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Rouge M, Drouault M, Hanoux V, Delalande C, Bouraïma-Lelong H. Ex vivo effects of 17β-estradiol on the prepubertal rat testis. Reprod Toxicol 2023; 118:108363. [PMID: 36931579 DOI: 10.1016/j.reprotox.2023.108363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023]
Abstract
Although it is well established that testis produces estrogens, their precise effect is not fully documented, particularly during the prepubertal period. In a previous in vivo study, we demonstrated that an exposure of prepubertal rats (15-30 days post-partum (dpp)) to 17β-estradiol (E2) delays the establishment of spermatogenesis. In order to characterize the mechanisms of action and the direct targets of E2 on the immature testis, we developed an organotypic culture model of testicular explants obtained from prepubertal rats (15, 20 and 25 dpp). To determine the involvement of nuclear estrogen receptors (ERs) in the effect of E2, particularly that of ESR1 which is the major ER expressed in the prepubertal testis, a pre-treatment with the full antagonist of this type of ERs (ICI 182.780) was performed. Histological analyses, gene expression studies and hormonal assays were conducted to investigate the effects of E2 on steroidogenesis- and spermatogenesis-related endpoints. Testicular explants from 15 dpp rats were unresponsive to E2 exposure while E2 effects were observed in those obtained from 20 and 25 dpp rats. An E2 exposure of testicular explants obtained from 20 dpp rats seemed to accelerate the establishment of spermatogenesis, whereas an E2 exposure of 25 dpp testicular explants induced a delay of this process. These effects could be related to the E2-induced modulation of steroidogenesis, and involved both ESR1-dependent and -independent mechanisms of action. Overall, this ex vivo study demonstrated differential age- and concentration-related effects of E2 on the testis during the prepubertal period.
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Affiliation(s)
- Marion Rouge
- Normandie Univ, UNICAEN, OeReCa, 14000 Caen, France
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Zakharova L, Sharova V, Izvolskaia M. Mechanisms of Reciprocal Regulation of Gonadotropin-Releasing Hormone (GnRH)-Producing and Immune Systems: The Role of GnRH, Cytokines and Their Receptors in Early Ontogenesis in Normal and Pathological Conditions. Int J Mol Sci 2020; 22:ijms22010114. [PMID: 33374337 PMCID: PMC7795970 DOI: 10.3390/ijms22010114] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/15/2022] Open
Abstract
Different aspects of the reciprocal regulatory influence on the development of gonadotropin-releasing hormone (GnRH)-producing- and immune systems in the perinatal ontogenesis and their functioning in adults in normal and pathological conditions are discussed. The influence of GnRH on the development of the immune system, on the one hand, and the influence of proinflammatory cytokines on the development of the hypothalamic-pituitary-gonadal system, on the other hand, and their functioning in adult offspring are analyzed. We have focused on the effects of GnRH on the formation and functional activity of the thymus, as the central organ of the immune system, in the perinatal period. The main mechanisms of reciprocal regulation of these systems are discussed. The reproductive health of an individual is programmed by the establishment and development of physiological systems during critical periods. Regulatory epigenetic mechanisms of development are not strictly genetically controlled. These processes are characterized by a high sensitivity to various regulatory factors, which provides possible corrections for disorders.
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Gonadotropin-Releasing Hormone in Regulation of Thymic Development in Rats: Profile of Thymic Cytokines. Int J Mol Sci 2019; 20:ijms20164033. [PMID: 31430847 PMCID: PMC6720952 DOI: 10.3390/ijms20164033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/13/2019] [Accepted: 08/17/2019] [Indexed: 01/17/2023] Open
Abstract
An increasing body of recent experimental data confirms the impact of neurohormones on fetal development and function of different body systems. The synthesis of many neurohormones starts in fetal tissues before the hypothalamic–pituitary–adrenal and hypothalamic–pituitary–gonadal systems are formed, and their high levels are detected in the bloodstream. Here, we studied the role of gonadotropin-releasing hormone (GnRH) in rat thymus development and tried to reveal possible mechanisms underlying the GnRH effects in early development. Western blotting and reverse transcription-polymerase chain reaction allowed us to identify receptor for GnRH in the fetal thymus with peak expression on embryonic days 17–18 (ED17–18). Blocking the receptors in utero on ED17 by a GnRH antagonist suppressed the concanavalin A-induced proliferative response of T cells in adults. GnRH (10−7 M) increased mRNA expression of interleukin (IL)-4, IL-10, IL-1β, interferon γ (IFNγ), and tumor necrosis factor α (TNFα) in the thymus of 18-day fetuses after an ex vivo culture for 24 h. The increased mRNA levels of the cytokines in the thymus were accompanied by increased numbers of CD4+ T helpers. Overall, the data obtained confirm the regulatory or morphogenetic effect of GnRH on fetal thymus development mediated by synthesis of thymic cytokines.
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Ramírez-Reveco A, Villarroel-Espíndola F, Rodríguez-Gil JE, Concha II. Neuronal signaling repertoire in the mammalian sperm functionality. Biol Reprod 2017; 96:505-524. [PMID: 28339693 DOI: 10.1095/biolreprod.116.144154] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/24/2017] [Indexed: 12/14/2022] Open
Abstract
The common embryonic origin has been a recurrent explanation to understand the presence of "neural receptors" in sperm. However, this designation has conditioned a bias marked by the classical neurotransmission model, dismissing the possibility that neurotransmitters can play specific roles in the sperm function by themselves. For instance, the launching of acrosome reaction, a fundamental sperm function, includes several steps that recall the process of presynaptic secretion. Unlike of postsynaptic neuron, whose activation is mediated by molecular interaction between neurotransmitter and postsynaptic receptors, the oocyte activation is not mediated by receptors, but by cytosolic translocation of sperm phospholipase (PLCζ). Thus, the sperm has a cellular design to access and activate the oocyte and restore the ploidy of the species by an "allogenic pronuclear fusion." At subcellular level, the events controlling sperm function, particularly the capacitation process, are activated by chemical signals that trigger ion fluxes, sterol oxidation, synthesis of cyclic adenosine monophosphate, protein kinase A activation, tyrosine phosphorylations and calcium signaling, which correspond to second messengers similar to those associated with exocytosis and growth cone guidance in neurons. Classically, the sperm function associated with neural signals has been analyzed as a unidimensional approach (single ligand-receptor effect). However, the in vivo sperm are exposed to multidimensional signaling context, for example, the GABAergic, monoaminergic, purinergic, cholinergic, and melatoninergic, to name a few. The aim of this review is to present an overview of sperm functionality associated with "neuronal signaling" and possible cellular and molecular mechanisms involved in their regulation.
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Affiliation(s)
- Alfredo Ramírez-Reveco
- Instituto de Ciencia Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Franz Villarroel-Espíndola
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.,Department of Pathology and Pediatric Pathology, Yale University, New Haven, Connecticut, USA
| | - Joan E Rodríguez-Gil
- Unitat de Reproducció Animal, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Ilona I Concha
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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Rwigemera A, Joao F, Delbes G. Fetal testis organ culture reproduces the dynamics of epigenetic reprogramming in rat gonocytes. Epigenetics Chromatin 2017; 10:19. [PMID: 28413450 PMCID: PMC5387332 DOI: 10.1186/s13072-017-0127-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/05/2017] [Indexed: 12/16/2022] Open
Abstract
Background Epigenetic reprogramming is a critical step in male germ cell development that occurs during perinatal life. It is characterized by the remodeling of different epigenetic marks such as DNA methylation (5mC) and methylation of histone H3. It has been suggested that endocrine disruptors can affect the male germline epigenome by altering epigenetic reprogramming, but the mechanisms involved are still unknown. We have previously used an organ culture system that maintains the development of the different fetal testis cell types, to evaluate the effects of various endocrine disruptors on gametogenesis and steroidogenesis in the rat. We hypothesize that this culture model can reproduce the epigenetic reprogramming in gonocytes. Our aim was to establish the kinetics of three epigenetic marks throughout perinatal development in rats in vivo and compare them after different culture times. Results Using immunofluorescence, we showed that H3K4me2 transiently increased in gonocytes at 18.5 days post-coitum (dpc), while H3K4me3 displayed a stable increase in gonocytes from 18.5 dpc until after birth. 5mC progressively increased from 20.5 dpc until after birth. Using GFP-positive gonocytes purified from GCS-EGFP rats, we established the chronology of re-methylation of H19 and Snrpn in rat gonocytes. Most importantly, using testis explanted at 16.5 or 18.5 dpc and cultured for 2–4 days, we demonstrated that the kinetics of changes in H3K4me2, H3K4me3, global DNA methylation and on parental imprints can generally be reproduced ex vivo with the model of organ culture without the addition of serum. Conclusions This study reveals the chronology of three epigenetic marks (H3K4me2, H3K4me3 and 5mC) and the patterns of methylation of H19 and Snrpn differentially methylated regions in rat gonocytes during perinatal development. Most importantly, our results suggest that the organ culture can reproduce the process of epigenetic reprogramming and can be used to study the impact of environmental chemicals on the establishment of the male germ cell epigenome. Electronic supplementary material The online version of this article (doi:10.1186/s13072-017-0127-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Arlette Rwigemera
- Institut National de la Recherche Scientifique, Centre INRS - Institut Armand-Frappier, 531, boulevard des Prairies, Laval, QC H7V 1B7 Canada
| | - Fabien Joao
- Institut National de la Recherche Scientifique, Centre INRS - Institut Armand-Frappier, 531, boulevard des Prairies, Laval, QC H7V 1B7 Canada
| | - Geraldine Delbes
- Institut National de la Recherche Scientifique, Centre INRS - Institut Armand-Frappier, 531, boulevard des Prairies, Laval, QC H7V 1B7 Canada
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Wang Y, Bilandzic M, Ooi GT, Findlay JK, Stenvers KL. Endogenous inhibins regulate steroidogenesis in mouse TM3 Leydig cells by altering SMAD2 signalling. Mol Cell Endocrinol 2016; 436:68-77. [PMID: 27465829 DOI: 10.1016/j.mce.2016.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 12/28/2022]
Abstract
This study tested the hypothesis that inhibins act in an autocrine manner on Leydig cells using a pre-pubertal Leydig cell line, TM3, as a model of immature Leydig cells. The expression of Inha, Inhba, and Inhbb in TM3 cells was determined by RT-PCR and the production of the inhibin-alpha subunit was confirmed by western blot. Knockdown of Inha expression resulted in significant decreases in the expression of Leydig cell markers Cyp17a1, Cyp11a1, Nr5a1, and Insl3. Western blot showed that activin A, TGFβ1 and TGFβ2 activated SMAD2, and that knockdown of Inha expression in TM3 cells enhanced both activin A- and TGFβ-induced SMAD2 activation. SB431542, a chemical inhibitor of the TGFβ/activin type I receptors, blocked ligand-induced SMAD2 activation and the downregulation of Cyp17a1 expression. Our findings demonstrate that TGFβs and activin A negatively regulate steroidogenic gene expression in TM3 cells via ALK4/5 and SMAD2 and endogenous inhibins can counter this regulation.
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Affiliation(s)
- Yao Wang
- Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Victoria, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia.
| | - Maree Bilandzic
- Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Victoria, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia
| | - Guck T Ooi
- Sun BioMedical Technologies, 209 W. Ridgecrest Blvd, Suite A, Ridgecrest, CA, 93555, USA
| | - Jock K Findlay
- Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Victoria, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia
| | - Kaye L Stenvers
- Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Victoria, 3168, Australia; Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, 3168, Australia
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Li Y, Zhang M, Li S, Lv R, Chen P, Liu R, Liang G, Yin L. The Use of the Nematode Caenorhabditis elegans to Evaluate the Adverse Effects of Epoxiconazole Exposure on Spermatogenesis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:E993. [PMID: 27740608 PMCID: PMC5086732 DOI: 10.3390/ijerph13100993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/20/2016] [Accepted: 09/29/2016] [Indexed: 12/29/2022]
Abstract
There is increasing evidence that epoxiconazole exposure can affect reproductive function, but few studies have investigated adverse effects on spermatogenesis. The nematode Caenorhabditis elegans (C. elegans) was used in our study to assess effects of epoxiconazole on spermatogenesis in male nematodes after 48 h of exposure to concentrations of 0.1, 1.0, or 10.0 μg/L. The results demonstrated that epoxiconazole exposure affected spermatogenesis, decreasing the number of total germ cells, mitotic cells, meiotic cells and spermatids, spermatid diameter, and cross-sectional area, and inducing mitotic germ cell proliferation arrest, premature entry into meiosis, and sperm activation inhibition; however, sperm transfer showed no abnormal changes. In addition, the results showed that epoxiconazole activated the transforming growth factor-β (TGFβ) signaling pathway and increased the expression levels of gene daf-1, daf-3, daf-4, daf-5 and daf-7 in nematodes. We therefore propose that epoxiconazole acts by activating the TGFβ signaling pathway, leading to the impairment of spermatogenesis and the consequent decline in male fertility.
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Affiliation(s)
- Yunhui Li
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Minhui Zhang
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Shaojun Li
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | - Rongrong Lv
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | - Ran Liu
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Lihong Yin
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
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Abstract
The two major functions of the testis, steroidogenesis and gametogenesis, take place during fetal life. These two functions have been extensively studied in rodents and adult humans. However, their onset during fetal life is poorly documented in humans. In the first part of this work we presented both our experimental data and some data of literature concerning the development of the human fetal testis. In the second part of this article, using the organ culture system we previously developed, we have investigated the regulations or perturbations of fetal testis development both in rodent and human models. Our findings provide important insight into the potential role of exposure to environmental pollutants (physical factors, in particular ionizing radiation, cadmium and endocrine disruptors such as phthalates) during fetal testicular development and their potential deleterious effects on male fertility in adulthood. Our results highlight the specificity of the human model compared with rodent models.
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Manku G, Culty M. Mammalian gonocyte and spermatogonia differentiation: recent advances and remaining challenges. Reproduction 2015; 149:R139-57. [DOI: 10.1530/rep-14-0431] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The production of spermatozoa relies on a pool of spermatogonial stem cells (SSCs), formed in infancy from the differentiation of their precursor cells, the gonocytes. Throughout adult life, SSCs will either self-renew or differentiate, in order to maintain a stem cell reserve while providing cells to the spermatogenic cycle. By contrast, gonocytes represent a transient and finite phase of development leading to the formation of SSCs or spermatogonia of the first spermatogenic wave. Gonocyte development involves phases of quiescence, cell proliferation, migration, and differentiation. Spermatogonia, on the other hand, remain located at the basement membrane of the seminiferous tubules throughout their successive phases of proliferation and differentiation. Apoptosis is an integral part of both developmental phases, allowing for the removal of defective cells and the maintenance of proper germ–Sertoli cell ratios. While gonocytes and spermatogonia mitosis are regulated by distinct factors, they both undergo differentiation in response to retinoic acid. In contrast to postpubertal spermatogenesis, the early steps of germ cell development have only recently attracted attention, unveiling genes and pathways regulating SSC self-renewal and proliferation. Yet, less is known on the mechanisms regulating differentiation. The processes leading from gonocytes to spermatogonia have been seldom investigated. While the formation of abnormal gonocytes or SSCs could lead to infertility, defective gonocyte differentiation might be at the origin of testicular germ cell tumors. Thus, it is important to better understand the molecular mechanisms regulating these processes. This review summarizes and compares the present knowledge on the mechanisms regulating mammalian gonocyte and spermatogonial differentiation.
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Effects of vitamin A on in vitro maturation of pre-pubertal mouse spermatogonial stem cells. PLoS One 2013; 8:e82819. [PMID: 24349372 PMCID: PMC3857286 DOI: 10.1371/journal.pone.0082819] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 11/06/2013] [Indexed: 11/19/2022] Open
Abstract
Testicular tissue cryopreservation is the only potential option for fertility preservation in pre-pubertal boys exposed to gonadotoxic treatment. Completion of spermatogenesis after in vitro maturation is one of the future uses of harvested testicular tissue. The purpose of the current study was to evaluate the effects of vitamin A on in vitro maturation of fresh and frozen-thawed mouse pre-pubertal spermatogonial stem cells in an organ culture system. Pre-pubertal CD1 mouse fresh testes were cultured for 7 (D7), 9 (D9) and 11 (D11) days using an organ culture system. Basal medium was supplemented with different concentrations of retinol (Re) or retinoic acid (RA) alone or in combination. Seminiferous tubule morphology (tubule diameter, intra-tubular cell type), intra-tubular cell death and proliferation (PCNA antibody) and testosterone level were assessed at D7, D9 and D11. Pre-pubertal mouse testicular tissue were frozen after a soaking temperature performed at -7°C, -8°C or -9°C and after thawing, were cultured for 9 days, using the culture medium preserving the best fresh tissue functionality. Retinoic acid at 10-6M and retinol at 3.3.10-7M, as well as retinol 10-6M are favourable for seminiferous tubule growth, maintenance of intra-tubular cell proliferation and germ cell differentiation of fresh pre-pubertal mouse spermatogonia. Structural and functional integrity of frozen-thawed testicular tissue appeared to be well-preserved after soaking temperature at -8°C, after 9 days of organotypic culture using 10-6M retinol. RA and Re can control in vitro germ cell proliferation and differentiation. Re at a concentration of 10-6M maintains intra-tubular cell proliferation and the ability of spermatogonia to initiate spermatogenesis in fresh and frozen pre-pubertal mouse testicular tissue using a soaking temperature at -8°C. Our data suggested a possible human application for in vitro maturation of cryopreserved pre-pubertal testicular tissue.
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12
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Evaluation of immunohistochemical markers of germ cells’ proliferation in the developing rat testis: A comparative study. Tissue Cell 2008; 40:43-50. [DOI: 10.1016/j.tice.2007.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 08/30/2007] [Accepted: 09/06/2007] [Indexed: 11/24/2022]
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Lambrot R, Livera G, Coffigny H, Pairault C, Frydman R, Habert R, Rouiller-Fabre V. A new method for toxicity assays on human and mouse fetal testis. Biochimie 2006; 88:1831-5. [PMID: 17070978 DOI: 10.1016/j.biochi.2006.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 09/21/2006] [Indexed: 11/28/2022]
Abstract
Exposure to environmental pollutants (EP) is associated with a wide range of toxic effects, in particular in testis development. Uranium is a potential pollutant of nuclear industry and over the last few years, its environmental concentrations have increased. In animals, the current procedures for evaluating the potential developmental toxicity of uranium are based on in vivo studies. These methods do not allow to know the direct effects on testicular cells and are obviously excluded for human experiments. Consequently, we have developed an in vitro culture system of the whole testis. In the present study we characterized and validated this organ culture system in both mouse fetal testes and human fetal testes recovered during the first trimester (6-12 weeks) of gestation. We compared the histological aspect, the number of germ cells and the testosterone production, before and after culture. Testicular architecture and intercellular communications were preserved, and organ culture appears as a powerful method for studying the early development of testicular gametogenesis and steroidogenesis in both species. Thus by using this method we will be able to investigate the effects of uranium on mouse and human developing testis. The mouse model will allow us to determine the dose range of interest without restriction of material.
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Affiliation(s)
- R Lambrot
- CEA, DSV/DRR/SEGG/LDRG, 92265 Fontenay-aux-Roses, France.
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14
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Habert R, Delbes G, Duquenne C, Livera G, Levacher C. [Effects of estrogens on the development of the testis during fetal and neonatal life]. ACTA ACUST UNITED AC 2006; 34:970-7. [PMID: 16971153 DOI: 10.1016/j.gyobfe.2006.07.030] [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] [Received: 07/17/2006] [Accepted: 07/28/2006] [Indexed: 11/25/2022]
Abstract
Estrogens are classically known to play a major role in female reproduction but there is now compelling evidence that they may also be involved in the regulation of male reproductive function. In humans, a decrease in sperm count and an increase in the incidences of testicular cancer, cryptorchidism and hypospadia have been observed in many countries over the last 50 years. Male reproductive alterations were also observed in wildlife. Such male reproductive disorders have been attributed to the increase in concentration of xenobiotics, and of xenoestrogens in particular, in the environment and in food. Epidemiological, clinical and experimental studies have suggested that excessive exposure to estrogens during fetal/neonatal life can lead to reproductive disorders in adulthood. Using an in vitro model we showed that estrogens directly affected the development of the fetal testis and we evidenced the existence of periods of sensitivity throughout development. Lastly, we clearly demonstrated that the fetal and neonatal testis is very sensitive to estrogens since the invalidation of estrogen receptor alpha leads to an increase of steroidogenesis and the invalidation of estrogen receptor beta enhances the development of the germ cell lineage in the male.
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Affiliation(s)
- R Habert
- Unité mixte de recherche sur la gamétogenèse et la génotoxicité, Inserm U566, CEA, université Paris-VII, Equipe différenciation et radiobiologie des gonades, CEA-DSV-DRR/SEGG-LDRG, 92265 Fontenay-aux-Roses, France.
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15
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Abstract
Estrogens are classically known to play a major role in female reproduction, but there is now compelling evidence that they may also be involved in the regulation of male reproductive function. In humans, a decrease in sperm count and an increase in the incidences of testicular cancer, cryptorchidism and hypospadia have been observed in many countries over the last 50 years. Male reproductive alterations were also observed in wildlife. Such male reproductive disorders have been attributed to the increase in concentration of xenobiotics, and of xenoestrogens in particular, in the environment and in food. Epidemiological, clinical and experimental studies have suggested that excessive exposure to estrogens during fetal/neonatal life can lead to reproductive disorders in adulthood. Using an in vitro model, we showed that estrogens directly affected the development of the fetal testis. Lastly, we clearly demonstrated that the fetal and neonatal testis is very sensitive to estrogens since the invalidation of estrogen receptor alpha leads to an increase of steroidogenesis and the invalidation of estrogen receptor beta enhances the development of the germ cell lineage in the male.
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Affiliation(s)
- Géraldine Delbès
- Unité mixte de recherche sur la Gamétogenèse et la génotoxicité, Inserm U.566, CEA, Université Paris 7, Equipe Différenciation et radiobiologie des gonades, CEA/DSV/DRR/SEGG/LDRG, BP 6, route du Panorama, 92265 Fontenay-aux-Roses, France
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16
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Abd-Elmaksoud A, Abo-Elmaksoud A, Sinowatz F. Expression and localization of growth factors and their receptors in the mammalian testis. Part I: Fibroblast growth factors and insulin-like growth factors. Anat Histol Embryol 2005; 34:319-34. [PMID: 16159374 DOI: 10.1111/j.1439-0264.2005.00651.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It is now well established that normal development and function of testis are mediated by endocrine and paracrine pathways including hormones, growth factors and cytokines as well as by direct cell-to-cell contacts depending on tight, adhering and gap junctions. In the last two decades, several growth factors were identified in the testis of various mammalian species. Growth factors are shown to promote cell proliferation, regulate tissue differentiation, and modulate organogenesis. Interestingly, most of these peptides are expressed not only in the adult mammalian testis during spermatogenesis but also during testicular morphogenesis in prenatal and postnatal life. Our study was launched to provide an overview of the expression, localization, and putative physiological roles of growth factors and their receptors in the mammalian testis. The growth factors considered in this part of our review are fibroblast growth factors and insulin-like growth factors. These factors are found in testicular cells in prenatal, postnatal, and adult animals and are implicated in the regulation of important testicular activities including testicular cord morphogenesis, modulation of testicular hormone secretion and control of spermatogenesis.
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Affiliation(s)
- A Abd-Elmaksoud
- Institute of Veterinary Anatomy II, University of Munich, Veterinärstrasse 13, D-80539 Munich, Germany
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Liu K, Lehmann KP, Sar M, Young SS, Gaido KW. Gene Expression Profiling Following In Utero Exposure to Phthalate Esters Reveals New Gene Targets in the Etiology of Testicular Dysgenesis1. Biol Reprod 2005; 73:180-92. [PMID: 15728792 DOI: 10.1095/biolreprod.104.039404] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Male reproductive tract abnormalities associated with testicular dysgenesis in humans also occur in male rats exposed gestationally to some phthalate esters. We examined global gene expression in the fetal testis of the rat following in utero exposure to a panel of phthalate esters. Pregnant Sprague-Dawley rats were treated by gavage daily from Gestational Days 12 through 19 with corn oil vehicle (1 ml/kg) or diethyl phthalate (DEP), dimethyl phthalate (DMP), dioctyl tere-phthalate (DOTP), dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP), dipentyl phthalate (DPP), or benzyl butyl phthalate (BBP) at 500 mg/kg per day. Testes were isolated on Gestational Day 19, and global changes in gene expression were determined. Of the approximately 30 000 genes queried, expression of 391 genes was significantly altered following exposure to the developmentally toxic phthalates (DBP, BBP, DPP, and DEHP) relative to the control. The developmentally toxic phthalates were indistinguishable in their effects on global gene expression. No significant changes in gene expression were detected in the nondevelopmentally toxic phthalate group (DMP, DEP, and DOTP). Gene pathways disrupted include those previously identified as targets for DBP, including cholesterol transport and steroidogenesis, as well as newly identified pathways involved in intracellular lipid and cholesterol homeostasis, insulin signaling, transcriptional regulation, and oxidative stress. Additional gene targets include alpha inhibin, which is essential for normal Sertoli cell development, and genes involved with communication between Sertoli cells and gonocytes. The common targeting of these genes by a select group of phthalates indicates a role for their associated molecular pathways in testicular development and offers new insight into the molecular mechanisms of testicular dysgenesis.
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Affiliation(s)
- Kejun Liu
- CIIT Centers for Health Research, Research Triangle Park, North Carolina 27709, USA
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Livera G, Pairault C, Lambrot R, Lelievre-Pegorier M, Saez JM, Habert R, Rouiller-Fabre V. Retinoid-Sensitive Steps in Steroidogenesis in Fetal and Neonatal Rat Testes: In Vitro and In Vivo Studies. Biol Reprod 2004; 70:1814-21. [PMID: 14960491 DOI: 10.1095/biolreprod.103.021451] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Retinoic acid (RA) was recently shown to modify testosterone secretion of the fetal testis in vitro. We characterized this effect by culturing rat testes explanted at various ages, from Fetal Day 14.5 to Postnatal Day 3. In basal medium, RA inhibited, in a dose-dependent manner, both basal and acute LH-stimulated testosterone secretion by testes explanted on Fetal Days 14.5, 15.5, and 16.5. It had no effect on testes from older animals. The negative effect of RA did not result from a diminution in the number of Leydig cells but from a decrease in P450c17 mRNA levels and in LH-stimulated cAMP production. However, the RA-induced decrease in P450C17 mRNA levels was also observed with neonatal testes, suggesting that this enzymatic step is no longer rate limiting at this developmental stage. To study the physiological relevance of RA effects, we used fetuses and neonates issued from mothers fed a vitamin A-deficient (VAD) diet, resulting in a threefold decrease of plasma retinol concentration. On Fetal Day 18.5 and on Posnatal Day 3, testosterone secretion by the testis ex vivo was significantly increased in VAD animals. This shows that the endogenous retinol inhibits differentiation and/or function of fetal Leydig cells before Fetal Day 18.5 and is required for the normal regression of fetal Leydig cell function that occurs after Fetal Day 18.5. In conclusion, our results show that retinoids play a negative role on the steroidogenic activity during the differentiation of rat fetal Leydig cells.
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Affiliation(s)
- G Livera
- INSERM U566-CEA-UNIVERSITE PARIS 7, CEA/DSV/DRR BP6, 92265 Fontenay aux Roses, France
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Geigerseder C, Doepner RFG, Thalhammer A, Krieger A, Mayerhofer A. Stimulation of TM3 Leydig cell proliferation via GABA(A) receptors: a new role for testicular GABA. Reprod Biol Endocrinol 2004; 2:13. [PMID: 15040802 PMCID: PMC416489 DOI: 10.1186/1477-7827-2-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Accepted: 03/24/2004] [Indexed: 11/10/2022] Open
Abstract
The neurotransmitter gamma-aminobutyric acid (GABA) and subtypes of GABA receptors were recently identified in adult testes. Since adult Leydig cells possess both the GABA biosynthetic enzyme glutamate decarboxylase (GAD), as well as GABA(A) and GABA(B) receptors, it is possible that GABA may act as auto-/paracrine molecule to regulate Leydig cell function. The present study was aimed to examine effects of GABA, which may include trophic action. This assumption is based on reports pinpointing GABA as regulator of proliferation and differentiation of developing neurons via GABA(A) receptors. Assuming such a role for the developing testis, we studied whether GABA synthesis and GABA receptors are already present in the postnatal testis, where fetal Leydig cells and, to a much greater extend, cells of the adult Leydig cell lineage proliferate. Immunohistochemistry, RT-PCR, Western blotting and a radioactive enzymatic GAD assay evidenced that fetal Leydig cells of five-six days old rats possess active GAD protein, and that both fetal Leydig cells and cells of the adult Leydig cell lineage possess GABA(A) receptor subunits. TM3 cells, a proliferating mouse Leydig cell line, which we showed to possess GABA(A) receptor subunits by RT-PCR, served to study effects of GABA on proliferation. Using a colorimetric proliferation assay and Western Blotting for proliferating cell nuclear antigen (PCNA) we demonstrated that GABA or the GABA(A) agonist isoguvacine significantly increased TM3 cell number and PCNA content in TM3 cells. These effects were blocked by the GABA(A) antagonist bicuculline, implying a role for GABA(A) receptors. In conclusion, GABA increases proliferation of TM3 Leydig cells via GABA(A) receptor activation and proliferating Leydig cells in the postnatal rodent testis bear a GABAergic system. Thus testicular GABA may play an as yet unrecognized role in the development of Leydig cells during the differentiation of the testicular interstitial compartment.
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Affiliation(s)
- Christof Geigerseder
- Anatomisches Institut der Ludwig-Maximilians-Universität München, Biedersteinerstr.29, D-80802 München, Germany
| | - Richard FG Doepner
- Anatomisches Institut der Ludwig-Maximilians-Universität München, Biedersteinerstr.29, D-80802 München, Germany
| | - Andrea Thalhammer
- Anatomisches Institut der Ludwig-Maximilians-Universität München, Biedersteinerstr.29, D-80802 München, Germany
| | - Annette Krieger
- Anatomisches Institut der Ludwig-Maximilians-Universität München, Biedersteinerstr.29, D-80802 München, Germany
| | - Artur Mayerhofer
- Anatomisches Institut der Ludwig-Maximilians-Universität München, Biedersteinerstr.29, D-80802 München, Germany
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