21 results on '"Lopes, Susana M. Chuva de Sousa"'
Search Results
2. Human induced pluripotent stem cells display a similar mutation burden as embryonic pluripotent cells in vivo
- Author
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Hasaart, Karlijn A.L., primary, Manders, Freek, additional, Ubels, Joske, additional, Verheul, Mark, additional, van Roosmalen, Markus J., additional, Groenen, Niels M., additional, Oka, Rurika, additional, Kuijk, Ewart, additional, Lopes, Susana M. Chuva de Sousa, additional, and Boxtel, Ruben van, additional
- Published
- 2022
- Full Text
- View/download PDF
3. Human Microglia Acquire a More Mature, Homeostatic Phenotype During the Transition of the First and Second Trimester of Gestation
- Author
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Eskandar, Sharon, Borggrewe, Malte, Alsema, Astrid M., Brouwer, Nieske, Meijer, Michel, Lopes, Susana M. Chuva de Sousa, Nieveen, Maaike C., Kooistra, Susanne M., Scherjon, Sicco A., Prins, Jelmer R., Eggen, Bart J. L., Reproductive Origins of Adult Health and Disease (ROAHD), Molecular Neuroscience and Ageing Research (MOLAR), and Restoring Organ Function by Means of Regenerative Medicine (REGENERATE)
- Published
- 2020
4. Modeling human embryogenesis: embryo-like structures spark ethical and policy debate
- Author
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Daoud, Ana M. Pereira, Daoud, Ana M. Pereira, Popovic, Mina, Dondorp, Wybo J., Bustos, Marc Trani, Bredenoord, Annelien L., Lopes, Susana M. Chuva de Sousa, van den Brink, Susanne C., Roelen, Bernard A. J., de Wert, Guido M. W. R., Heindryckx, Bjorn, Daoud, Ana M. Pereira, Daoud, Ana M. Pereira, Popovic, Mina, Dondorp, Wybo J., Bustos, Marc Trani, Bredenoord, Annelien L., Lopes, Susana M. Chuva de Sousa, van den Brink, Susanne C., Roelen, Bernard A. J., de Wert, Guido M. W. R., and Heindryckx, Bjorn
- Abstract
BACKGROUND: Studying the human peri-implantation period remains hindered by the limited accessibility of the in vivo environment and scarcity of research material. As such, continuing efforts have been directed towards developing embryo-like structures (ELS) from pluripotent stem cells (PSCs) that recapitulate aspects of embryogenesis in vitro. While the creation of such models offers immense potential for studying fundamental processes in both pre- and early post-implantation development, it also proves ethically contentious due to wide-ranging views on the moral and legal reverence due to human embryos. Lack of clarity on how to qualify and regulate research with ELS thus presents a challenge in that it may either limit this new field of research without valid grounds or allow it to develop without policies that reflect justified ethical concerns.OBJECTIVE AND RATIONALE: The aim of this article is to provide a comprehensive overview of the existing scientific approaches to generate ELS from mouse and human PSCs, as well as discuss future strategies towards innovation in the context of human development. Concurrently, we aim to set the agenda for the ethical and policy issues surrounding research on human ELS.SEARCH METHODS: The PubMed database was used to search peer-reviewed articles and reviews using the following terms: 'stem cells', 'pluripotency', 'implantation', 'preimplantation', 'post-implantation', 'blastocyst, 'embryoid bodies', 'synthetic embryos', 'embryo models', 'self-assembly', 'human embryo-like structures', 'artificial embryos' in combination with other keywords related to the subject area. The PubMed and Web of Science databases were also used to systematically search publications on the ethics of ELS and human embryo research by using the aforementioned keywords in combination with 'ethics', 'law', 'regulation' and equivalent terms. All relevant publications until December 2019 were critically evaluated and discussed.OUTC
- Published
- 2020
5. BMP signaling mediated by ALK2 in the visceral endoderm is necessary for the generation of primordial germ cells in the mouse embryo
- Author
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Lopes, Susana M. Chuva de Sousa, Roelen, Bernard A. J., Monteiro, Rui M., Emmens, Roul, Lin, Herbert Y., En Li, Lawson, Kirstie A., and Mummery, Christine L.
- Subjects
Germ cells -- Research ,Ectoderm -- Diseases ,Bone morphogenetic proteins -- Research ,Biological sciences - Abstract
The omission of different bone morphogenetic proteins (BMPs) along with their downstream Smads in mice distinctly indicates that BMP signaling is important for the development of primordial germ cells. However, it is displayed that the BMP4 generated in the extraembryonic ectoderm indicates from ALK2, the first form of BMP receptor, in the visceral endoderm (VE) to introduce the development of PGCs from epiblast.
- Published
- 2004
6. Long-Term Expansion of Functional Mouse and Human Hepatocytes as 3D Organoids
- Author
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Hu, Huili, Hu, Huili, Gehart, Helmuth, Artegiani, Benedetta, Lopez-Iglesias, Carmen, Dekkers, Florijn, Basak, Onur, van Es, Johan, Lopes, Susana M. Chuva de Sousa, Begthel, Harry, Korving, Jeroen, van den Born, Maaike, Zou, Chenhui, Quirk, Corrine, Chiriboga, Luis, Rice, Charles M., Ma, Stephanie, Rios, Anne, Peters, Peter J., de Jong, Ype P., Clevers, Hans, Hu, Huili, Hu, Huili, Gehart, Helmuth, Artegiani, Benedetta, Lopez-Iglesias, Carmen, Dekkers, Florijn, Basak, Onur, van Es, Johan, Lopes, Susana M. Chuva de Sousa, Begthel, Harry, Korving, Jeroen, van den Born, Maaike, Zou, Chenhui, Quirk, Corrine, Chiriboga, Luis, Rice, Charles M., Ma, Stephanie, Rios, Anne, Peters, Peter J., de Jong, Ype P., and Clevers, Hans
- Abstract
The mammalian liver possesses a remarkable regenerative ability. Two modes of damage response have been described: (1) The "oval cell" response emanates from the biliary tree when all hepatocytes are affected by chronic liver disease. (2) A massive, proliferative response of mature hepatocytes occurs upon acute liver damage such as partial hepatectomy (PHx). While the oval cell response has been captured in vitro by growing organoids cholangiocytes, the hepatocyte proliferative response has not been recapitulated in culture. Here, we describe the establishment of a long-term 3D rganoid culture system for mouse and human primary hepatocytes. Organoids can be established from single hepatocytes and grown for multiple months, while retaining key morphological, functional and gene expression features. Transcriptional profiles of the organoids resemble those of proliferating hepatocytes after PHx. Human hepatocyte organoids proliferate extensively after engraftment into mice and thus recapitulate the proliferative damage-response of hepatocytes.
- Published
- 2018
7. Modelling human embryogenesis: embryo-like structures spark ethical and policy debate.
- Author
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Daoud, Ana M Pereira, Popovic, Mina, Dondorp, Wybo J, Bustos, Marc Trani, Bredenoord, Annelien L, Lopes, Susana M Chuva de Sousa, Brink, Susanne C van den, Roelen, Bernard A J, Wert, Guido M W R de, Heindryckx, Björn, Pereira Daoud, Ana M, Trani Bustos, Marc, Chuva de Sousa Lopes, Susana M, van den Brink, Susanne C, and de Wert, Guido M W R
- Subjects
EMBRYOLOGY ,HUMAN biology ,PLURIPOTENT stem cells ,DEVELOPMENTAL biology ,HUMAN embryos - Abstract
Background: Studying the human peri-implantation period remains hindered by the limited accessibility of the in vivo environment and scarcity of research material. As such, continuing efforts have been directed towards developing embryo-like structures (ELS) from pluripotent stem cells (PSCs) that recapitulate aspects of embryogenesis in vitro. While the creation of such models offers immense potential for studying fundamental processes in both pre- and early post-implantation development, it also proves ethically contentious due to wide-ranging views on the moral and legal reverence due to human embryos. Lack of clarity on how to qualify and regulate research with ELS thus presents a challenge in that it may either limit this new field of research without valid grounds or allow it to develop without policies that reflect justified ethical concerns.Objective and Rationale: The aim of this article is to provide a comprehensive overview of the existing scientific approaches to generate ELS from mouse and human PSCs, as well as discuss future strategies towards innovation in the context of human development. Concurrently, we aim to set the agenda for the ethical and policy issues surrounding research on human ELS.Search Methods: The PubMed database was used to search peer-reviewed articles and reviews using the following terms: 'stem cells', 'pluripotency', 'implantation', 'preimplantation', 'post-implantation', 'blastocyst', 'embryoid bodies', 'synthetic embryos', 'embryo models', 'self-assembly', 'human embryo-like structures', 'artificial embryos' in combination with other keywords related to the subject area. The PubMed and Web of Science databases were also used to systematically search publications on the ethics of ELS and human embryo research by using the aforementioned keywords in combination with 'ethics', 'law', 'regulation' and equivalent terms. All relevant publications until December 2019 were critically evaluated and discussed.Outcomes: In vitro systems provide a promising way forward for uncovering early human development. Current platforms utilize PSCs in both two- and three-dimensional settings to mimic various early developmental stages, including epiblast, trophoblast and amniotic cavity formation, in addition to axis development and gastrulation. Nevertheless, much hinges on the term 'embryo-like'. Extension of traditional embryo frameworks to research with ELS reveals that (i) current embryo definitions require reconsideration, (ii) cellular convertibility challenges the attribution of moral standing on the basis of 'active potentiality' and (iii) meaningful application of embryo protective directives will require rethinking of the 14-day culture limit and moral weight attributed to (non-)viability. Many conceptual and normative (dis)similarities between ELS and embryos thus remain to be thoroughly elucidated.Wider Implications: Modelling embryogenesis holds vast potential for both human developmental biology and understanding various etiologies associated with infertility. To date, ELS have been shown to recapitulate several aspects of peri-implantation development, but critically, cannot develop into a fetus. Yet, concurrent to scientific innovation, considering the extent to which the use of ELS may raise moral concerns typical of human embryo research remains paramount. This will be crucial for harnessing the potential of ELS as a valuable research tool, whilst remaining within a robust moral and legal framework of professionally acceptable practices. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
8. ESHRE guideline: female fertility preservation.
- Author
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Preservation, The ESHRE Guideline Group on Female Fertility, Anderson, Richard A, Amant, Frédéric, Braat, Didi, D'Angelo, Arianna, Lopes, Susana M Chuva de Sousa, Demeestere, Isabelle, Dwek, Sandra, Frith, Lucy, Lambertini, Matteo, Maslin, Caroline, Moura-Ramos, Mariana, Nogueira, Daniela, Rodriguez-Wallberg, Kenny, and Vermeulen, Nathalie
- Subjects
FERTILITY preservation ,METHODOLOGY - Abstract
STUDY QUESTION What is the recommended management for women and transgender men with regards to fertility preservation (FP), based on the best available evidence in the literature? SUMMARY ANSWER The ESHRE Guideline on Female Fertility Preservation makes 78 recommendations on organization of care, information provision and support, pre-FP assessment, FP interventions and after treatment care. Ongoing developments in FP are also discussed. WHAT IS KNOWN ALREADY The field of FP has grown hugely in the last two decades, driven by the increasing recognition of the importance of potential loss of fertility as a significant effect of the treatment of cancer and other serious diseases, and the development of the enabling technologies of oocyte vitrification and ovarian tissue cryopreservation (OTC) for subsequent autografting. This has led to the widespread, though uneven, provision of FP for young women. STUDY DESIGN, SIZE, DURATION The guideline was developed according to the structured methodology for development of ESHRE guidelines. After formulation of key questions by a group of experts, literature searches and assessments were performed. Papers published up to 1 November 2019 and written in English were included in the review. PARTICIPANTS/MATERIALS, SETTING, METHODS Based on the collected evidence, recommendations were formulated and discussed until consensus was reached within the guideline group. A stakeholder review was organized after finalization of the draft. The final version was approved by the guideline group and the ESHRE Executive Committee. MAIN RESULTS AND THE ROLE OF CHANCE This guideline aims to help providers meet a growing demand for FP options by diverse groups of patients, including those diagnosed with cancer undergoing gonadotoxic treatments, with benign diseases undergoing gonadotoxic treatments or those with a genetic condition predisposing to premature ovarian insufficiency, transgender men (assigned female at birth), and women requesting oocyte cryopreservation for age-related fertility loss. The guideline makes 78 recommendations on information provision and support, pre-FP assessment, FP interventions and after treatment care, including 50 evidence-based recommendations—of which 31 were formulated as strong recommendations and 19 as weak—25 good practice points and 3 research only recommendations. Of the evidence-based recommendations, 1 was supported by high-quality evidence, 3 by moderate-quality evidence, 17 by low-quality evidence and 29 by very low-quality evidence. To support future research in the field of female FP, a list of research recommendations is provided. LIMITATIONS, REASONS FOR CAUTION Most interventions included are not well studied in FP patients. As some interventions, e.g. oocyte and embryo cryopreservation, are well established for treatment of infertility, technical aspects, feasibility and outcomes can be extrapolated. For other interventions, such as OTC and IVM, more evidence is required, specifically pregnancy outcomes after applying these techniques for FP patients. Such future studies may require the current recommendations to be revised. WIDER IMPLICATIONS OF THE FINDINGS The guideline provides clinicians with clear advice on best practice in female FP, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in FP. STUDY FUNDING/COMPETING INTEREST(S) The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive payment. R.A.A. reports personal fees and non-financial support from Roche Diagnostics, personal fees from Ferring Pharmaceuticals, IBSA and Merck Serono, outside the submitted work; D.B. reports grants from Merck Serono and Goodlife, outside the submitted work; I.D. reports consulting fees from Roche and speaker's fees from Novartis; M.L. reports personal fees from Roche, Novartis, Pfizer, Lilly, Takeda, and Theramex, outside the submitted work. The other authors have no conflicts of interest to declare. DISCLAIMER This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose. (Full disclaimer available at www.eshre.eu/guidelines.)
† ESHRE Pages content is not externally peer reviewed. The manuscript has been approved by the Executive Committee of ESHRE. [ABSTRACT FROM AUTHOR]- Published
- 2020
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- View/download PDF
9. Efficient Derivation of Basal Progenitor Cells from Human Pluripotent Stem Cells for Modeling Esophageal Development
- Author
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Zhang, Yongchun, primary, Yang, Ying, additional, Jiang, Ming, additional, Huang, Sarah Xuelian, additional, Mori, Munemasa, additional, Chen, Ya-Wen, additional, Balasubramanian, Revathi, additional, Kim, Eugene, additional, Lin, Sijie, additional, Toste de Carvalho, Ana Luisa Rodrigues, additional, Serra, Carlos, additional, Riccio, Paul N., additional, Bialecka, Monika, additional, Lopes, Susana M. Chuva de Sousa, additional, Cardoso, Wellington, additional, Zhang, Xin, additional, Snoeck, Hans-Willem, additional, and Que, Jianwen, additional
- Published
- 2018
- Full Text
- View/download PDF
10. Human blastocyst outgrowths recapitulate primordial germ cell specification events.
- Author
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Popovic, Mina, Bialecka, Monika, Fernandes, Maria Gomes, Taelman, Jasin, Jeught, Margot Van Der, Sutter, Petra De, Heindryckx, Björn, and Lopes, Susana M Chuva De Sousa
- Published
- 2019
- Full Text
- View/download PDF
11. Erratum: Kidney organoids from human iPS cells contain multiple lineages and model human nephrogenesis
- Author
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Takasato, Minoru, primary, Er, Pei X., additional, Chiu, Han S., additional, Maier, Barbara, additional, Baillie, Gregory J., additional, Ferguson, Charles, additional, Parton, Robert G., additional, Wolvetang, Ernst J., additional, Roost, Matthias S., additional, Lopes, Susana M. Chuva de Sousa, additional, and Little, Melissa H., additional
- Published
- 2016
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- View/download PDF
12. Characterization of migratory primordial germ cells in the aortagonad- mesonephros of a 4.5-week-old human embryo: a toolbox to evaluate in vitro early gametogenesis.
- Author
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Fernandes, Maria Gomes, Bialecka, Monika, Salvatori, Daniela C F, and Lopes, Susana M Chuva de Sousa
- Published
- 2018
- Full Text
- View/download PDF
13. Dynamic Equilibrium and Heterogeneity of Mouse Pluripotent Stem Cells with Distinct Functional and Epigenetic States
- Author
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Hayashi, Katsuhiko, primary, Lopes, Susana M. Chuva de Sousa, additional, Tang, Fuchou, additional, and Surani, M. Azim, additional
- Published
- 2008
- Full Text
- View/download PDF
14. Kidney organoids from human iPS cells contain multiple lineages and model human nephrogenesis.
- Author
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Takasato, Minoru, Er, Pei X., Chiu, Han S., Maier, Barbara, Baillie, Gregory J., Ferguson, Charles, Parton, Robert G., Wolvetang, Ernst J., Roost, Matthias S., Lopes, Susana M. Chuva de Sousa, and Little, Melissa H.
- Published
- 2016
- Full Text
- View/download PDF
15. Using micropatterning of hiPSCs to induce PGC formation
- Author
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Bretes, Francisco Vieira, Lopes, Susana M. Chuva de Sousa, and Rodrigues, Maria Gabriela,1965
- Subjects
hESCs ,PGC ,in vitro ,Micropadronização ,Ciências Naturais::Ciências Biológicas [Domínio/Área Científica] ,Gastrulação ,Teses de mestrado - 2019 ,hiPSC - Abstract
Tese de mestrado, Biologia Evolutiva e do Desenvolvimento, Universidade de Lisboa, Faculdade de Ciências, 2019 Submitted by Cristina Manessiez (camanessiez@fc.ul.pt) on 2020-01-30T17:35:50Z No. of bitstreams: 1 ulfc125705_tm_Francisco_Bretes.pdf: 4115423 bytes, checksum: 300ffce0991b3fdebe543355f18f79e7 (MD5) Made available in DSpace on 2020-01-30T17:36:01Z (GMT). No. of bitstreams: 1 ulfc125705_tm_Francisco_Bretes.pdf: 4115423 bytes, checksum: 300ffce0991b3fdebe543355f18f79e7 (MD5) Previous issue date: 2019
- Published
- 2019
16. Hitchhiking through the amnion/chorion: redefining the migratory route of primordial germ cells in chicken embryos
- Author
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Bernardo, Ana Isabel de Melo, 1988, Rodrigues, Maria Gabriela, 1965, and Lopes, Susana M. Chuva de Sousa
- Subjects
Desenvolvimento embrionário ,Marcadores celulares ,Embrião da galinha ,Teses de mestrado, 2011 ,Embriologia animal - Abstract
Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ciências, 2011 Submitted by Lurdes Saramago (lurdes.saramago@fc.ul.pt) on 2011-11-21T17:28:03Z No. of bitstreams: 1 ulfc090920_Ana_Bernardo.pdf: 3469178 bytes, checksum: f3ee07e8244ee3ff3f15263f19b274a3 (MD5) Made available in DSpace on 2011-11-21T17:28:41Z (GMT). No. of bitstreams: 1 ulfc090920_Ana_Bernardo.pdf: 3469178 bytes, checksum: f3ee07e8244ee3ff3f15263f19b274a3 (MD5) Previous issue date: 2011
- Published
- 2011
17. Dynamic of the X chromosome inactivation in humans
- Author
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Fernandes, Maria Miguel Gomes, 1987, Lopes, Susana M. Chuva de Sousa, and Pereira, Maria João Colares, 1952
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Teses de mestrado - 2011 ,Determinação sexual ,Expressão génica ,Cromossoma X ,Humanos - Abstract
Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ciências, 2011 Submitted by Lurdes Saramago (lurdes.saramago@fc.ul.pt) on 2011-11-21T18:57:01Z No. of bitstreams: 1 ulfc090918_Maria_Fernandes.pdf: 2814011 bytes, checksum: 7586b6652eb961c4dbd80022cb95b92c (MD5) Made available in DSpace on 2011-11-21T18:57:30Z (GMT). No. of bitstreams: 1 ulfc090918_Maria_Fernandes.pdf: 2814011 bytes, checksum: 7586b6652eb961c4dbd80022cb95b92c (MD5) Previous issue date: 2011
- Published
- 2011
18. Analysis of co-expression of OCT4, NANOG and SOX2 in pluripotent cells of the porcine embryo, in vivo and in vitro.
- Author
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du Puy L, Lopes SM, Haagsman HP, and Roelen BA
- Subjects
- Animals, Cell Differentiation, Cells, Cultured, Fluorescent Antibody Technique, Gene Expression, Humans, In Situ Hybridization, Keratin-18 genetics, Nanog Homeobox Protein, RNA, Messenger analysis, Reverse Transcriptase Polymerase Chain Reaction, Embryonic Stem Cells metabolism, Homeodomain Proteins genetics, Octamer Transcription Factor-3 genetics, Pluripotent Stem Cells metabolism, SOXB1 Transcription Factors genetics, Swine embryology
- Abstract
To derive porcine embryonic stem (ES) cell lines, the time window during which porcine embryos contain pluripotent cells that are predisposed to undifferentiated self-renewal in vitro must be identified. Therefore we first studied the spatial and temporal expression pattern of key factors in pluripotency and lineage segregation of blastocyst-stage porcine embryos between embryonic days (E) 6.5 and E10.5 using whole mount in situ hybridization, quantitative reverse transcription (RT)-PCR and whole mount immunofluorescence. Expression of NANOG and SOX2 was detected in both the ICM and epiblast, while OCT4 expression became restricted to the epiblast at E9.5. Surprisingly ICM and epiblast cells also expressed CK18. Consequently, growth factors which sustain the undifferentiated growth of human ES cells and mouse epiblast stem cells (EpiSCs) were tested for their ability to sustain undifferentiated self-renewal of porcine ICM and epiblast cells in vitro. Cultures of ICM cells resulted in a higher percentage of primary colonies with an ES-like morphology compared to primary cultures derived from epiblast cells. These undifferentiated colonies sustained expression of OCT4, NANOG, SOX2 and CK18. The expression of CK18 suggests that these cells are more similar to human ES cells and mouse EpiSCs than to mouse ES cells. Although undifferentiated cultures were maintained for limited passages, ICM and epiblast cultures rapidly differentiated into cell types of mesodermal, ectodermal, and endodermal origin, as characterized by RT-PCR. These results demonstrate that porcine ICM and epiblast cells can not be cultured in vitro with currently used human ES cell culture conditions. Importantly however, the trio of OCT4, NANOG and SOX2, which are known to form an autoregulatory network for pluripotency in other systems, are co-expressed also by porcine epiblasts, and by undifferentiated primary colonies in culture., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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- View/download PDF
19. A distinct expression pattern in mammalian testes indicates a conserved role for NANOG in spermatogenesis.
- Author
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Kuijk EW, de Gier J, Lopes SM, Chambers I, van Pelt AM, Colenbrander B, and Roelen BA
- Subjects
- Animals, Dogs, Homeodomain Proteins genetics, Humans, Male, Mice, Mice, Transgenic, Nanog Homeobox Protein, Reverse Transcriptase Polymerase Chain Reaction, Gene Expression Profiling, Homeodomain Proteins physiology, Spermatogenesis physiology, Testis metabolism
- Abstract
Background: NANOG is a key player in pluripotency and its expression is restricted to pluripotent cells of the inner cell mass, the epiblast and to primordial germ cells. Spermatogenesis is closely associated with pluripotency, because through this process highly specialized sperm cells are produced that contribute to the formation of totipotent zygotes. Nevertheless, it is unknown if NANOG plays a role in this process., Methodology/principal Findings: In the current study, NANOG expression was examined in testes of various mammals, including mouse and human. Nanog mRNA and NANOG protein were detected by RT-PCR, immunohistochemistry, and western blotting. Furthermore, eGFP expression was detected in the testis of a transgenic Nanog eGFP-reporter mouse. Surprisingly, although NANOG expression has previously been associated with undifferentiated cells with stem cell potential, expression in the testis was observed in pachytene spermatocytes and in the first steps of haploid germ cell maturation (spermiogenesis). Weak expression in type A spermatogonia was also observed., Conclusions: The findings of the current study strongly suggest a conserved role for NANOG in meiotic and post-meiotic stages of male germ cell development.
- Published
- 2010
- Full Text
- View/download PDF
20. Of stem cells and gametes: similarities and differences.
- Author
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Roelen BA and Lopes SM
- Subjects
- Animals, Epigenesis, Genetic, Gametogenesis, Humans, Pluripotent Stem Cells cytology, Pluripotent Stem Cells metabolism, Totipotent Stem Cells cytology, Totipotent Stem Cells metabolism, Germ Cells cytology, Germ Cells metabolism, Stem Cells cytology, Stem Cells metabolism
- Abstract
Fusion of a mammalian sperm cell with an oocyte will lead to the formation of a new organism. As this new organism develops, the cells that construct the organism gradually lose developmental competence and become differentiated, a process which is in part mediated via epigenetic modifications. These mechanisms include DNA methylation, histone tail modifications and association with Polycomb and Trithorax proteins. Several cells within the organism must however maintain or regain developmental competence while they are highly specialized. These are the primordial germ cells that form the gametes; the oocytes and sperm cells. In this review different epigenetic modifying mechanisms will be discussed as they occur in developing embryos. In addition, aspects of nuclear reprogramming that are likely to occur via removal of epigenetic modifications are important, and several epigenetic removal mechanisms are indeed also active in developing germ cells. In vivo, a pluripotent cell has the capacity to form gametes, but in vitro terminal gametogenesis has proven to be difficult. Although development of pluripotent cells to cells with the characteristics of early germ cells has been unequivocally demonstrated, creating the correct culture milieu that enables further maturation of these cells has as yet been futile.
- Published
- 2008
- Full Text
- View/download PDF
21. Receptor protein tyrosine phosphatase mu expression as a marker for endothelial cell heterogeneity; analysis of RPTPmu gene expression using LacZ knock-in mice.
- Author
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Koop EA, Lopes SM, Feiken E, Bluyssen HA, van der Valk M, Voest EE, Mummery CL, Moolenaar WH, and Gebbink MF
- Subjects
- Alleles, Animals, Arteries metabolism, Blotting, Northern, Blotting, Southern, Brain metabolism, Capillaries metabolism, Cell Adhesion, Cell Communication, DNA, Complementary metabolism, Endothelium, Vascular metabolism, Female, Genes, Reporter, Heterozygote, Lac Operon, Liver metabolism, Mice, Mice, Transgenic, Models, Genetic, Muscle, Skeletal metabolism, Myocardium metabolism, Phosphorylation, Receptor-Like Protein Tyrosine Phosphatases, Class 2, Spleen metabolism, Time Factors, Tissue Distribution, beta-Galactosidase metabolism, Gene Expression Regulation, Developmental, Protein Tyrosine Phosphatases biosynthesis, Protein Tyrosine Phosphatases genetics
- Abstract
The receptor-like protein tyrosine phosphatase mu (RPTPmu) belongs to the subfamily of meprin, A5, RPTPmu (MAM) domain-containing RPTPs, which are thought to play an important role in cell-cell adhesion mediated processes. The current study was designed to examine the expression pattern of RPTPmu in mice. We have generated RPTPmu-LacZ knock-in mice that express the beta-galactosidase (LacZ) reporter gene under the control of the RPTPmu promoter. LacZ expression patterns were analysed in embryos and adult mice by whole mount LacZ staining. Analysis of beta-galactosidase activity of heterozygous embryos and adult tissues revealed RPTPmu expression in endothelial cells of arteries and capillaries. In contrast, expression was virtually absent in endothelial cells of veins and in fenestrated endothelial cells in the adult liver and spleen. Moreover, RPTPmu expression was found in endothelial cells from the endocardium and the aorta in embryos, but not in adult mice. In addition to heterogeneous expression in endothelial cells, RPTPmu expression was found in cardiac muscle cells but not in skeletal muscle cells or smooth muscle cells. Expression was also found in Type II pneumonocytes in the lung alveoli and in Purkinje cells and other neurons in the brain. The specific expression of RPTPmu in arterial endothelial cells and in cardiac myocytes suggests that RPTPmu may play a role in the regulation of cardiovascular functions.
- Published
- 2003
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