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Ou HL, Kim CS, Uszkoreit S, Wickström SA, Schumacher B. Somatic Niche Cells Regulate the CEP-1/p53-Mediated DNA Damage Response in Primordial Germ Cells. Dev Cell 2020; 50:167-183.e8. [PMID: 31336098 DOI: 10.1016/j.devcel.2019.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/13/2019] [Accepted: 06/17/2019] [Indexed: 12/26/2022]
Abstract
Genome integrity in primordial germ cells (PGCs) is a prerequisite for fertility and species maintenance. In C. elegans, PGCs require global-genome nucleotide excision repair (GG-NER) to remove UV-induced DNA lesions. Failure to remove the lesions leads to the activation of the C. elegans p53, CEP-1, resulting in mitotic arrest of the PGCs. We show that the eIF4E2 translation initiation factor IFE-4 in somatic gonad precursor (SGP) niche cells regulates the CEP-1/p53-mediated DNA damage response (DDR) in PGCs. We determine that the IFE-4 translation target EGL-15/FGFR regulates the non-cell-autonomous DDR that is mediated via FGF-like signaling. Using hair follicle stem cells as a paradigm, we demonstrate that the eIF4E2-mediated niche cell regulation of the p53 response in stem cells is highly conserved in mammals. We thus reveal that the somatic niche regulates the CEP-1/p53-mediated DNA damage checkpoint in PGCs. Our data suggest that the somatic niche impacts the stability of heritable genomes.
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Affiliation(s)
- Hui-Ling Ou
- Institute for Genome Stability in Ageing and Disease, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Christine S Kim
- Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Paul Gerson Unna Group "Skin Homeostasis and Ageing," Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, D-50931 Cologne, Germany
| | - Simon Uszkoreit
- Institute for Genome Stability in Ageing and Disease, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Sara A Wickström
- Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Paul Gerson Unna Group "Skin Homeostasis and Ageing," Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, D-50931 Cologne, Germany; Helsinki Institute of Life Science, Biomedicum Helsinki, University of Helsinki, FI-00014 Helsinki, Finland; Wihuri Research Institute, Biomedicum Helsinki, University of Helsinki, FI-00014 Helsinki, Finland
| | - Björn Schumacher
- Institute for Genome Stability in Ageing and Disease, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.
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2
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Ulu F, Kim SM, Yokoyama T, Yamazaki Y. Dose-dependent functions of fibroblast growth factor 9 regulate the fate of murine XY primordial germ cells. Biol Reprod 2017; 96:122-133. [PMID: 28395336 PMCID: PMC5803787 DOI: 10.1095/biolreprod.116.143941] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/30/2016] [Indexed: 11/17/2022] Open
Abstract
Male differentiation of primordial germ cells (PGCs) is initiated by the inhibition of entry into meiosis and exposure to male-inducing factor(s), which are regulated by somatic elements of the developing gonad. Fibroblast growth factor 9 (FGF9) produced by pre-Sertoli cells is essential for male gonadal differentiation and also contributes to survival and male differentiation of XY PGCs. However, it is not clear how FGF9 regulates PGC fate. Using a PGC culture system, we identified dose-dependent, fate-determining functions of FGF9 in XY PGCs. Treatment with low levels of FGF9 (0.2 ng/ml) increased expression of male-specific Dnmt3L and Nanos2 in XY PGCs. Conversely, treatment with high levels of FGF9 (25 ng/ml) suppressed male-specific gene expression and stimulated proliferation of XY PGCs. Western blotting showed that low FGF9 treatment enhanced p38 MAPK (mitogen-activated protein kinase) phosphorylation in the same cells. In contrast, high FGF9 treatment significantly stimulated the ERK (extracellular signal-regulated kinase)1/2 signaling pathway in XY PGCs. We investigated the relationship between the ERK1/2 signaling pathway stimulated by high FGF9 and regulation of PGC proliferation. An ERK1/2 inhibitor (U0126) suppressed the PGC proliferation that would otherwise be stimulated by high FGF9 treatment, and increased Nanos2 expression in XY PGCs. Conversely, a p38 MAPK inhibitor (SB202190) significantly suppressed Nanos2 expression that would otherwise be stimulated by low FGF9 in XY PGCs. Taken together, our results suggest that stage-specific expression of FGF9 in XY gonads regulates the balance between proliferation and differentiation of XY PGCs in a dose-dependent manner.
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Affiliation(s)
- Ferhat Ulu
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Sung-Min Kim
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Toshifumi Yokoyama
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.,Department of Animal Science, Kobe University, Kobe, Hyogo, Japan
| | - Yukiko Yamazaki
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
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3
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Wang M, Zhang C, Huang C, Cheng S, He N, Wang Y, Ahmed MF, Zhao R, Jin J, Zuo Q, Zhang Y, Li B. Regulation of fibroblast growth factor 8 (FGF8) in chicken embryonic stem cells differentiation into spermatogonial stem cells. J Cell Biochem 2017; 119:2396-2407. [PMID: 28898437 DOI: 10.1002/jcb.26402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 08/30/2017] [Indexed: 01/15/2023]
Abstract
Fibroblast growth factors (FGFs) are essential in regulating the formation of spermatogonial stem cells (SSCs). Here, we explored the effect of FGF8 on chicken SSCs formation by knockdown or overexpression of FGF8 in chicken embryonic stem cells (ESCs) both in vitro and in vivo. Our results showed that knockdown of FGF8 could facilitate the differentiation of ESCs into SSCs, overexpression of FGF8 could promote PGCs self-renewal, inhibit SSCs formation. This study further revealed the positive correlation between the expression level of FGF8 and MAPK/ERK signal. In the absence of FGF8, the expression of downstream genes such as FGFR2, GRB2, RAS, BRAF, RAF1, and MEK2 was not maintained, while overexpressing FGF8 enhances them. Thus, our study demonstrated that FGF8 can regulate germ cell fate by modulating the dynamic equilibrium between differentiation and self-renewal, which provides a new idea for the study of germ cell regulatory network.
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Affiliation(s)
- Man Wang
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Chen Zhang
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Chuanli Huang
- Department of Life Sciences, Imperial College London, London, UK
| | - Shaoze Cheng
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Nana He
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Yilin Wang
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Mahmoud F Ahmed
- College of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Ruifeng Zhao
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Jing Jin
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Qisheng Zuo
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Yani Zhang
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
| | - Bichun Li
- Key Laboratory of Animal Breeding Reproduction and Molecular Design for Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou, P.R. China
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4
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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.
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Affiliation(s)
- Simon P Windley
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Vic., Australia
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Physiologic Course of Female Reproductive Function: A Molecular Look into the Prologue of Life. J Pregnancy 2015; 2015:715735. [PMID: 26697222 PMCID: PMC4678088 DOI: 10.1155/2015/715735] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/29/2015] [Indexed: 12/27/2022] Open
Abstract
The genetic, endocrine, and metabolic mechanisms underlying female reproduction are numerous and sophisticated, displaying complex functional evolution throughout a woman's lifetime. This vital course may be systematized in three subsequent stages: prenatal development of ovaries and germ cells up until in utero arrest of follicular growth and the ensuing interim suspension of gonadal function; onset of reproductive maturity through puberty, with reinitiation of both gonadal and adrenal activity; and adult functionality of the ovarian cycle which permits ovulation, a key event in female fertility, and dictates concurrent modifications in the endometrium and other ovarian hormone-sensitive tissues. Indeed, the ultimate goal of this physiologic progression is to achieve ovulation and offer an adequate environment for the installation of gestation, the consummation of female fertility. Strict regulation of these processes is important, as disruptions at any point in this evolution may equate a myriad of endocrine-metabolic disturbances for women and adverse consequences on offspring both during pregnancy and postpartum. This review offers a summary of pivotal aspects concerning the physiologic course of female reproductive function.
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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.
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Affiliation(s)
- Cassy M Spiller
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
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7
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Ewen K, Jackson A, Wilhelm D, Koopman P. A Male-Specific Role for p38 Mitogen-Activated Protein Kinase in Germ Cell Sex Differentiation in Mice1. Biol Reprod 2010; 83:1005-14. [DOI: 10.1095/biolreprod.110.086801] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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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.
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Affiliation(s)
- Katherine A Ewen
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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Wen J, Liu J, Song G, Liu L, Tang B, Li Z. Effects of 6-bromoindirubin-3′-oxime on the maintenance of pluripotency of porcine embryonic germ cells in combination with stem cell factor, leukemia inhibitory factor and fibroblast growth factor. Reproduction 2010; 139:1039-46. [DOI: 10.1530/rep-09-0539] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
6-Bromoindirubin-3′-oxime (BIO), which is one of the glycogen synthase kinase 3 inhibitors and a key regulator of numerous signaling pathways, was reported to be capable of maintaining the pluripotency of human and mouse embryonic stem cells. Presently, it is unknown whether BIO can influence the derivation of porcine embryonic germ (EG) cells. In this study, porcine primordial germ cells (PGCs) were isolated from gonads of 24- and 28-day embryos, and were then treated with BIO either individually or in combination with other cytokines (stem cell factor (SCF), leukemia inhibitory factor (LIF), and fibroblast growth factor (FGF); abbreviated as ‘3F’), and the effects of the treatment on the proliferation ability of porcine PGCs at early stage were examined using 5-bromo-2-deoxyuridine (Brdu) immunostaining assay. After continuous culture, the effects on the efficiency of porcine undifferentiated EG cells in the third passage and differentiated EG cells from embryoid bodies were examined as well. The results obtained through the observation of the Brdu-labeled PGCs indicated that BIO in combination with 3F resulted in a significant increase in the mitosis index, and also indicated that the BIO in combination with 3F had a higher efficiency in promoting the formation of porcine EG colony derived from porcine day 24 PGCs than BIO used either individually or in combination with LIF. In addition, BIO in combination with 3F exhibited the apparent anti-differentiation activity by reversing the differentiated EG cells to the undifferentiated status. Our results demonstrate that BIO in combination with SCF, LIF, and FGF could significantly contribute to the establishment of a porcine EG cell colony and maintain the undifferentiated status.
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10
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Sonne SB, Kristensen DM, Novotny GW, Olesen IA, Nielsen JE, Skakkebæk NE, Rajpert-De Meyts E, Leffers H. Testicular dysgenesis syndrome and the origin of carcinoma in situ testis. ACTA ACUST UNITED AC 2008; 31:275-87. [DOI: 10.1111/j.1365-2605.2007.00855.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Islam MQ, Islam K, Sharp CA. Epigenetic reprogramming of nonreplicating somatic cells for long-term proliferation by temporary cell-cell contact. Stem Cells Dev 2007; 16:253-68. [PMID: 17521237 DOI: 10.1089/scd.2006.0094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Embryonic stem (ES) cells are potential sources of tissue regeneration; however, transplanted ES cells produce tumors in the host tissues. In addition, transplantation between genetically unrelated individuals often results in graft rejection. Although the development of patient specific stem cell lines by somatic cell nuclear transfer (SCNT) represents a means of overcoming the problem of rejection, its human application has ethical dilemmas. Adult stem (AS) cells can also differentiate into specialized cells and may provide an alternative source of cells for human applications. In common with other somatic cells, AS cells have limited capacity for proliferation and cannot be produced in large quantities without genetic manipulation. We demonstrate here that nonreplicating mammalian cells can be reprogrammed for long-term proliferation by temporary cell-cell contact through coculture of AS cells with the GM05267-derived F7 mouse cell line. Subsequent elimination of F7 cells from the co-culture allows proliferation of previously nonreplicating cells, colonies of which can be isolated to produce cell lines. We also demonstrate that the epigenetically reprogrammed AS cells, without the physical transfer of either nuclear or cytoplasmic material from other cells, are capable of long-term proliferation and able to relay signals to other nonreplicating cells to reinitiate proliferation with no addition of recombinant factors. The reported cell amplification procedure is methodologically simple and can be easily reproduced. This procedure allows the production of an unlimited number of cells from a limited number of AS cells, making them an ideal source of cells for applications involving autologous cell transplantation.
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Affiliation(s)
- M Q Islam
- Laboratory of Cancer Genetics, Laboratory Medicine Center (LMC), University Hospital Linköping, 58216 Linköping, Sweden.
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12
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Lu M, Glover CH, Tien AH, Humphries RK, Piret JM, Helgason CD. Involvement of tyrosine kinase signaling in maintaining murine embryonic stem cell functionality. Exp Hematol 2007; 35:1293-302. [PMID: 17562354 DOI: 10.1016/j.exphem.2007.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 04/13/2007] [Accepted: 04/16/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We previously demonstrated that c-kit expression decreases during murine embryonic stem cell (ESC) differentiation induced by leukemia inhibitory factor removal. In this study, we addressed the possibility that c-kit is a marker of undifferentiated murine ESC and, moreover, that it plays a role in maintaining the undifferentiated state of these cells. MATERIALS AND METHODS c-kit expression was analyzed under various differentiation conditions by flow cytometry and quantitative reverse transcription polymerase chain reaction. ESC were then sorted on the basis of c-kit expression and functionality was investigated using embryoid body and colony-forming cell assays. Imatinib (Gleevec) and ACK2 were used to block, and stem cell factor was used to stimulate, c-kit activity. RESULTS c-kit expression decreased in two murine ESC lines under various differentiation conditions. Sorting of ESC populations on the basis of c-kit expression revealed significant differences in the functional capacities and gene expression profiles of the sorted populations. The inhibition studies revealed an important role for tyrosine kinase activity in maintaining ESC viability and differentiation capacity, at least in part by preventing apoptosis and enhancing cell cycle progression. However, activation of c-kit alone is not sufficient for maintaining undifferentiated ESC. CONCLUSION The results suggest that c-kit may represent a useful marker for monitoring ESC functionality. Moreover, tyrosine kinase signaling plays an important role in maintaining undifferentiated ESC. This work provides valuable insights into the complex signaling pathways that synergize to maintain the undifferentiated state of murine ESC.
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Affiliation(s)
- Min Lu
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, BC, Canada
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Lensch MW, Daheron L, Schlaeger TM. Pluripotent stem cells and their niches. ACTA ACUST UNITED AC 2006; 2:185-201. [PMID: 17625255 DOI: 10.1007/s12015-006-0047-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 02/04/2023]
Abstract
The ability of stem cells to self-renew and to replace mature cells is fundamental to ontogeny and tissue regeneration. Stem cells of the adult organism can be categorized as mono-, bi-, or multipotent, based on the number of mature cell types to which they can give rise. In contrast, pluripotent stem cells of the early embryo have the ability to form every cell type of the adult body. Permanent lines of pluripotent stem cells have been derived from preimplantation embryos (embryonic stem cells), fetal primordial germ cells (embryonic germ cells), and malignant teratocarcinomas (embryonal carcinoma cells). Cultured pluripotent stem cells can easily be manipulated genetically, and they can be matured into adult-type stem cells and terminally differentiated cell types in vitro, thereby, providing powerful model systems for the study of mammalian embryogenesis and disease processes. In addition, human embryonic stem cell lines hold great promise for the development of novel regenerative therapies. To fully utilize the potential of these cells, we must first understand the mechanisms that control pluripotent stem cell fate and function. In recent decades, the microenvironment or niche has emerged as particularly critical for stem cell regulation. In this article, we review how pluripotent stem cell signal transduction mechanisms and transcription factor circuitries integrate information provided by the microenvironment. In addition, we consider the potential existence and location of adult pluripotent stem cell niches, based on the notion that a revealing feature indicating the presence of stem cells in a given tissue is the occurrence of tumors whose characteristics reflect the normal developmental potential of the cognate stem cells.
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Affiliation(s)
- M William Lensch
- Division of Hematology/Oncology, Children's Hospital Boston, Boston, MA 02115, USA
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Durcova-Hills G, Adams IR, Barton SC, Surani MA, McLaren A. The role of exogenous fibroblast growth factor-2 on the reprogramming of primordial germ cells into pluripotent stem cells. Stem Cells 2006; 24:1441-9. [PMID: 16769760 DOI: 10.1634/stemcells.2005-0424] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The germ cell lineage is a specified cell population that passes through a series of differentiation steps before giving rise, eventually, to either eggs or sperm. We have investigated the manner in which primordial germ cells (PGCs) are reprogrammed in vitro to form pluripotent stem cells in response to exogenous fibroblast growth factor-2 (FGF-2). The response is dependent on time of exposure and concentration of FGF-2. PGCs isolated in culture show a motile phenotype and lose any expression of a characteristic germ cell marker, mouse vasa homolog. Subsequently, some but not all of the cells show further changes of phenotype, accompanied by changes in expression of endogenous FGF-2 and up-regulation of its receptor, fibroblast growth factor receptor-3, in the nucleus. We propose that it is from this reprogrammed component of the now heterogeneous PGC population that pluripotent stem cells arise.
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MESH Headings
- Animals
- Cell Differentiation/drug effects
- Cells, Cultured
- Colony-Forming Units Assay
- Female
- Fibroblast Growth Factor 2/metabolism
- Fibroblast Growth Factor 2/pharmacology
- Germ Cells/cytology
- Germ Cells/drug effects
- Germ Cells/metabolism
- In Vitro Techniques
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Pluripotent Stem Cells/cytology
- Pluripotent Stem Cells/drug effects
- Pluripotent Stem Cells/metabolism
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Signal Transduction
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Affiliation(s)
- Gabriela Durcova-Hills
- The Wellcome Trust/Cancer United Kingdom Gurdon Institute of Cancer and Developmental Biology, Cambridge
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15
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Francis RJB, Lo CW. Primordial germ cell deficiency in the connexin 43 knockout mouse arises from apoptosis associated with abnormal p53 activation. Development 2006; 133:3451-60. [PMID: 16887824 DOI: 10.1242/dev.02506] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Connexin 43 knockout (Cx43alpha1KO) mice exhibit germ cell deficiency, but the underlying cause for the germ cell defect was unknown. Using an Oct4-GFP reporter transgene, we tracked the distribution and migration of primordial germ cells (PGCs) in the Cx43alpha1KO mouse embryo. Analysis with dye injections showed PGCs are gap-junction-communication competent, with dye coupling being markedly reduced in Cx43alpha1-deficient PGCs. Time-lapse videomicroscopy and motion analysis showed that the directionality and speed of cell motility were reduced in the Cx43alpha1KO PGCs. This was observed both in E8.5 and E11.5 embryos. By contrast, PGC abundance did not differ between wild-type and heterozygous/homozygous Cx43alpha1KO embryos until E11.5, when a marked reduction in PGC abundance was detected in the homozygous Cx43alpha1KO embryos. This was accompanied by increased PGC apoptosis and increased expression of activated p53. Injection of alpha-pifithrin, a p53 antagonist, inhibited PGC apoptosis and prevented the loss of PGC. Analysis using a cell adhesion assay indicated a reduction in beta1-integrin function in the Cx43alpha1KO PGCs. Together with the abnormal activation of p53, these findings suggest the possibility of anoikis-mediated apoptosis. Overall, these findings show Cx43alpha1 is essential for PGC survival, with abnormal p53 activation playing a crucial role in the apoptotic loss of PGCs in the Cx43alpha1KO mouse embryos.
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Affiliation(s)
- Richard J B Francis
- Laboratory of Developmental Biology, National Heart Lung and Blood Institute, National Institutes of Health, Building 50/Room 4537, 9000 Rockville Pike, Bethesda, MD 20892, USA
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16
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Takeuchi Y, Molyneaux K, Runyan C, Schaible K, Wylie C. The roles of FGF signaling in germ cell migration in the mouse. Development 2005; 132:5399-409. [PMID: 16291796 DOI: 10.1242/dev.02080] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fibroblast growth factor (FGF) signaling is thought to play a role in germ cell behavior. FGF2 has been reported to be a mitogen for primordial germ cells in vitro, whilst combinations of FGF2, steel factor and LIF cause cultured germ cells to transform into permanent lines of pluripotent cells resembling ES cells. However, the actual function of FGF signaling on the migrating germ cells in vivo is unknown. We show, by RT-PCR analysis of cDNA from purified E10.5 germ cells, that germ cells express two FGF receptors: Fgfr1-IIIc and Fgfr2-IIIb. Second, we show that FGF-mediated activation of the MAP kinase pathway occurs in germ cells during their migration, and thus they are potentially direct targets of FGF signaling. Third, we use cultured embryo slices in simple gain-of-function experiments,using FGF ligands, to show that FGF2, a ligand for FGFR1-IIIc, affects motility, whereas FGF7, a ligand for FGFR2-IIIb, affects germ cell numbers. Loss of function, using a specific inhibitor of FGF signaling, causes increased apoptosis and inhibition of cell shape change in the migrating germ cells. Lastly, we confirm in vivo the effects seen in slice cultures in vitro,by examining germ cell positions and numbers in embryos carrying a loss-of-function allele of FGFR2-IIIb. In FGFR2-IIIb-/- embryos,germ cell migration is unaffected, but the numbers of germ cells are significantly reduced. These data show that a major role of FGF signaling through FGFR2-IIIb is to control germ cell numbers. The data do not discriminate between direct and indirect effects of FGF signaling on germ cells, and both may be involved.
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MESH Headings
- Alternative Splicing
- Animals
- Cell Count
- Cell Movement/physiology
- Embryo, Mammalian/cytology
- Extracellular Signal-Regulated MAP Kinases/physiology
- Female
- Fibroblast Growth Factor 2/physiology
- Fibroblast Growth Factor 7/physiology
- Germ Cells/cytology
- Germ Cells/physiology
- In Vitro Techniques
- Male
- Mice
- Mice, Transgenic
- Mutation
- Pyrroles/pharmacology
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/metabolism
- Signal Transduction
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Affiliation(s)
- Yutaka Takeuchi
- Department of Marine Biosciences, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
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17
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Han BK, Kim JN, Shin JH, Kim JK, Jo DH, Kim H, Han JY. Proteome analysis of chicken embryonic gonads: identification of major proteins from cultured gonadal primordial germ cells. Mol Reprod Dev 2005; 72:521-9. [PMID: 16161032 DOI: 10.1002/mrd.20374] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The domestic chicken (Gallus gallus) is an important model for research in developmental biology because its embryonic development occurs in ovo. To examine the mechanism of embryonic germ cell development, we constructed proteome map of gonadal primordial germ cells (gPGCs) from chicken embryonic gonads. Embryonic gonads were collected from 500 embryos at 6 days of incubation, and the gPGCs were cultured in vitro until colony formed. After 7-10 days in culture, gPGC colonies were separated from gonadal stroma cells (GSCs). Soluble extracts of cultured gPGCs were then fractionated by two-dimensional gel electrophoresis (pH 4-7). A number of protein spots, including those that displayed significant expression levels, were then identified by use of matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and LC-MS/MS. Of the 89 gPGC spots examined, 50 yielded mass spectra that matched avian proteins found in on-line databases. Proteome map of this type will serve as an important reference for germ cell biology and transgenic research.
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Affiliation(s)
- Beom Ku Han
- Avicore Biotechnology Institute Inc., Hanlim Human Tower, Gunpo City, Gyeonggi-Do, Korea
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18
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Høyer PE, Byskov AG, Møllgård K. Stem cell factor and c-Kit in human primordial germ cells and fetal ovaries. Mol Cell Endocrinol 2005; 234:1-10. [PMID: 15836947 DOI: 10.1016/j.mce.2004.09.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 09/10/2004] [Indexed: 11/16/2022]
Abstract
The distribution of the tyrosine kinase receptor c-Kit and its ligand stem cell factor (SCF) was evaluated by immunohistochemistry in primordial germ cells (PGCs) and human embryonic gonads during weeks 5-8 of prenatal life, and fetal ovaries during weeks 9-36 of prenatal life. Distinct c-Kit and SCF staining was present in primordial germ cells in the wall of the hindgut and in the dorsal mesentery, particularly on level with the 10th thoracic columnar segment. Several PGCs were in close contact with c-Kit-negative but SCF-positive autonomic nerve fibers of the dorsal mesentery. Many fibroblasts and mesothelial cells of the dorsal mesentery were clearly stained for SCF, but not for c-Kit. Prominent c-Kit and SCF staining was present in germ cells of the embryonic gonadal anlage and in oogonia during further ovarian development. However, oocytes were either unstained or faintly stained for SCF. Oocytes not yet enclosed in follicles or present in primordial follicles were either unstained or exhibited faint cytoplasmic c-Kit staining, whereas oocytes of growing preantral follicles again showed distinct cell membrane staining which decreased during further follicular growth. Theca cells did not stain for c-Kit. Some pregranulosa cells and the first formed granulosa cells of primordial follicles were c-Kit stained. Granulosa cells of other follicles were not c-Kit stained. In the inner part of the cortex, SCF immunolabeling was detected in some pregranulosa cells surrounding cords containing germ cells and involved in formation of primordial follicles. Granulosa cells of primordial and growing follicles, including medium-sized antral follicles also revealed SCF staining. In conclusion, this first report on SCF in human PGCs and embryonic and fetal ovaries together with the c-Kit data lend substantial countenance to the notion that c-Kit and SCF play important roles during ascent of primordial germ cells towards the gonadal anlage, and during oogenesis and folliculogenesis in the human fetal ovary. We suggest that both autocrine and paracrine mechanisms are involved in the proposed anti-apoptotic effect of the c-Kit/SCF duet while PGCs are present in the dorsal mesentery. The SCF-positive autonomic nerve fibers of the dorsal mesentery, mesothelial cells and fibroblasts may nurse and perhaps guide PGCs during their ascent.
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Affiliation(s)
- Poul Erik Høyer
- Institute of Medical Anatomy, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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19
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De Felici M, Klinger FG, Farini D, Scaldaferri ML, Iona S, Lobascio M. Establishment of oocyte population in the fetal ovary: primordial germ cell proliferation and oocyte programmed cell death. Reprod Biomed Online 2005; 10:182-91. [PMID: 15823221 DOI: 10.1016/s1472-6483(10)60939-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Strict control of cell proliferation and cell loss is essential for the coordinated functions of different cell populations in complex multicellular organisms. Oogenesis is characterized by a first phase occurring during embryo-fetal life and in common with spermatogenesis, during which mitotic proliferation of the germline stem cells, the primordial germ cells (PGC), prevails over germ cell death. The result is the formation of a relatively high number of germ cells depending on the species, ready to enter sex specific differentiation. In the female, PGC enter into meiosis and become oocytes, thereby ending their stem cell potential. After entering into meiosis in the fetal ovary, oocytes pass through leptotene, zygotene and pachytene stages before arresting in the last stage of meiotic prophase I, the diplotene or dictyate stage at about the time of birth. The most part of oocytes die during the fetal period or shortly after birth. It is widely accepted that in mammals a female is born with a fixed number of oocytes within the ovaries, which over the years progressively decreases without possibility for renewal. Once the oocyte reserve has been exhausted, ovarian senescence, driving what is referred to as the menopause in women, rapidly ensues. The fertile lifespan of a female depends by the size of the oocyte pool at birth and the rapidity of the oocyte pool depletion. Which mechanisms control PGC proliferation? Why do most of the oocytes die during fetal life and what are the mechanisms of such massive degeneration? Is it possible to prolong the lifespan of a female by reducing oocyte lost during the fetal life? This review reports some of the most recent results obtained in an attempt to answer these questions.
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Affiliation(s)
- Massimo De Felici
- Department of Public Health and Cell Biology, Section of Histology and Embryology, University of Rome Tor Vergata, Rome, Via Montpellier 1, 00173 Rome, Italy.
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20
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Abstract
Specification of primordial germ cells (PGCs) in the proximal epiblast enables about 45 founder PGCs clustered at the base of the allantoic bud to enter the embryo by active cell movement. Specification of the PGC lineage depends on paracrine signals derived from the somatic cell neighbors in the extraembryonic ectoderm. Secretory bone morphogenetic proteins (BMP) 4, BMP8b, and BMP2 and components of the Smad signaling pathway participate in the specification of PGCs. Cells in the extraembryonic ectoderm induce expression of the gene fragilis in the epiblast in the presence of BMP4, targeting competence of PGCs. The fragilis gene encodes a family of transmembrane proteins presumably involved in homotypic cell adhesion. As PGCs migrate throughout the hindgut, they express nanos3 protein. In the absence of nanos3 gene expression, no germ cells are detected in ovary and testis. During migration and upon arrival at the genital ridges, the population of PGCs is regulated by a balanced proliferation/programmed cell death or apoptosis. Paracrine and autocrine mechanisms, involving transforming growth factor-beta1 and fibroblast growth factors exert stimulatory or inhibitory effects on PGCs proliferation, modulated in part by the membrane-bound form of stem cell factor. Apoptosis requires the participation of the pro-apoptotic family member Bax, whose activity is balanced by the anti-apoptotic family member Bcl21/Bcl-x. In addition, a loss of cell-cell contacts in vitro results in the apoptotic elimination of PGCs. It needs to be determined whether apoptosis is triggered by a failure of PGC to establish and maintain appropriate cell-cell contacts with somatic cells or whether undefined survival factors released by adjacent somatic cells cannot reach physiological levels to satisfy needs of the expanding population of PGCs.
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Affiliation(s)
- Laura L Tres
- Department of Cell Biology and Anatomical Sciences, The Sophie Davis School of Biomedical Education, The City University of New York Medical School, New York, New York 10031, USA.
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