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Wong HN, Chen T, Wang PJ, Holzman LB. ARF6, a component of intercellular bridges, is essential for spermatogenesis in mice. Dev Biol 2024; 508:46-63. [PMID: 38242343 DOI: 10.1016/j.ydbio.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/05/2024] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
Male germ cells are connected by intercellular bridges (ICBs) in a syncytium due to incomplete cytokinesis. Syncytium is thought to be important for synchronized germ cell development by interchange of cytoplasmic factors via ICBs. Mammalian ADP-ribosylation factor 6 (ARF6) is a small GTPase that is involved in many cellular mechanisms including but not limited to regulating cellular structure, motility, vesicle trafficking and cytokinesis. ARF6 localizes to ICBs in spermatogonia and spermatocytes in mice. Here we report that mice with global depletion of ARF6 in adulthood using Ubc-CreERT2 display no observable phenotypes but are male sterile. ARF6-deficient males display a progressive loss of germ cells, including LIN28A-expressing spermatogonia, and ultimately develop Sertoli-cell-only syndrome. Specifically, intercellular bridges are lost in ARF6-deficient testis. Furthermore, germ cell-specific inactivation using the Ddx4-CreERT2 results in the same testicular morphological phenotype, showing the germ cell-intrinsic requirement of ARF6. Therefore, ARF6 is essential for spermatogenesis in mice and this function is conserved from Drosophila to mammals.
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Affiliation(s)
- Hetty N Wong
- Renal, Electrolyte, and Hypertension Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Tingfang Chen
- Department of Genetics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - P Jeremy Wang
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, 19104, USA
| | - Lawrence B Holzman
- Renal, Electrolyte, and Hypertension Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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2
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Pan B, Yuan S, Mayernik L, Yap YT, Moin K, Chung CS, Maddipati K, Krawetz SA, Zhang Z, Hess RA, Chen X. Disrupted intercellular bridges and spermatogenesis in fatty acyl-CoA reductase 1 knockout mice: A new model of ether lipid deficiency. FASEB J 2023; 37:e22908. [PMID: 37039784 PMCID: PMC10150578 DOI: 10.1096/fj.202201848r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/10/2023] [Accepted: 03/24/2023] [Indexed: 04/12/2023]
Abstract
Peroxisomal fatty acyl-CoA reductase 1 (FAR1) is a rate-limiting enzyme for ether lipid (EL) synthesis. Gene mutations in FAR1 cause a rare human disease. Furthermore, altered EL homeostasis has also been associated with various prevalent human diseases. Despite their importance in human health, the exact cellular functions of FAR1 and EL are not well-understood. Here, we report the generation and initial characterization of the first Far1 knockout (KO) mouse model. Far1 KO mice were subviable and displayed growth retardation. The adult KO male mice had smaller testes and were infertile. H&E and immunofluorescent staining showed fewer germ cells in seminiferous tubules. Round spermatids were present but no elongated spermatids or spermatozoa were observed, suggesting a spermatogenesis arrest at this stage. Large multi-nucleated giant cells (MGC) were found lining the lumen of seminiferous tubules with many of them undergoing apoptosis. The immunofluorescent signal of TEX14, an essential component of intercellular bridges (ICB) between developing germ cells, was greatly reduced and mislocalized in KO testis, suggesting the disrupted ICBs as an underlying cause of MGC formation. Integrative analysis of our total testis RNA-sequencing results and published single-cell RNA-sequencing data unveiled cell type-specific molecular alterations underlying the spermatogenesis arrest. Many genes essential for late germ cell development showed dramatic downregulation, whereas genes essential for extracellular matrix dynamics and cell-cell interactions were among the most upregulated genes. Together, this work identified the cell type-specific requirement of ELs in spermatogenesis and suggested a critical role of Far1/ELs in the formation/maintenance of ICB during meiosis.
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Affiliation(s)
- Bo Pan
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Shuo Yuan
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
- Department of Occupational and Environmental Medicine, School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Linda Mayernik
- Department of Pharmacology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Yi Tian Yap
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Kamiar Moin
- Department of Pharmacology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Charles S. Chung
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Krishnarao Maddipati
- Department of Pathology, Wayne State University, School of Medicine, Detroit, Michigan, USA
| | - Stephen A. Krawetz
- Department of Obstetrics & Gynecology, Wayne State University, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Zhibing Zhang
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
- Department of Obstetrics & Gynecology, Wayne State University, Detroit, Michigan, USA
| | - Rex A. Hess
- Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Xuequn Chen
- Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan, USA
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3
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Legrand JMD, Hobbs RM. Defining Gene Function in Spermatogonial Stem Cells Through Conditional Knockout Approaches. Methods Mol Biol 2023; 2656:261-307. [PMID: 37249877 DOI: 10.1007/978-1-0716-3139-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Mammalian male fertility is maintained throughout life by a population of self-renewing mitotic germ cells known as spermatogonial stem cells (SSCs). Much of our current understanding regarding the molecular mechanisms underlying SSC activity is derived from studies using conditional knockout mouse models. Here, we provide a guide for the selection and use of mouse strains to develop conditional knockout models for the study of SSCs, as well as their precursors and differentiation-committed progeny. We describe Cre recombinase-expressing strains, breeding strategies to generate experimental groups, and treatment regimens for inducible knockout models and provide advice for verifying and improving conditional knockout efficiency. This resource can be beneficial to those aiming to develop conditional knockout models for the study of SSC development and postnatal function.
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Affiliation(s)
- Julien M D Legrand
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, Monash University, Clayton, VIC, Australia
| | - Robin M Hobbs
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia.
- Department of Molecular and Translational Sciences, Monash University, Clayton, VIC, Australia.
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4
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Touré A. Importance of SLC26 Transmembrane Anion Exchangers in Sperm Post-testicular Maturation and Fertilization Potential. Front Cell Dev Biol 2019; 7:230. [PMID: 31681763 PMCID: PMC6813192 DOI: 10.3389/fcell.2019.00230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
In mammals, sperm cells produced within the testis are structurally differentiated but remain immotile and are unable to fertilize the oocyte unless they undergo a series of maturation events during their transit in the male and female genital tracts. This post-testicular functional maturation is known to rely on the micro-environment of both male and female genital tracts, and is tightly controlled by the pH of their luminal milieus. In particular, within the epididymis, the establishment of a low bicarbonate (HCO3–) concentration contributes to luminal acidification, which is necessary for sperm maturation and subsequent storage in a quiescent state. Following ejaculation, sperm is exposed to the basic pH of the female genital tract and bicarbonate (HCO3–), calcium (Ca2+), and chloride (Cl–) influxes induce biochemical and electrophysiological changes to the sperm cells (cytoplasmic alkalinization, increased cAMP concentration, and protein phosphorylation cascades), which are indispensable for the acquisition of fertilization potential, a process called capacitation. Solute carrier 26 (SLC26) members are conserved membranous proteins that mediate the transport of various anions across the plasma membrane of epithelial cells and constitute important regulators of pH and HCO3– concentration. Most SLC26 members were shown to physically interact and cooperate with the cystic fibrosis transmembrane conductance regulator channel (CFTR) in various epithelia, mainly by stimulating its Cl– channel activity. Among SLC26 members, the function of SLC26A3, A6, and A8 were particularly investigated in the male genital tract and the sperm cells. In this review, we will focus on SLC26s contributions to ionic- and pH-dependent processes during sperm post-testicular maturation. We will specify the current knowledge regarding their functions, based on data from the literature generated by means of in vitro and in vivo studies in knock-out mouse models together with genetic studies of infertile patients. We will also discuss the limits of those studies, the current research gaps and identify some key points for potential developments in this field.
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Affiliation(s)
- Aminata Touré
- INSERM U1016, Centre National de la Recherche Scientifique, UMR 8104, Institut Cochin, Université de Paris, Paris, France
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5
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Chen K, Chen S, Xu J, Yu Y, Liu Z, Tan A, Huang Y. Maelstrom regulates spermatogenesis of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 109:43-51. [PMID: 30970276 DOI: 10.1016/j.ibmb.2019.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/03/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
The spermatogenesis of animal is essential for the reproduction and a very large number of genes participate in this procession. The Maelstrom (Mael) is identified essential for spermatogenesis in both Drosophila and mouse, though the mechanisms appear to differ. It was initially found that Mael gene is necessary for axis specification of oocytes in Drosophila, and recent studies suggested that Mael participates in the piRNA pathway. In this study, we obtained Bombyx mori Mael mutants by using a binary transgenic CRISPR/Cas9 system and analyzed the function of Mael in B. mori, a model lepidopteran insect. The results showed that BmMael is not necessary for piRNA pathway in the ovary of silkworm, whereas it might be essential for transposon elements (TEs) repression in testis. The BmMael mutation resulted in male sterility, and further analysis established that BmMael was essential for spermatogenesis. The spermatogenesis defects occurred in the elongation stage and resulted in nuclei concentration arrest. RNA-seq and qRT-PCR analyses demonstrated that spermatogenesis defects were associated with tight junctions and apoptosis. We also found that BmMael was not involved in the silkworm sex determination pathway. Our data provide insights into the biological function of BmMael in male spermatogenesis and might be useful for developing novel methods to control lepidopteron pests.
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Affiliation(s)
- Kai Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shuqing Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Ye Yu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zulian Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Anjiang Tan
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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6
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Świątek P, Urbisz AZ. Architecture and Life History of Female Germ-Line Cysts in Clitellate Annelids. Results Probl Cell Differ 2019; 68:515-551. [PMID: 31598870 DOI: 10.1007/978-3-030-23459-1_21] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Animal female and male germ-line cells often form syncytial units termed cysts, clusters, or clones. Within these cysts, the cells remain interconnected by specific cell junctions known as intercellular bridges or ring canals, which enable cytoplasm to be shared and macromolecules and organelles to be exchanged between cells. Numerous analyses have shown that the spatial organization of cysts and their functioning may differ between the sexes and taxa. The vast majority of our knowledge about the formation and functioning of germ-line cysts comes from studies of model species (mainly Drosophila melanogaster); the other systems of the cyst organization and functioning are much less known and are sometimes overlooked. Here, we present the current state of the knowledge of female germ-line cysts in clitellate annelids (Clitellata), which is a monophyletic taxon of segmented worms (Annelida). The organization of germ-line cysts in clitellates differs markedly from that of the fruit fly and vertebrates. In Clitellata, germ cells are not directly connected one to another, but, as a rule, each cell has one ring canal that connects it to an anuclear central cytoplasmic core, a cytophore. Thus, this pattern of cell distribution is similar to the germ-line cysts of Caenorhabditis elegans. The last decade of studies has revealed that although clitellate female germ-line cysts have a strong morphological plasticity, e.g., cysts may contain from 16 to as many as 2500 cells, the oogenesis always shows a meroistic mode, i.e., the interconnected cells take on different fates; a few (sometimes only one) become oocytes, whereas the rest play the role of supporting (nurse) cells and do not continue oogenesis.This is the first comprehensive summary of the current knowledge on the organization and functioning of female germ-line cysts in clitellate annelids.
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Affiliation(s)
- Piotr Świątek
- Faculty of Biology and Environmental Protection, Department of Animal Histology and Embryology, University of Silesia in Katowice, Katowice, Poland.
| | - Anna Z Urbisz
- Faculty of Biology and Environmental Protection, Department of Animal Histology and Embryology, University of Silesia in Katowice, Katowice, Poland
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7
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Małota K, Student S, Świątek P. Low mitochondrial activity within developing earthworm male germ-line cysts revealed by JC-1. Mitochondrion 2018; 44:111-121. [PMID: 29398303 DOI: 10.1016/j.mito.2018.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 01/10/2018] [Accepted: 01/19/2018] [Indexed: 12/19/2022]
Abstract
The male germ-line cysts that occur in annelids appear to be a very convenient model for spermatogenesis studies. Germ-line cysts in the studied earthworm are composed of two compartments: (1) germ cells, where each cell is connected via one intercellular bridge to (2) an anuclear central cytoplasmic mass, the cytophore. In the present paper, confocal and transmission electron microscopy were used to follow the changes in the mitochondrial activity and ultrastructure within the cysts during spermatogenesis. JC-1 was used to visualize the populations of mitochondria with a high and low membrane potential. We used the spot detection Imaris software module to obtain the quantitative data. We counted and compared the 'mitochondrial spots' - the smallest detectable signals from mitochondria. It was found that in all of the stages of cyst development, the majority of mitochondria spots showed a green fluorescence, thus indicating a low mitochondrial membrane potential (MMP). Moreover, the number of active mitochondria spots that were visualized by red JC-1 fluorescence (high MMP) drastically decreased as spermatogenesis progressed. As much as 26% of the total number of mitochondrial spots in the spermatogonial cysts showed a high MMP - 19% in the spermatocytes, 24% in the isodiametric spermatids and 3% and 6%, respectively, in the cysts that were holding early and late elongate spermatids. The mitochondria were usually thread-like and had an electron-dense matrix and lamellar cristae. Then, during spermiogenesis, the mitochondria within both the spermatids and the cytophore had a tendency to form aggregates in which the mitochondria were cemented by an electron-dense material.
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Affiliation(s)
- Karol Małota
- Department of Animal Histology and Embryology, University of Silesia in Katowice, Bankowa 9, 40-007 Katowice, Poland.
| | - Sebastian Student
- Institute of Automatic Control, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland
| | - Piotr Świątek
- Department of Animal Histology and Embryology, University of Silesia in Katowice, Bankowa 9, 40-007 Katowice, Poland
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8
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Lu K, Jensen L, Lei L, Yamashita YM. Stay Connected: A Germ Cell Strategy. Trends Genet 2017; 33:971-978. [PMID: 28947158 DOI: 10.1016/j.tig.2017.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/24/2017] [Accepted: 09/05/2017] [Indexed: 01/20/2023]
Abstract
Germ cells develop as a cyst of interconnected sibling cells in a broad range of organisms in both sexes. A well-established function of intercellular connectivity is to transport cytoplasmic materials from 'nurse' cells to oocytes, a critical process for developing functional oocytes in ovaries of many species. However, there are situations where connectivity exists without a nursing mechanism, and the biological meaning of such connectivity remains obscure. In this review, we summarize current knowledge on the formation of intercellular connectivity, and discuss its meaning by visiting multiple examples of germ cell connectivity observed in evolutionarily distant species.
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Affiliation(s)
- Kevin Lu
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA; Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lindy Jensen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lei Lei
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yukiko M Yamashita
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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9
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Han Y, Zhan J, Xu Y, Zhang F, Yuan Z, Weng Q. Proliferation and apoptosis processes in the seasonal testicular development of the wild Daurian ground squirrel (Citellus dauricus Brandt, 1844). Reprod Fertil Dev 2017; 29:1680-1688. [DOI: 10.1071/rd16063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 08/15/2016] [Indexed: 01/21/2023] Open
Abstract
The aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in testicular development of wild Daurian ground squirrels during the breeding season (April), the non-breeding season (June) and before hibernation (September). Gross mass and hormonal analysis showed that the testis : body mass ratio and plasma testosterone concentration fluctuated seasonally, with a peak in April and lowest values in June. Similarly, spermatogenesis was fully developed in April but suppressed in June and September. Testicular decellularisation and vacuolisation was seen during the transition from the breeding to the non-breeding season. Furthermore, testicular levels of proliferating cell nuclear antigen, cyclin D2 and caspase-3 protein were significantly increased in June and September. Intriguingly, positive terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling staining and nuclear translocation of caspase-3 in testicular germ cells appeared only during the prehibernation period, whereas accumulation of cyclin D2 in spermatocyte nuclei occurred in September. These findings demonstrate, for the first time, that both cell proliferation and apoptosis are stimulated during the prehibernation period, indicating that a hormonal-regulated balance of testicular germ cell proliferation and apoptosis may play a pivotal role in preparing for testicular recrudescence of wild Daurian ground squirrels.
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10
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Warga RM, Wicklund A, Webster SE, Kane DA. Progressive loss of RacGAP1/ ogre activity has sequential effects on cytokinesis and zebrafish development. Dev Biol 2016; 418:307-22. [PMID: 27339293 DOI: 10.1016/j.ydbio.2016.06.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/27/2016] [Accepted: 06/16/2016] [Indexed: 12/20/2022]
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11
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Mi S, Lin M, Brouwer-Visser J, Heim J, Smotkin D, Hebert T, Gunter MJ, Goldberg GL, Zheng D, Huang GS. RNA-seq Identification of RACGAP1 as a Metastatic Driver in Uterine Carcinosarcoma. Clin Cancer Res 2016; 22:4676-86. [PMID: 27121792 DOI: 10.1158/1078-0432.ccr-15-2116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 04/04/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Uterine carcinosarcoma is a rare aggressive malignancy frequently presenting at advanced stage of disease with extrauterine metastases. Median survival is less than 2 years due to high relapse rates after surgery and poor response to chemotherapy or radiotherapy. The goal of this study was to identify novel therapeutic targets. EXPERIMENTAL DESIGN We applied RNA-seq analysis to prospectively collected uterine carcinosarcoma tumor samples from patients undergoing primary surgical resection and for comparison, normal endometrial tissues from postmenopausal women undergoing hysterectomy for benign indications. Functional assays were done in primary carcinosarcoma cell lines developed from patients and in established cell lines, as well as a cell line-derived xenograft model. Validation was done by analysis of an independent cohort of patients with uterine carcinosarcoma from The Cancer Genome Atlas (TCGA). RESULTS Rac GTPase-activating protein 1 (RACGAP1) was identified to be highly upregulated in uterine carcinosarcoma. Functional assays showed that RACGAP1 mediates motility and invasion via regulation of STAT3 phosphorylation and survivin expression. RACGAP1 depletion or survivin inhibition abrogated motility and invasiveness of carcinosarcoma cells, while RACGAP1 overexpression conferred invasiveness to endometrial adenocarcinoma cells. In the TCGA cohort, RACGAP1 expression correlated with survivin expression and extrauterine spread of disease. CONCLUSIONS The RACGAP1-STAT3-survivin signaling pathway is required for the invasive phenotype of uterine carcinosarcoma and is a newly identified therapeutic target in this lethal disease. Clin Cancer Res; 22(18); 4676-86. ©2016 AACR.
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Affiliation(s)
- Shijun Mi
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York
| | - Mingyan Lin
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York
| | - Jurriaan Brouwer-Visser
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York
| | - Jennifer Heim
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York
| | - David Smotkin
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York
| | - Tiffany Hebert
- Department of Pathology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York
| | - Marc J Gunter
- Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France
| | - Gary L Goldberg
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York. Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Deyou Zheng
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York. Departments of Neurology and Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Gloria S Huang
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York. Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York. Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York.
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12
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Analysis of the cytoskeleton organization and its possible functions in male earthworm germ-line cysts equipped with a cytophore. Cell Tissue Res 2016; 366:175-89. [PMID: 27068922 PMCID: PMC5031758 DOI: 10.1007/s00441-016-2398-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/16/2016] [Indexed: 12/12/2022]
Abstract
We studied the organization of F-actin and the microtubular cytoskeleton in male germ-line cysts in the seminal vesicles of the earthworm Dendrobaena veneta using light, fluorescent and electron microscopy along with both chemically fixed tissue and life cell imaging. Additionally, in order to follow the functioning of the cytoskeleton, we incubated the cysts in colchicine, nocodazole, cytochalasin D and latrunculin A. The male germ-line cells of D. veneta are interconnected via stable intercellular bridges (IB), and form syncytial cysts. Each germ cell has only one IB that connects it to the anuclear central cytoplasmic mass, the cytophore. During the studies, we analyzed the cytoskeleton in spermatogonial, spermatocytic and spermatid cysts. F-actin was detected in the cortical cytoplasm and forms distinct rings in the IBs. The arrangement of the microtubules changed dynamically during spermatogenesis. The microtubules are distributed evenly in whole spermatogonial and spermatocytic cysts; however, they primarily accumulate within the IBs in spermatogonia. In early spermatids, microtubules pass through the IBs and are present in whole cysts. During spermatid elongation, the microtubules form a manchette while they are absent in the cytophore and in the IBs. Use of cytoskeletal drugs did not alter the general morphology of the cysts. Detectable effects—the occurrence of nuclei in the late spermatids and manchette fragments in the cytophore—were observed only after incubation in nocodazole. Our results suggest that the microtubules are responsible for cytoplasmic/organelle transfer between the germ cells and the cytophore during spermatogenesis and for the positioning of the spermatid nuclei.
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