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Cell Research Dec 2018Human adult spermatogenesis balances spermatogonial stem cell (SSC) self-renewal and differentiation, alongside complex germ cell-niche interactions, to ensure long-term...
Human adult spermatogenesis balances spermatogonial stem cell (SSC) self-renewal and differentiation, alongside complex germ cell-niche interactions, to ensure long-term fertility and faithful genome propagation. Here, we performed single-cell RNA sequencing of ~6500 testicular cells from young adults. We found five niche/somatic cell types (Leydig, myoid, Sertoli, endothelial, macrophage), and observed germline-niche interactions and key human-mouse differences. Spermatogenesis, including meiosis, was reconstructed computationally, revealing sequential coding, non-coding, and repeat-element transcriptional signatures. Interestingly, we identified five discrete transcriptional/developmental spermatogonial states, including a novel early SSC state, termed State 0. Epigenetic features and nascent transcription analyses suggested developmental plasticity within spermatogonial States. To understand the origin of State 0, we profiled testicular cells from infants, and identified distinct similarities between adult State 0 and infant SSCs. Overall, our datasets describe key transcriptional and epigenetic signatures of the normal adult human testis, and provide new insights into germ cell developmental transitions and plasticity.
Topics: Adolescent; Adult; Animals; Atlases as Topic; Base Sequence; Cell Cycle; Cell Plasticity; Humans; Infant; Male; Mice; Sequence Analysis, RNA; Single-Cell Analysis; Spermatogenesis; Spermatogonia; Testis; Transcriptome
PubMed: 30315278
DOI: 10.1038/s41422-018-0099-2 -
Cell Stem Cell Dec 2021Mammalian male germ-cell development consists of three distinct phases: primordial germ cell (PGC) development, male germ-cell specification for spermatogonium...
Mammalian male germ-cell development consists of three distinct phases: primordial germ cell (PGC) development, male germ-cell specification for spermatogonium development, and ensuing spermatogenesis. Here, we show an in vitro reconstitution of whole male germ-cell development by pluripotent stem cells (PSCs). Mouse embryonic stem cells (mESCs) are induced into PGC-like cells (mPGCLCs), which are expanded for epigenetic reprogramming. In reconstituted testes under an optimized condition, such mPGCLCs differentiate into spermatogonium-like cells with proper developmental transitions, gene expression, and cell-cycle dynamics and are expanded robustly as germline stem cell-like cells (GSCLCs) with an appropriate androgenetic epigenome. Importantly, GSCLCs show vigorous spermatogenesis, not only upon transplantation into testes in vivo but also under an in vitro culture of testis transplants, and the resultant spermatids contribute to fertile offspring. By uniting faithful recapitulations of the three phases of male germ-cell development, our study creates a paradigm for the in vitro male gametogenesis by PSCs.
Topics: Animals; Cell Differentiation; Epigenomics; Germ Cells; Male; Mice; Pluripotent Stem Cells; Spermatogenesis; Spermatogonia
PubMed: 34496297
DOI: 10.1016/j.stem.2021.08.005 -
Genes & Development Jun 2022Self-renewal of spermatogonial stem cells is vital to lifelong production of male gametes and thus fertility. However, the underlying mechanisms remain enigmatic. Here,...
Self-renewal of spermatogonial stem cells is vital to lifelong production of male gametes and thus fertility. However, the underlying mechanisms remain enigmatic. Here, we show that DOT1L, the sole H3K79 methyltransferase, is required for spermatogonial stem cell self-renewal. Mice lacking DOT1L fail to maintain spermatogonial stem cells, characterized by a sequential loss of germ cells from spermatogonia to spermatids and ultimately a Sertoli cell only syndrome. Inhibition of DOT1L reduces the stem cell activity after transplantation. DOT1L promotes expression of the fate-determining HoxC transcription factors in spermatogonial stem cells. Furthermore, H3K79me2 accumulates at and genes. Our findings identify an essential function for DOT1L in adult stem cells and provide an epigenetic paradigm for regulation of spermatogonial stem cells.
Topics: Animals; Cell Differentiation; Histone-Lysine N-Methyltransferase; Male; Mice; Spermatogonia; Stem Cells
PubMed: 35738678
DOI: 10.1101/gad.349550.122 -
Cell Reports Feb 2019Spermatogenesis has been intensely studied in rodents but remains poorly understood in humans. Here, we used single-cell RNA sequencing to analyze human testes....
Spermatogenesis has been intensely studied in rodents but remains poorly understood in humans. Here, we used single-cell RNA sequencing to analyze human testes. Clustering analysis of neonatal testes reveals several cell subsets, including cell populations with characteristics of primordial germ cells (PGCs) and spermatogonial stem cells (SSCs). In adult testes, we identify four undifferentiated spermatogonia (SPG) clusters, each of which expresses specific marker genes. We identify protein markers for the most primitive SPG state, allowing us to purify this likely SSC-enriched cell subset. We map the timeline of male germ cell development from PGCs through fetal germ cells to differentiating adult SPG stages. We also define somatic cell subsets in both neonatal and adult testes and trace their developmental trajectories. Our data provide a blueprint of the developing human male germline and supporting somatic cells. The PGC-like and SSC markers are candidates to be used for SSC therapy to treat infertility.
Topics: Adult; Cell Differentiation; Cells, Cultured; Humans; Infant, Newborn; Male; Single-Cell Analysis; Spermatogonia; Testis
PubMed: 30726734
DOI: 10.1016/j.celrep.2019.01.045 -
Biology of Reproduction Jul 2018Spermatogonial stem cells (SSCs) are the most primitive spermatogonia in the testis and have an essential role to maintain highly productive spermatogenesis by... (Review)
Review
Spermatogonial stem cells (SSCs) are the most primitive spermatogonia in the testis and have an essential role to maintain highly productive spermatogenesis by self-renewal and continuous generation of daughter spermatogonia that differentiate into spermatozoa, transmitting genetic information to the next generation. Since the 1950s, many experimental methods, including histology, immunostaining, whole-mount analyses, and pulse-chase labeling, had been used in attempts to identify SSCs, but without success. In 1994, a spermatogonial transplantation method was reported that established a quantitative functional assay to identify SSCs by evaluating their ability to both self-renew and differentiate to spermatozoa. The system was originally developed using mice and subsequently extended to nonrodents, including domestic animals and humans. Availability of the functional assay for SSCs has made it possible to develop culture systems for their ex vivo expansion, which dramatically advanced germ cell biology and allowed medical and agricultural applications. In coming years, SSCs will be increasingly used to understand their regulation, as well as in germline modification, including gene correction, enhancement of male fertility, and conversion of somatic cells to biologically competent male germline cells.
Topics: Adult Germline Stem Cells; Animals; Humans; Male; Spermatogenesis; Spermatogonia; Testis
PubMed: 29617903
DOI: 10.1093/biolre/ioy077 -
Stem Cell Research Dec 2017In this review, we provide an up-to-date compilation of published human spermatogonial markers, with focus on the three nuclear subtypes A, A and B. In addition, we have... (Review)
Review
In this review, we provide an up-to-date compilation of published human spermatogonial markers, with focus on the three nuclear subtypes A, A and B. In addition, we have extended our recently published list of putative spermatogonial markers with protein expression and RNA-sequencing data from the Human Protein Atlas and supported these by literature evidence. Most importantly, we have put substantial effort in acquiring a comprehensive list of new and potentially interesting markers by refiltering the raw data of 15 published germ cell expression datasets (four human, eleven rodent) and subsequent building of intersections to acquire a robust, cross-species set of spermatogonia-enriched or -specific transcripts.
Topics: Animals; Biomarkers; Humans; Male; Spermatogenesis; Spermatogonia; Testis
PubMed: 29239848
DOI: 10.1016/j.scr.2017.11.011 -
Redox Report : Communications in Free... Dec 2023: High reactive oxygen species (ROS) levels lead to cell death, and the testes are among the most vulnerable organs to oxidative damage. Rg1, an active ingredient...
: High reactive oxygen species (ROS) levels lead to cell death, and the testes are among the most vulnerable organs to oxidative damage. Rg1, an active ingredient extracted from the natural medicine ginseng, has potential anti-inflammatory, antioxidant and antiapoptotic properties. Our previous studies showed that Rg1 can effectively improve spermatogenic function in mice, but the specific mechanism remains unclear. The purpose of this study was to investigate the effect of Rg1 on oxidative stress and spermatogonium apoptosis in D-gal-induced testicular toxicity and elucidate the associated mechanism.: Male C57BL/6 mice at 6-8 weeks of age were intraperitoneally injected with D-gal (200 mg/kg) for 42 days to establish a testicular injury model, and on day 16, 40 mg/kg Rg1-rich saline was injected intraperitoneally. Concurrently, we established an in vitro model of D-gal-damaged spermatogonia, which was treated with Rg1.: We found that treatment with the ginsenoside Rg1 reduced D-gal-induced oxidative stress and spermatogonium apoptosis in vivo and in vitro. Mechanistically, we found that Rg1 activated Akt/bad signaling and reduced D-gal-induced spermatogonium apoptosis.: We provide evidence showing that the antioxidant effect of Rg1 is mediated by the Akt/GSK-3β/NRF2 axis. Based on these findings, we consider Rg1 a potential treatment for testicular oxidative damage.
Topics: Animals; Male; Mice; Antioxidants; Apoptosis; Glycogen Synthase Kinase 3 beta; Mice, Inbred C57BL; Oxidative Stress; Proto-Oncogene Proteins c-akt; Spermatogonia; Testis
PubMed: 37102430
DOI: 10.1080/13510002.2023.2206197 -
Biology of Reproduction Sep 2021More than a decade ago, the ENCODE and NIH Epigenomics Roadmap consortia organized large multilaboratory efforts to profile the epigenomes of >110 different mammalian... (Review)
Review
More than a decade ago, the ENCODE and NIH Epigenomics Roadmap consortia organized large multilaboratory efforts to profile the epigenomes of >110 different mammalian somatic cell types. This generated valuable publicly accessible datasets that are being mined to reveal genome-wide patterns of a variety of different epigenetic parameters. This consortia approach facilitated the powerful and comprehensive multiparametric integrative analysis of the epigenomes in each cell type. However, no germ cell types were included among the cell types characterized by either of these consortia. Thus, comprehensive epigenetic profiling data are not generally available for the most evolutionarily important cells, male and female germ cells. We discuss the need for reproductive biologists to generate similar multiparametric epigenomic profiling datasets for both male and female germ cells at different developmental stages and summarize our recent effort to derive such data for mammalian spermatogonial stem cells and progenitor spermatogonia.
Topics: Adult Germline Stem Cells; Animals; Cell Differentiation; Epigenesis, Genetic; Epigenome; Epigenomics; Female; Male; Mammals; Ovum; Spermatogonia; Spermatozoa
PubMed: 34250539
DOI: 10.1093/biolre/ioab135 -
Reproduction (Cambridge, England) Mar 2019Sertoli cells regulate male germ cell proliferation and differentiation and are a critical component of the spermatogonial stem cell (SSC) niche, where homeostasis is... (Review)
Review
Sertoli cells regulate male germ cell proliferation and differentiation and are a critical component of the spermatogonial stem cell (SSC) niche, where homeostasis is maintained by the interplay of several signaling pathways and growth factors. These factors are secreted by Sertoli cells located within the seminiferous epithelium, and by interstitial cells residing between the seminiferous tubules. Sertoli cells and peritubular myoid cells produce glial cell line-derived neurotrophic factor (GDNF), which binds to the RET/GFRA1 receptor complex at the surface of undifferentiated spermatogonia. GDNF is known for its ability to drive SSC self-renewal and proliferation of their direct cell progeny. Even though the effects of GDNF are well studied, our understanding of the regulation its expression is still limited. The purpose of this review is to discuss how GDNF expression in Sertoli cells is modulated within the niche, and how these mechanisms impact germ cell homeostasis.
Topics: Animals; Cell Differentiation; Cell Self Renewal; Glial Cell Line-Derived Neurotrophic Factor; Humans; Male; Sertoli Cells; Spermatogonia; Stem Cell Niche; Stem Cells
PubMed: 30620720
DOI: 10.1530/REP-18-0239 -
Trends in Genetics : TIG Oct 2021While sperm mosaicism has few consequences for men, the offspring and future generations are unwitting recipients of gonadal cell mutations, often yielding severe... (Review)
Review
While sperm mosaicism has few consequences for men, the offspring and future generations are unwitting recipients of gonadal cell mutations, often yielding severe disease. Recent studies, fueled by emergent technologies, show that sperm mosaicism is a common source of de novo mutations (DNMs) that underlie severe pediatric disease as well as human genetic diversity. Sperm mosaicism can be divided into three types: Type I arises during sperm meiosis and is non-age dependent; Type II arises in spermatogonia and increases as men age; and Type III arises during paternal embryogenesis, spreads throughout the body, and contributes stably to sperm throughout life. Where Types I and II confer little risk of recurrence, Type III may confer identifiable risk to future offspring. These mutations are likely to be the single largest contributor to human genetic diversity. New sequencing approaches may leverage this framework to evaluate and reduce disease risk for future generations.
Topics: Disease; Genomics; Humans; Male; Mosaicism; Mutation; Spermatogonia; Spermatozoa
PubMed: 34158173
DOI: 10.1016/j.tig.2021.05.007