Project description:Naïve pluripotent and expanded potential stem cells (EPSCs) represent the pre-implantation epiblast which are molecularly, epigenetically and developmentally distinct from conventional primed pluripotent stem cells representing the epiblast of post-implantation embryo. These stem cell types offer expanded developmental potential towards extraembryonic tissues, clonality at the single cell level, high homogeneity and are more amenable for genome engineering. Here we use a polycistronic cassette to directly reprogram fibroblasts into induced EPSCs without a detour to primed pluripotency. When we replace SOX2 with engineered SOX17 factor (eSOX17), we obtain 7 to 10 -fold more iEPSC colonies within shorter time periods. We next tested our reprogramming regimen in four media supporting naïve pluripotency reprogramming and could reproducibly obtain large numbers of clonally expandable colonies with eSOX17 whilst SOX2 occasionally fails. The resultant naïve pluripotent and expanded potential stem cells molecularly and functionally resemble their counterparts derived from embryonic stem cells. In sum, the use of engineered SOX17 factor enables a direct, fast, efficient and reproducible reprogramming of somatic cells into cells representative of the pre-implantation epiblast from somatic cells.
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.