51
|
Truman AM, Tilly JL, Woods DC. Ovarian regeneration: The potential for stem cell contribution in the postnatal ovary to sustained endocrine function. Mol Cell Endocrinol 2017; 445:74-84. [PMID: 27743990 PMCID: PMC5604433 DOI: 10.1016/j.mce.2016.10.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/26/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023]
Abstract
The endocrine function of the ovary is dependent upon the ovarian follicle, which on a cellular basis consists of an oocyte surrounded by adjacent somatic cells responsible for generating sex steroid hormones and maintenance of hormonal stasis with the hypothalamic-pituitary axis. As females age, both fertility and the endocrine function of the ovary decline due to waning follicle numbers as well as aging-related cellular dysfunction. Although there is currently no cure for ovarian failure and endocrine disruption, recent advances in ovarian biology centered on ovarian stem cell and progenitor cell populations have brought the prospects of cell- or tissue-based therapeutic strategies closer to fruition. Herein, we review the relative contributions of ovarian stem cells to ovarian function during the reproductive lifespan, and postulate steps toward the development of ovarian stem cell-based approaches to advance fertility treatments, and also importantly to provide a physiological long-term means of endocrine support.
Collapse
Affiliation(s)
- Alisha M Truman
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA, USA
| | - Jonathan L Tilly
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA, USA
| | - Dori C Woods
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA, USA.
| |
Collapse
|
52
|
Chen D, Gell JJ, Tao Y, Sosa E, Clark AT. Modeling human infertility with pluripotent stem cells. Stem Cell Res 2017; 21:187-192. [PMID: 28431857 DOI: 10.1016/j.scr.2017.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 03/23/2017] [Accepted: 04/11/2017] [Indexed: 11/25/2022] Open
Abstract
Human fertility is dependent upon the correct establishment and differentiation of the germline. This is because no other cell type in the body is capable of passing a genome and epigenome from parent to child. Terminally differentiated germline cells in the adult testis and ovary are called gametes. However, the initial specification of germline cells occurs in the embryo around the time of gastrulation. Most of our knowledge regarding the cell and molecular events that govern human germline specification involves extrapolating scientific principles from model organisms, most notably the mouse. However, recent work using next generation sequencing, gene editing and differentiation of germline cells from pluripotent stem cells has revealed that the core molecular mechanisms that regulate human germline development are different from rodents. Here, we will discuss the major molecular pathways required for human germline differentiation and how pluripotent stem cells have revolutionized our ability to study the earliest steps in human embryonic lineage specification in order to understand human fertility.
Collapse
Affiliation(s)
- Di Chen
- Department of Molecular, Cell and Developmental Biology, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Los Angeles, CA 90095, USA; University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Joanna J Gell
- Department of Pediatrics, Division of Hematology/Oncology, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Los Angeles, CA 90095, USA; David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Yu Tao
- Department of Molecular, Cell and Developmental Biology, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Los Angeles, CA 90095, USA; University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Enrique Sosa
- Department of Molecular, Cell and Developmental Biology, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Los Angeles, CA 90095, USA; University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Amander T Clark
- Department of Molecular, Cell and Developmental Biology, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Los Angeles, CA 90095, USA; University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
53
|
Mechanisms of Vertebrate Germ Cell Determination. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:383-440. [PMID: 27975276 DOI: 10.1007/978-3-319-46095-6_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Two unique characteristics of the germ line are the ability to persist from generation to generation and to retain full developmental potential while differentiating into gametes. How the germ line is specified that allows it to retain these characteristics within the context of a developing embryo remains unknown and is one focus of current research. Germ cell specification proceeds through one of two basic mechanisms: cell autonomous or inductive. Here, we discuss how germ plasm driven germ cell specification (cell autonomous) occurs in both zebrafish and the frog Xenopus. We describe the segregation of germ cells during embryonic development of solitary and colonial ascidians to provide an evolutionary context to both mechanisms. We conclude with a discussion of the inductive mechanism as exemplified by both the mouse and axolotl model systems. Regardless of mechanism, several general themes can be recognized including the essential role of repression and posttranscriptional regulation of gene expression.
Collapse
|
54
|
Yamada M, De Chiara L, Seandel M. Spermatogonial Stem Cells: Implications for Genetic Disorders and Prevention. Stem Cells Dev 2016; 25:1483-1494. [PMID: 27596369 PMCID: PMC5035912 DOI: 10.1089/scd.2016.0210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Spermatogonial stem cells (SSCs) propagate mammalian spermatogenesis throughout male reproductive life by continuously self-renewing and differentiating, ultimately, into sperm. SSCs can be cultured for long periods and restore spermatogenesis upon transplantation back into the native microenvironment in vivo. Conventionally, SSC research has been focused mainly on male infertility and, to a lesser extent, on cell reprogramming. With the advent of genome-wide sequencing technology, however, human studies have uncovered a wide range of pathogenic alleles that arise in the male germ line. A subset of de novo point mutations was shown to originate in SSCs and cause congenital disorders in children. This review describes both monogenic diseases (eg, Apert syndrome) and complex disorders that are either known or suspected to be driven by mutations in SSCs. We propose that SSC culture is a suitable model for studying the origin and mechanisms of these diseases. Lastly, we discuss strategies for future clinical implementation of SSC-based technology, from detecting mutation burden by sperm screening to gene correction in vitro.
Collapse
Affiliation(s)
- Makiko Yamada
- Joan and Sanford I Weill Medical College of Cornell University, 12295, Surgery, New York, New York, United States ;
| | - Letizia De Chiara
- Joan and Sanford I Weill Medical College of Cornell University, 12295, Surgery, New York, New York, United States ;
| | - Marco Seandel
- Joan and Sanford I Weill Medical College of Cornell University, 12295, Surgery, New York, New York, United States ;
| |
Collapse
|
55
|
Bertocchini F, Chuva de Sousa Lopes SM. Germline development in amniotes: A paradigm shift in primordial germ cell specification. Bioessays 2016; 38:791-800. [PMID: 27273724 PMCID: PMC5089639 DOI: 10.1002/bies.201600025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the 'binary' evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes.
Collapse
Affiliation(s)
- Federica Bertocchini
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC)‐CSIC‐University of CantabriaSantanderSpain
| | - Susana M. Chuva de Sousa Lopes
- Department of Anatomy and EmbryologyLeiden University Medical CenterLeidenThe Netherlands
- Department of Reproductive MedicineGhent University HospitalGhentBelgium
| |
Collapse
|
56
|
Barton LJ, LeBlanc MG, Lehmann R. Finding their way: themes in germ cell migration. Curr Opin Cell Biol 2016; 42:128-137. [PMID: 27484857 DOI: 10.1016/j.ceb.2016.07.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/15/2016] [Accepted: 07/08/2016] [Indexed: 11/26/2022]
Abstract
Embryonic germ cell migration is a vital component of the germline lifecycle. The translocation of germ cells from the place of origin to the developing somatic gonad involves several processes including passive movements with underlying tissues, transepithelial migration, cell adhesion dynamics, the establishment of environmental guidance cues and the ability to sustain directed migration. How germ cells accomplish these feats in established model organisms will be discussed in this review, with a focus on recent discoveries and themes conserved across species.
Collapse
Affiliation(s)
- Lacy J Barton
- HHMI and Skirball Institute at NYU School of Medicine, 540 First Avenue, New York, NY 10016, United States
| | - Michelle G LeBlanc
- HHMI and Skirball Institute at NYU School of Medicine, 540 First Avenue, New York, NY 10016, United States
| | - Ruth Lehmann
- HHMI and Skirball Institute at NYU School of Medicine, 540 First Avenue, New York, NY 10016, United States.
| |
Collapse
|
57
|
Rosai J, Parkash V, Reuter VE. Invited Review : The Origin of Mediastinal Germ Cell Tumors in Men. Int J Surg Pathol 2016. [DOI: 10.1177/106689699400200112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mediastinal germ-cell tumors in men are generally thought to be primary at this site and to arise from extragonadal germ cells located in the thymus gland. Recent cytoge netic data have cast some doubt on this hypothesis and revived the alternative possibil ity of a testicular origin for these lesions. However, a review of the available evidence suggests that a primary mediastinal origin still remains the most likely explanation. The suggestion is made that the difficulties in identifying normal germ cells in the thymus gland may be due to their evolving into some type of somatic cell such as a myoid cell. Int J Surg Pathol 2(1):73-78, 1994
Collapse
|
58
|
Cantú AV, Altshuler-Keylin S, Laird DJ. Discrete somatic niches coordinate proliferation and migration of primordial germ cells via Wnt signaling. J Cell Biol 2016; 214:215-29. [PMID: 27402951 PMCID: PMC4949447 DOI: 10.1083/jcb.201511061] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/15/2016] [Indexed: 01/02/2023] Open
Abstract
Inheritance depends on the expansion of a small number of primordial germ cells (PGCs) in the early embryo. Proliferation of mammalian PGCs is concurrent with their movement through changing microenvironments; however, mechanisms coordinating these conflicting processes remain unclear. Here, we find that PGC proliferation varies by location rather than embryonic age. Ror2 and Wnt5a mutants with mislocalized PGCs corroborate the microenvironmental regulation of the cell cycle, except in the hindgut, where Wnt5a is highly expressed. Molecular and genetic evidence suggests that Wnt5a acts via Ror2 to suppress β-catenin-dependent Wnt signaling in PGCs and limit their proliferation in specific locations, which we validate by overactivating β-catenin in PGCs. Our results suggest that the balance between expansion and movement of migratory PGCs is fine-tuned in different niches by the opposing β-catenin-dependent and Ror2-mediated pathways through Wnt5a This could serve as a selective mechanism to favor early and efficient migrators with clonal dominance in the ensuing germ cell pool while penalizing stragglers.
Collapse
Affiliation(s)
- Andrea V Cantú
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94043
| | - Svetlana Altshuler-Keylin
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94043
| | - Diana J Laird
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94043
| |
Collapse
|
59
|
Grier HJ, Uribe MC, Lo Nostro FL, Mims SD, Parenti LR. Conserved form and function of the germinal epithelium through 500 million years of vertebrate evolution. J Morphol 2016; 277:1014-44. [DOI: 10.1002/jmor.20554] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/18/2016] [Accepted: 03/18/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Harry J. Grier
- Fish and Wildlife Research Institute; St. Petersburg Florida
- Department of Vertebrate Zoology; Division of Fishes; National Museum of Natural History, MRC 159, Smithsonian Institution; Washington DC
| | - Mari Carmen Uribe
- Laboratorio Biología de la Reproducción, Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México; Ciudad de México 04510 México
| | - Fabiana L. Lo Nostro
- Laboratorio de Ecotoxicología Acuática, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires & Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET-UBA, C1428EGA Buenos Aires; Argentina
| | - Steven D. Mims
- Aquaculture Research Center. Kentucky State University; Frankfort KY 40601
| | - Lynne R. Parenti
- Department of Vertebrate Zoology; Division of Fishes; National Museum of Natural History, MRC 159, Smithsonian Institution; Washington DC
| |
Collapse
|
60
|
Windley SP, Wilhelm D. Signaling Pathways Involved in Mammalian Sex Determination and Gonad Development. Sex Dev 2016; 9:297-315. [PMID: 26905731 DOI: 10.1159/000444065] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 11/19/2022] Open
Abstract
The development of any organ system requires a complex interplay of cellular signals to initiate the differentiation and development of the heterogeneous cell and tissue types required to carry out the organs' functions. In this way, an extracellular stimulus is transmitted to an intracellular target through an array of interacting protein intermediaries, ultimately enabling the target cell to elicit a response. Surprisingly, only a small number of signaling pathways are implicated throughout embryogenesis and are used over and over again. Gonadogenesis is a unique process in that 2 morphologically distinct organs, the testes and ovaries, arise from a common precursor, the bipotential genital ridge. Accordingly, most of the signaling pathways observed throughout embryogenesis also have been shown to be important for mammalian sex determination and gonad development. Here, we review the mechanisms of signal transduction within these pathways and the importance of these pathways throughout mammalian gonad development, mainly concentrating on data obtained in mouse but including other species where appropriate.
Collapse
Affiliation(s)
- Simon P Windley
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Vic., Australia
| | | |
Collapse
|
61
|
Diaz-Hernandez M, Hernandez F, Miras-Portugal MT, Avila J. TNAP Plays a Key Role in Neural Differentiation as well as in Neurodegenerative Disorders. Subcell Biochem 2016. [PMID: 26219721 DOI: 10.1007/978-94-017-7197-9_18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
New evidences have been reported that point to the ecto-enzyme, tissue-nonspecific alkaline phosphatase (TNAP), as a key element at the origin of two opposite phenomena, neuronal differentiation and neuronal degeneration. During brain development, TNAP plays an essential role for establishing neuronal circuits. The pro-neuritic effect induced by TNAP, which results in axonal length increase, is due to its enzymatic hydrolysis of extracellular ATP at the surrounding area of the axonal growth cone . In this way, the activation of P2X7 receptor is prevented and as a consequence there is no inhibition of axonal growth. The existence of a close functional interrelation between both purinergic elements is finally supported by the fact that both elements may control, in a reciprocal way, the expression level of the other. On the opposite stage, recent evidences indicate that TNAP plays a key role in spreading the neurotoxicity effect induced by extracellular hyperphosphorylated tau protein, the main component of intracellular neurofibrillary tangles present in the brain of Alzheimer disease patients. TNAP exhibits a broad substrate specificity and in addition to nucleotides it is able to dephosphorylate extracellular proteins, such as the hyperphosphorylated tau protein once it is released to the extracellular medium. Dephosphorylated tau protein behaves as an agonist of muscarinic M1 and M3 receptors, provoking a robust and sustained intracellular calcium increase that finally triggering neuronal death. Besides, activation of muscarinic receptors by dephosphorylated tau increases the expression of TNAP, which could explain the increase in TNAP activity and protein levels detected in Alzheimer disease.
Collapse
Affiliation(s)
- Miguel Diaz-Hernandez
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040, Madrid, Spain,
| | | | | | | |
Collapse
|
62
|
Gerovska D, Araúzo-Bravo MJ. Does mouse embryo primordial germ cell activation start before implantation as suggested by single-cell transcriptomics dynamics? Mol Hum Reprod 2016; 22:208-25. [PMID: 26740066 DOI: 10.1093/molehr/gav072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/07/2015] [Indexed: 12/19/2022] Open
Abstract
STUDY HYPOTHESIS Does primordial germ cell (PGC) activation start before mouse embryo implantation, and does the possible regulation of the DNA (cytosine-5-)-methyltransferase 3-like (Dnmt3l) by transcription factor AP-2, gamma (TCFAP2C) have a role in this activation and in the primitive endoderm (PE)-epiblast (EPI) lineage specification? STUDY FINDING A burst of expression of PGC markers, such as Dppa3/Stella, Ifitm2/Fragilis, Fkbp6 and Prdm4, is observed from embryonic day (E) 3.25, and some of them, together with the late germ cell markers Zp3, Mcf2 and Morc1, become restricted to the EPI subpopulation at E4.5, while the dynamics analysis of the PE-EPI transitions in the single-cell data suggests that TCFAP2C transitorily represses Dnmt3l in EPI cells at E3.5 and such repression is withdrawn with reactivation of Dnmt3l expression in PE and EPI cells at E4.5. WHAT IS KNOWN ALREADY In the mouse preimplantation embryo, cells with the same phenotype take different fates based on the orchestration between topological clues (cell polarity, positional history and division orientation) and gene regulatory rules (at transcriptomics and epigenomics level), prompting the proposal of positional, stochastic and combined models explaining the specification mechanism. PGC specification starts at E6.0-6.5 post-implantation. In view of the important role of DNA methylation in developmental events, the cross-talk between some transcription factors and DNA methyltransferases is of particular relevance. TCFAP2C has a CpG DNA methylation motif that is not methylated in pluripotent cells and that could potentially bind on DNMT3L, the stimulatory DNA methyltransferase co-factor that assists in the process of de novo DNA methylation. Chromatin-immunoprecipitation analysis has demonstrated that Dnmt3l is indeed a target of TCFAP2C. STUDY DESIGN, SAMPLES/MATERIALS, METHODS We aimed to assess the timing of early preimplantation events and to understand better the segregation of the inner cell mass (ICM) into PE and EPI. We designed a single-cell transcriptomics dynamics computational study to identify markers of the PE-EPI bifurcation in ICM cells through searching for statistically significant (using the Student's t-test method) differently expressed genes (DEGs) between PE and EPI cells from E3.5 to E4.5. The DEGs common for E3.5 and E4.5 were used as the markers defining the steady states. We collected microarray and next-generation sequencing transcriptomics data from public databases from bulk populations and single cells from mice at E3.25, E3.5 and E4.5. The results are based on three independent single-cell transcriptomics data sets, with a fold change of 3 and P-value <0.01 for the DEG selection. MAIN RESULTS AND THE ROLE OF CHANCE The dynamics analysis revealed new transitory E3.5 and steady PE and EPI markers. Among the transitory E3.5 PE markers (Dnmt3l, Dusp4, Cpne8, Akap13, Dcaf12l1, Aaed1, B4galt6, BC100530, Rnpc3, Tfpi, Lgalsl, Ckap4 and Fbxl20), several (Dusp4, Akap13, Cpn8, Dcaf12l1 and Tfpi) are related to the extracellular regulated kinase pathway. We also identified new transitory E3.5 EPI markers (Sgk1, Mal, Ubxn2a, Atg16l2, Gm13102, Tcfap2c, Hexb, Slc1a1, Svip, Liph and Mier3), six new stable PE markers (Sdc4, Cpn1, Dkk1, Havcr1, F2r/Par1 and Slc7a6os) as well as three new stable EPI markers (Zp3, Mcf2 and Hexb), which are known to be late stage germ cell markers. We found that mouse PGC marker activation starts at least at E3.25 preimplantation. The transcriptomics dynamics analyses support the regulation of Dnmt3l expression by TCFAP2C. LIMITATIONS, REASONS FOR CAUTION Since the regulation of Dnmt3l by TCFAP2C is based on computational prediction of DNA methylation motifs, Chip-Seq and transcriptomics data, functional studies are required to validate this result. WIDER IMPLICATIONS OF THE FINDINGS We identified a collection of previously undescribed E3.5-specific PE and EPI markers, and new steady PE and EPI markers. Identification of these genes, many of which encode cell membrane proteins, will facilitate the isolation and characterization of early PE and EPI populations. Since it is so well established in the literature that mouse PGC specification is a post-implantation event, it was surprising for us to see activation of PGC markers as early as E3.25 preimplantation, and identify the newly found steady EPI markers as late germ cell markers. The discovery of such early activation of PGC markers has important implications in the derivation of germ cells from pluripotent cells (embryonic stem cells or induced pluripotent stem cells), since the initial stages of such derivation resemble early development. The early activation of PGC markers points out the difficulty of separating PGC cells from pluripotent populations. Collectively, our results suggest that the combining of the precision of single-cell omics data with dynamic analysis of time-series data can establish the timing of some developmental stages as earlier than previously thought. LARGE-SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTERESTS This work was supported by grants DFG15/14 and DFG15/020 from Diputación Foral de Gipuzkoa (Spain), and grant II14/00016 from I + D + I National Plan 2013-2016 (Spain) and FEDER funds. The authors declare no conflict of interest.
Collapse
Affiliation(s)
- Daniela Gerovska
- Group of Computational Biology and Systems Biomedicine, Biodonostia Health Research Institute, Calle Doctor Beguiristain s/n, 20014 San Sebastián - Donostia, Spain
| | - Marcos J Araúzo-Bravo
- Group of Computational Biology and Systems Biomedicine, Biodonostia Health Research Institute, Calle Doctor Beguiristain s/n, 20014 San Sebastián - Donostia, Spain IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
63
|
De Felici M. The Formation and Migration of Primordial Germ Cells in Mouse and Man. Results Probl Cell Differ 2016; 58:23-46. [DOI: 10.1007/978-3-319-31973-5_2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
|
64
|
Abstract
Current knowledge on gonadal development and sex determination is the product of many decades of research involving a variety of scientific methods from different biological disciplines such as histology, genetics, biochemistry, and molecular biology. The earliest embryological investigations, followed by the invention of microscopy and staining methods, were based on histological examinations. The most robust development of histological staining techniques occurred in the second half of the nineteenth century and resulted in structural descriptions of gonadogenesis. These first studies on gonadal development were conducted on domesticated animals; however, currently the mouse is the most extensively studied species. The next key point in the study of gonadogenesis was the advancement of methods allowing for the in vitro culture of fetal gonads. For instance, this led to the description of the origin of cell lines forming the gonads. Protein detection using antibodies and immunolabeling methods and the use of reporter genes were also invaluable for developmental studies, enabling the visualization of the formation of gonadal structure. Recently, genetic and molecular biology techniques, especially gene expression analysis, have revolutionized studies on gonadogenesis and have provided insight into the molecular mechanisms that govern this process. The successive invention of new methods is reflected in the progress of research on gonadal development.
Collapse
Affiliation(s)
- Rafal P Piprek
- Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.
| |
Collapse
|
65
|
Teng Z, Wang C, Wang Y, Huang K, Xiang X, Niu W, Feng L, Zhao L, Yan H, Zhang H, Xia G. S100A8, An Oocyte-Specific Chemokine, Directs the Migration of Ovarian Somatic Cells During Mouse Primordial Follicle Assembly. J Cell Physiol 2015; 230:2998-3008. [PMID: 25953201 DOI: 10.1002/jcp.25032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/04/2015] [Indexed: 01/22/2023]
Abstract
In the mammalian ovaries, the primordial follicle pool determines the reproductive capability over the lifetime of a female. The primordial follicle is composed of two cell members, namely the oocyte and the pre-granulosa cells that encircle the oocyte. However, it is unclear what factors are involved in the reorganization of the two distinct cells into one functional unit. This study was performed to address this issue. Firstly, in an in vitro reconstruction system, dispersed ovarian cells from murine fetal ovaries at 19.0 days post coitum (dpc) reassembled into follicle-like structures, independent of the physical distance between the cells, implying that either oocytes or ovarian somatic cells (OSCs) were motile. We then carried out a series of transwell assay experiments, and determined that it was in fact 19.0 dpc OSCs (as opposed to oocytes), which exhibited a significant chemotactic response to both fetal bovine serum and oocytes themselves. We observed that S100A8, a multi-functional chemokine, may participate in the process as it is mainly expressed in oocytes within the cysts/plasmodia. S100A8 significantly promoted the number of migrating OSCs by 2.5 times in vitro, of which 66.9% were FOXL2 protein-positive cells, implying that the majority of motile OSCs were pre-granulosa cells. In addition, an S100A8-specific antibody inhibited the formation of follicle-like reconstruction cell mass in vitro. And, the primordial follicle formation was reduced when S100a8-specific siRNA was applied onto in vitro cultured 17.5 dpc ovary. Therefore, S100A8 could be a chemokine of oocyte origin, which attracts OSCs to form the primordial follicles.
Collapse
Affiliation(s)
- Zhen Teng
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Chao Wang
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Yijing Wang
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Kun Huang
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Xi Xiang
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Wanbao Niu
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Lizhao Feng
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Lihua Zhao
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Hao Yan
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Hua Zhang
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| | - Guoliang Xia
- State Key Laboratory of Agro-biotechnology, College of Biological Science, China Agricultural University, Beijing,, China
| |
Collapse
|
66
|
Nikolic A, Volarevic V, Armstrong L, Lako M, Stojkovic M. Primordial Germ Cells: Current Knowledge and Perspectives. Stem Cells Int 2015; 2016:1741072. [PMID: 26635880 PMCID: PMC4655300 DOI: 10.1155/2016/1741072] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/17/2015] [Indexed: 01/11/2023] Open
Abstract
Infertility is a condition that occurs very frequently and understanding what defines normal fertility is crucial to helping patients. Causes of infertility are numerous and the treatment often does not lead to desired pregnancy especially when there is a lack of functional gametes. In humans, the primordial germ cell (PGC) is the primary undifferentiated stem cell type that will differentiate towards gametes: spermatozoa or oocytes. With the development of stem cell biology and differentiation protocols, PGC can be obtained from pluripotent stem cells providing a new therapeutic possibility to treat infertile couples. Recent studies demonstrated that viable mouse pups could be obtained from in vitro differentiated stem cells suggesting that translation of these results to human is closer. Therefore, the aim of this review is to summarize current knowledge about PGC indicating the perspective of their use in both research and medical application for the treatment of infertility.
Collapse
Affiliation(s)
- Aleksandar Nikolic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 69 Svetozara Markovica Street, 34000 Kragujevac, Serbia
| | - Vladislav Volarevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 69 Svetozara Markovica Street, 34000 Kragujevac, Serbia
| | - Lyle Armstrong
- Institute of Genetic Medicine, Newcastle University, The International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, The International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Miodrag Stojkovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 69 Svetozara Markovica Street, 34000 Kragujevac, Serbia
- Spebo Medical, Norvezanska 16, 16 000 Leskovac, Serbia
| |
Collapse
|
67
|
Weissman I. Evolution of normal and neoplastic tissue stem cells: progress after Robert Hooke. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140364. [PMID: 26416675 PMCID: PMC4633993 DOI: 10.1098/rstb.2014.0364] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2015] [Indexed: 01/29/2023] Open
Abstract
The appearance of stem cells coincides with the transition from single-celled organisms to metazoans. Stem cells are capable of self-renewal as well as differentiation. Each tissue is maintained by self-renewing tissue-specific stem cells. The accumulation of mutations that lead to preleukaemia are in the blood-forming stem cell, while the transition to leukaemia stem cells occurs in the clone at a progenitor stage. All leukaemia and cancer cells escape being removed by scavenger macrophages by expressing the 'don't eat me' signal CD47. Blocking antibodies to CD47 are therapeutics for all cancers, and are currently being tested in clinical trials in the US and UK.
Collapse
Affiliation(s)
- Irving Weissman
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA Ludwig Center for Cancer Stem Cell Research and Medicine, Stanford University, Stanford, CA 94305, USA
| |
Collapse
|
68
|
Ferreira DW, Allard P. Models of germ cell development and their application for toxicity studies. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:637-49. [PMID: 25821157 PMCID: PMC4586303 DOI: 10.1002/em.21946] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/15/2015] [Accepted: 02/21/2015] [Indexed: 05/19/2023]
Abstract
Germ cells are unique in their ability to transfer genetic information and traits from generation to generation. As such, the proper development of germ cells and the integrity of their genome are paramount to the health of organisms and the survival of species. Germ cells are also exquisitely sensitive to environmental influences although the testing of germ cell toxicity, especially in females, has proven particularly challenging. In this review, we first describe the remarkable odyssey of germ cells in mammals, with an emphasis on the female germline, from their initial specification early during embryogenesis to the generation of mature gametes in adults. We also describe the current methods used in germ cell toxicity testing and their limitations in examining the complex features of mammalian germ cell development. To bypass these challenges, we propose the use of alternative model systems such as Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans, and in vitro germ cell methods that have distinct advantages over traditional toxicity models. We discuss the benefits and limitations of each approach, their application to germ cell toxicity studies, and the need for computational approaches to maximize the usefulness of these models. Together, the inclusion of these alternative germ cell toxicity models will be invaluable for the examination of stages not easily accessible in mammals as well as the large scale, high-throughput investigation of germ cell toxicity.
Collapse
Affiliation(s)
- Daniel W Ferreira
- Institute for Society and Genetics, Department of Environmental Health Sciences, University of California, Los Angeles, California
| | - Patrick Allard
- Institute for Society and Genetics, Department of Environmental Health Sciences, University of California, Los Angeles, California
| |
Collapse
|
69
|
Genetic mosaics and the germ line lineage. Genes (Basel) 2015; 6:216-37. [PMID: 25898403 PMCID: PMC4488662 DOI: 10.3390/genes6020216] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 03/27/2015] [Accepted: 04/07/2015] [Indexed: 12/26/2022] Open
Abstract
Genetic mosaics provide information about cellular lineages that is otherwise difficult to obtain, especially in humans. De novo mutations act as cell markers, allowing the tracing of developmental trajectories of all descendants of the cell in which the new mutation arises. De novo mutations may arise at any time during development but are relatively rare. They have usually been observed through medical ascertainment, when the mutation causes unusual clinical signs or symptoms. Mutational events can include aneuploidies, large chromosomal rearrangements, copy number variants, or point mutations. In this review we focus primarily on the analysis of point mutations and their utility in addressing questions of germ line versus somatic lineages. Genetic mosaics demonstrate that the germ line and soma diverge early in development, since there are many examples of combined somatic and germ line mosaicism for de novo mutations. The occurrence of simultaneous mosaicism in both the germ line and soma also shows that the germ line is not strictly clonal but arises from at least two, and possibly multiple, cells in the embryo with different ancestries. Whole genome or exome DNA sequencing technologies promise to expand the range of studies of genetic mosaics, as de novo mutations can now be identified through sequencing alone in the absence of a medical ascertainment. These technologies have been used to study mutation patterns in nuclear families and in monozygotic twins, and in animal model developmental studies, but not yet for extensive cell lineage studies in humans.
Collapse
|
70
|
Sebastián-Serrano Á, de Diego-García L, Martínez-Frailes C, Ávila J, Zimmermann H, Millán JL, Miras-Portugal MT, Díaz-Hernández M. Tissue-nonspecific Alkaline Phosphatase Regulates Purinergic Transmission in the Central Nervous System During Development and Disease. Comput Struct Biotechnol J 2014; 13:95-100. [PMID: 25709758 PMCID: PMC4334957 DOI: 10.1016/j.csbj.2014.12.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/04/2014] [Accepted: 12/10/2014] [Indexed: 02/02/2023] Open
Abstract
Tissue-nonspecific alkaline phosphatase (TNAP) is one of the four isozymes in humans and mice that have the capacity to hydrolyze phosphate groups from a wide spectrum of physiological substrates. Among these, TNAP degrades substrates implicated in neurotransmission. Transgenic mice lacking TNAP activity display the characteristic skeletal and dental phenotype of infantile hypophosphatasia, as well as spontaneous epileptic seizures and die around 10 days after birth. This physiopathology, linked to the expression pattern of TNAP in the central nervous system (CNS) during embryonic stages, suggests an important role for TNAP in neuronal development and synaptic function, situating it as a good target to be explored for the treatment of neurological diseases. In this review, we will focus mainly on the role that TNAP plays as an ectonucleotidase in CNS regulating the levels of extracellular ATP and consequently purinergic signaling.
Collapse
Affiliation(s)
- Álvaro Sebastián-Serrano
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, 28040 Madrid, Spain ; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Laura de Diego-García
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, 28040 Madrid, Spain ; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Carlos Martínez-Frailes
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, 28040 Madrid, Spain ; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Jesús Ávila
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Madrid, Spain
| | - Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, J. W. Goethe-University, Frankfurt 60438, Germany
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA, United States
| | - María Teresa Miras-Portugal
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, 28040 Madrid, Spain ; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Miguel Díaz-Hernández
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, 28040 Madrid, Spain ; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| |
Collapse
|
71
|
Abstract
Current dogma is that mouse primordial germ cells (PGCs) segregate within the allantois, or source of the umbilical cord, and translocate to the gonads, differentiating there into sperm and eggs. In light of emerging data on the posterior embryonic-extraembryonic interface, and the poorly studied but vital fetal-umbilical connection, we have reviewed the past century of experiments on mammalian PGCs and their relation to the allantois. We demonstrate that, despite best efforts and valuable data on the pluripotent state, what is and is not a PGC in vivo is obscure. Furthermore, sufficient experimental evidence has yet to be provided either for an extragonadal origin of mammalian PGCs or for their segregation within the posterior region. Rather, most evidence points to an alternative hypothesis that PGCs in the mouse allantois are part of a stem/progenitor cell pool that exhibits all known PGC "markers" and that builds/reinforces the fetal-umbilical interface, common to amniotes. We conclude by suggesting experiments to distinguish the mammalian germ line from the soma.
Collapse
|
72
|
Microanatomical Study of Embryonic Gonadal Development in Japanese Quail (Coturnix japonica). ANATOMY RESEARCH INTERNATIONAL 2014; 2014:168614. [PMID: 25276431 PMCID: PMC4168037 DOI: 10.1155/2014/168614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/21/2014] [Indexed: 01/20/2023]
Abstract
Gonadal development of quail embryos was examined histologically using histological and histochemical methods. In the present study, quail embryos were studied at various stages of incubation period based on phases of gonadogenesis. Germ cell migration was observed on day 3-4 but gonadal differentiation and gonadal function were observed on day 6-8 and day 11-14, respectively. During germ cell migration, quail primordial germ cells (qPGCs) were successfully detected in both left and right genital ridges as well as the dorsal mesentery by lectin histochemistry. Unexpectedly, qPGCs-like cells were found next to the neural tube by Mallory-AZAN stain. During gonadal differentiation, embryonic sex can be distinguished histologically since day 8 of incubation. Embryonic testis exhibited a thin cortex, whereas embryonic ovary exhibited a thick cortex. Testicular cord formation was found in the medulla of embryonic testes while the lacunae and fat-laden cells were found in the medulla of embryonic ovary during gonadal function. This is the first report on a comparison of phases of gonadogenesis and histochemical study of quail embryonic gonads in both sexes.
Collapse
|
73
|
Irie N, Tang WWC, Azim Surani M. Germ cell specification and pluripotency in mammals: a perspective from early embryogenesis. Reprod Med Biol 2014; 13:203-215. [PMID: 25298745 PMCID: PMC4182624 DOI: 10.1007/s12522-014-0184-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/19/2014] [Indexed: 12/01/2022] Open
Abstract
Germ cells are unique cell types that generate a totipotent zygote upon fertilization, giving rise to the next generation in mammals and many other multicellular organisms. How germ cells acquire this ability has been of considerable interest. In mammals, primordial germ cells (PGCs), the precursors of sperm and oocytes, are specified around the time of gastrulation. PGCs are induced by signals from the surrounding extra-embryonic tissues to the equipotent epiblast cells that give rise to all cell types. Currently, the mechanism of PGC specification in mammals is best understood from studies in mice. Following implantation, the epiblast cells develop as an egg cylinder while the extra-embryonic ectoderm cells which are the source of important signals for PGC specification are located over the egg cylinder. However, in most cases, including humans, the epiblast cells develop as a planar disc, which alters the organization and the source of the signaling for cell fates. This, in turn, might have an effect on the precise mechanism of PGC specification in vivo as well as in vitro using pluripotent embryonic stem cells. Here, we discuss how the key early embryonic differences between rodents and other mammals may affect the establishment of the pluripotency network in vivo and in vitro, and consequently the basis for PGC specification, particularly from pluripotent embryonic stem cells in vitro.
Collapse
Affiliation(s)
- Naoko Irie
- Wellcome Trust/Cancer Research UK, Gurdon InstituteUniversity of CambridgeTennis Court RoadCB2 1QNCambridgeUK
| | - Walfred W. C. Tang
- Wellcome Trust/Cancer Research UK, Gurdon InstituteUniversity of CambridgeTennis Court RoadCB2 1QNCambridgeUK
| | - M. Azim Surani
- Wellcome Trust/Cancer Research UK, Gurdon InstituteUniversity of CambridgeTennis Court RoadCB2 1QNCambridgeUK
| |
Collapse
|
74
|
Ramos-Ibeas P, Pericuesta E, Fernández-González R, Gutiérrez-Adán A, Ramírez MÁ. Germ-cell culture conditions facilitate the production of mouse embryonic stem cells. Mol Reprod Dev 2014; 81:794-804. [PMID: 24861201 DOI: 10.1002/mrd.22346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 05/21/2014] [Indexed: 11/10/2022]
Abstract
The derivation of embryonic stem-cell (ESC) lines from blastocysts is a very inefficient process. Murine ESCs are thought to arise from epiblast cells that are already predisposed to a primordial-germ-cell fate. During the process of ESC derivation from B6D2 F1 hybrid mice, if we first culture the embryo from the two-cell stage in medium supplemented with LIF, we improve the quality of the blastocyst. When the blastocyst is then cultured in a germ-line stem-cell culture medium (GSCm), we are able to more efficiently (28.3%) obtain quality ESC lines that have a normal karyotype, proper degree of chimerism, and exhibit germ-line transmission when microinjected into blastocysts. Although germ-cell-specific genes were expressed in all culture medium conditions, GSCm did not shift the transcriptome towards germ-cell specification. A correlation was further observed between ESC derivation efficiency and the expression of some imprinted genes and retrotransposable elements. In conclusion, the combination of LIF supplementation followed by culture in GSCm establishes a higher efficiency method for ESC derivation.
Collapse
|
75
|
Leitch HG, Tang WWC, Surani MA. Primordial germ-cell development and epigenetic reprogramming in mammals. Curr Top Dev Biol 2014; 104:149-87. [PMID: 23587241 DOI: 10.1016/b978-0-12-416027-9.00005-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Primordial germ cells (PGCs) are the embryonic precursors of the gametes and represent the founder cells of the germline. Specification of PGCs is a critical divergent point during embryogenesis. Whereas the somatic lineages will ultimately perish, cells of the germline have the potential to form a new individual and hence progress to the next generation. It is therefore critical that the genome emerges intact and carrying the appropriate epigenetic information during its passage through the germline. To ensure this fidelity of transmission, PGC development encompasses extensive epigenetic reprogramming. The low cell numbers and relative inaccessibility of PGCs present a challenge to those seeking mechanistic understanding of the crucial developmental and epigenetic processes in this most fascinating of lineages. Here, we present an overview of PGC development in the mouse and compare this with the limited information available for other mammalian species. We believe that a comparative approach will be increasingly important to uncover the extent to which mechanisms are conserved and reveal the critical steps during PGC development in humans.
Collapse
Affiliation(s)
- Harry G Leitch
- Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology, University of Cambridge, Cambridge, United Kingdom
| | | | | |
Collapse
|
76
|
Abstract
Primordial germ cells (PGCs) are the precursors of sperm and eggs, which generate a new organism that is capable of creating endless new generations through germ cells. PGCs are specified during early mammalian postimplantation development, and are uniquely programmed for transmission of genetic and epigenetic information to subsequent generations. In this Primer, we summarise the establishment of the fundamental principles of PGC specification during early development and discuss how it is now possible to make mouse PGCs from pluripotent embryonic stem cells, and indeed somatic cells if they are first rendered pluripotent in culture.
Collapse
Affiliation(s)
- Erna Magnúsdóttir
- Wellcome Trust, Cancer Research UK, Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | | |
Collapse
|
77
|
Jorgensen JS. Defining the neighborhoods that escort the oocyte through its early life events and into a functional follicle. Mol Reprod Dev 2013; 80:960-76. [PMID: 24105719 PMCID: PMC3980676 DOI: 10.1002/mrd.22232] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 08/15/2013] [Indexed: 01/19/2023]
Abstract
The ovary functions to chaperone the most precious cargo for female individuals, the oocyte, thereby allowing the passage of genetic material to subsequent generations. Within the ovary, single oocytes are surrounded by a legion of granulosa cells inside each follicle. These two cell types depend upon one another to support follicle formation and oocyte survival. The infrastructure and events that work together to ultimately form these functional follicles within the ovary are unprecedented, given that the oocyte originates as a cell like all other neighboring cells within the embryo prior to gastrulation. This review discusses the journey of the germ cell in the context of the developing female mouse embryo, with a focus on specific signaling events and cell-cell interactions that escort the primordial germ cell as it is specified into the germ cell fate, migrates through the hindgut into the gonad, differentiates into an oocyte, and culminates upon formation of the primordial and then primary follicle.
Collapse
Affiliation(s)
- Joan S Jorgensen
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| |
Collapse
|
78
|
Cong Y, Ma J, Sun R, Wang J, Xue B, Wang J, Xie B, Wang J, Hu K, Liu Z. Derivation of putative porcine embryonic germ cells and analysis of their multi-lineage differentiation potential. J Genet Genomics 2013; 40:453-64. [PMID: 24053947 DOI: 10.1016/j.jgg.2013.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 01/22/2023]
Abstract
Embryonic germ (EG) cells are cultured pluripotent stem cells derived from the primordial germ cells (PGCs) that migrate from the dorsal mesentery of the hindgut to the developing genital ridge. In this study, the morphology of the porcine genital ridge was assessed in embryos harvested on days 22-30 of pregnancy. PGCs from embryos at these stages were cultured to obtain porcine EG cell lines, and EG-like cells were derived from PGCs from embryos harvested on days 24-28 of pregnancy. The EG-like cells expressed Oct4, Sox2, Nanog, SSEA-3, SSEA-4 and alkaline phosphatase (AP). These cells were able to form embryoid bodies (EBs) in suspension culture and differentiate into cells representative of the three germ layers as verified by a-fetoprotein (AFP), α-smooth muscle actin (α-SMA), and Nestin expression. Spontaneous differentiation from the porcine EG-like cells of delayed passage in vitro showed that they could differentiate into epithelial-like cells, mesenchymal-like cells and neuron-like cells. In vitro directed differentiation generated osteocytes, adipocytes and a variety of neural lineage cells, as demonstrated by alizarin red staining, oil red O staining, and immunofluorescence for neuronal class Ⅲ β-tubulin (Tuj1), glial fibrillary protein (GFAP) and galactosylceramidase (GALC), respectively. These results indicate that porcine EG-like cells have the potential for multi-lineage differentiation and are useful for basic porcine stem cell research.
Collapse
Affiliation(s)
- Yimei Cong
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
79
|
|
80
|
Mikedis MM, Downs KM. Widespread but tissue-specific patterns of interferon-induced transmembrane protein 3 (IFITM3, FRAGILIS, MIL-1) in the mouse gastrula. Gene Expr Patterns 2013; 13:225-39. [PMID: 23639725 DOI: 10.1016/j.gep.2013.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 04/16/2013] [Accepted: 04/19/2013] [Indexed: 10/26/2022]
Abstract
Interferon-induced transmembrane protein 3 (IFITM3; FRAGILIS; MIL-1) is part of a larger family of important small interferon-induced transmembrane genes and proteins involved in early development, cell adhesion, and cell proliferation, and which also play a major role in response to bacterial and viral infections and, more recently, in pronounced malignancies. IFITM3, together with tissue-nonspecific alkaline phosphatase (TNAP), PRDM1, and STELLA, has been claimed to be a hallmark of segregated primordial germ cells (PGCs) (Saitou et al., 2002). However, whether IFITM3, like STELLA, is part of a broader stem/progenitor pool that builds the posterior region of the mouse conceptus (Mikedis and Downs, 2012) is obscure. To discover the whereabouts of IFITM3 during mouse gastrulation (~E6.5-9.0), systematic immunohistochemical analysis was carried out at closely spaced 2-4-h intervals. Results revealed diverse, yet consistent, profiles of IFITM3 localization throughout the gastrula. Within the putative PGC trajectory and surrounding posterior tissues, IFITM3 localized as a large cytoplasmic spot with or without staining in the plasma membrane. IFITM3, like STELLA, was also found in the ventral ectodermal ridge (VER), a posterior progenitor pool that builds the tailbud. The large cytoplasmic spot with plasma membrane staining was exclusive to the posterior region; the visceral yolk sac, non-posterior tissues, and epithelial tissues exhibited spots of IFITM3 without cell surface staining. Colocalization of the intracellular IFITM3 spot with the endoplasmic reticulum, Golgi apparatus, or endolysosomes was not observed. That relatively high levels of IFITM3 were found throughout the posterior primitive streak and its derivatives is consistent with evidence that IFITM3, like STELLA, is part of a larger stem/progenitor cell pool at the posterior end of the primitive streak that forms the base of the allantois and builds the fetal-umbilical connection, thus further obfuscating practical phenotypic distinctions between so-called PGCs and surrounding soma.
Collapse
Affiliation(s)
- Maria M Mikedis
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | | |
Collapse
|
81
|
Seervai RNH, Wessel GM. Lessons for inductive germline determination. Mol Reprod Dev 2013; 80:590-609. [PMID: 23450642 DOI: 10.1002/mrd.22151] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 01/03/2013] [Indexed: 12/25/2022]
Abstract
Formation of the germline in an embryo marks a fresh round of reproductive potential, yet the developmental stage and location within the embryo where the primordial germ cells (PGCs) form differs wildly among species. In most animals, the germline is formed either by an inherited mechanism, in which maternal provisions within the oocyte drive localized germ-cell fate once acquired in the embryo, or an inductive mechanism that involves signaling between cells that directs germ-cell fate. The inherited mechanism has been widely studied in model organisms such as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis, and Danio rerio. Given the rapid generation time and the effective adaptation for laboratory research of these organisms, it is not coincidental that research on these organisms has led the field in elucidating mechanisms for germline specification. The inductive mechanism, however, is less well understood and is studied primarily in the mouse (Mus musculus). In this review, we compare and contrast these two fundamental mechanisms for germline determination, beginning with the key molecular determinants that play a role in the formation of germ cells across all animal taxa. We next explore the current understanding of the inductive mechanism of germ-cell determination in mice, and evaluate the hypotheses for selective pressures on these contrasting mechanisms. We then discuss the hypothesis that the transition between these determination mechanisms, which has happened many times in phylogeny, is more of a continuum than a binary change. Finally, we propose an analogy between germline determination and sex determination in vertebrates-two of the milestones of reproduction and development-in which animals use contrasting strategies to activate similar pathways.
Collapse
Affiliation(s)
- Riyad N H Seervai
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, 02192, USA
| | | |
Collapse
|
82
|
Abstract
Germ cell development creates totipotency through genetic as well as epigenetic regulation of the genome function. Primordial germ cells (PGCs) are the first germ cell population established during development and are immediate precursors for both the oocytes and spermatogonia. We here summarize recent findings regarding the mechanism of PGC development in mice. We focus on the transcriptional and signaling mechanism for PGC specification, potential pluripotency, and epigenetic reprogramming in PGCs and strategies for the reconstitution of germ cell development using pluripotent stem cells in culture. Continued studies on germ cell development may lead to the generation of totipotency in vitro, which should have a profound influence on biological science as well as on medicine.
Collapse
Affiliation(s)
- Mitinori Saitou
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Japan.
| | | |
Collapse
|
83
|
Sabour D, Schöler HR. Reprogramming and the mammalian germline: the Weismann barrier revisited. Curr Opin Cell Biol 2012; 24:716-23. [PMID: 22947493 DOI: 10.1016/j.ceb.2012.08.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 08/08/2012] [Accepted: 08/20/2012] [Indexed: 01/17/2023]
Abstract
The germline represents a unique cell type that can transmit genetic material to the next generation. During early embryonic development, somatic cells give rise to a small population of cells known as germ cells, which eventually differentiate into mature gametes. Germ cells undergo a process of removing and resetting relevant epigenetic information, mainly by DNA demethylation. This extensive epigenetic reprogramming leads to the conversion of germ cells into immortal cells that can pass on the genome to the next generation. In the absence of germline-specific reprogramming, germ cells would preserve the old, parental epigenetic memory, which would prevent the transfer of heritable information to the offspring. On the contrary, somatic cells cannot reset epigenetic information by preserving the full methylation pattern on imprinting genes. In this review, we focus on the capacity of germ cells and somatic cells (soma) to transfer genetic information to the next generation, and thus revisit the Weismann theory of heredity.
Collapse
Affiliation(s)
- Davood Sabour
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, D-48149 Münster, Germany
| | | |
Collapse
|
84
|
Mikedis MM, Downs KM. STELLA-positive subregions of the primitive streak contribute to posterior tissues of the mouse gastrula. Dev Biol 2012; 363:201-18. [PMID: 22019303 PMCID: PMC3288210 DOI: 10.1016/j.ydbio.2011.10.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 08/26/2011] [Accepted: 10/02/2011] [Indexed: 11/21/2022]
Abstract
The developmental relationship between the posterior embryonic and extraembryonic regions of the mammalian gastrula is poorly understood. Although many different cell types are deployed within this region, only the primordial germ cells (PGCs) have been closely studied. Recent evidence has suggested that the allantois, within which the PGCs temporarily take up residence, contains a pool of cells, called the Allantoic Core Domain (ACD), critical for allantoic elongation to the chorion. Here, we have asked whether the STELLA-positive cells found within this region, thought to be specified PGCs, are actually part of the ACD and to what extent they, and other ACD cells, contribute to the allantois and fetal tissues. To address these hypotheses, STELLA was immunolocalized to the mouse gastrula between Early Streak (ES) and 12-somite pair (-s) stages (~6.75-9.0 days post coitum, dpc) in histological sections. STELLA was found in both the nucleus and cytoplasm in a variety of cell types, both within and outside of the putative PGC trajectory. Fate-mapping the headfold-stage (~7.75-8.0 dpc) posterior region, by which time PGCs are thought to be segregated into a distinct lineage, revealed that the STELLA-positive proximal ACD and intraembryonic posterior primitive streak (IPS) contributed to a wide range of somatic tissues that encompassed derivatives of the three primary germ layers. This contribution included STELLA-positive cells localizing to tissues both within and outside of the putative PGC trajectory. Thus, while STELLA may identify a subpopulation of cells destined for the PGC lineage, our findings reveal that it may be part of a broader niche that encompasses the ACD and through which the STELLA population may contribute cells to a wide variety of posterior tissues of the mouse gastrula.
Collapse
Affiliation(s)
- Maria M. Mikedis
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Ave, Madison, WI 53706, Tel: 608-265-5411, Fax: 608-262-7306
| | - Karen M. Downs
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Ave, Madison, WI 53706, Tel: 608-265-5411, Fax: 608-262-7306
| |
Collapse
|
85
|
Hopf C, Viebahn C, Püschel B. BMP signals and the transcriptional repressor BLIMP1 during germline segregation in the mammalian embryo. Dev Genes Evol 2011; 221:209-23. [PMID: 21881976 PMCID: PMC3192270 DOI: 10.1007/s00427-011-0373-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 07/28/2011] [Indexed: 11/26/2022]
Abstract
Molecular factors and tissue compartments involved in the foundation of the mammalian germline have been mainly described in the mouse so far. To find mechanisms applicable to mammals in general, we analyzed temporal and spatial expression patterns of the transcriptional repressor BLIMP1 (also known as PRDM1) and the signaling molecules BMP2 and BMP4 in perigastrulation and early neurulation embryos of the rabbit using whole-mount in situ hybridization and high-resolution light microscopy. Both BMP2 and BMP4 are expressed in annular domains at the boundary of the embryonic disc, which—in contrast to the situation in the mouse—partly belong to intraembryonic tissues. While BMP2 expression begins at (pregastrulation) stage 1 in the hypoblast, BMP4 expression commences—distinctly delayed compared to the mouse—diffusely at (pregastrulation) stage 2; from stage 3 onwards, BMP4 is expressed peripherally in hypoblast and epiblast and in the mesoderm at the posterior pole of the embryonic disc. BLIMP1 expression begins throughout the hypoblast at stage 1 and emerges in single primordial germ cell (PGC) precursors in the posterior epiblast at stage 2 and then in single mesoderm cells at positions identical to those identified by PGC-specific antibodies. These expression patterns suggest that function and chronology of factors involved in germline segregation are similar in mouse and rabbit, but higher temporal and spatial resolution offered by the rabbit demonstrates a variable role of bone morphogenetic proteins and makes “blimping” a candidate case for lateral inhibition without the need for an allantoic germ cell niche.
Collapse
Affiliation(s)
- Clas Hopf
- Department of Anatomy and Embryology, Center of Anatomy, Georg-August-University Göttingen, Kreuzbergring 36, 37075 Göttingen, Germany
| | - Christoph Viebahn
- Department of Anatomy and Embryology, Center of Anatomy, Georg-August-University Göttingen, Kreuzbergring 36, 37075 Göttingen, Germany
| | - Bernd Püschel
- Department of Anatomy and Embryology, Center of Anatomy, Georg-August-University Göttingen, Kreuzbergring 36, 37075 Göttingen, Germany
| |
Collapse
|
86
|
Julaton VTA, Reijo Pera RA. NANOS3 function in human germ cell development. Hum Mol Genet 2011; 20:2238-50. [PMID: 21421998 PMCID: PMC3090199 DOI: 10.1093/hmg/ddr114] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/15/2011] [Indexed: 11/29/2022] Open
Abstract
Human infertility is common and frequently linked to poor germ cell development. Yet, human germ cell development is poorly understood, at least in part due to the inaccessibility of germ cells to study especially during fetal development. Here, we explored the function of a highly conserved family of genes, the NANOS genes, in the differentiation of human germ cells from human embryonic stem cells. We observed that NANOS-1, -2 and -3 mRNAs and proteins were expressed in human gonads. We also noted that NANOS3 was expressed in germ cells throughout spermatogenesis and oogenesis and thus, focused further efforts on this family member. NANOS3 expression was highest in human germ cell nuclei where the protein co-localized with chromosomal DNA during mitosis/meiosis. Reduced expression of NANOS3 (via morpholinos or short hairpin RNA) resulted in a reduction in germ cell numbers and decreased expression of germ cell-intrinsic genes required for the maintenance of pluripotency and meiotic initiation and progression. These data provide the first direct experimental evidence that NANOS3 functions in human germ cell development; indeed, NANOS3 is now one of just two genes that has been directly shown to function in germ cell development across diverse species from flies, worms, frogs and mice to humans [the other is BOULE, a member of the Deleted in Azoospermia (DAZ) gene family]. Findings may contribute to our understanding of the basic biology of human germ cell development and may provide clinical insights regarding infertility.
Collapse
Affiliation(s)
| | - Renee A. Reijo Pera
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford University, Palo Alto, CA 94305, USA
| |
Collapse
|
87
|
Pelosi E, Forabosco A, Schlessinger D. Germ cell formation from embryonic stem cells and the use of somatic cell nuclei in oocytes. Ann N Y Acad Sci 2011; 1221:18-26. [PMID: 21401625 DOI: 10.1111/j.1749-6632.2011.05982.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Embryonic stem cells (ESCs) have remarkable properties of pluripotency and self-renewal, along with the retention of chromosomal integrity. Germ cells function as a kind of "transgenerational stem cells," transmitting genetic information from one generation to the next. The formation of putative primordial germ cells (PGCs) and germ cells from mouse and human ESCs (hESCs) has, in fact, been shown, and the apparent derivation of functional mouse male gametes has also been described. Additionally, investigators have successfully reprogrammed somatic nuclei into a pluripotent state by inserting them into ESCs or oocytes. This would enable the generation of ESCs genetically identical to the somatic cell donor and their use in cell therapy. However, these methodologies are still inefficient and their mechanisms poorly understood. Until full comprehension of these processes is obtained, clinical applications remain remote. Nevertheless, they represent promising tools in the future, enhancing methods of therapeutic cloning and infertility treatment.
Collapse
Affiliation(s)
- Emanuele Pelosi
- Laboratory of Genetics, National Institute on Aging/NIH Intramural Research Program, Baltimore, Maryland, USA.
| | | | | |
Collapse
|
88
|
Stoop H, Kirkels W, Dohle GR, Gillis AJM, den Bakker MA, Biermann K, Oosterhuis W, Looijenga LHJ. Diagnosis of testicular carcinoma in situ‘(intratubular and microinvasive)’ seminoma and embryonal carcinoma using direct enzymatic alkaline phosphatase reactivity on frozen histological sections. Histopathology 2011; 58:440-6. [DOI: 10.1111/j.1365-2559.2011.03767.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
89
|
Daane JM, Enders AC, Downs KM. Mesothelium of the murine allantois exhibits distinct regional properties. J Morphol 2011; 272:536-56. [PMID: 21284019 DOI: 10.1002/jmor.10928] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/18/2010] [Accepted: 10/25/2010] [Indexed: 11/06/2022]
Abstract
The rodent allantois is thought to be unique amongst mammals in not having an endodermal component. Here, we have investigated the mesothelium, or outer surface, of murine umbilical precursor tissue, the allantois (∼7.25-8.5 days postcoitum, dpc) to discover whether it exhibits the properties of an epithelium. A combination of morphology, challenge with biotinylated dextran amines (BDAs), and immunohistochemistry revealed that the mesothelium of the mouse allantois exhibits distinct regional properties. By headfold stages (∼7.75-8.0 dpc), distal mesothelium was generally squamous in shape, and highly permeable to BDA challenge, whereas ventral proximal mesothelium, referred to as "ventral cuboidal mesothelium" (VCM) for the characteristic cuboidal shape of its cells, was relatively impermeable. Although "dorsal cuboidal mesothelium" (DCM) resembled the VCM in cell shape, its permeability to BDA was intermediate between the other two regions. Results of immunostaining for Zonula Occludens-1 (ZO-1) and Epithelial-cadherin (E-cadherin), together with transmission electron microscopy (TEM), suggested that impermeability in the VCM may be due to greater cellular contact area between cells and close packing rather than to maturity of tight junctions, the latter of which, by comparison with the visceral yolk sac, appeared to be rare or absent from the allantoic surface. Both VCM and DCM exhibited an ultrastructure more favorable for protein synthesis than did the distal squamous mesothelium; however, at most stages, VCM exhibited robust afadin (AF-6), whereas the DCM uniquely contained alpha-4-integrin. These observations demonstrate that the allantoic mesothelium is not a conventional epithelium but possesses regional ultrastructural, functional and molecular differences that may play important roles in the correct deployment of the umbilical cord and its associated vascular, hematopoietic, and other cell types.
Collapse
Affiliation(s)
- Jacob M Daane
- Department of Anatomy, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | | | | |
Collapse
|
90
|
Abstract
The germ cell lineage is our lifelong reservoir of reproductive stem cells and our mechanism for transmitting genes to future generations. These highly specialised cells are specified early during development and then migrate to the embryonic gonads where sex differentiation occurs. Germ cell sex differentiation is directed by the somatic gonadal environment and is characterised by two distinct cell cycle states that are maintained until after birth. In the mouse, XY germ cells in a testis cease mitotic proliferation and enter G(1)/G(0) arrest from 12.5 dpc, while XX germ cells in an ovary enter prophase I of meiosis from 13.5 dpc. This chapter discusses the factors known to control proliferation and survival of germ cells during their journey of specification to sex differentiation during development.
Collapse
Affiliation(s)
- Cassy M Spiller
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | | |
Collapse
|
91
|
Sabour D, Araúzo-Bravo MJ, Hübner K, Ko K, Greber B, Gentile L, Stehling M, Schöler HR. Identification of genes specific to mouse primordial germ cells through dynamic global gene expression. Hum Mol Genet 2010; 20:115-25. [PMID: 20940145 DOI: 10.1093/hmg/ddq450] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Molecular mechanisms underlying the commitment of cells to the germ cell lineage during mammalian embryogenesis remain poorly understood due to the limited availability of cellular materials to conduct in vitro analyses. Although primordial germ cells (PGCs)--precursors to germ cells--have been generated from embryonic stem cells (ESCs)--pluripotent stem cells derived from the inner cell mass of the blastocyst of the early embryo in vitro-the simultaneous expression of cell surface receptors and transcription factors complicates the detection of PGCs. To date, only a few genes that mark the onset of germ cell commitment in the epiblast--the outer layer of cells of the embryo--including tissue non-specific alkaline phosphatase (TNAP), Blimp1, Stella and Fragilis--have been used with some success to detect PGC formation in in vitro model systems. Here, we identified 11 genes (three of which are novel) that are specifically expressed in male and female fetal germ cells, both in vivo and in vitro, but are not expressed in ESCs. Expression of these genes allows us to distinguish committed germ cells from undifferentiated pluripotent cell populations, a prerequisite for the successful derivation of germ cells and gametes in vitro.
Collapse
Affiliation(s)
- Davood Sabour
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | | | | | | | | | | | | | | |
Collapse
|
92
|
Simon L, Hess RA, Cooke PS. Spermatogonial stem cells, in vivo transdifferentiation and human regenerative medicine. Expert Opin Biol Ther 2010; 10:519-30. [PMID: 20146635 DOI: 10.1517/14712591003614731] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
IMPORTANCE OF THE FIELD Embryonic stem (ES) cells have potential for use in regenerative medicine, but use of these cells is hindered by moral, legal and ethical issues. Induced pluripotent cells have promise in regenerative medicine. However, since generation of these cells involves genetic manipulation, it also faces significant hurdles before clinical use. This review discusses spermatogonial stem cells (SSCs) as a potential alternative source of pluripotent cells for use in human regenerative medicine. AREAS COVERED IN THE REVIEW The potential of SSCs to give rise to a wide range of other cell types either directly, when recombined with instructive inducers, or indirectly, after being converted to ES-like cells. Current understanding of the differentiation potential of murine SSCs and recent progress in isolating and culturing human SSCs and demonstrating their properties is also discussed. WHAT THE READER WILL GAIN Insight into the plasticity of SSCs and the unique properties of these cells for regenerative applications, the limitations of SSCs for stem-cell-based therapy and the potential alternatives available. TAKE HOME MESSAGE If methodologies for isolation and conversion of adult human SSCs directly into other cell types can be effectively developed, SSCs could represent an important alternate source of pluripotent cells that can be used in human tissue repair and/or regeneration.
Collapse
Affiliation(s)
- Liz Simon
- University of Illinois at Urbana Champaign, Veterinary Biosciences, VMBSB, 2001, S. Lincoln Avenue, Urbana, IL 61802, USA
| | | | | |
Collapse
|
93
|
Abstract
Primordial germ cells (PGCs) are embryonic progenitors for the gametes. In the gastrulating mouse embryo, a small group of cells begin expressing a unique set of genes and so commit to the germline. Over the next 3-5 days, these PGCs migrate anteriorly and increase rapidly in number via mitotic division before colonizing the newly formed gonads. PGCs then express a different set of unique genes, their inherited epigenetic imprint is erased and an individual methylation imprint is established, and for female PGCs, the silent X chromosome is reactivated. At this point, germ cells (GCs) commit to either a female or male sexual lineage, denoted by meiosis entry and mitotic arrest, respectively. This developmental program is determined by cues emanating from the somatic environment.
Collapse
Affiliation(s)
- Katherine A Ewen
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | | |
Collapse
|
94
|
Mikedis MM, Downs KM. Collagen type IV and Perlecan exhibit dynamic localization in the Allantoic Core Domain, a putative stem cell niche in the murine allantois. Dev Dyn 2010; 238:3193-204. [PMID: 19924818 DOI: 10.1002/dvdy.22129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A body of evidence suggests that the murine allantois contains a stem cell niche, the Allantoic Core Domain (ACD), that may contribute to a variety of allantoic and embryonic cell types. Given that extracellular matrix (ECM) regulates cell fate and function in niches, the allantois was systematically examined for Collagen type IV (ColIV) and Perlecan, both of which are associated with stem cell proliferation and differentiation. Not only was localization of ColIV and Perlecan more widespread during gastrulation than previously reported, but protein localization profiles were particularly robust and dynamic within the allantois and associated visceral endoderm as the ACD formed and matured. We propose that these data provide further evidence that the ACD is a stem cell niche whose activity is synchronized with associated visceral endoderm, possibly via ECM proteins.
Collapse
Affiliation(s)
- Maria M Mikedis
- Department of Anatomy, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | | |
Collapse
|
95
|
Wainwright EN, Wilhelm D. The game plan: cellular and molecular mechanisms of mammalian testis development. Curr Top Dev Biol 2010; 90:231-62. [PMID: 20691851 DOI: 10.1016/s0070-2153(10)90006-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
In mammals, biological differences between males and females, which influence many aspects of their physical, social, and psychological environments, are solely determined genetically. In the presence of a Y chromosome, the gonadal primordium will differentiate into a testis, whereas in the absence of the Y chromosome an ovary will develop. Testis and ovary subsequently direct the differentiation of all secondary sex characteristics down the male and female pathway, respectively. The male-determining factor on the Y chromosome, SRY, was identified some 20 years ago. Since then, significant progress has been made toward understanding the molecular and cellular pathways that result in the formation of a testis. Here, we review what is known about testis differentiation in mice and humans, with reference to other species where appropriate.
Collapse
Affiliation(s)
- Elanor N Wainwright
- Division of Molecular Genetics and Development, Institute for Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | | |
Collapse
|
96
|
Linher K, Dyce P, Li J. Primordial germ cell-like cells differentiated in vitro from skin-derived stem cells. PLoS One 2009; 4:e8263. [PMID: 20011593 PMCID: PMC2788220 DOI: 10.1371/journal.pone.0008263] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 11/19/2009] [Indexed: 01/19/2023] Open
Abstract
Background We have previously demonstrated that stem cells isolated from fetal porcine skin have the potential to form oocyte-like cells (OLCs) in vitro. However, primordial germ cells (PGCs), which must also be specified during the stem cell differentiation to give rise to these putative oocytes at more advanced stages of culture, were not systematically characterized. The current study tested the hypothesis that a morphologically distinct population of cells derived from skin stem cells prior to OLC formation corresponds to putative PGCs, which differentiate further into more mature gametes. Methodology/Principal Findings When induced to differentiate in an appropriate microenvironment, a subpopulation of morphologically distinct cells, some of which are alkaline phosphatase (AP)-positive, also express Oct4, Fragilis, Stella, Dazl, and Vasa, which are markers indicative of germ cell formation. A known differentially methylated region (DMR) within the H19 gene locus, which is demethylated in oocytes after establishment of the maternal imprint, is hypomethylated in PGC-like cells compared to undifferentiated skin-derived stem cells, suggesting that the putative germ cell population undergoes imprint erasure. Additional evidence supporting the germ cell identity of in vitro-generated PGC-like cells is that, when labeled with a Dazl-GFP reporter, these cells further differentiate into GFP-positive OLCs. Significance The ability to generate germ cell precursors from somatic stem cells may provide an in vitro model to study some of the unanswered questions surrounding early germ cell formation.
Collapse
Affiliation(s)
- Katja Linher
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
| | - Paul Dyce
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
| | - Julang Li
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
- * E-mail:
| |
Collapse
|
97
|
Abstract
Two major functions of the mammalian ovary are the production of germ cells (oocytes), which allow continuation of the species, and the generation of bioactive molecules, primarily steroids (mainly estrogens and progestins) and peptide growth factors, which are critical for ovarian function, regulation of the hypothalamic-pituitary-ovarian axis, and development of secondary sex characteristics. The female germline is created during embryogenesis when the precursors of primordial germ cells differentiate from somatic lineages of the embryo and take a unique route to reach the urogenital ridge. This undifferentiated gonad will differentiate along a female pathway, and the newly formed oocytes will proliferate and subsequently enter meiosis. At this point, the oocyte has two alternative fates: die, a common destiny of millions of oocytes, or be fertilized, a fate of at most approximately 100 oocytes, depending on the species. At every step from germline development and ovary formation to oogenesis and ovarian development and differentiation, there are coordinated interactions of hundreds of proteins and small RNAs. These studies have helped reproductive biologists to understand not only the normal functioning of the ovary but also the pathophysiology and genetics of diseases such as infertility and ovarian cancer. Over the last two decades, parallel progress has been made in the assisted reproductive technology clinic including better hormonal preparations, prenatal genetic testing, and optimal oocyte and embryo analysis and cryopreservation. Clearly, we have learned much about the mammalian ovary and manipulating its most important cargo, the oocyte, since the birth of Louise Brown over 30 yr ago.
Collapse
Affiliation(s)
- Mark A Edson
- Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | | | | |
Collapse
|
98
|
Weber S, Eckert D, Nettersheim D, Gillis AJM, Schäfer S, Kuckenberg P, Ehlermann J, Werling U, Biermann K, Looijenga LHJ, Schorle H. Critical function of AP-2 gamma/TCFAP2C in mouse embryonic germ cell maintenance. Biol Reprod 2009; 82:214-23. [PMID: 19776388 DOI: 10.1095/biolreprod.109.078717] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Formation of the germ cell lineage involves multiple processes, including repression of somatic differentiation and reacquisition of pluripotency as well as a unique epigenetic constitution. The transcriptional regulator Prdm1 has been identified as a main coordinator of this process, controlling epigenetic modification and gene expression. Here we report on the expression pattern of the transcription factor Tcfap2c, a putative downstream target of Prdm1, during normal mouse embryogenesis and the consequences of its specific loss in primordial germ cells (PGCs) and their derivatives. Tcfap2c is expressed in PGCs from Embryonic Day 7.25 (E 7.25) up to E 12.5, and targeted disruption resulted in sterile animals, both male and female. In the mutant animals, PGCs were specified but were lost around E 8.0. PGCs generated in vitro from embryonic stem cells lacking TCFAP2C displayed induction of Prdm1 and Dppa3. Upregulation of Hoxa1, Hoxb1, and T together with lack of expression of germ cell markers such Nanos3, Dazl, and Mutyh suggested that the somatic gene program is induced in TCFAP2C-deficient PGCs. Repression of TCFAP2C in TCam-2, a human PGC-resembling seminoma cell line, resulted in specific upregulation of HOXA1, HOXB1, MYOD1, and HAND1, indicative of mesodermal differentiation. Expression of genes indicative of ectodermal, endodermal, or extraembryonic differentiation, as well as the finding of no change to epigenetic modifications, suggested control by other factors. Our results implicate Tcfap2c as an important effector of Prdm1 activity that is required for PGC maintenance, most likely mediating Prdm1-induced suppression of mesodermal differentiation.
Collapse
Affiliation(s)
- Susanne Weber
- Institute of Pathology, Department of Developmental Pathology, University of Bonn, Bonn, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
99
|
Downs KM. The enigmatic primitive streak: prevailing notions and challenges concerning the body axis of mammals. Bioessays 2009; 31:892-902. [PMID: 19609969 PMCID: PMC2949267 DOI: 10.1002/bies.200900038] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The primitive streak establishes the antero-posterior body axis in all amniote species. It is thought to be the conduit through which mesoderm and endoderm progenitors ingress and migrate to their ultimate destinations. Despite its importance, the streak remains poorly defined and one of the most enigmatic structures of the animal kingdom. In particular, the posterior end of the primitive streak has not been satisfactorily identified in any species. Unexpectedly, and contrary to prevailing notions, recent evidence suggests that the murine posterior primitive streak extends beyond the embryo proper. In its extraembryonic site, the streak creates a node-like cell reservoir from which the allantois, a universal caudal appendage of all amniotes and the future umbilical cord of placental mammals, emerges. This new insight into the fetal/umbilical relationship may explain the etiology of a large number of umbilical-associated birth defects, many of which are correlated with abnormalities of the embryonic midline.
Collapse
Affiliation(s)
- Karen M Downs
- Department of Anatomy, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
| |
Collapse
|
100
|
Abstract
Background information. Primordial germ cells in developing male and female gonads are responsive to somatic cell cues that direct their sex-specific differentiation into functional gametes. The first divergence of the male and female pathways is a change in cell cycle state observed from 12.5 dpc (days post coitum) in mice. At this time XY and XX germ cells cease mitotic division and enter G1/G0 arrest and meiosis prophase I respectively. Aberrant cell cycle regulation at this time can lead to disrupted ovarian development, germ cell apoptosis, reduced fertility and/or the formation of germ cell tumours. Results. In order to unravel the mechanisms utilized by germ cells to achieve and maintain the correct cell cycle states, we analysed the expression of a large number of cell cycle genes in purified germ cells across the crucial time of sex differentiation. Our results revealed common signalling for both XX and XY germ cell survival involving calcium signalling. A robust mechanism for apoptosis and checkpoint control was observed in XY germ cells, characterized by p53 and Atm (ataxia telangiectasia mutated) expression. Additionally, a member of the retinoblastoma family and p21 were identified, linking these factors to XY germ cell G1/G0 arrest. Lastly, in XX germ cells we observed a down-regulation of genes involved in both G1- and G2-phases of the cell cycle consistent with their entry into meiosis. Conclusion. The present study has provided a detailed analysis of cell cycle gene expression during fetal germ cell development and identified candidate factors warranting further investigation in order to understand cases of aberrant cell cycle control in these specialized cells.
Collapse
|