuan; Yuan, Suli; Zhang, Hong; Liu, Justin; Wang, Pengrui; Lai, Cheuk Sun Edwin; Zanella, Fabian; Feng, Gen-Sheng; Sheikh, Farah; Chien, Shu; Chen, Shaochen

2016-01-01

The functional maturation and preservation of hepatic cells derived from human induced pluripotent stem cells (hiPSCs) are essential to personalized in vitro drug screening and disease study. Major liver functions are tightly linked to the 3D assembly of hepatocytes, with the supporting cell types from both endodermal and mesodermal origins in a hexagonal lobule unit. Although there are many reports on functional 2D cell differentiation, few studies have demonstrated the in vitro maturation of hiPSC-derived hepatic progenitor cells (hiPSC-HPCs) in a 3D environment that depicts the physiologically relevant cell combination and microarchitecture. The application of rapid, digital 3D bioprinting to tissue engineering has allowed 3D patterning of multiple cell types in a predefined biomimetic manner. Here we present a 3D hydrogel-based triculture model that embeds hiPSC-HPCs with human umbilical vein endothelial cells and adipose-derived stem cells in a microscale hexagonal architecture. In comparison with 2D monolayer culture and a 3D HPC-only model, our 3D triculture model shows both phenotypic and functional enhancements in the hiPSC-HPCs over weeks of in vitro culture. Specifically, we find improved morphological organization, higher liver-specific gene expression levels, increased metabolic product secretion, and enhanced cytochrome P450 induction. The application of bioprinting technology in tissue engineering enables the development of a 3D biomimetic liver model that recapitulates the native liver module architecture and could be used for various applications such as early drug screening and disease modeling. PMID:26858399

Generation of functional hepatocyte-like cells from human pluripotent stem cells in a scalable suspension culture.

PubMed

Vosough, Massoud; Omidinia, Eskandar; Kadivar, Mehdi; Shokrgozar, Mohammad-Ali; Pournasr, Behshad; Aghdami, Nasser; Baharvand, Hossein

2013-10-15

Recent advances in human embryonic and induced pluripotent stem cell-based therapies in animal models of hepatic failure have led to an increased appreciation of the need to translate the proof-of-principle concepts into more practical and feasible protocols for scale up and manufacturing of functional hepatocytes. In this study, we describe a scalable stirred-suspension bioreactor culture of functional hepatocyte-like cells (HLCs) from the human pluripotent stem cells (hPSCs). To promote the initial differentiation of hPSCs in a carrier-free suspension stirred bioreactor into definitive endoderm, we used rapamycin for "priming" phase and activin A for induction. The cells were further differentiated into HLCs in the same system. HLCs were characterized and then purified based on their physiological function, the uptake of DiI-acetylated low-density lipoprotein (LDL) by flow cytometry without genetic manipulation or antibody labeling. The sorted cells were transplanted into the spleens of mice with acute liver injury from carbon tetrachloride. The differentiated HLCs had multiple features of primary hepatocytes, for example, the expression patterns of liver-specific marker genes, albumin secretion, urea production, collagen synthesis, indocyanin green and LDL uptake, glycogen storage, and inducible cytochrome P450 activity. They increased the survival rate, engrafted successfully into the liver, and continued to present hepatic function (i.e., albumin secretion after implantation). This amenable scaling up and outlined enrichment strategy provides a new platform for generating functional HLCs. This integrated approach may facilitate biomedical applications of the hPSC-derived hepatocytes.

Generation of chondrocytes from embryonic stem cells.

PubMed

Khillan, Jaspal Singh

2006-01-01

Pluripotent embryonic stem (ES) cells have complete potential for all the primary germ layers, such as ectoderm, mesoderm, and endoderm. However, the cellular and molecular mechanisms that control their lineage-restricted differentiation are not understood. Although embryoid bodies, which are formed because of the spontaneous differentiation of ES cells, have been used to study the differentiation into different cell types, including neurons, chondrocytes, insulin-producing cells, bone-forming cells, hematopoietic cells, and so on, this system has limitations for investigating the upstream events that lead to commitment of cells that occur during the inaccessible period of development. Recent developments in human ES cells have offered a challenge to develop strategies for understanding the basic mechanisms that play a key role in differentiation of stem cell into specific cell types for their applications in regenerative medicine and cell-based therapies. A micromass culture system was developed to induce the differentiation of ES cells into chondrocytes, the cartilage-producing cells, as a model to investigate the upstream events of stem cell differentiation. ES cells were co-cultured with limb bud progenitor cells. A high percentage of differentiated cells exhibit typical morphological characteristics of chondrocytes and express cartilage matrix genes such as collagen type II and proteoglycans, suggesting that signals from the progenitor cells are sufficient to induce ES cells into the chondrogenic lineage. Degeneration of cartilage in the joints is associated with osteoarthritis, which affects the quality of life of human patients. Therefore, the quantitative production of chondrocytes can be a powerful resource to alleviate the suffering of those patients.

Production of cloned and transgenic embryos using buffalo (Bubalus bubalis) embryonic stem cell-like cells isolated from in vitro fertilized and cloned blastocysts.

PubMed

George, Aman; Sharma, Ruchi; Singh, Karn P; Panda, Sudeepta K; Singla, Suresh K; Palta, Prabhat; Manik, Radhaysham; Chauhan, Manmohan S

2011-06-01

Here, we report the isolation and characterization of embryonic stem (ES) cell-like cells from cloned blastocysts, generated using fibroblasts derived from an adult buffalo (BAF). These nuclear transfer embryonic stem cell-like cells (NT-ES) grew in well-defined and dome-shaped colonies. The expression pattern of pluripotency marker genes was similar in both NT-ES and in vitro fertilization (IVF) embryo-derived embryonic stem cell-like cells (F-ES). Upon spontaneous differentiation via embryoid body formation, cells of different morphology were observed, among which predominant were endodermal-like and epithelial-like cell types. The ES cell-like cells could be passaged only mechanically and did not form colonies when plated as single cell suspension at different concentrations. When F-ES cell-like, NT-ES cell-like, and BAF cells of same genotype were used for hand-made cloning (HMC), no significant difference (p > 0.05) was observed in cleavage and blastocyst rate. Following transfer of HMC embryos to synchronized recipients, pregnancies were established only with F-ES cell-like and BAF cell-derived embryos, and one live calf was born from F-ES cell-like cells. Further, when transfected NT-ES cell-like cells and BAF were used for HMC, no significant difference (p > 0.05) was observed between cleavage and blastocyst rate. In conclusion, here we report for the first time the derivation of ES cell-like cells from an adult buffalo, and its genetic modification. We also report the birth of a live cloned calf from buffalo ES cell-like cells.

The accumulation and localization of chalcone synthase in grapevine (Vitis vinifera L.).

PubMed

Wang, Huiling; Wang, Wei; Zhan, JiCheng; Yan, Ailing; Sun, Lei; Zhang, Guojun; Wang, Xiaoyue; Ren, Jiancheng; Huang, Weidong; Xu, Haiying

2016-09-01

Chalcone synthase (CHS, E.C.2.3.1.74) is the first committed enzyme in the flavonoid pathway. Previous studies have primarily focused on the cloning, expression and regulation of the gene at the transcriptional level. Little is yet known about the enzyme accumulation, regulation at protein level, as well as its localization in grapevine. In present study, the accumulation, tissue and subcellular localization of CHS in different grapevine tissues (Vitis vinifera L. Cabernet Sauvignon) were investigated via the techniques of Western blotting, immunohistochemical localization, immunoelectron microscopy and confocal microscopy. The results showed that CHS were mainly accumulated in the grape berry skin, leaves, stem tips and stem phloem, correlated with flavonoids accumulation. The accumulation of CHS is developmental dependent in grape berry skin and flesh. Immunohistochemical analysis revealed that CHS were primarily localized in the exocarp and vascular bundles of the fruits during berry development; in palisade, spongy tissues and vascular bundles of the leaves; in the primary phloem and pith ray in the stems; in the growth point, leaf primordium, and young leaves of leaf buds; and in the endoderm and primary phloem of grapevine roots. Furthermore, at the subcellular level, the cell wall, cytoplasm and nucleus localized patterns of CHS were observed in the grapevine vegetative tissue cells. Results above indicated that distribution of CHS in grapevine was organ-specific and tissue-specific. This work will provide new insight for the biosynthesis and regulation of diverse flavonoid compounds in grapevine. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Genome-wide direct target analysis reveals a role for SHORT-ROOT in root vascular patterning through cytokinin homeostasis.

PubMed

Cui, Hongchang; Hao, Yueling; Kovtun, Mikhail; Stolc, Viktor; Deng, Xing-Wang; Sakakibara, Hitoshi; Kojima, Mikiko

2011-11-01

SHORT-ROOT (SHR) is a key regulator of root growth and development in Arabidopsis (Arabidopsis thaliana). Made in the stele, the SHR protein moves into an adjacent cell layer, where it specifies endodermal cell fate; it is also essential for apical meristem maintenance, ground tissue patterning, vascular differentiation, and lateral root formation. Much has been learned about the mechanism by which SHR controls radial patterning, but how it regulates other aspects of root morphogenesis is still unclear. To dissect the SHR developmental pathway, we have determined the genome-wide locations of SHR direct targets using a chromatin immunoprecipitation followed by microarray analysis method. K-means clustering analysis not only identified additional quiescent center-specific SHR targets but also revealed a direct role for SHR in gene regulation in the pericycle and xylem. Using cell type-specific markers, we showed that in shr, the phloem and the phloem-associated pericycle expanded, whereas the xylem and xylem-associated pericycle diminished. Interestingly, we found that cytokinin level was elevated in shr and that exogenous cytokinin conferred a shr-like vascular patterning phenotype in wild-type root. By chromatin immunoprecipitation-polymerase chain reaction and reverse transcription-polymerase chain reaction assays, we showed that SHR regulates cytokinin homeostasis by directly controlling the transcription of cytokinin oxidase 3, a cytokinin catabolism enzyme preferentially expressed in the stele. Finally, overexpression of a cytokinin oxidase in shr alleviated its vascular patterning defect. On the basis of these results, we suggest that one mechanism by which SHR controls vascular patterning is the regulation of cytokinin homeostasis.

Deterministically patterned biomimetic human iPSC-derived hepatic model via rapid 3D bioprinting.

PubMed

Ma, Xuanyi; Qu, Xin; Zhu, Wei; Li, Yi-Shuan; Yuan, Suli; Zhang, Hong; Liu, Justin; Wang, Pengrui; Lai, Cheuk Sun Edwin; Zanella, Fabian; Feng, Gen-Sheng; Sheikh, Farah; Chien, Shu; Chen, Shaochen

2016-02-23

The functional maturation and preservation of hepatic cells derived from human induced pluripotent stem cells (hiPSCs) are essential to personalized in vitro drug screening and disease study. Major liver functions are tightly linked to the 3D assembly of hepatocytes, with the supporting cell types from both endodermal and mesodermal origins in a hexagonal lobule unit. Although there are many reports on functional 2D cell differentiation, few studies have demonstrated the in vitro maturation of hiPSC-derived hepatic progenitor cells (hiPSC-HPCs) in a 3D environment that depicts the physiologically relevant cell combination and microarchitecture. The application of rapid, digital 3D bioprinting to tissue engineering has allowed 3D patterning of multiple cell types in a predefined biomimetic manner. Here we present a 3D hydrogel-based triculture model that embeds hiPSC-HPCs with human umbilical vein endothelial cells and adipose-derived stem cells in a microscale hexagonal architecture. In comparison with 2D monolayer culture and a 3D HPC-only model, our 3D triculture model shows both phenotypic and functional enhancements in the hiPSC-HPCs over weeks of in vitro culture. Specifically, we find improved morphological organization, higher liver-specific gene expression levels, increased metabolic product secretion, and enhanced cytochrome P450 induction. The application of bioprinting technology in tissue engineering enables the development of a 3D biomimetic liver model that recapitulates the native liver module architecture and could be used for various applications such as early drug screening and disease modeling.

Expression pattern of pluripotent markers in different embryonic developmental stages of buffalo (Bubalus bubalis) embryos and putative embryonic stem cells generated by parthenogenetic activation.

PubMed

Singh, Karn P; Kaushik, Ramakant; Garg, Veena; Sharma, Ruchi; George, Aman; Singh, Manoj K; Manik, Radhey S; Palta, Prabhat; Singla, Suresh K; Chauhan, Manmohan S

2012-12-01

In this study, we describe the production of buffalo parthenogenetic blastocysts and subsequent isolation of parthenogenetic embryonic stem cell (PGESC)-like cells. PGESC colonies exhibited dome-shaped morphology and were clearly distinguishable from the feeder layer cells. Different stages of development of parthenogenetic embryos and derived embryonic stem cell (ESC)-like cells expressed key ESC-specific markers, including OCT-4, NANOG, SOX-2, FOXD3, REX-1, STAT-3, TELOMERASE, NUCLEOSTEMIN, and cMYC. Immunofluorescence-based studies revealed that the PGESCs were positive for surface-based pluripotent markers, viz., SSEA-3, SSEA-4, TRA 1-80, TRA 1-60, CD-9, and CD-90 and exhibited high alkaline phosphatase (ALP) activity. PGEC cell-like cells formed embryoid body (EB)-like structures in hanging drop cultures and when cultured for extended period of time spontaneously differentiated into derivatives of three embryonic germ layers as confirmed by RT-PCR for ectodermal (CYTOKERATIN8, NF-68), mesodermal (MSX1, BMP-4, ASA), and endodermal markers (AFP, HNF-4, GATA-4). Differentiation of PGESCs toward the neuronal lineage was successfully directed by supplementation of serum-containing media with retinoic acid. Our results indicate that the isolated ESC-like cells from parthenogenetic blastocyst hold properties of ESCs and express markers of pluripotency. The pluripotency markers were also expressed by early cleavage-stage of buffalo embryos.

Species specificity in cell-substrate interactions in medusae.

PubMed

Schmid, V; Bally, A

1988-10-01

A new system is described for the study of ECM-tissue interactions, using the ECM (called mesogloea) of various cnidarians and isolated striated muscle and endodermal tissue of jellyfish. The mesogloea consists mainly of water and collagen. It is present in all cnidarians and can be isolated without enzyme treatment. It can be used as a substrate to which cells and tissues adhere and on which they spread and migrate. Tissues of striated muscle and endoderm adhere and spread not only on mesogloea from regions they normally cover, but also from other regions of the animal. However, adhesion and spreading are highly species-specific. Species-specific adhesion is found throughout the whole mass of mesogloea even at regions where cells do not occur naturally. The cell adhesion factor can be extracted from the mesogloea so that the mesogloea no longer shows any cell adhesion properties. The extract consists mainly of a cysteine-containing collagen.

Defining the site of light perception and initiation of phototropism in Arabidopsis.

PubMed

Preuten, Tobias; Hohm, Tim; Bergmann, Sven; Fankhauser, Christian

2013-10-07

Phototropism is an adaptive response allowing plants to optimize photosynthetic light capture. This is achieved by asymmetric growth between the shaded and lit sides of the stimulated organ. In grass seedlings, the site of phototropin-mediated light perception is distinct from the site of bending; however, in dicotyledonous plants (e.g., Arabidopsis), spatial aspects of perception remain debatable. We use morphological studies and genetics to show that phototropism can occur in the absence of the root, lower hypocotyl, hypocotyl apex, and cotyledons. Tissue-specific expression of the phototropin1 (phot1) photoreceptor demonstrates that light sensing occurs in the upper hypocotyl and that expression of phot1 in the hypocotyl elongation zone is sufficient to enable a normal phototropic response. Moreover, we show that efficient phototropism occurs when phot1 is expressed from endodermal, cortical, or epidermal cells and that its local activation rapidly leads to a global response throughout the seedling. We propose that spatial aspects in the steps leading from light perception to growth reorientation during phototropism differ between grasses and dicots. These results are important to properly interpret genetic experiments and establish a model connecting light perception to the growth response, including cellular and morphological aspects. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of Aminoglycoside Antibiotics on Human Embryonic Stem Cell Viability during Differentiation In Vitro

PubMed Central

Varghese, Divya S.; Parween, Shama; Ardah, Mustafa T.; Emerald, Bright Starling

2017-01-01

Human embryonic stem cells (hESCs) are being used extensively in array of studies to understand different mechanisms such as early human embryogenesis, drug toxicity testing, disease modeling, and cell replacement therapy. The protocols for the directed differentiation of hESCs towards specific cell types often require long-term cell cultures. To avoid bacterial contamination, these protocols include addition of antibiotics such as pen-strep and gentamicin. Although aminoglycosides, streptomycin, and gentamicin have been shown to cause cytotoxicity in various animal models, the effect of these antibiotics on hESCs is not clear. In this study, we found that antibiotics, pen-strep, and gentamicin did not affect hESC cell viability or expression of pluripotency markers. However, during directed differentiation towards neural and hepatic fate, significant cell death was noted through the activation of caspase cascade. Also, the expression of neural progenitor markers Pax6, Emx2, Otx2, and Pou3f2 was significantly reduced suggesting that gentamicin may adversely affect early embryonic neurogenesis whereas no effect was seen on the expression of endoderm or hepatic markers during differentiation. Our results suggest that the use of antibiotics in cell culture media for the maintenance and differentiation of hESCs needs thorough investigation before use to avoid erroneous results. PMID:29147115

Cell Expansion During Directed Differentiation of Stem Cells Toward the Hepatic Lineage.

PubMed

Raju, Ravali; Chau, David; Cho, Dong Seong; Park, Yonsil; Verfaillie, Catherine M; Hu, Wei-Shou

2017-02-15

The differentiation of human pluripotent stem cells toward the hepatocyte lineage can potentially provide an unlimited source of functional hepatocytes for transplantation and extracorporeal bioartificial liver applications. It is anticipated that the quantities of cells needed for these applications will be in the order of 10 9 -10 10 cells, because of the size of the liver. An ideal differentiation protocol would be to enable directed differentiation to the hepatocyte lineage with simultaneous cell expansion. We introduced a cell expansion stage after the commitment of human embryonic stem cells to the endodermal lineage, to allow for at least an eightfold increase in cell number, with continuation of cell maturation toward the hepatocyte lineage. The progressive changes in the transcriptome were measured by expression array, and the expression dynamics of certain lineage markers was measured by mass cytometry during the differentiation and expansion process. The findings revealed that while cells were expanding they were also capable of progressing in their differentiation toward the hepatocyte lineage. In addition, our transcriptome, protein and functional studies, including albumin secretion, drug-induced CYP450 expression and urea production, all indicated that the hepatocyte-like cells obtained with or without cell expansion are very similar. This method of simultaneous cell expansion and hepatocyte differentiation should facilitate obtaining large quantities of cells for liver cell applications.

Hepatogenic and neurogenic differentiation of bone marrow mesenchymal stem cells from abattoir-derived bovine fetuses

PubMed Central

2014-01-01

Background Mesenchymal stem cells (MSC) are multipotent progenitor cells characterized by their ability to both self-renew and differentiate into tissues of mesodermal origin. The plasticity or transdifferentiation potential of MSC is not limited to mesodermal derivatives, since under appropriate cell culture conditions and stimulation by bioactive factors, MSC have also been differentiated into endodermal (hepatocytes) and neuroectodermal (neurons) cells. The potential of MSC for hepatogenic and neurogenic differentiation has been well documented in different animal models; however, few reports are currently available on large animal models. In the present study we sought to characterize the hepatogenic and neurogenic differentiation and multipotent potential of bovine MSC (bMSC) isolated from bone marrow (BM) of abattoir-derived fetuses. Results Plastic-adherent bMSC isolated from fetal BM maintained a fibroblast-like morphology under monolayer culture conditions. Flow cytometric analysis demonstrated that bMSC populations were positive for MSC markers CD29 and CD73 and pluripotency markers OCT4 and NANOG; whereas, were negative for hematopoietic markers CD34 and CD45. Levels of mRNA of hepatic genes α-fetoprotein (AFP), albumin (ALB), alpha1 antitrypsin (α1AT), connexin 32 (CNX32), tyrosine aminotransferase (TAT) and cytochrome P450 (CYP3A4) were up-regulated in bMSC during a 28-Day period of hepatogenic differentiation. Functional analyses in differentiated bMSC cultures evidenced an increase (P < 0.05) in albumin and urea production and glycogen storage. bMSC cultured under neurogenic conditions expressed NESTIN and MAP2 proteins at 24 h of culture; whereas, at 144 h also expressed TRKA and PrPC. Levels of MAP2 and TRKA mRNA were up-regulated at the end of the differentiation period. Conversely, bMSC expressed lower levels of NANOG mRNA during both hepatogenic and neurogenic differentiation processes. Conclusion The expression patterns of linage-specific markers and the production of functional metabolites support the potential for hepatogenic and neurogenic differentiation of bMSC isolated from BM of abattoir-derived fetuses. The simplicity of isolation and the potential to differentiate into a wide variety of cell lineages lays the foundation for bMSC as an interesting alternative for investigation in MSC biology and eventual applications for regenerative therapy in veterinary medicine. PMID:25011474

Multi-functionality and plasticity characterize epithelial cells in Hydra

PubMed Central

Buzgariu, W; Al Haddad, S; Tomczyk, S; Wenger, Y; Galliot, B

2015-01-01

Epithelial sheets, a synapomorphy of all metazoans but porifers, are present as 2 layers in cnidarians, ectoderm and endoderm, joined at their basal side by an extra-cellular matrix named mesoglea. In the Hydra polyp, epithelial cells of the body column are unipotent stem cells that continuously self-renew and concomitantly express their epitheliomuscular features. These multifunctional contractile cells maintain homeostasis by providing a protective physical barrier, by digesting nutrients, by selecting a stable microbiota, and by rapidly closing wounds. In addition, epithelial cells are highly plastic, supporting the adaptation of Hydra to physiological and environmental changes, such as long starvation periods where survival relies on a highly dynamic autophagy flux. Epithelial cells also play key roles in developmental processes as evidenced by the organizer activity they develop to promote budding and regeneration. We propose here an integrative view of the homeostatic and developmental aspects of epithelial plasticity in Hydra. PMID:26716072

Malignant ovarian germ cell tumor - role of surgical staging and gonadal dysgenesis.

PubMed

Lin, Ken Y; Bryant, Stefanie; Miller, David S; Kehoe, Siobhan M; Richardson, Debra L; Lea, Jayanthi S

2014-07-01

To evaluate the effect of comprehensive surgical staging and gonadal dysgenesis on the outcomes of patients with malignant ovarian germ cell tumor. We performed a retrospective review of patients with ovarian germ cell tumors who were treated at our institution between 1976 and 2012. Malignant ovarian germ cell tumors (MOGCTs) were identified in 50 females. The median age was 24 years (range 13 to 49). Of all MOGCT patients, 42% had dysgerminoma, 20% immature teratoma, 16% endodermal sinus tumor, and 22% mixed germ cell tumor. Univariate analyses revealed that the lack of surgical staging (p=0.048) and endodermal sinus tumor (p=0.0085) were associated with disease recurrence, while age at diagnosis, ethnicity, and stage of the disease were not. Multivariate analyses revealed that the lack of surgical staging (p=0.029) and endodermal sinus tumor (p=0.016) were independently associated with disease recurrence. In addition, 7 patients (14%) had 46 XY karyotype, including 6 with pure dysgerminoma and 1 with mixed germ cell tumor. Five had Swyer syndrome and 2 had complete androgen insensitivity syndrome. Concurrent gonadoblastoma was found in 5 of the patients. No difference was found in the mean age at presentation, stage distribution, or recurrence rate for MOGCT patients with or without XY phenotype. Comprehensive surgical staging was associated with a lower rate of recurrence. Fourteen percent of phenotypic females with MOGCT and 29% of those with dysgerminoma had XY karyotype. The clinical outcome of these patients is similar to that of MOGCT patients with XX karyotype. Published by Elsevier Inc.

T-18, a stemonamide synthetic intermediate inhibits Pim kinase activity and induces cell apoptosis, acting as a potent anticancer drug.

PubMed

Wang, Zhen; Li, Xing-Min; Shang, Kun; Zhang, Peng; Wang, Chao-Fu; Xin, Yu-Hu; Zhou, Lu; Li, Ying-Yi

2013-03-01

Pim-3 kinase has been shown to be aberrantly expressed in premalignant and malignant lesions of endoderm-derived organs such as the liver, pancreas, colon and stomach. Pim-3 kinase inactivates the Bad protein, a proapoptotic molecule, and improves the expression of Bcl-xL, an antiapoptotic molecule, to promote cell proliferation. Thus, blocking Pim-3 kinase activity may be a new strategy for the treatment of pancreatic cancer. In this study, we screened low molecular compounds and observed that the stemonamide synthetic intermediate, T-18, potently inhibited Pim kinase activity. Moreover, T-18 inhibited the proliferation of human pancreatic, as well as that of hepatocellular and colon cancer cells in vitro. It also induced the apoptosis of human pancreatic carcinoma cells in vitro by decreasing the levels of phospho-Ser112-Bad; the levels of Pim-3 kinase and total Bad protein were not altered. Furthermore, T-18 inhibited the growth of human pancreatic cancer cells in nude mice without apparent adverse effects when the tumor was palpable. These observations indicate that stemonamide synthetic intermediates may be novel drugs for the treatment of gastrointestinal cancers, particularly pancreatic cancer.

A branching morphogenesis program governs embryonic growth of the thyroid gland

PubMed Central

Liang, Shawn; Johansson, Ellen; Barila, Guillermo; Altschuler, Daniel L.; Fagman, Henrik

2018-01-01

ABSTRACT The developmental program that regulates thyroid progenitor cell proliferation is largely unknown. Here, we show that branching-like morphogenesis is a driving force to attain final size of the embryonic thyroid gland in mice. Sox9, a key factor in branching organ development, distinguishes Nkx2-1+ cells in the thyroid bud from the progenitors that originally form the thyroid placode in anterior endoderm. As lobes develop the thyroid primordial tissue branches several generations. Sox9 and Fgfr2b are co-expressed distally in the branching epithelium prior to folliculogenesis. The thyroid in Fgf10 null mutants has a normal shape but is severely hypoplastic. Absence of Fgf10 leads to defective branching and disorganized angiofollicular units although Sox9/Fgfr2b expression and the ability of cells to differentiate and form nascent follicles are not impaired. These findings demonstrate a novel mechanism of thyroid development reminiscent of the Fgf10-Sox9 program that characterizes organogenesis in classical branching organs, and provide clues to aid understanding of how the endocrine thyroid gland once evolved from an exocrine ancestor present in the invertebrate endostyle. PMID:29361553

A branching morphogenesis program governs embryonic growth of the thyroid gland.

PubMed

Liang, Shawn; Johansson, Ellen; Barila, Guillermo; Altschuler, Daniel L; Fagman, Henrik; Nilsson, Mikael

2018-01-25

The developmental program that regulates thyroid progenitor cell proliferation is largely unknown. Here, we show that branching-like morphogenesis is a driving force to attain final size of the embryonic thyroid gland in mice. Sox9, a key factor in branching organ development, distinguishes Nkx2-1 + cells in the thyroid bud from the progenitors that originally form the thyroid placode in anterior endoderm. As lobes develop the thyroid primordial tissue branches several generations. Sox9 and Fgfr2b are co-expressed distally in the branching epithelium prior to folliculogenesis. The thyroid in Fgf10 null mutants has a normal shape but is severely hypoplastic. Absence of Fgf10 leads to defective branching and disorganized angiofollicular units although Sox9/Fgfr2b expression and the ability of cells to differentiate and form nascent follicles are not impaired. These findings demonstrate a novel mechanism of thyroid development reminiscent of the Fgf10-Sox9 program that characterizes organogenesis in classical branching organs, and provide clues to aid understanding of how the endocrine thyroid gland once evolved from an exocrine ancestor present in the invertebrate endostyle. © 2018. Published by The Company of Biologists Ltd.

Sox9 overexpression in uterine epithelia induces endometrial gland hyperplasia

PubMed Central

Gonzalez, Gabriel; Mehra, Shyamin; Wang, Ying; Akiyama, Haruhiko

2016-01-01

SOX9 is a high mobility group transcription factor that is required in many biological processes, including cartilage differentiation, endoderm progenitor maintenance, hair differentiation, and testis determination. SOX9 has also been linked to colorectal, prostate, and lung cancer. We found that SOX9 is expressed in the epithelium of the adult mouse and human uterus, predominantly marking the uterine glands. To determine if SOX9 plays a role in the development of endometrial cancer we overexpressed Sox9 in the uterine epithelium using a progesterone receptor-Cre mouse model. Sox9 overexpression in the uterine epithelium led to the formation of simple and complex cystic glandular structures in the endometrium of aged-females. Histological analysis revealed that these structures appeared morphologically similar to structures present in patients with endometrial hyperplastic lesions and endometrial polyps that are thought to be precursors of endometrial cancer. The molecular mechanisms that cause the glandular epithelium to become hyperplastic, leading to endometrial cancer are still poorly understood. These findings indicate that chronic overexpression of Sox9 in the uterine epithelium can induce the development of endometrial hyperplastic lesions. Thus, SOX9 expression may be a factor in the formation of endometrial cancer. PMID:27262401

The maintenance of pluripotency following laser direct-write of mouse embryonic stem cells.

PubMed

Raof, Nurazhani Abdul; Schiele, Nathan R; Xie, Yubing; Chrisey, Douglas B; Corr, David T

2011-03-01

The ability to precisely pattern embryonic stem (ES) cells in vitro into predefined arrays/geometries may allow for the recreation of a stem cell niche for better understanding of how cellular microenvironmental factors govern stem cell maintenance and differentiation. In this study, a new gelatin-based laser direct-write (LDW) technique was utilized to deposit mouse ES cells into defined arrays of spots, while maintaining stem cell pluripotency. Results obtained from these studies showed that ES cells were successfully printed into specific patterns and remained viable. Furthermore, ES cells retained the expression of Oct4 in nuclei after LDW, indicating that the laser energy did not affect their maintenance of an undifferentiated state. The differentiation potential of mouse ES cells after LDW was confirmed by their ability to form embryoid bodies (EBs) and to spontaneously become cell lineages representing all three germ layers, revealed by the expression of marker proteins of nestin (ectoderm), Myf-5 (mesoderm) and PDX-1 (endoderm), after 7 days of cultivation. Gelatin-based LDW provides a new avenue for stem cell patterning, with precision and control of the cellular microenvironment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Chromatin remodeling agent trichostatin A: a key-factor in the hepatic differentiation of human mesenchymal stem cells derived of adult bone marrow

PubMed Central

Snykers, Sarah; Vanhaecke, Tamara; De Becker, Ann; Papeleu, Peggy; Vinken, Mathieu; Van Riet, Ivan; Rogiers, Vera

2007-01-01

Background The capability of human mesenchymal stem cells (hMSC) derived of adult bone marrow to undergo in vitro hepatic differentiation was investigated. Results Exposure of hMSC to a cocktail of hepatogenic factors [(fibroblast growth factor-4 (FGF-4), hepatocyte growth factor (HGF), insulin-transferrin-sodium-selenite (ITS) and dexamethasone)] failed to induce hepatic differentiation. Sequential exposure to these factors (FGF-4, followed by HGF, followed by HGF+ITS+dexamethasone), however, resembling the order of secretion during liver embryogenesis, induced both glycogen-storage and cytokeratin (CK)18 expression. Additional exposure of the cells to trichostatin A (TSA) considerably improved endodermal differentiation, as evidenced by acquisition of an epithelial morphology, chronological expression of hepatic proteins, including hepatocyte-nuclear factor (HNF)-3β, alpha-fetoprotein (AFP), CK18, albumin (ALB), HNF1α, multidrug resistance-associated protein (MRP)2 and CCAAT-enhancer binding protein (C/EBP)α, and functional maturation, i.e. upregulated ALB secretion, urea production and inducible cytochrome P450 (CYP)-dependent activity. Conclusion hMSC are able to undergo mesenchymal-to-epithelial transition. TSA is hereby essential to promote differentiation of hMSC towards functional hepatocyte-like cells. PMID:17407549

RBP-Jκ-Dependent Notch Signaling Is Dispensable for Mouse Early Embryonic Development

PubMed Central

Souilhol, Céline; Cormier, Sarah; Tanigaki, Kenji; Babinet, Charles; Cohen-Tannoudji, Michel

2006-01-01

The Notch signaling pathway is an evolutionarily conserved signaling system which has been shown to be essential in cell fate specification and in numerous aspects of embryonic development in all metazoans thus far studied. We recently demonstrated that several components of the Notch signaling pathway, including the four Notch receptors and their five ligands known in mammals, are expressed in mouse oocytes, in mouse preimplantation embryos, or both. This suggested a possible implication of the Notch pathway in the first cell fate specification of the dividing mouse embryo, which results in the formation of the blastocyst. To address this issue directly, we generated zygotes in which both the maternal and the zygotic expression of Rbpsuh, a key element of the core Notch signaling pathway, were abrogated. We find that such zygotes give rise to blastocysts which implant and develop normally. Nevertheless, after gastrulation, these embryos die around midgestation, similarly to Rbpsuh-null mutants. This demonstrates that the RBP-Jκ-dependent pathway, otherwise called the canonical Notch pathway, is dispensable for blastocyst morphogenesis and the establishment of the three germ layers, ectoderm, endoderm, and mesoderm. These results are discussed in the light of recent observations which have challenged this conclusion. PMID:16782866

RBP-Jkappa-dependent notch signaling is dispensable for mouse early embryonic development.

PubMed

Souilhol, Céline; Cormier, Sarah; Tanigaki, Kenji; Babinet, Charles; Cohen-Tannoudji, Michel

2006-07-01

The Notch signaling pathway is an evolutionarily conserved signaling system which has been shown to be essential in cell fate specification and in numerous aspects of embryonic development in all metazoans thus far studied. We recently demonstrated that several components of the Notch signaling pathway, including the four Notch receptors and their five ligands known in mammals, are expressed in mouse oocytes, in mouse preimplantation embryos, or both. This suggested a possible implication of the Notch pathway in the first cell fate specification of the dividing mouse embryo, which results in the formation of the blastocyst. To address this issue directly, we generated zygotes in which both the maternal and the zygotic expression of Rbpsuh, a key element of the core Notch signaling pathway, were abrogated. We find that such zygotes give rise to blastocysts which implant and develop normally. Nevertheless, after gastrulation, these embryos die around midgestation, similarly to Rbpsuh-null mutants. This demonstrates that the RBP-Jkappa-dependent pathway, otherwise called the canonical Notch pathway, is dispensable for blastocyst morphogenesis and the establishment of the three germ layers, ectoderm, endoderm, and mesoderm. These results are discussed in the light of recent observations which have challenged this conclusion.

Cell proliferation in mammalian gastrulation: the ventral node and notochord are relatively quiescent.

PubMed

Bellomo, D; Lander, A; Harragan, I; Brown, N A

1996-04-01

During gastrulation, the node of the mammalian embryo appears to be an organising centre, homologous to Hensen's node in the chick and the dorsal lip of the amphibian blastopore. In addition, the node serves as a precursor population for the head process, notochord and foregut endoderm. We have studied node architecture and cell morphology by electron microscopy, and cell proliferation using bromodeoxyuridine incorporation and mitotic counts. The dorsal (ectodermal) and ventral (endodermal) components of the node are two distinct populations, separated by a basement membrane. The ventral node, contiguous with the head process, is characterised by a relatively low proliferation rate, with only approximately 10% of cells incorporating BrdU over 4 hr, compared to > 95% in surrounding mesodermal and ectodermal tissues. This is the case from the beginning of node formation, at the no-allantoic-bud stage, until the 7 somite stage, and is not compatible with the idea that the ventral node is a stem cell population. The dorsal node is highly proliferative, its rate of division being indistinguishable from the neurectoderm, with which it is contiguous. In the ventral node, two regions can be recognised: cells in the "pit" are columnar and all monociliated; around them lies a "crown" of cells arranged radially in a horseshoe shape and less often ciliated. Node derivatives share common features with the ventral node; the head process and the notochord are relatively quiescent; and some head process cells are also monociliated. Node and head process monocilia are immotile and appear to be associated with non-proliferation. We suggest that the ventral node contains all the properties of the organiser, while the dorsal node is indistinct from the surrounding epiblast. The cranial end of the foregut pouch, the thyroid diverticulum, and the promyocardium of early somite stage embryos are also areas of low cell division. All the described regions of relative quiescence are sites of expression of members of the TGF beta family, which may be involved in maintaining non-proliferation.

Rfx6 Directs Islet Formation and Insulin Production in Mice and Humans

PubMed Central

Smith, Stuart B.; Qu, Hui-Qi; Taleb, Nadine; Kishimoto, Nina; Scheel, David W.; Lu, Yang; Patch, Ann-Marie; Grabs, Rosemary; Wang, Juehu; Lynn, Francis C.; Miyatsuka, Takeshi; Mitchell, John; Seerke, Rina; Désir, Julie; Eijnden, Serge Vanden; Abramowicz, Marc; Kacet, Nadine; Weill, Jacques; Renard, Marie-Éve; Gentile, Mattia; Hansen, Inger; Dewar, Ken; Hattersley, Andrew T.; Wang, Rennian; Wilson, Maria E.; Johnson, Jeffrey D.; Polychronakos, Constantin; German, Michael S.

2009-01-01

Insulin from the β-cells of the pancreatic islets of Langerhans controls energy homeostasis in vertebrates, and its deficiency causes diabetes mellitus. During embryonic development, the transcription factor Neurogenin3 initiates the differentiation of the β-cells and other islet cell types from pancreatic endoderm, but the genetic program that subsequently completes this differentiation remains incompletely understood. Here we show that the transcription factor Rfx6 directs islet cell differentiation downstream of Neurogenin3. Mice lacking Rfx6 failed to generate any of the normal islet cell types except for pancreatic-polypeptide-producing cells. In human infants with a similar autosomal recessive syndrome of neonatal diabetes, genetic mapping and subsequent sequencing identified mutations in the human RFX6 gene. These studies demonstrate a unique position for Rfx6 in the hierarchy of factors that coordinate pancreatic islet development in both mice and humans. Rfx6 could prove useful in efforts to generate β-cells for patients with diabetes. PMID:20148032

Cardiogenic programming of human pluripotent stem cells by dose-controlled activation of EOMES.

PubMed

Pfeiffer, Martin J; Quaranta, Roberto; Piccini, Ilaria; Fell, Jakob; Rao, Jyoti; Röpke, Albrecht; Seebohm, Guiscard; Greber, Boris

2018-01-30

Master cell fate determinants are thought to induce specific cell lineages in gastrulation by orchestrating entire gene programs. The T-box transcription factor EOMES (eomesodermin) is crucially required for the development of the heart-yet it is equally important for endoderm specification suggesting that it may act in a context-dependent manner. Here, we define an unrecognized interplay between EOMES and the WNT signaling pathway in controlling cardiac induction by using loss and gain-of-function approaches in human embryonic stem cells. Dose-dependent EOMES induction alone can fully replace a cocktail of signaling molecules otherwise essential for the specification of cardiogenic mesoderm. Highly efficient cardiomyocyte programming by EOMES mechanistically involves autocrine activation of canonical WNT signaling via the WNT3 ligand, which necessitates a shutdown of this axis at a subsequent stage. Our findings provide insights into human germ layer induction and bear biotechnological potential for the robust production of cardiomyocytes from engineered stem cells.

A new classification system for congenital laryngeal cysts.

PubMed

Forte, Vito; Fuoco, Gabriel; James, Adrian

2004-06-01

A new classification system for congenital laryngeal cysts based on the extent of the cyst and on the embryologic tissue of origin is proposed. Retrospective chart review. The charts of 20 patients with either congenital or acquired laryngeal cysts that were treated surgically between 1987 and 2002 at the Hospital for Sick Children, Toronto were retrospectively reviewed. Clinical presentation, radiologic findings, surgical management, histopathology, and outcome were recorded. A new classification system is proposed to better appreciate the origin of these cysts and to guide in their successful surgical management. Fourteen of the supraglottic and subglottic simple mucous retention cysts posed no diagnostic or therapeutic challenge and were treated successfully by a single endoscopic excision or marsupialization. The remaining six patients with congenital cysts in the study were deemed more complex, and all required open surgical procedures for cure. On the basis of the analysis of the data of these patients, a new classification of congenital laryngeal cysts is proposed. Type I cysts are confined to the larynx, the cyst wall composed of endodermal elements only, and can be managed endoscopically. Type II cysts extend beyond the confines of the larynx and require an external approach. The Type II cysts are further subclassified histologically on the basis of the embryologic tissue of origin: IIa, composed of endoderm only and IIb, containing endodermal and mesodermal elements (epithelium and cartilage) in the wall of the cyst. A new classification system for congenital laryngeal cysts is proposed on the basis of the extent of the cyst and the embryologic tissue of origin. This classification can help guide the surgeon with initial management and help us better understand the origin of these cysts.

Inconsistent formation and nonfunction of insulin-positive cells from pancreatic endoderm derived from human embryonic stem cells in athymic nude rats.

PubMed

Matveyenko, Aleksey V; Georgia, Senta; Bhushan, Anil; Butler, Peter C

2010-11-01

Embryonic stem cell therapy has been proposed as a therapeutic strategy to restore β-cell mass and function in T1DM. Recently, a group from Novocell (now ViaCyte) reported successful development of glucose-responsive islet-like structures after implantation of pancreatic endoderm (PE) derived from human embryonic stem cells (hESC) into immune-deficient mice. Our objective was to determine whether implantation of hESC-derived pancreatic endoderm from Novocell into athymic nude rats results in development of viable glucose-responsive pancreatic endocrine tissue. Athymic nude rats were implanted with PE derived from hESC either via implantation into the epididymal fat pads or by subcutaneous implantation into TheraCyte encapsulation devices for 20 wk. Blood glucose, weight, and human insulin/C-peptide secretion were monitored by weekly blood draws. Graft β-cell function was assessed by a glucose tolerance test, and graft morphology was assessed by immunohistochemistry and immunofluorescence. At 20 wk postimplantation, epididymal fat-implanted PE progressed to develop islet-like structures in 50% of implants, with a mean β-cell fractional area of 0.8 ± 0.3%. Human C-peptide and insulin were detectable, but at very low levels (C-peptide = 50 ± 26 pmol/l and insulin = 15 ± 7 pmol/l); however, there was no increase in human C-peptide/insulin levels after glucose challenge. There was no development of viable pancreatic tissue or meaningful secretory function when human PE was implanted in the TheraCyte encapsulation devices. These data confirm that islet-like structures develop from hESC differentiated to PE by the protocol developed by NovoCell. However, the extent of endocrine cell formation and secretory function is not yet sufficient to be clinically relevant.

Inconsistent formation and nonfunction of insulin-positive cells from pancreatic endoderm derived from human embryonic stem cells in athymic nude rats

PubMed Central

Matveyenko, Aleksey V.; Georgia, Senta; Bhushan, Anil

2010-01-01

Embryonic stem cell therapy has been proposed as a therapeutic strategy to restore β-cell mass and function in T1DM. Recently, a group from Novocell (now ViaCyte) reported successful development of glucose-responsive islet-like structures after implantation of pancreatic endoderm (PE) derived from human embryonic stem cells (hESC) into immune-deficient mice. Our objective was to determine whether implantation of hESC-derived pancreatic endoderm from Novocell into athymic nude rats results in development of viable glucose-responsive pancreatic endocrine tissue. Athymic nude rats were implanted with PE derived from hESC either via implantation into the epididymal fat pads or by subcutaneous implantation into TheraCyte encapsulation devices for 20 wk. Blood glucose, weight, and human insulin/C-peptide secretion were monitored by weekly blood draws. Graft β-cell function was assessed by a glucose tolerance test, and graft morphology was assessed by immunohistochemistry and immunofluorescence. At 20 wk postimplantation, epididymal fat-implanted PE progressed to develop islet-like structures in 50% of implants, with a mean β-cell fractional area of 0.8 ± 0.3%. Human C-peptide and insulin were detectable, but at very low levels (C-peptide = 50 ± 26 pmol/l and insulin = 15 ± 7 pmol/l); however, there was no increase in human C-peptide/insulin levels after glucose challenge. There was no development of viable pancreatic tissue or meaningful secretory function when human PE was implanted in the TheraCyte encapsulation devices. These data confirm that islet-like structures develop from hESC differentiated to PE by the protocol developed by NovoCell. However, the extent of endocrine cell formation and secretory function is not yet sufficient to be clinically relevant. PMID:20587750

The avian prechordal head region: a morphological study.

PubMed Central

Seifert, R; Jacob, M; Jacob, H J

1993-01-01

The axial mesoderm of the anterior head region was investigated in young chick and quail embryos by light and electron microscopy. Semithin sections showed that the axial head mesoderm consists of the head process and prechordal mesoderm. At the anterior end of the prechordal mesoderm, a group of columnar epithelial cells formed a pit-like structure. The bases of these columnar cells extended to the neural plate, thus limiting the prechordal mesoderm anteriorly. The cells lining the pit-like structure at its anterior end joined a cell accumulation made up of cells of mesenchymal character. Electron microscopy revealed that the columnar cells forming the pit-like structure were covered by a basal lamina which was discontinuous on its anterior aspect. No basal lamina was recognisable between the columnar epithelial cells and mesenchymal cells joining them anteriorly. The columnar epithelial cells bordering the prechordal mesoderm anteriorly were therefore assumed to be part of the endodermal germ layer. In agreement with the findings of other authors, it is proposed to term these axially located columnar cells of the endoderm the prechordal plate and to distinguish them from the prechordal mesoderm arising during gastrulation. For the mesenchymal cell accumulation anterior to the prechordal plate, participation in the formation of the prosencephalic mesenchyme is assumed. This implies that the definitive endodermal germ layer, like the ectodermal one represented by the neural crest, may also be able to contribute to mesenchyme formation in the head. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 PMID:8270478

Sonic Hedgehog in pancreatic cancer: From bench to bedside, then back to the bench

PubMed Central

Rosow, David E.; Liss, Andrew S.; Strobel, Oliver; Fritz, Stefan; Bausch, Dirk; Valsangkar, Nakul P.; Alsina, Janivette; Kulemann, Birte; Park, Joo Kyung; Yamaguchi, Junpei; LaFemina, Jennifer; Thayer, Sarah P.

2013-01-01

Developmental genes are known to regulate cell proliferation, migration, and differentiation; thus, it comes as no surprise that the misregulation of developmental genes plays an important role in the biology of human cancers. One such pathway that has received an increasing amount of attention for its function in carcinogenesis is the Hedgehog (Hh) pathway. Initially the domain of developmental biologists, the Hh pathway and one of its ligands, Sonic Hedgehog (Shh), have been shown to play an important role in body planning and organ development, particularly in the foregut endoderm. Their importance in human disease became known to cancer biologists when germline mutations that resulted in the unregulated activity of the Hh pathway were found to cause basal cell carcinoma and medulloblastoma. Since then, misexpression of the Hh pathway has been shown to play an important role in many other cancers, including those of the pancreas. In many institutions, investigators are targeting misexpression of the Hh pathway in clinical trials, but there is still much fundamental knowledge to be gained about this pathway that can shape its clinical utility. This review will outline the evolution of our understanding of this pathway as it relates to the pancreas, as well as how the Hh pathway came to be a high-priority target for treatment. PMID:22770959

Establishment of mouse expanded potential stem cells

PubMed Central

Gao, Xuefei; Antunes, Liliana; Yu, Yong; Zhu, Zhexin; Wang, Juexuan; Kolodziejczyk, Aleksandra A.; Campos, Lia S.; Wang, Cui; Yang, Fengtang; Zhong, Zhen; Fu, Beiyuan; Eckersley-Maslin, Melanie A.; Woods, Michael; Tanaka, Yosuke; Chen, Xi; Wilkinson, Adam C.; Bussell, James; White, Jacqui; Ramirez-Solis, Ramiro; Reik, Wolf; Göttgens, Berthold; Teichmann, Sarah A.; Tam, Patrick P. L.; Nakauchi, Hiromitsu; Zou, Xiangang; Lu, Liming; Liu, Pentao

2018-01-01

Mouse embryonic stem cells derived from the epiblast1 contribute to the somatic lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive endoderm2 upon reintroduction to the blastocyst. Here we report that cultures of expanded potential stem cells can be established from individual eight-cell blastomeres, and by direct conversion of mouse embryonic stem cells and induced pluripotent stem cells. Remarkably, a single expanded potential stem cell can contribute both to the embryo proper and to the trophectoderm lineages in a chimaera assay. Bona fide trophoblast stem cell lines and extra-embryonic endoderm stem cells can be directly derived from expanded potential stem cells in vitro. Molecular analyses of the epigenome and single-cell transcriptome reveal enrichment for blastomere-specific signature and a dynamic DNA methylome in expanded potential stem cells. The generation of mouse expanded potential stem cells highlights the feasibility of establishing expanded potential stem cells for other mammalian species. PMID:29019987

Engineering the extracellular matrix for clinical applications: endoderm, mesoderm, and ectoderm.

PubMed

Williams, Miguel L; Bhatia, Sujata K

2014-03-01

Tissue engineering is rapidly progressing from a research-based discipline to clinical applications. Emerging technologies could be utilized to develop therapeutics for a wide range of diseases, but many are contingent on a cell scaffold that can produce proper tissue ultrastructure. The extracellular matrix, which a cell scaffold simulates, is not merely a foundation for tissue growth but a dynamic participant in cellular crosstalk and organ homeostasis. Cells change their growth rates, recruitment, and differentiation in response to the composition, modulus, and patterning of the substrate on which they reside. Cell scaffolds can regulate these factors through precision design, functionalization, and application. The ideal therapy would utilize highly specialized cell scaffolds to best mimic the tissue of interest. This paper discusses advantages and challenges of optimized cell scaffold design in the endoderm, mesoderm, and ectoderm for clinical applications in tracheal transplant, cardiac regeneration, and skin grafts, respectively. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nuclear movement regulated by non-Smad Nodal signaling via JNK is associated with Smad signaling during zebrafish endoderm specification.

PubMed

Hozumi, Shunya; Aoki, Shun; Kikuchi, Yutaka

2017-11-01

Asymmetric nuclear positioning is observed during animal development, but its regulation and significance in cell differentiation remain poorly understood. Using zebrafish blastulae, we provide evidence that nuclear movement towards the yolk syncytial layer, which comprises extraembryonic tissue, occurs in the first cells fated to differentiate into the endoderm. Nodal signaling is essential for nuclear movement, whereas nuclear envelope proteins are involved in movement through microtubule formation. Positioning of the microtubule-organizing center, which is proposed to be crucial for nuclear movement, is regulated by Nodal signaling and nuclear envelope proteins. The non-Smad JNK signaling pathway, which is downstream of Nodal signaling, regulates nuclear movement independently of the Smad pathway, and this nuclear movement is associated with Smad signal transduction toward the nucleus. Our study provides insight into the function of nuclear movement in Smad signaling toward the nucleus, and could be applied to the control of TGFβ signaling. © 2017. Published by The Company of Biologists Ltd.

The birth of embryonic pluripotency

PubMed Central

Boroviak, Thorsten; Nichols, Jennifer

2014-01-01

Formation of a eutherian mammal requires concurrent establishment of embryonic and extraembryonic lineages. The functions of the trophectoderm and primitive endoderm are to enable implantation in the maternal uterus, axis specification and delivery of nutrients. The pluripotent epiblast represents the founding cell population of the embryo proper, which is protected from ectopic and premature differentiation until it is required to respond to inductive cues to form the fetus. While positional information plays a major role in specifying the trophoblast lineage, segregation of primitive endoderm from epiblast depends upon gradual acquisition of transcriptional identity, directed but not initiated by fibroblast growth factor (FGF) signalling. Following early cleavage divisions and formation of the blastocyst, cells of the inner cell mass lose totipotency. Developing epiblast cells transiently attain the state of naive pluripotency and competence to self-renew in vitro as embryonic stem cells and in vivo by means of diapause. This property is lost after implantation as the epiblast epithelializes and becomes primed in preparation for gastrulation and subsequent organogenesis. PMID:25349450

Stage specific requirement of platelet-derived growth factor receptor-α in embryonic development.

PubMed

Qian, Chen; Wong, Carol Wing Yan; Wu, Zhongluan; He, Qiuming; Xia, Huimin; Tam, Paul Kwong Hang; Wong, Kenneth Kak Yuen; Lui, Vincent Chi Hang

2017-01-01

Platelet-derived growth factor receptor alpha (PDGFRα) is a cell-surface receptor tyrosine kinase for platelet-derived growth factors. Correct timing and level of Pdgfra expression is crucial for embryo development, and deletion of Pdgfra caused developmental defects of multiple endoderm and mesoderm derived structures, resulting in a complex phenotypes including orofacial cleft, spina bifida, rib deformities, and omphalocele in mice. However, it is not clear if deletion of Pdgfra at different embryonic stages differentially affects these structures. To address the temporal requirement of Pdgfra in embryonic development. We have deleted the Pdgfra in Pdgfra-expressing tissues at different embryonic stages in mice, examined and quantified the developmental anomalies. Current study showed that (i) conditional deletion of Pdgfra at different embryonic days (between E7.5 and E10.5) resulted in orofacial cleft, spina bifida, rib cage deformities, and omphalocele, and (ii) the day of Pdgfra deletion influenced the combinations, incidence and severities of these anomalies. Deletion of Pdgfra caused apoptosis of Pdgfra-expressing tissues, and developmental defects of their derivatives. Orofacial cleft, spina bifida and omphalocele are among the commonest skeletal and abdominal wall defects of newborns, but their genetic etiologies are largely unknown. The remarkable resemblance of our conditional Pdgfra knockout embryos to theses human congenital anomalies, suggesting that dysregulated PDGFRA expression could cause these anomalies in human. Future work should aim at defining (a) the regulatory elements for the expression of the human PDGFRA during embryonic development, and (b) if mutations / sequence variations of these regulatory elements cause these anomalies.

Hedgehog induction of murine vasculogenesis is mediated by Foxf1 and Bmp4.

PubMed

Astorga, Jeanette; Carlsson, Peter

2007-10-01

The first vasculature of the developing vertebrate embryo forms by assembly of endothelial cells into simple tubes from clusters of mesodermal angioblasts. Maturation of this vasculature involves remodeling, pruning and investment with mural cells. Hedgehog proteins are part of the instructive endodermal signal that triggers the assembly of the first primitive vessels in the mesoderm. We used a combination of genetic and in vitro culture methods to investigate the role of hedgehogs and their targets in murine extraembryonic vasculogenesis. We show that Bmps, in particular Bmp4, are crucial for vascular tube formation, that Bmp4 expression in extraembryonic tissues requires the forkhead transcription factor Foxf1 and that the role of hedgehog proteins in this process is to activate Foxf1 expression in the mesoderm. We show in the allantois that genetic disruption of hedgehog signaling (Smo(-/-)) has no effect on Foxf1 expression, and neither Bmp4 expression nor vasculogenesis are disturbed. By contrast, targeted inactivation of Foxf1 leads to loss of allantoic Bmp4 and vasculature. In vitro, the avascular Foxf1(-/-) phenotype can be rescued by exogenous Bmp4, and vasculogenesis in wild-type tissue can be blocked by the Bmp antagonist noggin. Hedgehogs are required for activation of Foxf1, Bmp4 expression and vasculogenesis in the yolk sac. However, vasculogenesis in Smo(-/-) yolk sacs can be rescued by exogenous Bmp4, consistent with the notion that the role of hedgehog signaling in primary vascular tube formation is as an activator of Bmp4, via Foxf1.

Transcriptional regulation of cranial sensory placode development

PubMed Central

Moody, Sally A.; LaMantia, Anthony-Samuel

2015-01-01

Cranial sensory placodes derive from discrete patches of the head ectoderm, and give rise to numerous sensory structures. During gastrulation, a specialized “neural border zone” forms around the neural plate in response to interactions between the neural and non-neural ectoderm and signals from adjacent mesodermal and/or endodermal tissues. This zone subsequently gives rise to two distinct precursor populations of the peripheral nervous system: the neural crest and the pre-placodal ectoderm (PPE). The PPE is a common field from which all cranial sensory placodes arise (adenohypophyseal, olfactory, lens, trigeminal, epibranchial, otic). Members of the Six family of transcription factors are major regulators of PPE specification, in partnership with co-factor proteins such as Eya. Six gene activity also maintains tissue boundaries between the PPE, neural crest and epidermis by repressing genes that specify the fates of those adjacent ectodermally-derived domains. As the embryo acquires anterior-posterior identity, the PPE becomes transcriptionally regionalized, and it subsequently subdivides into specific placodes with distinct developmental fates in response to signaling from adjacent tissues. Each placode is characterized by a unique transcriptional program that leads to the differentiation of highly specialized cells, such as neurosecretory cells, somatic sensory receptor cells, chemosensory neurons, peripheral glia and supporting cells. In this review, we summarize the transcriptional and signaling factors that regulate key steps of placode development, influence subsequent sensory neuron specification, and discuss what is known about mutations in some of the essential PPE genes that underlie human congenital syndromes. PMID:25662264

Generation of hepatocyte-like cells from human induced pluripotent stem (iPS) cells by co-culturing embryoid body cells with liver non-parenchymal cell line TWNT-1.

PubMed

Javed, M Shahid; Yaqoob, Naeem; Iwamuro, Masaya; Kobayashi, Naoya; Fujiwara, Toshiyoshi

2014-02-01

To generate a homogeneous population of patient-specific hepatocyte-like cells (HLCs) from human iPS cells those show the morphologic and phenotypic properties of primary human hepatocytes. An experimental study. Department of Surgery, Okayama University, Graduate School of Medicine, Japan, from April to December 2011. Human iPS cells were generated and maintained on ES qualified matrigel coated plates supplemented with mTeSR medium or alternatively on mitotically inactivated MEF feeder layer in DMEM/F12 medium containing 20% KOSR, 4ng/ml bFGF-2, 1 x 10-4 M 2-mercaptoethanol, 1 mmol/L NEAA, 2mM L-glutamine and 1% penicillin-streptomycin. iPS cells were differentiated to HLCs by sequential culture using a four step differentiation protocol: (I) Generation of embryoid bodies (EBs) in suspension culture; (II) Induction of definitive endoderm (DE) from 2 days old EBs by growth in human activin-A (100 ng/ml) and basic fibroblasts growth factor (bFGF2) (100 ng/ml) on matrigel coated plates; (III) Induction of hepatic progenitors by co-culture with non-parenchymal human hepatic stellate cell line (TWNT-1); and (IV) Maturation by culture in dexamethasone. Characterization was performed by RT-PCR and functional assays. The generated HLCs showed microscopically morphological phenotype of human hepatocytes, expressed liver-specific genes (ASGPR, Albumin, AFP, Sox17, Fox A2), secreted human liver-specific proteins such as albumin, synthesized urea and metabolized ammonia. Functional HLCs were generated from human iPS cells, which could be used for autologus hepatocyte transplantation for liver failure and as in vitro model for determining the metabolic and toxicological properties of drug compounds.

Neural markers reveal a one-segmented head in tardigrades (water bears).

PubMed

Mayer, Georg; Kauschke, Susann; Rüdiger, Jan; Stevenson, Paul A

2013-01-01

While recent neuroanatomical and gene expression studies have clarified the alignment of cephalic segments in arthropods and onychophorans, the identity of head segments in tardigrades remains controversial. In particular, it is unclear whether the tardigrade head and its enclosed brain comprises one, or several segments, or a non-segmental structure. To clarify this, we applied a variety of histochemical and immunocytochemical markers to specimens of the tardigrade Macrobiotus cf. harmsworthi and the onychophoran Euperipatoides rowelli. Our immunolabelling against serotonin, FMRFamide and α-tubulin reveals that the tardigrade brain is a dorsal, bilaterally symmetric structure that resembles the brain of onychophorans and arthropods rather than a circumoesophageal ring typical of cycloneuralians (nematodes and allies). A suboesophageal ganglion is clearly lacking. Our data further reveal a hitherto unknown, unpaired stomatogastric ganglion in Macrobiotus cf. harmsworthi, which innervates the ectodermal oesophagus and the endodermal midgut and is associated with the second leg-bearing segment. In contrast, the oesophagus of the onychophoran E. rowelli possesses no immunoreactive neurons, whereas scattered bipolar, serotonin-like immunoreactive cell bodies are found in the midgut wall. Furthermore, our results show that the onychophoran pharynx is innervated by a medullary loop nerve accompanied by monopolar, serotonin-like immunoreactive cell bodies. A comparison of the nervous system innervating the foregut and midgut structures in tardigrades and onychophorans to that of arthropods indicates that the stomatogastric ganglion is a potential synapomorphy of Tardigrada and Arthropoda. Its association with the second leg-bearing segment in tardigrades suggests that the second trunk ganglion is a homologue of the arthropod tritocerebrum, whereas the first ganglion corresponds to the deutocerebrum. We therefore conclude that the tardigrade brain consists of a single segmental region corresponding to the arthropod protocerebrum and, accordingly, that the tardigrade head is a non-composite, one-segmented structure.

Differentiation induction of mouse embryonic stem cells into sinus node-like cells by suramin

PubMed Central

Wiese, Cornelia; Nikolova, Teodora; Zahanich, Ihor; Sulzbacher, Sabine; Fuchs, Joerg; Yamanaka, Satoshi; Graf, Eva; Ravens, Ursula; Boheler, Kenneth R.; Wobus, Anna M.

2015-01-01

Background Embryonic stem (ES) cells differentiate into cardiac phenotypes representing early pacemaker-, atrial-, ventricular-, and sinus node-like cells, however, ES-derived specification into sinus nodal cells is not yet known. By using the naphthylamine derivative of urea, suramin, we were able to follow the process of cardiac specialization into sinus node-like cells. Methods Differentiating mouse ES cells were treated with suramin (500 μM) from day 5 to 7 of embryoid body formation, and cells were analysed for their differentiation potential via morphological analysis, flow cytometry, RT-PCR, immunohistochemistry and patch clamp analysis. Results Application of suramin resulted in an increased number of cardiac cells, but inhibition of neuronal, skeletal muscle and definitive endoderm differentiation. Immediately after suramin treatment, a decreased mesendoderm differentiation was found. Brachyury, FGF10, Wnt8 and Wnt3a transcript levels were significantly down-regulated, followed by a decrease in mesoderm- and cardiac progenitor-specific markers BMP2, GATA4/5, Wnt11, Isl1, Nkx2.5 and Tbx5 immediately after removal of the substance. With continued differentiation, a significant up-regulation of Brachyury, FGF10 and GATA5 transcript levels was observed, whereas Nkx2.5, Isl1, Tbx5, BMP2 and Wnt11 levels were normalized to control levels. At advanced differentiation stages, sinus node-specific HCN4, Tbx2 and Tbx3 transcript levels were significantly up-regulated. Immunofluorescence and patch-clamp analysis confirmed the increased number of sinus node-like cells, and electrophysiological analysis revealed a lower number of atrial- and ventricular-like cardiomyocytes following suramin treatment. Conclusion We conclude that the interference of suramin with the cardiac differentiation process modified mesoderm- and cardiac-specific gene expression resulting in enhanced formation of sinus node-like cells. PMID:19775764

Roles of CDX2 and EOMES in human induced trophoblast progenitor cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ying, E-mail: ying.chen@hc.msu.edu; Wang, Kai; Gong, Yun Guo

Highlights: ► CDX2 and EOMES play critical roles in human induced trophoblast progenitors (iTP). ► iTP cells directly transformed from fibroblasts. ► Differentiation of iTP cells into extravillous trophoblasts and syncytiotrophoblasts. -- Abstract: Abnormal trophoblast lineage proliferation and differentiation in early pregnancy have been associated with the pathogenesis of placenta diseases of pregnancy. However, there is still a gap in understanding the molecular mechanisms of early placental development due to the limited primary trophoblast cultures and fidelity of immortalized trophoblast lines. Trophoblasts stem (TS) cells, an in vitro model of trophectoderm that can differentiate into syncytiotrophoblasts and extravillous trophoblasts, canmore » be an attractive tool for early pregnancy research. TS cells are well established in mouse but not in humans due to insufficient knowledge of which trophoblast lineage-specific transcription factors are involved in human trophectoderm (TE) proliferation and differentiation. Here, we applied induced pluripotent stem cell technique to investigate the human trophoblast lineage-specific transcription factors. We established human induced trophoblast progenitor (iTP) cells by direct reprogramming the fibroblasts with a pool of mouse trophoblast lineage-specific transcription factors consisting of CDX2, EOMES, and ELF5. The human iTP cells exhibit epithelial morphology and can be maintained in vitro for more than 2 months. Gene expression profile of these cells was tightly clustered with human trophectoderm but not with human neuron progenitor cells, mesenchymal stem cells, or endoderm cells. These cells are capable of differentiating into cells with an invasive capacity, suggesting extravillous trophoblasts. They also form multi-nucleated cells which secrete human chorionic gonadotropin and estradiol, consistent with a syncytiotrophoblast phenotype. Our results provide the evidence that transcription factors CDX2 and EOMES may play critical roles in human iTP cell generation.« less

Directed Differentiation of Human Embryonic Stem Cells into Prostate Organoids In Vitro and its Perturbation by Low-Dose Bisphenol A Exposure.

PubMed

Calderon-Gierszal, Esther L; Prins, Gail S

2015-01-01

Studies using rodent and adult human prostate stem-progenitor cell models suggest that developmental exposure to the endocrine disruptor Bisphenol-A (BPA) can predispose to prostate carcinogenesis with aging. Unknown at present is whether the embryonic human prostate is equally susceptible to BPA during its natural developmental window. To address this unmet need, we herein report the construction of a pioneer in vitro human prostate developmental model to study the effects of BPA. The directed differentiation of human embryonic stem cells (hESC) into prostatic organoids in a spatial system was accomplished with precise temporal control of growth factors and steroids. Activin-induced definitive endoderm was driven to prostate specification by combined exposure to WNT10B and FGF10. Matrigel culture for 20-30 days in medium containing R-Spondin-1, Noggin, EGF, retinoic acid and testosterone was sufficient for mature prostate organoid development. Immunofluorescence and gene expression analysis confirmed that organoids exhibited cytodifferentiation and functional properties of the human prostate. Exposure to 1 nM or 10 nM BPA throughout differentiation culture disturbed early morphogenesis in a dose-dependent manner with 1 nM BPA increasing and 10 nM BPA reducing the number of branched structures formed. While differentiation of branched structures to mature organoids seemed largely unaffected by BPA exposure, the stem-like cell population increased, appearing as focal stem cell nests that have not properly entered lineage commitment rather than the rare isolated stem cells found in normally differentiated structures. These findings provide the first direct evidence that low-dose BPA exposure targets hESC and perturbs morphogenesis as the embryonic cells differentiate towards human prostate organoids, suggesting that the developing human prostate may be susceptible to disruption by in utero BPA exposures.

Dynamic positional fate map of the primary heart-forming region.

PubMed

Cui, Cheng; Cheuvront, Tracey J; Lansford, Rusty D; Moreno-Rodriguez, Ricardo A; Schultheiss, Thomas M; Rongish, Brenda J

2009-08-15

Here we show the temporal-spatial orchestration of early heart morphogenesis at cellular level resolution, in vivo, and reconcile conflicting positional fate mapping data regarding the primary heart-forming field(s). We determined the positional fates of precardiac cells using a precision electroporation approach in combination with wide-field time-lapse microscopy in the quail embryo, a warm-blooded vertebrate (HH Stages 4 through 10). Contrary to previous studies, the results demonstrate the existence of a "continuous" circle-shaped heart field that spans the midline, appearing at HH Stage 4, which then expands to form a wide arc of progenitors at HH Stages 5-7. Our time-resolved image data show that a subset of these cardiac progenitor cells do not overlap with the expression of common cardiogenic factors, Nkx-2.5 and Bmp-2, until HH Stage 10, when a tubular heart has formed, calling into question when cardiac fate is specified and by which key factors. Sub-groups and anatomical bands (cohorts) of heart precursor cells dramatically change their relative positions in a process largely driven by endodermal folding and other large-scale tissue deformations. Thus, our novel dynamic positional fate maps resolve the origin of cardiac progenitor cells in amniotes. The data also establish the concept that tissue motion contributes significantly to cellular position fate - i.e., much of the cellular displacement that occurs during assembly of a midline heart tube (HH Stage 9) is NOT due to "migration" (autonomous motility), a commonly held belief. Computational analysis of our time-resolved data lays the foundation for more precise analyses of how cardiac gene regulatory networks correlate with early heart tissue morphogenesis in birds and mammals.

Genome-Wide Direct Target Analysis Reveals a Role for SHORT-ROOT in Root Vascular Patterning through Cytokinin Homeostasis1[W][OA

PubMed Central

Cui, Hongchang; Hao, Yueling; Kovtun, Mikhail; Stolc, Viktor; Deng, Xing-Wang; Sakakibara, Hitoshi; Kojima, Mikiko

2011-01-01

SHORT-ROOT (SHR) is a key regulator of root growth and development in Arabidopsis (Arabidopsis thaliana). Made in the stele, the SHR protein moves into an adjacent cell layer, where it specifies endodermal cell fate; it is also essential for apical meristem maintenance, ground tissue patterning, vascular differentiation, and lateral root formation. Much has been learned about the mechanism by which SHR controls radial patterning, but how it regulates other aspects of root morphogenesis is still unclear. To dissect the SHR developmental pathway, we have determined the genome-wide locations of SHR direct targets using a chromatin immunoprecipitation followed by microarray analysis method. K-means clustering analysis not only identified additional quiescent center-specific SHR targets but also revealed a direct role for SHR in gene regulation in the pericycle and xylem. Using cell type-specific markers, we showed that in shr, the phloem and the phloem-associated pericycle expanded, whereas the xylem and xylem-associated pericycle diminished. Interestingly, we found that cytokinin level was elevated in shr and that exogenous cytokinin conferred a shr-like vascular patterning phenotype in wild-type root. By chromatin immunoprecipitation-polymerase chain reaction and reverse transcription-polymerase chain reaction assays, we showed that SHR regulates cytokinin homeostasis by directly controlling the transcription of cytokinin oxidase 3, a cytokinin catabolism enzyme preferentially expressed in the stele. Finally, overexpression of a cytokinin oxidase in shr alleviated its vascular patterning defect. On the basis of these results, we suggest that one mechanism by which SHR controls vascular patterning is the regulation of cytokinin homeostasis. PMID:21951467

Dental pulp of the third molar: a new source of pluripotent-like stem cells.

PubMed

Atari, Maher; Gil-Recio, Carlos; Fabregat, Marc; García-Fernández, Dani; Barajas, Miguel; Carrasco, Miguel A; Jung, Han-Sung; Alfaro, F Hernández; Casals, Nuria; Prosper, Felipe; Ferrés-Padró, Eduard; Giner, Luis

2012-07-15

Dental pulp is particularly interesting in regenerative medicine because of the accessibility and differentiation potential of the tissue. Dental pulp has an early developmental origin with multi-lineage differentiation potential as a result of its development during childhood and adolescence. However, no study has previously identified the presence of stem cell populations with embryonic-like phenotypes in human dental pulp from the third molar. In the present work, we describe a new population of dental pulp pluripotent-like stem cells (DPPSCs) that were isolated by culture in medium containing LIF, EGF and PDGF. These cells are SSEA4(+), OCT3/4(+), NANOG(+), SOX2(+), LIN28(+), CD13(+), CD105(+), CD34(-), CD45(-), CD90(+), CD29(+), CD73(+), STRO1(+) and CD146(-), and they show genetic stability in vitro based on genomic analysis with a newly described CGH technique. Interestingly, DPPSCs were able to form both embryoid-body-like structures (EBs) in vitro and teratoma-like structures that contained tissues derived from all three embryonic germ layers when injected in nude mice. We examined the capacity of DPPSCs to differentiate in vitro into tissues that have similar characteristics to mesoderm, endoderm and ectoderm layers in both 2D and 3D cultures. We performed a comparative RT-PCR analysis of GATA4, GATA6, MIXL1, NANOG, OCT3/4, SOX1 and SOX2 to determine the degree of similarity between DPPSCs, EBs and human induced pluripotent stem cells (hIPSCs). Our analysis revealed that DPPSCs, hIPSC and EBs have the same gene expression profile. Because DPPSCs can be derived from healthy human molars from patients of different sexes and ages, they represent an easily accessible source of stem cells, which opens a range of new possibilities for regenerative medicine.

Regulation of glycan structures in murine embryonic stem cells: combined transcript profiling of glycan-related genes and glycan structural analysis.

PubMed

Nairn, Alison V; Aoki, Kazuhiro; dela Rosa, Mitche; Porterfield, Mindy; Lim, Jae-Min; Kulik, Michael; Pierce, J Michael; Wells, Lance; Dalton, Stephen; Tiemeyer, Michael; Moremen, Kelley W

2012-11-02

The abundance and structural diversity of glycans on glycoproteins and glycolipids are highly regulated and play important roles during vertebrate development. Because of the challenges associated with studying glycan regulation in vertebrate embryos, we have chosen to study mouse embryonic stem (ES) cells as they differentiate into embryoid bodies (EBs) or into extraembryonic endodermal (ExE) cells as a model for cellular differentiation. We profiled N- and O-glycan structures isolated from these cell populations and examined transcripts encoding the corresponding enzymatic machinery for glycan biosynthesis in an effort to probe the mechanisms that drive the regulation of glycan diversity. During differentiation from mouse ES cells to either EBs or ExE cells, general trends were detected. The predominance of high mannose N-glycans in ES cells shifted to an equal abundance of complex and high mannose structures, increased sialylation, and increased α-Gal termination in the differentiated cell populations. Whereas core 1 O-glycan structures predominated in all three cell populations, increased sialylation and increased core diversity characterized the O-glycans of both differentiated cell types. Increased polysialylation was also found in both differentiated cell types. Differences between the two differentiated cell types included greater sialylation of N-glycans in EBs, whereas α-Gal-capped structures were more prevalent in ExE cells. Changes in glycan structures generally, but not uniformly, correlated with alterations in transcript abundance for the corresponding biosynthetic enzymes, suggesting that transcriptional regulation contributes significantly to the regulation of glycan expression. Knowledge of glycan structural diversity and transcript regulation should provide greater understanding of the roles of protein glycosylation in vertebrate development.

Cell Expansion During Directed Differentiation of Stem Cells Toward the Hepatic Lineage

PubMed Central

Raju, Ravali; Chau, David; Cho, Dong Seong; Park, Yonsil; Verfaillie, Catherine M.

2017-01-01

The differentiation of human pluripotent stem cells toward the hepatocyte lineage can potentially provide an unlimited source of functional hepatocytes for transplantation and extracorporeal bioartificial liver applications. It is anticipated that the quantities of cells needed for these applications will be in the order of 109–1010 cells, because of the size of the liver. An ideal differentiation protocol would be to enable directed differentiation to the hepatocyte lineage with simultaneous cell expansion. We introduced a cell expansion stage after the commitment of human embryonic stem cells to the endodermal lineage, to allow for at least an eightfold increase in cell number, with continuation of cell maturation toward the hepatocyte lineage. The progressive changes in the transcriptome were measured by expression array, and the expression dynamics of certain lineage markers was measured by mass cytometry during the differentiation and expansion process. The findings revealed that while cells were expanding they were also capable of progressing in their differentiation toward the hepatocyte lineage. In addition, our transcriptome, protein and functional studies, including albumin secretion, drug-induced CYP450 expression and urea production, all indicated that the hepatocyte-like cells obtained with or without cell expansion are very similar. This method of simultaneous cell expansion and hepatocyte differentiation should facilitate obtaining large quantities of cells for liver cell applications. PMID:27806669

Hemichordates and the Origin of Chordates

NASA Technical Reports Server (NTRS)

Gerhart, John; Kirschner, Marc; Lowe, Chris

2002-01-01

At the start of the period of the NASA grant three years ago, we had no information on the organization and development of the body axis of the hemichordate, Saccoglossus kowalevskii. Now we have substantial findings about the anteroposterior axis and dorsoventral axis, and based on this information, we have new insights about the origin of chordates from ancestral deuterostomes. We found ways to obtain and preserve large numbers of embryos and hatched juveniles. We can now collect about 40,000 embryos in the month of September, the time of S. kowalevskii spawning at Woods Hole. Excellent cDNA libraries were prepared from three developmental stages. From these libraries, we directly isolated about 30 gene ortholog sequences by screening and pcr techniques, all of these sequences of interest in the inquiry about the animal's organization and development. We also performed a mid-sized EST project (60,000 randomly picked clones, many of these arrayed). About half of these have been analyzed so far by blastx and are suitable for direct use of clones. We have obtained about 50 interesting sequences from this set. The rest still await analysis. Thus, at this time we have isolated orthologs of 80 genes that are known to be expressed in chordates in conserved domains and known to have interesting roles in chordate organization and development. The orthology of the S. kowalevskii sequences has been verified by neighbor joining and parsimony methods, with bootstrap estimates of validity. The S. kowalevskii sequences cluster with other deuterostome sequences, namely, other hemichordates, echinoderms, ascidians, amphioxus, or vertebrates, depending on what sequences are available in the database for comparison. We have used these sequences to do high quality in situ hybridization on S. kowalevskii embryos, and the results can be divided into three sections-those concerning the anteroposterior axis of S. kowalevskii in comparison to the same axis of chordates, those concerning the dorsoventral axis of S. kowalevskii in comparison to the same axis of chordates, and those concerning the signals and transcription factors found in the endoderm, of S. kowalevskii compared to the signals and transcription factors in the endo-mesodermal cells of Spemann's organizer of chordates.

The left-right asymmetry of liver lobation is generated by Pitx2c-mediated asymmetries in the hepatic diverticulum.

PubMed

Womble, Mandy; Amin, Nirav M; Nascone-Yoder, Nanette

2018-07-15

Internal organs exhibit left-right asymmetric sizes, shapes and anatomical positions, but how these different lateralities develop is poorly understood. Here we use the experimentally tractable Xenopus model to uncover the morphogenetic events that drive the left-right asymmetrical lobation of the liver. On the right side of the early hepatic diverticulum, endoderm cells become columnar and apically constricted, forming an expanded epithelial surface and, ultimately, an enlarged right liver lobe. In contrast, the cells on the left side become rounder, and rearrange into a compact, stratified architecture that produces a smaller left lobe. Side-specific gain- and loss-of-function studies reveal that asymmetric expression of the left-right determinant Pitx2c elicits distinct epithelial morphogenesis events in the left side of the diverticulum. Surprisingly, the cellular events induced by Pitx2c during liver development are opposite those induced in other digestive organs, suggesting divergent cellular mechanisms underlie the formation of different lateralities. Copyright © 2018 Elsevier Inc. All rights reserved.

Generation of Alveolar Epithelial Spheroids via Isolated Progenitor Cells from Human Pluripotent Stem Cells

PubMed Central

Gotoh, Shimpei; Ito, Isao; Nagasaki, Tadao; Yamamoto, Yuki; Konishi, Satoshi; Korogi, Yohei; Matsumoto, Hisako; Muro, Shigeo; Hirai, Toyohiro; Funato, Michinori; Mae, Shin-Ichi; Toyoda, Taro; Sato-Otsubo, Aiko; Ogawa, Seishi; Osafune, Kenji; Mishima, Michiaki

2014-01-01

Summary No methods for isolating induced alveolar epithelial progenitor cells (AEPCs) from human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) have been reported. Based on a study of the stepwise induction of alveolar epithelial cells (AECs), we identified carboxypeptidase M (CPM) as a surface marker of NKX2-1+ “ventralized” anterior foregut endoderm cells (VAFECs) in vitro and in fetal human and murine lungs. Using SFTPC-GFP reporter hPSCs and a 3D coculture system with fetal human lung fibroblasts, we showed that CPM+ cells isolated from VAFECs differentiate into AECs, demonstrating that CPM is a marker of AEPCs. Moreover, 3D coculture differentiation of CPM+ cells formed spheroids with lamellar-body-like structures and an increased expression of surfactant proteins compared with 2D differentiation. Methods to induce and isolate AEPCs using CPM and consequently generate alveolar epithelial spheroids would aid human pulmonary disease modeling and regenerative medicine. PMID:25241738

Arabidopsis Myosins XI1, XI2, and XIK Are Crucial for Gravity-Induced Bending of Inflorescence Stems

PubMed Central

Talts, Kristiina; Ilau, Birger; Ojangu, Eve-Ly; Tanner, Krista; Peremyslov, Valera V.; Dolja, Valerian V.; Truve, Erkki; Paves, Heiti

2016-01-01

Myosins and actin filaments in the actomyosin system act in concert in regulating cell structure and dynamics and are also assumed to contribute to plant gravitropic response. To investigate the role of the actomyosin system in the inflorescence stem gravitropism, we used single and multiple mutants affecting each of the 17 Arabidopsis myosins of class VIII and XI. We show that class XI but not class VIII myosins are required for stem gravitropism. Simultaneous loss of function of myosins XI1, XI2, and XIK leads to impaired gravitropic bending that is correlated with altered growth, stiffness, and insufficient sedimentation of gravity sensing amyloplasts in stem endodermal cells. The gravitropic defect of the corresponding triple mutant xi1 xi2 xik could be rescued by stable expression of the functional XIK:YFP in the mutant background, indicating a role of class XI myosins in this process. Altogether, our results emphasize the critical contributions of myosins XI in stem gravitropism of Arabidopsis. PMID:28066484

GEM-TREND: a web tool for gene expression data mining toward relevant network discovery

PubMed Central

Feng, Chunlai; Araki, Michihiro; Kunimoto, Ryo; Tamon, Akiko; Makiguchi, Hiroki; Niijima, Satoshi; Tsujimoto, Gozoh; Okuno, Yasushi

2009-01-01

Background DNA microarray technology provides us with a first step toward the goal of uncovering gene functions on a genomic scale. In recent years, vast amounts of gene expression data have been collected, much of which are available in public databases, such as the Gene Expression Omnibus (GEO). To date, most researchers have been manually retrieving data from databases through web browsers using accession numbers (IDs) or keywords, but gene-expression patterns are not considered when retrieving such data. The Connectivity Map was recently introduced to compare gene expression data by introducing gene-expression signatures (represented by a set of genes with up- or down-regulated labels according to their biological states) and is available as a web tool for detecting similar gene-expression signatures from a limited data set (approximately 7,000 expression profiles representing 1,309 compounds). In order to support researchers to utilize the public gene expression data more effectively, we developed a web tool for finding similar gene expression data and generating its co-expression networks from a publicly available database. Results GEM-TREND, a web tool for searching gene expression data, allows users to search data from GEO using gene-expression signatures or gene expression ratio data as a query and retrieve gene expression data by comparing gene-expression pattern between the query and GEO gene expression data. The comparison methods are based on the nonparametric, rank-based pattern matching approach of Lamb et al. (Science 2006) with the additional calculation of statistical significance. The web tool was tested using gene expression ratio data randomly extracted from the GEO and with in-house microarray data, respectively. The results validated the ability of GEM-TREND to retrieve gene expression entries biologically related to a query from GEO. For further analysis, a network visualization interface is also provided, whereby genes and gene annotations are dynamically linked to external data repositories. Conclusion GEM-TREND was developed to retrieve gene expression data by comparing query gene-expression pattern with those of GEO gene expression data. It could be a very useful resource for finding similar gene expression profiles and constructing its gene co-expression networks from a publicly available database. GEM-TREND was designed to be user-friendly and is expected to support knowledge discovery. GEM-TREND is freely available at . PMID:19728865

GEM-TREND: a web tool for gene expression data mining toward relevant network discovery.

PubMed

Feng, Chunlai; Araki, Michihiro; Kunimoto, Ryo; Tamon, Akiko; Makiguchi, Hiroki; Niijima, Satoshi; Tsujimoto, Gozoh; Okuno, Yasushi

2009-09-03

DNA microarray technology provides us with a first step toward the goal of uncovering gene functions on a genomic scale. In recent years, vast amounts of gene expression data have been collected, much of which are available in public databases, such as the Gene Expression Omnibus (GEO). To date, most researchers have been manually retrieving data from databases through web browsers using accession numbers (IDs) or keywords, but gene-expression patterns are not considered when retrieving such data. The Connectivity Map was recently introduced to compare gene expression data by introducing gene-expression signatures (represented by a set of genes with up- or down-regulated labels according to their biological states) and is available as a web tool for detecting similar gene-expression signatures from a limited data set (approximately 7,000 expression profiles representing 1,309 compounds). In order to support researchers to utilize the public gene expression data more effectively, we developed a web tool for finding similar gene expression data and generating its co-expression networks from a publicly available database. GEM-TREND, a web tool for searching gene expression data, allows users to search data from GEO using gene-expression signatures or gene expression ratio data as a query and retrieve gene expression data by comparing gene-expression pattern between the query and GEO gene expression data. The comparison methods are based on the nonparametric, rank-based pattern matching approach of Lamb et al. (Science 2006) with the additional calculation of statistical significance. The web tool was tested using gene expression ratio data randomly extracted from the GEO and with in-house microarray data, respectively. The results validated the ability of GEM-TREND to retrieve gene expression entries biologically related to a query from GEO. For further analysis, a network visualization interface is also provided, whereby genes and gene annotations are dynamically linked to external data repositories. GEM-TREND was developed to retrieve gene expression data by comparing query gene-expression pattern with those of GEO gene expression data. It could be a very useful resource for finding similar gene expression profiles and constructing its gene co-expression networks from a publicly available database. GEM-TREND was designed to be user-friendly and is expected to support knowledge discovery. GEM-TREND is freely available at http://cgs.pharm.kyoto-u.ac.jp/services/network.

Neighboring Genes Show Correlated Evolution in Gene Expression

PubMed Central

Ghanbarian, Avazeh T.; Hurst, Laurence D.

2015-01-01

When considering the evolution of a gene’s expression profile, we commonly assume that this is unaffected by its genomic neighborhood. This is, however, in contrast to what we know about the lack of autonomy between neighboring genes in gene expression profiles in extant taxa. Indeed, in all eukaryotic genomes genes of similar expression-profile tend to cluster, reflecting chromatin level dynamics. Does it follow that if a gene increases expression in a particular lineage then the genomic neighbors will also increase in their expression or is gene expression evolution autonomous? To address this here we consider evolution of human gene expression since the human-chimp common ancestor, allowing for both variation in estimation of current expression level and error in Bayesian estimation of the ancestral state. We find that in all tissues and both sexes, the change in gene expression of a focal gene on average predicts the change in gene expression of neighbors. The effect is highly pronounced in the immediate vicinity (<100 kb) but extends much further. Sex-specific expression change is also genomically clustered. As genes increasing their expression in humans tend to avoid nuclear lamina domains and be enriched for the gene activator 5-hydroxymethylcytosine, we conclude that, most probably owing to chromatin level control of gene expression, a change in gene expression of one gene likely affects the expression evolution of neighbors, what we term expression piggybacking, an analog of hitchhiking. PMID:25743543

Identification of Human HK Genes and Gene Expression Regulation Study in Cancer from Transcriptomics Data Analysis

PubMed Central

Zhang, Zhang; Liu, Jingxing; Wu, Jiayan; Yu, Jun

2013-01-01

The regulation of gene expression is essential for eukaryotes, as it drives the processes of cellular differentiation and morphogenesis, leading to the creation of different cell types in multicellular organisms. RNA-Sequencing (RNA-Seq) provides researchers with a powerful toolbox for characterization and quantification of transcriptome. Many different human tissue/cell transcriptome datasets coming from RNA-Seq technology are available on public data resource. The fundamental issue here is how to develop an effective analysis method to estimate expression pattern similarities between different tumor tissues and their corresponding normal tissues. We define the gene expression pattern from three directions: 1) expression breadth, which reflects gene expression on/off status, and mainly concerns ubiquitously expressed genes; 2) low/high or constant/variable expression genes, based on gene expression level and variation; and 3) the regulation of gene expression at the gene structure level. The cluster analysis indicates that gene expression pattern is higher related to physiological condition rather than tissue spatial distance. Two sets of human housekeeping (HK) genes are defined according to cell/tissue types, respectively. To characterize the gene expression pattern in gene expression level and variation, we firstly apply improved K-means algorithm and a gene expression variance model. We find that cancer-associated HK genes (a HK gene is specific in cancer group, while not in normal group) are expressed higher and more variable in cancer condition than in normal condition. Cancer-associated HK genes prefer to AT-rich genes, and they are enriched in cell cycle regulation related functions and constitute some cancer signatures. The expression of large genes is also avoided in cancer group. These studies will help us understand which cell type-specific patterns of gene expression differ among different cell types, and particularly for cancer. PMID:23382867

Congenital Heart Disease–Causing Gata4 Mutation Displays Functional Deficits In Vivo

PubMed Central

Misra, Chaitali; Sachan, Nita; McNally, Caryn Rothrock; Koenig, Sara N.; Nichols, Haley A.; Guggilam, Anuradha; Lucchesi, Pamela A.; Pu, William T.; Srivastava, Deepak; Garg, Vidu

2012-01-01

Defects of atrial and ventricular septation are the most frequent form of congenital heart disease, accounting for almost 50% of all cases. We previously reported that a heterozygous G296S missense mutation of GATA4 caused atrial and ventricular septal defects and pulmonary valve stenosis in humans. GATA4 encodes a cardiac transcription factor, and when deleted in mice it results in cardiac bifida and lethality by embryonic day (E)9.5. In vitro, the mutant GATA4 protein has a reduced DNA binding affinity and transcriptional activity and abolishes a physical interaction with TBX5, a transcription factor critical for normal heart formation. To characterize the mutation in vivo, we generated mice harboring the same mutation, Gata4 G295S. Mice homozygous for the Gata4 G295S mutant allele have normal ventral body patterning and heart looping, but have a thin ventricular myocardium, single ventricular chamber, and lethality by E11.5. While heterozygous Gata4 G295S mutant mice are viable, a subset of these mice have semilunar valve stenosis and small defects of the atrial septum. Gene expression studies of homozygous mutant mice suggest the G295S protein can sufficiently activate downstream targets of Gata4 in the endoderm but not in the developing heart. Cardiomyocyte proliferation deficits and decreased cardiac expression of CCND2, a member of the cyclin family and a direct target of Gata4, were found in embryos both homozygous and heterozygous for the Gata4 G295S allele. To further define functions of the Gata4 G295S mutation in vivo, compound mutant mice were generated in which specific cell lineages harbored both the Gata4 G295S mutant and Gata4 null alleles. Examination of these mice demonstrated that the Gata4 G295S protein has functional deficits in early myocardial development. In summary, the Gata4 G295S mutation functions as a hypomorph in vivo and leads to defects in cardiomyocyte proliferation during embryogenesis, which may contribute to the development of congenital heart defects in humans. PMID:22589735

An Alternative Culture Method to Maintain Genomic Hypomethylation of Mouse Embryonic Stem Cells Using MEK Inhibitor PD0325901 and Vitamin C.

PubMed

Li, Cuiping; Lai, Weiyi; Wang, Hailin

2018-06-01

Embryonic stem (ES) cells have the potential to differentiate into any of the three germ layers (endoderm, mesoderm, or ectoderm), and can generate many lineages for regenerative medicine. ES cell culture in vitro has long been the subject of widespread concerns. Classically, mouse ES cells are maintained in serum and leukemia inhibitory factor (LIF)-containing medium. However, under serum/LIF conditions, cells show heterogeneity in morphology and the expression profile of pluripotency-related genes, and are mostly in a metastable state. Moreover, cultured ES cells exhibit global hypermethylation, but naïve ES cells of the inner cell mass (ICM) and primordial germ cells (PGCs) are in a state of global hypomethylation. The hypomethylated state of ICM and PGCs is closely associated with their pluripotency. To improve mouse ES cell culture methods, we have recently developed a new method based on the selectively combined utilization of two small-molecule compounds to maintain the DNA hypomethylated and pluripotent state. Here, we present that the co-treatment of vitamin C (Vc) and PD0325901 can erase about 90% of 5-methylcytosine (5mC) at 5 days in mouse ES cells. The generated 5mC content is comparable to that in PGCs. The mechanistic investigation shows that PD0325901 up-regulates Prdm14 expression to suppress Dnmt3b (de novo DNA methyltransferase) and Dnmt3l (the cofactor of Dnmt3b), by reducing de novo 5mC synthesis. Vc facilitates the conversion of 5mC to 5-hydroxymethylcytosine (5hmC) catalyzed mainly by Tet1 and Tet2, indicating the involvement of both passive and active DNA demethylations. Moreover, under Vc/PD0325901 conditions, mouse ES cells show homogeneous morphology and pluripotent state. Collectively, we propose a novel and chemical-synergy culture method for achieving DNA hypomethylation and maintenance of pluripotency in mouse ES cells. The small-molecule chemical-dependent method overcomes the major shortcomings of serum culture, and holds promise to generate homogeneous ES cells for further clinical applications and researches.

Effect of Antibiotics against Mycoplasma sp. on Human Embryonic Stem Cells Undifferentiated Status, Pluripotency, Cell Viability and Growth

PubMed Central

Romorini, Leonardo; Riva, Diego Ariel; Blüguermann, Carolina; Videla Richardson, Guillermo Agustin; Scassa, Maria Elida; Sevlever, Gustavo Emilio; Miriuka, Santiago Gabriel

2013-01-01

Human embryonic stem cells (hESCs) are self-renewing pluripotent cells that can differentiate into specialized cells and hold great promise as models for human development and disease studies, cell-replacement therapies, drug discovery and in vitro cytotoxicity tests. The culture and differentiation of these cells are both complex and expensive, so it is essential to extreme aseptic conditions. hESCs are susceptible to Mycoplasma sp. infection, which is hard to detect and alters stem cell-associated properties. The purpose of this work was to evaluate the efficacy and cytotoxic effect of PlasmocinTM and ciprofloxacin (specific antibiotics used for Mycoplasma sp. eradication) on hESCs. Mycoplasma sp. infected HUES-5 884 (H5 884, stable hESCs H5-brachyury promoter-GFP line) cells were effectively cured with a 14 days PlasmocinTM 25 µg/ml treatment (curative treatment) while maintaining stemness characteristic features. Furthermore, cured H5 884 cells exhibit the same karyotype as the parental H5 line and expressed GFP, through up-regulation of brachyury promoter, at day 4 of differentiation onset. Moreover, H5 cells treated with ciprofloxacin 10 µg/ml for 14 days (mimic of curative treatment) and H5 and WA09 (H9) hESCs treated with PlasmocinTM 5 µg/ml (prophylactic treatment) for 5 passages retained hESCs features, as judged by the expression of stemness-related genes (TRA1-60, TRA1-81, SSEA-4, Oct-4, Nanog) at mRNA and protein levels. In addition, the presence of specific markers of the three germ layers (brachyury, Nkx2.5 and cTnT: mesoderm; AFP: endoderm; nestin and Pax-6: ectoderm) was verified in in vitro differentiated antibiotic-treated hESCs. In conclusion, we found that PlasmocinTM and ciprofloxacin do not affect hESCs stemness and pluripotency nor cell viability. However, curative treatments slightly diminished cell growth rate. This cytotoxic effect was reversible as cells regained normal growth rate upon antibiotic withdrawal. PMID:23936178

Regulation of TFIIIB during F9 cell differentiation.

PubMed

Athineos, Dimitris; Marshall, Lynne; White, Robert J

2010-03-12

Differentiation of F9 embryonal carcinoma (EC) cells into parietal endoderm (PE) provides a tractable model system for studying molecular events during early and inaccessible stages of murine development. PE formation is accompanied by extensive changes in gene expression both in vivo and in culture. One of the most dramatic is the ~10-fold decrease in transcriptional output by RNA polymerase (pol) III. This has been attributed to changes in activity of TFIIIB, a factor that is necessary and sufficient to recruit pol III to promoters. The goal of this study was to identify molecular changes that can account for the low activity of TFIIIB following F9 cell differentiation. Three essential subunits of TFIIIB decrease in abundance as F9 cells differentiate; these are Brf1 and Bdp1, which are pol III-specific, and TBP, which is also used by pols I and II. The decreased levels of Brf1 and Bdp1 proteins can be explained by reduced expression of the corresponding mRNAs. However, this is not the case for TBP, which is regulated post-transcriptionally. In proliferating cells, pol III transcription is stimulated by the proto-oncogene product c-Myc and the mitogen-activated protein kinase Erk, both of which bind to TFIIIB. However, c-Myc levels fall during differentiation and Erk becomes inactive through dephosphorylation. The diminished abundance of TFIIIB is therefore likely to be compounded by changes to these positive regulators that are required for its full activity. In addition, PE cells have elevated levels of the retinoblastoma protein RB, which is known to bind and repress TFIIIB. The low activity of TFIIIB in PE can be attributed to a combination of changes, any one of which could be sufficient to inhibit pol III transcription. Declining levels of essential TFIIIB subunits and of activators that are required for maximal TFIIIB activity are accompanied by an increase in a potent repressor of TFIIIB. These events provide fail-safe guarantees to ensure that pol III output is appropriate to the diminished metabolic requirements of terminally differentiated cells.

Neighboring Genes Show Correlated Evolution in Gene Expression.

PubMed

Ghanbarian, Avazeh T; Hurst, Laurence D

2015-07-01

When considering the evolution of a gene's expression profile, we commonly assume that this is unaffected by its genomic neighborhood. This is, however, in contrast to what we know about the lack of autonomy between neighboring genes in gene expression profiles in extant taxa. Indeed, in all eukaryotic genomes genes of similar expression-profile tend to cluster, reflecting chromatin level dynamics. Does it follow that if a gene increases expression in a particular lineage then the genomic neighbors will also increase in their expression or is gene expression evolution autonomous? To address this here we consider evolution of human gene expression since the human-chimp common ancestor, allowing for both variation in estimation of current expression level and error in Bayesian estimation of the ancestral state. We find that in all tissues and both sexes, the change in gene expression of a focal gene on average predicts the change in gene expression of neighbors. The effect is highly pronounced in the immediate vicinity (<100 kb) but extends much further. Sex-specific expression change is also genomically clustered. As genes increasing their expression in humans tend to avoid nuclear lamina domains and be enriched for the gene activator 5-hydroxymethylcytosine, we conclude that, most probably owing to chromatin level control of gene expression, a change in gene expression of one gene likely affects the expression evolution of neighbors, what we term expression piggybacking, an analog of hitchhiking. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Development and evolution of the vertebrate primary mouth

PubMed Central

Soukup, Vladimír; Horácek, Ivan; Cerny, Robert

2013-01-01

The vertebrate oral region represents a key interface between outer and inner environments, and its structural and functional design is among the limiting factors for survival of its owners. Both formation of the respective oral opening (primary mouth) and establishment of the food-processing apparatus (secondary mouth) require interplay between several embryonic tissues and complex embryonic rearrangements. Although many aspects of the secondary mouth formation, including development of the jaws, teeth or taste buds, are known in considerable detail, general knowledge about primary mouth formation is regrettably low. In this paper, primary mouth formation is reviewed from a comparative point of view in order to reveal its underestimated morphogenetic diversity among, and also within, particular vertebrate clades. In general, three main developmental modes were identified. The most common is characterized by primary mouth formation via a deeply invaginated ectodermal stomodeum and subsequent rupture of the bilaminar oral membrane. However, in salamander, lungfish and also in some frog species, the mouth develops alternatively via stomodeal collar formation contributed both by the ecto- and endoderm. In ray-finned fishes, on the other hand, the mouth forms via an ectoderm wedge and later horizontal detachment of the initially compressed oral epithelia with probably a mixed germ-layer derivation. A very intriguing situation can be seen in agnathan fishes: whereas lampreys develop their primary mouth in a manner similar to the most common gnathostome pattern, hagfishes seem to undergo a unique oropharyngeal morphogenesis when compared with other vertebrates. In discussing the early formative embryonic correlates of primary mouth formation likely to be responsible for evolutionary–developmental modifications of this area, we stress an essential role of four factors: first, positioning and amount of yolk tissue; closely related to, second, endoderm formation during gastrulation, which initiates the process and constrains possible evolutionary changes within this area; third, incipient structure of the stomodeal primordium at the anterior neural plate border, where the ectoderm component of the prospective primary mouth is formed; and fourth, the prime role of Pitx genes for establishment and later morphogenesis of oral region both in vertebrates and non-vertebrate chordates. PMID:22804777

Differential expression of GSK3β and pS9GSK3β in normal human tissues: can pS9GSK3β be an epithelial marker?

PubMed

Lee, Hojung; Ro, Jae Y

2015-01-01

Glycogen synthase kinase 3β (GSK3β) and phosphorylated GSK3β at Ser9 (pS9GSK3β) are crucial in cellular proliferation and metabolism. GSK3β and pS9GSK3β are deregulated in many diseases including tumors. Data on altered expression of GSK3β and pS9GSK3β are mainly limited to tumor tissues, thus the expression of GSK3β and pS9GSK3β in normal human tissue has been largely unknown. Thus, we examined the immunohistochemical localization of GSK3β and pS9GSK3β in human fetal and adult tissues, and also compared the expression pattern of GSK3β and pS9GSK3β with that of the CK7 and CK20. We found GSK3β expression in neurons of brain, myenteric plexus in gastrointestinal tract, squamous epithelium of skin, and mammary gland. The expression of pS9GSK3β was restricted to the epithelial cells of breast and pancreaticobiliary duct, distal nephron of kidney, gastrointestinal tract, fallopian tube, epididymis, secretory cell of prostatic gland, and umbrella cell of urinary tract. The staining pattern of pS9GSK3β and CK7 was overlapped in most organs except for gastrointestinal tract where CK7 was negative and CK20 was positive. Our results show that the expression of GSK3β may be associated with differentiation of ectodermal derived tissues and pS9GSK3β with that of epithelial cells of endodermal derived tissues in human. In addition, the expression of pS9GSK3β in the selective epithelial cells may indicate its association with secretory or barrier function of specific cells and may serve as another immunohistochemical marker for epithelial cells.

Development, Characterization, and Pluripotency Analysis of Buffalo (Bubalus bubalis) Embryonic Stem Cell Lines Derived from In Vitro–Fertilized, Hand-Guided Cloned, and Parthenogenetic Embryos

PubMed Central

Shah, Syed Mohmad; Saini, Neha; Ashraf, Syma; Zandi, Mohammad; Manik, Radhey Sham; Singla, Suresh Kumar; Palta, Prabhat

2015-01-01

Abstract We present the derivation, characterization, and pluripotency analysis of three buffalo embryonic stem cell (buESC) lines, from in vitro–fertilized, somatic cell nuclear–transferred, and parthenogenetic blastocysts. These cell lines were developed for later differentiation into germ lineage cells and elucidation of the signaling pathways involved. The cell lines were established from inner cell masses (ICMs) that were isolated manually from the in vitro–produced blastocysts. Most of the ICMs (45–55%) resulted in formation of primary colonies that were subcultured after 8–10 days, leading subsequently to the formation of three buESC lines, one from each blastocyst type. All the cell lines expressed stem cell markers, such as Alkaline Phosphatase, OCT4, NANOG, SSEA1, SSEA4, TRA-1-60, TRA-1-81, SOX2, REX1, CD-90, STAT3, and TELOMERASE. They differentiated into all three germ layers as determined by ectodermal, mesodermal, and endodermal RNA and protein markers. All of the cell lines showed equal expression of pluripotency markers as well as equivalent differentiation potential into all the three germ layers. The static suspension culture–derived embryoid bodies (EBs) showed greater expression of all the three germ layer markers as compared to hanging drop culture–derived EBs. When analyzed for germ layer marker expression, EBs derived from 15% fetal bovine serum (FBS)-based spontaneous differentiation medium showed greater differentiation across all the three germ layers as compared to those derived from Knock-Out Serum Replacement (KoSR)-based differentiation medium. PMID:26168169

Application of community phylogenetic approaches to understand gene expression: differential exploration of venom gene space in predatory marine gastropods.

PubMed

Chang, Dan; Duda, Thomas F

2014-06-05

Predatory marine gastropods of the genus Conus exhibit substantial variation in venom composition both within and among species. Apart from mechanisms associated with extensive turnover of gene families and rapid evolution of genes that encode venom components ('conotoxins'), the evolution of distinct conotoxin expression patterns is an additional source of variation that may drive interspecific differences in the utilization of species' 'venom gene space'. To determine the evolution of expression patterns of venom genes of Conus species, we evaluated the expression of A-superfamily conotoxin genes of a set of closely related Conus species by comparing recovered transcripts of A-superfamily genes that were previously identified from the genomes of these species. We modified community phylogenetics approaches to incorporate phylogenetic history and disparity of genes and their expression profiles to determine patterns of venom gene space utilization. Less than half of the A-superfamily gene repertoire of these species is expressed, and only a few orthologous genes are coexpressed among species. Species exhibit substantially distinct expression strategies, with some expressing sets of closely related loci ('under-dispersed' expression of available genes) while others express sets of more disparate genes ('over-dispersed' expression). In addition, expressed genes show higher dN/dS values than either unexpressed or ancestral genes; this implies that expression exposes genes to selection and facilitates rapid evolution of these genes. Few recent lineage-specific gene duplicates are expressed simultaneously, suggesting that expression divergence among redundant gene copies may be established shortly after gene duplication. Our study demonstrates that venom gene space is explored differentially by Conus species, a process that effectively permits the independent and rapid evolution of venoms in these species.

Reprogramming Enhancers to Drive Metastasis.

PubMed

Mostoslavsky, Raul; Bardeesy, Nabeel

2017-08-24

Acquired molecular changes can promote the spreading of primary tumor cells to distant tissues. In this issue of Cell, Roe et al. show that metastatic progression of pancreatic cancer involves large-scale enhancer reprogramming by Foxa1, which activates transcriptional program specifying early endodermal stem cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Sonic Hedgehog promotes the survival of neural crest cells by limiting apoptosis induced by the dependence receptor CDON during branchial arch development.

PubMed

Delloye-Bourgeois, Céline; Rama, Nicolas; Brito, José; Le Douarin, Nicole; Mehlen, Patrick

2014-09-26

Cell-adhesion molecule-related/Downregulated by Oncogenes (CDO or CDON) was identified as a receptor for the classic morphogen Sonic Hedgehog (SHH). It has been shown that, in cell culture, CDO also behaves as a SHH dependence receptor: CDO actively triggers apoptosis in absence of SHH via a proteolytic cleavage in CDO intracellular domain. We present evidence that CDO is also pro-apoptotic in the developing neural tube where SHH is known to act as a survival factor. SHH, produced by the ventral foregut endoderm, was shown to promote survival of facial neural crest cells (NCCs) that colonize the first branchial arch (BA1). We show here that the survival activity of SHH on neural crest cells is due to SHH-mediated inhibition of CDO pro-apoptotic activity. Silencing of CDO rescued NCCs from apoptosis observed upon SHH inhibition in the ventral foregut endoderm. Thus, the pair SHH/dependence receptor CDO may play an important role in neural crest cell survival during the formation of the first branchial arch. Copyright © 2014 Elsevier Inc. All rights reserved.

Generation of organized germ layers from a single mouse embryonic stem cell.

PubMed

Poh, Yeh-Chuin; Chen, Junwei; Hong, Ying; Yi, Haiying; Zhang, Shuang; Chen, Junjian; Wu, Douglas C; Wang, Lili; Jia, Qiong; Singh, Rishi; Yao, Wenting; Tan, Youhua; Tajik, Arash; Tanaka, Tetsuya S; Wang, Ning

2014-05-30

Mammalian inner cell mass cells undergo lineage-specific differentiation into germ layers of endoderm, mesoderm and ectoderm during gastrulation. It has been a long-standing challenge in developmental biology to replicate these organized germ layer patterns in culture. Here we present a method of generating organized germ layers from a single mouse embryonic stem cell cultured in a soft fibrin matrix. Spatial organization of germ layers is regulated by cortical tension of the colony, matrix dimensionality and softness, and cell-cell adhesion. Remarkably, anchorage of the embryoid colony from the 3D matrix to collagen-1-coated 2D substrates of ~1 kPa results in self-organization of all three germ layers: ectoderm on the outside layer, mesoderm in the middle and endoderm at the centre of the colony, reminiscent of generalized gastrulating chordate embryos. These results suggest that mechanical forces via cell-matrix and cell-cell interactions are crucial in spatial organization of germ layers during mammalian gastrulation. This new in vitro method could be used to gain insights on the mechanisms responsible for the regulation of germ layer formation.

MicroRNA-127 Promotes Mesendoderm Differentiation of Mouse Embryonic Stem Cells by Targeting Left-Right Determination Factor 2.

PubMed

Ma, Haixia; Lin, Yu; Zhao, Zhen-Ao; Lu, Xukun; Yu, Yang; Zhang, Xiaoxin; Wang, Qiang; Li, Lei

2016-06-03

Specification of the three germ layers is a fundamental process and is essential for the establishment of organ rudiments. Multiple genetic and epigenetic factors regulate this dynamic process; however, the function of specific microRNAs in germ layer differentiation remains unknown. In this study, we established that microRNA-127 (miR-127) is related to germ layer specification via microRNA array analysis of isolated three germ layers of E7.5 mouse embryos and was verified through differentiation of mouse embryonic stem cells. miR-127 is highly expressed in endoderm and primitive streak. Overexpression of miR-127 increases and inhibition of miR-127 decreases the expression of mesendoderm markers. We further show that miR-127 promotes mesendoderm differentiation through the nodal pathway, a determinative signaling pathway in early embryogenesis. Using luciferase reporter assay, left-right determination factor 2 (Lefty2), an antagonist of nodal, is identified to be a novel target of miR-127. Furthermore, the role of miR-127 in mesendoderm differentiation is attenuated by Lefty2 overexpression. Altogether, our results indicate that miR-127 accelerates mesendoderm differentiation of mouse embryonic stem cells through nodal signaling by targeting Lefty2. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The PCP genes Celsr1 and Vangl2 are required for normal lung branching morphogenesis

PubMed Central

Yates, Laura L.; Schnatwinkel, Carsten; Murdoch, Jennifer N.; Bogani, Debora; Formstone, Caroline J.; Townsend, Stuart; Greenfield, Andy; Niswander, Lee A.; Dean, Charlotte H.

2010-01-01

The lungs are generated by branching morphogenesis as a result of reciprocal signalling interactions between the epithelium and mesenchyme during development. Mutations that disrupt formation of either the correct number or shape of epithelial branches affect lung function. This, in turn, can lead to congenital abnormalities such as cystadenomatoid malformations, pulmonary hypertension or lung hypoplasia. Defects in lung architecture are also associated with adult lung disease, particularly in cases of idiopathic lung fibrosis. Identifying the signalling pathways which drive epithelial tube formation will likely shed light on both congenital and adult lung disease. Here we show that mutations in the planar cell polarity (PCP) genes Celsr1 and Vangl2 lead to disrupted lung development and defects in lung architecture. Lungs from Celsr1Crsh and Vangl2Lp mouse mutants are small and misshapen with fewer branches, and by late gestation exhibit thickened interstitial mesenchyme and defective saccular formation. We observe a recapitulation of these branching defects following inhibition of Rho kinase, an important downstream effector of the PCP signalling pathway. Moreover, epithelial integrity is disrupted, cytoskeletal remodelling perturbed and mutant endoderm does not branch normally in response to the chemoattractant FGF10. We further show that Celsr1 and Vangl2 proteins are present in restricted spatial domains within lung epithelium. Our data show that the PCP genes Celsr1 and Vangl2 are required for foetal lung development thereby revealing a novel signalling pathway critical for this process that will enhance our understanding of congenital and adult lung diseases and may in future lead to novel therapeutic strategies. PMID:20223754

FARO server: Meta-analysis of gene expression by matching gene expression signatures to a compendium of public gene expression data.

PubMed

Manijak, Mieszko P; Nielsen, Henrik B

2011-06-11

Although, systematic analysis of gene annotation is a powerful tool for interpreting gene expression data, it sometimes is blurred by incomplete gene annotation, missing expression response of key genes and secondary gene expression responses. These shortcomings may be partially circumvented by instead matching gene expression signatures to signatures of other experiments. To facilitate this we present the Functional Association Response by Overlap (FARO) server, that match input signatures to a compendium of 242 gene expression signatures, extracted from more than 1700 Arabidopsis microarray experiments. Hereby we present a publicly available tool for robust characterization of Arabidopsis gene expression experiments which can point to similar experimental factors in other experiments. The server is available at http://www.cbs.dtu.dk/services/faro/.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saito, Kayoko; Ikeya, Kiyoko; Kondo, Eri

Mosaicism is a mixed state, with two cell populations of different genetic origins caused by a cell mutation occurring after fertilization. In the present case, DNA analysis of lymphocytes led to a DMD diagnosis before death. Postmortem immunocytochemical and DNA analysis showed somatic mosaicism. At age 18 years, blood lymphocyte DNA analysis showed a DMD gene deletion, upstream from exon 7 to the 5{prime} end containing both muscle and brain promoters. As the patient`s mother and elder sister had no deletions, he was considered to have a new mutation. Immunocytochemical studies of postmortem tissues showed that dystrophin was absent frommore » the tongue, deltoid, intercostal, psoas and rectus femoris muscles, but there was a mix of dystrophin-positive and negative fibers in the rectus abdominis, cardiac, temporalis and sternocleidomastoid muscles. All diaphragm cells were dystrophin positive. Polymerase chain reaction (PCR) amplification from all tissues except the temporalis and sternocleidomastoid muscles, diaphragm and kidney, in which no deletion was found, showed the deletion from at least exon 6 to the 5{prime} end containing both muscle and brain promoters. In this case, a genomic deletion of the DMD gene contributed to the formation of tissues derived from both ectoderm and endoderm, and cells of mesodermal origin showed genotypic and phenotypic heterogeneity. Our results indicate a mutation of the present case may have occurred just before the period of germ layer formation. 34 refs., 7 figs.« less

Digital gene expression analysis of the zebra finch genome

PubMed Central

2010-01-01

Background In order to understand patterns of adaptation and molecular evolution it is important to quantify both variation in gene expression and nucleotide sequence divergence. Gene expression profiling in non-model organisms has recently been facilitated by the advent of massively parallel sequencing technology. Here we investigate tissue specific gene expression patterns in the zebra finch (Taeniopygia guttata) with special emphasis on the genes of the major histocompatibility complex (MHC). Results Almost 2 million 454-sequencing reads from cDNA of six different tissues were assembled and analysed. A total of 11,793 zebra finch transcripts were represented in this EST data, indicating a transcriptome coverage of about 65%. There was a positive correlation between the tissue specificity of gene expression and non-synonymous to synonymous nucleotide substitution ratio of genes, suggesting that genes with a specialised function are evolving at a higher rate (or with less constraint) than genes with a more general function. In line with this, there was also a negative correlation between overall expression levels and expression specificity of contigs. We found evidence for expression of 10 different genes related to the MHC. MHC genes showed relatively tissue specific expression levels and were in general primarily expressed in spleen. Several MHC genes, including MHC class I also showed expression in brain. Furthermore, for all genes with highest levels of expression in spleen there was an overrepresentation of several gene ontology terms related to immune function. Conclusions Our study highlights the usefulness of next-generation sequence data for quantifying gene expression in the genome as a whole as well as in specific candidate genes. Overall, the data show predicted patterns of gene expression profiles and molecular evolution in the zebra finch genome. Expression of MHC genes in particular, corresponds well with expression patterns in other vertebrates. PMID:20359325

A novel approach for human whole transcriptome analysis based on absolute gene expression of microarray data.

PubMed

Bikel, Shirley; Jacobo-Albavera, Leonor; Sánchez-Muñoz, Fausto; Cornejo-Granados, Fernanda; Canizales-Quinteros, Samuel; Soberón, Xavier; Sotelo-Mundo, Rogerio R; Del Río-Navarro, Blanca E; Mendoza-Vargas, Alfredo; Sánchez, Filiberto; Ochoa-Leyva, Adrian

2017-01-01

In spite of the emergence of RNA sequencing (RNA-seq), microarrays remain in widespread use for gene expression analysis in the clinic. There are over 767,000 RNA microarrays from human samples in public repositories, which are an invaluable resource for biomedical research and personalized medicine. The absolute gene expression analysis allows the transcriptome profiling of all expressed genes under a specific biological condition without the need of a reference sample. However, the background fluorescence represents a challenge to determine the absolute gene expression in microarrays. Given that the Y chromosome is absent in female subjects, we used it as a new approach for absolute gene expression analysis in which the fluorescence of the Y chromosome genes of female subjects was used as the background fluorescence for all the probes in the microarray. This fluorescence was used to establish an absolute gene expression threshold, allowing the differentiation between expressed and non-expressed genes in microarrays. We extracted the RNA from 16 children leukocyte samples (nine males and seven females, ages 6-10 years). An Affymetrix Gene Chip Human Gene 1.0 ST Array was carried out for each sample and the fluorescence of 124 genes of the Y chromosome was used to calculate the absolute gene expression threshold. After that, several expressed and non-expressed genes according to our absolute gene expression threshold were compared against the expression obtained using real-time quantitative polymerase chain reaction (RT-qPCR). From the 124 genes of the Y chromosome, three genes (DDX3Y, TXLNG2P and EIF1AY) that displayed significant differences between sexes were used to calculate the absolute gene expression threshold. Using this threshold, we selected 13 expressed and non-expressed genes and confirmed their expression level by RT-qPCR. Then, we selected the top 5% most expressed genes and found that several KEGG pathways were significantly enriched. Interestingly, these pathways were related to the typical functions of leukocytes cells, such as antigen processing and presentation and natural killer cell mediated cytotoxicity. We also applied this method to obtain the absolute gene expression threshold in already published microarray data of liver cells, where the top 5% expressed genes showed an enrichment of typical KEGG pathways for liver cells. Our results suggest that the three selected genes of the Y chromosome can be used to calculate an absolute gene expression threshold, allowing a transcriptome profiling of microarray data without the need of an additional reference experiment. Our approach based on the establishment of a threshold for absolute gene expression analysis will allow a new way to analyze thousands of microarrays from public databases. This allows the study of different human diseases without the need of having additional samples for relative expression experiments.

Differential gene expression analysis in glioblastoma cells and normal human brain cells based on GEO database.

PubMed

Wang, Anping; Zhang, Guibin

2017-11-01

The differentially expressed genes between glioblastoma (GBM) cells and normal human brain cells were investigated to performed pathway analysis and protein interaction network analysis for the differentially expressed genes. GSE12657 and GSE42656 gene chips, which contain gene expression profile of GBM were obtained from Gene Expression Omniub (GEO) database of National Center for Biotechnology Information (NCBI). The 'limma' data packet in 'R' software was used to analyze the differentially expressed genes in the two gene chips, and gene integration was performed using 'RobustRankAggreg' package. Finally, pheatmap software was used for heatmap analysis and Cytoscape, DAVID, STRING and KOBAS were used for protein-protein interaction, Gene Ontology (GO) and KEGG analyses. As results: i) 702 differentially expressed genes were identified in GSE12657, among those genes, 548 were significantly upregulated and 154 were significantly downregulated (p<0.01, fold-change >1), and 1,854 differentially expressed genes were identified in GSE42656, among the genes, 1,068 were significantly upregulated and 786 were significantly downregulated (p<0.01, fold-change >1). A total of 167 differentially expressed genes including 100 upregulated genes and 67 downregulated genes were identified after gene integration, and the genes showed significantly different expression levels in GBM compared with normal human brain cells (p<0.05). ii) Interactions between the protein products of 101 differentially expressed genes were identified using STRING and expression network was established. A key gene, called CALM3, was identified by Cytoscape software. iii) GO enrichment analysis showed that differentially expressed genes were mainly enriched in 'neurotransmitter:sodium symporter activity' and 'neurotransmitter transporter activity', which can affect the activity of neurotransmitter transportation. KEGG pathway analysis showed that the differentially expressed genes were mainly enriched in 'protein processing in endoplasmic reticulum', which can affect protein processing in endoplasmic reticulum. The results showed that: i) 167 differentially expressed genes were identified from two gene chips after integration; and ii) protein interaction network was established, and GO and KEGG pathway analyses were successfully performed to identify and annotate the key gene, which provide new insights for the studies on GBN at gene level.

Discovery and validation of a glioblastoma co-expressed gene module

PubMed Central

Dunwoodie, Leland J.; Poehlman, William L.; Ficklin, Stephen P.; Feltus, Frank Alexander

2018-01-01

Tumors exhibit complex patterns of aberrant gene expression. Using a knowledge-independent, noise-reducing gene co-expression network construction software called KINC, we created multiple RNAseq-based gene co-expression networks relevant to brain and glioblastoma biology. In this report, we describe the discovery and validation of a glioblastoma-specific gene module that contains 22 co-expressed genes. The genes are upregulated in glioblastoma relative to normal brain and lower grade glioma samples; they are also hypo-methylated in glioblastoma relative to lower grade glioma tumors. Among the proneural, neural, mesenchymal, and classical glioblastoma subtypes, these genes are most-highly expressed in the mesenchymal subtype. Furthermore, high expression of these genes is associated with decreased survival across each glioblastoma subtype. These genes are of interest to glioblastoma biology and our gene interaction discovery and validation workflow can be used to discover and validate co-expressed gene modules derived from any co-expression network. PMID:29541392

Discovery and validation of a glioblastoma co-expressed gene module.

PubMed

Dunwoodie, Leland J; Poehlman, William L; Ficklin, Stephen P; Feltus, Frank Alexander

2018-02-16

Tumors exhibit complex patterns of aberrant gene expression. Using a knowledge-independent, noise-reducing gene co-expression network construction software called KINC, we created multiple RNAseq-based gene co-expression networks relevant to brain and glioblastoma biology. In this report, we describe the discovery and validation of a glioblastoma-specific gene module that contains 22 co-expressed genes. The genes are upregulated in glioblastoma relative to normal brain and lower grade glioma samples; they are also hypo-methylated in glioblastoma relative to lower grade glioma tumors. Among the proneural, neural, mesenchymal, and classical glioblastoma subtypes, these genes are most-highly expressed in the mesenchymal subtype. Furthermore, high expression of these genes is associated with decreased survival across each glioblastoma subtype. These genes are of interest to glioblastoma biology and our gene interaction discovery and validation workflow can be used to discover and validate co-expressed gene modules derived from any co-expression network.

Extraembryonic origin of circulating endothelial cells.

PubMed

Pardanaud, Luc; Eichmann, Anne

2011-01-01

Circulating endothelial cells (CEC) are contained in the bone marrow and peripheral blood of adult humans and participate to the revascularization of ischemic tissues. These cells represent attractive targets for cell or gene therapy aimed at improving ischemic revascularization or inhibition of tumor angiogenesis. The embryonic origin of CEC has not been addressed previously. Here we use quail-chick chimeras to study CEC origin and participation to the developing vasculature. CEC are traced with different markers, in particular the QH1 antibody recognizing only quail endothelial cells. Using yolk-sac chimeras, where quail embryos are grafted onto chick yolk sacs and vice-versa, we show that CEC are generated in the yolk sac. These cells are mobilized during wound healing, demonstrating their participation to angiogenic repair processes. Furthermore, we found that the allantois is also able to give rise to CEC in situ. In contrast to the yolk sac and allantois, the embryo proper does not produce CEC. Our results show that CEC exclusively originate from extra-embryonic territories made with splanchnopleural mesoderm and endoderm, while definitive hematopoietic stem cells and endothelial cells are of intra-embryonic origin.

Gender-Specific Gene Expression in Post-Mortem Human Brain: Localization to Sex Chromosomes

PubMed Central

Vawter, Marquis P; Evans, Simon; Choudary, Prabhakara; Tomita, Hiroaki; Meador-Woodruff, Jim; Molnar, Margherita; Li, Jun; Lopez, Juan F; Myers, Rick; Cox, David; Watson, Stanley J; Akil, Huda; Jones, Edward G; Bunney, William E

2011-01-01

Gender differences in brain development and in the prevalence of neuropsychiatric disorders such as depression have been reported. Gender differences in human brain might be related to patterns of gene expression. Microarray technology is one useful method for investigation of gene expression in brain. We investigated gene expression, cell types, and regional expression patterns of differentially expressed sex chromosome genes in brain. We profiled gene expression in male and female dorsolateral prefrontal cortex, anterior cingulate cortex, and cerebellum using the Affymetrix oligonucleotide microarray platform. Differentially expressed genes between males and females on the Y chromosome (DBY, SMCY, UTY, RPS4Y, and USP9Y) and X chromosome (XIST) were confirmed using real-time PCR measurements. In situ hybridization confirmed the differential expression of gender-specific genes and neuronal expression of XIST, RPS4Y, SMCY, and UTY in three brain regions examined. The XIST gene, which silences gene expression on regions of the X chromosome, is expressed in a subset of neurons. Since a subset of neurons express gender-specific genes, neural subpopulations may exhibit a subtle sexual dimorphism at the level of differences in gene regulation and function. The distinctive pattern of neuronal expression of XIST, RPS4Y, SMCY, and UTY and other sex chromosome genes in neuronal subpopulations may possibly contribute to gender differences in prevalence noted for some neuropsychiatric disorders. Studies of the protein expression of these sex- chromosome-linked genes in brain tissue are required to address the functional consequences of the observed gene expression differences. PMID:14583743

Gene expression variability in human hepatic drug metabolizing enzymes and transporters.

PubMed

Yang, Lun; Price, Elvin T; Chang, Ching-Wei; Li, Yan; Huang, Ying; Guo, Li-Wu; Guo, Yongli; Kaput, Jim; Shi, Leming; Ning, Baitang

2013-01-01

Interindividual variability in the expression of drug-metabolizing enzymes and transporters (DMETs) in human liver may contribute to interindividual differences in drug efficacy and adverse reactions. Published studies that analyzed variability in the expression of DMET genes were limited by sample sizes and the number of genes profiled. We systematically analyzed the expression of 374 DMETs from a microarray data set consisting of gene expression profiles derived from 427 human liver samples. The standard deviation of interindividual expression for DMET genes was much higher than that for non-DMET genes. The 20 DMET genes with the largest variability in the expression provided examples of the interindividual variation. Gene expression data were also analyzed using network analysis methods, which delineates the similarities of biological functionalities and regulation mechanisms for these highly variable DMET genes. Expression variability of human hepatic DMET genes may affect drug-gene interactions and disease susceptibility, with concomitant clinical implications.

A novel approach for human whole transcriptome analysis based on absolute gene expression of microarray data

PubMed Central

Bikel, Shirley; Jacobo-Albavera, Leonor; Sánchez-Muñoz, Fausto; Cornejo-Granados, Fernanda; Canizales-Quinteros, Samuel; Soberón, Xavier; Sotelo-Mundo, Rogerio R.; del Río-Navarro, Blanca E.; Mendoza-Vargas, Alfredo; Sánchez, Filiberto

2017-01-01

Background In spite of the emergence of RNA sequencing (RNA-seq), microarrays remain in widespread use for gene expression analysis in the clinic. There are over 767,000 RNA microarrays from human samples in public repositories, which are an invaluable resource for biomedical research and personalized medicine. The absolute gene expression analysis allows the transcriptome profiling of all expressed genes under a specific biological condition without the need of a reference sample. However, the background fluorescence represents a challenge to determine the absolute gene expression in microarrays. Given that the Y chromosome is absent in female subjects, we used it as a new approach for absolute gene expression analysis in which the fluorescence of the Y chromosome genes of female subjects was used as the background fluorescence for all the probes in the microarray. This fluorescence was used to establish an absolute gene expression threshold, allowing the differentiation between expressed and non-expressed genes in microarrays. Methods We extracted the RNA from 16 children leukocyte samples (nine males and seven females, ages 6–10 years). An Affymetrix Gene Chip Human Gene 1.0 ST Array was carried out for each sample and the fluorescence of 124 genes of the Y chromosome was used to calculate the absolute gene expression threshold. After that, several expressed and non-expressed genes according to our absolute gene expression threshold were compared against the expression obtained using real-time quantitative polymerase chain reaction (RT-qPCR). Results From the 124 genes of the Y chromosome, three genes (DDX3Y, TXLNG2P and EIF1AY) that displayed significant differences between sexes were used to calculate the absolute gene expression threshold. Using this threshold, we selected 13 expressed and non-expressed genes and confirmed their expression level by RT-qPCR. Then, we selected the top 5% most expressed genes and found that several KEGG pathways were significantly enriched. Interestingly, these pathways were related to the typical functions of leukocytes cells, such as antigen processing and presentation and natural killer cell mediated cytotoxicity. We also applied this method to obtain the absolute gene expression threshold in already published microarray data of liver cells, where the top 5% expressed genes showed an enrichment of typical KEGG pathways for liver cells. Our results suggest that the three selected genes of the Y chromosome can be used to calculate an absolute gene expression threshold, allowing a transcriptome profiling of microarray data without the need of an additional reference experiment. Discussion Our approach based on the establishment of a threshold for absolute gene expression analysis will allow a new way to analyze thousands of microarrays from public databases. This allows the study of different human diseases without the need of having additional samples for relative expression experiments. PMID:29230367

The diffuse chemosensory system: exploring the iceberg toward the definition of functional roles.

PubMed

Sbarbati, Andrea; Bramanti, Placido; Benati, Donatella; Merigo, Flavia

2010-05-01

The diffuse chemosensory system (DCS) is an anatomical structure composed of solitary chemosensory cells (SCCs, also called solitary chemoreceptor cells), which have analogies with taste cells but are not aggregated in buds. The concept of DCS has been advanced, after the discovery that cells similar to gustatory elements are present in several organs. The elements forming the DCS share common morphological and biochemical characteristics with the taste cells located in taste buds of the oro-pharyngeal cavity but they are localized in internal organs. In particular, they may express molecules of the chemoreceptorial cascade (e.g. trans-membrane taste receptors, the G-protein alpha-gustducin, PLCbeta2, TRPM5). This article will focus on the mammalian DCS in apparatuses of endodermic origin (i.e. digestive and respiratory systems), which is composed of an enormous number of sensory elements and presents a multiplicity of morphological aspects. Recent research has provided an adequate description of these elements, but the functional role for the DCS in these apparatuses is unknown. The initial findings led to the definition of a DCS structured like an iceberg, with a mysterious "submerged" portion localized in the distal part of endodermic apparatuses. Recent work has focussed on the discovery of this submerged portion, which now appears less puzzling. However, the functional roles of the different cytotypes belonging to the DCS are not well known. Recent studies linked chemosensation of the intraluminal content to local control of absorptive and secretory (exocrine and endocrine) processes. Control of the microbial population and detection of irritants seem to be other possible functions of the DCS. In the light of these new findings, the DCS might be thought to be involved in a wide range of diseases of both the respiratory (e.g. asthma, chronic obstructive pulmonary disease, cystic fibrosis) and digestive apparatuses (absorptive or secretive diseases, dysmicrobism), as well as in systemic diseases (e.g. obesity, diabetes). A description of the functional roles of the DCS might be a first step toward the discovery of therapeutic approaches which target chemosensory mechanisms. Copyright 2010 Elsevier Ltd. All rights reserved.

Accelerated Evolution of Developmentally Biased Genes in the Tetraphenic Ant Cardiocondyla obscurior.

PubMed

Schrader, Lukas; Helanterä, Heikki; Oettler, Jan

2017-03-01

Plastic gene expression underlies phenotypic plasticity and plastically expressed genes evolve under different selection regimes compared with ubiquitously expressed genes. Social insects are well-suited models to elucidate the evolutionary dynamics of plastic genes for their genetically and environmentally induced discrete polymorphisms. Here, we study the evolution of plastically expressed genes in the ant Cardiocondyla obscurior-a species that produces two discrete male morphs in addition to the typical female polymorphism of workers and queens. Based on individual-level gene expression data from 28 early third instar larvae, we test whether the same evolutionary dynamics that pertain to plastically expressed genes in adults also pertain to genes with plastic expression during development. In order to quantify plasticity of gene expression over multiple contrasts, we develop a novel geometric measure. For genes expressed during development, we show that plasticity of expression is positively correlated with evolutionary rates. We furthermore find a strong correlation between expression plasticity and expression variation within morphs, suggesting a close link between active and passive plasticity of gene expression. Our results support the notion of relaxed selection and neutral processes as important drivers in the evolution of adaptive plasticity. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Analysis of multiplex gene expression maps obtained by voxelation.

PubMed

An, Li; Xie, Hongbo; Chin, Mark H; Obradovic, Zoran; Smith, Desmond J; Megalooikonomou, Vasileios

2009-04-29

Gene expression signatures in the mammalian brain hold the key to understanding neural development and neurological disease. Researchers have previously used voxelation in combination with microarrays for acquisition of genome-wide atlases of expression patterns in the mouse brain. On the other hand, some work has been performed on studying gene functions, without taking into account the location information of a gene's expression in a mouse brain. In this paper, we present an approach for identifying the relation between gene expression maps obtained by voxelation and gene functions. To analyze the dataset, we chose typical genes as queries and aimed at discovering similar gene groups. Gene similarity was determined by using the wavelet features extracted from the left and right hemispheres averaged gene expression maps, and by the Euclidean distance between each pair of feature vectors. We also performed a multiple clustering approach on the gene expression maps, combined with hierarchical clustering. Among each group of similar genes and clusters, the gene function similarity was measured by calculating the average gene function distances in the gene ontology structure. By applying our methodology to find similar genes to certain target genes we were able to improve our understanding of gene expression patterns and gene functions. By applying the clustering analysis method, we obtained significant clusters, which have both very similar gene expression maps and very similar gene functions respectively to their corresponding gene ontologies. The cellular component ontology resulted in prominent clusters expressed in cortex and corpus callosum. The molecular function ontology gave prominent clusters in cortex, corpus callosum and hypothalamus. The biological process ontology resulted in clusters in cortex, hypothalamus and choroid plexus. Clusters from all three ontologies combined were most prominently expressed in cortex and corpus callosum. The experimental results confirm the hypothesis that genes with similar gene expression maps might have similar gene functions. The voxelation data takes into account the location information of gene expression level in mouse brain, which is novel in related research. The proposed approach can potentially be used to predict gene functions and provide helpful suggestions to biologists.

Co-expression network analysis of duplicate genes in maize (Zea mays L.) reveals no subgenome bias.

PubMed

Li, Lin; Briskine, Roman; Schaefer, Robert; Schnable, Patrick S; Myers, Chad L; Flagel, Lex E; Springer, Nathan M; Muehlbauer, Gary J

2016-11-04

Gene duplication is prevalent in many species and can result in coding and regulatory divergence. Gene duplications can be classified as whole genome duplication (WGD), tandem and inserted (non-syntenic). In maize, WGD resulted in the subgenomes maize1 and maize2, of which maize1 is considered the dominant subgenome. However, the landscape of co-expression network divergence of duplicate genes in maize is still largely uncharacterized. To address the consequence of gene duplication on co-expression network divergence, we developed a gene co-expression network from RNA-seq data derived from 64 different tissues/stages of the maize reference inbred-B73. WGD, tandem and inserted gene duplications exhibited distinct regulatory divergence. Inserted duplicate genes were more likely to be singletons in the co-expression networks, while WGD duplicate genes were likely to be co-expressed with other genes. Tandem duplicate genes were enriched in the co-expression pattern where co-expressed genes were nearly identical for the duplicates in the network. Older gene duplications exhibit more extensive co-expression variation than younger duplications. Overall, non-syntenic genes primarily from inserted duplications show more co-expression divergence. Also, such enlarged co-expression divergence is significantly related to duplication age. Moreover, subgenome dominance was not observed in the co-expression networks - maize1 and maize2 exhibit similar levels of intra subgenome correlations. Intriguingly, the level of inter subgenome co-expression was similar to the level of intra subgenome correlations, and genes from specific subgenomes were not likely to be the enriched in co-expression network modules and the hub genes were not predominantly from any specific subgenomes in maize. Our work provides a comprehensive analysis of maize co-expression network divergence for three different types of gene duplications and identifies potential relationships between duplication types, duplication ages and co-expression consequences.

Tissue Non-Specific Genes and Pathways Associated with Diabetes: An Expression Meta-Analysis.

PubMed

Mei, Hao; Li, Lianna; Liu, Shijian; Jiang, Fan; Griswold, Michael; Mosley, Thomas

2017-01-21

We performed expression studies to identify tissue non-specific genes and pathways of diabetes by meta-analysis. We searched curated datasets of the Gene Expression Omnibus (GEO) database and identified 13 and five expression studies of diabetes and insulin responses at various tissues, respectively. We tested differential gene expression by empirical Bayes-based linear method and investigated gene set expression association by knowledge-based enrichment analysis. Meta-analysis by different methods was applied to identify tissue non-specific genes and gene sets. We also proposed pathway mapping analysis to infer functions of the identified gene sets, and correlation and independent analysis to evaluate expression association profile of genes and gene sets between studies and tissues. Our analysis showed that PGRMC1 and HADH genes were significant over diabetes studies, while IRS1 and MPST genes were significant over insulin response studies, and joint analysis showed that HADH and MPST genes were significant over all combined data sets. The pathway analysis identified six significant gene sets over all studies. The KEGG pathway mapping indicated that the significant gene sets are related to diabetes pathogenesis. The results also presented that 12.8% and 59.0% pairwise studies had significantly correlated expression association for genes and gene sets, respectively; moreover, 12.8% pairwise studies had independent expression association for genes, but no studies were observed significantly different for expression association of gene sets. Our analysis indicated that there are both tissue specific and non-specific genes and pathways associated with diabetes pathogenesis. Compared to the gene expression, pathway association tends to be tissue non-specific, and a common pathway influencing diabetes development is activated through different genes at different tissues.

The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.

PubMed

Hurst, Laurence D; Ghanbarian, Avazeh T; Forrest, Alistair R R; Huminiecki, Lukasz

2015-12-01

X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution.

The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome

PubMed Central

Hurst, Laurence D.; Ghanbarian, Avazeh T.; Forrest, Alistair R. R.; Huminiecki, Lukasz

2015-01-01

X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X’s gene content, gene expression, and evolution. PMID:26685068

Validating internal controls for quantitative plant gene expression studies.

PubMed

Brunner, Amy M; Yakovlev, Igor A; Strauss, Steven H

2004-08-18

Real-time reverse transcription PCR (RT-PCR) has greatly improved the ease and sensitivity of quantitative gene expression studies. However, accurate measurement of gene expression with this method relies on the choice of a valid reference for data normalization. Studies rarely verify that gene expression levels for reference genes are adequately consistent among the samples used, nor compare alternative genes to assess which are most reliable for the experimental conditions analyzed. Using real-time RT-PCR to study the expression of 10 poplar (genus Populus) housekeeping genes, we demonstrate a simple method for determining the degree of stability of gene expression over a set of experimental conditions. Based on a traditional method for analyzing the stability of varieties in plant breeding, it defines measures of gene expression stability from analysis of variance (ANOVA) and linear regression. We found that the potential internal control genes differed widely in their expression stability over the different tissues, developmental stages and environmental conditions studied. Our results support that quantitative comparisons of candidate reference genes are an important part of real-time RT-PCR studies that seek to precisely evaluate variation in gene expression. The method we demonstrated facilitates statistical and graphical evaluation of gene expression stability. Selection of the best reference gene for a given set of experimental conditions should enable detection of biologically significant changes in gene expression that are too small to be revealed by less precise methods, or when highly variable reference genes are unknowingly used in real-time RT-PCR experiments.

General statistics of stochastic process of gene expression in eukaryotic cells.

PubMed Central

Kuznetsov, V A; Knott, G D; Bonner, R F

2002-01-01

Thousands of genes are expressed at such very low levels (< or =1 copy per cell) that global gene expression analysis of rarer transcripts remains problematic. Ambiguity in identification of rarer transcripts creates considerable uncertainty in fundamental questions such as the total number of genes expressed in an organism and the biological significance of rarer transcripts. Knowing the distribution of the true number of genes expressed at each level and the corresponding gene expression level probability function (GELPF) could help resolve these uncertainties. We found that all observed large-scale gene expression data sets in yeast, mouse, and human cells follow a Pareto-like distribution model skewed by many low-abundance transcripts. A novel stochastic model of the gene expression process predicts the universality of the GELPF both across different cell types within a multicellular organism and across different organisms. This model allows us to predict the frequency distribution of all gene expression levels within a single cell and to estimate the number of expressed genes in a single cell and in a population of cells. A random "basal" transcription mechanism for protein-coding genes in all or almost all eukaryotic cell types is predicted. This fundamental mechanism might enhance the expression of rarely expressed genes and, thus, provide a basic level of phenotypic diversity, adaptability, and random monoallelic expression in cell populations. PMID:12136033

The changes of gene expression profiling between segmental vitiligo, generalized vitiligo and healthy individual.

PubMed

Wang, Ping; Li, Yong; Nie, Huiqiong; Zhang, Xiaoyan; Shao, Qiongyan; Hou, Xiuli; Xu, Wen; Hong, Weisong; Xu, Aie

2016-10-01

Vitiligo is a common acquired depigmentation skin disease characterized by loss or dysfunction of melanocytes within the skin lesion, but its pathologenesis is far from lucid. The gene expression profiling of segmental vitiligo (SV) and generalized vitiligo (GV) need further investigation. To better understanding the common and distinct factors, especially in the view of gene expression profile, which were involved in the diseases development and maintenance of segmental vitiligo (SV) and generalized vitiligo (GV). Peripheral bloods were collected from SV, GV and healthy individual (HI), followed by leukocytes separation and total RNA extraction. The high-throughput whole genome expression microarrays were used to assay the gene expression profiles between HI, SV and GV. Bioinformatics tools were employed to annotated the biological function of differently expressed genes. Quantitative PCR assay was used to validate the gene expression of array. Compared to HI, 239 over-expressed genes and 175 down-expressed genes detected in SV, 688 over-expressed genes and 560 down-expressed genes were found in GV, following the criteria of log2 (fold change)≥0.585 and P value<0.05. In these differently expressed genes, 60 over-expressed genes and 60 down-expressed genes had similar tendency in SV and GV. Compared to SV, 223 genes were up regulated and 129 genes were down regulated in GV. In the SV with HI as control, the differently expressed genes were mainly involved in the adaptive immune response, cytokine-cytokine receptor interaction, chemokine signaling, focal adhesion and sphingolipid metabolism. The differently expressed genes between GV and HI were mainly involved in the innate immune, autophagy, apoptosis, melanocyte biology, ubiquitin mediated proteolysis and tyrosine metabolism, which was different from SV. While the differently expressed genes between SV and GV were mainly involved in the metabolism pathway of purine, pyrimidine, glycolysis and sphingolipid. Above results suggested that they not only shared part bio-process and signal pathway, but more important, they utilized different biological mechanism in their pathogenesis and maintenance. Our results provide a comprehensive view on the gene expression profiling change between SV and GV especially in the side of leukocytes, and may facilitate the future study on their molecular mechanism and theraputic targets. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Identification of reference genes in human myelomonocytic cells for gene expression studies in altered gravity.

PubMed

Thiel, Cora S; Hauschild, Swantje; Tauber, Svantje; Paulsen, Katrin; Raig, Christiane; Raem, Arnold; Biskup, Josefine; Gutewort, Annett; Hürlimann, Eva; Unverdorben, Felix; Buttron, Isabell; Lauber, Beatrice; Philpot, Claudia; Lier, Hartwin; Engelmann, Frank; Layer, Liliana E; Ullrich, Oliver

2015-01-01

Gene expression studies are indispensable for investigation and elucidation of molecular mechanisms. For the process of normalization, reference genes ("housekeeping genes") are essential to verify gene expression analysis. Thus, it is assumed that these reference genes demonstrate similar expression levels over all experimental conditions. However, common recommendations about reference genes were established during 1 g conditions and therefore their applicability in studies with altered gravity has not been demonstrated yet. The microarray technology is frequently used to generate expression profiles under defined conditions and to determine the relative difference in expression levels between two or more different states. In our study, we searched for potential reference genes with stable expression during different gravitational conditions (microgravity, normogravity, and hypergravity) which are additionally not altered in different hardware systems. We were able to identify eight genes (ALB, B4GALT6, GAPDH, HMBS, YWHAZ, ABCA5, ABCA9, and ABCC1) which demonstrated no altered gene expression levels in all tested conditions and therefore represent good candidates for the standardization of gene expression studies in altered gravity.

Adaptation of Musca domestica L. Field Population to Laboratory Breeding Causes Transcriptional Alterations

PubMed Central

Højland, Dorte H.; Jensen, Karl-Martin Vagn; Kristensen, Michael

2014-01-01

Background The housefly, Musca domestica, has developed resistance to most insecticides applied for its control. Expression of genes coding for detoxification enzymes play a role in the response of the housefly when encountered by a xenobiotic. The highest level of constitutive gene expression of nine P450 genes was previously found in a newly-collected susceptible field population in comparison to three insecticide-resistant laboratory strains and a laboratory reference strain. Results We compared gene expression of five P450s by qPCR as well as global gene expression by RNAseq in the newly-acquired field population (845b) in generation F1, F13 and F29 to test how gene expression changes following laboratory adaption. Four (CYP6A1, CYP6A36, CYP6D3, CYP6G4) of five investigated P450 genes adapted to breeding by decreasing expression. CYP6D1 showed higher female expression in F29 than in F1. For males, about half of the genes accessed in the global gene expression were up-regulated in F13 and F29 in comparison with the F1 population. In females, 60% of the genes were up-regulated in F13 in comparison with F1, while 33% were up-regulated in F29. Forty potential P450 genes were identified. In most cases, P450 gene expression was decreased in F13 flies in comparison with F1. Gene expression then increased from F13 to F29 in males and decreased further in females. Conclusion The global gene expression changes massively during adaptation to laboratory breeding. In general, global expression decreased as a result of laboratory adaption in males, while female expression was not unidirectional. Expression of P450 genes was in general down-regulated as a result of laboratory adaption. Expression of hexamerin, coding for a storage protein was increased, while gene expression of genes coding for amylases decreased. This suggests a major impact of the surrounding environment on gene response to xenobiotics and genetic composition of housefly strains. PMID:24489682

An RNA-Seq based gene expression atlas of the common bean.

PubMed

O'Rourke, Jamie A; Iniguez, Luis P; Fu, Fengli; Bucciarelli, Bruna; Miller, Susan S; Jackson, Scott A; McClean, Philip E; Li, Jun; Dai, Xinbin; Zhao, Patrick X; Hernandez, Georgina; Vance, Carroll P

2014-10-06

Common bean (Phaseolus vulgaris) is grown throughout the world and comprises roughly 50% of the grain legumes consumed worldwide. Despite this, genetic resources for common beans have been lacking. Next generation sequencing, has facilitated our investigation of the gene expression profiles associated with biologically important traits in common bean. An increased understanding of gene expression in common bean will improve our understanding of gene expression patterns in other legume species. Combining recently developed genomic resources for Phaseolus vulgaris, including predicted gene calls, with RNA-Seq technology, we measured the gene expression patterns from 24 samples collected from seven tissues at developmentally important stages and from three nitrogen treatments. Gene expression patterns throughout the plant were analyzed to better understand changes due to nodulation, seed development, and nitrogen utilization. We have identified 11,010 genes differentially expressed with a fold change ≥ 2 and a P-value < 0.05 between different tissues at the same time point, 15,752 genes differentially expressed within a tissue due to changes in development, and 2,315 genes expressed only in a single tissue. These analyses identified 2,970 genes with expression patterns that appear to be directly dependent on the source of available nitrogen. Finally, we have assembled this data in a publicly available database, The Phaseolus vulgaris Gene Expression Atlas (Pv GEA), http://plantgrn.noble.org/PvGEA/ . Using the website, researchers can query gene expression profiles of their gene of interest, search for genes expressed in different tissues, or download the dataset in a tabular form. These data provide the basis for a gene expression atlas, which will facilitate functional genomic studies in common bean. Analysis of this dataset has identified genes important in regulating seed composition and has increased our understanding of nodulation and impact of the nitrogen source on assimilation and distribution throughout the plant.

Analysis of bHLH coding genes using gene co-expression network approach.

PubMed

Srivastava, Swati; Sanchita; Singh, Garima; Singh, Noopur; Srivastava, Gaurava; Sharma, Ashok

2016-07-01

Network analysis provides a powerful framework for the interpretation of data. It uses novel reference network-based metrices for module evolution. These could be used to identify module of highly connected genes showing variation in co-expression network. In this study, a co-expression network-based approach was used for analyzing the genes from microarray data. Our approach consists of a simple but robust rank-based network construction. The publicly available gene expression data of Solanum tuberosum under cold and heat stresses were considered to create and analyze a gene co-expression network. The analysis provide highly co-expressed module of bHLH coding genes based on correlation values. Our approach was to analyze the variation of genes expression, according to the time period of stress through co-expression network approach. As the result, the seed genes were identified showing multiple connections with other genes in the same cluster. Seed genes were found to be vary in different time periods of stress. These analyzed seed genes may be utilized further as marker genes for developing the stress tolerant plant species.

Quantitative imaging reveals real-time Pou5f3–Nanog complexes driving dorsoventral mesendoderm patterning in zebrafish

PubMed Central

Perez-Camps, Mireia; Tian, Jing; Chng, Serene C; Sem, Kai Pin; Sudhaharan, Thankiah; Teh, Cathleen; Wachsmuth, Malte; Korzh, Vladimir; Ahmed, Sohail; Reversade, Bruno

2016-01-01

Formation of the three embryonic germ layers is a fundamental developmental process that initiates differentiation. How the zebrafish pluripotency factor Pou5f3 (homologous to mammalian Oct4) drives lineage commitment is unclear. Here, we introduce fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy to assess the formation of Pou5f3 complexes with other transcription factors in real-time in gastrulating zebrafish embryos. We show, at single-cell resolution in vivo, that Pou5f3 complexes with Nanog to pattern mesendoderm differentiation at the blastula stage. Later, during gastrulation, Sox32 restricts Pou5f3–Nanog complexes to the ventrolateral mesendoderm by binding Pou5f3 or Nanog in prospective dorsal endoderm. In the ventrolateral endoderm, the Elabela / Aplnr pathway limits Sox32 levels, allowing the formation of Pou5f3–Nanog complexes and the activation of downstream BMP signaling. This quantitative model shows that a balance in the spatiotemporal distribution of Pou5f3–Nanog complexes, modulated by Sox32, regulates mesendoderm specification along the dorsoventral axis. DOI: http://dx.doi.org/10.7554/eLife.11475.001 PMID:27684073

Experimental study of the embryogenesis of gastrointestinal duplication and enteric cyst.

PubMed

Emura, Takaki; Hashizume, Kohei; Asashima, Makoto

2003-05-01

The theory of gastrointestinal duplication and enteric cyst embryogenesis was verified by examining the developmental process of this experimentally induced anomaly. In Cynopus pyrrhogaster (amphibian) embryos (stage 18), the dorsal midline structures (including the neural plate and notochord) were split regionally to induce partial separation of the notochord and gut anlage endoderm herniation between the split elements of the notochord. Following this procedure, the embryonic development was traced morphologically and histologically. Control embryos were cultured without the procedure. Following the incubation and breeding period, gastrointestinal duplication and enteric cysts were observed with vertebral anomaly, spina bifida, split cord malformation and subcutaneous manifestations in the mature animals. The combination of anomalies that was observed in these experimental animals is consistent with that found in "split notochord syndrome." No abnormal morphology or histology was observed in the control group. The embryogenetic theory of gastrointestinal duplication and enteric cysts was thus verified by simulating the partial separation of the notochord, which induced split notochord syndrome in laboratory animals. The results indicate that gastrointestinal duplication and enteric cysts may arise through a process of herniation of the gut anlage endoderm between split elements of the notochord.

The two nerve rings of the hypostomal nervous system of Hydra vulgaris-an immunohistochemical analysis.

PubMed

Hufnagel, L A; Kass-Simon, G

2016-11-01

In Hydra vulgaris, physiological and pharmacological evidence exists for a hypostomal circumferential neuro-effector pathway that initiates ectodermal pacemaker activity at tentacular-hypostomal loci coordinating body and tentacle contractions. Here, we describe an ectodermal nerve ring that runs below and between the tentacles, and an anti-GABA B receptor antibody-labeled ring coincident with it. The location of this ring is consistent with the physiology of the hypostomal pacemaker systems of hydra. We also describe a distally located, ectodermal ring of nerve fibers that is not associated with anti-GABA B receptor antibody labeling. The neurites and cell bodies of sensory cells contribute to both rings. The location of the distal ring and its sensory cell neurites suggests an involvement in the behavior of the mouth. Between the two rings is a network of anastomosing sensory and ganglion cell bodies and their neurites. Phase contrast, darkfield, and antibody-labeled images reveal that the mouth of hydra comprises five or six epithelial folds whose endoderm extensively labels with anti-GABA B receptor antibody, suggesting that endodermal metabotrobic GABA receptors are also involved in regulating mouth behavior.

Validating internal controls for quantitative plant gene expression studies

PubMed Central

Brunner, Amy M; Yakovlev, Igor A; Strauss, Steven H

2004-01-01

Background Real-time reverse transcription PCR (RT-PCR) has greatly improved the ease and sensitivity of quantitative gene expression studies. However, accurate measurement of gene expression with this method relies on the choice of a valid reference for data normalization. Studies rarely verify that gene expression levels for reference genes are adequately consistent among the samples used, nor compare alternative genes to assess which are most reliable for the experimental conditions analyzed. Results Using real-time RT-PCR to study the expression of 10 poplar (genus Populus) housekeeping genes, we demonstrate a simple method for determining the degree of stability of gene expression over a set of experimental conditions. Based on a traditional method for analyzing the stability of varieties in plant breeding, it defines measures of gene expression stability from analysis of variance (ANOVA) and linear regression. We found that the potential internal control genes differed widely in their expression stability over the different tissues, developmental stages and environmental conditions studied. Conclusion Our results support that quantitative comparisons of candidate reference genes are an important part of real-time RT-PCR studies that seek to precisely evaluate variation in gene expression. The method we demonstrated facilitates statistical and graphical evaluation of gene expression stability. Selection of the best reference gene for a given set of experimental conditions should enable detection of biologically significant changes in gene expression that are too small to be revealed by less precise methods, or when highly variable reference genes are unknowingly used in real-time RT-PCR experiments. PMID:15317655

Characterization of basal gene expression trends over a diurnal cycle in Xiphophorus maculatus skin, brain and liver.

PubMed

Lu, Yuan; Reyes, Jose; Walter, Sean; Gonzalez, Trevor; Medrano, Geraldo; Boswell, Mikki; Boswell, William; Savage, Markita; Walter, Ronald

2018-06-01

Evolutionarily conserved diurnal circadian mechanisms maintain oscillating patterns of gene expression based on the day-night cycle. Xiphophorus fish have been used to evaluate transcriptional responses after exposure to various light sources and it was determined that each source incites distinct genetic responses in skin tissue. However, basal expression levels of genes that show oscillating expression patterns in day-night cycle, may affect the outcomes of such experiments, since basal gene expression levels at each point in the circadian path may influence the profile of identified light responsive genes. Lack of knowledge regarding diurnal fluctuations in basal gene expression patterns may confound the understanding of genetic responses to external stimuli (e.g., light) since the dynamic nature of gene expression implies animals subjected to stimuli at different times may be at very different stages within the continuum of genetic homeostasis. We assessed basal gene expression changes over a 24-hour period in 200 select Xiphophorus gene targets known to transcriptionally respond to various types of light exposure. We identified 22 genes in skin, 36 genes in brain and 28 genes in liver that exhibit basal oscillation of expression patterns. These genes, including known circadian regulators, produced the expected expression patterns over a 24-hour cycle when compared to circadian regulatory genes identified in other species, especially human and other vertebrate animal models. Our results suggest the regulatory network governing diurnal oscillating gene expression is similar between Xiphophorus and other vertebrates for the three Xiphophorus organs tested. In addition, we were able to categorize light responsive gene sets in Xiphophorus that do, and do not, exhibit circadian based oscillating expression patterns. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of Reference Genes in Human Myelomonocytic Cells for Gene Expression Studies in Altered Gravity

PubMed Central

Thiel, Cora S.; Hauschild, Swantje; Tauber, Svantje; Paulsen, Katrin; Raig, Christiane; Raem, Arnold; Biskup, Josefine; Gutewort, Annett; Hürlimann, Eva; Philpot, Claudia; Lier, Hartwin; Engelmann, Frank; Layer, Liliana E.

2015-01-01

Gene expression studies are indispensable for investigation and elucidation of molecular mechanisms. For the process of normalization, reference genes (“housekeeping genes”) are essential to verify gene expression analysis. Thus, it is assumed that these reference genes demonstrate similar expression levels over all experimental conditions. However, common recommendations about reference genes were established during 1 g conditions and therefore their applicability in studies with altered gravity has not been demonstrated yet. The microarray technology is frequently used to generate expression profiles under defined conditions and to determine the relative difference in expression levels between two or more different states. In our study, we searched for potential reference genes with stable expression during different gravitational conditions (microgravity, normogravity, and hypergravity) which are additionally not altered in different hardware systems. We were able to identify eight genes (ALB, B4GALT6, GAPDH, HMBS, YWHAZ, ABCA5, ABCA9, and ABCC1) which demonstrated no altered gene expression levels in all tested conditions and therefore represent good candidates for the standardization of gene expression studies in altered gravity. PMID:25654098

Life-cycle and growth-phase-dependent regulation of the ubiquitin genes of Trypanosoma cruzi.

PubMed

Manning-Cela, Rebeca; Jaishankar, Sobha; Swindle, John

2006-07-01

Trypanosoma cruzi, the causative agent of Chagas disease, exhibits a complex life cycle that is accompanied by the stage-specific gene expression. At the molecular level, very little is known about gene regulation in trypanosomes. Complex gene organizations coupled with polycistronic transcription units make the analysis of regulated gene expression difficult in trypanosomes. The ubiquitin genes of T. cruzi are a good example of this complexity. They are organized as a single cluster containing five ubiquitin fusion (FUS) and five polyubiquitin (PUB) genes that are polycistronically transcribed but expressed differently in response to developmental and environmental changes. Gene replacements were used to study FUS and PUB gene expression at different stages of growth and at different points in the life cycle of T. cruzi. Based on the levels of reporter gene expression, it was determined that FUS1 expression was downregulated as the parasites approached stationary phase, whereas PUB12.5 polyubiquitin gene expression increased. Conversely, FUS1 expression increases when epimastigotes and amastigotes differentiate into trypomastigotes, whereas the expression of PUB12.5 decreases when epimastigotes differentiate into amastigotes and trypomastigotes. Although the level of CAT activity in logarithmic growing epimastigotes is six- to seven-fold higher when the gene was expressed from the FUS1 locus than when expressed from the PUB12.5 locus, the rate of transcription from the two loci was the same implying that post-transcriptional mechanisms play a dominant role in the regulation of gene expression.

Gene expression changes with age in skin, adipose tissue, blood and brain.

PubMed

Glass, Daniel; Viñuela, Ana; Davies, Matthew N; Ramasamy, Adaikalavan; Parts, Leopold; Knowles, David; Brown, Andrew A; Hedman, Asa K; Small, Kerrin S; Buil, Alfonso; Grundberg, Elin; Nica, Alexandra C; Di Meglio, Paola; Nestle, Frank O; Ryten, Mina; Durbin, Richard; McCarthy, Mark I; Deloukas, Panagiotis; Dermitzakis, Emmanouil T; Weale, Michael E; Bataille, Veronique; Spector, Tim D

2013-07-26

Previous studies have demonstrated that gene expression levels change with age. These changes are hypothesized to influence the aging rate of an individual. We analyzed gene expression changes with age in abdominal skin, subcutaneous adipose tissue and lymphoblastoid cell lines in 856 female twins in the age range of 39-85 years. Additionally, we investigated genotypic variants involved in genotype-by-age interactions to understand how the genomic regulation of gene expression alters with age. Using a linear mixed model, differential expression with age was identified in 1,672 genes in skin and 188 genes in adipose tissue. Only two genes expressed in lymphoblastoid cell lines showed significant changes with age. Genes significantly regulated by age were compared with expression profiles in 10 brain regions from 100 postmortem brains aged 16 to 83 years. We identified only one age-related gene common to the three tissues. There were 12 genes that showed differential expression with age in both skin and brain tissue and three common to adipose and brain tissues. Skin showed the most age-related gene expression changes of all the tissues investigated, with many of the genes being previously implicated in fatty acid metabolism, mitochondrial activity, cancer and splicing. A significant proportion of age-related changes in gene expression appear to be tissue-specific with only a few genes sharing an age effect in expression across tissues. More research is needed to improve our understanding of the genetic influences on aging and the relationship with age-related diseases.

Differential expression profiles and pathways of genes in sugarcane leaf at elongation stage in response to drought stress

PubMed Central

Li, Changning; Nong, Qian; Solanki, Manoj Kumar; Liang, Qiang; Xie, Jinlan; Liu, Xiaoyan; Li, Yijie; Wang, Weizan; Yang, Litao; Li, Yangrui

2016-01-01

Water stress causes considerable yield losses in sugarcane. To investigate differentially expressed genes under water stress, a pot experiment was performed with the sugarcane variety GT21 at three water-deficit levels (mild, moderate, and severe) during the elongation stage and gene expression was analyzed using microarray technology. Physiological parameters of sugarcane showed significant alterations in response to drought stress. Based on the expression profile of 15,593 sugarcane genes, 1,501 (9.6%) genes were differentially expressed under different water-level treatments; 821 genes were upregulated and 680 genes were downregulated. A gene similarity analysis showed that approximately 62.6% of the differentially expressed genes shared homology with functional proteins. In a Gene Ontology (GO) analysis, 901 differentially expressed genes were assigned to 36 GO categories. Moreover, 325 differentially expressed genes were classified into 101 pathway categories involved in various processes, such as the biosynthesis of secondary metabolites, ribosomes, carbon metabolism, etc. In addition, some unannotated genes were detected; these may provide a basis for studies of water-deficit tolerance. The reliability of the observed expression patterns was confirmed by RT-PCR. The results of this study may help identify useful genes for improving drought tolerance in sugarcane. PMID:27170459

GSEH: A Novel Approach to Select Prostate Cancer-Associated Genes Using Gene Expression Heterogeneity.

PubMed

Kim, Hyunjin; Choi, Sang-Min; Park, Sanghyun

2018-01-01

When a gene shows varying levels of expression among normal people but similar levels in disease patients or shows similar levels of expression among normal people but different levels in disease patients, we can assume that the gene is associated with the disease. By utilizing this gene expression heterogeneity, we can obtain additional information that abets discovery of disease-associated genes. In this study, we used collaborative filtering to calculate the degree of gene expression heterogeneity between classes and then scored the genes on the basis of the degree of gene expression heterogeneity to find "differentially predicted" genes. Through the proposed method, we discovered more prostate cancer-associated genes than 10 comparable methods. The genes prioritized by the proposed method are potentially significant to biological processes of a disease and can provide insight into them.

Circular RNA and gene expression profiles in gastric cancer based on microarray chip technology.

PubMed

Sui, Weiguo; Shi, Zhoufang; Xue, Wen; Ou, Minglin; Zhu, Ying; Chen, Jiejing; Lin, Hua; Liu, Fuhua; Dai, Yong

2017-03-01

The aim of the present study was to screen gastric cancer (GC) tissue and adjacent tissue for differences in mRNA and circular (circRNA) expression, to analyze the differences in circRNA and mRNA expression, and to investigate the circRNA expression in gastric carcinoma and its mechanism. circRNA and mRNA differential expression profiles generated using Agilent microarray technology were analyzed in the GC tissues and adjacent tissues. qRT-PCR was used to verify the differential expression of circRNAs and mRNAs according to the interactions between circRNAs and miRNAs as well as the possible existence of miRNA and mRNA interactions. We found that: i) the circRNA expression profile revealed 1,285 significant differences in circRNA expression, with circRNA expression downregulated in 594 samples and upregulated in 691 samples via interactions with miRNAs. The qRT-PCR validation experiments showed that hsa_circRNA_400071, hsa_circRNA_000543 and hsa_circRNA_001959 expression was consistent with the microarray analysis results. ii) 29,112 genes were found in the GC tissues and adjacent tissues, including 5,460 differentially expressed genes. Among them, 2,390 differentially expressed genes were upregulated and 3,070 genes were downregulated. Gene Ontology (GO) analysis of the differentially expressed genes revealed these genes involved in biological process classification, cellular component classification and molecular function classification. Pathway analysis of the differentially expressed genes identified 83 significantly enriched genes, including 28 upregulated genes and 55 downregulated genes. iii) 69 differentially expressed circRNAs were found that might adsorb specific miRNAs to regulate the expression of their target gene mRNAs. The conclusions are: i) differentially expressed circRNAs had corresponding miRNA binding sites. These circRNAs regulated the expression of target genes through interactions with miRNAs and might become new molecular biomarkers for GC in the future. ii) Differentially expressed genes may be involved in the occurrence of GC via a variety of mechanisms. iii) CD44, CXXC5, MYH9, MALAT1 and other genes may have important implications for the occurrence and development of GC through the regulation, interaction, and mutual influence of circRNA-miRNA-mRNA via different mechanisms.

A P-Norm Robust Feature Extraction Method for Identifying Differentially Expressed Genes

PubMed Central

Liu, Jian; Liu, Jin-Xing; Gao, Ying-Lian; Kong, Xiang-Zhen; Wang, Xue-Song; Wang, Dong

2015-01-01

In current molecular biology, it becomes more and more important to identify differentially expressed genes closely correlated with a key biological process from gene expression data. In this paper, based on the Schatten p-norm and Lp-norm, a novel p-norm robust feature extraction method is proposed to identify the differentially expressed genes. In our method, the Schatten p-norm is used as the regularization function to obtain a low-rank matrix and the Lp-norm is taken as the error function to improve the robustness to outliers in the gene expression data. The results on simulation data show that our method can obtain higher identification accuracies than the competitive methods. Numerous experiments on real gene expression data sets demonstrate that our method can identify more differentially expressed genes than the others. Moreover, we confirmed that the identified genes are closely correlated with the corresponding gene expression data. PMID:26201006

A P-Norm Robust Feature Extraction Method for Identifying Differentially Expressed Genes.

PubMed

Liu, Jian; Liu, Jin-Xing; Gao, Ying-Lian; Kong, Xiang-Zhen; Wang, Xue-Song; Wang, Dong

2015-01-01

In current molecular biology, it becomes more and more important to identify differentially expressed genes closely correlated with a key biological process from gene expression data. In this paper, based on the Schatten p-norm and Lp-norm, a novel p-norm robust feature extraction method is proposed to identify the differentially expressed genes. In our method, the Schatten p-norm is used as the regularization function to obtain a low-rank matrix and the Lp-norm is taken as the error function to improve the robustness to outliers in the gene expression data. The results on simulation data show that our method can obtain higher identification accuracies than the competitive methods. Numerous experiments on real gene expression data sets demonstrate that our method can identify more differentially expressed genes than the others. Moreover, we confirmed that the identified genes are closely correlated with the corresponding gene expression data.

Genetic and epigenetic architecture of sex-biased expression in the jewel wasps Nasonia vitripennis and giraulti

PubMed Central

Wang, Xu; Werren, John H.; Clark, Andrew G.

2015-01-01

There is extraordinary diversity in sexual dimorphism (SD) among animals, but little is known about its epigenetic basis. To study the epigenetic architecture of SD in a haplodiploid system, we performed RNA-seq and whole-genome bisulfite sequencing of adult females and males from two closely related parasitoid wasps, Nasonia vitripennis and Nasonia giraulti. More than 75% of expressed genes displayed significantly sex-biased expression. As a consequence, expression profiles are more similar between species within each sex than between sexes within each species. Furthermore, extremely male- and female-biased genes are enriched for totally different functional categories: male-biased genes for key enzymes in sex-pheromone synthesis and female-biased genes for genes involved in epigenetic regulation of gene expression. Remarkably, just 70 highly expressed, extremely male-biased genes account for 10% of all transcripts in adult males. Unlike expression profiles, DNA methylomes are highly similar between sexes within species, with no consistent sex differences in methylation found. Therefore, methylation changes cannot explain the extensive level of sex-biased gene expression observed. Female-biased genes have smaller sequence divergence between species, higher conservation to other hymenopterans, and a broader expression range across development. Overall, female-biased genes have been recruited from genes with more conserved and broadly expressing “house-keeping” functions, whereas male-biased genes are more recently evolved and are predominately testis specific. In summary, Nasonia accomplish a striking degree of sex-biased expression without sex chromosomes or epigenetic differences in methylation. We propose that methylation provides a general signal for constitutive gene expression, whereas other sex-specific signals cause sex-biased gene expression. PMID:26100871

Extent and character of circadian gene expression in Drosophila melanogaster: identification of twenty oscillating mRNAs in the fly head.

PubMed

Van Gelder, R N; Bae, H; Palazzolo, M J; Krasnow, M A

1995-12-01

Although mRNAs expressed with a circadian rhythm have been isolated from many species, the extent and character of circadianly regulated gene expression is unknown for any animal. In Drosophila melanogaster, only the period (per) gene, an essential component of the circadian pacemaker, is known to show rhythmic mRNA expression. Recent work suggests that the encoded Per protein controls its own transcription by an autoregulatory feedback loop. Per might also control the rhythmic expression of other genes to generate circadian behavior and physiology. The goals of this work were to evaluate the extent and character of circadian control of gene expression in Drosophila, and to identify genes dependent on per for circadian expression. A large collection of anonymous, independent cDNA clones was used to screen for transcripts that are rhythmically expressed in the fly head. 20 of the 261 clones tested detected mRNAs with a greater than two-fold daily change in abundance. Three mRNAs were maximally expressed in the morning, whereas 17 mRNAs were most abundant in the evening--when per mRNA is also maximally expressed (but when the flies are inactive). Further analysis of the three 'morning' cDNAs showed that each has a unique dependence on the presence of a light-dark cycle, on timed feeding, and on the function of the per gene for its oscillation. These dependencies were different from those determined for per and for a novel 'evening' gene. Sequence analysis indicated that all but one of the 20 cDNAs identified previously uncloned genes. Diurnal control of gene expression is a significant but limited phenomenon in the fly head, which involves many uncharacterized genes. Diurnal control is mediated by multiple endogenous and exogenous mechanisms, even at the level of individual genes. A subset of circadianly expressed genes are predominantly or exclusively dependent on per for their rhythmic expression. The per gene can therefore influence the expression of genes other than itself, but for many rhythmically expressed genes, per functions in conjunction with external inputs to control their daily expression patterns.