1
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Consequences of telomere dysfunction in fibroblasts, club and basal cells for lung fibrosis development. Nat Commun 2022; 13:5656. [PMID: 36202783 PMCID: PMC9537293 DOI: 10.1038/s41467-022-32771-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/16/2022] [Indexed: 11/08/2022] Open
Abstract
TRF1 is an essential component of the telomeric protective complex or shelterin. We previously showed that dysfunctional telomeres in alveolar type II (ATII) cells lead to interstitial lung fibrosis. Here, we study the lung pathologies upon telomere dysfunction in fibroblasts, club and basal cells. TRF1 deficiency in lung fibroblasts, club and basal cells induced telomeric damage, proliferative defects, cell cycle arrest and apoptosis. While Trf1 deletion in fibroblasts does not spontaneously lead to lung pathologies, upon bleomycin challenge exacerbates lung fibrosis. Unlike in females, Trf1 deletion in club and basal cells from male mice resulted in lung inflammation and airway remodeling. Here, we show that depletion of TRF1 in fibroblasts, Club and basal cells does not lead to interstitial lung fibrosis, underscoring ATII cells as the relevant cell type for the origin of interstitial fibrosis. Our findings contribute to a better understanding of proper telomere protection in lung tissue homeostasis.
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2
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Global hyperactivation of enhancers stabilizes human and mouse naive pluripotency through inhibition of CDK8/19 Mediator kinases. Nat Cell Biol 2020; 22:1223-1238. [PMID: 32989249 DOI: 10.1038/s41556-020-0573-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
Pluripotent stem cells (PSCs) transition between cell states in vitro, reflecting developmental changes in the early embryo. PSCs can be stabilized in the naive state by blocking extracellular differentiation stimuli, particularly FGF-MEK signalling. Here, we report that multiple features of the naive state in human and mouse PSCs can be recapitulated without affecting FGF-MEK signalling or global DNA methylation. Mechanistically, chemical inhibition of CDK8 and CDK19 (hereafter CDK8/19) kinases removes their ability to repress the Mediator complex at enhancers. CDK8/19 inhibition therefore increases Mediator-driven recruitment of RNA polymerase II (RNA Pol II) to promoters and enhancers. This efficiently stabilizes the naive transcriptional program and confers resistance to enhancer perturbation by BRD4 inhibition. Moreover, naive pluripotency during embryonic development coincides with a reduction in CDK8/19. We conclude that global hyperactivation of enhancers drives naive pluripotency, and this can be achieved in vitro by inhibiting CDK8/19 kinase activity. These principles may apply to other contexts of cellular plasticity.
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3
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Engelmann C, Riemann M, Carlstedt S, Grimlowski R, Andreas N, Koliesnik I, Meier E, Austerfield P, Haenold R. Identification of undescribed Relb expression domains in the murine brain by new Relb:cre-katushka reporter mice. Dev Dyn 2020; 249:983-997. [PMID: 32145043 DOI: 10.1002/dvdy.170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/07/2020] [Accepted: 02/27/2020] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Noncanonical NF-κB signaling through activation of the transcription factor RelB acts as key regulator of cell lineage determination and differentiation in various tissues including the immune system. To elucidate temporospatial aspects of Relb expression, we generated a BAC transgenic knock-in mouse expressing the fluorescent protein Katushka and the enzyme Cre recombinase under control of the murine Relb promoter (RelbCre-Kat mice). RESULTS Co-expression of Katushka and Relb in fibroblast cultures and tissues of transgenic mice revealed highly specific reporter functions of the transgene. Crossing RelbCre-Kat mice with ROSA26R reporter mice that allow for Cre-mediated consecutive β-galactosidase or YFP synthesis identified various Relb expression domains in perinatal and mature mice. Besides thymus and spleen, highly specific expression patterns were found in different neuronal domains, as well as in other nonimmune organs including skin, skeletal structures and kidney. De novo Relb expression in the mature brain was confirmed in conditional knockout mice with neuro-ectodermal Relb deletion. CONCLUSION Our results demonstrate the usability of RelbCre-Kat reporter mice for the detection of de novo and temporarily restricted Relb expression including cell and lineage tracing of Relb expressing cells. Relb expression during mouse embryogenesis and at adulthood suggests, beyond immunity, important functions of this transcription factor in neurodevelopment and CNS function.
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Affiliation(s)
| | - Marc Riemann
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Swen Carlstedt
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,Jena University Hospital, Institute of Biochemistry II, Center for Sepsis Control and Care, Jena, Germany
| | - Randy Grimlowski
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Nico Andreas
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,Jena University Hospital, Institute of Immunology, Jena, Germany
| | - Ievgen Koliesnik
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,School of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, USA
| | - Elke Meier
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | | | - Ronny Haenold
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
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4
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Chaves-Pérez A, Yilmaz M, Perna C, de la Rosa S, Djouder N. URI is required to maintain intestinal architecture during ionizing radiation. Science 2019; 364:364/6443/eaaq1165. [PMID: 31147493 DOI: 10.1126/science.aaq1165] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 08/13/2018] [Accepted: 04/10/2019] [Indexed: 12/16/2022]
Abstract
Ionizing radiation (IR) can cause gastrointestinal syndrome (GIS), a lethal disorder, by means of unknown mechanisms. We show that high-dose irradiation increases unconventional prefoldin RPB5 interactor (URI) levels in mouse intestinal crypt, but organ regeneration correlates with URI reductions. URI overexpression in intestine protects mice from radiation-induced GIS, whereas halving URI expression sensitizes mice to IR. URI specifically inhibits β-catenin in stem cell-like label-retaining (LR) cells, which are essential for organ regeneration after IR. URI reduction activates β-catenin-induced c-MYC expression, causing proliferation of and DNA damage to LR cells, rendering them radiosensitive. Therefore, URI labels LR cells which promote tissue regeneration in response to high-dose irradiation, and c-MYC inhibitors could be countermeasures for humans at risk of developing GIS.
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Affiliation(s)
- Almudena Chaves-Pérez
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Mahmut Yilmaz
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Cristian Perna
- Department of Pathology, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid 28034, Spain
| | - Sergio de la Rosa
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Nabil Djouder
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain.
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5
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Costa-Machado LF, Martín-Hernández R, Sanchez-Luengo MÁ, Hess K, Vales-Villamarin C, Barradas M, Lynch C, de la Nava D, Diaz-Ruiz A, de Cabo R, Cañamero M, Martinez L, Sanchez-Carbayo M, Herranz D, Serrano M, Fernandez-Marcos PJ. Sirt1 protects from K-Ras-driven lung carcinogenesis. EMBO Rep 2018; 19:e43879. [PMID: 30021836 PMCID: PMC6123659 DOI: 10.15252/embr.201643879] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 06/18/2018] [Accepted: 06/22/2018] [Indexed: 12/21/2022] Open
Abstract
The NAD+-dependent deacetylase SIRT1 can be oncogenic or tumor suppressive depending on the tissue. Little is known about the role of SIRT1 in non-small cell lung carcinoma (NSCLC), one of the deadliest cancers, that is frequently associated with mutated K-RAS Therefore, we investigated the effect of SIRT1 on K-RAS-driven lung carcinogenesis. We report that SIRT1 protein levels are downregulated by oncogenic K-RAS in a MEK and PI3K-dependent manner in mouse embryo fibroblasts (MEFs), and in human lung adenocarcinoma cell lines. Furthermore, Sirt1 overexpression in mice delays the appearance of K-RasG12V-driven lung adenocarcinomas, reducing the number and size of carcinomas at the time of death and extending survival. Consistently, lower levels of SIRT1 are associated with worse prognosis in human NSCLCs. Mechanistically, analysis of mouse Sirt1-Tg pneumocytes, isolated shortly after K-RasG12V activation, reveals that Sirt1 overexpression alters pathways involved in tumor development: proliferation, apoptosis, or extracellular matrix organization. Our work demonstrates a tumor suppressive role of SIRT1 in the development of K-RAS-driven lung adenocarcinomas in mice and humans, suggesting that the SIRT1-K-RAS axis could be a therapeutic target for NSCLCs.
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Affiliation(s)
- Luis Filipe Costa-Machado
- Bioactive Products and Metabolic Syndrome Group - BIOPROMET, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Roberto Martín-Hernández
- GENYAL Nutrigenomic Platform, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | | | - Katharina Hess
- Tumor Suppression Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Claudia Vales-Villamarin
- Bioactive Products and Metabolic Syndrome Group - BIOPROMET, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Marta Barradas
- Bioactive Products and Metabolic Syndrome Group - BIOPROMET, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Cian Lynch
- Tumor Suppression Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Daniel de la Nava
- Bioactive Products and Metabolic Syndrome Group - BIOPROMET, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Alberto Diaz-Ruiz
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
- Nutritional Interventions Group, Precision Nutrition and Aging, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
- Nutritional Interventions Group, Precision Nutrition and Aging, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Marta Cañamero
- Histopathology Unit, Spanish National Cancer Research Center (CNIO), Madrid, Spain
- Pathology and Tissue Analysis, Pharma Research and Early Development Roche Innovation Centre, Munich, Germany
| | - Lola Martinez
- Flow Cytometry Unit, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Marta Sanchez-Carbayo
- Translational Oncology Lab, Lucio Lascaray Research Center, University of the Basque Country, Vitoria-Gasteiz, Spain
| | - Daniel Herranz
- Tumor Suppression Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain
- Rutgers Cancer Institute of New Jersey and Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Manuel Serrano
- Tumor Suppression Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Pablo J Fernandez-Marcos
- Bioactive Products and Metabolic Syndrome Group - BIOPROMET, Madrid Institute for Advanced Studies - IMDEA Food, CEI UAM+CSIC, Madrid, Spain
- Tumor Suppression Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain
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6
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Sánchez-Luengo MÁ, Rovira M, Serrano M, Fernandez-Marcos PJ, Martinez L. Analysis of the advantages of cis reporters in optimized FACS-Gal. Cytometry A 2017; 91:721-729. [PMID: 28375558 DOI: 10.1002/cyto.a.23086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/29/2016] [Accepted: 02/23/2017] [Indexed: 11/09/2022]
Abstract
Flow cytometry is a powerful multiparametric technology, widely used for the identification, quantification, and isolation of defined populations of cells based on the expression of target proteins. It also allows for the use of surrogate reporters, either enzymatic or fluorescent, to indirectly monitor the expression of these target proteins. In this work, we optimised the dissociation protocol for the detection of the enzymatic reporter LacZ using the FACS-Gal detection system with the fluorogenic substrate FDG to compare cis- versus trans-positioned reporters efficiency. Particularly, for the FACS-Gal optimization, we studied lung and haematopoietic tissues, focusing on cell recovery, viability, FDG loading conditions and distribution of cellular populations. Reporter genes such as LacZ can be placed together with the gene of interest in the same polycistronic mRNA (in cis), or in independent alleles (in trans), which can strongly affect the correlation with the reporter readout. To address this issue, we generated a mouse model containing both types of reporters for the same gene, and compared them. Our results clearly indicate that trans-positioned reporters can be misleading, and that using a reporter gene in cis rather than trans is a much more specific method to sort for cells undergoing Cre-mediated recombination. © 2017 International Society for Advancement of Cytometry.
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Affiliation(s)
- Miguel Ángel Sánchez-Luengo
- Flow Cytometry Unit, Biotechnology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | - Miguel Rovira
- Tumor Suppression Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | - Manuel Serrano
- Tumor Suppression Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
| | - Pablo Jose Fernandez-Marcos
- Tumor Suppression Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain.,Bioactive Products and Metabolic Syndrome (BIOPROMET), Madrid Institute for Advanced Studies (IMDEA) in Food, CEI UAM + CSIC, Madrid, E28049, Spain
| | - Lola Martinez
- Flow Cytometry Unit, Biotechnology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, E28029, Spain
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7
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Aiello NM, Stanger BZ. Echoes of the embryo: using the developmental biology toolkit to study cancer. Dis Model Mech 2016; 9:105-14. [PMID: 26839398 PMCID: PMC4770149 DOI: 10.1242/dmm.023184] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hallmark of embryonic development is regulation - the tendency for cells to find their way into organized and 'well behaved' structures - whereas cancer is characterized by dysregulation and disorder. At face value, cancer biology and developmental biology would thus seem to have little to do with each other. But if one looks beneath the surface, embryos and cancers share a number of cellular and molecular features. Embryos arise from a single cell and undergo rapid growth involving cell migration and cell-cell interactions: features that are also seen in the context of cancer. Consequently, many of the experimental tools that have been used to study embryogenesis for over a century are well-suited to studying cancer. This article will review the similarities between embryogenesis and cancer progression and discuss how some of the concepts and techniques used to understand embryos are now being adapted to provide insight into tumorigenesis, from the origins of cancer cells to metastasis.
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Affiliation(s)
- Nicole M Aiello
- Departments of Medicine and Cell and Developmental Biology, Abramson Family Cancer Research Institute, and Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Ben Z Stanger
- Departments of Medicine and Cell and Developmental Biology, Abramson Family Cancer Research Institute, and Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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8
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Arranz A, Ripoll J. Advances in optical imaging for pharmacological studies. Front Pharmacol 2015; 6:189. [PMID: 26441646 PMCID: PMC4566037 DOI: 10.3389/fphar.2015.00189] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/21/2015] [Indexed: 11/13/2022] Open
Abstract
Imaging approaches are an essential tool for following up over time representative parameters of in vivo models, providing useful information in pharmacological studies. Main advantages of optical imaging approaches compared to other imaging methods are their safety, straight-forward use and cost-effectiveness. A main drawback, however, is having to deal with the presence of high scattering and high absorption in living tissues. Depending on how these issues are addressed, three different modalities can be differentiated: planar imaging (including fluorescence and bioluminescence in vivo imaging), optical tomography, and optoacoustic approaches. In this review we describe the latest advances in optical in vivo imaging with pharmacological applications, with special focus on the development of new optical imaging probes in order to overcome the strong absorption introduced by different tissue components, especially hemoglobin, and the development of multimodal imaging systems in order to overcome the resolution limitations imposed by scattering.
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Affiliation(s)
- Alicia Arranz
- Department of Cell Biology and Immunology, Center for Molecular Biology "Severo Ochoa", Spanish National Research Council , Madrid, Spain
| | - Jorge Ripoll
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III of Madrid , Madrid, Spain ; Experimental Medicine and Surgery Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón , Madrid, Spain
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9
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Povedano JM, Martinez P, Flores JM, Mulero F, Blasco MA. Mice with Pulmonary Fibrosis Driven by Telomere Dysfunction. Cell Rep 2015; 12:286-99. [PMID: 26146081 DOI: 10.1016/j.celrep.2015.06.028] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/01/2015] [Accepted: 06/05/2015] [Indexed: 12/23/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a degenerative disease of the lungs with an average survival post-diagnosis of 2-3 years. New therapeutic targets and treatments are necessary. Mutations in components of the telomere-maintenance enzyme telomerase or in proteins important for telomere protection are found in both familial and sporadic IPF cases. However, the lack of mouse models that faithfully recapitulate the human disease has hampered new advances. Here, we generate two independent mouse models that develop IPF owing to either critically short telomeres (telomerase-deficient mice) or severe telomere dysfunction in the absence of telomere shortening (mice with Trf1 deletion in type II alveolar cells). We show that both mouse models develop pulmonary fibrosis through induction of telomere damage, thus providing proof of principle of the causal role of DNA damage stemming from dysfunctional telomeres in IPF development and identifying telomeres as promising targets for new treatments.
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Affiliation(s)
- Juan M Povedano
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid 28029, Spain
| | - Paula Martinez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid 28029, Spain
| | - Juana M Flores
- Animal Surgery and Medicine Department, Faculty of Veterinary Science, Complutense University of Madrid, Madrid 28029, Spain
| | - Francisca Mulero
- Molecular Imaging Unit, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, Madrid 28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid 28029, Spain.
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10
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Trakala M, Rodríguez-Acebes S, Maroto M, Symonds CE, Santamaría D, Ortega S, Barbacid M, Méndez J, Malumbres M. Functional reprogramming of polyploidization in megakaryocytes. Dev Cell 2015; 32:155-67. [PMID: 25625205 DOI: 10.1016/j.devcel.2014.12.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 10/31/2014] [Accepted: 12/17/2014] [Indexed: 12/30/2022]
Abstract
Polyploidization is a natural process that frequently accompanies differentiation; its deregulation is linked to genomic instability and cancer. Despite its relevance, why cells select different polyploidization mechanisms is unknown. Here we report a systematic genetic analysis of endomitosis, a process in which megakaryocytes become polyploid by entering mitosis but aborting anaphase. Whereas ablation of the APC/C cofactor Cdc20 results in mitotic arrest and severe thrombocytopenia, lack of the kinases Aurora-B, Cdk1, or Cdk2 does not affect megakaryocyte polyploidization or platelet levels. Ablation of Cdk1 forces a switch to endocycles without mitosis, whereas polyploidization in the absence of Cdk1 and Cdk2 occurs in the presence of aberrant re-replication events. Importantly, ablation of these kinases rescues the defects in Cdc20 null megakaryocytes. These findings suggest that endomitosis can be functionally replaced by alternative polyploidization mechanisms in vivo and provide the cellular basis for therapeutic approaches aimed to discriminate mitotic and polyploid cells.
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Affiliation(s)
- Marianna Trakala
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | | | - María Maroto
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | | | | | | | | | - Juan Méndez
- DNA Replication Group, CNIO, 28029 Madrid, Spain
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
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11
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López-Iglesias P, Alcaina Y, Tapia N, Sabour D, Arauzo-Bravo MJ, Sainz de la Maza D, Berra E, O'Mara AN, Nistal M, Ortega S, Donovan PJ, Schöler HR, De Miguel MP. Hypoxia induces pluripotency in primordial germ cells by HIF1α stabilization and Oct4 deregulation. Antioxid Redox Signal 2015; 22:205-23. [PMID: 25226357 DOI: 10.1089/ars.2014.5871] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS To study the mechanisms of pluripotency induction, we compared gene expression in pluripotent embryonic germ cells (EGCs) and unipotent primordial germ cells (PGCs). RESULTS We found 11 genes ≥1.5-fold overexpressed in EGCs. None of the genes identified was the Yamanaka genes but instead related to glycolytic metabolism. The prospect of pluripotency induction by cell metabolism manipulation was investigated by hypoxic culturing. Hypoxia induced a glycolytic program in PGCs in detriment of mitochondrial oxidative phosphorylation. We demonstrate that hypoxia alone induces reprogramming in PGCs, giving rise to hypoxia-induced EGC-like cells (hiEGLs), which differentiate into cells of the three germ layers in vitro and contribute to the internal cell mass of the blastocyst in vivo, demonstrating pluripotency. The mechanism of hypoxia induction involves HIF1α stabilization and Oct4 deregulation. However, hiEGL cannot be passaged long term. Self-renewal capacity is not achieved by hypoxia likely due to the lack of upregulation of c-Myc and Klf4. Gene expression analysis of hypoxia signaling suggests that hiEGLs have not reached the stabilization phase of cell reprogramming. INNOVATION AND CONCLUSION Our data suggest that the two main properties of stemness, pluripotency and self-renewal, are differentially regulated in PGC reprogramming induced by hypoxia.
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Affiliation(s)
- Pilar López-Iglesias
- 1 Cell Engineering Laboratory, IdiPaz, La Paz Hospital Research Institute , Madrid Spain
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12
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Castellana D, Paus R, Perez-Moreno M. Macrophages contribute to the cyclic activation of adult hair follicle stem cells. PLoS Biol 2014; 12:e1002002. [PMID: 25536657 PMCID: PMC4275176 DOI: 10.1371/journal.pbio.1002002] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/10/2014] [Indexed: 12/17/2022] Open
Abstract
Castellana, Paus, and Perez-Moreno discover that skin resident macrophages signal to skin stem cells via Wnt ligands to activate the hair follicle life cycle. Skin epithelial stem cells operate within a complex signaling milieu that orchestrates their lifetime regenerative properties. The question of whether and how immune cells impact on these stem cells within their niche is not well understood. Here we show that skin-resident macrophages decrease in number because of apoptosis before the onset of epithelial hair follicle stem cell activation during the murine hair cycle. This process is linked to distinct gene expression, including Wnt transcription. Interestingly, by mimicking this event through the selective induction of macrophage apoptosis in early telogen, we identify a novel involvement of macrophages in stem cell activation in vivo. Importantly, the macrophage-specific pharmacological inhibition of Wnt production delays hair follicle growth. Thus, perifollicular macrophages contribute to the activation of skin epithelial stem cells as a novel, additional cue that regulates their regenerative activity. This finding may have translational implications for skin repair, inflammatory skin diseases and cancer. The cyclic life of hair follicles consists of recurring phases of growth, decay, and rest. Previous studies have identified signals that prompt a new phase of hair growth through the activation of resting hair follicle stem cells (HF-SCs). In addition to these signals, recent findings have shown that cues arising from the neighboring skin environment, in which hair follicles dwell, also participate in controlling hair follicle growth. Here we show that skin resident macrophages surround and signal to resting HF-SCs, regulating their entry into a new phase of hair follicle growth. This process involves the death and activation of a fraction of resident macrophages— resulting in Wnt ligand release —that in turn activate HF-SCs. These findings reveal additional mechanisms controlling endogenous stem cell pools that are likely to be relevant for modulating stem cell regenerative capabilities. The results provide new insights that may have implications for the development of technologies with potential applications in regeneration, aging, and cancer.
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Affiliation(s)
- Donatello Castellana
- Epithelial Cell Biology Group, BBVA Foundation-CNIO Cancer Cell Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ralf Paus
- Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Department of Dermatology, University of Münster, Münster, Germany
| | - Mirna Perez-Moreno
- Epithelial Cell Biology Group, BBVA Foundation-CNIO Cancer Cell Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- * E-mail:
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13
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Isern J, García-García A, Martín AM, Arranz L, Martín-Pérez D, Torroja C, Sánchez-Cabo F, Méndez-Ferrer S. The neural crest is a source of mesenchymal stem cells with specialized hematopoietic stem cell niche function. eLife 2014; 3:e03696. [PMID: 25255216 PMCID: PMC4381911 DOI: 10.7554/elife.03696] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/24/2014] [Indexed: 12/17/2022] Open
Abstract
Mesenchymal stem cells (MSCs) and osteolineage cells contribute to the hematopoietic stem cell (HSC) niche in the bone marrow of long bones. However, their developmental relationships remain unclear. In this study, we demonstrate that different MSC populations in the developing marrow of long bones have distinct functions. Proliferative mesoderm-derived nestin− MSCs participate in fetal skeletogenesis and lose MSC activity soon after birth. In contrast, quiescent neural crest-derived nestin+ cells preserve MSC activity, but do not generate fetal chondrocytes. Instead, they differentiate into HSC niche-forming MSCs, helping to establish the HSC niche by secreting Cxcl12. Perineural migration of these cells to the bone marrow requires the ErbB3 receptor. The neonatal Nestin-GFP+ Pdgfrα− cell population also contains Schwann cell precursors, but does not comprise mature Schwann cells. Thus, in the developing bone marrow HSC niche-forming MSCs share a common origin with sympathetic peripheral neurons and glial cells, and ontogenically distinct MSCs have non-overlapping functions in endochondrogenesis and HSC niche formation. DOI:http://dx.doi.org/10.7554/eLife.03696.001 During the earliest phases of development, the embryo is formed by groups of stem cells that can develop into all the different types of tissue in the body—from bones to brain tissue. Later in life, small stockpiles of adult stem cells are found in various tissues and provide a reservoir of new cells available for replacing old or damaged cells. The most important source of blood stem cells is the bone marrow, which produces and stores cells that are capable of developing into blood and immune system cells. These processes are assisted by different bone marrow cells called stromal cells, which create a specialized local environment or ‘niche’. But are the stromal stem cells that form the skeleton the same ones that form this niche during development? Or do the various types of stromal stem cells develop from distinct groups of cells in the embryo? Furthermore, it is unclear which cells guide blood stem cells towards the forming bones. Other types of cells, including some of the cells of the nervous system, can communicate with the stem cells in the adult marrow and influence their behavior. This led scientists to wonder whether the stem cells in the bone marrow niche and the cells that communicate with them developed from the same type of embryonic stem cell. Isern et al. tracked down the developmental origins of different types of bone marrow stromal stem cells by examining the bone marrow from the long bones (for example, the bones in the leg) of unborn and infant mice. It turns out that not all stromal stem cells in the developing bone marrow are alike. In fact, one pool of stromal stem cells forms the skeleton and loses stem cell activity in the process. In contrast, a different population of stromal stem cells develops from the same group of embryonic cells that gives rise to the cells of the nervous system. The stromal stem cells in this second group function as a niche to recruit and store the incoming blood stem cells and retain their stem cell activity throughout life. The findings of Isern et al. help to explain why the nervous system is able to communicate with stem cells in the adult marrow, and provide a model for understanding how stem cell niches in organs that contain nerve tissue are established. DOI:http://dx.doi.org/10.7554/eLife.03696.002
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Affiliation(s)
- Joan Isern
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Andrés García-García
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Ana M Martín
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Lorena Arranz
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Daniel Martín-Pérez
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Carlos Torroja
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Fátima Sánchez-Cabo
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Simón Méndez-Ferrer
- Stem Cell Niche Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
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14
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Mezzanotte L, Blankevoort V, Löwik CWGM, Kaijzel EL. A novel luciferase fusion protein for highly sensitive optical imaging: from single-cell analysis to in vivo whole-body bioluminescence imaging. Anal Bioanal Chem 2014; 406:5727-34. [PMID: 24958343 PMCID: PMC4149884 DOI: 10.1007/s00216-014-7917-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/12/2014] [Accepted: 05/20/2014] [Indexed: 12/17/2022]
Abstract
Fluorescence and bioluminescence imaging have different advantages and disadvantages depending on the application. Bioluminescence imaging is now the most sensitive optical technique for tracking cells, promoter activity studies, or for longitudinal in vivo preclinical studies. Far-red and near-infrared fluorescence imaging have the advantage of being suitable for both ex vivo and in vivo analysis and have translational potential, thanks to the availability of very sensitive imaging instrumentation. Here, we report the development and validation of a new luciferase fusion reporter generated by the fusion of the firefly luciferase Luc2 to the far-red fluorescent protein TurboFP635 by a 14-amino acid linker peptide. Expression of the fusion protein, named TurboLuc, was analyzed in human embryonic kidney cells, (HEK)-293 cells, via Western blot analysis, fluorescence microscopy, and in vivo optical imaging. The created fusion protein maintained the characteristics of the original bioluminescent and fluorescent protein and showed no toxicity when expressed in living cells. To assess the sensitivity of the reporter for in vivo imaging, transfected cells were subcutaneously injected in animals. Detection limits of cells were 5 × 10(3) and 5 × 10(4) cells for bioluminescent and fluorescent imaging, respectively. In addition, hydrodynamics-based in vivo gene delivery using a minicircle vector expressing TurboLuc allowed for the analysis of luminescent signals over time in deep tissue. Bioluminescence could be monitored for over 30 days in the liver of animals. In conclusion, TurboLuc combines the advantages of both bioluminescence and fluorescence and allows for highly sensitive optical imaging ranging from single-cell analysis to in vivo whole-body bioluminescence imaging.
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Affiliation(s)
- Laura Mezzanotte
- Department of Radiology, Experimental Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Vicky Blankevoort
- Department of Radiology, Experimental Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Clemens W. G. M. Löwik
- Department of Radiology, Experimental Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Eric L. Kaijzel
- Department of Radiology, Experimental Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
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15
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Abad M, Mosteiro L, Pantoja C, Cañamero M, Rayon T, Ors I, Graña O, Megías D, Domínguez O, Martínez D, Manzanares M, Ortega S, Serrano M. Reprogramming in vivo produces teratomas and iPS cells with totipotency features. Nature 2013; 502:340-5. [PMID: 24025773 DOI: 10.1038/nature12586] [Citation(s) in RCA: 360] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/23/2013] [Indexed: 02/06/2023]
Abstract
Reprogramming of adult cells to generate induced pluripotent stem cells (iPS cells) has opened new therapeutic opportunities; however, little is known about the possibility of in vivo reprogramming within tissues. Here we show that transitory induction of the four factors Oct4, Sox2, Klf4 and c-Myc in mice results in teratomas emerging from multiple organs, implying that full reprogramming can occur in vivo. Analyses of the stomach, intestine, pancreas and kidney reveal groups of dedifferentiated cells that express the pluripotency marker NANOG, indicative of in situ reprogramming. By bone marrow transplantation, we demonstrate that haematopoietic cells can also be reprogrammed in vivo. Notably, reprogrammable mice present circulating iPS cells in the blood and, at the transcriptome level, these in vivo generated iPS cells are closer to embryonic stem cells (ES cells) than standard in vitro generated iPS cells. Moreover, in vivo iPS cells efficiently contribute to the trophectoderm lineage, suggesting that they achieve a more plastic or primitive state than ES cells. Finally, intraperitoneal injection of in vivo iPS cells generates embryo-like structures that express embryonic and extraembryonic markers. We conclude that reprogramming in vivo is feasible and confers totipotency features absent in standard iPS or ES cells. These discoveries could be relevant for future applications of reprogramming in regenerative medicine.
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Affiliation(s)
- María Abad
- Tumour Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
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16
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Snyder CS, Harrington AR, Kaushal S, Mose E, Lowy AM, Hoffman RM, Bouvet M. A dual-color genetically engineered mouse model for multispectral imaging of the pancreatic microenvironment. Pancreas 2013; 42:952-8. [PMID: 23648841 PMCID: PMC3713119 DOI: 10.1097/mpa.0b013e31828643df] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To develop a mouse model for multispectral fluorescence imaging of the pancreas and pancreatic microenvironment. METHODS Cre/loxP technology was used to develop this model. We crossed mT/mG indicator mice, engineered to constitutively express a conditional tdTomato transgene that converts to green fluorescent protein (GFP) expression after exposure to Cre recombinase, with Pdx1-Cre transgenic mice. To characterize this model for studies of pancreas biology, we performed bright light and fluorescence imaging of body cavities and intact organs and confocal microscopy of pancreata from offspring of Pdx1-Cre and mT/mG crosses. RESULTS Pdx1-Cre-mT/mG mice demonstrated bright GFP expression within the pancreas and duodenum and intense tdTomato expression in all other organs. Green fluorescent protein expression was mosaic in Pdx1-Cre-mT/mG pancreata, with most showing extensive conversion from tdTomato to GFP expression within the epithelial-derived elements of the pancreatic parenchyma. Because both GFP and tdTomato are membrane targeted, individual cell borders were clearly outlined in confocal images of mT/mG pancreata. CONCLUSIONS This mouse model enables multispectral fluorescence imaging of individual cells and cell processes at the microscopic level of the pancreatic microenvironment; it should prove valuable for a variety of fluorescence imaging studies, ranging from pancreatic development to pancreatic cancer biology.
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Affiliation(s)
- Cynthia S Snyder
- Department of Surgery, UCSD Moores Cancer Center, La Jolla, CA 92093-0987, USA
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17
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Rask L, Fregil M, Høgdall E, Mitchelmore C, Eriksen J. Development of a metastatic fluorescent Lewis Lung carcinoma mouse model: identification of mRNAs and microRNAs involved in tumor invasion. Gene 2013; 517:72-81. [PMID: 23296057 DOI: 10.1016/j.gene.2012.12.083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 11/19/2012] [Accepted: 12/19/2012] [Indexed: 12/21/2022]
Abstract
Cancer metastasis is the foremost cause of death in cancer patients. A series of observable pathological changes takes place during progression and metastasis of cancer, but the underlying genetic changes remain unclear. Therefore, new approaches are required, including insights from cancer mouse models. To examine the mechanisms involved in tumor metastasis, we first generated a stably transfected Lewis Lung carcinoma cell line expressing a far-red fluorescent protein, called Katushka. After in vivo growth in syngeneic mice, two fluorescent Lewis Lung cancer subpopulations were isolated from primary tumors and lung metastases. The metastasis-derived cells exhibited a significant improvement in in vitro invasive activity compared to the primary tumor-derived cells, using a quantitative invasion chamber assay. Moreover, expression levels of 84 tumor metastasis-related mRNAs, 88 cancer-related microRNAs as well as Dicer and Drosha were determined using RT-qPCR. Compared to the primary Lewis Lung carcinoma subculture, the metastasis-derived cells exhibited statistically significantly increased mRNA levels for several matrix metalloproteinases as well as hepatocyte growth factor (HGF) and spleen tyrosine kinase (SYK). A modest decrease in Drosha and Dicer mRNA levels was accompanied by significant downregulation of ten microRNAs, including miR-9 and miR-203, in the lung metastatic Lewis Lung carcinoma cell culture. Thus, a tool for cancer metastasis studies has been established and the model is well suited for the identification of novel microRNAs and mRNAs involved in malignant progression. Our results suggest that increases in metalloproteinase expression and impairment of microRNA processing are involved in the acquirement of metastatic ability.
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Affiliation(s)
- Lene Rask
- Department of Oncology 54O5, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark.
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18
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Shcherbakova DM, Subach OM, Verkhusha VV. Red fluorescent proteins: advanced imaging applications and future design. Angew Chem Int Ed Engl 2012; 51:10724-38. [PMID: 22851529 PMCID: PMC4433748 DOI: 10.1002/anie.201200408] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Indexed: 12/21/2022]
Abstract
In the past few years a large series of the advanced red-shifted fluorescent proteins (RFPs) has been developed. These enhanced RFPs provide new possibilities to study biological processes at the levels ranging from single molecules to whole organisms. Herein the relationship between the properties of the RFPs of different phenotypes and their applications to various imaging techniques are described. Existing and emerging imaging approaches are discussed for conventional RFPs, far-red FPs, RFPs with a large Stokes shift, fluorescent timers, irreversibly photoactivatable and reversibly photoswitchable RFPs. Advantages and limitations of specific RFPs for each technique are presented. Recent progress in understanding the chemical transformations of red chromophores allows the future RFP phenotypes and their respective novel imaging applications to be foreseen.
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Affiliation(s)
| | | | - Vladislav V. Verkhusha
- Department of Anatomy and Structural Biology and Gruss-Lipper, Biophotonics Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (USA)
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19
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Shcherbakova DM, Subach OM, Verkhusha VV. Rot fluoreszierende Proteine: spezielle Anwendungen in der Bildgebung und Perspektiven. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201200408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Affiliation(s)
- Fedor V. Subach
- Department of Anatomy and Structural Biology, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Vladislav V. Verkhusha
- Department of Anatomy and Structural Biology, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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21
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Hartwich H, Satheesh SV, Nothwang HG. A pink mouse reports the switch from red to green fluorescence upon Cre-mediated recombination. BMC Res Notes 2012; 5:296. [PMID: 22697046 PMCID: PMC3434021 DOI: 10.1186/1756-0500-5-296] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 06/08/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Targeted genetic modification in the mouse becomes increasingly important in biomedical and basic science. This goal is most often achieved by use of the Cre/loxP system and numerous Cre-driver mouse lines are currently generated. Their initial characterization requires reporter mouse lines to study the in vivo spatiotemporal activity of Cre. FINDINGS Here, we report a dual fluorescence reporter mouse line, which switches expression from the red fluorescent protein mCherry to eGFP after Cre-mediated recombination. Both fluorescent proteins are expressed from the ubiquitously active and strong CAGGS promoter. Among the founders, we noticed a pink mouse line, expressing high levels of the red fluorescent protein mCherry throughout the entire body. Presence of mCherry in the living animal as well as in almost all organs was clearly visible without optical equipment. Upon Cre-activity, mCherry expression was switched to eGFP, demonstrating functionality of this reporter mouse line. CONCLUSIONS The pink mouse presented here is an attractive novel reporter line for fluorescence-based monitoring of Cre-activity. The high expression of mCherry, which is visible to the naked eye, facilitates breeding and crossing, as no genotyping is required to identify mice carrying the reporter allele. The presence of two fluorescent proteins allows in vivo monitoring of recombined and non-recombined cells. Finally, the pink mouse is an eye-catching animal model to demonstrate the power of transgenic techniques in teaching courses.
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Affiliation(s)
- Heiner Hartwich
- Department of Neurogenetics, Institute of Biology and Environmental Sciences, Carl von Ossietzky University, Carl-von-Ossietzky-Straße 9-11, 26129, Oldenburg, Germany
| | - Somisetty V Satheesh
- Department of Neurogenetics, Institute of Biology and Environmental Sciences, Carl von Ossietzky University, Carl-von-Ossietzky-Straße 9-11, 26129, Oldenburg, Germany
| | - Hans Gerd Nothwang
- Department of Neurogenetics, Institute of Biology and Environmental Sciences, Carl von Ossietzky University, Carl-von-Ossietzky-Straße 9-11, 26129, Oldenburg, Germany
- Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129, Oldenburg, Germany
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22
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Xenopoulos P, Nowotschin S, Hadjantonakis AK. Live imaging fluorescent proteins in early mouse embryos. Methods Enzymol 2012; 506:361-89. [PMID: 22341233 DOI: 10.1016/b978-0-12-391856-7.00042-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mouse embryonic development comprises highly dynamic and coordinated events that drive key cell lineage specification and morphogenetic events. These processes involve cellular behaviors including proliferation, migration, apoptosis, and differentiation, each of which is regulated both spatially and temporally. Live imaging of developing embryos provides an essential tool to investigate these coordinated processes in three-dimensional space over time. For this purpose, the development and application of genetically encoded fluorescent protein (FP) reporters has accelerated over the past decade allowing for the high-resolution visualization of developmental progression. Ongoing efforts are aimed at generating improved reporters, where spectrally distinct as well as novel FPs whose optical properties can be photomodulated, are exploited for live imaging of mouse embryos. Moreover, subcellular tags in combination with using FPs allow for the visualization of multiple subcellular characteristics, such as cell position and cell morphology, in living embryos. Here, we review recent advances in the application of FPs for live imaging in the early mouse embryo, as well as some of the methods used for ex utero embryo development that facilitate on-stage time-lapse specimen visualization.
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23
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Snippert HJ, Schepers AG, Delconte G, Siersema PD, Clevers H. Slide preparation for single-cell-resolution imaging of fluorescent proteins in their three-dimensional near-native environment. Nat Protoc 2011; 6:1221-8. [PMID: 21799490 DOI: 10.1038/nprot.2011.365] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, many mouse models have been developed to mark and trace the fate of adult cell populations using fluorescent proteins. High-resolution visualization of such fluorescent markers in their physiological setting is thus an important aspect of adult stem cell research. Here we describe a protocol to produce sections (150-200 μm) of near-native tissue with optimal tissue and cellular morphology by avoiding artifacts inherent in standard freezing or embedding procedures. The activity of genetically expressed fluorescent proteins is maintained, thereby enabling high-resolution three-dimensional (3D) reconstructions of fluorescent structures in virtually all types of tissues. The procedure allows immunofluorescence labeling of proteins to depths up to 50 μm, as well as a chemical 'Click-iT' reaction to detect DNA-intercalating analogs such as ethynyl deoxyuridine (EdU). Generation of near-native sections ready for imaging analysis takes approximately 2-3 h. Postsectioning processes, such as antibody labeling or EdU detection, take up to 10 h.
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Affiliation(s)
- Hugo J Snippert
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
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24
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Gurskaia NG, Staroverov DB, Fradkov AF, Luk'ianov KA. [Coding region of far-red fluorescent protein katushka contains a strong donor splice site]. BIOORGANICHESKAIA KHIMIIA 2011; 37:425-8. [PMID: 21899059 DOI: 10.1134/s1068162011030071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Computer analysis predicted a strong donor splice site within the 3'-part of the far-red fluorescent protein Katushka coding region. To test the functional activity of this site a model vector has been constructed. This vector encoded Katushka and green fluorescent protein TagGFP2 with a gene fragment of tafazzin in between. Normal splicing of this pre-mRNA should result in a frameshift between Katushka and TagGFP2. Alternatively, after splicing at internal katushka donor splice site appearance of Katushka-TagGFP2 fusion protein was expected. Expression of this construct in a mammalian cell culture led to bright red and green fluorescence. Therefore, katushka-specific donor splice site is functional. Disruption of this splice site by several silent substitutions resulted in red-only fluorescent cells that corresponded to normal splicing. The mutant katushka can be used for visualization of pre-mRNA splicing at single cell level by fluorescence microscopy and flow cytometry.
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