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Communications Biology Feb 2023Spermatogenesis is an extremely complex process, and any obstruction can cause male infertility. RhoGDIα has been identified as a risk of male sterility. In this study,...
Spermatogenesis is an extremely complex process, and any obstruction can cause male infertility. RhoGDIα has been identified as a risk of male sterility. In this study, we generate RhoGDIα knockout mice, and find that the males have severely low fertility. The testes from RhoGDIα mice are smaller than that in WT mice. The numbers of spermatogonia and spermatocytes are decreased in RhoGDIα testis. Spermatogenesis is compromised, and spermatocyte meiosis is arrested at zygotene stage in RhoGDIα mice. Acrosome dysplasia is also observed in sperms of the mutant mice. At the molecular level, RhoGDIα deficiency activate the LIMK/cofilin signaling pathway, inhibiting F-actin depolymerization, impairing testis and inducing low fertility in mouse. In addition, the treatment of RhoGDIα mice with Rac1 inhibitor NSC23766 alleviate testis injury and improve sperm quality by inhibiting the LIMK/cofilin/F-actin pathway during spermatogenesis. Together, these findings reveal a previously unrecognized RhoGDIα/Rac1/F-actin-dependent mechanism involved in spermatogenesis and male fertility.
Topics: Animals; Male; Mice; Actin Depolymerizing Factors; Actins; Infertility, Male; Mice, Knockout; rac1 GTP-Binding Protein; rho Guanine Nucleotide Dissociation Inhibitor alpha; Semen; Signal Transduction; Spermatogenesis
PubMed: 36823181
DOI: 10.1038/s42003-023-04579-7 -
Genes Apr 2021Nuclear architecture undergoes an extensive remodeling during spermatogenesis, especially at levels of spermatocytes (SPC) and spermatids (SPT). Interestingly, typical... (Review)
Review
Nuclear architecture undergoes an extensive remodeling during spermatogenesis, especially at levels of spermatocytes (SPC) and spermatids (SPT). Interestingly, typical events of spermiogenesis, such as nuclear elongation, acrosome biogenesis, and flagellum formation, need a functional cooperation between proteins of the nuclear envelope and acroplaxome/manchette structures. In addition, nuclear envelope plays a key role in chromosome distribution. In this scenario, special attention has been focused on the LINC (linker of nucleoskeleton and cytoskeleton) complex, a nuclear envelope-bridge structure involved in the connection of the nucleoskeleton to the cytoskeleton, governing mechanotransduction. It includes two integral proteins: KASH- and SUN-domain proteins, on the outer (ONM) and inner (INM) nuclear membrane, respectively. The LINC complex is involved in several functions fundamental to the correct development of sperm cells such as head formation and head to tail connection, and, therefore, it seems to be important in determining male fertility. This review provides a global overview of the main LINC complex components, with a special attention to their subcellular localization in sperm cells, their roles in the regulation of sperm morphological maturation, and, lastly, LINC complex alterations associated to male infertility.
Topics: Animals; Cell Nucleus; Cytoskeleton; Humans; Infertility, Male; Male; Mechanotransduction, Cellular; Nuclear Envelope; Nuclear Matrix; Spermatids; Spermatocytes; Spermatozoa
PubMed: 33925685
DOI: 10.3390/genes12050658 -
Reproduction in Domestic Animals =... May 2022In mammals, spermatogenesis is a complex and cyclic process in which a spermatogonia turns into a highly differentiated cell: the spermatozoa. Spermatogenesis comprises... (Review)
Review
In mammals, spermatogenesis is a complex and cyclic process in which a spermatogonia turns into a highly differentiated cell: the spermatozoa. Spermatogenesis comprises proliferation of spermatogonia (spermatocytogenesis), meiosis of spermatocytes and finally differentiation of spermatids into spermatozoa (spermiogenesis). This review summarizes the current knowledge on domestic cat spermatogenesis including its physiology, development, efficiency and pathologies as well as their novel non-invasive diagnostic methods. This information will provide a resource for further studies to achieve precise fundamental knowledge of key aspects that will facilitate breeding, management and contraception in this popular species.
Topics: Animals; Cats; Male; Mammals; Meiosis; Spermatids; Spermatocytes; Spermatogenesis; Spermatogonia; Spermatozoa; Testis
PubMed: 35098603
DOI: 10.1111/rda.14089 -
Frontiers in Cell and Developmental... 2021Meiosis is a highly conserved and essential process in gametogenesis in sexually reproducing organisms. However, there are substantial sex-specific differences within... (Review)
Review
Meiosis is a highly conserved and essential process in gametogenesis in sexually reproducing organisms. However, there are substantial sex-specific differences within individual species with respect to meiosis-related chromatin reorganization, recombination, and tolerance for meiotic defects. A wide range of murine models have been developed over the past two decades to study the complex regulatory processes governing mammalian meiosis. The present review article thus provides a comprehensive overview of the knockout mice that have been employed to study meiosis, with a particular focus on gene- and gametogenesis-related sexual dimorphism observed in these model animals. In so doing, we aim to provide a firm foundation for the future study of sex-specific differences in meiosis at the molecular level.
PubMed: 34041246
DOI: 10.3389/fcell.2021.670599 -
Current Topics in Developmental Biology 2023Successful in vitro spermatogenesis would generate functional haploid spermatids, and thus, form the basis for novel approaches to treat patients with impaired... (Review)
Review
Successful in vitro spermatogenesis would generate functional haploid spermatids, and thus, form the basis for novel approaches to treat patients with impaired spermatogenesis or develop alternative strategies for male fertility preservation. Several culture strategies, including cell cultures using various stem cells and ex vivo cultures of testicular tissue, have been investigated to recapitulate spermatogenesis in vitro. Although some studies have described complete meiosis and subsequent generation of functional spermatids, key meiotic events, such as chromosome synapsis and homologous recombination required for successful meiosis and faithful in vitro-derived gametes, are often not reported. To guarantee the generation of in vitro-formed spermatids without persistent DNA double-strand breaks (DSBs) and chromosomal aberrations, criteria to evaluate whether all meiotic events are completely executed in vitro need to be established. In vivo, these meiotic events are strictly monitored by meiotic checkpoints that eliminate aberrant spermatocytes. To establish criteria to evaluate in vitro meiosis, we review the meiotic events and checkpoints that have been investigated by previous in vitro spermatogenesis studies. We found that, although major meiotic events such as initiation of DSBs and recombination, complete chromosome synapsis, and XY-body formation can be achieved in vitro, crossover formation, chiasmata frequency, and checkpoint mechanisms have been mostly ignored. In addition, complete spermiogenesis, during which round spermatids differentiate into elongated spermatids, has not been achieved in vitro by various cell culture strategies. Finally, we discuss the implications of meiotic checkpoints for in vitro spermatogenesis protocols and future clinical use.
Topics: Humans; Male; Spermatogenesis; Spermatids; Spermatocytes; Meiosis; Sex Chromosomes
PubMed: 36681476
DOI: 10.1016/bs.ctdb.2022.04.009 -
Development (Cambridge, England) Jul 2023Valosin-containing protein (VCP) binds and extracts ubiquitylated cargo to regulate protein homeostasis. VCP has been studied primarily in aging and disease contexts,...
Valosin-containing protein (VCP) binds and extracts ubiquitylated cargo to regulate protein homeostasis. VCP has been studied primarily in aging and disease contexts, but it also affects germline development. However, the precise molecular functions of VCP in the germline, particularly in males, are poorly understood. Using the Drosophila male germline as a model system, we find that VCP translocates from the cytosol to the nucleus as germ cells transition into the meiotic spermatocyte stage. Importantly, nuclear translocation of VCP appears to be one crucial event stimulated by testis-specific TBP-associated factors (tTAFs) to drive spermatocyte differentiation. VCP promotes the expression of several tTAF-target genes, and VCP knockdown, like tTAF loss of function, causes cells to arrest in early meiotic stages. At a molecular level, VCP activity supports spermatocyte gene expression by downregulating a repressive histone modification, mono-ubiquitylated H2A (H2Aub), during meiosis. Remarkably, experimentally blocking H2Aub in VCP-RNAi testes is sufficient to overcome the meiotic-arrest phenotype and to promote development through the spermatocyte stage. Collectively, our data highlight VCP as a downstream effector of tTAFs that downregulates H2Aub to facilitate meiotic progression.
Topics: Animals; Male; Spermatocytes; Valosin Containing Protein; Cell Differentiation; Drosophila; Testis; Gene Expression; Spermatogenesis; Meiosis
PubMed: 37401420
DOI: 10.1242/dev.201557 -
Methods in Cell Biology 2021Drosophila spermatocyte centrioles are ideal for imaging studies. Their large, characteristic V conformation is both easy to identify and measure using standard imaging...
Drosophila spermatocyte centrioles are ideal for imaging studies. Their large, characteristic V conformation is both easy to identify and measure using standard imaging techniques. However, certain detailed features, such as their ninefold symmetry, are only visible below the diffraction limit of light. This is therefore a system that can benefit from the increased effective resolution potentially achievable by expansion microscopy. Here, I provide detailed protocols of two types of expansion microscopy methodologies applied to Drosophila spermatocyte centrioles, and discuss which is able to achieve the highest effective resolution in this system. I describe how to precisely measure these organelles post-expansion, and discuss how they can therefore be used as "molecular rulers" to troubleshoot and compare expansion techniques. I also provide protocols to combine expansion microscopy with super-resolution imaging in this tissue, discussing potential pitfalls. I conclude that expansion microscopy provides an effective alternative for thick tissues that are not amenable for traditional super-resolution techniques.
Topics: Animals; Centrioles; Drosophila; Male; Microscopy; Spermatocytes
PubMed: 33478691
DOI: 10.1016/bs.mcb.2020.06.008 -
Communications Biology Oct 2023Caseinolytic protease proteolytic subunit (ClpP) and caseinolytic protease X (ClpX) are mitochondrial matrix peptidases that activate mitochondrial unfolded protein...
Caseinolytic protease proteolytic subunit (ClpP) and caseinolytic protease X (ClpX) are mitochondrial matrix peptidases that activate mitochondrial unfolded protein response to maintain protein homeostasis in the mitochondria. However, the role of ClpP and ClpX in spermatogenesis remains largely unknown. In this study, we demonstrated the importance of ClpP/ClpX for meiosis and spermatogenesis with two conditional knockout (cKO) mouse models. We found that ClpP/ClpX deficiency reduced mitochondrial functions and quantity in spermatocytes, affected energy supply during meiosis and attenuated zygotene-pachytene transformation of the male germ cells. The dysregulated spermatocytes finally underwent apoptosis resulting in decreased testicular size and vacuolar structures within the seminiferous tubules. We found mTORC1 pathway was over-activated after deletion of ClpP/ClpX in spermatocytes. Long-term inhibition of the mTORC1 signaling via rapamycin treatment in vivo partially rescue spermatogenesis. The data reveal the critical roles of ClpP and ClpX in regulating meiosis and spermatogenesis.
Topics: Animals; Male; Mice; Mitochondria; Peptide Hydrolases; Serine Endopeptidases; Spermatocytes; Spermatogenesis; Endopeptidase Clp
PubMed: 37798322
DOI: 10.1038/s42003-023-05372-2 -
Andrology Jul 2023The germline perpetuates genetic information across generations. To maintain the integrity of the germline, transposable elements in the genome must be silenced, as... (Review)
Review
BACKGROUND
The germline perpetuates genetic information across generations. To maintain the integrity of the germline, transposable elements in the genome must be silenced, as these mobile elements would otherwise engender widespread mutations passed on to subsequent generations. There are several well-established mechanisms that are dedicated to providing defense against transposable elements, including DNA methylation, RNA interference, and the PIWI-interacting RNA pathway.
OBJECTIVES
Recently, several studies have provided evidence that transposon defense is not only provided by factors dedicated to this purpose but also factors with other roles, including in germline development. Many of these are transcription factors. Our objective is to summarize what is known about these "bi-functional" transcriptional regulators.
MATERIALS AND METHODS
Literature search.
RESULTS AND CONCLUSION
We summarize the evidence that six transcriptional regulators-GLIS3, MYBL1, RB1, RHOX10, SETDB1, and ZBTB16-are both developmental regulators and transposable element-defense factors. These factors act at different stages of germ cell development, including in pro-spermatogonia, spermatogonial stem cells, and spermatocytes. Collectively, the data suggest a model in which specific key transcriptional regulators have acquired multiple functions over evolutionary time to influence developmental decisions and safeguard transgenerational genetic information. It remains to be determined whether their developmental roles were primordial and their transposon defense roles were co-opted, or vice versa.
Topics: Male; Humans; DNA Transposable Elements; Gene Expression Regulation, Developmental; Spermatogonia; Transcription Factors; Spermatocytes; RNA, Small Interfering; Germ Cells
PubMed: 36895139
DOI: 10.1111/andr.13427 -
Reproduction, Fertility, and Development Nov 2023Cadherins (CDH) are crucial intercellular adhesion molecules, contributing to morphogenesis and creating tissue barriers by regulating cells' movement, clustering and... (Review)
Review
Cadherins (CDH) are crucial intercellular adhesion molecules, contributing to morphogenesis and creating tissue barriers by regulating cells' movement, clustering and differentiation. In the testis, classical cadherins such as CDH1, CDH2 and CDH3 are critical to gonadogenesis by promoting the migration and the subsequent clustering of primordial germ cells with somatic cells. While CDH2 is present in both Sertoli and germ cells in rodents, CDH1 is primarily detected in undifferentiated spermatogonia. As for CDH3, its expression is mainly found in germ and pre-Sertoli cells in developing gonads until the establishment of the blood-testis barrier (BTB). This barrier is made of Sertoli cells forming intercellular junctional complexes. The restructuring of the BTB allows the movement of early spermatocytes toward the apical compartment as they differentiate during a process called spermatogenesis. CDH2 is among many junctional proteins participating in this process and is regulated by several pathways. While cytokines promote the disassembly of the BTB by enhancing junctional protein endocytosis for degradation, testosterone facilitates the assembly of the BTB by increasing the recycling of endocytosed junctional proteins. Mitogen-activated protein kinases (MAPKs) are also mediators of the BTB kinetics in many chemically induced damages in the testis. In addition to regulating Sertoli cell functions, follicle stimulating hormone can also regulate the expression of CDH2. In this review, we discuss the current knowledge on regulatory mechanisms of cadherin localisation and expression in the testis.
Topics: Male; Animals; Testis; Cadherins; Sertoli Cells; Spermatogenesis; Spermatocytes
PubMed: 37717581
DOI: 10.1071/RD23084