Long-term expansion with germline potential of human primordial germ cell-like cells in vitro [Bisulfite-seq]
Ontology highlight
ABSTRACT: Human germ cells perpetuate human genetic and epigenetic information. However, the underlying mechanism remains elusive, due to a lack of appropriate experimental systems. Here, we show that human primordial germ cell‐like cells (hPGCLCs) derived from human‐induced pluripotent stem cells (hiPSCs) can be propagated to at least ~10^6‐fold over a period of 4 months under a defined condition in vitro. During expansion, hPGCLCs maintain an early hPGC‐like transcriptome and preserve their genome‐wide DNA methylation profiles, most likely due to retention of maintenance DNA methyltransferase activity. These characteristics contrast starkly with those of mouse PGCLCs, which, under an analogous condition, show a limited propagation (up to ~50‐fold) and persist only around 1 week, yet undergo cell‐autonomous genome‐wide DNA demethylation. Importantly, upon aggregation culture with mouse embryonic ovarian somatic cells in xenogeneic‐reconstituted ovaries, expanded hPGCLCs initiate genome‐wide DNA demethylation and differentiate into oogonia/gonocyte‐like cells, demonstrating their germline potential. By creating a paradigm for hPGCLC expansion, our study uncovers critical divergences in expansion potential and the mechanism for epigenetic reprogramming between the human and mouse germ cell lineage.
Project description:Human germ cells perpetuate human genetic and epigenetic information. However, the underlying mechanism remains elusive, due to a lack of appropriate experimental systems. Here, we show that human primordial germ cell‐like cells (hPGCLCs) derived from human‐induced pluripotent stem cells (hiPSCs) can be propagated to at least ~10^6‐fold over a period of 4 months under a defined condition in vitro. During expansion, hPGCLCs maintain an early hPGC‐like transcriptome and preserve their genome‐wide DNA methylation profiles, most likely due to retention of maintenance DNA methyltransferase activity. These characteristics contrast starkly with those of mouse PGCLCs, which, under an analogous condition, show a limited propagation (up to ~50‐fold) and persist only around 1 week, yet undergo cell‐autonomous genome‐wide DNA demethylation. Importantly, upon aggregation culture with mouse embryonic ovarian somatic cells in xenogeneic‐reconstituted ovaries, expanded hPGCLCs initiate genome‐wide DNA demethylation and differentiate into oogonia/gonocyte‐like cells, demonstrating their germline potential. By creating a paradigm for hPGCLC expansion, our study uncovers critical divergences in expansion potential and the mechanism for epigenetic reprogramming between the human and mouse germ cell lineage.
Project description:Human germ cells perpetuate human genetic and epigenetic information. However, the underlying mechanism remains elusive, due to a lack of appropriate experimental systems. Here, we show that human primordial germ cell‐like cells (hPGCLCs) derived from human‐induced pluripotent stem cells (hiPSCs) can be propagated to at least ~10^6‐fold over a period of 4 months under a defined condition in vitro. During expansion, hPGCLCs maintain an early hPGC‐like transcriptome and preserve their genome‐wide DNA methylation profiles, most likely due to retention of maintenance DNA methyltransferase activity. These characteristics contrast starkly with those of mouse PGCLCs, which, under an analogous condition, show a limited propagation (up to ~50‐fold) and persist only around 1 week, yet undergo cell‐autonomous genome‐wide DNA demethylation. Importantly, upon aggregation culture with mouse embryonic ovarian somatic cells in xenogeneic‐reconstituted ovaries, expanded hPGCLCs initiate genome‐wide DNA demethylation and differentiate into oogonia/gonocyte‐like cells, demonstrating their germline potential. By creating a paradigm for hPGCLC expansion, our study uncovers critical divergences in expansion potential and the mechanism for epigenetic reprogramming between the human and mouse germ cell lineage.
Project description:Human in vitro gametogenesis may transform reproductive medicine. Human pluripotent stem cells (hPSCs) have been induced into primordial germ cell-like cells (hPGCLCs); however, further differentiation to a mature germ cell has not been achieved. Here, we show that hPGCLCs differentiate progressively into oogonia-like cells during a long-term in vitro culture (approximately 4 months) in xenogeneic reconstituted ovaries with mouse embryonic ovarian somatic cells. The hPGCLC-derived oogonia display hallmarks of epigenetic reprogramming-genome-wide DNA demethylation, imprint erasure, and extinguishment of aberrant DNA methylation in hPSCs-and acquire an immediate precursory state for meiotic recombination. Furthermore, the inactive X chromosome shows a progressive demethylation and reactivation, albeit partially. These findings establish the germline competence of hPSCs and provide a critical step toward human in vitro gametogenesis.
Project description:The culture methods for human primordial germ cell like cells (hPGCLCs) has not been established. Here we report the culture method to expand long-term culture hPGCLCs (LTC-hPGCLCs) representing migrating morphology and early hPGC transcriptome and methylome. Key components of the culture media are stem cell factor, STO-conditioned media and absence of fetal calf serum. In this condition, these LTC-hPGCLCs were highly homogenous population without feeder cells and expanded at least 150 days. They did not express senescent phenotype such as β-galactosidase activity and shortening of telomere length at the 150-day culture, indicating that the cell might be a perpetual cell line. LTC-hPGCLCs still have potent pluripotency indicating the phenotype that the cells become human embryonic germ cells which were distinguishable from human iPS cells in strong DLK1 expression and H19 biallelic expression. In summary this simple culture method and highly homogenous LTC-hPGCLCs would be a useful resource that supports investigations on human germline cells.
Project description:The culture methods for human primordial germ cell like cells (hPGCLCs) has not been established. Here we report the culture method to expand long-term culture hPGCLCs (LTC-hPGCLCs) representing migrating morphology and early hPGC transcriptome and methylome. Key components of the culture media are stem cell factor, STO-conditioned media and absence of fetal calf serum. In this condition, these LTC-hPGCLCs were highly homogenous population without feeder cells and expanded at least 150 days. They did not express senescent phenotype such as β-galactosidase activity and shortening of telomere length at the 150-day culture, indicating that the cell might be a perpetual cell line. LTC-hPGCLCs still have potent pluripotency indicating the phenotype that the cells become human embryonic germ cells which were distinguishable from human iPS cells in strong DLK1 expression and H19 biallelic expression. In summary this simple culture method and highly homogenous LTC-hPGCLCs would be a useful resource that supports investigations on human germline cells.
Project description:The culture methods for human primordial germ cell like cells (hPGCLCs) has not been established. Here we report the culture method to expand long-term culture hPGCLCs (LTC-hPGCLCs) representing migrating morphology and early hPGC transcriptome and methylome. Key components of the culture media are stem cell factor, STO-conditioned media and absence of fetal calf serum. In this condition, these LTC-hPGCLCs were highly homogenous population without feeder cells and expanded at least 150 days. They did not express senescent phenotype such as β-galactosidase activity and shortening of telomere length at the 150-day culture, indicating that the cell might be a perpetual cell line. LTC-hPGCLCs still have potent pluripotency indicating the phenotype that the cells become human embryonic germ cells which were distinguishable from human iPS cells in strong DLK1 expression and H19 biallelic expression. In summary this simple culture method and highly homogenous LTC-hPGCLCs would be a useful resource that supports investigations on human germline cells.
Project description:Specification of primordial germ cells (PGCs) marks the beginning of the totipotent state. However, without a tractable experimental model, the mechanism of human PGC (hPGC) specification remains unclear. Here, we demonstrate specification of hPGC-like cells (hPGCLCs) from germline competent pluripotent stem cells. The characteristics of hPGCLCs are consistent with the embryonic hPGCs and a germline seminoma that share a CD38 cell-surface marker, which collectively defines likely progression of the early human germline. Remarkably, SOX17 is the key regulator of hPGC-like fate, whereas BLIMP1 represses endodermal and other somatic genes during specification of hPGCLCs. Notable mechanistic differences between mouse and human PGC specification could be attributed to their divergent embryonic development and pluripotent states, which might affect other early cell-fate decisions. We have established a foundation for future studies on resetting of the epigenome in hPGCLCs and hPGCs for totipotency and the transmission of genetic and epigenetic information. RNA-Seq analysis to investigate transcriptomes of hPGC-like cells (hPGCLCs), fetal hPGCs, TCam-2 and hESCs
Project description:Mutations in DNA damage response (DDR) factors are associated with human infertility, which affects up to 15% of the population. It remains unclear if the role of DDR is solely in meiosis. One pathway implicated in human fertility is DNA translesion synthesis (TLS), which allows replication impediments to be bypassed. We find that TLS is essential for pre-meiotic germ cell development in the embryo. Loss of the central TLS component, REV1, significantly inhibits the induction of human PGC-like cells (hPGCLCs). This is recapitulated in mice, where deficiencies in TLS initiation (Rev1-/- or PcnaK164R/K164R) or extension (Rev7-/-) result in a >150-fold reduction in the number of primordial germ cells (PGCs) and complete sterility. In contrast, the absence of TLS does not impact the growth, function, or homeostasis of somatic tissues. Surprisingly, we find a complete failure in both DNA demethylation, a critical step in germline epigenetic reprogramming, and in activation of the germ cell transcriptional program. Our findings show that for normal fertility, DNA repair is required not only for meiotic recombination but for completion of DNA demethylation and the progression of PGC development.
Project description:Epigenetic reprogramming resets parental epigenetic memories and differentiates primordial germ cells (PGCs) into mitotic pro-spermatogonia or oogonia, ensuring sexually dimorphic germ-cell development for totipotency. However, the mechanism of epigenetic reprogramming in humans remains unknown. Here, we establish a robust strategy for inducing epigenetic reprogramming and differentiation of pluripotent stem cell (PSC)-derived human PGC-like cells (hPGCLCs) into mitotic pro-spermatogonia or oogonia, coupled with their extensive amplification (~>10(10)-fold). Strikingly, bone morphogenetic protein (BMP) signaling is the key driver of these processes. Mechanistically, BMP signaling attenuates the mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) pathway and both de novo and maintenance DNA methyltransferase (DNMT) activities, promoting replication-coupled, passive DNA demethylation. On the other hand, tens-eleven translocation (TET) 1, an active DNA demethylase abundant in human germ cells, plays a dual role in hPGCLC differentiation: safeguarding hPGCLCs against differentiation into amnion-like cells by repressing key genes with bivalent promoters, and facilitating coordinated activation of genes vital for spermatogenesis and oogenesis by demethylating their promoters. Our study uncovers the principle of epigenetic reprogramming in humans, making a fundamental advance in human biology, and through the generation of abundant mitotic pro-spermatogonia and oogonia-like cells, represents a milestone for human in vitro gametogenesis (IVG) research and its potential translation into reproductive medicine.
Project description:Epigenetic reprogramming resets parental epigenetic memories and differentiates primordial germ cells (PGCs) into mitotic pro-spermatogonia or oogonia, ensuring sexually dimorphic germ-cell development for totipotency. However, the mechanism of epigenetic reprogramming in humans remains unknown. Here, we establish a robust strategy for inducing epigenetic reprogramming and differentiation of pluripotent stem cell (PSC)-derived human PGC-like cells (hPGCLCs) into mitotic pro-spermatogonia or oogonia, coupled with their extensive amplification (~>10(10)-fold). Strikingly, bone morphogenetic protein (BMP) signaling is the key driver of these processes. Mechanistically, BMP signaling attenuates the mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) pathway and both de novo and maintenance DNA methyltransferase (DNMT) activities, promoting replication-coupled, passive DNA demethylation. On the other hand, tens-eleven translocation (TET) 1, an active DNA demethylase abundant in human germ cells, plays a dual role in hPGCLC differentiation: safeguarding hPGCLCs against differentiation into amnion-like cells by repressing key genes with bivalent promoters, and facilitating coordinated activation of genes vital for spermatogenesis and oogenesis by demethylating their promoters. Our study uncovers the principle of epigenetic reprogramming in humans, making a fundamental advance in human biology, and through the generation of abundant mitotic pro-spermatogonia and oogonia-like cells, represents a milestone for human in vitro gametogenesis (IVG) research and its potential translation into reproductive medicine.