Nutritional and metabolic control of germ cell fate through O-GlcNAc regulation
Ontology highlight
ABSTRACT: Fate determination of primordial germ cells (PGCs) is regulated in a multi-layered manner, involving signaling pathways, epigenetic mechanisms and transcriptional control. Epigenetic mechanisms are expected to be closely related with metabolic mechanisms but the detailed molecular machinery linking these two layers remain poorly understood. Here, we show that the hexosamine biosynthetic pathway controls PGC fate determination via O-linked -N-acetylglucosamine (O-GlcNAc) modification. Consistent with this model, reduction of carbohydrate metabolism via a maternal ketogenic diet that decreases O-GlcNAcylation levels causes repression of PGC formation in vivo. Further, the effect of maternal ketogenic diet intake until mid-gestation affected the number of ovarian germ cells in newborn pups. Taken together, we show that nutritional and metabolic mechanisms play a previously unappreciated role in PGC fate determination.
Project description:The mechanism for sex determination in mammalian germ cells remains unclear. Here, we reconstitute the female sex determination in mouse germ cells in vitro under a defined condition without the use of gonadal somatic cells. We show that retinoic acid (RA) and its key effector, STRA8, are not sufficient to induce the female germ-cell fate. In contrast, bone morphogenetic protein (BMP) and RA synergistically induce primordial germ cells (PGCs)/PGC-like cells (PGCLCs) derived from embryonic stem cells (ESCs) into fetal primary oocytes. The induction is characterized by the entry into the meiotic prophase, occurs synchronously and recapitulates cytological and transcriptome progression in vivo faithfully. Importantly, the female germ-cell induction necessitates a proper cellular competence–most typically, DNA demethylation of relevant genes–which is observed in appropriately propagated PGCs/PGCLCs, but not in PGCs/PGCLCs immediately after induction. This provides an explanation for the differential function of BMP signaling between PGC specification and female germ-cell induction. Ou findings represent a framework for a comprehensive delineation of the sex-determination pathway in mammalian germ cells, including humans.
Project description:Mammalian sexual reproduction relies on the dichotomy of male and female germ cell development. However, the underlying mechanisms remain unclear. Here, we show that ZGLP1, a conserved transcriptional regulator with GATA-like zinc fingers, determines the oogenic fate in mice. ZGLP1 acts downstream of bone morphogenetic protein (BMP), but not retinoic acid (RA), and is essential for the oogenic program and meiotic entry. ZGLP1 overexpression induces differentiation of in vitro primordial germ cell-like cells (PGCLCs) into fetal oocytes by activating the oogenic programs repressed by Polycomb activities, whereas RA signaling contributes to the oogenic program maturation and PGC program repression. Our findings elucidate the mechanism for mammalian oogenic fate determination, providing a foundation for promoting in vitro gametogenesis and reproductive medicine.
Project description:Mammalian sexual reproduction relies on the dichotomy of male and female germ cell development. However, the underlying mechanisms remain unclear. Here, we show that ZGLP1, a conserved transcriptional regulator with GATA-like zinc fingers, determines the oogenic fate in mice. ZGLP1 acts downstream of bone morphogenetic protein (BMP), but not retinoic acid (RA), and is essential for the oogenic program and meiotic entry. ZGLP1 overexpression induces differentiation of in vitro primordial germ cell-like cells (PGCLCs) into fetal oocytes by activating the oogenic programs repressed by Polycomb activities, whereas RA signaling contributes to the oogenic program maturation and PGC program repression. Our findings elucidate the mechanism for mammalian oogenic fate determination, providing a foundation for promoting in vitro gametogenesis and reproductive medicine.
Project description:A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germline is associated with primordial germ cell development and during fetal gonadal sex determination. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation primordial germ cell transcriptome and epigenome (DNA methylation) was altered transgenerationally. Interestingly, the differential DNA methylation regions (DMR) and altered transcriptomes were distinct between the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DMR and transcriptional alterations were observed in the E13 PGC than E16 germ cells. Observations demonstrate an altered transgenerational epigenetic reprogramming and function of the primordial germ cells and subsequent male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. The combined observations demonstrate ancestral exposure of a gestating female during fetal gonadal sex determination can promote transgenerational alterations in the primordial germ cell and subsequent male germline epigenetic and transcriptional programming. This altered germline programming leads to the epigenetic transgenerational inheritance of disease and phenotypic variation. Observations support the role of the primordial germ cell programming in the molecular mechanism involved and provides insights into the molecular mechanisms that control the epigenetic transgenerational inheritance phenomena. Results suggest a cascade of epigenetic and transcriptional events during germ cell development is needed to obtain the mature germline epigenome that is then transmitted transgenerationally. RNA samples from PGC of 2 F3-control lineage groups were compared to PGC of 2 F3-vinclozolin lineage groups for two embryonic age E13 and E16
Project description:Accurate specification of female and male germ cells during embryonic development is critical for sexual reproduction. Primordial germ cells (PGCs) are the bipotential precursors of mature gametes that commit to an oogenic or spermatogenic fate in response to sex-determining cues from the fetal gonad. The critical processes required for PGCs to integrate and respond to signals from the somatic environment in gonads are not understood. In this study, we developed the first single-nucleus multiomics map of chromatin accessibility and gene expression during murine PGC development in both XX and XY embryos. Profiling of cell-type specific transcriptomes and regions of open chromatin from the same cell captured the molecular signatures and gene networks underlying PGC sex determination. Joint RNA and ATAC data for single PGCs resolved previously unreported PGC subpopulations and cataloged a multimodal reference atlas of differentiating PGC clusters. We discovered that regulatory element accessibility precedes gene expression during PGC development, suggesting that changes in chromatin accessibility may prime PGC lineage commitment prior to differentiation. Similarly, we found that sexual dimorphism in chromatin accessibility and gene expression increased temporally in PGCs. Combining single-nucleus sequencing data, we computationally mapped the cohort of transcription factors that regulate the expression of sexually dimorphic genes in PGCs. For example, the gene regulatory networks of XX PGCs are enriched for the transcription factors, TFAP2c, TCFL5, GATA2, MGA, NR6A1, TBX4, and ZFX. Sex-specific enrichment of the forkhead-box and POU6 families of transcription factors was also observed in XY PGCs. Finally, we determined the temporal expression patterns of WNT, BMP, and RA signaling during PGC sex determination, and our discovery analyses identified potentially new cell communication pathways between supporting cells and PGCs. Our results illustrate the diversity of factors involved in programming PGCs towards a sex-specific fate.
Project description:Nanog, a core pluripotency factor in the inner cell mass of blastocysts, is also expressed in unipotent primordial germ cells (PGC) in mice1, where its precise role is yet unclear2-4. We investigated this in an in vitro model, where naïve pluripotent embryonic stem cells (ESCs) cultured in bFGF/ActivinA develop as epiblast-like cells (EpiLCs), and gain competence for PGC-like fate5. Consequently, bone morphogenetic protein (BMP4), or ectopic expression of key germline transcription factors Prdm1/ Prdm14/ Tfap2c, directly induce PGC-like cells (PGCLCs) in EpiLCs, but not in ESCs6-8. Here we report an unexpected discovery that Nanog alone can induce PGCLCs in EpiLCs, independently of BMP4. We propose that following the dissolution of the naïve ESC pluripotency network during establishment of EpiLCs9,10, the epigenome is reset for cell fate determination. Indeed, we found genome-wide changes in NANOG binding pattern between ESCs and EpiLCs, indicating epigenetic resetting of regulatory elements. Accordingly, we show that NANOG can bind and activate enhancers of Prdm1 and Prdm14 in EpiLCs in vitro; BLIMP1 (encoded by Prdm1) then directly induces Tfap2c. Furthermore, while SOX2 and NANOG promote the pluripotent state in ESCs, they show contrasting roles in EpiLCs since Sox2 specifically represses PGCLC induction by Nanog. This study demonstrates a broadly applicable mechanistic principle for how cells acquire competence for cell fate determination, resulting in the context-dependent roles of key transcription factors during development. Refer to individual Series
Project description:Nanog, a core pluripotency factor in the inner cell mass of blastocysts, is also expressed in unipotent primordial germ cells (PGC) in mice1, where its precise role is yet unclear2-4. We investigated this in an in vitro model, where naïve pluripotent embryonic stem cells (ESCs) cultured in bFGF/ActivinA develop as epiblast-like cells (EpiLCs), and gain competence for PGC-like fate5. Consequently, bone morphogenetic protein (BMP4), or ectopic expression of key germline transcription factors Prdm1/ Prdm14/ Tfap2c, directly induce PGC-like cells (PGCLCs) in EpiLCs, but not in ESCs6-8. Here we report an unexpected discovery that Nanog alone can induce PGCLCs in EpiLCs, independently of BMP4. We propose that following the dissolution of the naïve ESC pluripotency network during establishment of EpiLCs9,10, the epigenome is reset for cell fate determination. Indeed, we found genome-wide changes in NANOG binding pattern between ESCs and EpiLCs, indicating epigenetic resetting of regulatory elements. Accordingly, we show that NANOG can bind and activate enhancers of Prdm1 and Prdm14 in EpiLCs in vitro; BLIMP1 (encoded by Prdm1) then directly induces Tfap2c. Furthermore, while SOX2 and NANOG promote the pluripotent state in ESCs, they show contrasting roles in EpiLCs since Sox2 specifically represses PGCLC induction by Nanog. This study demonstrates a broadly applicable mechanistic principle for how cells acquire competence for cell fate determination, resulting in the context-dependent roles of key transcription factors during development. Nanog ChIP-seq
Project description:The ketogenic diet has long been used to treat epilepsy, but its mechanism is not yet clearly understood. To explore the potential mechanism, the changes in gene expression induced by the ketogenic diet in the rat kainic acid (KA) epilepsy model were analyzed. Two-condition experiment, Normal diet-fed rat brain vs. Ketogenic diet-fed rat brain. Duplicate per array
Project description:Nanog, a core pluripotency factor in the inner cell mass of blastocysts, is also expressed in unipotent primordial germ cells (PGC) in mice1, where its precise role is yet unclear2-4. We investigated this in an in vitro model, where naïve pluripotent embryonic stem cells (ESCs) cultured in bFGF/ActivinA develop as epiblast-like cells (EpiLCs), and gain competence for PGC-like fate5. Consequently, bone morphogenetic protein (BMP4), or ectopic expression of key germline transcription factors Prdm1/ Prdm14/ Tfap2c, directly induce PGC-like cells (PGCLCs) in EpiLCs, but not in ESCs6-8. Here we report an unexpected discovery that Nanog alone can induce PGCLCs in EpiLCs, independently of BMP4. We propose that following the dissolution of the naïve ESC pluripotency network during establishment of EpiLCs9,10, the epigenome is reset for cell fate determination. Indeed, we found genome-wide changes in NANOG binding pattern between ESCs and EpiLCs, indicating epigenetic resetting of regulatory elements. Accordingly, we show that NANOG can bind and activate enhancers of Prdm1 and Prdm14 in EpiLCs in vitro; BLIMP1 (encoded by Prdm1) then directly induces Tfap2c. Furthermore, while SOX2 and NANOG promote the pluripotent state in ESCs, they show contrasting roles in EpiLCs since Sox2 specifically represses PGCLC induction by Nanog. This study demonstrates a broadly applicable mechanistic principle for how cells acquire competence for cell fate determination, resulting in the context-dependent roles of key transcription factors during development. To characterize Nanog-induced Primordial Germ cell-like cells (PGCLCs), we performed expression analysis of Nanog-induced Day4 PGCLCs compared to male mouse Embryonic Stem Cells (mESCs) and male Day4 PGCLCs which were induced by cytokines. mESCs were maintained in N2B27 2i(CHIR99021 3 µM, PD0325901 1 µM) LIF(1000 U/ml) medium and Day4 PGCLCs were induced in GK15 medium with Nanog induction (0.7 µg/ml) or cytokines (BMP4 500 ng/ml, BMP8A 500 ng/ml, SCF 100 ng/ml, EGF 50 ng/ml and LIF 1000U/ml) as previously reported (Hayashi K et al., Cell, 2011).