Project description:We show activation of AMP kinase (AMPK) with single chemical compounds can endow naïve pluripotency. AMPK activators reverted early-stage differentiating cells or epi-stem cells to naïve state. Moreover, AMPK activators reverted human ESCs to naïve state with pluripotent gene expression profiles and X-chromosome reactivation.
Project description:We show activation of AMP kinase (AMPK) with single chemical compounds can endow naïve pluripotency. AMPK activators reverted early-stage differentiating cells or epi-stem cells to naïve state. Moreover, AMPK activators reverted human ESCs to naïve state with pluripotent gene expression profiles and X-chromosome reactivation.
Project description:Reversion from primed to naïve pluripotent status has been achieved by various signaling manipulation, but it is still unclear what signaling is the actual driving force to get over the hurdle from primed to naïve pluripotency. We previously reported that activation of AMP kinase (AMPK) contributed to maintenance of naïve pluripotency. Here, we further show that AMPK activators, AICAR, A769662 or metformin, can induce the reversion of primed mouse epiblast stem cells (mEpiSCs) to naïve pluripotent state. Primed mEpiSCs in our naïve cell culture condition with leukemia inhibitory factor (LIF) and 2 kinase inhibitors (2i) (2iL) never gave rise to naïve state cells. Addition of AICAR alone even in the absence of 2iL or either of AMPK inhibitors with LIF induced appearance of naïve-like cells from primed mEpiSCs. Through maintenance and passages of these cells in 2iL condition, clear naïve-like morphology colonies were purely obtained. They showed core naïve protein expression, and global naïve gene expression profiles. These cells contributed to chimeric mice including germline transmission. Inhibition of p38 signaling abolished the AMPK-elicited reversion and forced activation of p38 in primed mEpiSCs partially reproduced the naïve cell induction, suggesting that p38 is one of the critical downstream in AMPK activation. AMPK pathway should be a novel critical driving force in reversion of primed to naïve pluripotency.
Project description:Reversion from primed to naïve pluripotent status has been achieved by various signaling manipulation, but it is still unclear what signaling is the actual driving force to get over the hurdle from primed to naïve pluripotency. We previously reported that activation of AMP kinase (AMPK) contributed to maintenance of naïve pluripotency. Here, we further show that AMPK activators, AICAR, A769662 or metformin, can induce the reversion of primed mouse epiblast stem cells (mEpiSCs) to naïve pluripotent state. Primed mEpiSCs in our naïve cell culture condition with leukemia inhibitory factor (LIF) and 2 kinase inhibitors (2i) (2iL) never gave rise to naïve state cells. Addition of AICAR alone even in the absence of 2iL or either of AMPK inhibitors with LIF induced appearance of naïve-like cells from primed mEpiSCs. Through maintenance and passages of these cells in 2iL condition, clear naïve-like morphology colonies were purely obtained. They showed core naïve protein expression, and global naïve gene expression profiles. These cells contributed to chimeric mice including germline transmission. Inhibition of p38 signaling abolished the AMPK-elicited reversion and forced activation of p38 in primed mEpiSCs partially reproduced the naïve cell induction, suggesting that p38 is one of the critical downstream in AMPK activation. Single cell RNA-seq analysis under AICAR stimulation successfully demonstrated the reversion process with appearance of intermediate naïve-like population. AMPK pathway should be a novel critical driving force in reversion of primed to naïve pluripotency.
Project description:Although cell therapies require large numbers of quality-controlled hPSCs, existing technologies are limited in their ability to efficiently grow and scale stem cells. We report here that cell-state conversion from primed-to-naïve pluripotency enhances the biomanufacturing of hPSCs. Naïve hPSCs exhibit superior growth kinetics and aggregate formation characteristics in stirred suspension bioreactors compared to their primed counterparts. Moreover, we demonstrate the role of the bioreactor mechanical environment in the maintenance of naïve pluripotency, through transcriptomic enrichment of mechano-sensing signaling for cells in the bioreactor along with a decrease in expression of lineage-specific and primed pluripotency hallmarks. Bioreactor-cultured, naïve hPSCs express epigenetic regulatory transcripts associated with naïve pluripotency, and display hallmarks of X-chromosome reactivation. They exhibit robust production of naïve pluripotency metabolites and display reduced expression of primed pluripotency cell surface markers. We also show that these cells retain the ability to undergo targeted differentiation into beating cardiomyocytes, hepatocytes, and neural rosettes. They additionally display faster kinetics of teratoma formation compared to their primed counterparts. Naïve bioreactor hPSCs also retain structurally stable chromosomes. Our research corroborates that converting hPSCs to the naïve state enhances hPSC manufacturing and indicates a potentially important role for the bioreactor’s mechanical environment in maintaining naïve pluripotency.
Project description:The transition of pluripotent stem cells (PSCs) from primed to naïve states constitutes a prototypical example of cellular plasticity. The naïve state can be stabilized by defined chemical cocktails that block extracellular signals, notably including the MEK pathway. However, little is known regarding the underlying transcriptional mechanisms. Here, we report that the transcriptional landscape of the naïve state can be mimicked in mouse and human PSCs by stimulating transcriptional enhancers. This is attained by inhibiting the CDK8 and CDK19 kinases, which are negative regulators of Mediator, a critical component of enhancer function. Mechanistically, CDK8/19i triggers a global increase in the recruitment of RNA Pol II at promoters and enhancers, hyperactivating enhancers and their target genes. Lastly, the emergence of naïve pluripotency in the pre-implantation epiblast coincides with a marked reduction in CDK8/19 activity, and CDK8/19i blocks its subsequent developmental progression. These findings suggest that naïve pluripotency during development includes hyperactivation of enhancers and can be captured in vitro, either by blunting extracellular signaling, or by stimulating enhancer-driven transcription. These principles may apply to other cellular transitions.
Project description:Mouse embryonic stem cells (mESCs) fluctuate between a naïve inner cell mass (ICM)-like state and a primed epiblast-like state of pluripotency in serum, but are harnessed exclusively in a distinctive, apparently more naïve state of pluripotency (the ground state) with inhibitors for mitogen-activated protein kinase (MAPK) and glycogen synthase kinase 3 pathways (2i). Understanding the mechanism ensuring a naïve state of pluripotency would be critical in realizing a full potential of ESCs. We show here that PRDM14, a PR domain-containing transcriptional regulator, ensures a naïve pluripotency by a dual mechanism: Antagonizing fibroblast growth factor receptor (FGFR) signaling that is activated paradoxically by the core transcriptional circuitry for pluripotency and directs a primed state and repressing de novo DNA methyltransferases that create a primed epiblast-like epigenome. PRDM14 exerts these functions by recruiting polycomb repressive complex 2 (PRC2) specifically to key targets and repressing their expression. Mouse Embryonic Stem Cells (mESCs) or mESC-like cells with different Prdm14 genotypes {Prdm14(+/+), Prdm14(-/-), and Prdm14(-/-) rescued with Avitag-EGFP-Prdm14 transgene [Prdm14(-/-)+AGP14]} are cultured on MEF in different medium [2i, Serum(day 2), Serum+MEK inhibitor (PD0325901) (day 2), Serum without LIF (day2)].
Project description:Background: Naïve human embryonic stem cells (hESCs) have been isolated that more closely resemble the pre-implantation epiblast compared to conventional “primed” hESCs, but the signaling principles underlying these discrete stem cell states remain incompletely understood. Methods:Here we performed high-throughput screening using a library of >3,000 well-annotated compounds to identify essential signaling requirements for naïve human pluripotency. Results:We report that MEK1/2 inhibitors can be replaced during maintenance of naïve human pluripotency by inhibitors targeting either upstream (FGFR, RAF1) or downstream (ERK1/2) kinases. Naïve hESCs maintained under these alternative conditions display elevated levels of ERK phosphorylation but retain genome-wide DNA hypomethylation and a transcriptional identity of the pre-implantation epiblast. In contrast, dual inhibition of MEK and ERK promotes efficient primed-to-naïve resetting in combination with PKC, ROCK, and TNKS inhibitors and Activin A. Conclusions: This work demonstrates that induction and maintenance of naïve human pluripotency are governed by distinct signaling requirements.
Project description:Background: Naïve human embryonic stem cells (hESCs) have been isolated that more closely resemble the pre-implantation epiblast compared to conventional “primed” hESCs, but the signaling principles underlying these discrete stem cell states remain incompletely understood. Methods:Here we performed high-throughput screening using a library of >3,000 well-annotated compounds to identify essential signaling requirements for naïve human pluripotency. Results:We report that MEK1/2 inhibitors can be replaced during maintenance of naïve human pluripotency by inhibitors targeting either upstream (FGFR, RAF1) or downstream (ERK1/2) kinases. Naïve hESCs maintained under these alternative conditions display elevated levels of ERK phosphorylation but retain genome-wide DNA hypomethylation and a transcriptional identity of the pre-implantation epiblast. In contrast, dual inhibition of MEK and ERK promotes efficient primed-to-naïve resetting in combination with PKC, ROCK, and TNKS inhibitors and Activin A. Conclusions: This work demonstrates that induction and maintenance of naïve human pluripotency are governed by distinct signaling requirements.
Project description:It is now well recognized that human embryonic stem cells (hESCs)1 closely resemble mouse epiblast stem cells (mEpiSCs)2-5 exhibiting primed pluripotency unlike mouse ESCs (mESCs) which acquire a naïve pluripotent state4-8. Efforts have been made to trigger naïve pluripotency in hESCs9-11 for subsequent unbiased lineage-specific differentiation, a common conundrum faced by primed pluripotent hESCs due to heterogeneity in gene expression existing within and between hESC lines12. We report here a novel culture medium facilitating rapid induction of naïve pluripotency in established hESCs. Our medium also allows derivation of naïve mESCs from blastocyst stage which has not been shown earlier. The established naïve hESCs could survive long-term single cell passaging, maintain a normal karyotype, exhibit upregulation of naïve pluripotency genes and were dependent on signaling pathways similar to naïve mESCs. Also, they undergo global DNA demethylation, cluster together with previously described naïve hESCs13 and show a distinctive long non-coding RNA profile. Collectively, we demonstrate an alternate route to capture naïve pluripotency in hESCs which is fast, reproducible, can be employed to derive naïve mESCs and can induce efficient differentiation. Three primed and matching naive human embryonic stem cell lines were profiled in duplo.