A Molecular Roadmap of the Phased Progression of Pluripotency
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ABSTRACT: Pluripotency is highly dynamic and progresses through a continuum of pluripotent stem cell states. The two states that bookend the pluripotency continuum, naïve and primed, are well characterized, but our understanding of the intermediate states and the transitions between them remain incomplete. To address this gap in knowledge, using a previously validated system to induce naive mouse embryonic stem cells (ESCs) to post-implantation pre-grastrulating epiblast-like cells (EpiLCs), we generated comprehensive high-temporal-resolution maps of the proteome, phosphoproteome, transcriptome, and epigenome of ESCs transitioning from naïve to primed pluripotency. Our data provide a comprehensive molecular description of the phased progression of pluripotency and a foundation for investigating mechanisms that regulate pluripotent state transitions.
Project description:Pluripotency is highly dynamic and progresses through a continuum of pluripotent stem-cell states. The two states that bookend the pluripotency continuum, naïve and primed, are well characterized, but our understanding of the intermediate states and transitions between them remain incomplete. Here, we dissect the dynamics of pluripotent state transitions underlying pre- to post-implantation epiblast differentiation. Through comprehensive mapping of the proteome, phosphoproteome, transcriptome, and epigenome of embryonic stem cells transitioning from naïve to primed pluripotency, we find that rapid, acute, and widespread changes to the phosphoproteome precede ordered changes to the epigenome, transcriptome, and proteome. Reconstruction of kinase-substrate networks reveals signaling cascades, dynamics, and crosstalk. Distinct waves of global proteomic changes mark discrete phases of pluripotency, with cell state-specific surface markers tracking pluripotent state transitions. Our data provide new insights into the multi-layered control of the phased progression of pluripotency and a foundation for modeling mechanisms regulating pluripotent state transitions (www.stemcellatlasorg).
Project description:Pluripotent Embryonic Stem Cells (ESCs) can be captured in vitro in different states, ranging from unrestricted ‘naïve’ to more developmentally constrained ‘primed’ pluripotency. Complexes involved in epigenetic regulation and key transcription factors have been shown to be involved in specifying these distinct states. In this study, we use proteomic profiling of the chromatin landscape in naive pluripotent ESCs, Epistem cells (EpiSCs) and early differentiated ESCs to survey the chromatin in naïve and primed pluripotency and during differentiation. We provide a comprehensive overview of epigenetic complexes situated on the chromatin and identify proteins associated with the maintenance and loss of pluripotency. The findings presented here indicate major compositional alterations of epigenetic complexes starting from ESC priming onwards. Our results contribute to the understanding of ESC differentiation and provide a framework for future studies of lineage commitment of ESCs.
Project description:Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here, we identify Mettl3, an N6-methyladenosine (m6A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout pre-implantation epiblasts and naïve embryonic stem cells (ESCs) are depleted for m6A in mRNAs and yet, are viable. However, they fail to adequately terminate their naïve state, and subsequently undergo aberrant and restricted lineage priming at the post-implantation stage, leading to early embryonic lethality. m6A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo, and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.
Project description:Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here we identify Mettl3, an N6-Methyladenosine (m6A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout pre-implantation epiblasts and naïve embryonic stem cells (ESCs) are depleted for m6A in mRNAs and yet, are viable. However, they fail to adequately terminate their naïve state, and subsequently undergo aberrant and restricted lineage priming at the post-implantation stage, leading to early embryonic lethality. m6A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo, and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.
Project description:Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here we identify Mettl3, an N6-Methyladenosine (m6A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout pre-implantation epiblasts and naïve embryonic stem cells (ESCs) are depleted for m6A in mRNAs and yet, are viable. However, they fail to adequately terminate their naïve state, and subsequently undergo aberrant and restricted lineage priming at the post-implantation stage, leading to early embryonic lethality. m6A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo, and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.
Project description:Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here we identify Mettl3, an N6-Methyladenosine (m6A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout pre-implantation epiblasts and naïve embryonic stem cells (ESCs) are depleted for m6A in mRNAs and yet, are viable. However, they fail to adequately terminate their naïve state, and subsequently undergo aberrant and restricted lineage priming at the post-implantation stage, leading to early embryonic lethality. m6A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo, and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.
Project description:In this study we identify Mettl3, an m6A RNA modification writer, as a critical regulator for terminating naïve pluripotency and a positive maintainer of primed pluripotency in vitro and in vivo. Remarkably, Mettl3 knockout pre-implantation epiblasts and naïve ES cells, entirely lack m6A on coding mRNAs and are viable. Yet, they fail to adequately terminate the naïve pluripotent state, and subsequently undergo aberrant priming and early lineage commitment at the post-implantation stage. A comprehensive functional and genomic analysis involving profiling of m6A, RNA transcription and translation in Mettl3 wild-type and knockout pluripotent and differentiated cells, identified m6A as a critical determinant that destabilizes secondary naïve specific pluripotency genes Esrrb, Klf4 and Nanog, and restrains their transcript stability and translation efficiency. In summary, our findings provide for the first time evidence for a critical role for an mRNA epigenetic modification in early mammalian development in vivo, and identify a mechanism that functionally regulates mouse naïve and primed pluripotency in an opposing manner. polyA RNA-seq was measured in mouse embryonic stem cells (ESCs) and embroid bodies (EBs), each in WT and in Mettl3-KO cell lines. RNA-seq was measured also from WT mouse embronic fibroblasts (MEF). 3 biological replicates are available from ESCs and 2 from EBs. Replicate C in ESCs was measured alongside protein levels (SILAC) and was used for the analysis of that assay.
Project description:Naïve and primed pluripotency is characterized by distinct signaling requirements, transcriptomes and developmental properties, but both cellular states share key transcriptional regulators, Oct4, Sox2 and Nanog. Here we demonstrate that transition between these two pluripotent states is associated with widespread Oct4 relocalization, mirrored by global rearrangement of enhancer chromatin landscapes. Our genomic and biochemical analyses identified candidate mediators of primed state-specific Oct4 binding, including Otx2 and Zic2/3. Even in the absence of other differentiation cues, premature Otx2 overexpression is sufficient to exit the naïve state, induce transcription of a large subset of primed pluripotency-associated genes and redirect Oct4 to thousands of previously inaccessible sites. However, ability of Otx2 to engage new enhancer regions is determined by its levels, cis-encoded properties of the sites and signaling environment. Our results illuminate regulatory mechanisms underlying pluripotency and suggest that capacity of transcription factors such as Otx2 and Oct4 to function as pioneers is highly context-dependent transcription profile of ESCs and EpiLCs to analzye changes during differentiation and the effect of Otx2 loss and overexpression on the differentiation properties
Project description:Pluripotent cell identity comprises a spectrum of cell states including naive and primed states, which are typified by mouse embryonic stem cells (ESCs) and epiblast-derived stem cells (EpiSCs), respectively. Here we define a pluripotent cell fate (PCF) gene signature based on RNA-seq analysis associated with naive and primed pluripotency acquisition, and identify Zfp281 as a key transcriptional regulator for primed pluripotency and also as a barrier to achieve the naive pluripotency of both mouse and human ESCs. RNA sequencing analysis was performed in WT and Zfp281 null mouse embryonic stem cells under different pluripotent culture conditions. RNA-seq Experiments were carry out in two biological replciates. Genome binding/occupancy profiling of Zfp281 was performed in mouse embryonic stem cells by ChIP sequencing.
Project description:Pluripotent cell identity comprises a spectrum of cell states including naive and primed states, which are typified by mouse embryonic stem cells (ESCs) and epiblast-derived stem cells (EpiSCs), respectively. Here we define a pluripotent cell fate (PCF) gene signature based on RNA-seq analysis associated with naive and primed pluripotency acquisition, and identify Zfp281 as a key transcriptional regulator for primed pluripotency and also as a barrier to achieve the naive pluripotency of both mouse and human ESCs. RNA sequencing analysis was performed in WT and Zfp281 null mouse embryonic stem cells under different pluripotent culture conditions. RNA-seq Experiments were carry out in two biological replciates. Genome binding/occupancy profiling of Zfp281 was performed in mouse embryonic stem cells by ChIP sequencing.