scholarly journals Zebrafish embryonic explants undergo genetically encoded self-assembly

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Alexandra Schauer ◽  
Diana Pinheiro ◽  
Robert Hauschild ◽  
Carl-Philipp Heisenberg
Keyword(s):  
Self Assembly ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Self Organization ◽  
Germ Layer ◽  
Maternal Factors ◽  
Head Mesoderm ◽  
Organization Capacity ◽  
Bona Fide ◽  
Extraembryonic Tissues

Embryonic stem cell cultures are thought to self-organize into embryoid bodies, able to undergo symmetry-breaking, germ layer specification and even morphogenesis. Yet, it is unclear how to reconcile this remarkable self-organization capacity with classical experiments demonstrating key roles for extrinsic biases by maternal factors and/or extraembryonic tissues in embryogenesis. Here, we show that zebrafish embryonic tissue explants, prepared prior to germ layer induction and lacking extraembryonic tissues, can specify all germ layers and form a seemingly complete mesendoderm anlage. Importantly, explant organization requires polarized inheritance of maternal factors from dorsal-marginal regions of the blastoderm. Moreover, induction of endoderm and head-mesoderm, which require peak Nodal-signaling levels, is highly variable in explants, reminiscent of embryos with reduced Nodal signals from the extraembryonic tissues. Together, these data suggest that zebrafish explants do not undergo bona fide self-organization, but rather display features of genetically encoded self-assembly, where intrinsic genetic programs control the emergence of order.

scholarly journals Optimization of the TeraTox assay for preclinical teratogenicity assessment

2021 ◽  
Author(s):  
Manuela Jaklin ◽  
Jitao David Zhang ◽  
Nicole Schaefer ◽  
Nicole Clemann ◽  
Paul Barrow ◽  
...  
Keyword(s):  
Gene Expression ◽  
Machine Learning ◽  
Stem Cell ◽  
Expression Profiles ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cell ◽  
Embryoid Bodies ◽  
Cell Renewal ◽  
Germ Layer

Teratogenicity poses severe threats to patient safety. Stem-cell-based in vitro systems are promising tools to predict human teratogenicity. However, current in vitro assays are limited because they either capture effects on a certain germ layer, or focus on a subset of predictive markers. Here we report the characterization and critical assessment of TeraTox, a newly developed multi-lineage differentiation assay using 3D human induced pluripotent stem cells. TeraTox probes stem-cell derived embryoid bodies with two endpoints, one quantifying cytotoxicity and the other inferring the teratogenicity potential with gene expression as a molecular phenotypic readout. To derive teratogenicity potentials from gene expression profiles, we applied both unsupervised machine-learning tools including factor analysis and supervised tools including classification and regression. To identify the best predictive model for the teratogenicity potential that is explainable, we systematically tested 64 machine-learning model architectures and identified the optimal model, which uses expression of 77 representative germ-layer genes, summarized by 10 latent germ-layer factors, as input for random-forest regression. We combined measured cytotoxicity and inferred teratogenicity potential to predict concentration-dependent teratogenicity profiles of 33 approved pharmaceuticals and 12 proprietary drug candidates with known in vivo data. Compared with the mouse embryonic stem cell test, which has been in routine use for more than a decade, the TeraTox assay shows higher sensitivity, particularly towards teratogens impairing ectodermal development or stem-cell renewal, and a more balanced prediction performance. We envision that further refinement and development of TeraTox has the potential to reduce and replace animal research in drug discovery and to improve preclinical assessment of teratogenicity.

scholarly journals Effects of Natural Progesterone and Synthetic Progestin on Germ Layer Gene Expression in a Human Embryoid Body Model

2020 ◽  
Vol 21 (3) ◽  
pp. 769 ◽  
Author(s):  
Yoon Young Kim ◽  
Hoon Kim ◽  
Chang Suk Suh ◽  
Hung-Ching Liu ◽  
Zev Rosenwaks ◽  
...  
Keyword(s):  
Gene Expression ◽  
Embryonic Development ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Germ Layer ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Endometrial Cells ◽  
Natural Progesterone

Natural progesterone and synthetic progestin are widely used for the treatment of threatened abortion or in in vitro fertilization (IVF) cycles. This in vitro study aimed to assess whether the treatment with natural progesterone or synthetic progestin influences the germ layer gene expression on the early human embryonic development using human embryonic stem cells (hESCs)-derived embryoid bodies (hEBs) as a surrogate of early stage human embryonic development. Human EBs derived from hESCs were cultured for nine days, and were treated with natural progesterone (P4) or synthetic progestin, medroxyprogesterone acetate (MPA) at 10–7 M for five days. To reverse the effects of treatment, mifepristone (RU486) as progesterone antagonist was added to the hEBs for four days starting one day after the initiation of treatment. Mouse blastocysts (mBLs) were cultured in vitro for 24 h, and P4 or MPA at 10−7 M was treated for an additional 24 h. The treated embryos were further transferred onto in vitro cultured endometrial cells to evaluate chorionic gonadotropin (CG) expression. To analyze the effects of P4 or MPA, the expression of differentiation genes representing the three germ layers was investigated, GATA-binding factor 4 (GATA4), α-fetoprotein (AFP), hepatocyte nuclear factor (HNF)-3β, hepatocyte nuclear factor (HNF)-4α (endoderm), Brachyury, cardiac actin (cACT) (mesoderm), and Nestin (ectoderm), using quantitative reverse transcription PCR (qRT-PCR) and immunostaining. Significantly lower expressions of HNF-3β, HNF-4α, Brachyury, and Nestin were observed in MPA-treated hEBs (all p < 0.05), which was negated by RU486 treatment. This inhibitory effect of MPA was also observed in mouse embryos. Conclusively, the effects of natural progesterone and synthetic progestin may differ in the germ layer gene expression in the hEB model, which suggests that caution is necessary in the use of progestogen.

scholarly journals Self-Organization Phenomena in Embryonic Stem Cell-Derived Embryoid Bodies: Axis Formation and Breaking of Symmetry during Cardiomyogenesis

2012 ◽  
Vol 195 (5) ◽  
pp. 377-391 ◽  
Author(s):  
Christiane Fuchs ◽  
Matthias Scheinast ◽  
Waltraud Pasteiner ◽  
Sabine Lagger ◽  
Manuela Hofner ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Self Organization ◽  
Axis Formation

scholarly journals Creating a human-induced pluripotent stem cell-based NKX2.5 reporter gene assay for developmental toxicity testing

2021 ◽  
Author(s):  
Karin Lauschke ◽  
Andreas Frederik Treschow ◽  
Mikkel Aabech Rasmussen ◽  
Nichlas Davidsen ◽  
Bjørn Holst ◽  
...  
Keyword(s):  
Stem Cell ◽  
Reporter Gene ◽  
Luminescence Intensity ◽  
Developmental Toxicity ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Luciferase Reporter ◽  
Reporter Cell ◽  
Gene Assay ◽  
Induced Pluripotent

AbstractTo test large numbers of chemicals for developmental toxicity, rapid in vitro tests with standardized readouts for automated data acquisition are needed. However, the most widely used assay, the embryonic stem cell test, relies on the counting of beating embryoid bodies by visual inspection, which is laborious and time consuming. We previously developed the PluriBeat assay based on differentiation of human induced pluripotent stem cells (hiPSC) that we demonstrated to be predictive for known teratogens at relevant concentrations using the readout of beating cardiomyocytes. Here, we report the development of a novel assay, which we term the PluriLum assay, where we have introduced a luciferase reporter gene into the locus ofNKX2.5of our hiPSC line. This enabled us to measure luminescence intensities instead of counting beating cardiomyocytes, which is less labor intensive. We established twoNKX2.5reporter cell lines and validated their pluripotency and genetic stability. Moreover, we confirmed that the genetically engineeredNKX2.5reporter cell line differentiated into cardiomyocytes with the same efficiency as the original wild-type line. We then exposed the cells to valproic acid (25–300 μM) and thalidomide (0.1–36 µM) and compared the PluriBeat readout of the cardiomyocytes with the luminescence intensity of the PluriLum assay. The results showed that thalidomide decreased luminescence intensity significantly with a higher potency and efficacy compared to the beating readout. With this, we have developed a novel hiPSC-based assay with a standardized readout that may have the potential for higher throughput screening for developmental toxicity.

scholarly journals Self-replication of a quantum artificial organism driven by single-photon pulses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Valente
Keyword(s):  
Self Assembly ◽  
Artificial Life ◽  
Single Photon ◽  
Self Organization ◽  
Physical Systems ◽  
Self Organized ◽  
Living Organisms ◽  
A Chain ◽  
Thermodynamic Mechanism ◽  
Self Replication

AbstractImitating the transition from inanimate to living matter is a longstanding challenge. Artificial life has achieved computer programs that self-replicate, mutate, compete and evolve, but lacks self-organized hardwares akin to the self-assembly of the first living cells. Nonequilibrium thermodynamics has achieved lifelike self-organization in diverse physical systems, but has not yet met the open-ended evolution of living organisms. Here, I look for the emergence of an artificial-life code in a nonequilibrium physical system undergoing self-organization. I devise a toy model where the onset of self-replication of a quantum artificial organism (a chain of lambda systems) is owing to single-photon pulses added to a zero-temperature environment. I find that spontaneous mutations during self-replication are unavoidable in this model, due to rare but finite absorption of off-resonant photons. I also show that the replication probability is proportional to the absorbed work from the photon, thereby fulfilling a dissipative adaptation (a thermodynamic mechanism underlying lifelike self-organization). These results hint at self-replication as the scenario where dissipative adaptation (pointing towards convergence) coexists with open-ended evolution (pointing towards divergence).

scholarly journals Ferro-self-assembly: magnetic and electrochemical adaptation of a multiresponsive zwitterionic metalloamphiphile showing a shape-hysteresis effect

2021 ◽  
Vol 12 (1) ◽  
pp. 270-281
Author(s):  
Stefan Bitter ◽  
Moritz Schlötter ◽  
Markus Schilling ◽  
Marina Krumova ◽  
Sebastian Polarz ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Real Time ◽  
Self Assembly ◽  
Hysteresis Effect ◽  
The Self ◽  
Self Organization ◽  
Stimuli Responsive ◽  
Optical Birefringence

The self-organization properties of a stimuli responsive amphiphile can be altered by subjecting the paramagnetic oxidized form to a magnetic field of 0.8 T and monitored in real time by coupling optical birefringence with dynamic light scattering.

Assessment of Differentiation Aspects by the Morphological Classification of Embryoid Bodies Derived from Human Embryonic Stem Cells

2011 ◽  
Vol 20 (11) ◽  
pp. 1925-1935 ◽  
Author(s):  
Jung Mo Kim ◽  
Sung-Hwan Moon ◽  
Sung Geum Lee ◽  
Youn Jeong Cho ◽  
Ki Sung Hong ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Morphological Classification

scholarly journals Regulation of Mineralocorticoid Receptor Expression during Neuronal Differentiation of Murine Embryonic Stem Cells

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2244-2254 ◽  
Author(s):  
Mathilde Munier ◽  
Geri Meduri ◽  
Say Viengchareun ◽  
Philippe Leclerc ◽  
Damien Le Menuet ◽  
...  
Keyword(s):  
Neuronal Differentiation ◽  
Mineralocorticoid Receptor ◽  
Fluorescent Protein ◽  
Morphological Changes ◽  
Critical Role ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Receptor Expression ◽  
Neuronal Markers ◽  
Mature Neurons

Mineralocorticoid receptor (MR) plays a critical role in brain function. However, the regulatory mechanisms controlling neuronal MR expression that constitutes a key element of the hormonal response are currently unknown. Two alternative P1 and P2 promoters drive human MR gene transcription. To examine promoter activities and their regulation during neuronal differentiation and in mature neurons, we generated stably transfected recombinant murine embryonic stem cell (ES) lines, namely P1-GFP and P2-GFP, in which each promoter drove the expression of the reporter gene green fluorescent protein (GFP). An optimized protocol, using embryoid bodies and retinoic acid, permitted us to obtain a reproducible neuronal differentiation as revealed by the decrease in phosphatase alkaline activity, the concomitant appearance of morphological changes (neurites), and the increase in the expression of neuronal markers (nestin, β-tubulin III, and microtubule-associated protein-2) as demonstrated by immunocytochemistry and quantitative PCR. Using these cell-based models, we showed that MR expression increased by 5-fold during neuronal differentiation, MR being preferentially if not exclusively expressed in mature neurons. Although the P2 promoter was always weaker than the P1 promoter during neuronal differentiation, their activities increased by 7- and 5-fold, respectively, and correlated with MR expression. Finally, although progesterone and dexamethasone were ineffective, aldosterone stimulated both P1 and P2 activity and MR expression, an effect that was abrogated by knockdown of MR by small interfering RNA. In conclusion, we provide evidence for a tight transcriptional control of MR expression during neuronal differentiation. Given the neuroprotective and antiapoptotic role proposed for MR, the neuronal differentiation of ES cell lines opens potential therapeutic perspectives in neurological and psychiatric diseases.

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