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Piatkowska AM, Adhikari K, Moverley AA, Turmaine M, Glazier JA, Plachta N, Evans SE, Stern CD. Sequential changes in cellular properties accompanying amniote somite formation. J Anat 2022; 242:417-435. [PMID: 36423208 PMCID: PMC9919497 DOI: 10.1111/joa.13791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/30/2022] [Accepted: 10/28/2022] [Indexed: 11/26/2022] Open
Abstract
Somites are transient structures derived from the pre-somitic mesoderm (PSM), involving mesenchyme-to-epithelial transition (MET) where the cells change their shape and polarize. Using Scanning electron microscopy (SEM), immunocytochemistry and confocal microscopy, we study the progression of these events along the tail-to-head axis of the embryo, which mirrors the progression of somitogenesis (younger cells located more caudally). SEM revealed that PSM epithelialization is a gradual process, which begins much earlier than previously thought, starting with the dorsalmost cells, then the medial ones, and then, simultaneously, the ventral and lateral cells, before a somite fully separates from the PSM. The core (internal) cells of the PSM and somites never epithelialize, which suggests that the core cells could be 'trapped' within the somitocoele after cells at the surfaces of the PSM undergo MET. Three-dimensional imaging of the distribution of the cell polarity markers PKCζ, PAR3, ZO1, the Golgi marker GM130 and the apical marker N-cadherin reveal that the pattern of polarization is distinctive for each marker and for each surface of the PSM, but the order of these events is not the same as the progression of cell elongation. These observations challenge some assumptions underlying existing models of somite formation.
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Affiliation(s)
- Agnieszka M. Piatkowska
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Kaustubh Adhikari
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK,Present address:
The Open UniversityMilton KeynesUK
| | - Adam A. Moverley
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Mark Turmaine
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - James A. Glazier
- Department of Intelligent Systems EngineeringBiocomplexity InstituteBloomingtonIndianaUSA
| | - Nicolas Plachta
- Department of Cell and Developmental Biology, 9‐123 Smilow Center for Translational Research, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Susan E. Evans
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Claudio D. Stern
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
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2
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Clayton SW, Angermeier A, Halbrooks JE, McCardell R, Serra R. TGFβ signaling is required for sclerotome resegmentation during development of the spinal column in Gallus gallus. Dev Biol 2022; 488:120-130. [PMID: 35644252 PMCID: PMC9552462 DOI: 10.1016/j.ydbio.2022.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 05/02/2022] [Accepted: 05/19/2022] [Indexed: 12/14/2022]
Abstract
We previously showed the importance of TGFβ signaling in development of the mouse axial skeleton. Here, we provide the first direct evidence that TGFβ signaling is required for resegmentation of the sclerotome using chick embryos. Lipophilic fluorescent tracers, DiO and DiD, were microinjected into adjacent somites of embryos treated with or without TGFβRI inhibitors, SB431542, SB525334 or SD208, at developmental day E2.5 (HH16). Lineage tracing of labeled cells was observed over the course of 4 days until the completion of resegmentation at E6.5 (HH32). Vertebrae were malformed and intervertebral discs were small and misshapen in inhibitor injected embryos. Hypaxial myofibers were also increased in thickness after treatment with the inhibitor. Inhibition of TGFβ signaling resulted in alterations in resegmentation that ranged between full, partial, and slanted shifts in distribution of DiO or DiD labeled cells within vertebrae. Patterning of rostro-caudal markers within sclerotome was disrupted at E3.5 after treatment with TGFβRI inhibitor with rostral domains expressing both rostral and caudal markers. We propose that TGFβ signaling regulates rostro-caudal polarity and subsequent resegmentation in sclerotome during spinal column development.
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Affiliation(s)
- Sade W Clayton
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, AL, USA; Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Allyson Angermeier
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, AL, USA
| | - Jacob E Halbrooks
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, AL, USA
| | - Ronisha McCardell
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, AL, USA; Dillard University, Greensburg, LA, USA
| | - Rosa Serra
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, AL, USA.
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3
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Wegler M, Roth C, Schumann E, Kogan J, Totten E, Guillen Sacoto MJ, Abou Jamra R, Hornemann F. Congenital cervical spine malformation due to bi-allelic RIPPLY2 variants in spondylocostal dysostosis type 6. Clin Genet 2021; 99:565-571. [PMID: 33410135 DOI: 10.1111/cge.13916] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/30/2020] [Accepted: 01/02/2021] [Indexed: 01/14/2023]
Abstract
RIPPLY2 is an essential part of the formation of somite patterning during embryogenesis and in establishment of rostro-caudal polarity. Here, we describe three individuals from two families with compound-heterozygous variants in RIPPLY2 (NM_001009994.2): c.238A > T, p.(Arg80*) and c.240-4 T > G, p.(?), in two 15 and 20-year-old sisters, and a homozygous nonsense variant, c.238A > T, p.(Arg80*), in an 8 year old boy. All patients had multiple vertebral body malformations in the cervical and thoracic region, small or absent rib involvement, myelopathies, and common clinical features of SCDO6 including scoliosis, mild facial asymmetry, spinal spasticity and hemivertebrae. The nonsense variant can be classified as likely pathogenic based on the ACMG criteria while the splice variants must be classified as a variant of unknown significance. With this report on two further families, we confirm RIPPLY2 as the gene for SCDO6 and broaden the phenotype by adding myelopathy with or without spinal canal stenosis and spinal spasticity to the symptom spectrum.
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Affiliation(s)
- Meret Wegler
- Department of Human Genetics, University of Leipzig, Leipzig, Saxony, Germany
| | - Christian Roth
- Division of Pediatric Radiology, University Hospital Leipzig, Leipzig, Saxony, Germany
| | - Eckehard Schumann
- Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Saxony, Germany
| | - Jillene Kogan
- Centre of Medical Genetics, Advocate Medical Group, Park Ridge, Illinois, USA
| | - Ellen Totten
- Centre of Medical Genetics, Advocate Medical Group, Park Ridge, Illinois, USA
| | | | - Rami Abou Jamra
- Department of Human Genetics, University of Leipzig, Leipzig, Saxony, Germany
| | - Frauke Hornemann
- Department of Pediatric Neurology, University Hospital for Children and Adolescents, Leipzig, Saxony, Germany
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4
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Tessier S, Risbud MV. Understanding embryonic development for cell-based therapies of intervertebral disc degeneration: Toward an effort to treat disc degeneration subphenotypes. Dev Dyn 2020; 250:302-317. [PMID: 32564440 DOI: 10.1002/dvdy.217] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 12/19/2022] Open
Abstract
Chronic low back and neck pain are associated with intervertebral disc degeneration and are major contributors to the global burden of disability. New evidence now suggests that disc degeneration comprises a spectrum of subphenotypes influenced by genetic background, age, and environmental factors, which may be contributing to the mixed outcomes seen in clinical trials of cell-based therapies that aim to treat disc degeneration. This problem is further compounded by the fact that disc degeneration and aging coincide with an exhaustion of endogenous progenitor cells, imposing limitations on the regenerative capacity of the disc. At the bench-side, current work is focused on applying our knowledge of embryonic disc development to direct and refine differentiation of adult and human-induced pluripotent stem cells into notochord-like and nucleus pulposus-like cells for use in novel cell-based therapies. Accordingly, this review presents the salient features of intervertebral disc development, post-natal maintenance, and regeneration, with emphasis on recent advancements. We also discuss how a stratified approach can be undertaken for the development of future cell-based therapies to bring emerging subphenotypes into consideration.
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Affiliation(s)
- Steven Tessier
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA.,Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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5
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Characterization of paralogous uncx transcription factor encoding genes in zebrafish. Gene X 2019; 721S:100011. [PMID: 31193955 PMCID: PMC6543554 DOI: 10.1016/j.gene.2019.100011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/23/2022] Open
Abstract
The paired-type homeodomain transcription factor Uncx is involved in multiple processes of embryogenesis in vertebrates. Reasoning that zebrafish genes uncx4.1 and uncx are orthologs of mouse Uncx, we studied their genomic environment and developmental expression. Evolutionary analyses indicate the zebrafish uncx genes as being paralogs deriving from teleost-specific whole-genome duplication. Whole-mount in situ mRNA hybridization of uncx transcripts in zebrafish embryos reveals novel expression domains, confirms those previously known, and suggests sub-functionalization of paralogs. Using genetic mutants and pharmacological inhibitors, we investigate the role of signaling pathways on the expression of zebrafish uncx genes in developing somites. In identifying putative functional role(s) of zebrafish uncx genes, we hypothesized that they encode transcription factors that coordinate growth and innervation of somitic muscles. The Uncx4.1 and Uncx genes derive from the teleost-specific whole-genome duplication. Uncx genes are expressed during embryogenesis in unique and overlapping domains. Uncx gene expression during somite differentiation is regulated by FGF signaling. Synteny and expression profiles correlate Uncx genes with axon guidance.
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Key Words
- AP, antero-posterior
- Ace, acerebellar
- CAMP, conserved ancestral microsyntenic pairs
- CNE, conserved non-coding elements
- CRM, cis-regulatory module
- CS, Corpuscle of Stannius
- CaP, caudal primary motor neuron axons
- Ce, cerebellum
- Development
- Di, diencephalon
- Elfn1, Extracellular Leucine Rich Repeat And Fibronectin Type III Domain Containing 1
- Ey, eye
- FB, forebrain
- FGF, fibroblast growth factor
- Flh, floating head
- HB, hindbrain
- HM, hybridization mix
- Hy, hypothalamus
- MO, morpholino
- Mical, molecule interacting with CasL
- No, notochord
- OP, olfactory placode
- OT, optic tectum
- PA, pharyngeal arches
- PSM, presomitic mesoderm
- SC, spinal cord
- Shh, sonic hedgehog
- Signaling pathway
- So, somites
- Synteny
- TSGD
- TSGD, teleost-specific genome duplication
- Te, telencephalon
- Th, thalamus
- Uncx
- VLP, ventro-lateral-posterior
- WIHC, whole-mount immunohistochemistry
- WISH, whole-mount in situ hybridization
- YE, yolk extension
- Yo, yolk
- Zebrafish
- cyc, cyclops
- fss, fused-somites
- hpf, hours post fertilization
- ptc, patched
- smu, slow-muscle-omitted
- syu, sonic-you
- yot, you-too
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6
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Wang F, Zhang C, Sinkemani A, Shi R, Xie ZY, Chen L, Mao L, Wu XT. A histocytological and radiological overview of the natural history of intervertebral disk: from embryonic formation to age-related degeneration. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2019; 28:633-648. [PMID: 30715648 DOI: 10.1007/s00586-019-05903-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 01/05/2019] [Accepted: 01/25/2019] [Indexed: 12/24/2022]
Abstract
PURPOSE To elucidate the natural history of intervertebral disk (IVD) and characterize its embryonic beginnings and age-related degeneration. METHODS Coronal sections of embryonic (E13.5-neonatal) and postnatal (4-60-week-old) Sprague-Dawley rat IVD were stained by a series of histological stainings (hematoxylin and eosin, Alcian blue, Picrosirius red, Masson, Periodic acid-Schiff). Growth kinetics within embryonic IVD were evaluated by immunohistochemical staining of Ki67 and proliferating cell nuclear antigen. Postnatal maturation and degeneration of IVD were visualized on radiology by X-ray, CT, and MR imaging. RESULTS During the formation of rat IVD, inner annulus fibrosus (AF) and cartilaginous endplate (CEP) shared similar cell density, extracellular matrix, and potential of growth kinetics; notochord provided increased and enlarged cytoplasmic vacuoles to generate nucleus pulposus (NP), part of which was retained within CEP. Postnatally, vacuolated notochord cells were reduced by devacuolation, while chondrocytic NP cells increased; cartilaginous layers of CEP were narrowed by vertebrae growth and secondary ossification; fibrotic portion of AF decreased as cartilaginous matrix accumulated and infiltrated outward. In aged and degenerated IVD, large longitudinal fissures were detected near the boundaries between inner and outer AF, whereas both reduced cellularity and accumulated cell clusters were evident within the dehydrated NP; only part of these histocytological changes could be reported on radiology. CONCLUSIONS By showing that the natural history of IVD is orchestrated by a dynamic histocytological regulation, our study may facilitate better understanding of the developmental defects, cellular heterogeneity, age-related degenerative mechanisms, and biological regeneration of IVD. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Feng Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Cong Zhang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Arjun Sinkemani
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Rui Shi
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Zhi-Yang Xie
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Lu Chen
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Lu Mao
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Xiao-Tao Wu
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China. .,Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.
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7
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Ward L, Pang ASW, Evans SE, Stern CD. The role of the notochord in amniote vertebral column segmentation. Dev Biol 2018; 439:3-18. [PMID: 29654746 PMCID: PMC5971204 DOI: 10.1016/j.ydbio.2018.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 11/22/2022]
Abstract
The vertebral column is segmented, comprising an alternating series of vertebrae and intervertebral discs along the head-tail axis. The vertebrae and outer portion (annulus fibrosus) of the disc are derived from the sclerotome part of the somites, whereas the inner nucleus pulposus of the disc is derived from the notochord. Here we investigate the role of the notochord in vertebral patterning through a series of microsurgical experiments in chick embryos. Ablation of the notochord causes loss of segmentation of vertebral bodies and discs. However, the notochord cannot segment in the absence of the surrounding sclerotome. To test whether the notochord dictates sclerotome segmentation, we grafted an ectopic notochord. We find that the intrinsic segmentation of the sclerotome is dominant over any segmental information the notochord may possess, and no evidence that the chick notochord is intrinsically segmented. We propose that the segmental pattern of vertebral bodies and discs in chick is dictated by the sclerotome, which first signals to the notochord to ensure that the nucleus pulposus develops in register with the somite-derived annulus fibrosus. Later, the notochord is required for maintenance of sclerotome segmentation as the mature vertebral bodies and intervertebral discs form. These results highlight differences in vertebral development between amniotes and teleosts including zebrafish, where the notochord dictates the segmental pattern. The relative importance of the sclerotome and notochord in vertebral patterning has changed significantly during evolution. The chick notochord has no intrinsic segmentation. Neither notochord or sclerotome can segment normally without the other. The notochord attracts sclerotome cells to the midline. Vertebral segmentation involves reciprocal signals between notochord and sclerotome.
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Affiliation(s)
- Lizzy Ward
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, U.K
| | - Angel S W Pang
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, U.K
| | - Susan E Evans
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, U.K
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, U.K..
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8
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Abstract
A prominent anatomical feature of the peripheral nervous system is the segmentation of mixed (motor, sensory and autonomic) spinal nerves alongside the spinal cord. During early development their axon growth cones avoid the developing vertebral elements by traversing the anterior/cranial half of each somite-derived sclerotome, so ensuring the separation of spinal nerves from vertebral bones as axons extend towards their peripheral targets. A glycoprotein expressed on the surface of posterior half-sclerotome cells confines growth cones to the anterior half-sclerotomes by contact repulsion. A closely similar glycoprotein is expressed in avian and mammalian grey matter, where we hypothesize it may have evolved to regulate neural plasticity in birds and mammals.
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Affiliation(s)
- Roger Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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9
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Siebel C, Lendahl U. Notch Signaling in Development, Tissue Homeostasis, and Disease. Physiol Rev 2017; 97:1235-1294. [PMID: 28794168 DOI: 10.1152/physrev.00005.2017] [Citation(s) in RCA: 583] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.
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Affiliation(s)
- Chris Siebel
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Urban Lendahl
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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10
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Lawson LY, Harfe BD. Developmental mechanisms of intervertebral disc and vertebral column formation. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [DOI: 10.1002/wdev.283] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 05/09/2017] [Accepted: 05/23/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Lisa Y. Lawson
- Department of Molecular Genetics and Microbiology; Genetics Institute University of Florida, College of Medicine; Gainesville FL USA
| | - Brian D. Harfe
- Department of Molecular Genetics and Microbiology; Genetics Institute University of Florida, College of Medicine; Gainesville FL USA
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11
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Mekonen HK, Hikspoors JPJM, Mommen G, Kruepunga N, Köhler SE, Lamers WH. Closure of the vertebral canal in human embryos and fetuses. J Anat 2017; 231:260-274. [PMID: 28585249 DOI: 10.1111/joa.12638] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2017] [Indexed: 11/28/2022] Open
Abstract
The vertebral column is the paradigm of the metameric architecture of the vertebrate body. Because the number of somites is a convenient parameter to stage early human embryos, we explored whether the closure of the vertebral canal could be used similarly for staging embryos between 7 and 10 weeks of development. Human embryos (5-10 weeks of development) were visualized using Amira 3D® reconstruction and Cinema 4D® remodelling software. Vertebral bodies were identifiable as loose mesenchymal structures between the dense mesenchymal intervertebral discs up to 6 weeks and then differentiated into cartilaginous structures in the 7th week. In this week, the dense mesenchymal neural processes also differentiated into cartilaginous structures. Transverse processes became identifiable at 6 weeks. The growth rate of all vertebral bodies was exponential and similar between 6 and 10 weeks, whereas the intervertebral discs hardly increased in size between 6 and 8 weeks and then followed vertebral growth between 8 and 10 weeks. The neural processes extended dorsolaterally (6th week), dorsally (7th week) and finally dorsomedially (8th and 9th weeks) to fuse at the midthoracic level at 9 weeks. From there, fusion extended cranially and caudally in the 10th week. Closure of the foramen magnum required the development of the supraoccipital bone as a craniomedial extension of the exoccipitals (neural processes of occipital vertebra 4), whereas a growth burst of sacral vertebra 1 delayed closure until 15 weeks. Both the cranial- and caudal-most vertebral bodies fused to form the basioccipital (occipital vertebrae 1-4) and sacrum (sacral vertebrae 1-5). In the sacrum, fusion of its so-called alar processes preceded that of the bodies by at least 6 weeks. In conclusion, the highly ordered and substantial changes in shape of the vertebral bodies leading to the formation of the vertebral canal make the development of the spine an excellent, continuous staging system for the (human) embryo between 6 and 10 weeks of development.
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Affiliation(s)
- Hayelom K Mekonen
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands
| | - Jill P J M Hikspoors
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands
| | - Greet Mommen
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands
| | - Nutmethee Kruepunga
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands
| | - S Eleonore Köhler
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands
| | - Wouter H Lamers
- Department of Anatomy & Embryology, Maastricht University, Maastricht, The Netherlands.,Tytgat Institute for Liver and Intestinal Research, Academic Medical Centre, Amsterdam, The Netherlands
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12
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Ward L, Evans SE, Stern CD. A resegmentation-shift model for vertebral patterning. J Anat 2016; 230:290-296. [PMID: 27580767 PMCID: PMC5244455 DOI: 10.1111/joa.12540] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2016] [Indexed: 11/27/2022] Open
Abstract
Segmentation of the vertebrate body axis is established in the embryo by formation of somites, which give rise to the axial muscles (myotome) and vertebrae (sclerotome). To allow a muscle to attach to two successive vertebrae, the myotome and sclerotome must be repositioned by half a segment with respect to each other. Two main models have been put forward: ‘resegmentation’ proposes that each half‐sclerotome joins with the half‐sclerotome from the next adjacent somite to form a vertebra containing cells from two successive somites on each side of the midline. The second model postulates that a single vertebra is made from a single somite and that the sclerotome shifts with respect to the myotome. There is conflicting evidence for these models, and the possibility that the mechanism may vary along the vertebral column has not been considered. Here we use DiI and DiO to trace somite contributions to the vertebrae in different axial regions in the chick embryo. We demonstrate that vertebral bodies and neural arches form by resegmentation but that sclerotome cells shift in a region‐specific manner according to their dorsoventral position within a segment. We propose a ‘resegmentation‐shift’ model as the mechanism for amniote vertebral patterning.
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Affiliation(s)
- Lizzy Ward
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Susan E Evans
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, London, UK
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13
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Williams DR, Shifley ET, Braunreiter KM, Cole SE. Disruption of somitogenesis by a novel dominant allele of Lfng suggests important roles for protein processing and secretion. Development 2016; 143:822-30. [PMID: 26811377 DOI: 10.1242/dev.128538] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/14/2016] [Indexed: 12/29/2022]
Abstract
Vertebrate somitogenesis is regulated by a segmentation clock. Clock-linked genes exhibit cyclic expression, with a periodicity matching the rate of somite production. In mice, lunatic fringe (Lfng) expression oscillates, and LFNG protein contributes to periodic repression of Notch signaling. We hypothesized that rapid LFNG turnover could be regulated by protein processing and secretion. Here, we describe a novel Lfng allele (Lfng(RLFNG)), replacing the N-terminal sequences of LFNG, which allow for protein processing and secretion, with the N-terminus of radical fringe (a Golgi-resident protein). This allele is predicted to prevent protein secretion without altering the activity of LFNG, thus increasing the intracellular half-life of the protein. This allele causes dominant skeletal and somite abnormalities that are distinct from those seen in Lfng loss-of-function embryos. Expression of clock-linked genes is perturbed and mature Hes7 transcripts are stabilized in the presomitic mesoderm of mutant mice, suggesting that both transcriptional and post-transcriptional regulation of clock components are perturbed by RLFNG expression. Contrasting phenotypes in the segmentation clock and somite patterning of mutant mice suggest that LFNG protein may have context-dependent effects on Notch activity.
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Affiliation(s)
- Dustin R Williams
- The Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Emily T Shifley
- The Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY 41099, USA
| | - Kara M Braunreiter
- The Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Susan E Cole
- The Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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14
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Early development of the vertebral column. Semin Cell Dev Biol 2016; 49:83-91. [DOI: 10.1016/j.semcdb.2015.11.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 11/05/2015] [Indexed: 11/20/2022]
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15
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Fleming A, Kishida MG, Kimmel CB, Keynes RJ. Building the backbone: the development and evolution of vertebral patterning. Development 2015; 142:1733-44. [PMID: 25968309 DOI: 10.1242/dev.118950] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The segmented vertebral column comprises a repeat series of vertebrae, each consisting of two key components: the vertebral body (or centrum) and the vertebral arches. Despite being a defining feature of the vertebrates, much remains to be understood about vertebral development and evolution. Particular controversy surrounds whether vertebral component structures are homologous across vertebrates, how somite and vertebral patterning are connected, and the developmental origin of vertebral bone-mineralizing cells. Here, we assemble evidence from ichthyologists, palaeontologists and developmental biologists to consider these issues. Vertebral arch elements were present in early stem vertebrates, whereas centra arose later. We argue that centra are homologous among jawed vertebrates, and review evidence in teleosts that the notochord plays an instructive role in segmental patterning, alongside the somites, and contributes to mineralization. By clarifying the evolutionary relationship between centra and arches, and their varying modes of skeletal mineralization, we can better appreciate the detailed mechanisms that regulate and diversify vertebral patterning.
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Affiliation(s)
- Angeleen Fleming
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Marcia G Kishida
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
| | - Charles B Kimmel
- Institute of Neuroscience, 1254 University of Oregon, Eugene OR 97403-1254, USA
| | - Roger J Keynes
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
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16
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Karaca E, Yuregir OO, Bozdogan ST, Aslan H, Pehlivan D, Jhangiani SN, Akdemir ZC, Gambin T, Bayram Y, Atik MM, Erdin S, Muzny D, Gibbs RA, Lupski JR. Rare variants in the notch signaling pathway describe a novel type of autosomal recessive Klippel-Feil syndrome. Am J Med Genet A 2015; 167A:2795-9. [PMID: 26238661 DOI: 10.1002/ajmg.a.37263] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/24/2015] [Indexed: 01/10/2023]
Abstract
Klippel-Feil syndrome is a rare disorder represented by a subgroup of segmentation defects of the vertebrae and characterized by fusion of the cervical vertebrae, low posterior hairline, and short neck with limited motion. Both autosomal dominant and recessive inheritance patterns were reported in families with Klippel-Feil. Mutated genes for both dominant (GDF6 and GDF3) and recessive (MEOX1) forms of Klippel-Feil syndrome have been shown to be involved in somite development via transcription regulation and signaling pathways. Heterotaxy arises from defects in proteins that function in the development of left-right asymmetry of the developing embryo. We describe a consanguineous family with a male proband who presents with classical Klippel-Feil syndrome together with heterotaxy (situs inversus totalis). The present patient also had Sprengel's deformity, deformity of the sternum, and a solitary kidney. Using exome sequencing, we identified a homozygous frameshift mutation (c.299delT; p.L100fs) in RIPPLY2, a gene shown to play a crucial role in somitogenesis and participate in the Notch signaling pathway via negatively regulating Tbx6. Our data confirm RIPPLY2 as a novel gene for autosomal recessive Klippel-Feil syndrome, and in addition-from a mechanistic standpoint-suggest the possibility that mutations in RIPPLY2 could also lead to heterotaxy. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ozge O Yuregir
- Department of Medical Genetics, Numune Training and Research Hospital, Adana, Turkey
| | | | - Huseyin Aslan
- Department of Medical Genetics, Medical Faculty of Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Shalini N Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Zeynep C Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Mehmed M Atik
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Serkan Erdin
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Donna Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Houston, Texas
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