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Cell Stem Cell Sep 2018The mesoderm arises from pluripotent epiblasts and differentiates into multiple lineages; however, the underlying molecular mechanisms are unclear. Tbx6 is enriched in...
The mesoderm arises from pluripotent epiblasts and differentiates into multiple lineages; however, the underlying molecular mechanisms are unclear. Tbx6 is enriched in the paraxial mesoderm and is implicated in somite formation, but its function in other mesoderms remains elusive. Here, using direct reprogramming-based screening, single-cell RNA-seq in mouse embryos, and directed cardiac differentiation in pluripotent stem cells (PSCs), we demonstrated that Tbx6 induces nascent mesoderm from PSCs and determines cardiovascular and somite lineage specification via its temporal expression. Tbx6 knockout in mouse PSCs using CRISPR/Cas9 technology inhibited mesoderm and cardiovascular differentiation, whereas transient Tbx6 expression induced mesoderm and cardiovascular specification from mouse and human PSCs via direct upregulation of Mesp1, repression of Sox2, and activation of BMP/Nodal/Wnt signaling. Notably, prolonged Tbx6 expression suppressed cardiac differentiation and induced somite lineages, including skeletal muscle and chondrocytes. Thus, Tbx6 is critical for mesoderm induction and subsequent lineage diversification.
Topics: Animals; Cardiovascular System; Cell Differentiation; Cell Lineage; Cells, Cultured; Humans; Male; Mesoderm; Mice; Mice, Inbred ICR; Mice, Transgenic; Pluripotent Stem Cells; Somites; T-Box Domain Proteins; Transcription Factors
PubMed: 30100166
DOI: 10.1016/j.stem.2018.07.001 -
Development (Cambridge, England) Apr 2017Mesoderm induction begins during gastrulation. Recent evidence from several vertebrate species indicates that mesoderm induction continues after gastrulation in...
FGF and canonical Wnt signaling cooperate to induce paraxial mesoderm from tailbud neuromesodermal progenitors through regulation of a two-step epithelial to mesenchymal transition.
Mesoderm induction begins during gastrulation. Recent evidence from several vertebrate species indicates that mesoderm induction continues after gastrulation in neuromesodermal progenitors (NMPs) within the posteriormost embryonic structure, the tailbud. It is unclear to what extent the molecular mechanisms of mesoderm induction are conserved between gastrula and post-gastrula stages of development. Fibroblast growth factor (FGF) signaling is required for mesoderm induction during gastrulation through positive transcriptional regulation of the T-box transcription factor We find in zebrafish that FGF is continuously required for paraxial mesoderm (PM) induction in post-gastrula NMPs. FGF signaling represses the NMP markers () and through regulation of and , thereby committing cells to a PM fate. FGF-mediated PM induction in NMPs functions in tight coordination with canonical Wnt signaling during the epithelial to mesenchymal transition (EMT) from NMP to mesodermal progenitor. Wnt signaling initiates EMT, whereas FGF signaling terminates this event. Our results indicate that germ layer induction in the zebrafish tailbud is not a simple continuation of gastrulation events.
Topics: Amino Acid Sequence; Animals; Epithelial-Mesenchymal Transition; Fibroblast Growth Factors; Gastrula; Imaging, Three-Dimensional; Mesoderm; Nervous System; Stem Cells; T-Box Domain Proteins; Tail; Vimentin; Wnt Signaling Pathway; Xenopus laevis; Zebrafish; Zebrafish Proteins
PubMed: 28242612
DOI: 10.1242/dev.143578 -
International Journal of Molecular... Jan 2021Skeletal disorders, such as osteoarthritis and bone fractures, are among the major conditions that can compromise the quality of daily life of elderly individuals. To... (Review)
Review
Skeletal disorders, such as osteoarthritis and bone fractures, are among the major conditions that can compromise the quality of daily life of elderly individuals. To treat them, regenerative therapies using skeletal cells have been an attractive choice for patients with unmet clinical needs. Currently, there are two major strategies to prepare the cell sources. The first is to use induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs), which can recapitulate the skeletal developmental process and differentiate into various skeletal cells. Skeletal tissues are derived from three distinct origins: the neural crest, paraxial mesoderm, and lateral plate mesoderm. Thus, various protocols have been proposed to recapitulate the sequential process of skeletal development. The second strategy is to extract stem cells from skeletal tissues. In addition to mesenchymal stem/stromal cells (MSCs), multiple cell types have been identified as alternative cell sources. These cells have distinct multipotent properties allowing them to differentiate into skeletal cells and various potential applications for skeletal regeneration. In this review, we summarize state-of-the-art research in stem cell differentiation based on the understanding of embryogenic skeletal development and stem cells existing in skeletal tissues. We then discuss the potential applications of these cell types for regenerative medicine.
Topics: Animals; Bone Development; Bone and Bones; Cell Differentiation; Disease Models, Animal; Embryo, Mammalian; Embryonic Development; Embryonic Stem Cells; Fractures, Bone; Humans; Induced Pluripotent Stem Cells; Mesenchymal Stem Cells; Mesoderm; Neural Crest; Osteoarthritis; Osteoblasts; Regenerative Medicine; Stem Cell Transplantation
PubMed: 33573345
DOI: 10.3390/ijms22031404 -
Nature Reviews. Genetics May 2008The body axis of vertebrates is composed of a serial repetition of similar anatomical modules that are called segments or metameres. This particular mode of organization... (Review)
Review
The body axis of vertebrates is composed of a serial repetition of similar anatomical modules that are called segments or metameres. This particular mode of organization is especially conspicuous at the level of the periodic arrangement of vertebrae in the spine. The segmental pattern is established during embryogenesis when the somites--the embryonic segments of vertebrates--are rhythmically produced from the paraxial mesoderm. This process involves the segmentation clock, which is a travelling oscillator that interacts with a maturation wave called the wavefront to produce the periodic series of somites. Here, we review our current understanding of the segmentation process in vertebrates.
Topics: Animals; Biological Clocks; Body Patterning; Humans; Mesoderm; Somites; Spine; Vertebrates
PubMed: 18414404
DOI: 10.1038/nrg2320 -
Current Opinion in Genetics &... Aug 2005The generation of somites, and the subsequent formation of their major derivatives, muscle-, cartilage-, dermis- and tendon-cell lineages, is tightly orchestrated and,... (Review)
Review
The generation of somites, and the subsequent formation of their major derivatives, muscle-, cartilage-, dermis- and tendon-cell lineages, is tightly orchestrated and, to different extents, these are also mutually supporting processes. They involve complex and timely reorganizations of the paraxial mesoderm, such as multiple phases of epithelial-mesenchymal rearrangements and vice-versa, cellular movements and migrations, and modifications of both cell shape and cell cycle properties. These morphogenetic changes are triggered by local environmental signals and are tightly associated to a genetic program imparting cell-specific fates. Elucidating these signals and their downstream effectors, in addition to determining the state of specification of responsive cell subsets and that of single progenitors in the various domains, is only beginning.
Topics: Animals; Cell Cycle; Cell Differentiation; Cell Movement; Gene Expression Regulation, Developmental; Signal Transduction; Somites
PubMed: 15950454
DOI: 10.1016/j.gde.2005.05.004 -
Genes & Development Dec 1999Wnt3a encodes a signal that is expressed in the primitive streak of the gastrulating mouse embryo and is required for paraxial mesoderm development. In its absence cells...
Wnt3a encodes a signal that is expressed in the primitive streak of the gastrulating mouse embryo and is required for paraxial mesoderm development. In its absence cells adopt ectopic neural fates. Embryos lacking the T-box-containing transcription factors, Brachyury or Tbx6, also lack paraxial mesoderm. Here we show that Brachyury is specifically down-regulated in Wnt3a mutants in cells fated to form paraxial mesoderm. Transgenic analysis of the T promoter identifies T (Brachyury) as a direct transcriptional target of the Wnt signaling pathway. Our results suggest that Wnt3a, signaling via Brachyury, modulates a balance between mesodermal and neural cell fates during gastrulation.
Topics: Animals; Embryonic and Fetal Development; Fetal Proteins; Gastrula; Gene Expression Regulation, Developmental; Heterozygote; Homozygote; Mesoderm; Mice; Mice, Knockout; Mice, Transgenic; Mutagenesis, Site-Directed; Promoter Regions, Genetic; Proteins; Recombinant Proteins; Signal Transduction; T-Box Domain Proteins; Wnt Proteins; Wnt3 Protein; Wnt3A Protein; beta-Galactosidase
PubMed: 10617567
DOI: 10.1101/gad.13.24.3185 -
Developmental Biology Apr 1995During vertebrate embryogenesis, cells from the paraxial mesoderm coalesce in a rostral-to-caudal progression to form the somites. Subsequent compartmentalization of the...
During vertebrate embryogenesis, cells from the paraxial mesoderm coalesce in a rostral-to-caudal progression to form the somites. Subsequent compartmentalization of the somites yields the sclerotome, myotome, and dermatome, which give rise to the axial skeleton, axial musculature, and dermis, respectively. Recently, we cloned a novel basic helix-loop-helix (bHLH) protein, called scleraxis, which is expressed in the sclerotome, in mesenchymal precursors of bone and cartilage, and in connective tissues. Here we report the cloning of a bHLH protein, called paraxis, which is nearly identical to scleraxis within the bHLH region but diverges in its amino and carboxyl termini. During mouse embryogenesis, paraxis transcripts are first detected at about Day 7.5 postcoitum within primitive mesoderm lying posterior to the head and heart primordia. Subsequently, paraxis expression progresses caudally through the paraxial mesoderm, immediately preceding somite formation. Paraxis is expressed at high levels in newly formed somites before the first detectable expression of the myogenic bHLH genes, and as the somite becomes compartmentalized, paraxis becomes downregulated in the myotome. Paraxis and scleraxis are coexpressed in the sclerotome, but paraxis expression declines soon after sclerotome formation, whereas scleroaxis expression increases in the sclerotome and its derivatives. The sequential expression of paraxis and scleraxis in the paraxial mesoderm and somites suggests that these bHLH proteins may comprise part of a regulatory pathway involved in patterning of the paraxial mesoderm and in the establishment of somitic cell lineages.
Topics: Amino Acid Sequence; Animals; Base Sequence; Basic Helix-Loop-Helix Transcription Factors; Cloning, Molecular; DNA-Binding Proteins; Helix-Loop-Helix Motifs; Mesoderm; Mice; Molecular Sequence Data; Vertebrates
PubMed: 7729571
DOI: 10.1006/dbio.1995.1081 -
Mechanisms of Development Oct 2002Frizzled (fz) genes encode receptors for the Wnt signaling pathway. We describe a novel fz gene, zebrafish fz7b. Maternal fz7b mRNA is detectable by RT-PCR. Embryonic...
Frizzled (fz) genes encode receptors for the Wnt signaling pathway. We describe a novel fz gene, zebrafish fz7b. Maternal fz7b mRNA is detectable by RT-PCR. Embryonic fz7b is widely distributed in early epiboly stage embryos. By shield stage, expression appears enriched around the blastoderm margin. During epiboly, expression becomes restricted to the prechordal plate, presumptive midbrain and hindbrain and paraxial mesoderm. As somites form, labeling is briefly present in a segmental pattern. By mid-somitogensis, expression is particularly enriched in the forebrain, the forebrain-midbrain boundary, and the anterior hindbrain, but appears at lower levels throughout much of the rostral CNS. The CNS expression is at ventral and medial positions. The paraxial mesoderm expression becomes restricted to the tailbud. This pattern continues through 26 h. At 48 h, weak expression is seen in the pharyngeal arches and developing fin.
Topics: Amino Acid Sequence; Animals; Central Nervous System; Expressed Sequence Tags; Gene Expression Regulation, Developmental; Humans; Mesoderm; Molecular Sequence Data; Neural Crest; Phylogeny; Prosencephalon; RNA, Messenger; Receptors, Cell Surface; Reverse Transcriptase Polymerase Chain Reaction; Sequence Homology, Amino Acid; Time Factors; Tissue Distribution; Zebrafish; Zebrafish Proteins
PubMed: 12351181
DOI: 10.1016/s0925-4773(02)00221-6 -
Development (Cambridge, England) Apr 2004Coordination of morphogenesis and cell proliferation is essential during development. In Xenopus, cell divisions are rapid and synchronous early in development but then...
Coordination of morphogenesis and cell proliferation is essential during development. In Xenopus, cell divisions are rapid and synchronous early in development but then slow and become spatially restricted during gastrulation and neurulation. One tissue that transiently stops dividing is the paraxial mesoderm, a dynamically mobile tissue that forms the somites and body musculature of the embryo. We have found that cessation of cell proliferation is required for the proper positioning and segmentation of the paraxial mesoderm as well as the complete elongation of the Xenopus embryo. Instrumental in this cell cycle arrest is Wee2, a Cdk inhibitory kinase that is expressed in the paraxial mesoderm from mid-gastrula stages onwards. Morpholino-mediated depletion of Wee2 increases the mitotic index of the paraxial mesoderm and this results in the failure of convergent extension and somitogenesis in this tissue. Similar defects are observed if the cell cycle is inappropriately advanced by other mechanisms. Thus, the low mitotic index of the paraxial mesoderm plays an essential function in the integrated cell movements and patterning of this tissue.
Topics: Animals; Cell Cycle; Embryo, Nonmammalian; Mesoderm; Mitosis; Protein-Tyrosine Kinases; Somites; Xenopus; Xenopus Proteins
PubMed: 15084456
DOI: 10.1242/dev.01054 -
Developmental Biology Mar 2015Activation of the Pax2 gene marks the intermediate mesoderm shortly after gastrulation, as the mesoderm becomes compartmentalized into paraxial, intermediate, and...
Activation of the Pax2 gene marks the intermediate mesoderm shortly after gastrulation, as the mesoderm becomes compartmentalized into paraxial, intermediate, and lateral plate. Using an EGFP knock-in allele of Pax2 to identify and sort cells of the intermediate mesodermal lineage, we compared gene expression patterns in EGFP positive cells that were heterozygous or homozygous null for Pax2. Thus, we identified critical regulators of intermediate mesoderm and kidney development whose expression depended on Pax2 function. In cell culture models, Pax2 is thought to recruit epigenetic modifying complex to imprint activating histone methylation marks through interactions with the adaptor protein PTIP. In kidney organ culture, conditional PTIP deletion showed that many Pax2 target genes, which were activated early in renal progenitor cells, remained on once activated, whereas Pax2 target genes expressed later in kidney development were unable to be fully activated without PTIP. In Pax2 mutants, we also identified a set of genes whose expression was up-regulated in EGFP positive cells and whose expression was consistent with a cell fate transformation to paraxial mesoderm and its derivatives. These data provide evidence that Pax2 specifies the intermediate mesoderm and renal epithelial cells through epigenetic mechanisms and in part by repressing paraxial mesodermal fate.
Topics: Animals; Blotting, Western; Carrier Proteins; DNA Primers; DNA-Binding Proteins; Flow Cytometry; Gene Expression Regulation; Gene Knock-In Techniques; Green Fluorescent Proteins; In Situ Hybridization; Kidney; Mesoderm; Mice; Microarray Analysis; Nuclear Proteins; PAX2 Transcription Factor; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Stem Cells
PubMed: 25617721
DOI: 10.1016/j.ydbio.2015.01.005