151
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Huang H, Kornberg TB. Myoblast cytonemes mediate Wg signaling from the wing imaginal disc and Delta-Notch signaling to the air sac primordium. eLife 2015; 4:e06114. [PMID: 25951303 PMCID: PMC4423120 DOI: 10.7554/elife.06114] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/16/2015] [Indexed: 12/17/2022] Open
Abstract
The flight muscles, dorsal air sacs, wing blades, and thoracic cuticle of the Drosophila adult function in concert, and their progenitor cells develop together in the wing imaginal disc. The wing disc orchestrates dorsal air sac development by producing decapentaplegic and fibroblast growth factor that travel via specific cytonemes in order to signal to the air sac primordium (ASP). Here, we report that cytonemes also link flight muscle progenitors (myoblasts) to disc cells and to the ASP, enabling myoblasts to relay signaling between the disc and the ASP. Frizzled (Fz)-containing myoblast cytonemes take up Wingless (Wg) from the disc, and Delta (Dl)-containing myoblast cytonemes contribute to Notch activation in the ASP. Wg signaling negatively regulates Dl expression in the myoblasts. These results reveal an essential role for cytonemes in Wg and Notch signaling and for a signal relay system in the myoblasts.
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Affiliation(s)
- Hai Huang
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
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152
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Chen CC, Wang L, Plikus MV, Jiang TX, Murray PJ, Ramos R, Guerrero-Juarez CF, Hughes MW, Lee OK, Shi S, Widelitz RB, Lander AD, Chuong CM. Organ-level quorum sensing directs regeneration in hair stem cell populations. Cell 2015; 161:277-90. [PMID: 25860610 PMCID: PMC4393531 DOI: 10.1016/j.cell.2015.02.016] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 01/12/2015] [Accepted: 02/02/2015] [Indexed: 11/18/2022]
Abstract
Coordinated organ behavior is crucial for an effective response to environmental stimuli. By studying regeneration of hair follicles in response to patterned hair plucking, we demonstrate that organ-level quorum sensing allows coordinated responses to skin injury. Plucking hair at different densities leads to a regeneration of up to five times more neighboring, unplucked resting hairs, indicating activation of a collective decision-making process. Through data modeling, the range of the quorum signal was estimated to be on the order of 1 mm, greater than expected for a diffusible molecular cue. Molecular and genetic analysis uncovered a two-step mechanism, where release of CCL2 from injured hairs leads to recruitment of TNF-α-secreting macrophages, which accumulate and signal to both plucked and unplucked follicles. By coupling immune response with regeneration, this mechanism allows skin to respond predictively to distress, disregarding mild injury, while meeting stronger injury with full-scale cooperative activation of stem cells.
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Affiliation(s)
- Chih-Chiang Chen
- Department of Pathology, University of Southern California, Los Angeles, CA 90033, USA; Department of Dermatology, Taipei Veterans General Hospital, Taipei 112, Taiwan, ROC; Institute of Clinical Medicine and Department of Dermatology, National Yang-Ming University, Taipei, Taiwan 112, ROC
| | - Lei Wang
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Maksim V Plikus
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California Irvine, Irvine, CA 92697, USA
| | - Ting Xin Jiang
- Department of Pathology, University of Southern California, Los Angeles, CA 90033, USA
| | - Philip J Murray
- Division of Mathematics, University of Dundee, Dundee DD1 4HN, UK
| | - Raul Ramos
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California Irvine, Irvine, CA 92697, USA
| | - Christian F Guerrero-Juarez
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California Irvine, Irvine, CA 92697, USA
| | - Michael W Hughes
- International Laboratory of Wound Repair and Regeneration and Institute of Clinical Medicine, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Oscar K Lee
- Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei and Center for Stem Cell Research, National Yang-Ming University and Veterans General Hospital, Taipei 112, Taiwan, ROC
| | - Songtao Shi
- Department of Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA 19104, USA
| | - Randall B Widelitz
- Department of Pathology, University of Southern California, Los Angeles, CA 90033, USA
| | - Arthur D Lander
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California Irvine, Irvine, CA 92697, USA; Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Cheng Ming Chuong
- Department of Pathology, University of Southern California, Los Angeles, CA 90033, USA; Institute of Clinical Medicine and Department of Dermatology, National Yang-Ming University, Taipei, Taiwan 112, ROC; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei 10617, Taiwan.
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153
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López JL, Soler J. Mathematics and Biology: a round trip: comment on "On the interplay between mathematics and biology, hallmarks toward a new systems biology" by N. Bellomo et al. Phys Life Rev 2015; 12:78-80. [PMID: 25623963 DOI: 10.1016/j.plrev.2015.01.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 11/16/2022]
Affiliation(s)
- José Luis López
- University of Granada, Departamento de Matemática Aplicada, 18071 Granada, Spain
| | - Juan Soler
- University of Granada, Departamento de Matemática Aplicada, 18071 Granada, Spain.
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154
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D'Angelo G, Matusek T, Pizette S, Thérond PP. Endocytosis of Hedgehog through dispatched regulates long-range signaling. Dev Cell 2015; 32:290-303. [PMID: 25619925 DOI: 10.1016/j.devcel.2014.12.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 09/22/2014] [Accepted: 12/01/2014] [Indexed: 01/20/2023]
Abstract
The proteins of the Hedgehog (Hh) family are secreted proteins exerting short- and long-range control over various cell fates in developmental patterning. The Hh gradient in Drosophila wing imaginal discs consists of apical and basolateral secreted pools, but the mechanisms governing the overall establishment of the gradient remain unclear. We investigated the relative contributions of endocytosis and recycling to control the Hh gradient. We show that, upon its initial apical secretion, Hh is re-internalized. We examined the effect of the resistance-nodulation-division transporter Dispatched (Disp) on long-range Hh signaling and unexpectedly found that Disp is specifically required for apical endocytosis of Hh. Re-internalized Hh is then regulated in a Rab5- and Rab4-dependent manner to ensure its long-range activity. We propose that Hh-producing cells integrate endocytosis and recycling as two instrumental mechanisms contributing to regulate the long-range activity of Hh.
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Affiliation(s)
- Gisela D'Angelo
- Institut de Biologie de Valrose - iBV, Centre de Biochimie, Université Nice Sophia Antipolis, CNRS UMR7277, INSERM 1091, Parc Valrose, 06108 Nice Cedex 2, France.
| | - Tamás Matusek
- Institut de Biologie de Valrose - iBV, Centre de Biochimie, Université Nice Sophia Antipolis, CNRS UMR7277, INSERM 1091, Parc Valrose, 06108 Nice Cedex 2, France
| | - Sandrine Pizette
- Institut de Biologie de Valrose - iBV, Centre de Biochimie, Université Nice Sophia Antipolis, CNRS UMR7277, INSERM 1091, Parc Valrose, 06108 Nice Cedex 2, France
| | - Pascal P Thérond
- Institut de Biologie de Valrose - iBV, Centre de Biochimie, Université Nice Sophia Antipolis, CNRS UMR7277, INSERM 1091, Parc Valrose, 06108 Nice Cedex 2, France.
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155
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The ESCRT machinery regulates the secretion and long-range activity of Hedgehog. Nature 2015; 516:99-103. [PMID: 25471885 DOI: 10.1038/nature13847] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 09/08/2014] [Indexed: 01/10/2023]
Abstract
The conserved family of Hedgehog (Hh) proteins acts as short- and long-range secreted morphogens, controlling tissue patterning and differentiation during embryonic development. Mature Hh carries hydrophobic palmitic acid and cholesterol modifications essential for its extracellular spreading. Various extracellular transportation mechanisms for Hh have been suggested, but the pathways actually used for Hh secretion and transport in vivo remain unclear. Here we show that Hh secretion in Drosophila wing imaginal discs is dependent on the endosomal sorting complex required for transport (ESCRT). In vivo the reduction of ESCRT activity in cells producing Hh leads to a retention of Hh at the external cell surface. Furthermore, we show that ESCRT activity in Hh-producing cells is required for long-range signalling. We also provide evidence that pools of Hh and ESCRT proteins are secreted together into the extracellular space in vivo and can subsequently be detected together at the surface of receiving cells. These findings uncover a new function for ESCRT proteins in controlling morphogen activity and reveal a new mechanism for the transport of secreted Hh across the tissue by extracellular vesicles, which is necessary for long-range target induction.
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156
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Akiyama T, Gibson MC. Morphogen transport: theoretical and experimental controversies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:99-112. [PMID: 25581550 DOI: 10.1002/wdev.167] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 10/13/2014] [Indexed: 01/09/2023]
Abstract
UNLABELLED According to morphogen gradient theory, extracellular ligands produced from a localized source convey positional information to receiving cells by signaling in a concentration-dependent manner. How do morphogens create concentration gradients to establish positional information in developing tissues? Surprisingly, the answer to this central question remains largely unknown. During development, a relatively small number of morphogens are reiteratively deployed to ensure normal embryogenesis and organogenesis. Thus, the intracellular processing and extracellular transport of morphogens are tightly regulated in a tissue-specific manner. Over the past few decades, diverse experimental and theoretical approaches have led to numerous conflicting models for gradient formation. In this review, we summarize the experimental evidence for each model and discuss potential future directions for studies of morphogen gradients. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.
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Affiliation(s)
- Takuya Akiyama
- Stowers Institute for Medical Research, Kansas City, MO, USA
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157
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Seijo-Barandiarán I, Guerrero I, Bischoff M. In Vivo Imaging of Hedgehog Transport in Drosophila Epithelia. Methods Mol Biol 2015; 1322:9-18. [PMID: 26179035 DOI: 10.1007/978-1-4939-2772-2_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Hedgehog (Hh) signaling pathway is a regulator of patterning, cell migration and axon guidance during development as well as of homeostatic events in adult organs. It is highly conserved from Drosophila to humans. In many contexts during development, Hh appears to function as a morphogen; it spreads from producing cells to trigger concentration dependent responses in target cells, leading to their specification. During production, Hh undergoes two lipid modifications resulting in a highly hydrophobic molecule. The processes that create lipid-modified Hh for release from producing cells and that move it to target cells in a graded manner are complex. While most of the work done trying to explain Hh gradient formation is based on immunohistochemical studies in steady state, in vivo imaging in intact organisms is the finest technique to study gradient formation in real time. Both the wing imaginal disc epithelium and the adult abdominal epidermis of Drosophila are well suited for in vivo imaging. They allow us to observe the behavior of cells and fluorescently labeled proteins, without interfering with development. Here, we describe in vivo imaging methods for these two epithelia, which allowed us to study Hh transport along specialized cytoplasmic protrusions called cytonemes.
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Affiliation(s)
- Irene Seijo-Barandiarán
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Nicolas Cabrera 1, Cantoblanco, Madrid, 28049, Spain
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158
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Abstract
Recent findings in several organ systems show that cytoneme-mediated signaling transports signaling proteins along cellular extensions and targets cell-to-cell exchanges to synaptic contacts. This mechanism of paracrine signaling may be a general one that is used by many (or all) cell types in many (or all) organs. We briefly review these findings in this perspective. We also describe the properties of several signaling systems that have previously been interpreted to support a passive diffusion mechanism of signaling protein dispersion, but can now be understood in the context of the cytoneme mechanism. Also watch the Video Abstract.
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Affiliation(s)
- Sougata Roy
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Thomas B. Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
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159
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Vyas N, Walvekar A, Tate D, Lakshmanan V, Bansal D, Lo Cicero A, Raposo G, Palakodeti D, Dhawan J. Vertebrate Hedgehog is secreted on two types of extracellular vesicles with different signaling properties. Sci Rep 2014; 4:7357. [PMID: 25483805 PMCID: PMC4258658 DOI: 10.1038/srep07357] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 11/18/2014] [Indexed: 12/29/2022] Open
Abstract
Hedgehog (Hh) is a secreted morphogen that elicits differentiation and patterning in developing tissues. Multiple proposed mechanisms to regulate Hh dispersion includes lipoprotein particles and exosomes. Here we report that vertebrate Sonic Hedgehog (Shh) is secreted on two types of extracellular-vesicles/exosomes, from human cell lines and primary chick notochord cells. Although largely overlapping in size as estimated from electron micrographs, the two exosomal fractions exhibited distinct protein and RNA composition. We have probed the functional properties of these vesicles using cell-based assays of Hh-elicited gene expression. Our results suggest that while both Shh-containing exo-vesicular fractions can activate an ectopic Gli-luciferase construct, only exosomes co-expressing Integrins can activate endogenous Shh target genes HNF3β and Olig2 during the differentiation of mouse ES cells to ventral neuronal progenitors. Taken together, our results demonstrate that primary vertebrate cells secrete Shh in distinct vesicular forms, and support a model where packaging of Shh along with other signaling proteins such as Integrins on exosomes modulates target gene activation. The existence of distinct classes of Shh-containing exosomes also suggests a previously unappreciated complexity for fine-tuning of Shh-mediated gradients and pattern formation.
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Affiliation(s)
- Neha Vyas
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Ankita Walvekar
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Dhananjay Tate
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | | | - Dhiru Bansal
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Alessandra Lo Cicero
- 1] Institut Curie, UMR 144, CNRS, F-75248 Paris, France [2] Structure and Membrane Compartments, Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France [3] Cell and Tissue Imaging Facility, Infrastructures en Biologie Sante et Agronomie (IBiSA), Paris F-75248, France
| | - Graca Raposo
- 1] Institut Curie, UMR 144, CNRS, F-75248 Paris, France [2] Structure and Membrane Compartments, Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France [3] Cell and Tissue Imaging Facility, Infrastructures en Biologie Sante et Agronomie (IBiSA), Paris F-75248, France
| | | | - Jyotsna Dhawan
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India [2] CSIR-Center for Cellular and Molecular Biology, Hyderabad, India
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160
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Exosomes as Hedgehog carriers in cytoneme-mediated transport and secretion. Nat Commun 2014; 5:5649. [DOI: 10.1038/ncomms6649] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 10/22/2014] [Indexed: 12/12/2022] Open
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161
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Kornberg TB. Cytonemes and the dispersion of morphogens. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2014; 3:445-63. [PMID: 25186102 PMCID: PMC4199865 DOI: 10.1002/wdev.151] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 07/10/2014] [Accepted: 07/25/2014] [Indexed: 01/07/2023]
Abstract
Filopodia are cellular protrusions that have been implicated in many types of mechanosensory activities. Morphogens are signaling proteins that regulate the patterned development of embryos and tissues. Both have long histories that date to the beginnings of cell and developmental biology in the early 20th century, but recent findings tie specialized filopodia called cytonemes to morphogen movement and morphogen signaling. This review explores the conceptual and experimental background for a model of paracrine signaling in which the exchange of morphogens between cells is directed to sites where cytonemes directly link cells that produce morphogens to cells that receive and respond to them.
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Affiliation(s)
- Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
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162
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Ady JW, Desir S, Thayanithy V, Vogel RI, Moreira AL, Downey RJ, Fong Y, Manova-Todorova K, Moore MAS, Lou E. Intercellular communication in malignant pleural mesothelioma: properties of tunneling nanotubes. Front Physiol 2014; 5:400. [PMID: 25400582 PMCID: PMC4215694 DOI: 10.3389/fphys.2014.00400] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/26/2014] [Indexed: 01/16/2023] Open
Abstract
Malignant pleural mesothelioma is a particularly aggressive and locally invasive malignancy with a poor prognosis despite advances in understanding of cancer cell biology and development of new therapies. At the cellular level, cultured mesothelioma cells present a mesenchymal appearance and a strong capacity for local cellular invasion. One important but underexplored area of mesothelioma cell biology is intercellular communication. Our group has previously characterized in multiple histological subtypes of mesothelioma a unique cellular protrusion known as tunneling nanotubes (TnTs). TnTs are long, actin filament-based, narrow cytoplasmic extensions that are non-adherent when cultured in vitro and are capable of shuttling cellular cargo between connected cells. Our prior work confirmed the presence of nanotube structures in tumors resected from patients with human mesothelioma. In our current study, we quantified the number of TnTs/cell among various mesothelioma subtypes and normal mesothelial cells using confocal microscopic techniques. We also examined changes in TnT length over time in comparison to cell proliferation. We further examined potential approaches to the in vivo study of TnTs in animal models of cancer. We have developed novel approaches to study TnTs in aggressive solid tumor malignancies and define fundamental characteristics of TnTs in malignant mesothelioma. There is mounting evidence that TnTs play an important role in intercellular communication in mesothelioma and thus merit further investigation of their role in vivo.
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Affiliation(s)
- Justin W Ady
- Department of Surgery, Memorial Sloan-Kettering Cancer Center New York, NY, USA
| | - Snider Desir
- Division of Hematology, Oncology and Transplantation, University of Minnesota Minneapolis, MN, USA ; Integrative Biology and Physiology Program, University of Minnesota Minneapolis, Minnesota, USA
| | - Venugopal Thayanithy
- Division of Hematology, Oncology and Transplantation, University of Minnesota Minneapolis, MN, USA
| | - Rachel I Vogel
- Department of Biostatistics and Bioinformatics, Masonic Cancer Center, University of Minnesota Minneapolis, MN, USA
| | - André L Moreira
- Department of Pathology, Memorial Sloan-Kettering Cancer Center New York, NY, USA
| | - Robert J Downey
- Department of Surgery, Memorial Sloan-Kettering Cancer Center New York, NY, USA
| | - Yuman Fong
- Department of Surgery, Memorial Sloan-Kettering Cancer Center New York, NY, USA
| | | | - Malcolm A S Moore
- Department of Cell Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center New York, NY, USA
| | - Emil Lou
- Division of Hematology, Oncology and Transplantation, University of Minnesota Minneapolis, MN, USA
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163
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Damhofer H, Veenstra VL, Tol JAMG, van Laarhoven HWM, Medema JP, Bijlsma MF. Blocking Hedgehog release from pancreatic cancer cells increases paracrine signaling potency. J Cell Sci 2014; 128:129-39. [PMID: 25359882 DOI: 10.1242/jcs.157966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Members of the Hedgehog (Hh) family of morphogens play crucial roles in development but are also involved in the progression of certain types of cancer. Despite being synthesized as hydrophobic dually lipid-modified molecules, and thus being strongly membrane-associated, Hh ligands are able to spread through tissues and act on target cells several cell diameters away. Various mechanisms that mediate Hh release have been discussed in recent years; however, little is known about dispersion of this ligand from cancer cells. Using co-culture models in conjunction with a newly developed reporter system, we were able to show that different members of the ADAM family of metalloproteinases strongly contribute to the release of endogenous bioactive Hh from pancreatic cancer cells, but that this solubilization decreases the potency of cancer cells to signal to adjacent stromal cells in direct co-culture models. These findings imply that under certain conditions, cancer-cell-tethered Hh molecules are the more potent signaling activators and that retaining Hh on the surface of cancer cells can unexpectedly increase the effective signaling range of this ligand, depending on tissue context.
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Affiliation(s)
- Helene Damhofer
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Veronique L Veenstra
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Johanna A M G Tol
- Department of Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Hanneke W M van Laarhoven
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands Department of Medical Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Maarten F Bijlsma
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
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164
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Restrepo S, Zartman JJ, Basler K. Coordination of patterning and growth by the morphogen DPP. Curr Biol 2014; 24:R245-55. [PMID: 24650915 DOI: 10.1016/j.cub.2014.01.055] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The elegance of animal body plans derives from an intimate connection between function and form, which during organ formation is linked to patterning and growth. Yet, how patterning and growth are coordinated still remains largely a mystery. To study this question the Drosophila wing imaginal disc, an epithelial primordial organ that later forms the adult wing, has proven to be an invaluable and versatile model. Wing disc development is organized around a coordinate system provided by morphogens such as the TGF-β homolog Decapentaplegic (DPP). The function of DPP has been studied at multiple levels: ranging from the kinetics of gradient formation to the establishment and maintenance of target gene domains as well as DPP's role in growth control. Here, we focus on recent publications that both enrich our view of DPP signaling but also highlight outstanding questions of how DPP coordinates patterning and growth during development.
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Affiliation(s)
- Simon Restrepo
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057, Switzerland
| | - Jeremiah J Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick Hall, Notre Dame, IN 46556, USA
| | - Konrad Basler
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057, Switzerland.
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165
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Kornberg TB. The contrasting roles of primary cilia and cytonemes in Hh signaling. Dev Biol 2014; 394:1-5. [PMID: 25072627 DOI: 10.1016/j.ydbio.2014.07.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 07/11/2014] [Accepted: 07/19/2014] [Indexed: 12/16/2022]
Abstract
Hedgehog (Hh) is a paracrine signaling protein with major roles in development and disease. In vertebrates and invertebrates, Hh signal transduction is carried out almost entirely by evolutionarily conserved components, and in both, intercellular movement of Hh is mediated by cytonemes - specialized filopodia that serve as bridges that bring distant cells into contact. A significant difference is the role of the primary cilium, a slender, tubulin-based protuberance of many vertebrate cells. Although the primary cilium is essential for Hh signaling in cells that have one, most Drosophila cells lack a primary cilium. This perspective addresses the roles of primary cilia and cytonemes, and proposes that for Hh signaling, the role of primary cilia is to provide a specialized hydrophobic environment that hosts lipid-modified Hh and other components of Hh signal transduction after Hh has traveled from elsewhere in the cell. Implicit in this model is the idea that initial binding and uptake of Hh is independent of and segregated from the processes of signal transduction and activation.
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Affiliation(s)
- Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, United States.
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166
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Cdon acts as a Hedgehog decoy receptor during proximal-distal patterning of the optic vesicle. Nat Commun 2014; 5:4272. [PMID: 25001599 PMCID: PMC4102123 DOI: 10.1038/ncomms5272] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 05/26/2014] [Indexed: 02/06/2023] Open
Abstract
Patterning of the vertebrate optic vesicle into proximal/optic stalk and distal/neural retina involves midline-derived Hedgehog (Hh) signalling, which promotes stalk specification. In the absence of Hh signalling, the stalks are not specified, causing cyclopia. Recent studies showed that the cell adhesion molecule Cdon forms a heteromeric complex with the Hh receptor Patched 1 (Ptc1). This receptor complex binds Hh and enhances signalling activation, indicating that Cdon positively regulates the pathway. Here we show that in the developing zebrafish and chick optic vesicle, in which cdon and ptc1 are expressed with a complementary pattern, Cdon acts as a negative Hh signalling regulator. Cdon predominantly localizes to the basolateral side of neuroepithelial cells, promotes the enlargement of the neuroepithelial basal end-foot and traps Hh protein, thereby limiting its dispersion. This Ptc-independent function protects the retinal primordium from Hh activity, defines the stalk/retina boundary and thus the correct proximo-distal patterning of the eye. The Drosophila homologue of the vertebrate cell surface glycoprotein Cdon binds Hedgehog ligand and thereby prevents its diffusion. Here, the authors provide evidence for a similar mechanism during vertebrate optic vesicle patterning, where Cdon acts as a negative regulator of Hedgehog signalling to define the boundary between the optic stalk and the retina.
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167
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Guerrero I, Kornberg TB. Hedgehog and its circuitous journey from producing to target cells. Semin Cell Dev Biol 2014; 33:52-62. [PMID: 24994598 DOI: 10.1016/j.semcdb.2014.06.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/23/2014] [Indexed: 12/12/2022]
Abstract
The hedgehog (Hh) signaling protein has essential roles in the growth, development and regulation of many vertebrate and invertebrate organs. The processes that make Hh and prepare it for release from producing cells and that move it to target cells are both diverse and complex. This article reviews the essential features of these processes and highlights recent work that provides a novel framework to understand how these processes contribute to an integrated pathway.
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Affiliation(s)
- Isabel Guerrero
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
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168
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Majumdar R, Sixt M, Parent CA. New paradigms in the establishment and maintenance of gradients during directed cell migration. Curr Opin Cell Biol 2014; 30:33-40. [PMID: 24959970 DOI: 10.1016/j.ceb.2014.05.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 11/16/2022]
Abstract
Directional guidance of migrating cells is relatively well explored in the reductionist setting of cell culture experiments. Here spatial gradients of chemical cues as well as gradients of mechanical substrate characteristics prove sufficient to attract single cells as well as their collectives. How such gradients present and act in the context of an organism is far less clear. Here we review recent advances in understanding how guidance cues emerge and operate in complex physiological settings.
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Affiliation(s)
- Ritankar Majumdar
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Michael Sixt
- IST Austria (Institute of Science and Technology Austria), 3400 Klostemeuburg, Austria
| | - Carole A Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
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169
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Specialized filopodia: at the 'tip' of morphogen transport and vertebrate tissue patterning. Curr Opin Genet Dev 2014; 27:67-73. [PMID: 24907447 DOI: 10.1016/j.gde.2014.03.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 03/19/2014] [Accepted: 03/26/2014] [Indexed: 11/24/2022]
Abstract
For over a century, biologists have strived to unravel the mechanisms that establish how cells are informed of their position in the embryo and differentiate to give rise to complex organs and structures. However, the historical idea that one predominant mode of ligand transport, largely accounted for by free diffusion, can explain how all signaling molecules, known as morphogens, control tissue patterning has greatly hindered our ability to fully appreciate the complexities driving the delivery and reception of signaling molecules at a distance. In reality, a cell's shape, morphology, and location change continuously as development progresses. Thus, cellular context poses distinct challenges for morphogen transport in each unique cellular environment. Emerging studies reveal that some cells overcome such obstacles in an unexpected manner: via long, cellular projections, or specialized filopodia, that link distant cells and traffic signaling components. Here, we will review recent findings describing specialized filopodia and discuss the potential mechanisms and implications for filopodia-based long-range cell signaling and communication, particularly within the developing vertebrate embryo.
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170
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Kornberg TB, Roy S. Communicating by touch--neurons are not alone. Trends Cell Biol 2014; 24:370-6. [PMID: 24560610 PMCID: PMC4037336 DOI: 10.1016/j.tcb.2014.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 01/02/2014] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
Long-distance cell-cell communication is essential for organ development and function. Whereas neurons communicate at long distances by transferring signals at sites of direct contact (i.e., at synapses), it has been presumed that the only way other cell types signal is by dispersing signals through extracellular fluid--indirectly. Recent evidence from Drosophila suggests that non-neuronal cells also exchange signaling proteins at sites of direct contact, even when long distances separate the cells. We review here contact-mediated signaling in neurons and discuss how this signaling mechanism is shared by other cell types.
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Affiliation(s)
- Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
| | - Sougata Roy
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
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171
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Affiliation(s)
- Pernille Rørth
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673
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172
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Hartl TA, Scott MP. Wing tips: The wing disc as a platform for studying Hedgehog signaling. Methods 2014; 68:199-206. [PMID: 24556557 DOI: 10.1016/j.ymeth.2014.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/03/2014] [Accepted: 02/06/2014] [Indexed: 12/26/2022] Open
Abstract
Hedgehog (Hh) signal transduction is necessary for the development of most mammalian tissues and can go awry and cause birth defects or cancer. Hh signaling was initially described in Drosophila, and much of what we know today about mammalian Hh signaling was directly guided by discoveries in the fly. Indeed, Hh signaling is a wonderful example of the use of non-vertebrate model organisms to make basic discoveries that lead to new disease treatment. The first pharmaceutical to treat hyperactive Hh signaling in Basal Cell Carcinoma was released in 2012, approximately 30 years after the isolation of Hh mutants in Drosophila. The study of Hh signaling has been greatly facilitated by the imaginal wing disc, a tissue with terrific experimental advantages. Studies using the wing disc have led to an understanding of Hh ligand processing, packaging into particles for transmission, secretion, reception, signal transduction, target gene activation, and tissue patterning. Here we describe the imaginal wing disc, how Hh patterns this tissue, and provide methods to use wing discs to study Hh signaling in Drosophila. The tools and approaches we highlight form the cornerstone of research efforts in many laboratories that use Drosophila to study Hh signaling, and are essential for ongoing discoveries.
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Affiliation(s)
- Tom A Hartl
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew P Scott
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA.
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173
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Jakobs P, Exner S, Schürmann S, Pickhinke U, Bandari S, Ortmann C, Kupich S, Schulz P, Hansen U, Seidler DG, Grobe K. Scube2 enhances proteolytic Shh processing from the surface of Shh-producing cells. J Cell Sci 2014; 127:1726-37. [PMID: 24522195 DOI: 10.1242/jcs.137695] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
All morphogens of the Hedgehog (Hh) family are synthesized as dual-lipidated proteins, which results in their firm attachment to the surface of the cell in which they were produced. Thus, Hh release into the extracellular space requires accessory protein activities. We suggested previously that the proteolytic removal of N- and C-terminal lipidated peptides (shedding) could be one such activity. More recently, the secreted glycoprotein Scube2 (signal peptide, cubulin domain, epidermal-growth-factor-like protein 2) was also implicated in the release of Shh from the cell membrane. This activity strictly depended on the CUB domains of Scube2, which derive their name from the complement serine proteases and from bone morphogenetic protein-1/tolloid metalloproteinases (C1r/C1s, Uegf and Bmp1). CUB domains function as regulators of proteolytic activity in these proteins. This suggested that sheddases and Scube2 might cooperate in Shh release. Here, we confirm that sheddases and Scube2 act cooperatively to increase the pool of soluble bioactive Shh, and that Scube2-dependent morphogen release is unequivocally linked to the proteolytic processing of lipidated Shh termini, resulting in truncated soluble Shh. Thus, Scube2 proteins act as protease enhancers in this setting, revealing newly identified Scube2 functions in Hh signaling regulation.
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Affiliation(s)
- Petra Jakobs
- The Institute for Physiological Chemistry and Pathobiochemistry, Westfälische Wilhelms Universität Münster, Waldeyerstrasse 15, D-48149 Münster, Germany
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174
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Abstract
In vivo time-lapse imaging and functional tests bring fresh evidence that the morphogen Hedgehog is conveyed to target cells via long filopodia extensions, dubbed cytonemes. This study provides the tools and conceptual framework to understand how cytonemes form and carry morphogens.
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Affiliation(s)
- James Briscoe
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
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