Mammalian Neurogenesis

Lead Research Organisation: MRC Clinical Sciences Centre

Abstract

The recent scientific achievement of DNA sequencing of all genetic information encoded in the genes of the human chromosomes, but also those of other organisms, has left us with the next challenging question: What is the function of each gene? and which set of genes (molecular mechanisms) govern embryonic development and the physiological functions of the organism and how their malfunction causes disease?||The research focus of the Mammalian Neurogenesis group falls within the area of the above objective: specifically, the identification and characterisation of genes and gene networks (or pathways) responsible for the formation the early mammalian embryo tissues such as the endoderm which will give rise to organs including lung, liver and pancreas. We identified the new gene Arkadia and showed that it is part of the TGF-beta signalling network and that mutations in it lead to lethality in the embryo and birth defects. We are also following our recent evidence that Arkadia like TGF-beta signalling is involved in cancer.||In addition, our group (Mammalian Neurogenesis) works on the development of nervous system. We studied the SOX gene family of transcription factors and showed that their loss causes neurological disorders such as epilepsy. We now study the role of TGF-beta network in the nervous system, as we identified Arkadia2 another Arkadia like gene with a role in motor neuron disease.

Technical Summary

Objectives: To understand the role of TGF-beta signalling in patterning during gastrulation (A) CNS development (B) and disease.||Experimental strategy and significance: TGF-beta signalling controls a diverse set of cellular processes, including cell proliferation, differentiation, apoptosis, and specification of developmental fate in vertebrate and invertebrate species. Disruption of signalling leads to developmental abnormalities and disease, including cancer. In recent years, tremendous progress has been made in the elucidation of how cells sense and transduce TFG-beta signals. Activin and Nodal are two key TGF-beta morphogens in vertebrate development. The role of intracellular regulators of Nodal signalling in development and embryonic cells is not understood, and little is known about ubiquitination and proteasome-mediated degradation of the activated Smads.||We have identified and shown that Arkadia, a RING domain ubiquitin ligase, enhances Nodal signalling and is essential for organizer/node induction and anterior/head development in vertebrates (Episkopou et al 2001; and Niederlander et al 2001). We use a combination of techniques such as ES cells, mouse genetics, chimaeras, and biochemistry to derive our results. We found that that Arkadia functions by degrading repressed TGF-beta effector complexes consisting of phosphorylated Smads (effectors) blocked by SnoN/Ski (nuclear co-repressors) (Mavrakis et al 2007; Nagano et al 2007 and Levy et al 2007).||As TGF-beta signalling has been linked to cancers and genetic diseases, our group is conducting extensive sequencing of Arkadia from colon tumours derived from human patients to identify mutation associated with the disease. In addition, we are generating mouse animal models carrying Arkadia null cells in various organs including the gut to assay their tendency to develop tumours. Such animal models would be useful for understanding tumourigenesis and for developing therapies.||In addition, our group studies aspects of the development of the central nervous system. The SOX family of transcription factors has emerged as a major group of developmental regulators in the brain, but their exact roles are not well known. We have previously shown that SOX1 is essential for the terminal differentiation of lens fibres and the activation of gamma-crystallins, and that its loss causes cataracts (Nishiguchi et al 1998). In addition, we showed that SOX1 is essential for the development of striatal neurons, the lack of which is associated with epilepsy (Malas et al 2003; and Ekonomou et al 2005).||Currently, we discovered a highly homologous second Arkadia-like protein, Arkadia2. Arkadia2 is expressed specifically in the nervous system and it seems that affects various aspects of TGF-beta signalling as well. Arkadia2 null mice display a neural phenotype associated with connectivity between motor neurons and muscles of the limb and diaphragm. The above findings provide evidence that the TGF-beta pathway plays role in neuromuscular connectivity, which was not known before.||We also carry work in ES cells developing assays to differentiate them in vitro towards endoderm, which contains the precursors of all organs such as liver, pancreas and lung. In addition we differentiate ES cells towards motor neurons and study the Arkadia2 deficiency. The above research provides the basis for future therapeutic strategies, those that involve the use of stem cell and tissue replacement therapies, but also supplies the basis to develop and test novel therapeutic strategies.

Publications


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Bravou V (2009) TGF-beta repressors SnoN and Ski are implicated in human colorectal carcinogenesis. in Cellular oncology : the official journal of the International Society for Cellular Oncology
Donner AL (2007) Pax6 is misexpressed in Sox1 null lens fiber cells. in Gene expression patterns : GEP
Episkopou V (2005) SOX2 functions in adult neural stem cells. in Trends in neurosciences
Graf D (2001) Evolutionary conservation, developmental expression, and genomic mapping of mammalian Twisted gastrulation. in Mammalian genome : official journal of the International Mammalian Genome Society
 
Description BBSRC Project Grant (Functional analysis of Arkadia2, a novel ubiquitin ligase, expressed specifically in neurons)
Amount £329,552 (GBP)
Funding ID BB/G00577X/1 and BB/G00577X/2 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 04/2009 
End 04/2012
 
Description CRUK funding (Arkadia in cancer)
Amount £237,489 (GBP)
Organisation Cancer Research UK (CRUK) 
Sector Charity/Non Profit
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 03/2008 
End 03/2011
 
Description Mehdi Motallebipour fellowship
Amount 1,000,000 kr (SEK)
Organisation Swedish Research Council 
Sector Public
Country Switzerland, Swiss Confederation
Start 09/2009 
End 09/2011
 
Title Animal model for Epilepsy 
Description Epilepsy mouse model generated by a knockout of the Sox1 gene 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Year Produced 2006 
Provided To Others? Yes  
Impact Publications and collaborations Malas et al 2003 PMID: 12770556 Ekonomou et al 2005 PMID: 15882093 Donner et al 2007 PMID: 17140559 Donner et al 2007 PMID: 17306631 Kan et al 2007 PMID: 17719572 
URL http://europepmc.org/abstract/MED/22366797
 
Title TGFbeta induced target gene profiling in ES cells 
Description Microarray data base with the profiles of thousands of gene in ES cells responding over time to TGFbeta signaling. 
Type Of Material Biological samples 
Year Produced 2009 
Provided To Others? Yes  
Impact Publication: Guzman-Ayala et al 2009 PMCID: PMC2627943 
URL http://www.ebi.ac.uk/microarray-as/ae/browse.html?keywords=E-TABM-574
 
Title miRNAs directly regulated by TGFbeta-Smad2/3 in ES cells 
Description micro RNA sequencing database 
Type Of Material Biological samples 
Provided To Others? No  
Impact Determining the targets of the multiple miRNAs generated from the TGF-ß-activated pri-miR-341~3072 gene by experimental validation of our predictions will harness our understanding of what are the key mediators of TGF-ß pathway function in early development. As TGF-ß signaling plays a major role throughout development and in adult tissue homeostasis, it is involved in congenital and adult diseases such as cancer. Understanding the role of this pathway in miRNA regulation will shed light on the mediators of its function and malfunction, and open new therapeutic approaches for cancer treatment. 
URL http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE39994
 
Title TGFbeta gene expression profile over time in mouse Embryonic Stem Cells 
Description gene expression profile over time under stimulation with TGFbeta ligand Activin in mouse Embryonic Stem Cells assayed with microarrays. This is published in the following URL: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004268 Graded Smad2/3 Activation Is Converted Directly into Levels of Target Gene Expression in Embryonic Stem Cells. PLoS ONE 4(2): 10.1371/annotation/8f64f0c8-6767-4701-8ded-7f937d953cb6. doi:10.1371/annotation/8f64f0c8-6767-4701-8ded-7f937d953cb6 The data can be found at: http://www.ebi.ac.uk/microarray-as/ae/browse.html?keywords=E-TABM-574 
Type Of Material Database/Collection of data 
Year Produced 2009 
Provided To Others? Yes  
Impact 8,328 views so far 24 citations so far for updated results see URL http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004268 
URL http://www.ebi.ac.uk/microarray-as/ae/browse.html?keywords=E-TABM-574
 
Description Analysis of the Sox1 epilepsy mouse model 
Organisation Northwestern University Chicago
Country United States of America 
Sector Academic/University 
PI Contribution The collaborators conducted the study and we provided the knockout mice and research insights. The study is published Kan et al 2007
Collaborator Contribution The collaborators conducted the study and we provided the knockout mice and research insights. The study is published Kan et al 2007
Impact The study is published Kan et al 2007 PMID: 17719572
 
Description Arakdia molecular mechanism 
Organisation Cancer Research UK (CRUK)
Department London Research Institute (LRI)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Charity/Non Profit 
PI Contribution experimental data and materials
Collaborator Contribution experimental data and materials
Impact Publication: Levy L, Howell M, Das D, Harkin S, Episkopou V, Hill CSet al., 2007, Arkadia activates Smad3/Smad4-Dependent transcription by triggering signal-induced SnoN degradation, MOLECULAR AND CELLULAR BIOLOGY, Vol: 27, Pages: 6068-6083, ISSN: 0270-7306
Start Year 2006
 
Description Arkadia melecular Mechanism 3 
Organisation University of Crete (UOC)
Department School of Medicine
Country Greece, Hellenic Republic 
Sector Academic/University 
PI Contribution We provide materials and insights. The preliminary data was used to write project grants.
Collaborator Contribution the collaborators provided materials, research insights and conducted experiments for us. The preliminary data was used to write project grant applications.
Impact The preliminary data was used to write project grants which was not funded and therefore the collaboration was terminated
Start Year 2007
 
Description Arkadia molecular mechanism 2 
Organisation University of Tokyo
Country Japan 
Sector Academic/University 
PI Contribution experimental data and materials
Collaborator Contribution experimental data and materials
Impact Publication: Nagano Y, Mavrakis KJ, Lee KL, Fujii T, Koinuma D, Sase H, Yuki K, Isogaya K, Saitoh M, Imamura T, Episkopou V, Miyazono K, Miyazawa Ket al., 2007, Arkadia induces degradation of SnoN and c-Ski to enhance transforming growth factor-beta signaling, JOURNAL OF BIOLOGICAL CHEMISTRY, Vol: 282, Pages: 20492-20501, ISSN: 0021-9258
Start Year 2006
 
Description Colorectal Cancer project 
Organisation University of Patras
Department Oncology Department Patras
Country Greece, Hellenic Republic 
Sector Academic/University 
PI Contribution provided experimental insights and materials. Based on the preliminary study we got a CRUK 3 year project grant to continue this collaboration. Therefore, this collaboration brought to our lab £237,489.
Collaborator Contribution Provided cancer patients and conducted a study based on our experimental insights. This study was published: Bravou et al 2009. The data provided the basis for winning a CRUK project grant (2008-2011) £237.489
Impact two publications: Bravou V, Antonacopoulou A, Papadaki H, Floratou K, Stavropoulos M, Episkopou V, Petropoulou C, Kalofonos Het al., 2009, TGF-beta repressors SnoN and Ski are implicated in human colorectal carcinogenesis, CELLULAR ONCOLOGY, Vol: 31, Pages: 41-51, ISSN: 1570-5870 Sharma V, Antonacopoulou AG, Tanaka S, Panoutsopoulos AA, Bravou V, Kalofonos HP, Episkopou Vet al., 2011, Enhancement of TGF-beta Signaling Responses by the E3 Ubiquitin Ligase Arkadia Provides Tumor Suppression in Colorectal Cancer, CANCER RESEARCH, Vol: 71, Pages: 6438-6449, ISSN: 0008-5472
Start Year 2006
 
Description Embryonic Stem Cell Differentiation Studies 
Organisation Academy of Athens
Department Biomedical Research Foundation Academy of Athens
Country Greece, Hellenic Republic 
Sector Academic/University 
PI Contribution The collaborators conducted the study and we facilitated this by providing materials and ideas. The study was published: Serafimidis et al 2008
Collaborator Contribution The collaborators conducted the study and we facilitated this by providing materials and ideas and training. The study was published in two papers:
Impact one publication: Serafimidis et al 2008 PMID: 17932425 Bami M, Episkopou V, Gavalas A, Gouti Met al., 2011, Directed Neural Differentiation of Mouse Embryonic Stem Cells Is a Sensitive System for the Identification of Novel Hox Gene Effectors, PLOS ONE, Vol: 6, ISSN: 1932-6203 Serafimidis I, Rakatzi I, Episkopou V, Gouti M, Gavalas Aet al., 2008, Novel effectors of directed and Ngn3-mediated differentiation of mouse embryonic stem cells into endocrine pancreas progenitors, STEM CELLS, Vol: 26, Pages: 3-16, ISSN: 1066-5099
 
Description NMR Structural studies on Arkadia 
Organisation University of Patras
Department Pharmacology Department Patras
Country Greece, Hellenic Republic 
Sector Academic/University 
PI Contribution we provided materials and insights
Collaborator Contribution conducted the study based on our materials and ideas. The preliminary results are published: Kandias et al 2009. They also used the data for an EU grant application (pending)
Impact one publication: Kandias NG, Chasapis CT, Bentrop D, Episkopou V, Spyroulias GAet al., 2009, High yield expression and NMR characterization of Arkadia E3 ubiquitin ligase RING-H2 finger domain, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, Vol: 378, Pages: 498-502, ISSN: 0006-291X
Start Year 2007
 
Description Sox1 and Sox2 knockout mouse analysis 
Organisation Harvard University
Department Harvard Medical School
Country United States of America 
Sector Academic/University 
PI Contribution provided the knockout mice and experimental insights.
Collaborator Contribution 2 studies were conducted by our collaborators on our knockout mouse lines using our research insights. The data were published in 2 papers:
Impact 2 publications: Donner AL, Episkopou V, Maas RL, 2007, Sox2 and Pou2f1 interact to control lens and olfactory placode development, DEVELOPMENTAL BIOLOGY, Vol: 303, Pages: 784-799, ISSN: 0012-1606 Donner AL, Ko F, Episkopou V, Maas RLet al., 2007, Pax6 is misexpressed in Sox1 null lens fiber cells, GENE EXPRESSION PATTERNS, Vol: 7, Pages: 606-613, ISSN: 1567-133X
 
Description Sox1CreERT2 in fate mapping of precursors in mice 
Organisation Medical Research Council (MRC)
Department MRC National Institute for Medical Research (NIMR)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution We made the knockout construct and ES cells to generate the mouse model.
Collaborator Contribution The collaborators used our Knockout mouse model.
Impact A high impact publication: Kicheva A, Bollenbach T, Ribeiro A, Valle HP, Lovell-Badge R, Episkopou V, Briscoe Jet al., 2014, Coordination of progenitor specification and growth in mouse and chick spinal cord, SCIENCE, Vol: 345, Pages: 1577-+, ISSN: 0036-8075
Start Year 2006
 
Description TGFbeta induced miRNA 
Organisation University of Oxford
Department Wellcome Trust Centre for Human Genetics
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Academic/University 
PI Contribution We contribute the experimental materials and insights
Collaborator Contribution The collaborators perform deep sequencing service and do the bioinformatic analysis.
Impact publication Redshaw N, Camps C, Sharma V, Motallebipour M, Guzman-Ayala M, Oikonomopoulos S, Thymiakou E, Ragoussis J, Episkopou Vet al., 2013, TGF-beta/Smad2/3 Signaling Directly Regulates Several miRNAs in Mouse ES Cells and Early Embryos, PLOS ONE, Vol: 8, ISSN: 1932-6203
Start Year 2007
 
Description TGFbeta signaling regulators TRAP1 
Organisation Heinrich Heine University Düsseldorf
Department Institute for Medical Microbiology and Hospital Hygiene
Country Germany, Federal Republic of 
Sector Academic/University 
PI Contribution performed mouse embryological expression analysis, and trained members of the collaborating team.
Collaborator Contribution funded a collaborative project
Impact a publication in Immunology The TGF-ß signaling modulators TRAP1/TGFBRAP1 and VPS39/Vam6/TLP are essential for early embryonic development. Messler S, Kropp S, Episkopou V, Felici A, Würthner J, Lemke R, Jerabek-Willemsen M, Willecke R, Scheu S, Pfeffer K, Wurthner JU.
Start Year 2007
 
Description spinal cord development 
Organisation Medical Research Council (MRC)
Department MRC National Institute for Medical Research (NIMR)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution Designing of the experiments generation of genetically modified mouse strain Sox1-Cre ERT-2 and writing and authoring a publication
Collaborator Contribution Designing experiments performing experiments and generating data analysis of data and writing and authoring a publication
Impact a high profile and impact publication Coordination of progenitor specification and growth in mouse and chick spinal cord. Kicheva A, Bollenbach T, Ribeiro A, Valle HP, Lovell-Badge R, Episkopou V, Briscoe J. Science. 2014 Sep 26;345(6204):1254927. doi: 10.1126/science.1254927. PMID: 25258086 [PubMed - indexed for MEDLINE]
Start Year 2006
 
Description Open Day on Stem cells, Athens Greece 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact I gave a talk to a general audience and participated in the discussion about ethics and stem cells I deposited the presentation to the society's web site to be used in teaching and information to wide audience

teaching and information to the public
Year(s) Of Engagement Activity 2007