-
Current Topics in Developmental Biology 2024External bilateral symmetry is a prevalent feature in vertebrates, which emerges during early embryonic development. To begin with, vertebrate embryos are largely... (Review)
Review
External bilateral symmetry is a prevalent feature in vertebrates, which emerges during early embryonic development. To begin with, vertebrate embryos are largely radially symmetric before transitioning to bilaterally symmetry, after which, morphogenesis of various bilateral tissues (e.g somites, otic vesicle, limb bud), and structures (e.g palate, jaw) ensue. While a significant amount of work has probed the mechanisms behind symmetry breaking in the left-right axis leading to asymmetric positioning of internal organs, little is known about how bilateral tissues emerge at the same time with the same shape and size and at the same position on the two sides of the embryo. By discussing emergence of symmetry in many bilateral tissues and structures across vertebrate model systems, we highlight that understanding symmetry establishment is largely an open field, which will provide deep insights into fundamental problems in developmental biology for decades to come.
Topics: Animals; Body Patterning; Vertebrates; Embryonic Development; Gene Expression Regulation, Developmental; Morphogenesis; Somites
PubMed: 38729680
DOI: 10.1016/bs.ctdb.2024.01.003 -
Developmental Biology Apr 2024Cephalochordates occupy a key phylogenetic position for deciphering the origin and evolution of chordates, since they diverged earlier than urochordates and vertebrates....
Cephalochordates occupy a key phylogenetic position for deciphering the origin and evolution of chordates, since they diverged earlier than urochordates and vertebrates. The notochord is the most prominent feature of chordates. The amphioxus notochord features coin-shaped cells bearing myofibrils. Notochord-derived hedgehog signaling contributes to patterning of the dorsal nerve cord, as in vertebrates. However, properties of constituent notochord cells remain unknown at the single-cell level. We examined these properties using Iso-seq analysis, single-cell RNA-seq analysis, and in situ hybridization (ISH). Gene expression profiles broadly categorize notochordal cells into myofibrillar cells and non-myofibrillar cells. Myofibrillar cells occupy most of the central portion of the notochord, and some cells extend the notochordal horn to both sides of the ventral nerve cord. Some notochord myofibrillar genes are not expressed in myotomes, suggesting an occurrence of myofibrillar genes that are preferentially expressed in notochord. On the other hand, non-myofibrillar cells contain dorsal, lateral, and ventral Müller cells, and all three express both hedgehog and Brachyury. This was confirmed by ISH, although expression of hedgehog in ventral Müller cells was minimal. In addition, dorsal Müller cells express neural transmission-related genes, suggesting an interaction with nerve cord. Lateral Müller cells express hedgehog and other signaling-related genes, suggesting an interaction with myotomes positioned lateral to the notochord. Ventral Müller cells also expressed genes for FGF- and EGF-related signaling, which may be associated with development of endoderm, ventral to the notochord. Lateral Müller cells were intermediate between dorsal/ventral Müller cells. Since vertebrate notochord contributes to patterning and differentiation of ectoderm (nerve cord), mesoderm (somite), and endoderm, this investigation provides evidence that an ancestral or original form of vertebrate notochord is present in extant cephalochordates.
Topics: Animals; Phylogeny; Lancelets; Notochord; Single-Cell Gene Expression Analysis; Hedgehog Proteins; Vertebrates; Gene Expression Regulation, Developmental
PubMed: 38224933
DOI: 10.1016/j.ydbio.2024.01.003 -
Development (Cambridge, England) Feb 2024Early organogenesis represents a key step in animal development, during which pluripotent cells diversify to initiate organ formation. Here, we sampled 300,000...
Early organogenesis represents a key step in animal development, during which pluripotent cells diversify to initiate organ formation. Here, we sampled 300,000 single-cell transcriptomes from mouse embryos between E8.5 and E9.5 in 6-h intervals and combined this new dataset with our previous atlas (E6.5-E8.5) to produce a densely sampled timecourse of >400,000 cells from early gastrulation to organogenesis. Computational lineage reconstruction identified complex waves of blood and endothelial development, including a new programme for somite-derived endothelium. We also dissected the E7.5 primitive streak into four adjacent regions, performed scRNA-seq and predicted cell fates computationally. Finally, we defined developmental state/fate relationships by combining orthotopic grafting, microscopic analysis and scRNA-seq to transcriptionally determine cell fates of grafted primitive streak regions after 24 h of in vitro embryo culture. Experimentally determined fate outcomes were in good agreement with computationally predicted fates, demonstrating how classical grafting experiments can be revisited to establish high-resolution cell state/fate relationships. Such interdisciplinary approaches will benefit future studies in developmental biology and guide the in vitro production of cells for organ regeneration and repair.
Topics: Mice; Animals; Cell Differentiation; Gastrulation; Organogenesis; Primitive Streak; Endothelium; Embryo, Mammalian; Mammals
PubMed: 37982461
DOI: 10.1242/dev.201867 -
The FEBS Journal Nov 2023Multitudes of organisms display metameric compartmentalization of their body plan. Segmentation of these compartments happens sequentially in diverse phyla. In several...
Multitudes of organisms display metameric compartmentalization of their body plan. Segmentation of these compartments happens sequentially in diverse phyla. In several sequentially segmenting species, periodically active molecular clocks and signaling gradients have been found. The clocks are proposed to control the timing of segmentation, while the gradients are proposed to instruct the positions of segment boundaries. However, the identity of the clock and gradient molecules differs across species. Furthermore, sequential segmentation of a basal chordate, Amphioxus, continues at late stages when the small tail bud cell population cannot establish long-range signaling gradients. Thus, it remains to be explained how a conserved morphological trait (i.e., sequential segmentation) is achieved by using different molecules or molecules with different spatial profiles. Here, we first focus on sequential segmentation of somites in vertebrate embryos and then draw parallels with other species. Thereafter, we propose a candidate design principle that has the potential to answer this puzzling question.
Topics: Animals; Vertebrates; Signal Transduction; Logic; Somites; Body Patterning; Gene Expression Regulation, Developmental
PubMed: 37422856
DOI: 10.1111/febs.16899 -
Biochemical Society Transactions Jun 2024Reproducible tissue morphology is a fundamental feature of embryonic development. To ensure such robustness during tissue morphogenesis, inherent noise in biological... (Review)
Review
Reproducible tissue morphology is a fundamental feature of embryonic development. To ensure such robustness during tissue morphogenesis, inherent noise in biological processes must be buffered. While redundant genes, parallel signaling pathways and intricate network topologies are known to reduce noise, over the last few years, mechanical properties of tissues have been shown to play a vital role. Here, taking the example of somite shape changes, I will discuss how tissues are highly plastic in their ability to change shapes leading to increased precision and reproducibility.
Topics: Animals; Embryonic Development; Morphogenesis; Humans; Somites; Signal Transduction; Gene Expression Regulation, Developmental
PubMed: 38716859
DOI: 10.1042/BST20230173 -
Developmental Dynamics : An Official... Apr 2024Noncanonical Wnts are morphogens that can elevate intracellular Ca, activate the Ca/calmodulin-dependent protein kinase, CaMKII, and promote cell movements during...
BACKGROUND
Noncanonical Wnts are morphogens that can elevate intracellular Ca, activate the Ca/calmodulin-dependent protein kinase, CaMKII, and promote cell movements during vertebrate gastrulation.
RESULTS
Zebrafish express seven CaMKII genes during embryogenesis; two of these, camk2b1 and camk2g1, are necessary for convergent extension (CE) cell movements. CaMKII morphant phenotypes were observed as early as epiboly. At the 1-3 somite stage, neuroectoderm and paraxial cells remained unconverged in both morphants. Later, somites lacked their stereotypical shape and were wider, more closely spaced, and body gap angles increased. At 24hpf, somite compression and notochord undulation coincided with a shorter and broader body axis. A camk2b1 crispant was generated which phenocopied the camk2b1 morphant. The levels of cell proliferation, apoptosis and paraxial and neuroectodermal markers were unchanged in morphants. Hyperactivation of CaMKII during gastrulation by transient pharmacological intervention (thapsigargin) also caused CE defects. Mosaically expressed dominant-negative CaMKII recapitulated these phenotypes and showed significant midline bifurcation. Finally, the introduction of CaMKII partially rescued Wnt11 morphant phenotypes.
CONCLUSIONS
Overall, these data support a model whereby cyclically activated CaMKII encoded from two genes enables cell migration during the process of CE.
Topics: Animals; Zebrafish; Zebrafish Proteins; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Gastrulation; Cell Movement
PubMed: 37860955
DOI: 10.1002/dvdy.665 -
Comparative Biochemistry and... Jan 2024The mixture of agrochemicals can be made to improve pest control or accidentally. In this way, the effects on non-target organisms are a critical aspect of the...
The mixture of agrochemicals can be made to improve pest control or accidentally. In this way, the effects on non-target organisms are a critical aspect of the environment and heath. Thus, this work aimed to show how a mixture of pyriproxyfen, and glyphosate can impair biochemical routes and embryonic development. Zebrafish embryos 0-72 hpf were exposed to 0.001-1 μg/mL of pyriproxyfen, glyphosate, and a mixture of both pesticides. The ADMETox was evaluated in silico. The FET-test was used to estimate teratogenic effects. The biochemical effects were estimated using AChE, SOD, and CAT as parameters. ROS generation was estimated using 30 μM HDCF-DA and 5 μM DHE. The ADMETox reveals that intestinal absorption and P-glycoprotein are the main sites for PPx and Gly adsorption. The distribution parameters were diverse. PPx + Gly at 0.1 μg/mL leads to 50 % of lethality and at 1 μg/mL 100 % of lethality. PPx + Gly leads to a 22 % of lack of somite formation at 1 μg/mL. The heart rate was reduced by >10 % in all concentrations tested. The AChE has a decrease with IC 19.6 μM and IC 261.5 μM. SOD showed a reduction of 28 % to PPx and CAT was reduced by 58 % to PPx + Gly and Gly at 1 μg/mL. Glyphosate does not increase unspecific ROS generation. The superoxide generation was 2× higher in the PPx + Gly at 1 μg/mL. Summarily, was observed that the mixture of PPx + Gly potentiated the toxic effects. This finding suggests a possible synergism between the PPx and Gly even at lower concentrations.
Topics: Animals; Zebrafish; Reactive Oxygen Species; Superoxide Dismutase; Glyphosate
PubMed: 37844749
DOI: 10.1016/j.cbpc.2023.109766 -
Biotechnic & Histochemistry : Official... Nov 2023Nausea and vomiting during pregnancy are common problems and prolonged pharmacological treatment often is needed; however, the teratogenic effects of anti-emetic drugs...
Nausea and vomiting during pregnancy are common problems and prolonged pharmacological treatment often is needed; however, the teratogenic effects of anti-emetic drugs on neural tube (NT) development are not clear. We investigated the effects of different doses of metoclopramide on NT development in 48 and 72 h chick embryos using an argyrophilic nucleolar organizing region (AgNOR) staining method. We used 150 fertile, specific pathogen-free eggs incubated for 28 h, then randomly divided into five equal groups: group A, sham control was administered 0.9% saline; groups B - E were administered 0.15 mgegg, 0.3 mg/egg, 0.6 mg/egg and 1.2 mg/egg, respectively. Half of the eggs in each group were taken from the incubator at 48 h incubation and the other half at 72 h incubation. After incubation, eggs were opened, embryos were dissected from their membranes, fixed with 10% formalin and examined by light microscopy. The NT status, i.e., open or closed, and somite number, crown-rump length, morphological features and gross developmental abnormalities were recorded. Excised embryos were sectioned and stained using hematoxylin and eosin or the AgNOR procedure and examined for morphology and histopathology. Delayed NT closure was observed in all 48 h drug exposed embryos, but in the 72 h groups, this occurred only in high-dose groups. Somite number was reduced significantly in groups C - E compared to the control group. Crown-rump length was decreased in both 48 and 72 h embryos. We found a decreased total AgNOR area:nuclear area ratio in 48 and 72 h embryos of all experimental groups. We found that metoclopramide delayed NT closure in chick embryos in a dose-dependent manner.
Topics: Animals; Chick Embryo; Neural Tube; Neural Tube Defects; Metoclopramide; Embryonic Development
PubMed: 36843544
DOI: 10.1080/10520295.2023.2182913 -
Chemistry & Biodiversity Aug 2023Varronia curassavica displays anti-inflammatory, antiulcerogenic, and antioxidant activities. Herein, we employed new UHPLC -UV green chromatographic methods for the...
Varronia curassavica displays anti-inflammatory, antiulcerogenic, and antioxidant activities. Herein, we employed new UHPLC -UV green chromatographic methods for the analysis of in vitro antioxidant and anti-inflammatory activities of V. curassavica and its embryotoxicity in Zebrafish. Cordialin A, brickellin, and artemetin were purified from the ethanol (EtOH) extract of V. Curassavica leaves and identified using spectrometric techniques. In line with Green Analytical Chemistry principles, the proposed UHPLC methods involve the use of ethanol as organic modifier with low mobile phase consumption, and without sample pretreatment (OLE-UHPLC-UV). The application of the Agree and HPLC-EAT tools for greenness assessment yielded this pattern: HPLC-UV (reference)
somites, and eyes, mainly in higher extract concentrations. Extracts and brickellin exhibited higher antioxidant activity in the DPPH⋅ assay, while brickellin+artemetin displayed higher antioxidant activity compared to the extracts and isolated flavones in the O ⋅ and HOCl/OCl scavenging assays. Cordialin A and brickellin exhibited low COX-1, COX-2, and phospholipase A inhibition. Topics: Animals; Plant Extracts; Antioxidants; Zebrafish; Anti-Inflammatory Agents; Plant Leaves; Ethanol
PubMed: 37402173
DOI: 10.1002/cbdv.202300329 -
Cells & Development Dec 2023Neural induction by cell-cell signaling was discovered a century ago by the organizer transplantations of Spemann and Mangold in amphibians. Spemann later found that...
Neural induction by cell-cell signaling was discovered a century ago by the organizer transplantations of Spemann and Mangold in amphibians. Spemann later found that early dorsal blastopore lips induced heads and late organizers trunk-tail structures. Identifying region-specific organizer signals has been a driving force in the progress of animal biology. Head induction in the absence of trunk is designated archencephalic differentiation. Two specific head inducers, Cerberus and Insulin-like growth factors (IGFs), that induce archencephalic brain but not trunk-tail structures have been described previously. However, whether these two signals interact with each other had not been studied to date and was the purpose of the present investigation. It was found that Cerberus, a multivalent growth factor antagonist that inhibits Nodal, BMP and Wnt signals, strongly cooperated with IGF2, a growth factor that provides a positive signal through tyrosine kinase IGF receptors that activate MAPK and other pathways. The ectopic archencephalic structures induced by the combination of Cerberus and IGF2 are of higher frequency and larger than either one alone. They contain brain, a cyclopic eye and multiple olfactory placodes, without trace of trunk structures such as notochord or somites. A dominant-negative secreted IGF receptor 1 blocked Cerberus activity, indicating that endogenous IGF signals are required for ectopic brain formation. In a sensitized embryonic system, in which embryos were depleted of β-catenin, IGF2 did not by itself induce neural tissue while in combination with Cerberus it greatly enhanced formation of circular brain structures expressing the anterior markers Otx2 and Rx2a, but not spinal cord or notochord markers. The main conclusion of this work is that IGF provides a positive signal initially uniformly expressed throughout the embryo that potentiates the effect of an organizer-specific negative signal mediated by Cerberus. The results are discussed in the context of the history of neural induction.
PubMed: 38109998
DOI: 10.1016/j.cdev.2023.203897