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Experimental & Molecular Medicine Aug 2020Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order... (Review)
Review
Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order to model this development with PSCs, and for the application of PSCs in clinical settings. Skeletal tissues originate from three types of cell populations: the paraxial mesoderm, lateral plate mesoderm, and neural crest. The paraxial mesoderm gives rise to the sclerotome mainly through somitogenesis. In this process, key developmental processes, including initiation of the segmentation clock, formation of the determination front, and the mesenchymal-epithelial transition, are sequentially coordinated. The sclerotome further forms vertebral columns and contributes to various other tissues, such as tendons, vessels (including the dorsal aorta), and even meninges. To understand the molecular mechanisms underlying these developmental processes, extensive studies have been conducted. These studies have demonstrated that a gradient of activities involving multiple signaling pathways specify the embryonic axis and induce cell-type-specific master transcription factors in a spatiotemporal manner. Moreover, applying the knowledge of mesoderm development, researchers have attempted to recapitulate the in vivo development processes in in vitro settings, using mouse and human PSCs. In this review, we summarize the state-of-the-art understanding of mesoderm development and in vitro modeling of mesoderm development using PSCs. We also discuss future perspectives on the use of PSCs to generate skeletal tissues for basic research and clinical applications.
Topics: Animals; Bone Development; Bone and Bones; Humans; Mesoderm; Pluripotent Stem Cells; Somites; Wound Healing
PubMed: 32788657
DOI: 10.1038/s12276-020-0482-1 -
Development (Cambridge, England) Jun 2020The lateral plate mesoderm (LPM) forms the progenitor cells that constitute the heart and cardiovascular system, blood, kidneys, smooth muscle lineage and limb skeleton... (Review)
Review
The lateral plate mesoderm (LPM) forms the progenitor cells that constitute the heart and cardiovascular system, blood, kidneys, smooth muscle lineage and limb skeleton in the developing vertebrate embryo. Despite this central role in development and evolution, the LPM remains challenging to study and to delineate, owing to its lineage complexity and lack of a concise genetic definition. Here, we outline the processes that govern LPM specification, organization, its cell fates and the inferred evolutionary trajectories of LPM-derived tissues. Finally, we discuss the development of seemingly disparate organ systems that share a common LPM origin.
Topics: Animals; Cardiovascular System; Cell Differentiation; Cell Lineage; Embryonic Development; Gene Expression Regulation, Developmental; Humans; Mesoderm; Stem Cells; Transcription Factors
PubMed: 32561665
DOI: 10.1242/dev.175059 -
ELife Jun 2022Advanced imaging techniques reveal details of the interactions between the two layers of the embryonic midgut that influence its ultimate shape.
Advanced imaging techniques reveal details of the interactions between the two layers of the embryonic midgut that influence its ultimate shape.
Topics: Animals; Drosophila; Endoderm; Gene Expression Regulation, Developmental; Mesoderm; Morphogenesis
PubMed: 35771125
DOI: 10.7554/eLife.80416 -
Seminars in Cell & Developmental Biology Jul 2022The discovery of mesoderm inducing signals helped usher in the era of molecular developmental biology, and today the mechanisms of mesoderm induction and patterning are... (Review)
Review
The discovery of mesoderm inducing signals helped usher in the era of molecular developmental biology, and today the mechanisms of mesoderm induction and patterning are still intensely studied. Mesoderm induction begins during gastrulation, but recent evidence in vertebrates shows that this process continues after gastrulation in a group of posteriorly localized cells called neuromesodermal progenitors (NMPs). NMPs reside within the post-gastrulation embryonic structure called the tailbud, where they make a lineage decision between ectoderm (spinal cord) and mesoderm. The majority of NMP-derived mesoderm generates somites, but also contributes to lateral mesoderm fates such as endothelium. The discovery of NMPs provides a new paradigm in which to study vertebrate mesoderm induction. This review will discuss mechanisms of mesoderm induction within NMPs, and how they have informed our understanding of mesoderm induction more broadly within vertebrates as well as animal species outside of the vertebrate lineage. Special focus will be given to the signaling networks underlying NMP-derived mesoderm induction and patterning, as well as emerging work on the significance of partial epithelial-mesenchymal states in coordinating cell fate and morphogenesis.
Topics: Animals; Body Patterning; Cell Differentiation; Gastrulation; Gene Expression Regulation, Developmental; Mesoderm; Somites
PubMed: 34840081
DOI: 10.1016/j.semcdb.2021.11.010 -
Anatomical Record (Hoboken, N.J. : 2007) Aug 2022The process by which upper respiratory tract structures have changed over deep evolutionary time is, in part, reflected in the process of embryologic development. The...
The process by which upper respiratory tract structures have changed over deep evolutionary time is, in part, reflected in the process of embryologic development. The nasopharynx in particular is a centrally located space bounded by components of the respiratory portion of the nasal cavity, cranial base, soft palate, and Eustachian tube. The development of these components can be understood both in terms of embryologic structures such as the branchial arches and paraxial mesoderm and through fossil evidence dating as far back as the earliest agnathan fish of the Cambrian Period. Understanding both the evolution and development of these structures has been an immeasurable benefit to the otolaryngologist seeking to model disease etiology of both common and rare conditions. This discussion is a primer for those who may be unfamiliar with the central importance of the nasopharynx both in terms of our evolutionary history and early embryological development of vital cranial and upper respiratory tract structures.
Topics: Animals; Biological Evolution; Branchial Region; Developmental Biology; Mesoderm; Nasopharynx; Skull
PubMed: 35665451
DOI: 10.1002/ar.24950 -
The International Journal of... 2018Somites are epithelial blocks of paraxial mesoderm that define the vertebrate embryonic segments. They are responsible for imposing the metameric pattern observed in... (Review)
Review
Somites are epithelial blocks of paraxial mesoderm that define the vertebrate embryonic segments. They are responsible for imposing the metameric pattern observed in many tissues of the adult such as the vertebrae, and they give rise to most of the axial skeleton and skeletal muscles of the trunk. Due to its easy accessibility in the egg, the chicken embryo has provided an ideal model to study somite development. Somites were first described in the chicken embryo by Malpighi in the 17 century, soon after the invention of the microscope. Most of the major concepts relating to somite segmentation and differentiation result from studies performed in the chicken embryo (Brand-Saberi and Christ, 2000). In this review, we will discuss how studies on somites in avian embryos have contributed to our understanding of key developmental processes such as segmentation, control of bilateral symmetry or axis regionalization.
Topics: Animals; Body Patterning; Cell Differentiation; Cell Lineage; Chick Embryo; Chickens; Embryology; Embryonic Development; Gene Expression Regulation, Developmental; History, 17th Century; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Mesoderm; Mice; Somites; Vertebrates; Zebrafish
PubMed: 29616740
DOI: 10.1387/ijdb.180036op -
The International Journal of... 2017The vertebrate head characteristically exhibits a complex pattern with sense organs, brain, paired eyes and jaw muscles, and the brain case is not found in other... (Review)
Review
The vertebrate head characteristically exhibits a complex pattern with sense organs, brain, paired eyes and jaw muscles, and the brain case is not found in other chordates. How the extant vertebrate head has evolved remains enigmatic. Historically, there have been two conflicting views on the origin of the vertebrate head, segmental and non-segmental views. According to the segmentalists, the vertebrate head is organized as a metameric structure composed of segments equivalent to those in the trunk; a metamere in the vertebrate head was assumed to consist of a somite, a branchial arch and a set of cranial nerves, considering that the head evolved from rostral segments of amphioxus-like ancestral vertebrates. Non-segmentalists, however, considered that the vertebrate head was not segmental. In that case, the ancestral state of the vertebrate head may be non-segmented, and rostral segments in amphioxus might have been secondarily gained, or extant vertebrates might have evolved through radical modifications of amphioxus-like ancestral vertebrate head. Comparative studies of mesodermal development in amphioxus and vertebrate gastrula embryos have revealed that mesodermal gene expressions become segregated into two domains anteroposteriorly to specify the head mesoderm and trunk mesoderm only in vertebrates; in this segregation, key genes such as delta and hairy, involved in segment formation, are expressed in the trunk mesoderm, but not in the head mesoderm, strongly suggesting that the head mesoderm of extant vertebrates is not segmented. Taken together, the above finding possibly adds a new insight into the origin of the vertebrate head; the vertebrate head mesoderm would have evolved through an anteroposterior polarization of the paraxial mesoderm if the ancestral vertebrate had been amphioxus-like.
Topics: Animals; Body Patterning; Cephalochordata; Gene Expression Regulation, Developmental; Head; Lancelets; Models, Biological; Somites; Vertebrates
PubMed: 29319111
DOI: 10.1387/ijdb.170121to -
The Journal of Biological Chemistry Jun 2017Critical steps in the specification of embryonic cell lineages occur after implantation, but gaining insight into the molecular details of these cellular processes has... (Review)
Review
Critical steps in the specification of embryonic cell lineages occur after implantation, but gaining insight into the molecular details of these cellular processes has been challenging. Jin and co-workers now report the transcriptomic signatures and molecular heterogeneity of more than 600 single cells from mouse embryos at days 5.5 and 6.5, advancing our understanding of how early embryonic cells make cell-fate decisions into mesoderm and endoderm lineages.
Topics: Animals; Cell Lineage; Embryo, Mammalian; Endoderm; Mesoderm; Mice
PubMed: 28600307
DOI: 10.1074/jbc.H117.780585 -
Developmental Dynamics : An Official... Sep 2007Somites are segments of paraxial mesoderm that give rise to a multitude of tissues in the vertebrate embryo. Many decades of intensive research have provided a wealth of... (Review)
Review
Somites are segments of paraxial mesoderm that give rise to a multitude of tissues in the vertebrate embryo. Many decades of intensive research have provided a wealth of data on the complex molecular interactions leading to the formation of various somitic derivatives. In this review, we focus on the crucial role of the somites in building the body wall and limbs of amniote embryos. We give an overview on the current knowledge on the specification and differentiation of somitic cell lineages leading to the development of the vertebral column, skeletal muscle, connective tissue, meninges, and vessel endothelium, and highlight the importance of the somites in establishing the metameric pattern of the vertebrate body.
Topics: Amnion; Animals; Cell Differentiation; Cell Lineage; Chick Embryo; Embryonic Development; Endothelium; Epithelium; Extremities; Microscopy, Electron, Scanning; Models, Anatomic; Models, Biological; Muscles; Somites; Spinal Cord
PubMed: 17557304
DOI: 10.1002/dvdy.21189 -
International Journal of Molecular... Aug 2021To ensure the formation of a properly patterned embryo, multiple processes must operate harmoniously at sequential phases of development. This is implemented by mutual... (Review)
Review
To ensure the formation of a properly patterned embryo, multiple processes must operate harmoniously at sequential phases of development. This is implemented by mutual interactions between cells and tissues that together regulate the segregation and specification of cells, their growth and morphogenesis. The formation of the spinal cord and paraxial mesoderm derivatives exquisitely illustrate these processes. Following early gastrulation, while the vertebrate body elongates, a population of bipotent neuromesodermal progenitors resident in the posterior region of the embryo generate both neural and mesodermal lineages. At later stages, the somitic mesoderm regulates aspects of neural patterning and differentiation of both central and peripheral neural progenitors. Reciprocally, neural precursors influence the paraxial mesoderm to regulate somite-derived myogenesis and additional processes by distinct mechanisms. Central to this crosstalk is the activity of the axial notochord, which, via sonic hedgehog signaling, plays pivotal roles in neural, skeletal muscle and cartilage ontogeny. Here, we discuss the cellular and molecular basis underlying this complex developmental plan, with a focus on the logic of sonic hedgehog activities in the coordination of the neural-mesodermal axis.
Topics: Animals; Cell Differentiation; Embryonic Stem Cells; Gene Expression Regulation, Developmental; Hedgehog Proteins; Humans; Mesoderm; Neural Tube
PubMed: 34502050
DOI: 10.3390/ijms22179141