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Singh P, Aggarwal LM, Parry SA, Raman MJ. Radiation dosimetry and repair kinetics of DNA damage foci in mouse pachytene spermatocyte and round spermatid stages. Mutagenesis 2019; 33:231-239. [PMID: 30239864 DOI: 10.1093/mutage/gey007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 04/19/2018] [Indexed: 12/23/2022] Open
Abstract
Accurate quantification of DNA double strand breaks (DSB) in testicular germ cells is difficult because of cellular heterogeneity and the presence of endogenous γH2AX. Here, we used confocal microscopy to quantify DNA damage and repair kinetics following γ-irradiation (0.5-4 Gy) in three major mouse male germ cell stages, early and late pachytene spermatocytes and round spermatids (RSs), following a defined post irradiation time course. Dose-response curves showing linear best fit validated γH2AX focus as a rapid biodosimetric tool in these substages in response to whole body in vivo exposure. Stage specific foci yield/dose and repair kinetics demonstrated differential radiosensitivity and repair efficiency: early pachytenes (EP) repaired most rapidly and completely followed by late pachytene (LP) and RSs. Repair kinetics for all three stages followed 'exponential decay' in response to each radiation dose. In pachytenes immediate colocalisation of γH2AX and 53BP1, which participates in non-homologous end-joining repair pathway, was followed by dissociation from the major focal area of γH2AX by 4 h demonstrating ongoing DSB repair. These results confirm the differential radiosensitivity and repair kinetics of DSBs in male germ cells at different stages. Taken together, our results provide a simple and accurate method for assessing DNA damage and repair kinetics during spermatogenesis.
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Affiliation(s)
- Priti Singh
- Cytogenetics Laboratory, Department of Zoology, Centre of Advanced Study, India
| | - Lalit Mohan Aggarwal
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Stephen A Parry
- Cornell Statistical Consulting Unit, Cornell University, Ithaca, NY, USA
| | - Mercy J Raman
- Cytogenetics Laboratory, Department of Zoology, Centre of Advanced Study, India
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2
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Yuan JT, Gatti DM, Philip VM, Kasparek S, Kreuzman AM, Mansky B, Sharif K, Taterra D, Taylor WM, Thomas M, Ward JO, Holmes A, Chesler EJ, Parker CC. Genome-wide association for testis weight in the diversity outbred mouse population. Mamm Genome 2018; 29:310-324. [PMID: 29691636 DOI: 10.1007/s00335-018-9745-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/16/2018] [Indexed: 12/28/2022]
Abstract
Testis weight is a genetically mediated trait associated with reproductive efficiency across numerous species. We sought to evaluate the genetically diverse, highly recombinant Diversity Outbred (DO) mouse population as a tool to identify and map quantitative trait loci (QTLs) associated with testis weight. Testis weights were recorded for 502 male DO mice and the mice were genotyped on the GIGAMuga array at ~ 143,000 SNPs. We performed a genome-wide association analysis and identified one significant and two suggestive QTLs associated with testis weight. Using bioinformatic approaches, we developed a list of candidate genes and identified those with known roles in testicular size and development. Candidates of particular interest include the RNA demethylase gene Alkbh5, the cyclin-dependent kinase inhibitor gene Cdkn2c, the dynein axonemal heavy chain gene Dnah11, the phospholipase D gene Pld6, the trans-acting transcription factor gene Sp4, and the spermatogenesis-associated gene Spata6, each of which has a human ortholog. Our results demonstrate the utility of DO mice in high-resolution genetic mapping of complex traits, enabling us to identify developmentally important genes in adult mice. Understanding how genetic variation in these genes influence testis weight could aid in the understanding of mechanisms of mammalian reproductive function.
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Affiliation(s)
- Joshua T Yuan
- Department of Computer Science, Program in Molecular Biology & Biochemistry, Middlebury College, Middlebury, VT, 05753, USA
| | - Daniel M Gatti
- The Jackson Laboratory, 610 Main Street, Bar Harbor, ME, 04609, USA
| | - Vivek M Philip
- The Jackson Laboratory, 610 Main Street, Bar Harbor, ME, 04609, USA
| | - Steven Kasparek
- Department of Psychology, Middlebury College, Middlebury, VT, 05753, USA
| | - Andrew M Kreuzman
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Benjamin Mansky
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Kayvon Sharif
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Dominik Taterra
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Walter M Taylor
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Mary Thomas
- Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA
| | - Jeremy O Ward
- Department of Biology, Program in Molecular Biology & Biochemistry, Middlebury College, Middlebury, VT, 05753, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcoholism and Alcohol Abuse (NIAAA), US National Institutes of Health (NIH), Bethesda, MD, USA
| | - Elissa J Chesler
- The Jackson Laboratory, 610 Main Street, Bar Harbor, ME, 04609, USA
| | - Clarissa C Parker
- Department of Psychology, Middlebury College, Middlebury, VT, 05753, USA. .,Program in Neuroscience, Middlebury College, Middlebury, VT, 05753, USA.
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3
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Sharma S, Portela JMD, Langenstroth-Röwer D, Wistuba J, Neuhaus N, Schlatt S. Male germline stem cells in non-human primates. Primate Biol 2017; 4:173-184. [PMID: 32110705 PMCID: PMC7041516 DOI: 10.5194/pb-4-173-2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/17/2017] [Indexed: 12/22/2022] Open
Abstract
Over the past few decades, several studies have attempted to decipher the
biology of mammalian germline stem cells (GSCs). These studies provide
evidence that regulatory mechanisms for germ cell specification and migration
are evolutionarily conserved across species. The characteristics and
functions of primate GSCs are highly distinct from rodent species; therefore
the findings from rodent models cannot be extrapolated to primates. Due to
limited availability of human embryonic and testicular samples for research
purposes, two non-human primate models (marmoset and macaque monkeys) are
extensively employed to understand human germline development and
differentiation. This review provides a broader introduction to the in vivo
and in vitro germline stem cell terminology from primordial to
differentiating germ cells. Primordial germ cells (PGCs) are the most
immature germ cells colonizing the gonad prior to sex differentiation into
testes or ovaries. PGC specification and migratory patterns among different
primate species are compared in the review. It also reports the distinctions
and similarities in expression patterns of pluripotency markers (OCT4A,
NANOG, SALL4 and LIN28) during embryonic developmental stages, among
marmosets, macaques and humans. This review presents a comparative summary
with immunohistochemical and molecular evidence of germ cell marker
expression patterns during postnatal developmental stages, among humans and
non-human primates. Furthermore, it reports findings from the recent
literature investigating the plasticity behavior of germ cells and stem cells
in other organs of humans and monkeys. The use of non-human primate models
would enable bridging the knowledge gap in primate GSC research and
understanding the mechanisms involved in germline development. Reported
similarities in regulatory mechanisms and germ cell expression profile in
primates demonstrate the preclinical significance of monkey models for
development of human fertility preservation strategies.
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Affiliation(s)
- Swati Sharma
- Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany.,These authors contributed equally to this work
| | - Joana M D Portela
- Center for Reproductive Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands.,These authors contributed equally to this work
| | - Daniel Langenstroth-Röwer
- Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany
| | - Joachim Wistuba
- Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany
| | - Nina Neuhaus
- Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany
| | - Stefan Schlatt
- Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany
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Watanabe H, Kohda A, Komura JI, Tateno H. Preservation of chromosomal integrity in murine spermatozoa derived from gonocytes and spermatogonial stem cells surviving prenatal and postnatal exposure to γ-rays in mice. Mol Reprod Dev 2017; 84:638-648. [PMID: 28481028 DOI: 10.1002/mrd.22832] [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: 12/29/2016] [Revised: 04/07/2017] [Accepted: 05/02/2017] [Indexed: 11/08/2022]
Abstract
Pre- and postnatal male mice were acutely (659-690 mGy/min) and continuously (0.303 mGy/min) exposed to 2 Gy γ-rays to evaluate spermatogenic potential and chromosome damage in their germ cells as adults. Acute irradiation on Days 15.5, 16.5, and 17.5 post-coitus affected testicular development, as a result of massive quiescent gonocyte loss; the majority of the seminiferous tubules in these testes were devoid of germ cells. Acute irradiation on Days 18.5 and 19.5 post-coitus had less effect on testicular development and spermatogenesis, even though germ cells were quiescent gonocytes on these days. Adverse effects on testicular development and spermatogenesis were observed following continuous irradiation between Days 14.5 and 19.5 post-coitus. Exposure to acute and continuous postnatal irradiation after the differentiation of spermatogonial stem cells and spermatogonia resulted in nearly all of the seminiferous tubules exhibiting spermatogenesis. Neither acute nor continuous irradiation was responsible for the increased number of multivalent chromosomes in primary-spermatocyte descendents of the exposed gonocytes. In contrast, a significant increase in cells with multivalent chromosomes was observed following acute irradiation on Days 4 and 11 post-partum. No significant increases in unstable structural chromosomal aberrations or aneuploidy in spermatozoa were observed, regardless of cell stage at irradiation or the radiation dose-rate. Thus, murine germ cells that survive prenatal and postnatal irradiation can restore spermatogenesis and produce viable spermatozoa without chromosome damage. These findings may provide a better understanding of reproductive potential following accidental, environmental, or therapeutic irradiation during the prenatal and postnatal periods in humans.
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Affiliation(s)
- Hiroyuki Watanabe
- Department of Biological Sciences, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Atsushi Kohda
- Department of Radiobiology, Institute for Environmental Sciences, Rokkasho, Kamikita, Aomori, Japan
| | - Jun-Ichiro Komura
- Department of Radiobiology, Institute for Environmental Sciences, Rokkasho, Kamikita, Aomori, Japan
| | - Hiroyuki Tateno
- Department of Biological Sciences, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
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5
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Paul C, Nagano M, Robaire B. Aging Results in Molecular Changes in an Enriched Population of Undifferentiated Rat Spermatogonia1. Biol Reprod 2013; 89:147. [DOI: 10.1095/biolreprod.113.112995] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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6
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Haeri SA, Rajabi H, Fazelipour S, Hosseinimehr SJ. Carnosine mitigates apoptosis and protects testicular seminiferous tubules from gamma-radiation-induced injury in mice. Andrologia 2013; 46:1041-6. [DOI: 10.1111/and.12193] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2013] [Indexed: 12/20/2022] Open
Affiliation(s)
- S. A. Haeri
- Faculty of Medical Sciences; Department of Medical Physics; Tarbiat Modares University; Tehran Iran
| | - H. Rajabi
- Faculty of Medical Sciences; Department of Medical Physics; Tarbiat Modares University; Tehran Iran
| | - S. Fazelipour
- Faculty of Medical Sciences; Department of Anatomy; Islamic Azad University; Tehran Iran
| | - S. J. Hosseinimehr
- Faculty of Pharmacy; Department of Radiopharmacy; Mazandaran University of Medical Sciences; Sari Iran
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7
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Rad54 is required for the normal development of male and female germ cells and contributes to the maintainance of their genome integrity after genotoxic stress. Cell Death Dis 2013; 4:e774. [PMID: 23949223 PMCID: PMC3763443 DOI: 10.1038/cddis.2013.281] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/25/2013] [Accepted: 07/02/2013] [Indexed: 12/31/2022]
Abstract
Rad54 is an important factor in the homologous recombination pathway of DNA double-strand break repair. However, Rad54 knockout (KO) mice do not exhibit overt phenotypes at adulthood, even when exposed to radiation. In this study, we show that in Rad54 KO mouse the germline is actually altered. Compared with the wild-type (WT) animals, these mice have less premeiotic germ cells. This germ cell loss is found as early as in E11.5 embryos, suggesting an early failure during mutant primordial germ cells development. Both testicular and ovarian KO germ cells exhibited high radiation sensitivity leading to a long-term gametogenesis defect at adulthood. The KO female germline was particularly affected displaying decreased litter size or sterility. Spermatogenesis recovery after irradiation was slower and incomplete in Rad54 KO mice compared with that of WT mice, suggesting that loss of germ stem cell precursors is not fully compensated along the successive rounds of spermatogenesis. Finally, spermatogenesis recovery after postnatal irradiation is in part regulated by glial-cell-line-derived neurotrophic factor (GDNF) in KO but not in irradiated WT mice, suggesting that Sertoli cell GDNF production is stimulated upon substantial germ cell loss only. Our findings suggest that Rad54 has a key function in maintaining genomic integrity of the developing germ cells.
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8
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Sun C, López Arriaza JR, Mueller RL. Slow DNA loss in the gigantic genomes of salamanders. Genome Biol Evol 2013; 4:1340-8. [PMID: 23175715 PMCID: PMC3542557 DOI: 10.1093/gbe/evs103] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Evolutionary changes in genome size result from the combined effects of mutation, natural
selection, and genetic drift. Insertion and deletion mutations (indels) directly impact
genome size by adding or removing sequences. Most species lose more DNA through small
indels (i.e., ∼1–30 bp) than they gain, which can result in genome reduction
over time. Because this rate of DNA loss varies across species, small indel dynamics have
been suggested to contribute to genome size evolution. Species with extremely large
genomes provide interesting test cases for exploring the link between small indels and
genome size; however, most large genomes remain relatively unexplored. Here, we examine
rates of DNA loss in the tetrapods with the largest genomes—the salamanders. We used
low-coverage genomic shotgun sequence data from four salamander species to examine
patterns of insertion, deletion, and substitution in neutrally evolving non-long terminal
repeat (LTR) retrotransposon sequences. For comparison, we estimated genome-wide DNA loss
rates in non-LTR retrotransposon sequences from five other vertebrate genomes:
Anolis carolinensis, Danio rerio, Gallus
gallus, Homo sapiens, and Xenopus tropicalis.
Our results show that salamanders have significantly lower rates of DNA loss than do other
vertebrates. More specifically, salamanders experience lower numbers of deletions relative
to insertions, and both deletions and insertions are skewed toward smaller sizes. On the
basis of these patterns, we conclude that slow DNA loss contributes to genomic gigantism
in salamanders. We also identify candidate molecular mechanisms underlying these
differences and suggest that natural variation in indel dynamics provides a unique
opportunity to study the basis of genome stability.
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Affiliation(s)
- Cheng Sun
- Department of Biology, Colorado State University, CO, USA
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9
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Lutzmann M, Grey C, Traver S, Ganier O, Maya-Mendoza A, Ranisavljevic N, Bernex F, Nishiyama A, Montel N, Gavois E, Forichon L, de Massy B, Méchali M. MCM8- and MCM9-deficient mice reveal gametogenesis defects and genome instability due to impaired homologous recombination. Mol Cell 2012; 47:523-34. [PMID: 22771120 DOI: 10.1016/j.molcel.2012.05.048] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/21/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
Abstract
We generated knockout mice for MCM8 and MCM9 and show that deficiency for these genes impairs homologous recombination (HR)-mediated DNA repair during gametogenesis and somatic cells cycles. MCM8(-/-) mice are sterile because spermatocytes are blocked in meiotic prophase I, and females have only arrested primary follicles and frequently develop ovarian tumors. MCM9(-/-) females also are sterile as ovaries are completely devoid of oocytes. In contrast, MCM9(-/-) testes produce spermatozoa, albeit in much reduced quantity. Mcm8(-/-) and Mcm9(-/-) embryonic fibroblasts show growth defects and chromosomal damage and cannot overcome a transient inhibition of replication fork progression. In these cells, chromatin recruitment of HR factors like Rad51 and RPA is impaired and HR strongly reduced. We further demonstrate that MCM8 and MCM9 form a complex and that they coregulate their stability. Our work uncovers essential functions of MCM8 and MCM9 in HR-mediated DSB repair during gametogenesis, replication fork maintenance, and DNA repair.
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Affiliation(s)
- Malik Lutzmann
- DNA Replication and Genome Dynamics, Institute of Human Genetics, CNRS, 141 Rue de la Cardonille, 34396 Montpellier, Cedex 5, France
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10
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Svensson JP, Fry RC, Wang E, Somoza LA, Samson LD. Identification of novel human damage response proteins targeted through yeast orthology. PLoS One 2012; 7:e37368. [PMID: 22615993 PMCID: PMC3353887 DOI: 10.1371/journal.pone.0037368] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 04/21/2012] [Indexed: 01/09/2023] Open
Abstract
Studies in Saccharomyces cerevisiae show that many proteins influence cellular survival upon exposure to DNA damaging agents. We hypothesized that human orthologs of these S. cerevisiae proteins would also be required for cellular survival after treatment with DNA damaging agents. For this purpose, human homologs of S. cerevisiae proteins were identified and mapped onto the human protein-protein interaction network. The resulting human network was highly modular and a series of selection rules were implemented to identify 45 candidates for human toxicity-modulating proteins. The corresponding transcripts were targeted by RNA interference in human cells. The cell lines with depleted target expression were challenged with three DNA damaging agents: the alkylating agents MMS and 4-NQO, and the oxidizing agent t-BuOOH. A comparison of the survival revealed that the majority (74%) of proteins conferred either sensitivity or resistance. The identified human toxicity-modulating proteins represent a variety of biological functions: autophagy, chromatin modifications, RNA and protein metabolism, and telomere maintenance. Further studies revealed that MMS-induced autophagy increase the survival of cells treated with DNA damaging agents. In summary, we show that damage recovery proteins in humans can be identified through homology to S. cerevisiae and that many of the same pathways are represented among the toxicity modulators.
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Affiliation(s)
- J. Peter Svensson
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Rebecca C. Fry
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Computation and Systems Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Emma Wang
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Luis A. Somoza
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Leona D. Samson
- Biological Engineering Department, Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Computation and Systems Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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12
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Yang Y, Honaramooz A. Efficient purification of neonatal porcine gonocytes with Nycodenz and differential plating. Reprod Fertil Dev 2011; 23:496-505. [DOI: 10.1071/rd10042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 11/01/2010] [Indexed: 12/24/2022] Open
Abstract
Gonocytes are the only type of germ cells present in the postnatal testis and give rise to spermatogonial stem cells. Purification of gonocytes has important implications for the study and manipulation of these cells and may provide insights for the ongoing investigation of the male germline stem cells. To obtain a pure population of gonocytes from piglet testis cells, a wide range of Nycodenz concentrations were investigated for density gradient centrifugation. We also examined differential plating of testis cells for various culture durations with different extracellular matrix (ECM) components (fibronectin, poly-d-lysine, poly-l-lysine, laminin and collagen Types I and IV). Gonocytes were highly enriched in pellets of testis cells after using 17% Nycodenz centrifugation to a purity of 81 ± 9%. After culturing testis cells on plates precoated with different ECM components for 120 min, the proportion of gonocytes increased among non-adherent cells (suspended in the medium), with fibronectin or poly-d-lysine resulting in the greatest (up to 85%) and laminin in the lowest (54%) gonocyte proportion. Combining the most promising ECM coatings (fibronectin and poly-d-lysine) and further extension of their culture duration to 240 min did not improve final gonocyte purity. However, centrifugation with 17% Nycodenz followed by differential plating with fibronectin and poly-d-lysine coating further purified gonocytes among the collected cells to >90%. These results provide a simple, quick and efficient approach for obtaining highly enriched populations of piglet gonocytes for use in the study and manipulation of these germline stem cells.
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Albert S, Ehmcke J, Wistuba J, Eildermann K, Behr R, Schlatt S, Gromoll J. Germ cell dynamics in the testis of the postnatal common marmoset monkey (Callithrix jacchus). Reproduction 2010; 140:733-42. [DOI: 10.1530/rep-10-0235] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The seminiferous epithelium in the nonhuman primate Callithrix jacchus is similarly organized to man. This monkey has therefore been used as a preclinical model for spermatogenesis and testicular stem cell physiology. However, little is known about the developmental dynamics of germ cells in the postnatal primate testis. In this study, we analyzed testes of newborn, 8-week-old, and adult marmosets employing immunohistochemistry using pluripotent stem cell and germ cell markers DDX4 (VASA), POU5F1 (OCT3/4), and TFAP2C (AP-2γ). Stereological and morphometric techniques were applied for quantitative analysis of germ cell populations and testicular histological changes. Quantitative RT-PCR (qRT-PCR) of testicular mRNA was applied using 16 marker genes establishing the corresponding profiles during postnatal testicular development. Testis size increased during the first 8 weeks of life with the main driver being longitudinal outgrowth of seminiferous cords. The number of DDX4-positive cells per testis doubled between birth and 8 weeks of age whereas TFAP2C- and POU5F1-positive cells remained unchanged. This increase in DDX4-expressing cells indicates dynamic growth of the differentiated A-spermatogonial population. The presence of cells expressing POU5F1 and TFAP2C after 8 weeks reveals the persistence of less differentiated germ cells. The mRNA and protein profiles determined by qRT-PCR and western blot in newborn, 8-week-old, and adult marmosets corroborated the immunohistochemical findings. In conclusion, we demonstrated the presence of distinct spermatogonial subpopulations in the primate testis exhibiting different dynamics during early testicular development. Our study demonstrates the suitability of the marmoset testis as a model for human testicular development.
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15
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Bowen JM, Tsykin A, Stringer AM, Logan RM, Gibson RJ, Keefe DMK. Kinetics and regional specificity of irinotecan-induced gene expression in the gastrointestinal tract. Toxicology 2010; 269:1-12. [PMID: 20097248 DOI: 10.1016/j.tox.2009.12.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 12/18/2009] [Accepted: 12/21/2009] [Indexed: 12/31/2022]
Abstract
Gastrointestinal toxicity remains a significant and dose-limiting complication of cancer treatment. While the pathophysiology is becoming clearer, considerable gaps in the knowledge remain surrounding the timing and site-specific gene changes which occur in response to insult. As such, this study aimed to assess gene expression profiles in a number of regions along the gastrointestinal tract following treatment with the chemotherapy agent, irinotecan, and correlate them with markers of cell death and tissue damage. Data analysis of microarray results found that genes involved in apoptosis, mitogen activated kinase (MAPK) signalling and inflammation were upregulated within 6h, while genes involved in cell proliferation, wound healing and blood vessel formation were upregulated at later time points up to 72 h. Cell death was significantly increased at 6 and 24h, and the stomach showed the lowest severity of overt tissue damage. Real time PCR of MAPK signalling pathway genes found that the jejunum and colon had significantly increased expression in a number of genes at 72 h, where as the stomach was unchanged. These results indicate that overall severity of tissue damage may be determined by precisely timed target gene responses specific to each region. Therapeutic targeting of key gene responses at the appropriate time point may prove to be effective for prevention of chemotherapy-induced gastrointestinal damage.
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16
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Forand A, Bernardino-Sgherri J. A critical role of PUMA in maintenance of genomic integrity of murine spermatogonial stem cell precursors after genotoxic stress. Cell Res 2009; 19:1018-30. [PMID: 19417777 DOI: 10.1038/cr.2009.50] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Neonatal gonocytes are precursors of spermatogonial stem cells. Preserving their integrity by elimination of damaged germ cells may be crucial to avoid the transmission of genetic alterations to progeny. Using gamma-irradiation, we investigated by immunohistochemistry, flow cytometry and real-time PCR components of the death machinery in neonatal gonocytes. Their death was correlated with caspase 3 activation but not with AIF translocation into the nucleus. The in vivo contribution of both the extrinsic and the intrinsic pathways was then investigated. We focused on the roles of TRAIL/Death Receptor 5 (DR5) and PUMA. Our results were validated using knockout mice. Whereas DR5 expression was upregulated at the cell surface after radiation, caspase 8 was not activated. However, we detected caspase 9 cleavage associated with cytochrome c release. In mice deficient for PUMA, radiation-induced gonocyte apoptosis was reduced, whereas invalidation of TRAIL had no effect. Overall, our results show that genotoxic stress-induced apoptosis of gonocytes is caspase-dependent and involves almost exclusively the intrinsic pathway. Furthermore, PUMA plays a critical role in the maintenance of genomic integrity of spermatogonial stem cell precursors.
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Affiliation(s)
- Anne Forand
- CEA, DSV, iRCM, SCSR, Laboratory of Differentiation and Radiobiology of Gonads, Fontenay aux Roses F-92265, France
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17
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Zinc-finger nucleases: a powerful tool for genetic engineering of animals. Transgenic Res 2009; 19:363-71. [DOI: 10.1007/s11248-009-9323-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 09/10/2009] [Indexed: 10/20/2022]
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