1
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Cui H, Culty M. Do macrophages play a role in the adverse effects of endocrine disrupting chemicals (EDCs) on testicular functions? FRONTIERS IN TOXICOLOGY 2023; 5:1242634. [PMID: 37720385 PMCID: PMC10501733 DOI: 10.3389/ftox.2023.1242634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/18/2023] [Indexed: 09/19/2023] Open
Abstract
During the past decades, several endocrine disrupting chemicals (EDCs) have been confirmed to affect male reproductive function and fertility in animal studies. EDCs are suspected to exert similar effects in humans, based on strong associations between levels of antiandrogenic EDCs in pregnant women and adverse reproductive effects in infants. Testicular macrophages (tMΦ) play a vital role in modulating immunological privilege and maintaining normal testicular homeostasis as well as fetal development. Although tMΦ were not historically studied in the context of endocrine disruption, they have emerged as potential targets to consider due to their critical role in regulating cells such as spermatogonial stem cells (SSCs) and Leydig cells. Few studies have examined the impact of EDCs on the ability of testicular cells to communicate and regulate each other's functions. In this review, we recapitulate what is known about tMΦ functions and interactions with other cell types in the testis that support spermatogenesis and steroidogenesis. We also surveyed the literature for reports on the effects of the EDCs genistein and DEHP on tMΦ, SSCs, Sertoli and Leydig cells. Our goal is to explore the possibility that EDC disruption of tMΦ interactions with other cell types may play a role in their adverse effects on testicular developmental programming and functions. This approach will highlight gaps of knowledge, which, once resolved, should improve the risk assessment of EDC exposure and the development of safeguards to protect male reproductive functions.
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Affiliation(s)
| | - Martine Culty
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, United States
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2
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Skroblyn T, Joedicke JJ, Pfau M, Krüger K, Bourquin JP, Izraeli S, Eckert C, Höpken UE. CXCR4 mediates leukemic cell migration and survival in the testicular microenvironment. J Pathol 2022; 258:12-25. [PMID: 35522562 DOI: 10.1002/path.5924] [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: 10/17/2021] [Revised: 03/30/2022] [Accepted: 05/03/2022] [Indexed: 11/11/2022]
Abstract
The testis is the second most frequent extramedullary site of relapse in pediatric acute lymphoblastic leukemia (ALL). The mechanism for B-cell (B) ALL cell migration towards and survival within the testis remains elusive. Here, we identified CXCL12-CXCR4 as the leading signaling axis for B-ALL cell migration and survival in the testicular leukemic niche. We combined analysis of primary human ALL with a novel patient-derived xenograft (PDX)-ALL mouse model with testicular involvement. Prerequisites for leukemic cell infiltration in the testis were pre-pubertal age of the recipient mice, high surface expression of CXCR4 on PDX-ALL cells, and CXCL12 secretion from the testicular stroma. Analysis of primary pediatric patient samples revealed that CXCR4 was the only chemokine receptor being robustly expressed on B-ALL cells both at the time of diagnosis and relapse. In affected patient testes, leukemic cells localized within the interstitial space in close proximity to testicular macrophages. Mouse macrophages isolated from affected testes, in the PDX model, revealed a macrophage polarization towards a M2-like phenotype in the presence of ALL cells. Therapeutically, blockade of CXCR4-mediated functions using an anti-CXCR4 antibody treatment completely abolished testicular infiltration of PDX-ALL cells and strongly impaired the overall development of leukemia. Collectively, we identified a pre-pubertal condition together with high CXCR4 expression as factors affecting the leukemia permissive testicular microenvironment. We propose CXCR4 as a promising target for therapeutic prevention of testicular relapses in childhood B-ALL. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tessa Skroblyn
- Max-Delbrück-Center for Molecular Medicine, MDC, Department of Microenvironmental Regulation in Autoimmunity and Cancer, 13125, Berlin, Germany.,Charité-University Medicine, Department of Pediatric Oncology, Campus Virchow Klinikum, 13353, Berlin, Germany
| | - Jara J Joedicke
- Max-Delbrück-Center for Molecular Medicine, MDC, Department of Translational Tumorimmunology, 13125, Berlin, Germany
| | - Madlen Pfau
- Charité-University Medicine, Department of Pediatric Oncology, Campus Virchow Klinikum, 13353, Berlin, Germany
| | - Kerstin Krüger
- Max-Delbrück-Center for Molecular Medicine, MDC, Department of Microenvironmental Regulation in Autoimmunity and Cancer, 13125, Berlin, Germany
| | - Jean P Bourquin
- Department of Pediatric Oncology, University Children's Hospital, Zurich, Switzerland
| | - Shai Izraeli
- Schneider Children's Medical Center of Israel, Petach Tiqva, and Tel Aviv University, Israel
| | - Cornelia Eckert
- Charité-University Medicine, Department of Pediatric Oncology, Campus Virchow Klinikum, 13353, Berlin, Germany.,German Cancer Consortium, and German Cancer Research Center, Im Neuenheimer Feld, Heidelberg, Germany
| | - Uta E Höpken
- Max-Delbrück-Center for Molecular Medicine, MDC, Department of Microenvironmental Regulation in Autoimmunity and Cancer, 13125, Berlin, Germany
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3
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Gaudichon J, Jakobczyk H, Debaize L, Cousin E, Galibert MD, Troadec MB, Gandemer V. Mechanisms of extramedullary relapse in acute lymphoblastic leukemia: Reconciling biological concepts and clinical issues. Blood Rev 2019; 36:40-56. [PMID: 31010660 DOI: 10.1016/j.blre.2019.04.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 04/03/2019] [Accepted: 04/15/2019] [Indexed: 12/17/2022]
Abstract
Long-term survival rates in childhood acute lymphoblastic leukemia (ALL) are currently above 85% due to huge improvements in treatment. However, 15-20% of children still experience relapses. Relapses can either occur in the bone marrow or at extramedullary sites, such as gonads or the central nervous system (CNS), formerly referred to as ALL-blast sanctuaries. The reason why ALL cells migrate to and stay in these sites is still unclear. In this review, we have attempted to assemble the evidence concerning the microenvironmental factors that could explain why ALL cells reside in such sites. We present criteria that make extramedullary leukemia niches and solid tumor metastatic niches comparable. Indeed, considering extramedullary leukemias as metastases could be a useful approach for proposing more effective treatments. In this context, we conclude with several examples of potential niche-based therapies which could be successfully added to current treatments of ALL.
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Affiliation(s)
- Jérémie Gaudichon
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France; Pediatric Hematology and Oncology Department, University Hospital, Caen, France.
| | - Hélène Jakobczyk
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France
| | - Lydie Debaize
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France
| | - Elie Cousin
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France; Pediatric Hematology Department, University Hospital, Rennes, France
| | - Marie-Dominique Galibert
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France.
| | - Marie-Bérengère Troadec
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France
| | - Virginie Gandemer
- CNRS, IGDR (Institut de Génétique et Développement de Rennes), Univ Rennes, UMR 6290, Rennes F-35000, France; Pediatric Hematology Department, University Hospital, Rennes, France.
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4
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Mayer C, Adam M, Walenta L, Schmid N, Heikelä H, Schubert K, Flenkenthaler F, Dietrich KG, Gruschka S, Arnold GJ, Fröhlich T, Schwarzer JU, Köhn FM, Strauss L, Welter H, Poutanen M, Mayerhofer A. Insights into the role of androgen receptor in human testicular peritubular cells. Andrology 2018; 6:756-765. [PMID: 29869453 DOI: 10.1111/andr.12509] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 01/07/2023]
Abstract
Contractile smooth muscle-like peritubular cells build the wall of seminiferous tubules in men. They are crucial for sperm transport and complement the functions of Sertoli cells by secreting factors, including glial cell line-derived neurotrophic factor. Previous studies revealed that they also secrete the chemokine C-X-C motif chemokine ligand 12 (CXCL12), which has known roles in spermatogenesis. Peritubular cells express the androgen receptor (AR), which is retained in isolated human testicular peritubular cells. We aimed to explore AR-regulated functions in human testicular peritubular cells. Bearing in mind that infertile men often have high aromatase activity, which may lower intratesticular androgen concentrations, an animal model for male infertility was studied. These mice display an age-dependent loss in spermatogenesis due to high aromatase activity. Human testicular peritubular cells were exposed to dihydrotestosterone or the antiandrogen flutamide. We studied AR, smooth muscle cell markers, glial cell line-derived neurotrophic factor and 15 secreted factors previously identified, including CXCL12. We used qPCR, Western blotting, ELISA or selected reaction monitoring (SRM). In the animal model for male infertility, we employed qPCR and immunohistochemistry. Dihydrotestosterone increased AR and flutamide prevented these actions. The smooth muscle cell markers calponin and smooth muscle actin were likewise increased, while cell size or cellular proliferation was not changed. Dihydrotestosterone did not increase glial cell line-derived neurotrophic factor or CXCL12 secretion but increased levels of serine proteinase inhibitor (SERPIN) E1. The animal model for male infertility with high aromatase activity showed reduced numbers of AR-immunoreactive testicular peritubular cells, suggesting that altered androgen and/or oestrogen levels could influence AR-mediated responses in peritubular cells. Androgens act on human testicular peritubular cells to enhance AR levels, their contractile phenotype and to modulate the secretion of some secreted factors. This study suggests that some aspects of human peritubular cell functions are regulated by androgens.
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Affiliation(s)
- C Mayer
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - M Adam
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany.,Turku Center for Disease Modeling and Institute of Biomedicine, University of Turku, Turku, Finland
| | - L Walenta
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - N Schmid
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - H Heikelä
- Turku Center for Disease Modeling and Institute of Biomedicine, University of Turku, Turku, Finland
| | - K Schubert
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - F Flenkenthaler
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU, Munich, Germany
| | - K-G Dietrich
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - S Gruschka
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - G J Arnold
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU, Munich, Germany
| | - T Fröhlich
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU, Munich, Germany
| | | | | | - L Strauss
- Turku Center for Disease Modeling and Institute of Biomedicine, University of Turku, Turku, Finland
| | - H Welter
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
| | - M Poutanen
- Turku Center for Disease Modeling and Institute of Biomedicine, University of Turku, Turku, Finland
| | - A Mayerhofer
- Cell Biology, Anatomy III, BMC Munich, Ludwig-Maximilians-Universität (LMU), Munich, Germany
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5
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Heckmann L, Pock T, Tröndle I, Neuhaus N. The C-X-C signalling system in the rodent vs primate testis: impact on germ cell niche interaction. Reproduction 2018; 155:R211-R219. [DOI: 10.1530/rep-17-0617] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/01/2018] [Indexed: 12/20/2022]
Abstract
In zebrafish, action of the chemokine Cxcl12 is mediated through its G-protein-coupled seven-transmembrane domain receptor Cxcr4 and the atypical receptor Cxcr7. Employing this animal model, it was revealed that this Cxcl12 signalling system plays a crucial role for directed migration of primordial germ cells (PGC) during early testicular development. Importantly, subsequent studies indicated that this regulatory mechanism is evolutionarily conserved also in mice. What is more, the functional role of the CXCL12 system does not seem to be limited to early phases of testicular development. Data from mouse studies rather demonstrate that CXCL12 and its receptors are also involved in the homing process of gonocytes into their niches at the basal membrane of the seminiferous tubules. Intriguingly, even the spermatogonial stem cells (SSCs) present in the adult mouse testis appear to maintain the ability to migrate towards a CXCL12 gradient as demonstrated by functional in vitro migration assays and in vivo germ cell transplantation assays. These findings not only indicate a role of the CXCL12 system throughout male germ cell development in mice but also suggest that this system may be evolutionarily conserved. In this review, we take into account the available literature focusing on the localization patterns of the CXCL12 system not only in rodents but also in primates, including the human. Based on these data, we discuss whether the CXCL12 system is also conserved between rodents and primates and discuss the known and potential functional consequences.
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6
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Expression patterns and role of SDF-1/CXCR4 axis in boar spermatogonial stem cells. Theriogenology 2018; 113:221-228. [PMID: 29573661 DOI: 10.1016/j.theriogenology.2018.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/09/2018] [Accepted: 03/10/2018] [Indexed: 01/01/2023]
Abstract
The signaling of chemokine stromal cell-derived factor (SDF)-1 and its receptor C-X-C motif chemokine receptor 4 (CXCR4) is involved in the cellular proliferation, survival, and migration of various cell types. Although SDF-1/CXCR4 has been implicated in the maintenance of the spermatogonial population during mouse testis development, their expression patterns and functions in boar testis remain unclear. In the present study, the expression pattern of SDF-1 and CXCR4 was determined during pre-pubertal and post-pubertal stage boar testes and in vitro cultured porcine spermatogonial stem cells (pSSCs). The role of these proteins in colony formation in cultured pSSCs was also investigated. Interestingly, SDF-1 expression was observed in PGP 9.5-positve spermatogonia in all developing stages of boar testis; however, CXCR4 expression was only detected in spermatogonia from 5-day-old boar testis. In addition, SDF-1 and CXCR4 expression was observed in cultured pSSCs from 5-day-old boar testes, and inhibition of the CXCR4 receptor signaling pathway by AMD3100 significantly decreased the colony formation of pSSCs. These results suggest that SDF-1 and CXCR4 are useful markers for detecting stage-specific spermatogonia in boar testis. Our results reveal the role of the SDF-1/CXCR4 axis in pSSC in vitro culture.
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7
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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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8
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Loveland KL, Klein B, Pueschl D, Indumathy S, Bergmann M, Loveland BE, Hedger MP, Schuppe HC. Cytokines in Male Fertility and Reproductive Pathologies: Immunoregulation and Beyond. Front Endocrinol (Lausanne) 2017; 8:307. [PMID: 29250030 PMCID: PMC5715375 DOI: 10.3389/fendo.2017.00307] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022] Open
Abstract
Germline development in vivo is dependent on the environment formed by somatic cells and the differentiation cues they provide; hence, the impact of local factors is highly relevant to the production of sperm. Knowledge of how somatic and germline cells interact is central to achieving biomedical goals relating to restoring, preserving or restricting fertility in humans. This review discusses the growing understanding of how cytokines contribute to testicular function and maintenance of male reproductive health, and to the pathologies associated with their abnormal activity in this organ. Here we consider both cytokines that signal through JAKs and are regulated by SOCS, and those utilizing other pathways, such as the MAP kinases and SMADs. The importance of cytokines in the establishment and maintenance of the testis as an immune-privilege site are described. Current research relating to the involvement of immune cells in testis development and disease is highlighted. This includes new data relating to testicular cancer which reinforce the understanding that tumorigenic cells shape their microenvironment through cytokine actions. Clinical implications in pathologies relating to local inflammation and to immunotherapies are discussed.
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Affiliation(s)
- Kate L. Loveland
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, Australia
- *Correspondence: Kate L. Loveland,
| | - Britta Klein
- Institute of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Giessen, Germany
- Institute of Anatomy and Cell Biology, Justus Liebig University Giessen, Giessen, Germany
| | - Dana Pueschl
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
- Institute of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Giessen, Germany
| | - Sivanjah Indumathy
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
- Institute of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Giessen, Germany
| | - Martin Bergmann
- Institute of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Giessen, Germany
| | | | - Mark P. Hedger
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
| | - Hans-Christian Schuppe
- Department of Urology, Pediatric Urology and Andrology, Justus Liebig University Giessen, Giessen, Germany
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Tobi M, Thomas P, Ezekwudo D. Avoiding hepatic metastasis naturally: Lessons from the cotton top tamarin (Saguinus oedipus). World J Gastroenterol 2016; 22:5479-94. [PMID: 27350726 PMCID: PMC4917608 DOI: 10.3748/wjg.v22.i24.5479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 04/26/2016] [Accepted: 05/21/2016] [Indexed: 02/06/2023] Open
Abstract
Much has been written about hepatic metastasis and animal models abound. In terms of the human experience, progress in treating this final common pathway, a terminal event of many human malignancies has been relatively slow. The current thinking is that primary prevention is best served by early detection of cancer and eradication of early stage cancers by screening. Some cancers spread early in their course and the role of screening may be limited. Until relatively recently there has not been a pathfinder model that makes the evasion of this unfortunate event a reality. This review discusses such an animal model and attempts to relate it to human disease in terms of intervention. Concrete proposals are also offered on how scientists may be able to intervene to prevent this deadly progression of the cancer process.
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Chemokine (C-X-C) Ligand 12 Facilitates Trafficking of Donor Spermatogonial Stem Cells. Stem Cells Int 2016; 2016:5796305. [PMID: 26904129 PMCID: PMC4745625 DOI: 10.1155/2016/5796305] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/29/2015] [Indexed: 12/24/2022] Open
Abstract
The chemokine (C-X-C) receptor type 4 (CXCR4) is an early marker of primordial germ cells (PGCs) essential for their migration and colonization of the gonads. In spermatogonial stem cells (SSCs), the expression of CXCR4 is promoted by the self-renewal factor, glial cell line-derived neurotrophic factor (GDNF). Here, we demonstrate an important role of CXCR4 during donor mouse SSCs reoccupation of the endogenous niche in recipient testis. Silencing of CXCR4 expression in mouse SSCs dramatically reduced the number of donor stem cell-derived colonies, whereas colony morphology and spermatogenesis were comparable to controls. Inhibition of CXCR4 signaling using a small molecule inhibitor (AMD3100) during the critical window of homing also significantly lowered the efficiency of donor-derived SSCs to establish spermatogenic colonies in recipient mice; however, the self-renewal of SSCs was not affected by exposure to AMD3100. Rather, in vitro migration assays demonstrate the influence of CXCR4-CXCL12 signaling in promoting germ cell migration. Together, these studies suggest that CXCR4-CXCL12 signaling functions to promote homing of SSCs towards the stem cell niche and plays a critical role in reestablishing spermatogenesis.
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