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Developmental Biology Sep 2017The physical basis of morphogenesis is a fascinating concern that has been a longstanding interest of developmental biologists. In this review, I attempt to incorporate... (Review)
Review
The physical basis of morphogenesis is a fascinating concern that has been a longstanding interest of developmental biologists. In this review, I attempt to incorporate earlier and recent biophysical concepts and data to explain basic features of early limb bud morphogenesis. In particular, I discuss the influence of mesenchymal cohesion and physical properties that might contribute to phase separation of the bud from the lateral plate, the possibility that the early dorsoventral limb bud axis is moulded by the surface ectoderm, and endogenous electric fields that might contribute to oriented cell movements which generate the early limb bud. A combination of quantitative biophysical experimentation and modelling will likely advance this field.
Topics: Animals; Biophysical Phenomena; Cell Movement; Cell Polarity; Electricity; Limb Buds; Mesoderm; Morphogenesis
PubMed: 28669818
DOI: 10.1016/j.ydbio.2017.06.034 -
Developmental Biology Oct 2021To date, the role of miRNAs on pluripotency and differentiation of ESCs into specific lineages has been studied extensively. However, the specific role of miRNAs during...
To date, the role of miRNAs on pluripotency and differentiation of ESCs into specific lineages has been studied extensively. However, the specific role of miRNAs during lateral and paraxial mesoderm cell fate decision is still unclear. To address this, we firstly determined miRNA profile of mouse ESCs differentiating towards lateral and paraxial lineages which were detected using Flk1 and PDGFαR antibodies, and of myogenic and hematopoietic differentiation potential of purified paraxial and lateral mesodermal cells within these populations. miRNAs associated with lateral and paraxial mesoderm, and their targets were identified using bioinformatics tools. The targets of the corresponding miRNAs were validated after transfection into mouse ESCs. The roles of the selected miRNAs in lateral, and paraxial mesoderm formation were assessed along with hematopoietic and myogenic differentiation capacity. Among the miRNAs, mmu-miR-126a-3p, mmu-miR-335-5p and mmu-miR-672-5p, upregulated in lateral mesoderm cells, and mmu-miR-10b-5p, mmu-miR-196a-5p and mmu-miR-615-3p, upregulated in paraxial mesoderm cells. While transient co-transfection of mmu-miR-126a-3p, mmu-miR-335-5p and mmu-miR-672-5p increased the number of lateral mesodermal cells, co-transfection of mmu-miR-10b-5p, mmu-miR-196a-5p and mmu-miR-615-3p increased the number of paraxial mesodermal cells. Moreover, differentiation potential of the lateral mesodermal cells into hematopoietic cell lineage increased upon co-transfection of mmu-miR-126a-3p, mmu-miR-335-5p and mmu-miR-672-5p and differentiation potential of the paraxial mesodermal cells into skeletal muscle lineage were increased upon co-transfection of mmu-miR-10b-5p, mmu-miR-196a-5p and mmu-miR-615-3p. In conclusion, we determined the miRNA profile of lateral and paraxial mesodermal cells and co-transfection of miRNAs increased differentiation potential of both lateral and paraxial mesodermal cells transiently.
Topics: Animals; Cell Differentiation; Computational Biology; Embryoid Bodies; Embryonic Stem Cells; Hematopoiesis; Mesoderm; Mice; MicroRNAs; Muscle Development; Transfection; Up-Regulation
PubMed: 34245726
DOI: 10.1016/j.ydbio.2021.07.002 -
ELife Jan 2022During the development of the vertebrate embryo, segmented structures called somites are periodically formed from the presomitic mesoderm (PSM) and give rise to the...
During the development of the vertebrate embryo, segmented structures called somites are periodically formed from the presomitic mesoderm (PSM) and give rise to the vertebral column. While somite formation has been studied in several animal models, it is less clear how well this process is conserved in humans. Recent progress has made it possible to study aspects of human paraxial mesoderm (PM) development such as the human segmentation clock using human pluripotent stem cells (hPSCs); however, somite formation has not been observed in these monolayer cultures. Here, we describe the generation of human PM organoids from hPSCs (termed Somitoids), which recapitulate the molecular, morphological, and functional features of PM development, including formation of somite-like structures . Using a quantitative image-based screen, we identify critical parameters such as initial cell number and signaling modulations that reproducibly yielded formation of somite-like structures in our organoid system. In addition, using single-cell RNA-sequencing and 3D imaging, we show that PM organoids both transcriptionally and morphologically resemble their counterparts and can be differentiated into somite derivatives. Our organoid system is reproducible and scalable, allowing for the systematic and quantitative analysis of human spine development and disease .
Topics: Animals; Cell Differentiation; Humans; Mesoderm; Organoids; Pluripotent Stem Cells; Somites
PubMed: 35088712
DOI: 10.7554/eLife.68925 -
Development (Cambridge, England) Sep 2015Neuromesodermal progenitors (NMps) contribute to both the elongating spinal cord and the adjacent paraxial mesoderm. It has been assumed that these cells arise as a... (Review)
Review
Neuromesodermal progenitors (NMps) contribute to both the elongating spinal cord and the adjacent paraxial mesoderm. It has been assumed that these cells arise as a result of patterning of the anterior neural plate. However, as the molecular mechanisms that specify NMps in vivo are uncovered, and as protocols for generating these bipotent cells from mouse and human pluripotent stem cells in vitro are established, the emerging data suggest that this view needs to be revised. Here, we review the characteristics, regulation, in vitro derivation and in vivo induction of NMps. We propose that these cells arise within primitive streak-associated epiblast via a mechanism that is separable from that which establishes neural fate in the anterior epiblast. We thus argue for the existence of two distinct routes for making central nervous system progenitors.
Topics: Animals; Body Patterning; Embryo, Mammalian; Humans; Mesoderm; Neural Stem Cells; Signal Transduction; Spinal Cord; Stem Cells
PubMed: 26329597
DOI: 10.1242/dev.119768 -
Current Topics in Developmental Biology 2024In avian and mammalian embryos the "organizer" property associated with neural induction of competent ectoderm into a neural plate and its subsequent patterning into... (Review)
Review
In avian and mammalian embryos the "organizer" property associated with neural induction of competent ectoderm into a neural plate and its subsequent patterning into rostro-caudal domains resides at the tip of the primitive streak before neurulation begins, and before a morphological Hensen's node is discernible. The same region and its later derivatives (like the notochord) also have the ability to "dorsalize" the adjacent mesoderm, for example by converting lateral plate mesoderm into paraxial (pre-somitic) mesoderm. Both neural induction and dorsalization of the mesoderm involve inhibition of BMP, and the former also requires other signals. This review surveys the key experiments done to elucidate the functions of the organizer and the mechanisms of neural induction in amniotes. We conclude that the mechanisms of neural induction in amniotes and anamniotes are likely to be largely the same; apparent differences are likely to be due to differences in experimental approaches dictated by embryo topology and other practical constraints. We also discuss the relationships between "neural induction" assessed by grafts of the organizer and normal neural plate development, as well as how neural induction relates to the generation of neuronal cells from embryonic and other stem cells in vitro.
Topics: Animals; Mesoderm; Somites; Embryonic Induction; Birds; Mammals
PubMed: 38556458
DOI: 10.1016/bs.ctdb.2024.02.004 -
Cold Spring Harbor Protocols Nov 2022Marginal zone explants from embryos can be used to expose cell behaviors and tissue movements that normally operate in dorsal tissues. Dorsal explants comprise the...
Marginal zone explants from embryos can be used to expose cell behaviors and tissue movements that normally operate in dorsal tissues. Dorsal explants comprise the diverse set of progenitor cells found in dorsal tissues including mesendoderm, head mesoderm, prechordal mesoderm, endoderm with bottle cells, axial mesoderm of the prospective notochord, paraxial mesoderm of the somites, lateral plate mesoderm, neural ectoderm, and ectoderm. Unlike an organoid, the dorsal marginal zone (DMZ) explant is "organotypic" in that microsurgery does not disrupt native tissue organization beyond manipulations needed to dissect the tissue from the embryo. An organotypic early gastrula DMZ explant preserves boundaries and close tissue associations in the native marginal zone. Depending on the stage, patterning and cell identities can be maintained in explants and tissue isolates. Local cell movements and behaviors may also be preserved; however, the large-scale biomechanical impact of their collective movements may be altered from those in the native marginal zone. For instance, involution is typically inhibited in the DMZ explant, precluding the two-layer association of mesoderm and prospective neural ectoderm normally achieved during gastrulation. DMZ explants may be mounted and imaged in a variety of ways, exposing interesting cell behaviors or collective movements such as mediolateral cell intercalation in the axial and paraxial mesoderm, apical constriction of bottle cells, and directional migration of mesendoderm. The flattened DMZ explant can also be used to study emergence of new tissue-defining boundaries such as the notochord-somite boundary, the ectoderm-mesoderm boundary, and the mesendoderm-mesoderm boundary.
Topics: Animals; Gastrula; Prospective Studies; Mesoderm; Xenopus laevis; Ectoderm
PubMed: 35577522
DOI: 10.1101/pdb.prot097360 -
Cells & Development Dec 2021In vertebrate embryos the presomitic mesoderm becomes progressively segmented into somites at the anterior end while extending along the anterior-posterior axis. A...
In vertebrate embryos the presomitic mesoderm becomes progressively segmented into somites at the anterior end while extending along the anterior-posterior axis. A commonly adopted model to explain how this tissue elongates is that of posterior growth, driven in part by the addition of new cells from uncommitted progenitor populations in the tailbud. However, in zebrafish, much of somitogenesis is associated with an absence of overall volume increase, and posterior progenitors do not contribute new cells until the final stages of somitogenesis. Here, we perform a comprehensive 3D morphometric analysis of the paraxial mesoderm and reveal that extension is linked to a volumetric decrease and an increase in cell density. We also find that individual cells decrease in volume over successive somite stages. Live cell tracking confirms that much of this tissue deformation occurs within the presomitic mesoderm progenitor zone and is associated with non-directional rearrangement. Taken together, we propose a compaction-extension mechanism of tissue elongation that highlights the need to better understand the role tissue intrinsic and extrinsic forces in regulating morphogenesis.
Topics: Animals; Embryonic Development; Mesoderm; Morphogenesis; Somites; Zebrafish
PubMed: 34597846
DOI: 10.1016/j.cdev.2021.203748 -
DNA and Cell Biology Oct 2023Fibroblast growth factor (FGF) signaling is conserved from cnidaria to mammals (Ornitz and Itoh, 2022) and it regulates several critical processes such as... (Review)
Review
Fibroblast growth factor (FGF) signaling is conserved from cnidaria to mammals (Ornitz and Itoh, 2022) and it regulates several critical processes such as differentiation, proliferation, apoptosis, cell migration, and embryonic development. One pivotal process FGF signaling controls is the division of vertebrate paraxial mesoderm into repeated segmented units called somites (i.e., somitogenesis). Somite segmentation occurs periodically and sequentially in a head-to-tail manner, and lays down the plan for compartmentalized development of the vertebrate body axis (Gomez , 2008). These somites later give rise to vertebrae, tendons, and skeletal muscle. Somite segments form sequentially from the anterior end of the presomitic mesoderm (PSM). The periodicity of somite segmentation is conferred by the segmentation clock, comprising oscillatory expression of Hairy and enhancer-of-split (Her/Hes) genes in the PSM. The positional information for somite boundaries is instructed by the double phosphorylated extracellular signal-regulated kinase (ppERK) gradient, which is the relevant readout of FGF signaling during somitogenesis (Sawada , 2001; Delfini , 2005; Simsek and Ozbudak, 2018; Simsek , 2023). In this review, we summarize the crosstalk between the segmentation clock and FGF/ppERK gradient and discuss how that leads to periodic somite boundary formation. We also draw attention to outstanding questions regarding the interconnected roles of the segmentation clock and ppERK gradient, and close with suggested future directions of study.
Topics: Animals; Fibroblast Growth Factors; Somites; Mesoderm; Signal Transduction; Embryonic Development; Gene Expression Regulation, Developmental; Mammals
PubMed: 37462914
DOI: 10.1089/dna.2023.0226 -
Cell Reports Aug 2022Embryonic stem cells (ESCs) can adopt lineage-specific gene-expression programs by stepwise exposure to defined factors, resulting in the generation of functional cell...
Embryonic stem cells (ESCs) can adopt lineage-specific gene-expression programs by stepwise exposure to defined factors, resulting in the generation of functional cell types. Bulk and single-cell-based assays were employed to catalog gene expression, histone modifications, chromatin conformation, and accessibility transitions in ESC populations and individual cells acquiring a presomitic mesoderm fate and undergoing further specification toward myogenic and neurogenic lineages. These assays identified cis-regulatory regions and transcription factors presiding over gene-expression programs occurring at defined ESC transitions and revealed the presence of heterogeneous cell populations within discrete ESC developmental stages. The datasets were employed to identify previously unappreciated genomic elements directing the initial activation of Pax7 and myogenic and neurogenic gene-expression programs. This study provides a resource for the discovery of genomic and transcriptional features of pluripotent, mesoderm-induced ESCs and ESC-derived cell lineages.
Topics: Cell Differentiation; Embryonic Stem Cells; Gene Expression Regulation, Developmental; Mesoderm; Regulatory Sequences, Nucleic Acid; Transcriptome
PubMed: 35977485
DOI: 10.1016/j.celrep.2022.111219 -
Nature Communications Aug 2020Visceral organs, such as the lungs, stomach and liver, are derived from the fetal foregut through a series of inductive interactions between the definitive endoderm (DE)...
Visceral organs, such as the lungs, stomach and liver, are derived from the fetal foregut through a series of inductive interactions between the definitive endoderm (DE) and the surrounding splanchnic mesoderm (SM). While DE patterning is fairly well studied, the paracrine signaling controlling SM regionalization and how this is coordinated with epithelial identity is obscure. Here, we use single cell transcriptomics to generate a high-resolution cell state map of the embryonic mouse foregut. This identifies a diversity of SM cell types that develop in close register with the organ-specific epithelium. We infer a spatiotemporal signaling network of endoderm-mesoderm interactions that orchestrate foregut organogenesis. We validate key predictions with mouse genetics, showing the importance of endoderm-derived signals in mesoderm patterning. Finally, leveraging these signaling interactions, we generate different SM subtypes from human pluripotent stem cells (hPSCs), which previously have been elusive. The single cell data can be explored at: https://research.cchmc.org/ZornLab-singlecell .
Topics: Animals; Cell Lineage; Digestive System; Endoderm; Gene Expression Profiling; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Humans; Internet; Mesoderm; Mice, Inbred C57BL; Organogenesis; Signal Transduction; Single-Cell Analysis; Transcription Factors
PubMed: 32855417
DOI: 10.1038/s41467-020-17968-x