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Ghimire SR, Ratzan EM, Deans MR. A non-autonomous function of the core PCP protein VANGL2 directs peripheral axon turning in the developing cochlea. Development 2018; 145:dev.159012. [PMID: 29784671 DOI: 10.1242/dev.159012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 05/14/2018] [Indexed: 01/02/2023]
Abstract
The cochlea is innervated by neurons that relay sound information from hair cells to central auditory targets. A subset of these are the type II spiral ganglion neurons, which have nociceptive features and contribute to feedback circuits providing neuroprotection in extreme noise. Type II neurons make a distinctive 90° turn towards the cochlear base to synapse with 10-15 outer hair cells. We demonstrate that this axon turning event requires planar cell polarity (PCP) signaling and is disrupted in Vangl2 and Celsr1 knockout mice, and that VANGL2 acts non-autonomously from the cochlea to direct turning. Moreover, VANGL2 is asymmetrically distributed at intercellular junctions between cochlear supporting cells, and in a pattern that could allow it to act directly as an axon guidance cue. Together, these data reveal a non-autonomous function for PCP signaling during axon guidance occurring in the tissue that is innervated, rather than the navigating growth cone.
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Affiliation(s)
- Satish R Ghimire
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Evan M Ratzan
- Interdepartmental Program in Neuroscience, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Michael R Deans
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA .,Interdepartmental Program in Neuroscience, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.,Department of Surgery, Division of Otolaryngology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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52
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Planar Cell Polarity Signaling in Mammalian Cardiac Morphogenesis. Pediatr Cardiol 2018; 39:1052-1062. [PMID: 29564519 PMCID: PMC5959767 DOI: 10.1007/s00246-018-1860-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/06/2018] [Indexed: 01/16/2023]
Abstract
The mammalian heart is the first organ to form and is critical for embryonic survival and development. With an occurrence of 1%, congenital heart defects (CHDs) are also the most common birth defects in humans, and major cause of childhood morbidity and mortality (Hoffman and Kaplan in J Am Coll Cardiol 39(12):1890-1900, 2002; Samanek in Cardiol Young 10(3):179-185, 2000). Understanding how the heart forms will not only help to determine the etiology and to design diagnostic and therapeutic approaches for CHDs, but may also provide insight into regenerative medicine to repair injured adult hearts. Mammalian heart development requires precise orchestration of growth, differentiation, and morphogenesis to remodel a simple linear heart tube into an intricate, four-chambered heart with properly connected pulmonary artery and aorta, a structural basis for establishing the pulmonary and systemic circulation. Here we will review the recent advance in our understanding of how the planar cell polarity pathway, a highly conserved morphogenetic engine in vertebrates, regulates polarized morphogenetic processes to contribute to both the arterial and venous poles development of the heart.
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53
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Chen Z, Lei Y, Cao X, Zheng Y, Wang F, Bao Y, Peng R, Finnell RH, Zhang T, Wang H. Genetic analysis of Wnt/PCP genes in neural tube defects. BMC Med Genomics 2018; 11:38. [PMID: 29618362 PMCID: PMC5885375 DOI: 10.1186/s12920-018-0355-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/19/2018] [Indexed: 11/23/2022] Open
Abstract
Background Mouse homozygous mutants in Wnt/planar cell polarity (PCP) pathway genes have been shown to cause neural tube defects (NTDs) through the disruption of normal morphogenetic processes critical to neural tube closure (NTC). Knockout mice that are heterozygotes of single PCP genes likely fail to produce NTD phenotypes, yet damaging variants detected in human NTDs are almost always heterozygous, suggesting that other deleterious interacting variants are likely to be present. Nonetheless, the Wnt/PCP pathway remains a genetic hotspot. Addressing these issues is essential for understanding the genetic etiology of human NTDs. Methods We performed targeted next-generation sequencing (NGS) on 30 NTD-predisposing Wnt/PCP pathway genes in 184 Chinese NTD cases. We subsequently replicated our findings for the CELSR1 gene in an independent cohort of 292 Caucasian NTD samples from the USA. Functional validations were confirmed using in vitro assays. Results CELSR1, CELSR2 and CELSR3 genes were significantly clustered with rare driver coding mutations (q-value< 0.05) demonstrated by OncodriveCLUST. During the validation stage, the number of rare loss of function (LoF) variants in CELSR1 was significantly enriched in NTDs compared with the LoF counts in the ExAC database (p < 0.001). Functional studies indicated compound heterozygote variants of CELSR2 p.Thr2026Met and DVL3 p.Asp403Asn result in down regulation of PCP signals. Conclusions These data indicate rare damaging variants of the CELSR genes, identified in ~ 14% of NTD cases, are expected to be driver genes in the Wnt/PCP pathway. Compound damaging variants of CELSR genes and other Wnt/PCP genes, which were observed in 3.3% of the studied NTD cohort, are also expected to amplify these effects at the pathway level. Electronic supplementary material The online version of this article (10.1186/s12920-018-0355-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhongzhong Chen
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, 200011, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, 200032, China
| | - Yunping Lei
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xuanye Cao
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yufang Zheng
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, 200011, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, 200032, China.,Children's Hospital and Institutes of Biomedical Sciences of Fudan University, Shanghai, China
| | - Fang Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, 100020, China
| | - Yihua Bao
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, 100020, China
| | - Rui Peng
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, 200011, China
| | - Richard H Finnell
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, 200011, China. .,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, 200032, China. .,Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, TX, 78723, USA.
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, 100020, China.
| | - Hongyan Wang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, 200011, China. .,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, 200032, China. .,Children's Hospital and Institutes of Biomedical Sciences of Fudan University, Shanghai, China.
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Daple coordinates organ-wide and cell-intrinsic polarity to pattern inner-ear hair bundles. Proc Natl Acad Sci U S A 2017; 114:E11170-E11179. [PMID: 29229865 PMCID: PMC5748220 DOI: 10.1073/pnas.1716522115] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Each hair cell of our auditory and vestibular systems transduces stimuli into electrical signals through its mechanosensitive hair bundle. Because the bundle is responsive along only a single axis, its orientation is crucial. Two systems determine hair-bundle polarity: planar cell polarity proteins, which establish axes along which hair cells are oriented, and the proteins Gαi and LGN. Investigating how these two systems are coordinated so that each hair bundle is appropriately aligned, we identified Daple. In mutants lacking Daple, hair bundles are misoriented and misshapen, a phenotype suggestive of both organ-wide and cell-intrinsic defects. Our study indicates how Daple interacts with proteins of the two systems and proposes a model for its role in determining hair-bundle polarity. The establishment of planar polarization by mammalian cells necessitates the integration of diverse signaling pathways. In the inner ear, at least two systems regulate the planar polarity of sensory hair bundles. The core planar cell polarity (PCP) proteins coordinate the orientations of hair cells across the epithelial plane. The cell-intrinsic patterning of hair bundles is implemented independently by the G protein complex classically known for orienting the mitotic spindle. Although the primary cilium also participates in each of these pathways, its role and the integration of the two systems are poorly understood. We show that Dishevelled-associating protein with a high frequency of leucine residues (Daple) interacts with PCP and cell-intrinsic signals. Regulated by the cell-intrinsic pathway, Daple is required to maintain the polarized distribution of the core PCP protein Dishevelled and to position the primary cilium at the abneural edge of the apical surface. Our results suggest that the primary cilium or an associated structure influences the domain of cell-intrinsic signals that shape the hair bundle. Daple is therefore essential to orient and pattern sensory hair bundles.
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55
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Strubberg AM, Liu J, Walker NM, Stefanski CD, MacLeod RJ, Magness ST, Clarke LL. Cftr Modulates Wnt/β-Catenin Signaling and Stem Cell Proliferation in Murine Intestine. Cell Mol Gastroenterol Hepatol 2017; 5:253-271. [PMID: 29675451 PMCID: PMC5904038 DOI: 10.1016/j.jcmgh.2017.11.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/18/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Cystic fibrosis (CF) patients and CF mouse models have increased risk for gastrointestinal tumors. CF mice show augmented intestinal proliferation of unknown etiology and an altered intestinal environment. We examined the role of the cystic fibrosis transmembrane conductance regulator (Cftr) in Wnt/β-catenin signaling, stem cell proliferation, and its functional expression in the active intestinal stem cell (ISC) population. Dysregulation of intracellular pH (pHi) in CF ISCs was investigated for facilitation of Wnt/β-catenin signaling. METHODS Crypt epithelia from wild-type (WT) and CF mice were compared ex vivo and in intestinal organoids (enteroids) for proliferation and Wnt/β-catenin signaling by standard assays. Cftr in ISCs was assessed by immunoblot of sorted Sox9 enhanced green fluorescent protein(EGFP) intestinal epithelia and pHi regulation by confocal microfluorimetry of leucine-rich G-protein-coupled receptor 5 ISCs. Plasma membrane association of the Wnt transducer Dishevelled 2 (Dvl2) was assessed by fluorescence imaging of live enteroids from WT and CF mice crossed with Dvl2-EGFP/ACTB-tdTomato,-EGFP)Luo/J (RosamT/mG) mice. RESULTS Relative to WT, CF intestinal crypts showed an ∼30% increase in epithelial and Lgr5+ ISC proliferation and increased Wnt/β-catenin signaling. Cftr was expressed in Sox9EGFPLo ISCs and loss of Cftr induced an alkaline pHi in ISCs. CF crypt-base columnar cells showed a generalized increase in plasma membrane Dvl2-EGFP association as compared with WT. Dvl2-EGFP membrane association was charge- and pH-dependent and increased in WT crypt-base columnar cells by Cftr inhibition. CONCLUSIONS CF intestine shows increased ISC proliferation and Wnt/β-catenin signaling. Loss of Cftr increases pHi in ISCs, which stabilizes the plasma membrane association of the Wnt transducer Dvl, likely facilitating Wnt/β-catenin signaling. Absence of Cftr-dependent suppression of ISC proliferation in the CF intestine may contribute to increased risk for intestinal tumors.
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Key Words
- CBC, crypt-base columnar cell
- CCH, carbachol
- CF, cystic fibrosis
- Cftr, cystic fibrosis transmembrane conductance regulator
- Cystic Fibrosis
- DEP, Dishevelled, Egl-10, and Pleckstrin
- Dishevelled
- Dvl, Dishevelled
- EGFP, enhanced green fluorescent protein
- EdU, 5-ethynyl-2’-deoxyuridine
- Fz, Frizzled
- GI, gastrointestinal
- ISC, intestinal stem cell
- Intracellular pH
- KO, knockout
- Lgr5, leucine-rich G-protein–coupled receptor 5
- Neoplasia
- Organoids
- PBS, phosphate-buffered saline
- PDZ, Post synaptic density protein, Drosophila disc large tumor suppressor, and Zonula occludens-1 protein
- PH3, phospho-histone H3
- ROI, region of interest
- WT, wild type
- pHi, intracellular pH
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Affiliation(s)
- Ashlee M. Strubberg
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Jinghua Liu
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Nancy M. Walker
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Casey D. Stefanski
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - R. John MacLeod
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Scott T. Magness
- Department of Medicine, Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Lane L. Clarke
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri,Correspondence Address correspondence to: Lane L. Clarke, DVM, PhD, 324D Dalton Cardiovascular Research Center, University of Missouri, 134 Research Park Drive, Columbia, Missouri 65211-3300. fax: (573) 884–4232.
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56
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Abstract
Epithelial tubes are crucial to the function of organ systems including the excretory, gastrointestinal, cardiovascular, and pulmonary. Studies in the last two decades using in vitro organotypic systems and a variety of animal models have substantiated a large number of the morphogenetic mechanisms required to form epithelial tubes in development and regeneration. Many of these mechanisms modulate the differentiation and proliferation events necessary for generating the cell movements and changes in cell shape to delineate the wide variety of epithelial tube sizes, lengths, and conformations. For instance, when coupled with oriented cell division, proliferation itself plays a role in changes in tube shape and their directed expansion. Most of these processes are regulated in response to signaling inputs from adjacent cells or soluble factors from the environment. Despite the great deal of recent investigation in this direction, the knowledge we have about the signaling pathways associated with all epithelial tubulogenesis in development and regeneration is still very limited.
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57
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Yang W, Garrett L, Feng D, Elliott G, Liu X, Wang N, Wong YM, Choi NT, Yang Y, Gao B. Wnt-induced Vangl2 phosphorylation is dose-dependently required for planar cell polarity in mammalian development. Cell Res 2017; 27:1466-1484. [PMID: 29056748 DOI: 10.1038/cr.2017.127] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 05/16/2017] [Accepted: 08/20/2017] [Indexed: 12/12/2022] Open
Abstract
Planar cell polarity (PCP) is an evolutionarily conserved essential mechanism that provides directional information to control and coordinate polarized cellular and tissue behavior during embryonic development. Disruption of PCP leads to severe morphological defects in vertebrates and its dysregulation results in a variety of human diseases such as neural tube defects and skeletal dysplasia. PCP is governed by a set of highly conserved core proteins that are asymmetrically localized at the cell surface throughout the polarized tissues. The uniform directionality of PCP is established by global cues, such as Wg/Wnt signaling gradients that break the original symmetrical localization of core PCP proteins including Vang/Vangl and Fz/Fzd. However, the exact mechanism remains elusive. In this study, we found that Vangl2 phosphorylation, which was previously identified to be induced by Wnt5a signaling, is required for Vangl2 functions in mammalian PCP in multiple tissues. The in vivo activities of Vangl2 are determined by its phosphorylation level. Phospho-mutant Vangl2 exhibits dominant negative effects, whereas Vangl2 with reduced phosphorylation is hypomorphic. We show that Vangl2 phosphorylation is essential for its uniform polarization pattern. Moreover, serine/threonine kinases CK1ɛ and CK1δ are redundantly required for Wnt5a-induced Vangl2 phosphorylation. Dvl family members are also required for Wnt5a-induced Vangl2 phosphorylation by enhancing the interaction of CK1 and Vangl2. These findings demonstrate that induction of Vangl protein phosphorylation plays an essential role in transducing Wnt5a signaling to establish PCP in mammalian development, suggesting a phosphorylation-regulated "Vangl activity gradient" model in addition to the well-documented "Fz activity gradient" model in Wnt/PCP signaling.
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Affiliation(s)
- Wei Yang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Lisa Garrett
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Di Feng
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Gene Elliott
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xilin Liu
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.,China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, China
| | - Ni Wang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Yu Ming Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Nga Ting Choi
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Yingzi Yang
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Developmental Biology, Harvard School of Dental Medicine, 188 Longwood Ave., Boston, MA 02115, USA
| | - Bo Gao
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China.,National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.,Centre for Reproduction, Development and Growth & HKU-SUSTEC Joint Laboratories of Matrix Biology and Diseases, The University of Hong Kong, Pokfulam, Hong Kong, China
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58
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Seo HS, Habas R, Chang C, Wang J. Bimodal regulation of Dishevelled function by Vangl2 during morphogenesis. Hum Mol Genet 2017; 26:2053-2061. [PMID: 28334810 DOI: 10.1093/hmg/ddx095] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/07/2017] [Indexed: 12/28/2022] Open
Abstract
Convergent extension (CE) is a fundamental morphogenetic mechanism that underlies numerous processes in vertebrate development, and its disruption can lead to human congenital disorders such as neural tube closure defects. The dynamic, oriented cell intercalation during CE is regulated by a group of core proteins identified originally in flies to coordinate epithelial planar cell polarity (PCP). The existing model explains how core PCP proteins, including Van Gogh (Vang) and Dishevelled (Dvl), segregate into distinct complexes on opposing cell cortex to coordinate polarity among static epithelial cells. The action of core PCP proteins in the dynamic process of CE, however, remains an enigma. In this report, we show that Vangl2 (Vang-like 2) exerts dual positive and negative regulation on Dvl during CE in both the mouse and Xenopus. We find that Vangl2 binds to Dvl to cell-autonomously promote efficient Dvl plasma membrane recruitment, a pre-requisite for PCP activation. At the same time, Vangl2 inhibits Dvl from interacting with its downstream effector Daam1 (Dishevelled associated activator of morphogenesis 1), and functionally suppresses Dvl → Daam1 cascade during CE. Our finding uncovers Vangl2-Dvl interaction as a key bi-functional switch that underlies the central logic of PCP signaling during morphogenesis, and provides new insight into PCP-related disorders in humans.
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Affiliation(s)
- Hwa-Seon Seo
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Raymond Habas
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Chenbei Chang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jianbo Wang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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59
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Abstract
The planar cell polarity (PCP) pathway is best known for its role in polarizing epithelial cells within the plane of a tissue but it also plays a role in a range of cell migration events during development. The mechanism by which the PCP pathway polarizes stationary epithelial cells is well characterized, but how PCP signaling functions to regulate more dynamic cell behaviors during directed cell migration is much less understood. Here, we review recent discoveries regarding the localization of PCP proteins in migrating cells and their impact on the cell biology of collective and individual cell migratory behaviors.
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Affiliation(s)
- Crystal F Davey
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, B2-159, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Cecilia B Moens
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, B2-159, 1100 Fairview Ave. N., Seattle, WA 98109, USA
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60
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Driver EC, Northrop A, Kelley MW. Cell migration, intercalation and growth regulate mammalian cochlear extension. Development 2017; 144:3766-3776. [PMID: 28870992 DOI: 10.1242/dev.151761] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/24/2017] [Indexed: 01/01/2023]
Abstract
Developmental remodeling of the sensory epithelium of the cochlea is required for the formation of an elongated, tonotopically organized auditory organ, but the cellular processes that mediate these events are largely unknown. We used both morphological assessments of cellular rearrangements and time-lapse imaging to visualize cochlear remodeling in mouse. Analysis of cell redistribution showed that the cochlea extends through a combination of radial intercalation and cell growth. Live imaging demonstrated that concomitant cellular intercalation results in a brief period of epithelial convergence, although subsequent changes in cell size lead to medial-lateral spreading. Supporting cells, which retain contact with the basement membrane, exhibit biased protrusive activity and directed movement along the axis of extension. By contrast, hair cells lose contact with the basement membrane, but contribute to continued outgrowth through increased cell size. Regulation of cellular protrusions, movement and intercalation within the cochlea all require myosin II. These results establish, for the first time, many of the cellular processes that drive the distribution of sensory cells along the tonotopic axis of the cochlea.
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Affiliation(s)
- Elizabeth Carroll Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
| | - Amy Northrop
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
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61
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Prickle1 regulates neurite outgrowth of apical spiral ganglion neurons but not hair cell polarity in the murine cochlea. PLoS One 2017; 12:e0183773. [PMID: 28837644 PMCID: PMC5570324 DOI: 10.1371/journal.pone.0183773] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 08/10/2017] [Indexed: 01/05/2023] Open
Abstract
In the mammalian organ of Corti (OC), the stereocilia on the apical surface of hair cells (HCs) are uniformly organized in a neural to abneural axis (or medial-laterally). This organization is regulated by planar cell polarity (PCP) signaling. Mutations of PCP genes, such as Vangl2, Dvl1/2, Celsr1, and Fzd3/6, affect the formation of HC orientation to varying degrees. Prickle1 is a PCP signaling gene that belongs to the prickle / espinas / testin family. Prickle1 protein is shown to be asymmetrically localized in the HCs of the OC, and this asymmetric localization is associated with loss of PCP in Smurf mutants, implying that Prickle1 is involved in HC PCP development in the OC. A follow-up study found no PCP polarity defects after loss of Prickle1 (Prickle1-/-) in the cochlea. We show here strong Prickle1 mRNA expression in the spiral ganglion by in situ hybridization and β-Gal staining, and weak expression in the OC by β-Gal staining. Consistent with this limited expression in the OC, cochlear HC PCP is unaffected in either Prickle1C251X/C251X mice or Prickle1f/f; Pax2-cre conditional null mice. Meanwhile, type II afferents of apical spiral ganglion neurons (SGN) innervating outer hair cells (OHC) have unusual neurite growth. In addition, afferents from the apex show unusual collaterals in the cochlear nuclei that overlap with basal turn afferents. Our findings argue against the role of Prickle1 in regulating hair cell polarity in the cochlea. Instead, Prickle1 regulates the polarity-related growth of distal and central processes of apical SGNs.
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62
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Abstract
The claudin family of tetraspan transmembrane proteins is essential for tight junction formation and regulation of paracellular transport between epithelial cells. Claudins also play a role in apical-basal cell polarity, cell adhesion and link the tight junction to the actin cytoskeleton to exert effects on cell shape. The function of claudins in paracellular transport has been extensively studied through loss-of-function and gain-of-function studies in cell lines and in animal models, however, their role in morphogenesis has been less appreciated. In this review, we will highlight the importance of claudins during morphogenesis by specifically focusing on their critical functions in generating epithelial tubes, lumens, and tubular networks during organ formation.
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Affiliation(s)
- Amanda I Baumholtz
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada
| | - Indra R Gupta
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada.,c Department of Pediatrics , McGill University , Montréal , Québec , Canada
| | - Aimee K Ryan
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada.,c Department of Pediatrics , McGill University , Montréal , Québec , Canada
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63
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Ni T, Gilbert RJC. Repurposing a pore: highly conserved perforin-like proteins with alternative mechanisms. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160212. [PMID: 28630152 PMCID: PMC5483515 DOI: 10.1098/rstb.2016.0212] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2017] [Indexed: 12/02/2022] Open
Abstract
Pore-forming proteins play critical roles in pathogenic attack and immunological defence. The membrane attack complex/perforin (MACPF) group of homologues represents, with cholesterol-dependent cytolysins, the largest family of such proteins. In this review, we begin by describing briefly the structure of MACPF proteins, outlining their common mechanism of pore formation. We subsequently discuss some examples of MACPF proteins likely implicated in pore formation or other membrane-remodelling processes. Finally, we focus on astrotactin and bone morphogenetic protein and retinoic acid-induced neural-specific proteins, highly conserved MACPF family members involved in developmental processes, which have not been well studied to date or observed to form a pore-and which data suggest may act by alternative mechanisms.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Tao Ni
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Robert J C Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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Seven pass Cadherins CELSR1-3. Semin Cell Dev Biol 2017; 69:102-110. [PMID: 28716607 DOI: 10.1016/j.semcdb.2017.07.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 11/20/2022]
Abstract
Cadherin EGF LAG seven-pass G-type receptors 1, 2 and 3 (CELSR1-3) form a family of three atypical cadherins with multiple functions in epithelia and in the nervous system. During the past decade, evidence has accumulated for a key role of CELSR1 in epithelial planar cell polarity (PCP), and for CELSR2 and CELSR3 in ciliogenesis and neural development, especially neuron migration and axon guidance in the central, peripheral and enteric nervous systems. Phenotypes in mutant mice indicate that CELSR proteins work in concert with FZD3 and FZD6, but several questions remain. Apart from PCP signaling pathways implicating CELSR1 that begin to be unraveled, little is known about other signals generated by CELSR2 and CELSR3. A crucial question concerns the putative ligands that trigger signaling, in particular what is the role of WNT factors. Another critical issue is the identification of novel intracellular pathways and effectors that relay and transmit signals in receptive cells? Answers to those questions should further our understanding of the role of those important molecules not only in development but also in regeneration and disease.
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65
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Williams ML, Solnica-Krezel L. Regulation of gastrulation movements by emergent cell and tissue interactions. Curr Opin Cell Biol 2017; 48:33-39. [PMID: 28586710 DOI: 10.1016/j.ceb.2017.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 04/30/2017] [Indexed: 10/19/2022]
Abstract
It is during gastrulation that the primordial germ layers are specified, embryonic axes become morphologically manifest, and the embryonic body plan begins to take shape. As morphogenetic movements push and pull nascent tissues into position within the gastrula, new interactions are established between neighboring cells and tissues. These interactions represent an emergent property within gastrulating embryos, and serve to regulate and promote ensuing morphogenesis that establishes the next set of cell/tissue contacts, and so on. Several recent studies demonstrate the critical roles of such interactions during gastrulation, including those between germ layers, along embryonic axes, and at tissue boundaries. Emergent tissue interactions result from - and result in - morphogen signaling, cell contacts, and mechanical forces within the gastrula. Together, these comprise a dynamic and complex regulatory cascade that drives gastrulation morphogenesis.
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Affiliation(s)
- Margot Lk Williams
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lilianna Solnica-Krezel
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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66
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Gentzel M, Schambony A. Dishevelled Paralogs in Vertebrate Development: Redundant or Distinct? Front Cell Dev Biol 2017; 5:59. [PMID: 28603713 PMCID: PMC5445114 DOI: 10.3389/fcell.2017.00059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/12/2017] [Indexed: 01/21/2023] Open
Abstract
Dishevelled (DVL) proteins are highly conserved in the animal kingdom and are important key players in β-Catenin-dependent and -independent Wnt signaling pathways. Vertebrate genomes typically comprise three DVL genes, DVL1, DVL2, and DVL3. Expression patterns and developmental functions of the three vertebrate DVL proteins however, are only partially redundant in any given species. Moreover, expression and function of DVL isoforms have diverged between different vertebrate species. All DVL proteins share basic functionality in Wnt signal transduction. Additional, paralog-specific interactions and functions combined with context-dependent availability of DVL isoforms may play a central role in defining Wnt signaling specificity and add selectivity toward distinct downstream pathways. In this review, we recapitulate briefly cellular functions of DVL paralogs, their role in vertebrate embryonic development and congenital disease.
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Affiliation(s)
- Marc Gentzel
- Molecular Analysis-Mass Spectrometry, Center for Molecular and Cellular Bioengineering (CMCB), TU DresdenDresden, Germany
| | - Alexandra Schambony
- Developmental Biology, Biology Department, Friedrich-Alexander University Erlangen-NurembergErlangen, Germany
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67
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Baumholtz AI, Simard A, Nikolopoulou E, Oosenbrug M, Collins MM, Piontek A, Krause G, Piontek J, Greene NDE, Ryan AK. Claudins are essential for cell shape changes and convergent extension movements during neural tube closure. Dev Biol 2017; 428:25-38. [PMID: 28545845 PMCID: PMC5523803 DOI: 10.1016/j.ydbio.2017.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/08/2017] [Accepted: 05/14/2017] [Indexed: 11/29/2022]
Abstract
During neural tube closure, regulated changes at the level of individual cells are translated into large-scale morphogenetic movements to facilitate conversion of the flat neural plate into a closed tube. Throughout this process, the integrity of the neural epithelium is maintained via cell interactions through intercellular junctions, including apical tight junctions. Members of the claudin family of tight junction proteins regulate paracellular permeability, apical-basal cell polarity and link the tight junction to the actin cytoskeleton. Here, we show that claudins are essential for neural tube closure: the simultaneous removal of Cldn3, −4 and −8 from tight junctions caused folate-resistant open neural tube defects. Their removal did not affect cell type differentiation, neural ectoderm patterning nor overall apical-basal polarity. However, apical accumulation of Vangl2, RhoA, and pMLC were reduced, and Par3 and Cdc42 were mislocalized at the apical cell surface. Our data showed that claudins act upstream of planar cell polarity and RhoA/ROCK signaling to regulate cell intercalation and actin-myosin contraction, which are required for convergent extension and apical constriction during neural tube closure, respectively. Simultaneous removal of Cldn3, −4 and −8 causes open neural tube defects. Folic acid cannot rescue open NTDs caused by depletion of Cldn3, −4 and −8. Removal of Cldn3, −4 and −8 prevents convergent extension. Apical constriction to form the median hinge point requires Cldn3, −4 and −8. Claudins localize polarity complex components to the apical surface.
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Affiliation(s)
- Amanda I Baumholtz
- Department of Human Genetics, McGill University, Canada; The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
| | - Annie Simard
- Department of Experimental Medicine, McGill University, Canada; The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
| | - Evanthia Nikolopoulou
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, UCL Institute of Child Health, London, UK.
| | - Marcus Oosenbrug
- Department of Anatomy and Cell Biology, McGill University, Canada; The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
| | - Michelle M Collins
- Department of Human Genetics, McGill University, Canada; The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
| | - Anna Piontek
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, FMP, Berlin, Germany.
| | - Gerd Krause
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, FMP, Berlin, Germany.
| | - Jörg Piontek
- Institute of Clinical Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Nicholas D E Greene
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, UCL Institute of Child Health, London, UK.
| | - Aimee K Ryan
- Department of Human Genetics, McGill University, Canada; Department of Experimental Medicine, McGill University, Canada; Department of Pediatrics, McGill University, Canada; The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
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68
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Butler MT, Wallingford JB. Planar cell polarity in development and disease. Nat Rev Mol Cell Biol 2017; 18:375-388. [PMID: 28293032 DOI: 10.1038/nrm.2017.11] [Citation(s) in RCA: 345] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Planar cell polarity (PCP) is an essential feature of animal tissues, whereby distinct polarity is established within the plane of a cell sheet. Tissue-wide establishment of PCP is driven by multiple global cues, including gradients of gene expression, gradients of secreted WNT ligands and anisotropic tissue strain. These cues guide the dynamic, subcellular enrichment of PCP proteins, which can self-assemble into mutually exclusive complexes at opposite sides of a cell. Endocytosis, endosomal trafficking and degradation dynamics of PCP components further regulate planar tissue patterning. This polarization propagates throughout the whole tissue, providing a polarity axis that governs collective morphogenetic events such as the orientation of subcellular structures and cell rearrangements. Reflecting the necessity of polarized cellular behaviours for proper development and function of diverse organs, defects in PCP have been implicated in human pathologies, most notably in severe birth defects.
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Affiliation(s)
- Mitchell T Butler
- Department of Molecular Biosciences, Patterson Labs, 2401 Speedway, The University of Texas at Austin, Austin, Texas 78712, USA
| | - John B Wallingford
- Department of Molecular Biosciences, Patterson Labs, 2401 Speedway, The University of Texas at Austin, Austin, Texas 78712, USA
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69
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Qi J, Lee HJ, Saquet A, Cheng XN, Shao M, Zheng JJ, Shi DL. Autoinhibition of Dishevelled protein regulated by its extreme C terminus plays a distinct role in Wnt/β-catenin and Wnt/planar cell polarity (PCP) signaling pathways. J Biol Chem 2017; 292:5898-5908. [PMID: 28223363 DOI: 10.1074/jbc.m116.772509] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/19/2017] [Indexed: 12/20/2022] Open
Abstract
Dishevelled (Dvl) is a key intracellular signaling molecule that mediates the activation of divergent Wnt pathways. It contains three highly conserved domains known as DIX, PDZ, and DEP, the functions of which have been well characterized in β-catenin-dependent canonical and β-catenin-independent noncanonical Wnt signaling. The C-terminal region is also highly conserved from invertebrates to vertebrates. However, its function in regulating the activation of different Wnt signals remains unclear. We reported previously that Dvl conformational change triggered by the highly conserved PDZ-binding C terminus is important for the pathway specificity. Here we provide further evidence demonstrating that binding of the C terminus to the PDZ domain results in Dvl autoinhibition in the Wnt signaling pathways. Therefore, the forced binding of the C terminus to the PDZ domain reduces the activity of Dvl in noncanonical Wnt signaling, whereas obstruction of this interaction releases Dvl autoinhibition, impairs its functional interaction with LRP6 in canonical Wnt signaling, and increases its specificity in noncanonical Wnt signaling, which is closely correlated with an enhanced Dvl membrane localization. Our findings highlight the importance of the C terminus in keeping Dvl in an appropriate autoinhibited state, accessible for regulation by other partners to switch pathway specificity. Particularly, the C-terminally tagged Dvl fusion proteins that have been widely used to study the function and cellular localization of Dvl may not truly represent the wild-type Dvl because those proteins cannot be autoinhibited.
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Affiliation(s)
- Jing Qi
- From the School of Life Sciences, Shandong University, 27 Shanda Nan Road, Jinan 250100, China.,the Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan 250100, China, and
| | - Ho-Jin Lee
- the Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678
| | - Audrey Saquet
- the Institut de Biologie Paris-Seine (IBPS)-Developmental Biology Laboratory, Sorbonne Universités-Université Pierre et Marie Curie (UPMC), University of Paris 06, CNRS UMR7622, 75005 Paris, France
| | - Xiao-Ning Cheng
- From the School of Life Sciences, Shandong University, 27 Shanda Nan Road, Jinan 250100, China
| | - Ming Shao
- From the School of Life Sciences, Shandong University, 27 Shanda Nan Road, Jinan 250100, China
| | - Jie J Zheng
- the Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, .,the Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095.,the Molecular Biology Institute, UCLA, Los Angeles, California 90095
| | - De-Li Shi
- From the School of Life Sciences, Shandong University, 27 Shanda Nan Road, Jinan 250100, China, .,the Institut de Biologie Paris-Seine (IBPS)-Developmental Biology Laboratory, Sorbonne Universités-Université Pierre et Marie Curie (UPMC), University of Paris 06, CNRS UMR7622, 75005 Paris, France
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70
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Mohd-Zin SW, Marwan AI, Abou Chaar MK, Ahmad-Annuar A, Abdul-Aziz NM. Spina Bifida: Pathogenesis, Mechanisms, and Genes in Mice and Humans. SCIENTIFICA 2017; 2017:5364827. [PMID: 28286691 PMCID: PMC5327787 DOI: 10.1155/2017/5364827] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 11/14/2016] [Accepted: 12/01/2016] [Indexed: 05/26/2023]
Abstract
Spina bifida is among the phenotypes of the larger condition known as neural tube defects (NTDs). It is the most common central nervous system malformation compatible with life and the second leading cause of birth defects after congenital heart defects. In this review paper, we define spina bifida and discuss the phenotypes seen in humans as described by both surgeons and embryologists in order to compare and ultimately contrast it to the leading animal model, the mouse. Our understanding of spina bifida is currently limited to the observations we make in mouse models, which reflect complete or targeted knockouts of genes, which perturb the whole gene(s) without taking into account the issue of haploinsufficiency, which is most prominent in the human spina bifida condition. We thus conclude that the need to study spina bifida in all its forms, both aperta and occulta, is more indicative of the spina bifida in surviving humans and that the measure of deterioration arising from caudal neural tube defects, more commonly known as spina bifida, must be determined by the level of the lesion both in mouse and in man.
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Affiliation(s)
- Siti W. Mohd-Zin
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ahmed I. Marwan
- Laboratory for Fetal and Regenerative Biology, Colorado Fetal Care Center, Division of Pediatric Surgery, Children's Hospital Colorado, University of Colorado, Anschutz Medical Campus, 12700 E 17th Ave, Aurora, CO 80045, USA
| | | | - Azlina Ahmad-Annuar
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Noraishah M. Abdul-Aziz
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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71
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Duncan JS, Stoller ML, Francl AF, Tissir F, Devenport D, Deans MR. Celsr1 coordinates the planar polarity of vestibular hair cells during inner ear development. Dev Biol 2017; 423:126-137. [PMID: 28159525 DOI: 10.1016/j.ydbio.2017.01.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 11/30/2022]
Abstract
Vestibular hair cells of the inner ear are specialized receptors that detect mechanical stimuli from gravity and motion via the deflection of a polarized bundle of stereocilia located on their apical cell surfaces. The orientation of stereociliary bundles is coordinated between neighboring cells by core PCP proteins including the large adhesive G-protein coupled receptor Celsr1. We show that mice lacking Celsr1 have vestibular behavioral phenotypes including circling. In addition, we show that Celsr1 is asymmetrically distributed at cell boundaries between hair cells and neighboring supporting cells in the developing vestibular and auditory sensory epithelia. In the absence of Celsr1 the stereociliary bundles of vestibular hair cells are misoriented relative to their neighbors, a phenotype that is greatest in the cristae of the semicircular canals. Since horizontal semi-circular canal defects lead to circling in other mutant mouse lines, we propose that this PCP phenotype is the cellular basis of the circling behavior in Celsr1 mutants.
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Affiliation(s)
- Jeremy S Duncan
- Department of Surgery, Division of Otolaryngology, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Michelle L Stoller
- Department of Surgery, Division of Otolaryngology, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Andrew F Francl
- Department of Surgery, Division of Otolaryngology, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Fadel Tissir
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Danelle Devenport
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Michael R Deans
- Department of Surgery, Division of Otolaryngology, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA.
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72
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Houston DW. Vertebrate Axial Patterning: From Egg to Asymmetry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:209-306. [PMID: 27975274 PMCID: PMC6550305 DOI: 10.1007/978-3-319-46095-6_6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The emergence of the bilateral embryonic body axis from a symmetrical egg has been a long-standing question in developmental biology. Historical and modern experiments point to an initial symmetry-breaking event leading to localized Wnt and Nodal growth factor signaling and subsequent induction and formation of a self-regulating dorsal "organizer." This organizer forms at the site of notochord cell internalization and expresses primarily Bone Morphogenetic Protein (BMP) growth factor antagonists that establish a spatiotemporal gradient of BMP signaling across the embryo, directing initial cell differentiation and morphogenesis. Although the basics of this model have been known for some time, many of the molecular and cellular details have only recently been elucidated and the extent that these events remain conserved throughout vertebrate evolution remains unclear. This chapter summarizes historical perspectives as well as recent molecular and genetic advances regarding: (1) the mechanisms that regulate symmetry-breaking in the vertebrate egg and early embryo, (2) the pathways that are activated by these events, in particular the Wnt pathway, and the role of these pathways in the formation and function of the organizer, and (3) how these pathways also mediate anteroposterior patterning and axial morphogenesis. Emphasis is placed on comparative aspects of the egg-to-embryo transition across vertebrates and their evolution. The future prospects for work regarding self-organization and gene regulatory networks in the context of early axis formation are also discussed.
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Affiliation(s)
- Douglas W Houston
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA, 52242, USA.
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73
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Gammons MV, Rutherford TJ, Steinhart Z, Angers S, Bienz M. Essential role of the Dishevelled DEP domain in a Wnt-dependent human-cell-based complementation assay. J Cell Sci 2016; 129:3892-3902. [PMID: 27744318 PMCID: PMC5087658 DOI: 10.1242/jcs.195685] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 08/30/2016] [Indexed: 01/15/2023] Open
Abstract
Dishevelled (DVL) assembles Wnt signalosomes through dynamic head-to-tail polymerisation by means of its DIX domain. It thus transduces Wnt signals to cytoplasmic effectors including β-catenin, to control cell fates during normal development, tissue homeostasis and also in cancer. To date, most functional studies of Dishevelled relied on its Wnt-independent signalling activity resulting from overexpression, which is sufficient to trigger polymerisation, bypassing the requirement for Wnt signals. Here, we generate a human cell line devoid of endogenous Dishevelled (DVL1- DVL3), which lacks Wnt signal transduction to β-catenin. However, Wnt responses can be restored by DVL2 stably re-expressed at near-endogenous levels. Using this assay to test mutant DVL2, we show that its DEP domain is essential, whereas its PDZ domain is dispensable, for signalling to β-catenin. Our results imply two mutually exclusive functions of the DEP domain in Wnt signal transduction - binding to Frizzled to recruit Dishevelled to the receptor complex, and dimerising to cross-link DIX domain polymers for signalosome assembly. Our assay avoids the caveats associated with overexpressing Dishevelled, and provides a powerful tool for rigorous functional tests of this pivotal human signalling protein.
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Affiliation(s)
- Melissa V Gammons
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Trevor J Rutherford
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Zachary Steinhart
- Leslie Dan Faculty of Pharmacy, Room 901, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2
| | - Stephane Angers
- Leslie Dan Faculty of Pharmacy, Room 901, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2
| | - Mariann Bienz
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
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74
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Prenatal β-catenin/Brn2/Tbr2 transcriptional cascade regulates adult social and stereotypic behaviors. Mol Psychiatry 2016; 21:1417-33. [PMID: 26830142 PMCID: PMC5685528 DOI: 10.1038/mp.2015.207] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/01/2015] [Accepted: 11/19/2015] [Indexed: 12/17/2022]
Abstract
Social interaction is a fundamental behavior in all animal species, but the developmental timing of the social neural circuit formation and the cellular and molecular mechanisms governing its formation are poorly understood. We generated a mouse model with mutations in two Disheveled genes, Dvl1 and Dvl3, that displays adult social and repetitive behavioral abnormalities associated with transient embryonic brain enlargement during deep layer cortical neuron formation. These phenotypes were mediated by the embryonic expansion of basal neural progenitor cells (NPCs) via deregulation of a β-catenin/Brn2/Tbr2 transcriptional cascade. Transient pharmacological activation of the canonical Wnt pathway during this period of early corticogenesis rescued the β-catenin/Brn2/Tbr2 transcriptional cascade and the embryonic brain phenotypes. Remarkably, this embryonic treatment prevented adult behavioral deficits and partially rescued abnormal brain structure in Dvl mutant mice. Our findings define a mechanism that links fetal brain development and adult behavior, demonstrating a fetal origin for social and repetitive behavior deficits seen in disorders such as autism.
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75
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The role of G protein-coupled receptors in cochlear planar cell polarity. Int J Biochem Cell Biol 2016; 77:220-5. [DOI: 10.1016/j.biocel.2016.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 02/06/2023]
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76
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Belinson H, Savage AK, Fadrosh D, Kuo YM, Lin D, Valladares R, Nusse Y, Wynshaw-Boris A, Lynch SV, Locksley RM, Klein OD. Dual epithelial and immune cell function of Dvl1 regulates gut microbiota composition and intestinal homeostasis. JCI Insight 2016; 1:85395. [PMID: 27525310 DOI: 10.1172/jci.insight.85395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Homeostasis of the gastrointestinal (GI) tract is controlled by complex interactions between epithelial and immune cells and the resident microbiota. Here, we studied the role of Wnt signaling in GI homeostasis using Disheveled 1 knockout (Dvl1-/-) mice, which display an increase in whole gut transit time. This phenotype is associated with a reduction and mislocalization of Paneth cells and an increase in CD8+ T cells in the lamina propria. Bone marrow chimera experiments demonstrated that GI dysfunction requires abnormalities in both epithelial and immune cells. Dvl1-/- mice exhibit a significantly distinct GI microbiota, and manipulation of the gut microbiota in mutant mice rescued the GI transit abnormality without correcting the Paneth and CD8+ T cell abnormalities. Moreover, manipulation of the gut microbiota in wild-type mice induced a GI transit abnormality akin to that seen in Dvl1-/- mice. Together, these data indicate that microbiota manipulation can overcome host dysfunction to correct GI transit abnormalities. Our findings illustrate a mechanism by which the epithelium and immune system coregulate gut microbiota composition to promote normal GI function.
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Affiliation(s)
- Haim Belinson
- Department of Pediatrics and Institute for Human Genetics.,Department of Orofacial Sciences and Program in Craniofacial Biology
| | - Adam K Savage
- Howard Hughes Medical Institute, Department of Microbiology & Immunology, and
| | - Douglas Fadrosh
- Department of Medicine, University of California, San Francisco, California, USA
| | - Yien-Ming Kuo
- Department of Medicine, University of California, San Francisco, California, USA
| | - Din Lin
- Department of Medicine, University of California, San Francisco, California, USA
| | - Ricardo Valladares
- Department of Medicine, University of California, San Francisco, California, USA
| | - Ysbrand Nusse
- Department of Pediatrics and Institute for Human Genetics.,Department of Orofacial Sciences and Program in Craniofacial Biology
| | - Anthony Wynshaw-Boris
- Department of Pediatrics and Institute for Human Genetics.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Susan V Lynch
- Department of Medicine, University of California, San Francisco, California, USA
| | - Richard M Locksley
- Howard Hughes Medical Institute, Department of Microbiology & Immunology, and.,Department of Medicine, University of California, San Francisco, California, USA
| | - Ophir D Klein
- Department of Pediatrics and Institute for Human Genetics.,Department of Orofacial Sciences and Program in Craniofacial Biology
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77
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Abstract
UNLABELLED Mechanosensory hair cells (HCs) residing in the inner ear are critical for hearing and balance. Precise coordination of proliferation, sensory specification, and differentiation during development is essential to ensure the correct patterning of HCs in the cochlear and vestibular epithelium. Recent studies have revealed that FGF20 signaling is vital for proper HC differentiation. However, the mechanisms by which FGF20 signaling promotes HC differentiation remain unknown. Here, we show that mitogen-activated protein 3 kinase 4 (MEKK4) expression is highly regulated during inner ear development and is critical to normal cytoarchitecture and function. Mice homozygous for a kinase-inactive MEKK4 mutation exhibit significant hearing loss. Lack of MEKK4 activity in vivo also leads to a significant reduction in the number of cochlear and vestibular HCs, suggesting that MEKK4 activity is essential for overall development of HCs within the inner ear. Furthermore, we show that loss of FGF20 signaling in vivo inhibits MEKK4 activity, whereas gain of Fgf20 function stimulates MEKK4 expression, suggesting that Fgf20 modulates MEKK4 activity to regulate cellular differentiation. Finally, we demonstrate, for the first time, that MEKK4 acts as a critical node to integrate FGF20-FGFR1 signaling responses to specifically influence HC development and that FGFR1 signaling through activation of MEKK4 is necessary for outer hair cell differentiation. Collectively, this study provides compelling evidence of an essential role for MEKK4 in inner ear morphogenesis and identifies the requirement of MEKK4 expression in regulating the specific response of FGFR1 during HC development and FGF20/FGFR1 signaling activated MEKK4 for normal sensory cell differentiation. SIGNIFICANCE STATEMENT Sensory hair cells (HCs) are the mechanoreceptors within the inner ear responsible for our sense of hearing. HCs are formed before birth, and mammals lack the ability to restore the sensory deficits associated with their loss. In this study, we show, for the first time, that MEKK4 signaling is essential for the development of normal cytoarchitecture and hearing function as MEKK4 signaling-deficient mice exhibit a significant reduction of HCs and a hearing loss. We also identify MEKK4 as a critical hub kinase for FGF20-FGFR1 signaling to induce HC differentiation in the mammalian cochlea. These results reveal a new paradigm in the regulation of HC differentiation and provide significant new insights into the mechanism of Fgf signaling governing HC formation.
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78
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Davey CF, Mathewson AW, Moens CB. PCP Signaling between Migrating Neurons and their Planar-Polarized Neuroepithelial Environment Controls Filopodial Dynamics and Directional Migration. PLoS Genet 2016; 12:e1005934. [PMID: 26990447 PMCID: PMC4798406 DOI: 10.1371/journal.pgen.1005934] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 02/24/2016] [Indexed: 11/18/2022] Open
Abstract
The planar cell polarity (PCP) pathway is a cell-contact mediated mechanism for transmitting polarity information between neighboring cells. PCP “core components” (Vangl, Fz, Pk, Dsh, and Celsr) are essential for a number of cell migratory events including the posterior migration of facial branchiomotor neurons (FBMNs) in the plane of the hindbrain neuroepithelium in zebrafish and mice. While the mechanism by which PCP signaling polarizes static epithelial cells is well understood, how PCP signaling controls highly dynamic processes like neuronal migration remains an important outstanding question given that PCP components have been implicated in a range of directed cell movements, particularly during vertebrate development. Here, by systematically disrupting PCP signaling in a rhombomere-restricted manner we show that PCP signaling is required both within FBMNs and the hindbrain rhombomere 4 environment at the time when they initiate their migration. Correspondingly, we demonstrate planar polarized localization of PCP core components Vangl2 and Fzd3a in the hindbrain neuroepithelium, and transient localization of Vangl2 at the tips of retracting FBMN filopodia. Using high-resolution timelapse imaging of FBMNs in genetic chimeras we uncover opposing cell-autonomous and non-cell-autonomous functions for Fzd3a and Vangl2 in regulating FBMN protrusive activity. Within FBMNs, Fzd3a is required to stabilize filopodia while Vangl2 has an antagonistic, destabilizing role. However, in the migratory environment Fzd3a acts to destabilize FBMN filopodia while Vangl2 has a stabilizing role. Together, our findings suggest a model in which PCP signaling between the planar polarized neuroepithelial environment and FBMNs directs migration by the selective stabilization of FBMN filopodia. Planar cell polarity (PCP) is a common feature of many animal tissues. This type of polarity is most obvious in cells that are organized into epithelial sheets, where PCP signaling components act to orient cells in the plane of the tissue. Although, PCP is best understood for its function in polarizing stable epithelia, PCP is also required for the dynamic process of cell migration in animal development and disease. The goal of this study was to determine how PCP functions to control cell migration. We used the migration of facial branchiomotor neurons in the zebrafish hindbrain, which requires almost the entire suite of PCP core components, to address this question. We present evidence that PCP signaling within migrating neurons, and between migrating neurons and cells of their migratory environment promote migration by regulating filopodial dynamics. Our results suggest that broadly conserved interactions between PCP components control the cytoskeleton in motile cells and non-motile epithelia alike.
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Affiliation(s)
- Crystal F. Davey
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
| | - Andrew W. Mathewson
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
| | - Cecilia B. Moens
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
- * E-mail:
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79
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White J, Mazzeu J, Hoischen A, Bayram Y, Withers M, Gezdirici A, Kimonis V, Steehouwer M, Jhangiani S, Muzny D, Gibbs R, van Bon B, Sutton V, Lupski J, Brunner H, Carvalho C, Carvalho CMB. DVL3 Alleles Resulting in a -1 Frameshift of the Last Exon Mediate Autosomal-Dominant Robinow Syndrome. Am J Hum Genet 2016; 98:553-561. [PMID: 26924530 DOI: 10.1016/j.ajhg.2016.01.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/19/2016] [Indexed: 12/22/2022] Open
Abstract
Robinow syndrome is a rare congenital disorder characterized by mesomelic limb shortening, genital hypoplasia, and distinctive facial features. Recent reports have identified, in individuals with dominant Robinow syndrome, a specific type of variant characterized by being uniformly located in the penultimate exon of DVL1 and resulting in a -1 frameshift allele with a premature termination codon that escapes nonsense-mediated decay. Here, we studied a cohort of individuals who had been clinically diagnosed with Robinow syndrome but who had not received a molecular diagnosis from variant studies of DVL1, WNT5A, and ROR2. Because of the uniform location of frameshift variants in DVL1-mediated Robinow syndrome and the functional redundancy of DVL1, DVL2, and DVL3, we elected to pursue direct Sanger sequencing of the penultimate exon of DVL1 and its paralogs DVL2 and DVL3 to search for potential disease-associated variants. Remarkably, targeted sequencing identified five unrelated individuals harboring heterozygous, de novo frameshift variants in DVL3, including two splice acceptor mutations and three 1 bp deletions. Similar to the variants observed in DVL1-mediated Robinow syndrome, all variants in DVL3 result in a -1 frameshift, indicating that these highly specific alterations might be a common cause of dominant Robinow syndrome. Here, we review the current knowledge of these peculiar variant alleles in DVL1- and DVL3-mediated Robinow syndrome and further elucidate the phenotypic features present in subjects with DVL1 and DVL3 frameshift mutations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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80
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Sutherland AE. Tissue morphodynamics shaping the early mouse embryo. Semin Cell Dev Biol 2016; 55:89-98. [PMID: 26820524 DOI: 10.1016/j.semcdb.2016.01.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/22/2016] [Indexed: 12/20/2022]
Abstract
Generation of the elongated vertebrate body plan from the initially radially symmetrical embryo requires comprehensive changes to tissue form. These shape changes are generated by specific underlying cell behaviors, coordinated in time and space. Major principles and also specifics are emerging, from studies in many model systems, of the cell and physical biology of how region-specific cell behaviors produce regional tissue morphogenesis, and how these, in turn, are integrated at the level of the embryo. New technical approaches have made it possible more recently, to examine the morphogenesis of the mouse embryo in depth, and to elucidate the underlying cellular mechanisms. This review focuses on recent advances in understanding the cellular basis for the early fundamental events that establish the basic form of the embryo.
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Affiliation(s)
- Ann E Sutherland
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA 22908, United States.
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81
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Jayachandran P, Olmo VN, Sanchez SP, McFarland RJ, Vital E, Werner JM, Hong E, Sanchez-Alberola N, Molodstov A, Brewster RM. Microtubule-associated protein 1b is required for shaping the neural tube. Neural Dev 2016; 11:1. [PMID: 26782621 PMCID: PMC4717579 DOI: 10.1186/s13064-015-0056-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Shaping of the neural tube, the precursor of the brain and spinal cord, involves narrowing and elongation of the neural tissue, concomitantly with other morphogenetic changes that contribue to this process. In zebrafish, medial displacement of neural cells (neural convergence or NC), which drives the infolding and narrowing of the neural ectoderm, is mediated by polarized migration and cell elongation towards the dorsal midline. Failure to undergo proper NC results in severe neural tube defects, yet the molecular underpinnings of this process remain poorly understood. RESULTS We investigated here the role of the microtubule (MT) cytoskeleton in mediating NC in zebrafish embryos using the MT destabilizing and hyperstabilizing drugs nocodazole and paclitaxel respectively. We found that MTs undergo major changes in organization and stability during neurulation and are required for the timely completion of NC by promoting cell elongation and polarity. We next examined the role of Microtubule-associated protein 1B (Map1b), previously shown to promote MT dynamicity in axons. map1b is expressed earlier than previously reported, in the developing neural tube and underlying mesoderm. Loss of Map1b function using morpholinos (MOs) or δMap1b (encoding a truncated Map1b protein product) resulted in delayed NC and duplication of the neural tube, a defect associated with impaired NC. We observed a loss of stable MTs in these embryos that is likely to contribute to the NC defect. Lastly, we found that Map1b mediates cell elongation in a cell autonomous manner and polarized protrusive activity, two cell behaviors that underlie NC and are MT-dependent. CONCLUSIONS Together, these data highlight the importance of MTs in the early morphogenetic movements that shape the neural tube and reveal a novel role for the MT regulator Map1b in mediating cell elongation and polarized cell movement in neural progenitor cells.
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Affiliation(s)
- Pradeepa Jayachandran
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Valerie N Olmo
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Stephanie P Sanchez
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Rebecca J McFarland
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Eudorah Vital
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Jonathan M Werner
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Elim Hong
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA. .,Institut de Biologie Paris Seine-Laboratoire Neuroscience Paris Seine INSERM UMRS 1130, CNRS UMR 8246, UPMC UM 118 Université Pierre et Marie Curie, Paris, France.
| | - Neus Sanchez-Alberola
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Aleksey Molodstov
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Rachel M Brewster
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
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82
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Abstract
Secretion is the cellular process present in every organism that delivers soluble proteins and cargoes to the extracellular space. In eukaryotes, conventional protein secretion (CPS) is the trafficking route that secretory proteins undertake when are transported from the endoplasmic reticulum (ER) to the Golgi apparatus (GA), and subsequently to the plasma membrane (PM) via secretory vesicles or secretory granules. This book chapter recalls the fundamental steps in cell biology research contributing to the elucidation of CPS; it describes the most prominent examples of conventionally secreted proteins in eukaryotic cells and the molecular mechanisms necessary to regulate each step of this process.
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83
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Conte D, Garaffo G, Lo Iacono N, Mantero S, Piccolo S, Cordenonsi M, Perez-Morga D, Orecchia V, Poli V, Merlo GR. The apical ectodermal ridge of the mouse model of ectrodactyly Dlx5;Dlx6-/- shows altered stratification and cell polarity, which are restored by exogenous Wnt5a ligand. Hum Mol Genet 2015; 25:740-54. [PMID: 26685160 PMCID: PMC4743692 DOI: 10.1093/hmg/ddv514] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/10/2015] [Indexed: 02/06/2023] Open
Abstract
The congenital malformation split hand/foot (SHFM) is characterized by missing central fingers and dysmorphology or fusion of the remaining ones. Type-1 SHFM is linked to deletions/rearrangements of the DLX5–DLX6 locus and point mutations in the DLX5 gene. The ectrodactyly phenotype is reproduced in mice by the double knockout (DKO) of Dlx5 and Dlx6. During limb development, the apical ectodermal ridge (AER) is a key-signaling center responsible for early proximal–distal growth and patterning. In Dlx5;6 DKO hindlimbs, the central wedge of the AER loses multilayered organization and shows down-regulation of FGF8 and Dlx2. In search for the mechanism, we examined the non-canonical Wnt signaling, considering that Dwnt-5 is a target of distalless in Drosophila and the knockout of Wnt5, Ryk, Ror2 and Vangl2 in the mouse causes severe limb malformations. We found that in Dlx5;6 DKO limbs, the AER expresses lower levels of Wnt5a, shows scattered β-catenin responsive cells and altered basolateral and planar cell polarity (PCP). The addition of Wnt5a to cultured embryonic limbs restored the expression of AER markers and its stratification. Conversely, the inhibition of the PCP molecule c-jun N-terminal kinase caused a loss of AER marker expression. In vitro, the addition of Wnt5a on mixed primary cultures of embryonic ectoderm and mesenchyme was able to confer re-polarization. We conclude that the Dlx-related ectrodactyly defect is associated with the loss of basoapical and PCP, due to reduced Wnt5a expression and that the restoration of the Wnt5a level is sufficient to partially reverts AER misorganization and dysmorphology.
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Affiliation(s)
- Daniele Conte
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Giulia Garaffo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Nadia Lo Iacono
- Human Genome Department, Istituto Tecnologie Biomediche, CNR Milano, Italy
| | - Stefano Mantero
- Human Genome Department, Istituto Tecnologie Biomediche, CNR Milano, Italy
| | - Stefano Piccolo
- Department of Molecular Medicine, University of Padova, Padova, Italy and
| | | | - David Perez-Morga
- Laboratoire de Parasitologie Moléculaire, IBMM-DBM, Université Libre de Bruxelles, B-6041 Gosselies, Belgium
| | - Valeria Orecchia
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Valeria Poli
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Giorgio R Merlo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy,
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84
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Lei Y, Fathe K, McCartney D, Zhu H, Yang W, Ross ME, Shaw GM, Finnell RH. Rare LRP6 variants identified in spina bifida patients. Hum Mutat 2015; 36:342-9. [PMID: 25546815 DOI: 10.1002/humu.22750] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/17/2014] [Indexed: 12/16/2022]
Abstract
Several single-nucleotide variants (SNVs) in low-density lipoprotein receptor-related protein 6 (Lrp6) cause neural tube defects (NTDs) in mice. We therefore examined LRP6 in 192 unrelated infants from California with the NTD, spina bifida, and found four heterozygous missense SNVs, three of which were predicted to be deleterious, among NTD cases and not in 190 ethnically matched nonmalformed controls. Parents and siblings could not be tested because of the study design. Like Crooked tail and Ringleschwanz mouse variants, the p.Tyr544Cys Lrp6 protein failed to bind the chaperone protein mesoderm development and impaired Lrp6 subcellular localization to the plasma membrane of MDCK II cells. Only the p.Tyr544Cys Lrp6 variant downregulated canonical Wnt signaling in a TopFlash luciferase reporter in vitro assay. In contrast, three Lrp6 mutants (p.Ala3Val, p.Tyr544Cys, and p.Arg1574Leu) increased noncanonical Wnt/planar cell polarity (PCP) signaling in an Ap1-luciferase assay. Thus, LRP6 variants outside of YWTD repeats could potentially predispose embryos to NTDs, whereas Lrp6 modulation of Wnt/PCP signaling would be more essential than its canonical pathway role in neural tube closure.
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Affiliation(s)
- Yunping Lei
- Dell Pediatric Research Institute, Department of Nutritional Sciences, The University of Texas at Austin, Austin, Texas
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85
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Zhang X, Yu X, Jiang G, Miao Y, Wang L, Zhang Y, Liu Y, Fan C, Lin X, Dong Q, Han Q, Zhao H, Han Y, Han X, Rong X, Ding S, Wang E, Wang E. Cytosolic TMEM88 Promotes Invasion and Metastasis in Lung Cancer Cells by Binding DVLS. Cancer Res 2015; 75:4527-37. [PMID: 26359454 DOI: 10.1158/0008-5472.can-14-3828] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 08/15/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Xiupeng Zhang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xinmiao Yu
- Department of Surgical Oncology and Breast Surgery, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Guiyang Jiang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yuan Miao
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Liang Wang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yong Zhang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yang Liu
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Chuifeng Fan
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xuyong Lin
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Qianze Dong
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Qiang Han
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Huanyu Zhao
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yong Han
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xu Han
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xuezhu Rong
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Shuting Ding
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Endi Wang
- Department of Pathology, Duke University Medical Center, Durham, North Carolina
| | - Enhua Wang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China.
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86
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Lee HJ, Shi DL, Zheng JJ. Conformational change of Dishevelled plays a key regulatory role in the Wnt signaling pathways. eLife 2015; 4:e08142. [PMID: 26297804 PMCID: PMC4577825 DOI: 10.7554/elife.08142] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/21/2015] [Indexed: 01/02/2023] Open
Abstract
The intracellular signaling molecule Dishevelled (Dvl) mediates canonical and non-canonical Wnt signaling via its PDZ domain. Different pathways diverge at this point by a mechanism that remains unclear. Here we show that the peptide-binding pocket of the Dvl PDZ domain can be occupied by Dvl's own highly conserved C-terminus, inducing a closed conformation. In Xenopus, Wnt-regulated convergent extension (CE) is readily affected by Dvl mutants unable to form the closed conformation than by wild-type Dvl. We also demonstrate that while Dvl cooperates with other Wnt pathway elements to activate canonical Wnt signaling, the open conformation of Dvl more effectively activates Jun N-terminal kinase (JNK). These results suggest that together with other players in the Wnt signaling pathway, the conformational change of Dvl regulates Wnt stimulated JNK activity in the non-canonical Wnt signaling. DOI:http://dx.doi.org/10.7554/eLife.08142.001 The development of an animal embryo depends on a number of signaling pathways that pass information from the outside of the cell to the inside. These pathways include Wnt signaling, which also regulates cell growth. The pathways must be precisely controlled; abnormal Wnt activity has been implicated in several human diseases, ranging from heart disease to cancer. Wnt signaling is complex, and actually comprises two major pathways: the canonical pathway (which depends on a protein called β-catenin) and the PCP pathway (which doesn't depend on β-catenin). Both pathways are triggered when Wnt molecules bind to receptors on the outside of the cell. These receptors pass the signal into the cell and to a protein called ‘Dishevelled’ (or ‘Dvl’ for short). This protein then passes the signal on through either the canonical or PCP pathway. Nevertheless it is not clear how the Dishevelled protein can direct the signal specifically down either one of these pathways. Lee et al. now show that the Dishevelled protein can take on at least two different shapes. When it is ‘closed’, one end of the protein is tucked inside a pocket elsewhere on the protein's surface. But when Dishevelled is ‘open’, this end of the protein moves out of this pocket. Further experiments using frogs (called Xenopus, which are commonly used in research) reveal that mutant versions of Dishevelled that were unable to take on the closed form strongly affected an aspect of the frog's development that involves the PCP pathway. Lee et al. then demonstrate that while Dishevelled cooperates with several other Wnt pathway components to activate the canonical pathway, the open form of Dishevelled activates the PCP pathway. The next challenge following on from this work is to find out how Wnt molecules binding to the receptor trigger the shape change in Dishevelled. DOI:http://dx.doi.org/10.7554/eLife.08142.002
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Affiliation(s)
- Ho-Jin Lee
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, United States
| | - De-Li Shi
- Laboratoire de biologie du développement, Institut de Biologie Paris-Seine, Sorbonne Universités, Paris, France
| | - Jie J Zheng
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, United States
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87
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Vitorino M, Silva AC, Inácio JM, Ramalho JS, Gur M, Fainsod A, Steinbeisser H, Belo JA. Xenopus Pkdcc1 and Pkdcc2 Are Two New Tyrosine Kinases Involved in the Regulation of JNK Dependent Wnt/PCP Signaling Pathway. PLoS One 2015; 10:e0135504. [PMID: 26270962 PMCID: PMC4536202 DOI: 10.1371/journal.pone.0135504] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 07/22/2015] [Indexed: 12/28/2022] Open
Abstract
Protein Kinase Domain Containing, Cytoplasmic (PKDCC) is a protein kinase which has been implicated in longitudinal bone growth through regulation of chondrocytes formation. Nevertheless, the mechanism by which this occurs remains unknown. Here, we identified two new members of the PKDCC family, Pkdcc1 and Pkdcc2 from Xenopus laevis. Interestingly, our knockdown experiments revealed that these two proteins are both involved on blastopore and neural tube closure during gastrula and neurula stages, respectively. In vertebrates, tissue polarity and cell movement observed during gastrulation and neural tube closure are controlled by Wnt/Planar Cell Polarity (PCP) molecular pathway. Our results showed that Pkdcc1 and Pkdcc2 promote the recruitment of Dvl to the plasma membrane. But surprisingly, they revealed different roles in the induction of a luciferase reporter under the control of Atf2 promoter. While Pkdcc1 induces Atf2 expression, Pkdcc2 does not, and furthermore inhibits its normal induction by Wnt11 and Wnt5a. Altogether our data show, for the first time, that members of the PKDCC family are involved in the regulation of JNK dependent Wnt/PCP signaling pathway.
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Affiliation(s)
- Marta Vitorino
- Regenerative Medicine Program, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro, Portugal
- Center for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| | - Ana Cristina Silva
- Center for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| | - José Manuel Inácio
- Regenerative Medicine Program, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro, Portugal
- Center for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
- CEDOC, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - José Silva Ramalho
- CEDOC, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Michal Gur
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University, P.O. Box 12272, Jerusalem, 91120, Israel
| | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University, P.O. Box 12272, Jerusalem, 91120, Israel
| | | | - José António Belo
- Regenerative Medicine Program, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro, Portugal
- Center for Biomedical Research (CBMR), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
- CEDOC, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
- * E-mail:
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88
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Song JL, Nigam P, Tektas SS, Selva E. microRNA regulation of Wnt signaling pathways in development and disease. Cell Signal 2015; 27:1380-91. [PMID: 25843779 PMCID: PMC4437805 DOI: 10.1016/j.cellsig.2015.03.018] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 03/24/2015] [Accepted: 03/24/2015] [Indexed: 12/19/2022]
Abstract
Wnt signaling pathways and microRNAs (miRNAs) are critical regulators of development. Aberrant Wnt signaling pathways and miRNA levels lead to developmental defects and diverse human pathologies including but not limited to cancer. Wnt signaling pathways regulate a plethora of cellular processes during embryonic development and maintain homeostasis of adult tissues. A majority of Wnt signaling components are regulated by miRNAs which are small noncoding RNAs that are expressed in both animals and plants. In animal cells, miRNAs fine tune gene expression by pairing primarily to the 3'untranslated region of protein coding mRNAs to repress target mRNA translation and/or induce target degradation. miRNA-mediated regulation of signaling transduction pathways is important in modulating dose-sensitive response of cells to signaling molecules. This review discusses components of the Wnt signaling pathways that are regulated by miRNAs in the context of development and diseases. A fundamental understanding of miRNA functions in Wnt signaling transduction pathways may yield new insight into crosstalks of regulatory mechanisms essential for development and disease pathophysiology leading to novel therapeutics.
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Affiliation(s)
- Jia L Song
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
| | - Priya Nigam
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Senel S Tektas
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Erica Selva
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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89
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Sienknecht UJ. Current concepts of hair cell differentiation and planar cell polarity in inner ear sensory organs. Cell Tissue Res 2015; 361:25-32. [PMID: 25959294 DOI: 10.1007/s00441-015-2200-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 04/15/2015] [Indexed: 11/25/2022]
Abstract
Phylogenetically and ontogenetically, vertebrate development led to the generation of several inner ear sensory organs. During embryogenesis, cell fate specification determines whether each progenitor cell differentiates into a sensory hair cell or a supporting cell within the common sensory primordium. Finally, all sensory epithelia of the inner ear consist of a hair cell/supporting cell mosaic, albeit with anatomical differences depending on the sensory organ type. Hair cells develop a polarized bundle of stereovilli that is of functional importance for mechanotransduction. After initiating stereovillar development, hair cells align their bundles in a coordinated fashion, generating a characteristic hair cell orientation pattern, a process referred to as planar cell polarity (PCP). The pathway that controls PCP in the inner ear needs both to establish the development of a polarized morphology of the stereovillar bundle of the hair cell and to organize a systematic hair cell alignment. Because the hair cell orientation patterns of the various inner ear organs and vertebrate species differ fundamentally, it becomes apparent that in vertebrates, different aspects of PCP need to be independently controlled. In spite of important progress recently gained in the field of PCP research, we still need to identify the mechanisms (1) that initiate molecular asymmetries in cells, (2) that guide the transmission of polarity information from cell to cell, and (3) that consistently translate such polarity information into morphological asymmetries of hair cells.
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Affiliation(s)
- Ulrike J Sienknecht
- Department of Neuroscience, School of Medicine and Health Science, Research Center Neurosensory Science, Cluster of Excellence "Hearing4all", Carl von Ossietzky University Oldenburg, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany,
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90
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Andre P, Song H, Kim W, Kispert A, Yang Y. Wnt5a and Wnt11 regulate mammalian anterior-posterior axis elongation. Development 2015; 142:1516-27. [PMID: 25813538 DOI: 10.1242/dev.119065] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/04/2015] [Indexed: 01/01/2023]
Abstract
Mesoderm formation and subsequent anterior-posterior (A-P) axis elongation are fundamental aspects of gastrulation, which is initiated by formation of the primitive streak (PS). Convergent extension (CE) movements and epithelial-mesenchymal transition (EMT) are important for A-P axis elongation in vertebrate embryos. The evolutionarily conserved planar cell polarity (PCP) pathway regulates CE, and Wnts regulate many aspects of gastrulation including CE and EMT. However, the Wnt ligands that regulate A-P axis elongation in mammalian development remain unknown. Wnt11 and Wnt5a regulate axis elongation in lower vertebrates, but only Wnt5a, not Wnt11, regulates mammalian PCP signaling and A-P axis elongation in development. Here, by generating Wnt5a; Wnt11 compound mutants, we show that Wnt11 and Wnt5a play redundant roles during mouse A-P axis elongation. Both genes regulate trunk notochord extension through PCP-controlled CE of notochord cells, establishing a role for Wnt11 in mammalian PCP. We show that Wnt5a and Wnt11 are required for proper patterning of the neural tube and somites by regulating notochord formation, and provide evidence that both genes are required for the generation and migration of axial and paraxial mesodermal precursor cells by regulating EMT. Axial and paraxial mesodermal precursors ectopically accumulate in the PS at late gastrula stages in Wnt5a(-/-); Wnt11(-/-) embryos and these cells ectopically express epithelial cell adhesion molecules. Our data suggest that Wnt5a and Wnt11 regulate EMT by inducing p38 (Mapk14) phosphorylation. Our findings provide new insights into the role of Wnt5a and Wnt11 in mouse early development and also in cancer metastasis, during which EMT plays a crucial role.
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Affiliation(s)
- Philipp Andre
- Genetic Disease Research Branch, National Human Genome Research Institute, Bethesda, MD 20814, USA
| | - Hai Song
- Genetic Disease Research Branch, National Human Genome Research Institute, Bethesda, MD 20814, USA
| | - Wantae Kim
- Genetic Disease Research Branch, National Human Genome Research Institute, Bethesda, MD 20814, USA
| | - Andreas Kispert
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover D-30625, Germany
| | - Yingzi Yang
- Genetic Disease Research Branch, National Human Genome Research Institute, Bethesda, MD 20814, USA Department of Developmental Biology, Harvard School of Dental Medicine, 188 Longwood Ave., Boston, MA 02115, USA
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91
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McGreevy EM, Vijayraghavan D, Davidson LA, Hildebrand JD. Shroom3 functions downstream of planar cell polarity to regulate myosin II distribution and cellular organization during neural tube closure. Biol Open 2015; 4:186-96. [PMID: 25596276 PMCID: PMC4365487 DOI: 10.1242/bio.20149589] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Neural tube closure is a critical developmental event that relies on actomyosin contractility to facilitate specific processes such as apical constriction, tissue bending, and directional cell rearrangements. These complicated processes require the coordinated activities of Rho-Kinase (Rock), to regulate cytoskeletal dynamics and actomyosin contractility, and the Planar Cell Polarity (PCP) pathway, to direct the polarized cellular behaviors that drive convergent extension (CE) movements. Here we investigate the role of Shroom3 as a direct linker between PCP and actomyosin contractility during mouse neural tube morphogenesis. In embryos, simultaneous depletion of Shroom3 and the PCP components Vangl2 or Wnt5a results in an increased liability to NTDs and CE failure. We further show that these pathways intersect at Dishevelled, as Shroom3 and Dishevelled 2 co-distribute and form a physical complex in cells. We observed that multiple components of the Shroom3 pathway are planar polarized along mediolateral cell junctions in the neural plate of E8.5 embryos in a Shroom3 and PCP-dependent manner. Finally, we demonstrate that Shroom3 mutant embryos exhibit defects in planar cell arrangement during neural tube closure, suggesting a role for Shroom3 activity in CE. These findings support a model in which the Shroom3 and PCP pathways interact to control CE and polarized bending of the neural plate and provide a clear illustration of the complex genetic basis of NTDs.
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Affiliation(s)
- Erica M McGreevy
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | - Lance A Davidson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jeffrey D Hildebrand
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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92
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Gentzel M, Schille C, Rauschenberger V, Schambony A. Distinct functionality of dishevelled isoforms on Ca2+/calmodulin-dependent protein kinase 2 (CamKII) in Xenopus gastrulation. Mol Biol Cell 2015; 26:966-77. [PMID: 25568338 PMCID: PMC4342031 DOI: 10.1091/mbc.e14-06-1089] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
CamKII is a novel binding partner of Arrb2/Dvl2 protein complexes and is required for convergent extension movements in Xenopus. CamKII physically and functionally interacts with Dvl2, whereas CamKII activity is antagonistically modulated by Dvl1 and Dvl3. Wnt ligands trigger the activation of a variety of β-catenin–dependent and β-catenin–independent intracellular signaling cascades. Despite the variations in intracellular signaling, Wnt pathways share the effector proteins frizzled, dishevelled, and β-arrestin. It is unclear how the specific activation of individual branches and the integration of multiple signals are achieved. We hypothesized that the composition of dishevelled–β-arrestin protein complexes contributes to signal specificity and identified CamKII as an interaction partner of the dishevelled–β-arrestin protein complex by quantitative functional proteomics. Specifically, we found that CamKII isoforms interact differentially with the three vertebrate dishevelled proteins. Dvl1 is required for the activation of CamKII and PKC in the Wnt/Ca2+ pathway. However, CamKII interacts with Dvl2 but not with Dvl1, and Dvl2 is necessary to mediate CamKII function downstream of Dvl1 in convergent extension movements in Xenopus gastrulation. Our findings indicate that the different Dvl proteins and the composition of dishevelled–β-arrestin protein complexes contribute to the specific activation of individual branches of Wnt signaling.
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Affiliation(s)
- Marc Gentzel
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Carolin Schille
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Verena Rauschenberger
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Alexandra Schambony
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
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93
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Abstract
Planar cell polarity (PCP) refers to the coordinated alignment of cell polarity across the tissue plane. Key to the establishment of PCP is asymmetric partitioning of cortical PCP components and intercellular communication to coordinate polarity between neighboring cells. Recent progress has been made toward understanding how protein transport, endocytosis, and intercellular interactions contribute to asymmetric PCP protein localization. Additionally, the functions of gradients and mechanical forces as global cues that bias PCP orientation are beginning to be elucidated. Together, these findings are shedding light on how global cues integrate with local cell interactions to organize cellular polarity at the tissue level.
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Affiliation(s)
- Danelle Devenport
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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94
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Sinha T, Lin L, Li D, Davis J, Evans S, Wynshaw-Boris A, Wang J. Mapping the dynamic expression of Wnt11 and the lineage contribution of Wnt11-expressing cells during early mouse development. Dev Biol 2014; 398:177-92. [PMID: 25448697 DOI: 10.1016/j.ydbio.2014.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/06/2014] [Accepted: 11/11/2014] [Indexed: 12/31/2022]
Abstract
Planar cell polarity (PCP) signaling is an evolutionarily conserved mechanism that coordinates polarized cell behavior to regulate tissue morphogenesis during vertebrate gastrulation, neurulation and organogenesis. In Xenopus and zebrafish, PCP signaling is activated by non-canonical Wnts such as Wnt11, and detailed understanding of Wnt11 expression has provided important clues on when, where and how PCP may be activated to regulate tissue morphogenesis. To explore the role of Wnt11 in mammalian development, we established a Wnt11 expression and lineage map with high spatial and temporal resolution by creating and analyzing a tamoxifen-inducible Wnt11-CreER BAC (bacterial artificial chromosome) transgenic mouse line. Our short- and long-term lineage tracing experiments indicated that Wnt11-CreER could faithfully recapitulate endogenous Wnt11 expression, and revealed for the first time that cells transiently expressing Wnt11 at early gastrulation were fated to become specifically the progenitors of the entire endoderm. During mid-gastrulation, Wnt11-CreER expressing cells also contribute extensively to the endothelium in both embryonic and extraembryonic compartments, and the endocardium in all chambers of the developing heart. In contrast, Wnt11-CreER expression in the myocardium starts from late-gastrulation, and occurs in three transient, sequential waves: first in the precursors of the left ventricular (LV) myocardium from E7.0 to 8.0; subsequently in the right ventricular (RV) myocardium from E8.0 to 9.0; and finally in the superior wall of the outflow tract (OFT) myocardium from E8.5 to 10.5. These results provide formal genetic proof that the majority of the endocardium and myocardium diverge by mid-gastrulation in the mouse, and suggest a tight spatial and temporal control of Wnt11 expression in the myocardial lineage to coordinate with myocardial differentiation in the first and second heart field progenitors to form the LV, RV and OFT. The insights gained from this study will also guide future investigations to decipher the role of non-canonical Wnt/PCP signaling in endoderm development, vasculogenesis and heart formation.
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Affiliation(s)
- Tanvi Sinha
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, United States
| | - Lizhu Lin
- Skaggs School of Pharmacy and Pharmaceutical Sciences & Department of Medicine, University of California, San Diego, United States
| | - Ding Li
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, United States
| | - Jennifer Davis
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, United States
| | - Sylvia Evans
- Skaggs School of Pharmacy and Pharmaceutical Sciences & Department of Medicine, University of California, San Diego, United States
| | - Anthony Wynshaw-Boris
- Department of Genetics, School of Medicine, Case Western Reserve University, United States
| | - Jianbo Wang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, United States.
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95
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Sinha T, Li D, Théveniau-Ruissy M, Hutson MR, Kelly RG, Wang J. Loss of Wnt5a disrupts second heart field cell deployment and may contribute to OFT malformations in DiGeorge syndrome. Hum Mol Genet 2014; 24:1704-16. [PMID: 25410658 DOI: 10.1093/hmg/ddu584] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Outflow tract (OFT) malformation accounts for ∼30% of human congenital heart defects and manifests frequently in TBX1 haplo-insufficiency associated DiGeorge (22q11.2 deletion) syndrome. OFT myocardium originates from second heart field (SHF) progenitors in the pharyngeal and splanchnic mesoderm (SpM), but how these progenitors are deployed to the OFT is unclear. We find that SHF progenitors in the SpM gradually gain epithelial character and are deployed to the OFT as a cohesive sheet. Wnt5a, a non-canonical Wnt, is expressed specifically in the caudal SpM and may regulate oriented cell intercalation to incorporate SHF progenitors into an epithelial-like sheet, thereby generating the pushing force to deploy SHF cells rostrally into the OFT. Using enhancer trap and Cre transgenes, our lineage tracing experiments show that in Wnt5a null mice, SHF progenitors are trapped in the SpM and fail to be deployed to the OFT efficiently, resulting in a reduction in the inferior OFT myocardial wall and its derivative, subpulmonary myocardium. Concomitantly, the superior OFT and subaortic myocardium are expanded. Finally, in chick embryos, blocking the Wnt5a function in the caudal SpM perturbs polarized elongation of SHF progenitors, and compromises their deployment to the OFT. Collectively, our results highlight a critical role for Wnt5a in deploying SHF progenitors from the SpM to the OFT. Given that Wnt5a is a putative transcriptional target of Tbx1, and the similar reduction of subpulmonary myocardium in Tbx1 mutant mice, our results suggest that perturbing Wnt5a-mediated SHF deployment may be an important pathogenic mechanism contributing to OFT malformations in DiGeorge syndrome.
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Affiliation(s)
- Tanvi Sinha
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Alabama, USA
| | - Ding Li
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Alabama, USA
| | | | - Mary R Hutson
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina
| | - Robert G Kelly
- Aix Marseille Université, CNRS, IBDM UMR 7288, Marseille 13288, France
| | - Jianbo Wang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Alabama, USA,
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96
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Hatakeyama J, Wald JH, Printsev I, Ho HYH, Carraway KL. Vangl1 and Vangl2: planar cell polarity components with a developing role in cancer. Endocr Relat Cancer 2014; 21:R345-56. [PMID: 24981109 PMCID: PMC4332879 DOI: 10.1530/erc-14-0141] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cancers commonly reactivate embryonic developmental pathways to promote the aggressive behavior of their cells, resulting in metastasis and poor patient outcome. While developmental pathways such as canonical Wnt signaling and epithelial-to-mesenchymal transition have received much attention, our understanding of the role of the planar cell polarity (PCP) pathway in tumor progression remains rudimentary. Protein components of PCP, including a subset that overlaps with the canonical Wnt pathway, partition in polarized epithelial cells along the planar axis and are required for the establishment and maintenance of lateral epithelial polarity. Significant insight into PCP regulation of developmental and cellular processes has come from analysis of the functions of the core PCP scaffolding proteins Vangl1 and Vangl2. In particular, studies on zebrafish and with Looptail (Lp) mice, which harbor point mutations in Vangl2 that alter its trafficking and localization, point to roles for the PCP pathway in maintaining cell polarization along both the apical-basal and planar axes as well as in collective cell motility and invasiveness. Recent findings have suggested that the Vangls can promote similar processes in tumor cells. Initial data-mining efforts suggest that VANGL1 and VANGL2 are dysregulated in human cancers, and estrogen receptor (ER)-positive breast cancer patients whose tumors exhibit elevated VANGL1 expression suffer from shortened overall survival. Overall, evidence is beginning to accumulate that the heightened cellular motility and invasiveness associated with PCP reactivation may contribute to the malignancy of some cancer subtypes.
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Affiliation(s)
- Jason Hatakeyama
- Department of Biochemistry and Molecular MedicineUC Davis School of Medicine, UC Davis Comprehensive Cancer Center, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, California 95817, USADepartment of Cell Biology and Human AnatomyUC Davis School of Medicine, Davis, California 95616, USA
| | - Jessica H Wald
- Department of Biochemistry and Molecular MedicineUC Davis School of Medicine, UC Davis Comprehensive Cancer Center, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, California 95817, USADepartment of Cell Biology and Human AnatomyUC Davis School of Medicine, Davis, California 95616, USA
| | - Ignat Printsev
- Department of Biochemistry and Molecular MedicineUC Davis School of Medicine, UC Davis Comprehensive Cancer Center, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, California 95817, USADepartment of Cell Biology and Human AnatomyUC Davis School of Medicine, Davis, California 95616, USA
| | - Hsin-Yi Henry Ho
- Department of Biochemistry and Molecular MedicineUC Davis School of Medicine, UC Davis Comprehensive Cancer Center, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, California 95817, USADepartment of Cell Biology and Human AnatomyUC Davis School of Medicine, Davis, California 95616, USA
| | - Kermit L Carraway
- Department of Biochemistry and Molecular MedicineUC Davis School of Medicine, UC Davis Comprehensive Cancer Center, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, California 95817, USADepartment of Cell Biology and Human AnatomyUC Davis School of Medicine, Davis, California 95616, USA
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97
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Jones C, Qian D, Kim SM, Li S, Ren D, Knapp L, Sprinzak D, Avraham KB, Matsuzaki F, Chi F, Chen P. Ankrd6 is a mammalian functional homolog of Drosophila planar cell polarity gene diego and regulates coordinated cellular orientation in the mouse inner ear. Dev Biol 2014; 395:62-72. [PMID: 25218921 DOI: 10.1016/j.ydbio.2014.08.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/21/2014] [Accepted: 08/22/2014] [Indexed: 01/23/2023]
Abstract
The coordinated polarization of neighboring cells within the plane of the tissue, known as planar cell polarity (PCP), is a recurring theme in biology. It is required for numerous developmental processes for the form and function of many tissues and organs across species. The genetic pathway regulating PCP was first discovered in Drosophila, and an analogous but distinct pathway is emerging in vertebrates. It consists of membrane protein complexes known as core PCP proteins that are conserved across species. Here we report that the over-expression of the murine Ankrd6 (mAnkrd6) gene that shares homology with Drosophila core PCP gene diego causes a typical PCP phenotype in Drosophila, and mAnkrd6 can rescue the loss of function of diego in Drosophila. In mice, mAnkrd6 protein is asymmetrically localized in cells of the inner ear sensory organs, characteristic of components of conserved core PCP complexes. The loss of mAnkrd6 causes PCP defects in the inner ear sensory organs. Moreover, canonical Wnt signaling is significantly increased in mouse embryonic fibroblasts from mAnkrd6 knockout mice in comparison to wild type controls. Together, these results indicated that mAnkrd6 is a functional homolog of the Drosophila diego gene for mammalian PCP regulation and act to suppress canonical Wnt signaling.
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Affiliation(s)
- Chonnettia Jones
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
| | - Dong Qian
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Sun Myoung Kim
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Shuangding Li
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Dongdong Ren
- Department of Otolaryngology, Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, China
| | - Lindsey Knapp
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - David Sprinzak
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Tel Aviv, Israel
| | - Fumio Matsuzaki
- Laboratory of Cell Asymmetry, Center for Developmental Biology, Riken, Kobe, Japan
| | - Fanglu Chi
- Department of Otolaryngology, Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, China
| | - Ping Chen
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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98
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Merello E, Mascelli S, Raso A, Piatelli G, Consales A, Cama A, Kibar Z, Capra V, Marco PD. Expanding the mutational spectrum associated to neural tube defects: literature revision and description of novel VANGL1 mutations. ACTA ACUST UNITED AC 2014; 103:51-61. [PMID: 25208524 DOI: 10.1002/bdra.23305] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/30/2014] [Accepted: 08/11/2014] [Indexed: 12/23/2022]
Abstract
BACKGROUND Neural Tube Defects (NTD) are a common class of birth defects that occur in approximately 1 in 1000 live births. Both genetic and nongenetic factors are involved in the etiology of NTD. Planar cell polarity (PCP) genes plays a critical role in neural tube closure in model organisms. Studies in humans have identified nonsynonymous mutations in PCP pathway genes, including the VANGL genes, that may play a role as risk factors for NTD. METHODS Here, we present the results of VANGL1 and VANGL2 mutational screening in a series of 53 NTD patients and 27 couples with a previous NTD affected pregnancy. RESULTS We identified three heterozygous missense variants in VANGL1, p.Ala187Val, p.Asp389His, and p.Arg517His, that are absent in controls and predicted to be detrimental on the protein function and, thus, we expanded the mutational spectrum of VANGL1 in NTD cases. We did not identify any new variants having an evident pathogenic effect on protein function in VANGL2. Moreover, we reviewed all the rare nonsynonymous or synonymous variants of VANGL1 and VANGL2 found in patients and controls so far published and re-evaluated them for their pathogenic role by in silico prediction tools. Association tests were performed to demonstrate the enrichment of deleterious variants in reviewed cases versus controls from Exome Variant Server (EVS). CONCLUSION We showed a significant (p = 7.0E-5) association between VANGL1 rare genetic variants, especially missense mutations, and NTDs risk.
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Affiliation(s)
- E Merello
- Istituto Giannina Gaslini, Genova, Italy
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99
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Shangguan S, Wang L, Chang S, Lu X, Wang Z, Wu L, Wang J, Wang X, Guan Z, Bao Y, Zhao H, Zou J, Niu B, Zhang T. DNA methylation aberrations rather than polymorphisms ofFZD3gene increase the risk of spina bifida in a high-risk region for neural tube defects. ACTA ACUST UNITED AC 2014; 103:37-44. [DOI: 10.1002/bdra.23285] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/15/2014] [Accepted: 06/23/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Shaofang Shangguan
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Li Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Shaoyan Chang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Xiaoling Lu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Zhen Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Lihua Wu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Jianhua Wang
- Department of Biotechnology; Capital Institute of Pediatrics; Beijing China
| | - Xiuwei Wang
- Department of Biotechnology; Capital Institute of Pediatrics; Beijing China
| | - Zhen Guan
- Department of Biotechnology; Capital Institute of Pediatrics; Beijing China
| | - Yihua Bao
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Huizhi Zhao
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
| | - Jizhen Zou
- Department of Pathology; Capital Institute of Pediatrics; Beijing China
| | - Bo Niu
- Department of Biotechnology; Capital Institute of Pediatrics; Beijing China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics; Capital Institute of Pediatrics; Beijing China
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100
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Murdoch JN, Damrau C, Paudyal A, Bogani D, Wells S, Greene NDE, Stanier P, Copp AJ. Genetic interactions between planar cell polarity genes cause diverse neural tube defects in mice. Dis Model Mech 2014; 7:1153-63. [PMID: 25128525 PMCID: PMC4174526 DOI: 10.1242/dmm.016758] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Neural tube defects (NTDs) are among the commonest and most severe forms of developmental defect, characterized by disruption of the early embryonic events of central nervous system formation. NTDs have long been known to exhibit a strong genetic dependence, yet the identity of the genetic determinants remains largely undiscovered. Initiation of neural tube closure is disrupted in mice homozygous for mutations in planar cell polarity (PCP) pathway genes, providing a strong link between NTDs and PCP signaling. Recently, missense gene variants have been identified in PCP genes in humans with NTDs, although the range of phenotypes is greater than in the mouse mutants. In addition, the sequence variants detected in affected humans are heterozygous, and can often be detected in unaffected individuals. It has been suggested that interactions between multiple heterozygous gene mutations cause the NTDs in humans. To determine the phenotypes produced in double heterozygotes, we bred mice with all three pairwise combinations of Vangl2(Lp), Scrib(Crc) and Celsr1(Crsh) mutations, the most intensively studied PCP mutants. The majority of double-mutant embryos had open NTDs, with the range of phenotypes including anencephaly and spina bifida, therefore reflecting the defects observed in humans. Strikingly, even on a uniform genetic background, variability in the penetrance and severity of the mutant phenotypes was observed between the different double-heterozygote combinations. Phenotypically, Celsr1(Crsh);Vangl2(Lp);Scrib(Crc) triply heterozygous mutants were no more severe than doubly heterozygous or singly homozygous mutants. We propose that some of the variation between double-mutant phenotypes could be attributed to the nature of the protein disruption in each allele: whereas Scrib(Crc) is a null mutant and produces no Scrib protein, Celsr1(Crsh) and Vangl2(Lp) homozygotes both express mutant proteins, consistent with dominant effects. The variable outcomes of these genetic interactions are of direct relevance to human patients and emphasize the importance of performing comprehensive genetic screens in humans.
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Affiliation(s)
- Jennifer N Murdoch
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, TW20 0RD, UK. MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK.
| | - Christine Damrau
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
| | - Anju Paudyal
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
| | - Debora Bogani
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
| | - Sara Wells
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
| | - Nicholas D E Greene
- Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Philip Stanier
- Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Andrew J Copp
- Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
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