scholarly journals Gastruloids develop the three body axes in the absence of extraembryonic tissues and spatially localised signalling

2017 ◽  
Author(s):  
D.A. Turner ◽  
L. Alonso-Crisostomo ◽  
M. Girgin ◽  
P. Baillie-Johnson ◽  
C. R. Glodowski ◽  
...  
Keyword(s):  
Embryonic Stem ◽  
Model System ◽  
The Body ◽  
Genetic Studies ◽  
Animal Development ◽  
Embryonic Tissues ◽  
Bmp Signalling ◽  
Three Body ◽  
Extraembryonic Tissues

AbstractEstablishment of the three body axes is a critical step during animal development. In mammals, genetic studies have shown that a combination of precisely deployed signals from extraembryonic tissues position the anteroposterior axis (AP) within the embryo and lead to the emergence of the dorsoventral (DV) and left-right (LR) axes. We have used Gastruloids, embryonic organoids, as a model system to understand this process and find that they are able to develop AP, DV and LR axes as well as to undergo axial elongation in a manner that mirror embryos. The Gastruloids can be grown for 160 hours and form derivatives from ectoderm, mesoderm and endoderm. We focus on the AP axis and show that in the Gastruloids this axis is registered in the expression of T/Bra at one pole that corresponds to the tip of the elongation. We find that localisation of T/Bra expression depends on the combined activities of Wnt/β-Catenin and Nodal/Smad2,3 signalling, and that BMP signalling is dispensable for this process. Furthermore, AP axis specification occurs in the absence of both extraembryonic tissues and of localised sources of signalling. Our experiments show that Nodal, together with Wnt/β-Catenin signalling, is essential for the expression of T/Bra but that Wnt signalling has a separable activity in the elongation of the axis. The results lead us to suggest that, in the embryo, the role of the extraembryonic tissues might not be to induce the axes but to bias an intrinsic ability of the embryo to break its initial symmetry and organise its axes.One sentence summaryCulture of aggregates of defined number of Embryonic Stem cells leads to self-organised embryo-like structures which, in the absence of localised signalling from extra embryonic tissues and under the autonomous influence of Wnt and Nodal signalling, develop the three main axes of the body.

scholarly journals The Role of Insulation in Patterning Gene Expression

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 767 ◽  
Author(s):  
Özdemir ◽  
Gambetta
Keyword(s):  
Regulatory Element ◽  
Gene Promoter ◽  
Regulatory Elements ◽  
Spatial And Temporal Patterns ◽  
Genetic Studies ◽  
Animal Development ◽  
Binding Factor ◽  
Dna Elements ◽  
Biochemical Analyses

Development is orchestrated by regulatory elements that turn genes ON or OFF in precise spatial and temporal patterns. Many safety mechanisms prevent inappropriate action of a regulatory element on the wrong gene promoter. In flies and mammals, dedicated DNA elements (insulators) recruit protein factors (insulator binding proteins, or IBPs) to shield promoters from regulatory elements. In mammals, a single IBP called CCCTC-binding factor (CTCF) is known, whereas genetic and biochemical analyses in Drosophila have identified a larger repertoire of IBPs. How insulators function at the molecular level is not fully understood, but it is currently thought that they fold chromosomes into conformations that affect regulatory element-promoter communication. Here, we review the discovery of insulators and describe their properties. We discuss recent genetic studies in flies and mice to address the question: Is gene insulation important for animal development? Comparing and contrasting observations in these two species reveal that they have different requirements for insulation, but that insulation is a conserved and critical gene regulation strategy.

Generation of embryos directly from embryonic stem cells by tetraploid embryo complementation reveals a role for GATA factors in organogenesis

2005 ◽  
Vol 33 (6) ◽  
pp. 1534-1536 ◽  
Author(s):  
S.A. Duncan
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Es Cells ◽  
Embryonic Stem ◽  
Recipient Mouse ◽  
Gata Factors ◽  
Embryonic Tissues ◽  
Tetraploid Complementation ◽  
Traditional Procedure

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.

scholarly journals Interactions between Nodal and Wnt signalling Drive Robust Symmetry-Breaking and Axial Organisation in Gastruloids (Embryonic Organoids)

2016 ◽  
Author(s):  
D.A. Turner ◽  
C.R. Glodowski ◽  
L. Alonso-Crisostomo ◽  
P. Baillie-Johnson ◽  
P.C. Hayward ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Symmetry Breaking ◽  
Cell Fate ◽  
Embryonic Stem ◽  
Early Embryo ◽  
Model System ◽  
Wnt Signalling ◽  
Signalling Pathways ◽  
Cell Fate Decisions ◽  
Three Body

AbstractGeneration of asymmetry within the early embryo is a critical step in the establishment of the three body axes, providing a reference for the patterning of the organism. To study the establishment of asymmetry and the development of the anteroposterior axis (AP) in culture, we utilised our ‘Gastruloid’ model system. ‘Gastruloids’, highly reproducible embryonic organoids formed from aggregates of mouse embryonic stem cells, display symmetry-breaking, polarised gene expression and axial development, mirroring the processes on a time-scale similar to that of the mouse embyro. Using Gastruloids formed from mouse ESCs containing reporters for Wnt, FGF and Nodal signalling, we were able to quantitatively assess the contribution of these signalling pathways to the establishment of asymmetry through single time-point and live-cell fluorescence microscopy.During the first 24-48h of culture, interactions between the Wnt/β-Catenin and Nodal/TGF/β signalling pathways promote the initial symmetry-breaking event, manifested through polarised Brachyury (T/Bra) expression. Neither BMP nor FGF signalling is required for the establishment of asymmetry, however Wnt signalling is essential for the amplification and stability of the initial patterning event. Additionally, low, endogenous levels of FGF (24-48h) has a role in the amplification of the established pattern at later time-points.Our results confirm that Gastruloids behave like epiblast cells in the embryo, leading us to translate the processes and signalling involved in pattern formation of Gastruloids in culture to the development of the embryo, firmly establishing Gastruloids as a highly reproducible, robust model system for studying cell fate decisions and early pattern formation in culture.

scholarly journals Role of Metabolism in Bone Development and Homeostasis

2020 ◽  
Vol 21 (23) ◽  
pp. 8992
Author(s):  
Akiko Suzuki ◽  
Mina Minamide ◽  
Chihiro Iwaya ◽  
Kenichi Ogata ◽  
Junichi Iwata
Keyword(s):  
Metabolic Pathways ◽  
Metabolic Diseases ◽  
Bone Cells ◽  
Bone Development ◽  
Bone Matrix ◽  
The Body ◽  
Cellular Functions ◽  
Genetic Studies ◽  
Cellular Dysfunction

Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.

130 EXPRESSION AND LOCALIZATION OF µ OPIOID RECEPTOR IN PORCINE PRE-IMPLANTATION EMBRYOS

2010 ◽  
Vol 22 (1) ◽  
pp. 224 ◽  
Author(s):  
R. Minoia ◽  
T. Q. Dang-Nguyen ◽  
K. Matsukawa ◽  
M. Kaneda ◽  
M. E. Dell'Aquila ◽  
...  
Keyword(s):  
Stem Cell ◽  
G Protein ◽  
Cell Fate ◽  
Opioid Receptors ◽  
Embryonic Stem ◽  
Endogenous Opioids ◽  
The Body ◽  
Cell Fate Decisions ◽  
G Protein Coupled

Embryonic stem cells can become any tissue in the body, excluding a placenta. Growth factors, hormones, and neurotransmitters have been implicated in the regulation of their fate. Because various neural precursors express functional neurotransmitter receptors, as G-protein-coupled receptors, it is anticipated that they are involved in cell fate decisions. Moreover, a high level of endogenous opioids linked to G-protein-coupled receptor above all μ opioid receptors (MOR) has been shown to interfere with normal calcium metabolism and with the activity of the mitogen-activated protein kinase (MAPK). Thus it is very important to understand the possible influence of opioid activities in the regulation of stem cell fate. In this study we investigated the presence of MOR on porcine in vitro-produced embryos at one-cell, 4-cell, morula, and blastocyst stages by immunostaining. The COC were collected by aspiration, cultured in NCSU-37 medium supplemented with hormones for 20 to 22 h, and then in maturation medium without hormones for 24 h. After this time, COC were inseminated with frozen-thawed epididymal spermatozoa at the concentration of 10 × 5 sperm cells mL-1 for 3 h. After removal of cumulus cells, putative zygotes were cultured in IVC Pyr-Lac medium for the first 2 days and in IVC Glu medium until Day 6 (the day of IVF was defined as Day 0). Embryos at different stages were collected at 12, 36, 120, and 144 h post fertilization, and kept in 4% (v/v) paraformaldehyde until examination. All samples were washed and incubated for 30 min in PBS-1%BSA. Controls were incubated in PBS-1% BSA for 90 min, whereas embryos were incubated with a 1 : 2500 dilution of the primary rabbit antibody against the third extracellular loop of MOR. Prior to examination, all samples were washed in PBS and incubated with a FITC-conjugated anti rabbit IgG-secondary antibody diluted 1:200 in Evans Blue/PBS1x. Samples were visualized by laser scanning confocal microscope (Nikon). The immunofluorescence localize, by intense brilliant green, the presence of MOR on blastomers of all stage embryos examined, whereas the embryos of negative control did not show any fluorescent region or spotted coloring. Our results support specific implication of the opioid receptors in developmental process of porcine embryos. Their presence suggests a possible role of MOR in embryonic development. Thus it can be speculated that there is a role for MOR in controlling key events of the stem cell life. However, these primary results must be confirmed by the demonstration of protein expression (by Western blot) of MOR in the embryos and deeply studied to understand the exact functional role of MOR in them at this level. JSPS short-term scholarship.

Personality Traits and Body Weight Measures: Concurrent and Across–Time Associations

2013 ◽  
Vol 27 (4) ◽  
pp. 398-408 ◽  
Author(s):  
Galit Armon ◽  
Samuel Melamed ◽  
Arie Shirom ◽  
Itzhak Shapira ◽  
Shlomo Berliner
Keyword(s):  
Body Weight ◽  
Personality Traits ◽  
Factor Model ◽  
Five Factor Model ◽  
The Body ◽  
Cross Sectional ◽  
Longitudinal Regression ◽  
Three Body ◽  
Gender Specific

We tested the possibility that the five–factor model of personality is associated with three measures of body weight and with changes in their levels over time and that these associations are gender specific. The study was conducted at two points of time, Time 1 (2664 participants) and Time 2 (1492 participants), over approximately 4 years, controlling for gender, age, education, and having a chronic disease. Body weight was assessed by body mass index, waist circumference, waist–to–hip ratio, and the five–factor model by Saucier's Mini–Markers. Cross–sectional regression results indicated that conscientiousness was negatively associated with the three body weight measures, whereas neuroticism and extraversion were positively associated with the three body weight measures. The longitudinal regression results indicate that extraversion was associated with an increase in two of the body weight measures. Neuroticism was associated with increase in all three body weight measures and more strongly for women than for men. Openness was associated with a decrease in all three body weight measures for women, but this association was not significant for men. These findings help identify personality traits that lead to risk of weight gain and point to the modifying role of gender. Copyright © 2013 John Wiley & Sons, Ltd.

Growth factors in development: the role of TGF-β related polypeptide signalling molecules in embryogenesis

Development ◽  
1994 ◽  
Vol 1994 (Supplement) ◽  
pp. 53-60 ◽  
Author(s):  
Brigid L. M. Hogan ◽  
Manfred Blessing ◽  
Glenn E. Winnier ◽  
Noboru Suzuki ◽  
C. Michael Jones
Keyword(s):  
Growth Factors ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Related Gene ◽  
Genetic Studies ◽  
Signalling Molecules ◽  
Embryonic Tissues ◽  
Morphogenetic Protein ◽  
Large Families

Embryonic induction, the process by which signals from one cell population influence the fate of another, plays an essential role in the development of all organisms so far studied. In many cases, the signalling molecules belong to large families of highly conserved proteins, originally identified as mammalian growth factors. The largest known family is related to Transforming Growth Factor-β (TGF-β) and currently consists of at least 24 different members. Genetic studies in Drosophila on the TGF-β related gene, decapentaplegic (dpp), reveal the existence of conserved mechanisms regulating both the expression of the protein during development and the way in which it interacts with other signalling molecules to generate pattern within embryonic tissues. Comparative studies on another TGF-β related gene, known as Bone Morphogenetic Protein-4 (BMP-4), in Xenopus and mouse point to a conserved role in specifying posteroventral mesoderm during gastrulation. Analysis of other polypeptide signalling molecules during gastrulation suggests that their interaction in the generation of the overall body plan has also been conserved during vertebrate evolution.

scholarly journals Antisense Transcription through theXist Locus Mediates Tsix Function in Embryonic Stem Cells

2001 ◽  
Vol 21 (24) ◽  
pp. 8512-8520 ◽  
Author(s):  
Sandra Luikenhuis ◽  
Anton Wutz ◽  
Rudolf Jaenisch
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Antisense Transcription ◽  
Model System ◽  
X Inactivation ◽  
The Other ◽  
Es Cell ◽  
Targeted Deletion ◽  
First Time

ABSTRACT Expression of the Xist gene, a key player in mammalian X inactivation, has been proposed to be controlled by the antisense Tsix transcript. Targeted deletion of theTsix promoter encompassing the DPXas34 locus leads to nonrandom inactivation of the mutant X, but it remains unresolved whether this phenotype is caused by loss of Tsixtranscription or by deletion of a crucial DNA element. In this study we determined the role of Tsix transcription in random X inactivation by using mouse embryonic stem (ES) cells as a model system. Two approaches were chosen to modulate Tsixtranscription with minimal disturbance of genomic sequences. First,Tsix transcription was functionally inhibited by introducing a transcriptional stop signal into the transcribed region of Tsix. In the second approach, an inducible system forTsix expression was created. We found that the truncation of the Tsix transcript led to complete nonrandom inactivation of the targeted X chromosome. Induction of Tsix transcription during ES cell differentiation, on the other hand, caused the targeted chromosome always to be chosen as the active chromosome. These results for the first time establish a function for antisense transcription in the regulation of X inactivation.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

The Role of Computer Modeling in Electrocardiography

1990 ◽  
Vol 29 (04) ◽  
pp. 282-288 ◽  
Author(s):  
A. van Oosterom
Keyword(s):  
Electrical Activity ◽  
Computer Modeling ◽  
Body Surface ◽  
Electrical Current ◽  
The Body ◽  
Volume Conductor ◽  
Current Generator ◽  
Cardiac Electrical Activity ◽  
Source Models

AbstractThis paper introduces some levels at which the computer has been incorporated in the research into the basis of electrocardiography. The emphasis lies on the modeling of the heart as an electrical current generator and of the properties of the body as a volume conductor, both playing a major role in the shaping of the electrocardiographic waveforms recorded at the body surface. It is claimed that the Forward-Problem of electrocardiography is no longer a problem. Several source models of cardiac electrical activity are considered, one of which can be directly interpreted in terms of the underlying electrophysiology (the depolarization sequence of the ventricles). The importance of using tailored rather than textbook geometry in inverse procedures is stressed.

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