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Journal of Computational Biology : a... Jul 2019
Topics: Animals; Endoderm; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Genome; Mesoderm
PubMed: 31166788
DOI: 10.1089/cmb.2019.0097 -
The EMBO Journal Dec 1999In the amniote embryos, specification of skeletal myoblasts occurs in the paraxial mesoderm in response to a number of signaling molecules produced by neighboring... (Review)
Review
In the amniote embryos, specification of skeletal myoblasts occurs in the paraxial mesoderm in response to a number of signaling molecules produced by neighboring tissues such as neural tube, notochord and dorsal ectoderm. Candidate molecules for this complex signaling activity include Sonic hedgehog, Wnts and Noggin as positive activators and BMP4 as a possible inhibitor. Recently, the receptors and the post-receptor pathways for Sonic hedgehog and Wnts have been characterized, and this has opened up the possibility of linking these signaling events to the activation of myogenic regulatory factor genes such as Myf5 and MyoD and functionally related genes such as Pax3. Here we focus on the role of Wnts, their putative receptors Frizzled and the soluble antagonist Frzb1 in regulating mammalian myogenesis. Although it is becoming evident that the signaling downstream of Frizzled receptors is much more complex than anticipated, it is conceivable that it may lead to transcriptional activation of Myf5 and MyoD and to initiation of myogenesis. However, the fact that both Wnts and Sonic hedgehog have a strong effect on cell proliferation and survival suggests that they may contribute to the overall process of myogenesis by a combination of these different biological activities.
Topics: Animals; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; DNA-Binding Proteins; Hedgehog Proteins; Mammals; Mesoderm; Muscle Proteins; Muscle, Skeletal; MyoD Protein; Myogenic Regulatory Factor 5; Proteins; Proto-Oncogene Proteins; Trans-Activators; Wnt Proteins; Zebrafish Proteins
PubMed: 10601008
DOI: 10.1093/emboj/18.24.6867 -
Developmental Dynamics : An Official... Sep 2007Somitic and head mesoderm contribute to cartilage and bone and deliver the entire skeletal musculature. Studies on avian somite patterning and cell differentiation led... (Review)
Review
Somitic and head mesoderm contribute to cartilage and bone and deliver the entire skeletal musculature. Studies on avian somite patterning and cell differentiation led to the view that these processes depend solely on cues from surrounding tissues. However, evidence is accumulating that some developmental decisions depend on information within the somitic tissue itself. Moreover, recent studies established that head and somitic mesoderm, though delivering the same tissue types, are set up to follow their own, distinct developmental programmes. With a particular focus on the chicken embryo, we review the current understanding of how extrinsic signalling, operating in a framework of intrinsically regulated constraints, controls paraxial mesoderm patterning and cell differentiation.
Topics: Amnion; Animals; Body Patterning; Cell Differentiation; Cell Lineage; Chick Embryo; Developmental Biology; Gene Expression Regulation, Developmental; Mesoderm; Models, Anatomic; Models, Biological; Somites
PubMed: 17654605
DOI: 10.1002/dvdy.21241 -
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 -
Journal of Anatomy Oct 2019Somites are epithelial segments of the paraxial mesoderm. Shortly after their formation, the epithelial somites undergo extensive cellular rearrangements and form...
Somites are epithelial segments of the paraxial mesoderm. Shortly after their formation, the epithelial somites undergo extensive cellular rearrangements and form specific somite compartments, including the sclerotome and the myotome, which give rise to the axial skeleton and to striated musculature, respectively. The dynamics of somite development varies along the body axis, but most research has focused on somite development at thoracolumbar levels. The development of tail somites has not yet been thoroughly characterized, even though vertebrate tail development has been intensely studied recently with respect to the termination of segmentation and the limitation of body length in evolution. Here, we provide a detailed description of the somites in the avian tail from the beginning of tail formation at HH-stage 20 to the onset of degeneration of tail segments at HH-stage 27. We characterize the formation of somite compartment formation in the tail region with respect to morphology and the expression patterns of the sclerotomal marker gene paired-box gene 1 (Pax1) and the myotomal marker genes MyoD and myogenic factor 5 (Myf5). Our study gives insight into the development of the very last segments formed in the avian embryo, and provides a basis for further research on the development of tail somite derivatives such as tail vertebrae, pygostyle and tail musculature.
Topics: Animals; Birds; Chick Embryo; Embryonic Development; Somites; Tail
PubMed: 31225912
DOI: 10.1111/joa.13032 -
Hepatology Communications Mar 2021The hepatic mesenchyme has been studied extensively in the context of liver fibrosis; however, much less is known regarding the role of mesenchymal cells during liver... (Review)
Review
The hepatic mesenchyme has been studied extensively in the context of liver fibrosis; however, much less is known regarding the role of mesenchymal cells during liver regeneration. As our knowledge of the cellular and molecular mechanisms driving hepatic regeneration deepens, the key role of the mesenchymal compartment during the regenerative response has been increasingly appreciated. Single-cell genomics approaches have recently uncovered both spatial and functional zonation of the hepatic mesenchyme in homeostasis and following liver injury. Here we discuss how the use of preclinical models, from in vivo mouse models to organoid-based systems, are helping to shape our understanding of the role of the mesenchyme during liver regeneration, and how these approaches should facilitate the precise identification of highly targeted, pro-regenerative therapies for patients with liver disease.
Topics: Animals; Cells, Cultured; Hepatic Stellate Cells; Humans; Liver; Liver Diseases; Liver Regeneration; Mesoderm; Mice
PubMed: 33681672
DOI: 10.1002/hep4.1628 -
Annual Review of Physiology 2011The mesenchymal elements of the intestinal lamina propria reviewed here are the myofibroblasts, fibroblasts, mural cells (pericytes) of the vasculature, bone... (Review)
Review
The mesenchymal elements of the intestinal lamina propria reviewed here are the myofibroblasts, fibroblasts, mural cells (pericytes) of the vasculature, bone marrow-derived stromal stem cells, smooth muscle of the muscularis mucosae, and smooth muscle surrounding the lymphatic lacteals. These cells share similar marker molecules, origins, and coordinated biological functions previously ascribed solely to subepithelial myofibroblasts. We review the functional anatomy of intestinal mesenchymal cells and describe what is known about their origin in the embryo and their replacement in adults. As part of their putative role in intestinal mucosal morphogenesis, we consider the intestinal stem cell niche. Lastly, we review emerging information about myofibroblasts as nonprofessional immune cells that may be important as an alarm system for the gut and as a participant in peripheral immune tolerance.
Topics: Animals; Biomarkers; Cell Differentiation; Epithelial-Mesenchymal Transition; Female; Hedgehog Proteins; Humans; Immunity, Innate; Intestines; Male; Mesenchymal Stem Cells; Mesoderm; Mice; Mucous Membrane; Myofibroblasts; Pericytes; Signal Transduction; Stromal Cells
PubMed: 21054163
DOI: 10.1146/annurev.physiol.70.113006.100646 -
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 -
Biology Open Sep 2022Recent genetic lineage tracing studies reveal heterogeneous origins of vascular endothelial cells and pericytes in the developing brain vasculature, despite classical...
Recent genetic lineage tracing studies reveal heterogeneous origins of vascular endothelial cells and pericytes in the developing brain vasculature, despite classical experimental evidence for a mesodermal origin. Here we provide evidence through a genetic lineage tracing experiment that cephalic paraxial mesodermal cells give rise to endothelial cells and pericytes in the developing mouse brain. We show that Hepatic leukemia factor (Hlf) is transiently expressed by cephalic paraxial mesenchyme at embryonic day (E) 8.0-9.0 and the genetically marked E8.0 Hlf-expressing cells mainly contribute to the developing brain vasculature. Interestingly, the genetically marked E10.5 Hlf-expressing cells, which have been previously reported to contain embryonic hematopoietic stem cells, fail to contribute to the vascular cells. Combined, our genetic lineage tracing data demonstrate that a transient expression of Hlf marks a cephalic paraxial mesenchyme contributing to the developing brain vasculature. This article has an associated First Person interview with the first author of the paper.
Topics: Animals; Brain; Endothelial Cells; Humans; Leukemia; Mesoderm; Mice; Stem Cells
PubMed: 36017733
DOI: 10.1242/bio.059510 -
Developmental Biology Mar 2018The murine pancreas buds from the ventral embryonic endoderm at approximately 8.75 dpc and a second pancreas bud emerges from the dorsal endoderm by 9.0 dpc. Although it...
The murine pancreas buds from the ventral embryonic endoderm at approximately 8.75 dpc and a second pancreas bud emerges from the dorsal endoderm by 9.0 dpc. Although it is clear that secreted signals from adjacent mesoderm-derived sources are required for both the appropriate emergence and further refinement of the pancreatic endoderm, neither the exact signals nor the requisite tissue sources have been defined in mammalian systems. Herein we use DiI fate mapping of cultured murine embryos to identify the embryonic sources of both the early inductive and later condensed pancreatic mesenchyme. Despite being capable of supporting pancreas induction from dorsal endoderm in co-culture experiments, we find that in the context of the developing embryo, the dorsal aortae as well as the paraxial, intermediate, and lateral mesoderm derivatives only transiently associate with the dorsal pancreas bud, producing descendants that are decidedly anterior to the pancreas bud. Unlike these other mesoderm derivatives, the axial (notochord) descendants maintain association with the dorsal pre-pancreatic endoderm and early pancreas bud. This fate mapping data points to the notochord as the likely inductive source in vivo while also revealing dynamic morphogenetic movements displayed by individual mesodermal subtypes. Because none of the mesoderm examined above produced the pancreatic mesenchyme that condenses around the induced bud to support exocrine and endocrine differentiation, we also sought to identify the mesodermal origins of this mesenchyme. We identify a portion of the coelomic mesoderm that contributes to the condensed pancreatic mesenchyme. In conclusion, we identify a portion of the notochord as a likely source of the signals required to induce and maintain the early dorsal pancreas bud, demonstrate that the coelomic mesothelium contributes to the dorsal and ventral pancreatic mesenchyme, and provide insight into the dynamic morphological rearrangements of mesoderm-derived tissues during early organogenesis stages of mammalian development.
Topics: Animals; Embryo, Mammalian; Mesoderm; Mice; Organogenesis; Pancreas
PubMed: 29329912
DOI: 10.1016/j.ydbio.2018.01.003