Oncostatin M maintains naïve pluripotency of mESCs by tetraploid embryo complementation (TEC) assay
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ABSTRACT: It has been well established that (LIF) is essential for maintaining naive pluripotency of ESCs. Oncostatin M (OSM) is a member of the IL-6 family of cytokines which share gp130 as a receptor subunit, and the OSM-gp130 complex can recruit either LIF receptor β or OSM receptor β. Here we show that OSM can completely replace LIF to maintain naive pluripotency of mouse ESCs. Mouse ESCs cultured in the presence of LIF or OSM not only express pluripotency genes at similar levels but also exhibit the same developmental pluripotency as evidenced by generation of germline competent chimeras, supporting previous findings. Moreover, we demonstrate that mESCs cultured in OSM produce viable all-ESC pups by tetraploid embryo complementation (TEC) assay, the most stringent functional test of authentic pluripotency. Furthermore, the telomere length and telomerase activity also are crucial for unlimited self-renewal and genomic stability of mESCs, and these do not differ in mESCs cultured under OSM or LIF. The transcriptome of mESCs cultured in OSM overall is very similar to that of LIF, and OSM activates Stat3 signaling pathway, like LIF. Additionally, OSM upregulates pentose and glucuronate interconversions, ascorbate and aldarate metabolism, steroid and retinol metabolism pathways. Although the significance of these pathways remains to be determined, our data shows that OSM can maintain the naive pluripotent stem cells in the absence of LIF.
Project description:Derivation of naive state of mouse embryonic stem cells (mESCs) in LIF+serum (LS) culture condition is strain dependent, whereas derivation of ground state mESCs is readily possible from all strains tested so far in “2i” culture condition. ESCs can be derived from the post-implantation stage mouse embryos (EpiSCs), showing primed characteristics. In the present study, we characterized and compared the transcriptional profile of naïve, primed and ground state mESCs. Considering the importance of genetic background of mouse model for ESCs derivation in conventional culture conditions, all ESCs lines used in the study were derived from the same strain of mice. We found distinct transcriptional profiles between naive, primed and ground state mESCs. Primed state mESCs exhibit lower expression of pluripotency markers along with higher expression of lineage specific markers compared to naive and ground state mESCs. We also demonstrate that the differentiation propensity of ESCs to specific germ layer varies depending on the pluripotency state of ESCs.
Project description:Oncostatin m (OSM) induces potent growth inhibitory and morphogenic responses in several different tumour cell types but the genetic events are not well understood. OSM can signal through two separate heterodimeric receptor complexes, gp130/LIFRα and gp130/OSMRβ. In this investigation we utilised cytokines, oncostatin M, interleukin-6 (IL-6) and leukaemia inhibitory factor (LIF) and LIF receptor antagonist, LIF-05, to help identify patterns of gene expression elicited by the different IL-6 receptor complexes in breast tumour cell line, T47D . We have tried to identify an OSM gene signature common to multiple breast tumour-derived cell lines (T47D, MCF-7 and MDA-MB-231) and identified OSM-gene regulation at time-points which coincide with the onset of OSM-induced biological effects. These findings identify a core transcriptional mechanism specific to the OSMRβ in breast tumour cells. Keywords: Comparative, timecourse, cell line-specific
Project description:Oncostatin M (OSM) and Leukemia Inhibitory Factor (LIF) signal within cells via the gp130 (Il6st) coreceptor bound either to the LIF receptor (LIFR) or the oncostatin M receptor (OSMR), but whether murine OSM can act through both receptors is controversial. Both LIF and OSM stimulate bone formation, inhibit adipocyte differentiation, and promote osteoclast differentiation, but our earlier work suggested this may depend on the receptor subtype used. This project aimed to identify those gene targets regulated by murine OSM via OSMR and LIFR by using wild type and OSMR null primary osteoblasts. Cells were differentiated to their most mature state (i.e. osteocytes) because the only prior target gene known to be regulated by murine OSM via the LIFR was an osteocyte-specific gene, sclerostin.
Project description:Activin/Nodal/TGF-β signaling pathway plays a major role in maintaining mouse epiblast stem cells (mEpiSCs). The mEpiSC medium which contains Activin A and bFGF induces differentiation of mouse embryonic stem cells (mESCs) to mEpiSC. Here we show that Activin A also has an ability to efficiently propagate mESCs without differentiation to mEpiSCs when combined with a MEK inhibitor PD0325901. mESCs cultured in Activin+PD retained high-level expression of naive pluripotency-related transcription factors. Genome-wide analysis revealed that the gene expression profile of mESCs cultured in Activin+PD resembles that of mESCs cultured in 2i. mESCs cultured in Activin+PD also showed features which are related to naive pluripotency of mESCs, including the preferential usage of the Oct4 distal enhancer and the self-renewal response to Wnt pathway activation. Our finding reveals a role of Activin/Nodal/TGF-β signaling in stabilizing self-renewal gene regulatory networks in mESCs. To compare the gene expression patterns of mESCs cultured in Activin+PD, 2i and LIF+BMP4 and mEpiSCs, we performed genome-wide gene expression analysis by using Affymetrix GeneChip oligonucleotide microarrays
Project description:The pluripotent ground state is defined as a basal state free of epigenetic restrictions, which influence lineage specification. While naive embryonic stem cells (ESCs) can be maintained in a hypomethylated state with open chromatin when grown using two small-molecule inhibitors (2i)/leukemia inhibitory factor (LIF), in contrast to serum/LIF-grown ESCs that resemble early post-implantation embryos, broader features of the ground-state pluripotent epigenome are not well understood. We identified epigenetic features of mouse ESCs cultured using 2i/LIF or serum/LIF by proteomic profiling of chromatin-associated complexes and histone modifications. Polycomb-repressive complex 2 (PRC2) and its product H3K27me3 are highly abundant in 2i/LIF ESCs, and H3K27me3 is distributed genome-wide in a CpG-dependent fashion. Consistently, PRC2-deficient ESCs showed increased DNA methylation at sites normally occupied by H3K27me3 and increased H4 acetylation. Inhibiting DNA methylation in PRC2-deficient ESCs did not affect their viability or transcriptome. Our findings suggest a unique H3K27me3 configuration protects naive ESCs from lineage priming, and they reveal widespread epigenetic crosstalk in ground-state pluripotency.
Project description:Self-renewal of embryonic stem cells (ESCs) cultured in serum-LIF is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here we purify ESCs with distinct TF expression levels from serum-LIF cultures to uncover early events during commitment from naïve pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in NANOGlow cells. Independent Esrrb reporter lines demonstrate that ESRRBnegative ESCs cannot effectively self-renew. Upon ESRRB loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in ESRRBhigh cells. Class I elements lose NANOG and OCT4 binding in ESRRBnegative ESCs and associate with genes expressed preferentially in naïve ESCs. In contrast, class II elements retain OCT4 but not NANOG binding in ESRRBnegative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from naïve pluripotency.
Project description:Self-renewal of embryonic stem cells (ESCs) cultured in serum-LIF is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here we purify ESCs with distinct TF expression levels from serum-LIF cultures to uncover early events during commitment from naïve pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in NANOGlow cells. Independent Esrrb reporter lines demonstrate that ESRRBnegative ESCs cannot effectively self-renew. Upon ESRRB loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in ESRRBhigh cells. Class I elements lose NANOG and OCT4 binding in ESRRBnegative ESCs and associate with genes expressed preferentially in naïve ESCs. In contrast, class II elements retain OCT4 but not NANOG binding in ESRRBnegative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from naïve pluripotency.
Project description:Mouse embryonic stem cells (mESCs) cultured in 2i (MEK and GSK3 kinase inhibitor)/LIF and serum/LIF that we called 2i-ESCs and serum-ESCs represent ground and confused pluripotent states, respectively. However, the transcription factors that regulate ground pluripotency through chromatin-associated characteristics are not yet fully understood. By mapping chromatin accessibility and transcription factor regulatory networks during the interconversion of 2i-ESCs and serum-ESCs, we have identified TEAD2 as highly enriched in 2i-specific peaks. While Tead2 knockout did not affect the pluripotency or differentiation ability of either 2i-ESCs or serum-ESCs, it did prevent the establishment of the 2i-specific state and the exit from the serum-specific state. TEAD2 binds to active regions in 2i-specific genes and activates their expression by regulating enhancer-promoter (EP) interactions during serum-to-2i transition. Remarkably, TEAD2-mediated EP interactions were independent of chromatin architecture proteins YY1 and CTCF, but instead appear to be facilitated by TEAD2 homodimer formation.
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:Leukemia Inhibitory Factor (LIF) plays an essential role in the maintenance of pluripotency of mouse embryonic stem cells (mESCs). LIF withdrawal induces mESC differentiation. To define noval pluripotent factors downstream of LIF signaling, cDNA microarray was used and seveal well-known pluripotent genes were found to respond to LIF withdrawal, including Klf4, Esrrb, Tbx3, and Prdm14. mESCs were cultured in presence or absence of LIF for two days and RNAs extracted from these cells were subjected to microarray analysis