1
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Chatzikyriakou P, Brempou D, Quinn M, Fishbein L, Noberini R, Anastopoulos IN, Tufton N, Lim ES, Obholzer R, Hubbard JG, Moonim M, Bonaldi T, Nathanson KL, Izatt L, Oakey RJ. A comprehensive characterisation of phaeochromocytoma and paraganglioma tumours through histone protein profiling, DNA methylation and transcriptomic analysis genome wide. Clin Epigenetics 2023; 15:196. [PMID: 38124114 PMCID: PMC10734084 DOI: 10.1186/s13148-023-01598-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 11/08/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Pathogenic variants have been identified in more than 15 susceptibility genes; associated tumours are grouped into three Clusters, reinforced by their transcriptional profiles. Cluster 1A PPGLs have pathogenic variants affecting enzymes of the tricarboxylic acid cycle, including succinate dehydrogenase. Within inherited PPGLs, these are the most common. PPGL tumours are known to undergo epigenetic reprograming, and here, we report on global histone post-translational modifications and DNA methylation levels, alongside clinical phenotypes. RESULTS Out of the 25 histone post-translational modifications examined, Cluster 1A PPGLs were distinguished from other tumours by a decrease in hyper-acetylated peptides and an increase in H3K4me2. DNA methylation was compared between tumours from individuals who developed metastatic disease versus those that did not. The majority of differentially methylated sites identified tended to be completely methylated or unmethylated in non-metastatic tumours, with low inter-sample variance. Metastatic tumours by contrast consistently had an intermediate DNA methylation state, including the ephrin receptor EPHA4 and its ligand EFNA3. Gene expression analyses performed to identify genes involved in metastatic tumour behaviour pin-pointed a number of genes previously described as mis-regulated in Cluster 1A tumours, as well as highlighting the tumour suppressor RGS22 and the pituitary tumour-transforming gene PTTG1. CONCLUSIONS Combined transcriptomic and DNA methylation analyses revealed aberrant pathways, including ones that could be implicated in metastatic phenotypes and, for the first time, we report a decrease in hyper-acetylated histone marks in Cluster 1 PPGLs.
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Affiliation(s)
- Prodromos Chatzikyriakou
- Department of Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Comprehensive Cancer Centre, King's College London, London, SE5 8AF, UK
| | - Dimitria Brempou
- Department of Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Mark Quinn
- Department of Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Lauren Fishbein
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Abramson Cancer Center, Perelman School of Medicine, Philadelphia, PA, USA
- Division of Endocrinology, Diabetes and Metabolism in the Department of Medicine Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Roberta Noberini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Ioannis N Anastopoulos
- Department of Biomolecular Engineering, UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Nicola Tufton
- Department of Endocrinology, St. Bartholomew's Hospital, Barts Health NHS Trust, and William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Eugenie S Lim
- Department of Endocrinology, St. Bartholomew's Hospital, Barts Health NHS Trust, and William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Rupert Obholzer
- Department of ENT and Skull Base Surgery, Guy's and St Thomas' NHS Foundation Trust, London, SE1 9RT, UK
| | - Johnathan G Hubbard
- Department of Endocrine Surgery, Guy's and St Thomas' NHS Foundation Trust, London, SE1 9RT, UK
| | - Mufaddal Moonim
- Department of Cellular Pathology, Guy's and St Thomas' NHS Foundation Trust, London, SE1 9RT, UK
- Imperial College Healthcare NHS Trust, London, UK
| | - Tiziana Bonaldi
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
- Department of Oncology and Hematology-Oncology, University of Milano, Via Festa del Perdono 7, 20122, Milan, Italy
| | - Katherine L Nathanson
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Abramson Cancer Center, Perelman School of Medicine, Philadelphia, PA, USA
| | - Louise Izatt
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, SE1 9RT, UK
| | - Rebecca J Oakey
- Department of Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK.
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2
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Pospíšil J, Hrabovský M, Bohačiaková D, Hovádková Z, Jurásek M, Mlčoušková J, Paruch K, Nevolová Š, Damborsky J, Hampl A, Jaros J. Geometric Control of Cell Behavior by Biomolecule Nanodistribution. ACS Biomater Sci Eng 2022; 8:4789-4806. [PMID: 36202388 PMCID: PMC9667466 DOI: 10.1021/acsbiomaterials.2c00650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Many dynamic interactions within the cell microenvironment
modulate
cell behavior and cell fate. However, the pathways and mechanisms
behind cell–cell or cell–extracellular matrix interactions
remain understudied, as they occur at a nanoscale level. Recent progress
in nanotechnology allows for mimicking of the microenvironment at
nanoscale in vitro; electron-beam lithography (EBL)
is currently the most promising technique. Although this nanopatterning
technique can generate nanostructures of good quality and resolution,
it has resulted, thus far, in the production of only simple shapes
(e.g., rectangles) over a relatively small area (100 × 100 μm),
leaving its potential in biological applications unfulfilled. Here,
we used EBL for cell-interaction studies by coating cell-culture-relevant
material with electron-conductive indium tin oxide, which formed nanopatterns
of complex nanohexagonal structures over a large area (500 ×
500 μm). We confirmed the potential of EBL for use in cell-interaction
studies by analyzing specific cell responses toward differentially
distributed nanohexagons spaced at 1000, 500, and 250 nm. We found
that our optimized technique of EBL with HaloTags enabled the investigation
of broad changes to a cell-culture-relevant surface and can provide
an understanding of cellular signaling mechanisms at a single-molecule
level.
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Affiliation(s)
- Jakub Pospíšil
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.,Core Facility Cellular Imaging, CEITEC, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Miloš Hrabovský
- TESCAN Orsay Holding a.s., Libušina tř. 863, Brno 623 00, Czech Republic
| | - Dáša Bohačiaková
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic
| | | | | | - Jarmila Mlčoušková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Kamil Paruch
- International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic.,Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Šárka Nevolová
- International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic.,Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Jiri Damborsky
- International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic.,Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Aleš Hampl
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic
| | - Josef Jaros
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Pekařská 53, Brno 656 91, Czech Republic
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3
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Chu LY, Huang BL, Huang XC, Peng YH, Xie JJ, Xu YW. EFNA1 in gastrointestinal cancer: Expression, regulation and clinical significance. World J Gastrointest Oncol 2022; 14:973-988. [PMID: 35646281 PMCID: PMC9124989 DOI: 10.4251/wjgo.v14.i5.973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/17/2021] [Accepted: 04/04/2022] [Indexed: 02/06/2023] Open
Abstract
Ephrin-A1 is a protein that in humans is encoded by the EFNA1 gene. The ephrins and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases which play an indispensable role in normal growth and development or in the pathophysiology of various tumors. The role of EFNA1 in tumorigenesis and development is complex and depends on the cell type and microenvironment which in turn affect the expression of EFNA1. This article reviews the expression, prognostic value, regulation and clinical significance of EFNA1 in gastrointestinal tumors.
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Affiliation(s)
- Ling-Yu Chu
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Bin-Liang Huang
- Department of Clinical Laboratory Medicine, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Xu-Chun Huang
- Department of Clinical Laboratory Medicine, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Yu-Hui Peng
- Department of Clinical Laboratory Medicine, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
- Guangdong Esophageal Cancer Research Institute, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Jian-Jun Xie
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Yi-Wei Xu
- Department of Clinical Laboratory Medicine, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
- Guangdong Esophageal Cancer Research Institute, The Cancer Hospital of Shantou University Medical College, Shantou 515041, Guangdong Province, China
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4
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de Boer ECW, van Gils JM, van Gils MJ. Ephrin-Eph signaling usage by a variety of viruses. Pharmacol Res 2020; 159:105038. [PMID: 32565311 DOI: 10.1016/j.phrs.2020.105038] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022]
Abstract
Ephrin-Eph signaling is a receptor tyrosine kinase signaling pathway involved in a variety of cellular mechanisms, of which many are related to the adhesion or migration of cells. Both the Eph receptor and ephrin ligand are abundantly present on a wide variety of cell types, and strongly evolutionary conserved. This review provides an overview of how 18 genetically diverse viruses utilize the Eph receptor (Eph), ephrin ligand (ephrin) or ephrin-Eph signaling to their advantage in their viral life cycle. Both Ephs and ephrins have been shown to serve as entry receptors for a variety of viruses, via both membrane fusion and endocytosis. Ephs and ephrins are also involved in viral transmission by vectors, associated with viral replication or persistence and lastly to neurological damage caused by viral infection. Although therapeutic opportunities targeting Ephs or ephrins do not seem feasible yet, the current research does propose two models for the viral usage of ephrin-Eph signaling. Firstly, the viral entry model, in which membrane molecules are used for viral entry, leading to cells being used for replication or as a transporter. Secondly, the advantageous expression ephrin-Eph signaling model, where viruses adapt the expression of Ephs or ephrins to change cell-cell interaction to their advantage. These models can guide future research questions on the usage of Ephs or ephrins by viruses and therapeutic opportunities.
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Affiliation(s)
- Esther C W de Boer
- Department of Medical Microbiology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Meibergdreef 9, Amsterdam, the Netherlands
| | - Janine M van Gils
- Einthoven Laboratory for Vascular and Regenerative Medicine, Department of Internal Medicine, Leiden University Medical Center, Leiden, the Netherlands.
| | - Marit J van Gils
- Department of Medical Microbiology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Meibergdreef 9, Amsterdam, the Netherlands.
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5
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Integrins Have Cell-Type-Specific Roles in the Development of Motor Neuron Connectivity. J Dev Biol 2019; 7:jdb7030017. [PMID: 31461926 PMCID: PMC6787651 DOI: 10.3390/jdb7030017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/11/2019] [Accepted: 08/22/2019] [Indexed: 01/16/2023] Open
Abstract
Formation of the nervous system requires a complex series of events including proper extension and guidance of neuronal axons and dendrites. Here we investigate the requirement for integrins, a class of transmembrane cell adhesion receptors, in regulating these processes across classes of C. elegans motor neurons. We show α integrin/ina-1 is expressed by both GABAergic and cholinergic motor neurons. Despite this, our analysis of hypomorphic ina-1(gm144) mutants indicates preferential involvement of α integrin/ina-1 in GABAergic commissural development, without obvious involvement in cholinergic commissural development. The defects in GABAergic commissures of ina-1(gm144) mutants included both premature termination and guidance errors and were reversed by expression of wild type ina-1 under control of the native ina-1 promoter. Our results also show that α integrin/ina-1 is important for proper outgrowth and guidance of commissures from both embryonic and post-embryonic born GABAergic motor neurons, indicating an ongoing requirement for integrin through two phases of GABAergic neuron development. Our findings provide insights into neuron-specific roles for integrin that would not be predicted based solely upon expression analysis.
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6
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Niethamer TK, Bush JO. Getting direction(s): The Eph/ephrin signaling system in cell positioning. Dev Biol 2019; 447:42-57. [PMID: 29360434 PMCID: PMC6066467 DOI: 10.1016/j.ydbio.2018.01.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/21/2017] [Accepted: 01/18/2018] [Indexed: 12/16/2022]
Abstract
In vertebrates, the Eph/ephrin family of signaling molecules is a large group of membrane-bound proteins that signal through a myriad of mechanisms and effectors to play diverse roles in almost every tissue and organ system. Though Eph/ephrin signaling has functions in diverse biological processes, one core developmental function is in the regulation of cell position and tissue morphology by regulating cell migration and guidance, cell segregation, and boundary formation. Often, the role of Eph/ephrin signaling is to translate patterning information into physical movement of cells and changes in morphology that define tissue and organ systems. In this review, we focus on recent advances in the regulation of these processes, and our evolving understanding of the in vivo signaling mechanisms utilized in distinct developmental contexts.
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Affiliation(s)
- Terren K Niethamer
- Department of Cell and Tissue Biology, Program in Craniofacial Biology, and Institute of Human Genetics, University of California at San Francisco, San Francisco, CA 94143, USA
| | - Jeffrey O Bush
- Department of Cell and Tissue Biology, Program in Craniofacial Biology, and Institute of Human Genetics, University of California at San Francisco, San Francisco, CA 94143, USA.
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7
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Wijeratne D, Rodger J, Stevenson A, Wallace H, Prêle CM, Wood FM, Fear MW. Ephrin-A2 affects wound healing and scarring in a murine model of excisional injury. Burns 2018; 45:682-690. [PMID: 30482614 DOI: 10.1016/j.burns.2018.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/14/2018] [Accepted: 10/04/2018] [Indexed: 12/18/2022]
Abstract
Ephrin ligand/Eph receptor signaling is important in both tissue development and homeostasis. There is increasing evidence that Ephrin/Eph signaling is important in the skin, involved in hair follicle cycling, epidermal differentiation, cutaneous innervation and skin cancer. However, there is currently limited information on the role of Ephrin/Eph signaling in cutaneous wound healing. Here we report the effects of the Ephrin-A2 and A5 ligands on wound healing. Using Ephrin-A2-/-, Ephrin-A5-/- and Ephrin-A2A5-/- transgenic mice, in vitro wound healing assays were conducted using isolated keratinocytes and fibroblasts. Ephrin-A2-/-, Ephrin-A2A5-/- and wild type mice with excisional wounds were used to analyze the impact of these ligands on wound closure, scar outcome, collagen orientation and re-innervation in vivo. The absence of the Ephrin-A2 and A5 ligands did not have any effect on dermal fibroblast proliferation or on fibroblast or keratinocyte migration. The loss of Ephrin-A2 and A5 ligands did not impact on the rate of wound closure or re-innervation after injury. However, changes in the gross morphology of the healed scar and in collagen histology of the scar dermis were observed in transgenic mice. Therefore Ephrin-A2 and A5 ligands may play an important role in final scar appearance associated with collagen deposition and structure.
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Affiliation(s)
- Dulharie Wijeratne
- Burn Injury Research Unit, School of Biomedical Sciences, The University of Western Australia, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Australia
| | - Andrew Stevenson
- Burn Injury Research Unit, School of Biomedical Sciences, The University of Western Australia, Australia
| | - Hilary Wallace
- Burn Injury Research Unit, School of Biomedical Sciences, The University of Western Australia, Australia
| | - Cecilia M Prêle
- The Institute for Respiratory Health, The University of Western Australia, Nedlands, Western Australia, Australia; Centre for Cell Therapy and Regenerative Medicine, School of Biomedical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Fiona M Wood
- Burn Injury Research Unit, School of Biomedical Sciences, The University of Western Australia, Australia; Centre for Cell Therapy and Regenerative Medicine, School of Biomedical Sciences, The University of Western Australia, Crawley, Western Australia, Australia; The Fiona Wood Foundation, Perth, Western Australia, Australia; Burns Service of Western Australia, WA Department of Health, Perth, Western Australia, Australia
| | - Mark W Fear
- Burn Injury Research Unit, School of Biomedical Sciences, The University of Western Australia, Australia; The Institute for Respiratory Health, The University of Western Australia, Nedlands, Western Australia, Australia; The Fiona Wood Foundation, Perth, Western Australia, Australia.
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8
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Tosato G. Ephrin ligands and Eph receptors contribution to hematopoiesis. Cell Mol Life Sci 2017; 74:3377-3394. [PMID: 28589441 PMCID: PMC11107787 DOI: 10.1007/s00018-017-2566-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/12/2017] [Accepted: 06/01/2017] [Indexed: 12/12/2022]
Abstract
Hematopoietic stem and progenitor cells reside predominantly in the bone marrow. They supply billions of mature blood cells every day during life through maturation into multilineage progenitors and self-renewal. Newly produced mature cells serve to replenish the pool of circulating blood cells at the end of their life-span. These mature blood cells and a few hematopoietic progenitors normally exit the bone marrow through the sinusoidal vessels, a specialized venous vascular system that spreads throughout the bone marrow. Many signals regulate the coordinated mobilization of hematopoietic cells from the bone marrow to the circulation. In this review, we present recent advances on hematopoiesis and hematopoietic cell mobilization with a focus on the role of Ephrin ligands and their Eph receptors. These constitute a large family of transmembrane ligands and receptors that play critical roles in development and postnatally. New insights point to distinct roles of ephrin and Eph in different aspects of hematopoiesis.
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Affiliation(s)
- Giovanna Tosato
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 37, Room 4124, Bethesda, MD, 20892, USA.
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9
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Sun X, Li Y, He W, Ji C, Xia P, Wang Y, Du S, Li H, Raikhel N, Xiao J, Guo H. Pyrazinamide and derivatives block ethylene biosynthesis by inhibiting ACC oxidase. Nat Commun 2017; 8:15758. [PMID: 28604689 PMCID: PMC5472784 DOI: 10.1038/ncomms15758] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 04/25/2017] [Indexed: 12/30/2022] Open
Abstract
Ethylene is an important phytohormone that promotes the ripening of fruits and senescence of flowers thereby reducing their shelf lives. Specific ethylene biosynthesis inhibitors would help to decrease postharvest loss. Here, we identify pyrazinamide (PZA), a clinical drug used to treat tuberculosis, as an inhibitor of ethylene biosynthesis in Arabidopsis thaliana, using a chemical genetics approach. PZA is converted to pyrazinecarboxylic acid (POA) in plant cells, suppressing the activity of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), the enzyme catalysing the final step of ethylene formation. The crystal structures of Arabidopsis ACO2 in complex with POA or 2-Picolinic Acid (2-PA), a POA-related compound, reveal that POA/2-PA bind at the active site of ACO, preventing the enzyme from interacting with its natural substrates. Our work suggests that PZA and its derivatives may be promising regulators of plant metabolism, in particular ethylene biosynthesis.
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Affiliation(s)
- Xiangzhong Sun
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.,Peking-Tsinghua Center for Life Sciences, Beijing 100871, China.,Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yaxin Li
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wenrong He
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.,Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92507, USA
| | - Chenggong Ji
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Peixue Xia
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.,Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
| | - Yichuan Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Shuo Du
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hongjiang Li
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.,Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92507, USA
| | - Natasha Raikhel
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92507, USA
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.,Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
| | - Hongwei Guo
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China.,Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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10
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Hegde S, Srivastava O. Different gene knockout/transgenic mouse models manifesting persistent fetal vasculature: Are integrins to blame for this pathological condition? Life Sci 2016; 171:30-38. [PMID: 28039002 DOI: 10.1016/j.lfs.2016.12.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/15/2016] [Accepted: 12/26/2016] [Indexed: 12/30/2022]
Abstract
Persistent fetal vasculature (PFV) occurs as a result of a failure of fetal vasculature to undergo normal programmed involution. During development, before the formation of retinal vessels, the lens and the inner retina are nourished by the hyaloid vasculature. Hyaloid vessels extend from the optic nerve and run through the vitreous to encapsulate the lens. As fetal retinal vessels develop, hyaloid vasculature naturally regresses. Failure of regression of the hyaloid artery has been shown to lead to severe congenital pathologies. Studies on childhood blindness and visual impairment in the United States have shown that PFV accounts for 4.8% of total blindness. Although PFV is a serious developmental disease affecting the normal visual development pathway, the exact regulatory mechanism responsible for the regression of the hyaloid artery is still unknown. In this review, we have summarized the cellular defects associated with different knockout models that manifest features of persistent fetal vasculature. Based on similar cellular defects observed in different knockouts (KO)s such as altered migration, increased proliferation and decreased apoptosis and, the known role of integrins in the regulation of these cellular behaviors, we propose here that integrins may play a significant role in the pathophysiology of persistent fetal vasculature disease.
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Affiliation(s)
- Shylaja Hegde
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
| | - Om Srivastava
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35294, United States
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11
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Averaimo S, Assali A, Ros O, Couvet S, Zagar Y, Genescu I, Rebsam A, Nicol X. A plasma membrane microdomain compartmentalizes ephrin-generated cAMP signals to prune developing retinal axon arbors. Nat Commun 2016; 7:12896. [PMID: 27694812 PMCID: PMC5059439 DOI: 10.1038/ncomms12896] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 08/11/2016] [Indexed: 01/11/2023] Open
Abstract
The development of neuronal circuits is controlled by guidance molecules that are hypothesized to interact with the cholesterol-enriched domains of the plasma membrane termed lipid rafts. Whether such domains enable local intracellular signalling at the submicrometre scale in developing neurons and are required for shaping the nervous system connectivity in vivo remains controversial. Here, we report a role for lipid rafts in generating domains of local cAMP signalling in axonal growth cones downstream of ephrin-A repulsive guidance cues. Ephrin-A-dependent retraction of retinal ganglion cell axons involves cAMP signalling restricted to the vicinity of lipid rafts and is independent of cAMP modulation outside of this microdomain. cAMP modulation near lipid rafts controls the pruning of ectopic axonal branches of retinal ganglion cells in vivo, a process requiring intact ephrin-A signalling. Together, our findings indicate that lipid rafts structure the subcellular organization of intracellular cAMP signalling shaping axonal arbors during the nervous system development.
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Affiliation(s)
- Stefania Averaimo
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
| | - Ahlem Assali
- Sorbonne Universités, UPMC University Paris 06, UMR_S 839, Paris F-75005, France.,INSERM UMR_S 839, Paris F-75005, France.,Institut du Fer à Moulin, Paris F-75005, France
| | - Oriol Ros
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
| | - Sandrine Couvet
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
| | - Yvrick Zagar
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
| | - Ioana Genescu
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
| | - Alexandra Rebsam
- Sorbonne Universités, UPMC University Paris 06, UMR_S 839, Paris F-75005, France.,INSERM UMR_S 839, Paris F-75005, France.,Institut du Fer à Moulin, Paris F-75005, France
| | - Xavier Nicol
- Sorbonne Universités, UPMC University Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012, France.,CNRS, UMR_7210, Paris F-75012, France.,INSERM, UMR_S 968, Paris F-75012, France
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12
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Dexamethasone Regulates EphA5, a Potential Inhibitory Factor with Osteogenic Capability of Human Bone Marrow Stromal Cells. Stem Cells Int 2016; 2016:1301608. [PMID: 27057165 PMCID: PMC4736961 DOI: 10.1155/2016/1301608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 11/30/2015] [Accepted: 12/03/2015] [Indexed: 11/18/2022] Open
Abstract
We previously demonstrated the importance of quality management procedures for the handling of human bone marrow stromal cells (hBMSCs) and provided evidence for the existence of osteogenic inhibitor molecules in BMSCs. One candidate inhibitor is the ephrin type-A receptor 5 (EphA5), which is expressed in hBMSCs and upregulated during long-term culture. In this study, forced expression of EphA5 diminished the expression of osteoblast phenotypic markers. Downregulation of endogenous EphA5 by dexamethasone treatment promoted osteoblast marker expression. EphA5 could be involved in the normal growth regulation of BMSCs and could be a potential marker for replicative senescence. Although Eph forward signaling stimulated by ephrin-B-Fc promoted the expression of ALP mRNA in BMSCs, exogenous addition of EphA5-Fc did not affect the ALP level. The mechanism underlying the silencing of EphA5 in early cultures remains unclear. EphA5 promoter was barely methylated in hBMSCs while histone deacetylation could partially suppress EphA5 expression in early-passage cultures. In repeatedly passaged cultures, the upregulation of EphA5 independent of methylation could competitively inhibit osteogenic signal transduction pathways such as EphB forward signaling. Elucidation of the potential inhibitory function of EphA5 in hBMSCs may provide an alternative approach for lineage differentiation in cell therapy strategies and regenerative medicine.
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13
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Tan J, Tao Q, Niu H, Zhang Z, Li D, Gong Z, Weng Y, Li Z. A novel allele of monoecious (m) locus is responsible for elongated fruit shape and perfect flowers in cucumber (Cucumis sativus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:2483-93. [PMID: 26350497 DOI: 10.1007/s00122-015-2603-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/28/2015] [Indexed: 05/20/2023]
Abstract
A 14 bp deletion in CsACS2 gene encoding a truncated loss-of-function protein is responsible for elongated fruit shape and perfect flowers in cucumber. In cucumber (Cucumis sativus L.), sex expression and fruit shape are important components of biological and marketable yield. The association of fruit shape and sex expression is a very interesting phenomenon. The sex determination is controlled primarily by the F (female) and M (monoecy) loci. Homozygous recessive mm plants bear bisexual (perfect) flowers, and the fruits are often round shaped. CsACS2 encoding the 1-aminocyclopropane-1-carboxylic acid synthase has been shown to be the candidate gene for the m locus. We recently identified an andromonoecious cucumber line H38 that has bisexual flowers but elongated fruits. To rapidly clone this monoecious gene in H38, we developed a tri-parent mapping strategy, which took advantage of the high-density Gy14 × 9930 cucumber genetic map and the powder of bulk segregant analysis. Microsatellite markers from the Gy14 × 9930 map were used to screen two pairs of unisexual and bisexual bulks constructed from H38 × Gy14 and H38 × 9930 F2 populations. Polymorphic markers were identified and used to quickly develop a framework map and place the monoecious locus of H38 in cucumber chromosome 1. Further fine mapping allowed identification of a novel allele, m-1, at the monoecious locus to control the bisexual flower in H38, which was due to a 14 bp deletion in the third exon of the CsACS2 gene encoding a truncated loss-of-function protein of the cucumber 1-aminocyclopropane-1-carboxylic acid synthase. This new allele provides a valuable tool in understanding the molecular mechanisms of CsACS2 in the relationships of sex determination, fruit shape, and CsACS activities in cucumber.
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Affiliation(s)
- Junyi Tan
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Qianyi Tao
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huanhuan Niu
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhen Zhang
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Dandan Li
- Agricultural College, Heilongjiang Bayi Agriculture University, Daqing, 163319, Heilongjiang, China
| | - Zhenhui Gong
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yiqun Weng
- Horticulture Department, University of Wisconsin, Madison, WI, 53706, USA
| | - Zheng Li
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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14
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Pitulescu ME, Adams RH. Regulation of signaling interactions and receptor endocytosis in growing blood vessels. Cell Adh Migr 2015; 8:366-77. [PMID: 25482636 DOI: 10.4161/19336918.2014.970010] [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] [Indexed: 01/02/2023] Open
Abstract
Blood vessels and the lymphatic vasculature are extensive tubular networks formed by endothelial cells that have several indispensable functions in the developing and adult organism. During growth and tissue regeneration but also in many pathological settings, these vascular networks expand, which is critically controlled by the receptor EphB4 and the ligand ephrin-B2. An increasing body of evidence links Eph/ephrin molecules to the function of other receptor tyrosine kinases and cell surface receptors. In the endothelium, ephrin-B2 is required for clathrin-dependent internalization and full signaling activity of VEGFR2, the main receptor for vascular endothelial growth factor. In vascular smooth muscle cells, ephrin-B2 antagonizes clathrin-dependent endocytosis of PDGFRβ and controls the balanced activation of different signal transduction processes after stimulation with platelet-derived growth factor. This review summarizes the important roles of Eph/ephrin molecules in vascular morphogenesis and explains the function of ephrin-B2 as a molecular hub for receptor endocytosis in the vasculature.
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Key Words
- Ang, angiopoietin
- CHC, clathrin heavy chains
- CLASP, clathrin-associated-sorting protein
- CV, cardinal vein
- DA, dorsal aorta
- EC, endothelial cell
- EEA1, early antigen 1
- Eph
- Ephrin-B2ΔV, ephrin-B2 deletion of C-terminal PDZ binding motif
- HSPG, heparan sulfate proteoglycan
- JNK, c-Jun N-terminal kinase
- LEC, lymphatic endothelial cells
- LRP1, Low density lipoprotein receptor-related protein 1
- MVB, multivesicular body
- NRP, neuropilin
- PC, pericytes
- PDGF, platelet-derived growth factor
- PDGFR, platelet-derived growth factor receptor
- PTC, peritubular capillary
- PlGF, placental growth factor
- RTK, receptor tyrosine kinase
- VEGF, Vascular endothelial growth factor
- VEGFR, Vascular endothelial growth factor receptor
- VSMC, vascular smooth muscle cells.
- aPKC, atypical protein kinase C
- endocytosis
- endothelial cells
- ephrin
- mural cells
- receptor
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Affiliation(s)
- Mara E Pitulescu
- a Department of Tissue Morphogenesis; Max Planck Institute for Molecular Biomedicine; and Faculty of Medicine , University of Münster ; Münster , Germany
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15
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EphB2 regulates contact-dependent and contact-independent signaling to control platelet function. Blood 2014; 125:720-30. [PMID: 25370417 DOI: 10.1182/blood-2014-06-585083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Eph kinases, EphA4 and EphB1, and their ligand, ephrinB1, have been previously reported to be present in platelets where they contribute to thrombus stability. Although thrombus formation allows for Eph-ephrin engagement and bidirectional signaling, the importance specifically of Eph kinase or ephrin signaling in regulating platelet function remained unidentified. In the present study, a genetic approach was used in mice to establish the contribution of signaling orchestrated by the cytoplasmic domain of EphB2 (a newly discovered Eph kinase in platelets) in platelet activation and thrombus formation. We conclude that EphB2 signaling is involved in the regulation of thrombus formation and clot retraction. Furthermore, the cytoplasmic tail of this Eph kinase regulates initial platelet activation in a contact-independent manner in the absence of Eph-ephrin ligation between platelets. Together, these data demonstrate that EphB2 signaling not only modulates platelet function within a thrombus but is also involved in the regulation of the function of isolated platelets in a contact-independent manner.
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16
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Cramer KS, Gabriele ML. Axon guidance in the auditory system: multiple functions of Eph receptors. Neuroscience 2014; 277:152-62. [PMID: 25010398 DOI: 10.1016/j.neuroscience.2014.06.068] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/05/2014] [Accepted: 06/28/2014] [Indexed: 11/29/2022]
Abstract
The neural pathways of the auditory system underlie our ability to detect sounds and to transform amplitude and frequency information into rich and meaningful perception. While it shares some organizational features with other sensory systems, the auditory system has some unique functions that impose special demands on precision in circuit assembly. In particular, the cochlear epithelium creates a frequency map rather than a space map, and specialized pathways extract information on interaural time and intensity differences to permit sound source localization. The assembly of auditory circuitry requires the coordinated function of multiple molecular cues. Eph receptors and their ephrin ligands constitute a large family of axon guidance molecules with developmentally regulated expression throughout the auditory system. Functional studies of Eph/ephrin signaling have revealed important roles at multiple levels of the auditory pathway, from the cochlea to the auditory cortex. These proteins provide graded cues used in establishing tonotopically ordered connections between auditory areas, as well as discrete cues that enable axons to form connections with appropriate postsynaptic partners within a target area. Throughout the auditory system, Eph proteins help to establish patterning in neural pathways during early development. This early targeting, which is further refined with neuronal activity, establishes the precision needed for auditory perception.
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Affiliation(s)
- K S Cramer
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, United States.
| | - M L Gabriele
- Department of Biology, James Madison University, Harrisonburg, VA 22807, United States
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17
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Stanic K, Vera A, González M, Recabal A, Astuya A, Torrejón M, Montecinos H, Caprile T. Complementary expression of EphA7 and SCO-spondin during posterior commissure development. Front Neuroanat 2014; 8:49. [PMID: 25009468 PMCID: PMC4068196 DOI: 10.3389/fnana.2014.00049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/02/2014] [Indexed: 12/05/2022] Open
Abstract
Bilaterally symmetric organisms need to exchange information between the two sides of their bodies in order to integrate sensory inputs and coordinate motor control. This exchange occurs through commissures formed by neurons that project axons across the midline to the contralateral side of the central nervous system. The posterior commissure is the first transversal axonal tract of the embryonic vertebrate brain. It is located in the dorsal portion of the prosomere 1, at the caudal diencephalon. The axons of the posterior commissure principally come from neurons of ventrolateral and dorsolateral pretectal nuclei (parvocellular and magnocellular nucleus of the posterior commissure, respectively) that extend their axons toward the dorsal region. The trajectory of these axons can be divided into the following three stages: (1) dorsal axon extension towards the lateral roof plate; (2) fasciculation in the lateral roof plate; and (3) midline decision of turning to the ipsilateral side or continuing to the opposite side. The mechanisms and molecules that guide the axons during these steps are unknown. In the present work, immunohistochemical and in situ hybridization analyses were performed, with results suggesting the participation of EphA7 in guiding axons from the ventral to the dorsal region of the prosomere 1 through the generation of an axonal corridor limited by repulsive EphA7 walls. At the lateral roof plate, the axons became fasciculated in presence of SCO-spondin until reaching the midline. Finally, EphA7 expression was observed in the diencephalic midline roof plate, specifically in the region where some axons turn to the ipsilateral side, suggesting its participation in this decision. In summary, the present work proposes a mechanism of posterior commissure formation orchestrated by the complementary expression of the axon guidance cues SCO-spondin and EphA7.
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Affiliation(s)
- Karen Stanic
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - América Vera
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - Melissa González
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - Antonia Recabal
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - Allison Astuya
- Laboratory of Cell Culture and Marine Genomics, Marine Biotechnology Unit, Faculty of Natural and Oceanographic Sciences and Program COPAS Sur-Austral, University of Concepción, Concepción , Chile
| | - Marcela Torrejón
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - Hernán Montecinos
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
| | - Teresa Caprile
- Axon Guidance Laboratory, Department of Cell Biology, Faculty of Biological Sciences, University of Concepción, Concepción , Chile
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18
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Shi HY, Zhang YX. Expression and regulation of pear 1-aminocyclopropane-1-carboxylic acid synthase gene (PpACS1a) during fruit ripening, under salicylic acid and indole-3-acetic acid treatment, and in diseased fruit. Mol Biol Rep 2014; 41:4147-54. [PMID: 24562629 DOI: 10.1007/s11033-014-3286-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 02/13/2014] [Indexed: 11/29/2022]
Abstract
In plants, the level of ethylene is determined by the activity of the key enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS). A gene encoding an ACC synthase protein was isolated from pear (Pyrus pyrifolia). This gene designated PpACS1a (GenBank accession no. KC632526) was 1488 bp in length with an open reading frame (ORF) encoding a protein of 495 amino acids that shared high similarity with other pear ACC synthase proteins. The PpACS1a was grouped into type-1 subfamily of plant ACS based on its conserved domain and phylogenetic status. Real-time quantitative PCR indicated that PpACS1a was differentially expressed in pear tissues and predominantly expressed in anthers. The expression signal of PpACS1a was also detected in fruit and leaves, but no signal was detected in shoots and petals. Furthermore, the PpACS1a expression was regulated during fruit ripening. In addition, the PpACS1a gene expression was regulated by salicylic acid (SA) and indole-3-acetic acid (IAA) in fruit. Moreover, the expression of the PpACS1a was up-regulated in diseased pear fruit. These results indicated that PpACS1a might be involved in fruit ripening and response to SA, IAA and disease.
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Affiliation(s)
- Hai-Yan Shi
- College of Horticulture, Agricultural University of Hebei, Baoding, 071001, China,
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19
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Xi HQ, Wu XS, Wei B, Chen L. Eph receptors and ephrins as targets for cancer therapy. J Cell Mol Med 2014; 16:2894-909. [PMID: 22862837 PMCID: PMC4393718 DOI: 10.1111/j.1582-4934.2012.01612.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 07/13/2012] [Indexed: 12/15/2022] Open
Abstract
Eph receptor tyrosine kinases and their ephrin ligands are involved in various signalling pathways and mediate critical steps of a wide variety of physiological and pathological processes. Increasing experimental evidence demonstrates that both Eph receptor and ephrin ligands are overexpressed in a number of human tumours, and are associated with tumour growth, invasiveness and metastasis. In this regard, the Eph/ephrin system provides the foundation for potentially exciting new targets for anticancer therapies for Eph-expressing tumours. The purpose of this review is to outline current advances in the role of Eph receptors and ephrin ligands in cancer, and to discuss novel therapeutic approaches of anticancer therapies.
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Affiliation(s)
- Hong-Qing Xi
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, China
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20
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Yamada T, Yuasa M, Masaoka T, Taniyama T, Maehara H, Torigoe I, Yoshii T, Shinomiya K, Okawa A, Sotome S. After repeated division, bone marrow stromal cells express inhibitory factors with osteogenic capabilities, and EphA5 is a primary candidate. Bone 2013; 57:343-54. [PMID: 24029132 DOI: 10.1016/j.bone.2013.08.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 08/23/2013] [Accepted: 08/29/2013] [Indexed: 01/01/2023]
Abstract
The differentiation capability of human bone marrow stromal cells (hBMSCs) is thought to deteriorate over multiple doubling processes. To clarify the deterioration mechanisms, the multilineage differentiation capabilities of short- and long-term passaged BMSCs were compared. Predictably, long-term passaged BMSCs showed reduced differentiation capacities compared to short-term passaged cells. Furthermore, a non-human primate heterotopic bone formation model demonstrated that long-term passaged BMSCs have bone formation capabilities but also exert inhibitory effects on bone formation. This finding indicated that long-term passaged BMSCs express higher levels of inhibitory factors than short-term passaged BMSCs do. Co-culture assays of short- and long-term passaged BMSCs suggested that the inhibitory signals required cell-cell contact and would therefore be expressed on the cell membrane. A microarray analysis of BMSCs identified ephrin type-A receptor 5 (EphA5) as an inhibitory factor candidate. Quantitative PCR revealed that among all members of the ephrin and Eph receptor families, only the expression of EphA5 was increased by BMSC proliferation. A gene knockdown analysis using siRNAs demonstrated that knockdown of EphA5 gene expression in long-term passaged BMSCs led to an increase in ALP mRNA expression. These results indicate that EphA5 may be a negative regulator of bone formation. A better understanding of the roles of the ephrin and Eph receptor families in hBMSCs may lead to alternative approaches for manipulating hBMSC fate. In addition, this avenue of discovery may provide new therapeutic targets and quality-control markers of the osteogenic differentiation capabilities of hBMSCs.
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Affiliation(s)
- Tsuyoshi Yamada
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan; Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo, Japan
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21
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Yu X, Wang G, Gilmore A, Yee AX, Li X, Xu T, Smith SJ, Chen L, Zuo Y. Accelerated experience-dependent pruning of cortical synapses in ephrin-A2 knockout mice. Neuron 2013; 80:64-71. [PMID: 24094103 DOI: 10.1016/j.neuron.2013.07.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
Abstract
Refinement of mammalian neural circuits involves substantial experience-dependent synapse elimination. Using in vivo two-photon imaging, we found that experience-dependent elimination of postsynaptic dendritic spines in the cortex was accelerated in ephrin-A2 knockout (KO) mice, resulting in fewer adolescent spines integrated into adult circuits. Such increased spine removal in ephrin-A2 KOs depended on activation of glutamate receptors, as blockade of the N-methyl-D-aspartate (NMDA) receptors eliminated the difference in spine loss between wild-type and KO mice. We also showed that ephrin-A2 in the cortex colocalized with glial glutamate transporters, which were significantly downregulated in ephrin-A2 KOs. Consistently, glial glutamate transport was reduced in ephrin-A2 KOs, resulting in an accumulation of synaptic glutamate. Finally, inhibition of glial glutamate uptake promoted spine elimination in wild-type mice, resembling the phenotype of ephrin-A2 KOs. Together, our results suggest that ephrin-A2 regulates experience-dependent, NMDA receptor-mediated synaptic pruning through glial glutamate transport during maturation of the mouse cortex.
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Affiliation(s)
- Xinzhu Yu
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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22
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Fujiwara H, Nishioka Y, Matsumoto H, Suginami K, Horie A, Tani H, Matsumura N, Baba T, Sato Y, Araki Y, Konishi I. Eph-ephrin A system regulates human choriocarcinoma-derived JEG-3 cell invasion. Int J Gynecol Cancer 2013; 23:576-82. [PMID: 23429488 DOI: 10.1097/igc.0b013e3182849e36] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES The Eph-ephrin system is a unique system that can induce multiple cellular responses such as cell migration, regulation of angiogenesis, and axonal guidance. Previously, the Eph-ephrin system was reported to regulate human extravillous trophoblast invasion. In this study, we examined the possible involvement of the Eph-ephrin system in the invasion of malignant gestational trophoblastic diseases using a human choriocarcinoma-derived cell line, JEG-3. METHODS The mRNA expression of class A Ephs and ephrins on JEG-3 cells was examined by reverse transcription-polymerase chain reaction. The effects of recombinant human Eph A1 (r-Eph A1) and r-ephrin A4 on the proliferation and invasion of JEG-3 cells were investigated by cell proliferation and Matrigel invasion assays. The alterations of integrin expression on JEG-3 cells in the presence of r-Eph A1 and r-ephrin A4 were investigated by flow cytometry. The induction of phosphorylation of focal adhesion kinase in JEG-3 cells by r-ephrin A4 was examined by Western blot analysis. RESULTS By reverse transcription-polymerase chain reaction, mRNAs of Eph A1, A2, and A4 and ephrin A1, A4, and A5 were detected on JEG-3 cells. In Matrigel invasion assay, both r-Eph A1 and r-ephrin A4 promoted the invasion of JEG-3 cells without affecting cell proliferation. During 24-hour culture with r-Eph A1 and r-ephrin A4, the increase in integrin α 5 expression on JEG-3 cells was observed by flow cytometry. Western blotting analysis showed that r-ephrin A4 induced dephosphorylation of focal adhesion kinase in JEG-3 cells. CONCLUSIONS These findings suggest that Eph-ephrin interaction plays some role in the regulation of choriocarcinoma invasion in cooperation with integrins.
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Affiliation(s)
- Hiroshi Fujiwara
- Department of Gynecology and Obstetrics, Faculty of Medicine, Kyoto University, Kyoto, Japan.
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23
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Dutta D, Chakraborty S, Bandyopadhyay C, Valiya Veettil M, Ansari MA, Singh VV, Chandran B. EphrinA2 regulates clathrin mediated KSHV endocytosis in fibroblast cells by coordinating integrin-associated signaling and c-Cbl directed polyubiquitination. PLoS Pathog 2013; 9:e1003510. [PMID: 23874206 PMCID: PMC3715429 DOI: 10.1371/journal.ppat.1003510] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 06/06/2013] [Indexed: 12/22/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with human dermal endothelial cell surface tyrosine kinase EphrinA2 (EphA2) and integrins (α3β1 and αVβ3) in the lipid raft (LR) region, and EphA2 regulates macropinocytic virus entry by coordinating integrin-c-Cbl associated signaling. In contrast, KSHV enters human foreskin fibroblast (HFF) cells by LR-independent clathrin mediated endocytosis. The present studies conducted to identify the key molecules regulating KSHV entry in HFF cells showed that KSHV induces association with integrins (αVβ5, αVβ3 and α3β1) and EphA2 in non-LR regions early during infection and activates EphA2, which in turn associates with phosphorylated c-Cbl, myosin IIA, FAK, Src, and PI3-K, as well as clathrin and its adaptor AP2 and effector Epsin-15 proteins. EphA2 knockdown significantly reduced these signal inductions, virus internalization and gene expression. c-Cbl knockdown ablated the c-Cbl mediated K63 type polyubiquitination of EphA2 and clathrin association with EphA2 and KSHV. Mutations in EphA2's tyrosine kinase domain (TKD) or sterile alpha motif (SAM) abolished its interaction with c-Cbl. Mutations in tyrosine kinase binding (TKB) or RING finger (RF) domains of c-Cbl resulted in very poor association of c-Cbl with EphA2 and decreased EphA2 polyubiquitination. These studies demonstrated the contributions of these domains in EphA2 and c-Cbl association, EphA2 polyubiquitination and virus-EphA2 internalization. Collectively, these results revealed for the first time that EphA2 influences the tyrosine phosphorylation of clathrin, the role of EphA2 in clathrin mediated endocytosis of a virus, and c-Cbl mediated EphA2 polyubiquitination directing KSHV entry in HFF cells via coordinated signal induction and progression of endocytic events, all of which suggest that targeting EphA2 and c-Cbl could block KSHV entry and infection.
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Affiliation(s)
- Dipanjan Dutta
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Sayan Chakraborty
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Chirosree Bandyopadhyay
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mohanan Valiya Veettil
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mairaj Ahmed Ansari
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Vivek Vikram Singh
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
- * E-mail:
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Arvanitis DN, Béhar A, Tryoen-Tóth P, Bush JO, Jungas T, Vitale N, Davy A. Ephrin B1 maintains apical adhesion of neural progenitors. Development 2013; 140:2082-92. [PMID: 23578932 DOI: 10.1242/dev.088203] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apical neural progenitors are polarized cells for which the apical membrane is the site of cell-cell and cell-extracellular matrix adhesion events that are essential for maintaining the integrity of the developing neuroepithelium. Apical adhesion is important for several aspects of the nervous system development, including morphogenesis and neurogenesis, yet the mechanisms underlying its regulation remain poorly understood. Here, we show that ephrin B1, a cell surface protein that engages in cell signaling upon binding cognate Eph receptors, controls normal morphogenesis of the developing cortex. Efnb1-deficient embryos exhibit morphological alterations of the neuroepithelium that correlate with neural tube closure defects. Using loss-of-function experiments by ex vivo electroporation, we demonstrate that ephrin B1 is required in apical progenitors (APs) to maintain their apical adhesion. Mechanistically, we show that ephrin B1 controls cell-ECM adhesion by promoting apical localization of integrin β1 and we identify ADP-ribosylation factor 6 (Arf6) as an important effector of ephrin B1 reverse signaling in apical adhesion of APs. Our results provide evidence for an important role for ephrin B1 in maintaining the structural integrity of the developing cortex and highlight the importance of tightly controlling apical cell-ECM adhesion for neuroepithelial development.
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Affiliation(s)
- Dina N Arvanitis
- Centre de Biologie du Développement, CNRS, 118 Route de Narbonne, Bât 4R3, 31062 Toulouse cedex 9, France
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Niesvizky R, Mark TM, Ward M, Jayabalan DS, Pearse RN, Manco M, Stern J, Christos PJ, Mathews L, Shore TB, Zafar F, Pekle K, Xiang Z, Ely S, Skerret D, Chen-Kiang S, Coleman M, Lane ME. Overcoming the response plateau in multiple myeloma: a novel bortezomib-based strategy for secondary induction and high-yield CD34+ stem cell mobilization. Clin Cancer Res 2013; 19:1534-46. [PMID: 23357980 DOI: 10.1158/1078-0432.ccr-12-1429] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE This phase II study evaluated bortezomib-based secondary induction and stem cell mobilization in 38 transplant-eligible patients with myeloma who had an incomplete and stalled response to, or had relapsed after, previous immunomodulatory drug-based induction. EXPERIMENTAL DESIGN Patients received up to six 21-day cycles of bortezomib plus dexamethasone, with added liposomal doxorubicin for patients not achieving partial response or better by cycle 2 or very good partial response or better (≥VGPR) by cycle 4 (DoVeD), followed by bortezomib, high-dose cyclophosphamide, and filgrastim mobilization. Gene expression/signaling pathway analyses were conducted in purified CD34+ cells after bortezomib-based mobilization and compared against patients who received only filgrastim ± cyclophosphamide. Plasma samples were similarly analyzed for quantification of associated protein markers. RESULTS The response rate to DoVeD relative to the pre-DoVeD baseline was 61%, including 39% ≥ VGPR. Deeper responses were achieved in 10 of 27 patients who received bortezomib-based mobilization; postmobilization response rate was 96%, including 48% ≥ VGPR, relative to the pre-DoVeD baseline. Median CD34+ cell yield was 23.2 × 10(6) cells/kg (median of 1 apheresis session). After a median follow-up of 46.6 months, median progression-free survival was 47.1 months from DoVeD initiation; 5-year overall survival rate was 76.4%. Grade ≥ 3 adverse events included thrombocytopenia (13%), hand-foot syndrome (11%), peripheral neuropathy (8%), and neutropenia (5%). Bortezomib-based mobilization was associated with modulated expression of genes involved in stem cell migration. CONCLUSION Bortezomib-based secondary induction and mobilization could represent an alternative strategy for elimination of tumor burden in immunomodulatory drug-resistant patients that does not impact stem cell yield.
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Affiliation(s)
- Ruben Niesvizky
- Center of Excellence for Lymphoma and Myeloma, Division of Hematology and Medical Oncology, Weill Cornell Medical College and New York Presbyterian Hospital, New York, New York 10021, USA.
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Abstract
Cancer cells rely on intercellular communication throughout the different stages of their transformation and progression into metastasis. They do so by co-opting different processes such as cell-cell junctions, growth factors, receptors, and vesicular release. Initially characterized in neuronal and vascular tissues, Ephs and Ephrins, the largest family of receptor tyrosine kinases, comprised of two classes (i.e., A and B types), is increasingly scrutinized by cancer researchers. These proteins possess the particular features of both the receptors and ligands being membrane-bound which, via mandatory direct cell-cell interactions, undergo a bidirectional signal transduction initiated from both the receptor and the ligand. Following cell-cell interactions, Ephs/Ephrins behave as guidance molecules which trigger both repulsive and attractive signals, so as to direct the movement of cells through their immediate microenvironment. They also direct processes which include sorting and positioning and cytoskeleton rearrangements, thus making them perfect candidates for the control of the metastatic process. In fact, the role of Ephs and Ephrins in cancer progression has been demonstrated for many of the family members and they, surprisingly, have both tumor promoter and suppressor functions in different cellular contexts. They are also able to coordinate between multiple processes including cell survival, proliferation, differentiation, adhesion, motility, and invasion. This review is an attempt to summarize the data available on these Ephs/Ephrins' biological functions which contribute to the onset of aggressive cancers. I will also provide an overview of the factors which could explain the functional differences demonstrated by Ephs and Ephrins at different stages of tumor progression and whose elucidation is warranted for any future therapeutic targeting of this signaling pathway in cancer metastasis.
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Nievergall E, Lackmann M, Janes PW. Eph-dependent cell-cell adhesion and segregation in development and cancer. Cell Mol Life Sci 2012; 69:1813-42. [PMID: 22204021 PMCID: PMC11114713 DOI: 10.1007/s00018-011-0900-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/06/2011] [Accepted: 11/28/2011] [Indexed: 01/23/2023]
Abstract
Numerous studies attest to essential roles for Eph receptors and their ephrin ligands in controlling cell positioning and tissue patterning during normal and oncogenic development. These studies suggest multiple, sometimes contradictory, functions of Eph-ephrin signalling, which under different conditions can promote either spreading and cell-cell adhesion or cytoskeletal collapse, cell rounding, de-adhesion and cell-cell segregation. A principle determinant of the balance between these two opposing responses is the degree of receptor/ligand clustering and activation. This equilibrium is likely altered in cancers and modulated by somatic mutations of key Eph family members that have emerged as candidate cancer markers in recent profiling studies. In addition, cross-talk amongst Ephs and with other signalling pathways significantly modulates cell-cell adhesion, both between and within Eph- and ephrin-expressing cell populations. This review summarises our current understanding of how Eph receptors control cell adhesion and morphology, and presents examples demonstrating the importance of these events in normal development and cancer.
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Affiliation(s)
- Eva Nievergall
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
- Present Address: Haematology Department, SA Pathology, Frome Road, Adelaide, SA 5000 Australia
| | - Martin Lackmann
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
| | - Peter W. Janes
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
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Kaposi's sarcoma-associated herpesvirus interacts with EphrinA2 receptor to amplify signaling essential for productive infection. Proc Natl Acad Sci U S A 2012; 109:E1163-72. [PMID: 22509030 DOI: 10.1073/pnas.1119592109] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), etiologically associated with Kaposi's sarcoma, uses integrins (α3β1, αVβ3, and αVβ5) and associated signaling to enter human dermal microvascular endothelial cells (HMVEC-d), an in vivo target of infection. KSHV infection activated c-Cbl, which induced the selective translocation of KSHV into lipid rafts (LRs) along with the α3β1, αVβ3, and xCT receptors, but not αVβ5. LR-translocated receptors were monoubiquitinated, leading to productive macropinocytic entry, whereas non-LR-associated αVβ5 was polyubiquitinated, leading to clathrin-mediated entry that was targeted to lysosomes. Because the molecule(s) that integrate signal pathways and productive KSHV macropinocytosis were unknown, we immunoprecipitated KSHV-infected LR fractions with anti-α3β1 antibodies and analyzed them by mass spectrometry. The tyrosine kinase EphrinA2 (EphA2), implicated in many cancers, was identified in this analysis. EphA2 was activated by KSHV. EphA2 was also associated with KSHV and integrins (α3β1 and αVβ3) in LRs early during infection. Preincubation of virus with soluble EphA2, knockdown of EphA2 by shRNAs, or pretreatment of cells with anti-EphA2 monoclonal antibodies or tyrosine kinase inhibitor dasatinib significantly reduced KSHV entry and gene expression. EphA2 associates with c-Cbl-myosin IIA and augmented KSHV-induced Src and PI3-K signals in LRs, leading to bleb formation and macropinocytosis of KSHV. EphA2 shRNA ablated macropinocytosis-associated signaling events, virus internalization, and productive nuclear trafficking of KSHV DNA. Taken together, these studies demonstrate that the EphA2 receptor acts as a master assembly regulator of KSHV-induced signal molecules and KSHV entry in endothelial cells and suggest that the EphA2 receptor is an attractive target for controlling KSHV infection.
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Coate TM, Raft S, Zhao X, Ryan AK, Crenshaw EB, Kelley MW. Otic mesenchyme cells regulate spiral ganglion axon fasciculation through a Pou3f4/EphA4 signaling pathway. Neuron 2012; 73:49-63. [PMID: 22243746 DOI: 10.1016/j.neuron.2011.10.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2011] [Indexed: 10/14/2022]
Abstract
Peripheral axons from auditory spiral ganglion neurons (SGNs) form an elaborate series of radially and spirally oriented projections that interpret complex aspects of the auditory environment. However, the developmental processes that shape these axon tracts are largely unknown. Radial bundles are comprised of dense SGN fascicles that project through otic mesenchyme to form synapses within the cochlea. Here, we show that radial bundle fasciculation and synapse formation are disrupted when Pou3f4 (DFNX2) is deleted from otic mesenchyme. Further, we demonstrate that Pou3f4 binds to and directly regulates expression of Epha4, Epha4⁻/⁻ mice present similar SGN defects, and exogenous EphA4 promotes SGN fasciculation in the absence of Pou3f4. Finally, Efnb2 deletion in SGNs leads to similar fasciculation defects, suggesting that ephrin-B2/EphA4 interactions are critical during this process. These results indicate a model whereby Pou3f4 in the otic mesenchyme establishes an Eph/ephrin-mediated fasciculation signal that promotes inner radial bundle formation.
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Affiliation(s)
- Thomas M Coate
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
Great strides have been made regarding our understanding of the processes and signaling events influenced by Eph/ephrin signaling that play a role in cell adhesion and cell movement. However, the precise mechanisms by which these signaling events regulate cell and tissue architecture still need further resolution. The Eph/ephrin signaling pathways and the ability to regulate cell-cell adhesion and motility constitutes an impressive system for regulating tissue separation and morphogenesis (Pasquale, 2005, 2008 [1,2]). Moreover, the de-regulation of this signaling system is linked to the promotion of aggressive and metastatic tumors in humans [2]. In the following section, we discuss some of the interesting mechanisms by which ephrins can signal through their own intracellular domains (reverse signaling) either independent of forward signaling or in addition to forward signaling through a cognate receptor. In this review we discuss how ephrins (Eph ligands) "reverse signal" through their intracellular domains to affect cell adhesion and movement, but the focus is on modes of action that are independent of SH2 and PDZ interactions.
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Affiliation(s)
- Ira O Daar
- Laboratory of Cell & Developmental Signaling, National Cancer Institute-Frederick, Frederick, MD 21702, USA.
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Singh A, Winterbottom E, Daar IO. Eph/ephrin signaling in cell-cell and cell-substrate adhesion. Front Biosci (Landmark Ed) 2012; 17:473-97. [PMID: 22201756 DOI: 10.2741/3939] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cell-cell and cell-matrix adhesion are critical processes for the formation and maintenance of tissue patterns during development, as well as control of invasion and metastasis of cancer cells. Although great strides have been made regarding our understanding of the processes that play a role in cell adhesion and cell movement, the precise mechanisms by which diverse signaling events regulate cell and tissue architecture are poorly understood. One group of cell surface molecules, Eph receptor tyrosine kinases, and their membrane-bound ligands, ephrins, are key regulators in these processes. It is the ability of Eph/ephrin signaling pathways to regulate cell-cell adhesion and motility that establishes this family as a formidable system for regulating tissue separation and morphogenesis. Moreover, the de-regulation of this signaling system is linked to the promotion of more aggressive and metastatic tumors in humans.
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Affiliation(s)
- Arvinder Singh
- Laboratory of Cell and Developmental Signaling, National Cancer Institute-Frederick, Frederick, Maryland 21702, USA
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Xu NJ, Henkemeyer M. Ephrin reverse signaling in axon guidance and synaptogenesis. Semin Cell Dev Biol 2011; 23:58-64. [PMID: 22044884 DOI: 10.1016/j.semcdb.2011.10.024] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/17/2011] [Indexed: 01/17/2023]
Abstract
Axon-cell and axon-dendrite contact is a highly regulated process necessary for the formation of precise neural circuits and a functional neural network. Eph-ephrin interacting molecules on the membranes of axon nerve terminals and target dendrites act as bidirectional ligands/receptors to transduce signals into both the Eph-expressing and ephrin-expressing cells to regulate cytoskeletal dynamics. In particular, recent evidence indicates that ephrin reverse signal transduction events are important in controlling both axonal and dendritic elaborations of neurons in the developing nervous system. Here we review how ephrin reverse signals are transduced into neurons to control maturation of axonal pre-synaptic and dendritic post-synaptic structures.
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Affiliation(s)
- Nan-Jie Xu
- Department of Developmental Biology, Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Miao H, Wang B. EphA receptor signaling--complexity and emerging themes. Semin Cell Dev Biol 2011; 23:16-25. [PMID: 22040915 DOI: 10.1016/j.semcdb.2011.10.013] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 10/17/2011] [Indexed: 01/09/2023]
Abstract
The impact of Eph and ephrin signaling on cell behavior is complex and highly context dependent. Forward signaling initiated by Eph receptor activation and reverse signaling initiated by ephrin activation often mediate opposite effects. The apparent ligand-independent functions of Eph receptors recognized recently add another layer of complexity. This review will attempt to sort out the information generated recently on signaling by the A subfamily of Eph receptors and ephrin ligands. We will focus on EphA/ephrin-A signaling in the context of several physiological and disease processes, where new progresses have been made lately and unifying themes are emerging amid previous confusions. For more comprehensive survey of literature on Eph/ephrin signaling pathways and networks, readers are referred to outstanding reviews both in this volume and in other recent publications.
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Affiliation(s)
- Hui Miao
- Rammelkamp Center for Research, MetroHealth Campus, Case Western Reserve University School of Medicine, 2500 MetroHealth Drive, Cleveland, OH 44109, USA.
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Suetterlin P, Marler KM, Drescher U. Axonal ephrinA/EphA interactions, and the emergence of order in topographic projections. Semin Cell Dev Biol 2011; 23:1-6. [PMID: 22040913 DOI: 10.1016/j.semcdb.2011.10.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 10/17/2011] [Indexed: 12/31/2022]
Abstract
In the classical view of axon guidance, neurons send out axons which are endowed with guidance receptors enabling them to find their (distant) target areas by an interaction with their ligands expressed in specific spatio-temporal patterns along their pathways and in their target area. However, this view has recently been confounded by more detailed analyses of, for example, the expression patterns of EphAs and ephrinAs in the retinotectal projection. Here ephrinA 'ligands' are expressed not only in the target area but also on the projecting RGC axons, and EphA 'receptors' not only on retinal ganglion cell (RGC) axons but also in the target area itself. This review describes the on-going functional characterisation of the surprising co-expression of ephrinAs and EphAs on retinal ganglion cell (RGC) axons and other cell types. It also investigates the function of ephrinAs as receptors and describes their interaction with co-receptors involved in mediating this function.
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Affiliation(s)
- Philipp Suetterlin
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
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Eph receptors and ephrins in neuron-astrocyte communication at synapses. Glia 2011; 59:1567-78. [DOI: 10.1002/glia.21226] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 07/05/2011] [Indexed: 12/24/2022]
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Poopalasundaram S, Marler KJM, Drescher U. EphrinA6 on chick retinal axons is a key component for p75(NTR)-dependent axon repulsion and TrkB-dependent axon branching. Mol Cell Neurosci 2011; 47:131-6. [PMID: 21463686 PMCID: PMC4038918 DOI: 10.1016/j.mcn.2011.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 03/24/2011] [Accepted: 03/25/2011] [Indexed: 11/18/2022] Open
Abstract
A characteristic of the ephrin/Eph family is their capacity for bi-directional signalling. This means that an ephrin, for example, can function either as a ligand for an Eph 'receptor', or as a receptor for an Eph 'ligand'. A system in which this phenomenon is well studied is the retinotectal projection in which the guidance of retinal ganglion cell (RGC) axons to their target area in the tectum is controlled by both Ephs and ephrins expressed in gradients in both the retina and tectum. Here we have analysed the receptor function of ephrinAs on RGC axons in further detail by focussing on ephrinA6, which is the most strongly expressed ephrinA in the chick retina. EphrinAs are GPI-anchored proteins and therefore require the interaction with transmembrane proteins to exert this receptor function. Previous work has shown that ephrinAs interact on RGC axons in cis with the neurotrophin receptors p75(NTR) and TrkB. P75(NTR) then was shown to be necessary for the repulsion of ephrinA-expressing RGC axons from an EphA substrate and for the downregulation of axon branching. In turn, an interaction of ephrinAs with TrkB as well as an increase in axonal ephrinA expression augments the axon branch-promoting activity of TrkB. We now show that ephrinA6 is the necessary ephrinA component of the repulsive ephrinA/p75(NTR) receptor complex on chick RGC axons as axons lacking ephrinA6 no longer avoid an EphA matrix in stripe assay experiments. We also demonstrate that the branch-promoting activity of TrkB is dependent on ephrinA6 as a knockdown of ephrinA6 renders RGC axons insensitive to BDNF, the high affinity ligand for TrkB. In sum our data further strengthen the hypothesis that a fine-tuned interplay of ephrinAs with p75(NTR) and TrkB is important for the guidance and branching of RGC axons.
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Affiliation(s)
- Subathra Poopalasundaram
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, Guy's Campus, London SE11UL, UK.
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Cell-cell communication mimicry with poly(ethylene glycol) hydrogels for enhancing beta-cell function. Proc Natl Acad Sci U S A 2011; 108:6380-5. [PMID: 21464290 DOI: 10.1073/pnas.1014026108] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A biomimetic hydrogel platform was designed to signal encapsulated cells using immobilized cell-cell communication cues, with a focus on enhancing the survival and function of encapsulated pancreatic β-cells to treat type 1 diabetes. When MIN6 cells, a pancreatic β-cell line, were encapsulated in poly(ethylene glycol) (PEG) hydrogels, their survival and glucose responsiveness to insulin were highly dependent on the cell-packing density. A minimum packing density of 10(7) cells/mL was necessary to maintain the survival of encapsulated β-cells without the addition of material functionalities (e.g., cell adhesion ligands). While single cell suspensions can improve diffusion-limited mass transfer, direct cell-cell interactions are limited. Thus, thiolated EphA5-Fc receptor and ephrinA5-Fc ligand were conjugated into PEG hydrogels via a thiol-acrylate photopolymerization to render an otherwise inert PEG hydrogel bioactive. The biomimetic hydrogels presented here can provide crucial cell-cell communication signals for dispersed β-cells and improve their survival and proliferation. Together with the cell-adhesive peptide RGDS, the immobilized fusion proteins (EphA5-Fc and ephrinA5-Fc) synergistically increased the survival of both MIN6 β-cells and dissociated islet cells, both at a very low cell-packing density (< 2 × 10(6) cells/mL). This unique gel platform demonstrates new strategies for tailoring biomimetic environments to enhance the encapsulation of cells that require cell-cell contact to survive and function.
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An insight into the sequential, structural and phylogenetic properties of banana 1-aminocyclopropane-1-carboxylate synthase 1 and study of its interaction with pyridoxal-5'-phosphate and aminoethoxyvinylglycine. J Biosci 2011; 35:281-94. [PMID: 20689184 DOI: 10.1007/s12038-010-0032-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In banana, ethylene production for ripening is accompanied by a dramatic increase in 1-aminocyclopropane-1-carboxylate (ACC) content, transcript level of Musa acuminata ACC synthase 1 (MA-ACS1) and the enzymatic activity of ACC synthase 1 at the onset of the climacteric period. MA-ACS1 catalyses the conversion of S-adenosyl-L-methionine (SAM) to ACC, the key regulatory step in ethylene biosynthesis. Multiple sequence alignments of 1-aminocyclopropane-1-carboxylate synthase (ACS) amino acid sequences based on database searches have indicated that MA-ACS1 is a highly conserved protein across the plant kingdom. This report describes an in silico analysis to provide the first important insightful information about the sequential, structural and phylogenetic characteristics of MA-ACS1. The three-dimensional structure of MA-ACS1, constructed based on homology modelling, in combination with the available data enabled a comparative mechanistic analysis of MA-ACS1 to explain the catalytic roles of the conserved and non-conserved active site residues. We have further demonstrated that, as in apple and tomato, banana- ACS1 (MA-ACS1) forms a homodimer and a complex with cofactor pyridoxal-5'-phosphate (PLP) and inhibitor aminoethoxyvinylglycine (AVG). We have also predicted that the residues from the PLP-binding pocket, essential for ligand binding, are mostly conserved across the MA-ACS1 structure and the competitive inhibitor AVG binds at a location adjacent to PLP.
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Abstract
The development, homeostasis, and regeneration of complex organ systems require extensive cell-cell communication to ensure that different cells proliferate, migrate, differentiate, assemble, and function in a coordinated and timely fashion. Eph receptor tyrosine kinases and their ephrin ligands are critical regulators of cell contact-dependent signaling and patterning. Eph/ephrin binding can lead to very diverse biological readouts such as adhesion versus repulsion, or increased versus decreased motility. Accordingly, depending on cell type and context, a limited and conserved set of receptor-ligand interactions is translated into a large variety of downstream signaling processes. Recent evidence indicates that the endocytosis of Eph/ephrin molecules, together with the internalization of various associated tissue-specific effectors, might be one of the key principles responsible for such highly diverse and adaptable biological roles. Here, we summarize recent insights into Eph/ephrin signaling and endocytosis in three biological systems; i.e., the brain, intestine, and vasculature.
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Affiliation(s)
- Mara E Pitulescu
- Department of Tissue Morphogenesis, Max-Planck-Institute for Molecular Biomedicine, and Faculty of Medicine, University of Münster, Münster, Germany
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Ting MJ, Day BW, Spanevello MD, Boyd AW. Activation of ephrin A proteins influences hematopoietic stem cell adhesion and trafficking patterns. Exp Hematol 2010; 38:1087-98. [PMID: 20655977 DOI: 10.1016/j.exphem.2010.07.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 07/09/2010] [Accepted: 07/14/2010] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine if Eph receptors and ephrins can modulate the homing of hematopoietic cells in a murine bone marrow transplantation model. MATERIALS AND METHODS EphA and ephrin A gene expression by mouse hematopoietic stem cells and the progenitor cell line FDCP-1 was determined by real-time reverse transcription polymerase chain reaction and flow cytometry. The effect of ephrin A activation on adhesion of hematopoietic progenitors was determined by in vitro adhesion assays in which cells were exposed to fibronectin or vascular cell adhesion molecule-1 (VCAM-1) and an increasing gradient of immobilized EphA3-Fc. Adhesion to fibronectin and VCAM-1 was further investigated using soluble preclustered EphA3-Fc. We used soluble unclustered EphA3-Fc as an antagonist to block endogenous EphA-ephrin A interactions in vivo. The effect of injecting soluble EphA3-Fc on the mobilization of hematopoietic progenitor cells was examined. We determined the effect on short-term homing by pretreating bone marrow cells with EphA3-Fc or the control IgG before infusion into lethally irradiated mice. RESULTS Preclustered and immobilized EphA3-Fc increased adhesion of progenitor cells and FDCP-1 to fibronectin and VCAM-1 (1.6- to 2-fold higher adhesion; p < 0.05) relative to control (0 μ/cm(2) EphA3-Fc extracellular molecule alone). Injection of the antagonist soluble EphA3-Fc increased progenitor cell and colony-forming unit-spleen cells in the peripheral blood (42% greater colony-forming unit in culture; p < 0.05, 3.8-fold higher colony-forming unit-spleen) relative to control. CONCLUSION Treating bone marrow cells with EphA3-Fc resulted in a reduction by 31% in donor stem cells homing to the bone marrow and accumulation of donor cells in recipient spleens (50% greater than control) and greater recovery of donor stem cells from the peripheral blood.
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Affiliation(s)
- Michael J Ting
- Leukaemia Foundation of Queensland Research Unit, Queensland Institute of Medical Research, Brisbane, Australia.
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McCarron JK, Stringer BW, Day BW, Boyd AW. Ephrin expression and function in cancer. Future Oncol 2010; 6:165-76. [PMID: 20021216 DOI: 10.2217/fon.09.146] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ephrins are cell membrane-associated signaling proteins bound by transmembrane Eph receptors on juxtaposed cells. Eph-ephrin interactions result in bidirectional signaling within both receptor- and ligand-bearing cells, with diverse consequences for cell morphology and behavior. Such interactions are especially important during early vertebrate development, and growing evidence has revealed equally important roles in adult-tissue homeostasis. As for the Eph receptors, abnormal expression of ephrins is associated with disease, especially cancer. The ephrins have received less attention than the Ephs in the literature, owing, in part, to their later discovery and that they are fewer in number. Here, we attempt to redress this imbalance and provide an 'ephrin-centric' discussion of the expression and function of ephrins in cancer.
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Affiliation(s)
- Jennifer K McCarron
- Leukaemia Foundation Research Unit, Queensland Institute of Medical Research, P.O. Royal Brisbane Hospital, Queensland, 4029, Brisbane, Australia.
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Kalinski T, Röpke A, Sel S, Kouznetsova I, Röpke M, Roessner A. Down-regulation of ephrin-A5, a gene product of normal cartilage, in chondrosarcoma. Hum Pathol 2009; 40:1679-85. [DOI: 10.1016/j.humpath.2009.03.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/24/2009] [Accepted: 03/21/2009] [Indexed: 12/20/2022]
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Reverse signaling by glycosylphosphatidylinositol-linked Manduca ephrin requires a SRC family kinase to restrict neuronal migration in vivo. J Neurosci 2009; 29:3404-18. [PMID: 19295147 DOI: 10.1523/jneurosci.5464-08.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Reverse signaling via glycosylphosphatidylinositol (GPI)-linked Ephrins may help control cell proliferation and outgrowth within the nervous system, but the mechanisms underlying this process remain poorly understood. In the embryonic enteric nervous system (ENS) of the moth Manduca sexta, migratory neurons forming the enteric plexus (EP cells) express a single Ephrin ligand (GPI-linked MsEphrin), whereas adjacent midline cells that are inhibitory to migration express the cognate receptor (MsEph). Knocking down MsEph receptor expression in cultured embryos with antisense morpholino oligonucleotides allowed the EP cells to cross the midline inappropriately, consistent with the model that reverse signaling via MsEphrin mediates a repulsive response in the ENS. Src family kinases have been implicated in reverse signaling by type-A Ephrins in other contexts, and MsEphrin colocalizes with activated forms of endogenous Src in the leading processes of the EP cells. Pharmacological inhibition of Src within the developing ENS induced aberrant midline crossovers, similar to the effect of blocking MsEphrin reverse signaling. Hyperstimulating MsEphrin reverse signaling with MsEph-Fc fusion proteins induced the rapid activation of endogenous Src specifically within the EP cells, as assayed by Western blots of single embryonic gut explants and by whole-mount immunostaining of cultured embryos. In longer cultures, treatment with MsEph-Fc caused a global inhibition of EP cell migration and outgrowth, an effect that was prevented by inhibiting Src activation. These results support the model that MsEphrin reverse signaling induces the Src-dependent retraction of EP cell processes away from the enteric midline, thereby helping to confine the neurons to their appropriate pathways.
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Scicolone G, Ortalli AL, Carri NG. Key roles of Ephs and ephrins in retinotectal topographic map formation. Brain Res Bull 2009; 79:227-47. [PMID: 19480983 DOI: 10.1016/j.brainresbull.2009.03.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 02/16/2009] [Accepted: 03/24/2009] [Indexed: 01/06/2023]
Abstract
Cellular and molecular mechanisms involved in the development of topographic ordered connections in the central nervous system (CNS) constitute a key issue in neurobiology because neural connectivities are the base of the CNS normal function. We discuss the roles of the Eph/ephrin system in the establishment of retinotopic projections onto the tectum/colliculus, the most detailed studied model of topographic mapping. The expression patterns of Ephs and ephrins in opposing gradients both in the retina and the tectum/colliculus, label the local addresses on the target and give specific sensitivities to growth cones according to their topographic origin in the retina. We postulate that the highest levels of these gradients could signal both the entry as well as the limiting boundaries of the target. Since Ephs and ephrins are membrane-bound molecules, they may function as both receptors and ligands producing repulsive or attractant responses according to their microenvironment and play central roles in a variety of developmental events such as axon guidance, synapse formation and remodeling. Due to different experimental approaches and the inherent species-specific differences, some results appear contradictory and should be reanalyzed. Nevertheless, these studies about the roles of the Eph/ephrin system in retinotectal/collicular mapping support general principles in order to understand CNS development and could be useful to design regeneration therapies.
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Affiliation(s)
- Gabriel Scicolone
- Institute of Cell Biology and Neuroscience "Prof. E. De Robertis", School of Medicine, University of Buenos Aires, 1121 Buenos Aires, Argentina.
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Abstract
Toward understanding topographically specific branching of retinal axons in their target area, we have studied the interaction between neurotrophin receptors and members of the Eph family. TrkB and its ligand BDNF are uniformly expressed in the retina and tectum, respectively, and exert a branch-promoting activity, whereas EphAs and ephrinAs are expressed in gradients in retina and tectum and can mediate a suppression of axonal branching. We have identified a novel cis interaction between ephrinA5 and TrkB on retinal ganglion cell axons. TrkB interacts with ephrinA5 via its second cysteine-rich domain (CC2), which is necessary and sufficient for binding to ephrinA5. Their functional interaction is twofold: ephrinA5 augments BDNF-promoted retinal axon branching in the absence of its activator EphA7-Fc, whereas EphA7-Fc application abolishes branching in a local and concentration-dependent manner. The importance of TrkB in this process is shown by the fact that overexpression of an isolated TrkB-CC2 domain interfering with the ephrinA/TrkB interaction abolishes this regulatory interplay, whereas knockdown of TrkB via RNA interference diminishes the ephrinA5-evoked increase in branching. The ephrinA/Trk interaction is neurotrophin induced and specifically augments the PI-3 kinase/Akt pathway generally known to be involved in the promotion of branching. In addition, ephrinAs/TrkB modulate axon branching and also synapse formation of hippocampal neurons. Our findings uncover molecular mechanisms of how spatially restricted axon branching can be achieved by linking globally expressed branch-promoting with differentially expressed branch-suppressing activities. In addition, our data suggest that growth factors and the EphA-ephrinA system interact in a way that affects axon branching and synapse development.
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Lim YS, McLaughlin T, Sung TC, Santiago A, Lee KF, O'Leary DDM. p75(NTR) mediates ephrin-A reverse signaling required for axon repulsion and mapping. Neuron 2008; 59:746-58. [PMID: 18786358 DOI: 10.1016/j.neuron.2008.07.032] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 03/07/2008] [Accepted: 07/21/2008] [Indexed: 01/08/2023]
Abstract
Reverse signaling by ephrin-As upon binding EphAs controls axon guidance and mapping. Ephrin-As are GPI-anchored to the membrane, requiring that they complex with transmembrane proteins that transduce their signals. We show that the p75 neurotrophin receptor (NTR) serves this role in retinal axons. p75(NTR) and ephrin-A colocalize within caveolae along retinal axons and form a complex required for Fyn phosphorylation upon binding EphAs, activating a signaling pathway leading to cytoskeletal changes. In vitro, retinal axon repulsion to EphAs by ephrin-A reverse signaling requires p75(NTR), but repulsion to ephrin-As by EphA forward signaling does not. Constitutive and retina-specific p75(NTR) knockout mice have aberrant anterior shifts in retinal axon terminations in superior colliculus, consistent with diminished repellent activity mediated by graded ephrin-A reverse signaling induced by graded collicular EphAs. We conclude that p75(NTR) is a signaling partner for ephrin-As and the ephrin-A- p75(NTR) complex reverse signals to mediate axon repulsion required for guidance and mapping.
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Affiliation(s)
- Yoo-Shick Lim
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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Holen HL, Shadidi M, Narvhus K, Kjøsnes O, Tierens A, Aasheim HC. Signaling through ephrin-A ligand leads to activation of Src-family kinases, Akt phosphorylation, and inhibition of antigen receptor-induced apoptosis. J Leukoc Biol 2008; 84:1183-91. [PMID: 18593733 DOI: 10.1189/jlb.1207829] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Eph receptor tyrosine kinases and ephrins play important roles in diverse biological processes such as migration, adhesion, and angiogenesis. Forward and reverse signaling has been reported in receptor- and ligand-bearing cells. The ligands can be divided into the transmembrane ephrin-B family and the GPI-anchored ephrin-A family. Here, we show expression of ephrin-A ligands on CD4+ T cells cultured in medium with human serum and the T cell line Jurkat TAg and on cells isolated from patients with T cell lymphomas and T cell leukemias. Functional role and identification of proteins involved in ephrin-A signaling were investigated here in the T cell line Jurkat TAg. Signaling through ephrin-A induces phosphorylation of several proteins, including the Src kinases Lck and Fyn. In addition, PI-3K is activated, shown by induced phosphorylation of the Akt kinase. An ephrin-A signaling complex could be isolated, containing several phosphorylated proteins including Lck and Fyn. Interestingly, we show that signaling through ephrin-A in Jurkat TAg cells, initiated by interaction with the EphA2 receptor, leads to inhibition of activation-induced cell death. To conclude, ephrin-A signaling in Jurkat TAg cells leads to induced phosphorylation of several proteins including Lck, Fyn, and Akt. A consequence of ephrin-A signaling is inhibition of antigen receptor-induced apoptosis.
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Reverse signaling via a glycosyl-phosphatidylinositol-linked ephrin prevents midline crossing by migratory neurons during embryonic development in Manduca. J Neurosci 2008; 28:3846-60. [PMID: 18400884 DOI: 10.1523/jneurosci.5691-07.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have investigated whether reverse signaling via a glycosyl-phosphatidylinositol (GPI)-linked ephrin controls the behavior of migratory neurons in vivo. During the formation of the enteric nervous system (ENS) in the moth Manduca, approximately 300 neurons [enteric plexus (EP) cells] migrate onto the midgut via bilaterally paired muscle bands but avoid adjacent midline regions. As they migrate, the EP cells express a single ephrin ligand (MsEphrin; a GPI-linked ligand), whereas the midline cells express the corresponding Eph receptor (MsEph). Blocking endogenous MsEphrin-MsEph receptor interactions in cultured embryos resulted in aberrant midline crossing by the neurons and their processes. In contrast, activating endogenous MsEphrin on the EP cells with dimeric MsEph-Fc constructs inhibited their migration and outgrowth, supporting a role for MsEphrin-dependent reverse signaling in this system. In short-term cultures, blocking endogenous MsEph receptors allowed filopodia from the growth cones of the neurons to invade the midline, whereas activating neuronal MsEphrin led to filopodial retraction. MsEphrin-dependent signaling may therefore guide the migratory enteric neurons by restricting the orientation of their leading processes. Knocking down MsEphrin expression in the EP cells with morpholino antisense oligonucleotides also induced aberrant midline crossing, consistent with the effects of blocking endogenous MsEphrin-MsEph interactions. Unexpectedly, this treatment enhanced the overall extent of migration, indicating that MsEphrin-dependent signaling may also modulate the general motility of the EP cells. These results demonstrate that MsEphrin-MsEph receptor interactions normally prevent midline crossing by migratory neurons within the developing ENS, an effect that is most likely mediated by reverse signaling through this GPI-linked ephrin ligand.
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Abstract
Bidirectional signaling has emerged as an important signature by which Ephs and ephrins control biological functions. Eph/ephrin signaling participates in a wide spectrum of developmental processes, and cross-regulation with other communication pathways lies at the heart of the complexity underlying their function in vivo. Here, we review in vitro and in vivo data describing molecular, functional, and genetic interactions between Eph/ephrin and other cell surface signaling pathways. The complexity of Eph/ephrin function is discussed in terms of the pathways that regulate Eph/ephrin signaling and also the pathways that are regulated by Eph/ephrin signaling.
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Affiliation(s)
- Dina Arvanitis
- Université de Toulouse, Centre de Biologie du Développement, 31062 Toulouse cedex 9, France
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Reber M, Hindges R, Lemke G. Eph receptors and ephrin ligands in axon guidance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 621:32-49. [PMID: 18269209 DOI: 10.1007/978-0-387-76715-4_3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael Reber
- INSERM U.575, Centre de Neurochimie, 5, rue Blaise Pascal, 67084 Strasbourg, France.
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