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.
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: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.
Project description: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.