Project description: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:To investigate the molecular mechanism underlying Gp130-mediated LIF signaling in the endometrium during embryo implantation, we generated mice with uterine epithelium-specific deletion of Gp130. We report the sequencing of the uterine transcriptome of control and uterine epithelium-specific Gp130-deficient mice at day 4 (1600h) of pregnancy.
Project description:All except one cytokine of the Interleukin (IL-)6 family share glycoprotein (gp) 130 as the common b receptor chain. Whereas Interleukin (IL-)11 signal via the non-signaling IL-11 receptor (IL-11R) and gp130 homodimers, leukemia inhibitory factor (LIF) recruits gp130:LIF receptor (LIFR) heterodimers. Using IL-11 as a framework, we exchange the gp130 binding site III of IL-11 with the LIFR binding site III of LIF. The resulting synthetic cytokimera GIL-11 efficiently recruits the non-natural receptor signaling complex consisting of gp130, IL-11R and LIFR resulting in signal transduction and proliferation of factor-depending Ba/F3 cells. Besides LIF and IL-11, GIL-11 does not activate receptor complexes consisting of gp130:LIFR or gp130:IL-11R, respectively. Human GIL-11 shows cross-reactivity to mouse and rescued IL-6R deficient mice following partial hepatectomy, demonstrating gp130:IL-11R:LIFR signaling efficiently induced liver regeneration. With the development of the cytokimera GIL-11, we devise the functional assembly of the non-natural cytokine receptor complex of gp130:IL-11R:LIFR.
Project description:The pluripotency of mouse embryonic stem cells (ESC) and induced-pluripotent stem cells (iPSC) can be maintained by feeder cells, which secrete Leukemia Inhibitory Factor (LIF). We found that feeder cells provide a relatively low concentration (25 unit/ml) of LIF, which is insufficient to maintain the ESC/iPSC pluripotency in feeder free conditions. In order to identify additional factors involved in the maintenance of pluripotency, we carried out a global transcript expression profiling of mouse iPSC cultured on feeder cells and in feeder-free (LIF-treated) conditions. This identified 17 significantly differentially expressed genes (adjusted p-value<0.05) including 7 chemokines over-expressed in iPSC grown on feeder cells. Ectopic expression of these chemokines in iPSC revealed that CC chemokine ligand 2 (Ccl2) induced the key transcription factor genes for pluripotency, Klf4, Nanog, Sox2 and Tbx3. Further, addition of recombinant Ccl2 protein drastically increased the number of Nanog-GFP-positive iPSC grown in low LIF feeder free conditions. Interestingly, this effect was not observed in the absence of LIF. We further revealed that pluripotency promotion by Ccl2 is mediated by activating the Stat3-pathway followed by Klf4 up-regulation. We demonstrated that Ccl2 mediated increased pluripotency is independent of PI3K and MAPK pathways and that Tbx3 may be directly up-regulated by Klf4. Overall, Ccl2 cooperatively activates the Stat3-pathway with LIF in feeder free condition to maintain pluripotency for ESC/iPSC.
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:The pluripotency of mouse embryonic stem cells (ESC) and induced-pluripotent stem cells (iPSC) can be maintained by feeder cells, which secrete Leukemia Inhibitory Factor (LIF). We found that feeder cells provide a relatively low concentration (25 unit/ml) of LIF, which is insufficient to maintain the ESC/iPSC pluripotency in feeder free conditions. In order to identify additional factors involved in the maintenance of pluripotency, we carried out a global transcript expression profiling of mouse iPSC cultured on feeder cells and in feeder-free (LIF-treated) conditions. This identified 17 significantly differentially expressed genes (adjusted p-value<0.05) including 7 chemokines over-expressed in iPSC grown on feeder cells. Ectopic expression of these chemokines in iPSC revealed that CC chemokine ligand 2 (Ccl2) induced the key transcription factor genes for pluripotency, Klf4, Nanog, Sox2 and Tbx3. Further, addition of recombinant Ccl2 protein drastically increased the number of Nanog-GFP-positive iPSC grown in low LIF feeder free conditions. Interestingly, this effect was not observed in the absence of LIF. We further revealed that pluripotency promotion by Ccl2 is mediated by activating the Stat3-pathway followed by Klf4 up-regulation. We demonstrated that Ccl2 mediated increased pluripotency is independent of PI3K and MAPK pathways and that Tbx3 may be directly up-regulated by Klf4. Overall, Ccl2 cooperatively activates the Stat3-pathway with LIF in feeder free condition to maintain pluripotency for ESC/iPSC. Total RNAs were purified from feeder cells (as a reference sample), iPSC grown on feeder cells and iPSC grown in feeder-free condition in triplicates and applied to the arrays. iPSC grown on feeder cells were separated mechanically from the feeder layer to minimize feeder cell contamination.
Project description:Purpose: Recently discovered activating Interleukin-6 receptor subunit beta (IL6ST, encoding glycoprotein 130 (gp130)) mutations, as well as germline Signal transducer and activator of transcription 3 (STAT3) gain-of-function mutations are associated with multi-organ autoimmunity, severe morbidity, and adverse prognosis, resulting in an unmet medical need. Methods: To dissect crucial cellular subsets and disease biology involved in activated gp130 signaling, in this study we constitutively activated the gp130/JAK/STAT3 axis by means of a transgene, L-gp130, specifically targeted to T-cells. Results: Activating gp130 signaling in vivo resulted in fatal early-onset multi-organ autoimmunity, resembling numerous clinical features of human STAT3 gain-of-function disease. We observed strong T-cell activation and effector differentiation, accompanied by TH17 expansion and interferon-gamma production. Transcriptome profiling of murine CD4+ and CD8+ T-cells revealed commonly dysregulated genes and a STAT3 gain-of-function signature that was used to discriminate between STAT3 gain-of-function and healthy control patients. Conclusions: Hyperactive gp130/STAT3 signaling leads to strong TH17-mediated autoimmunity phenotypically resembling human STAT3 gain-of-function disease and identify TH17-cells as a key cellular subset for initiation and maintenance of autoimmunity
Project description:Purpose: Recently discovered activating Interleukin-6 receptor subunit beta (IL6ST, encoding glycoprotein 130 (gp130)) mutations, as well as germline Signal transducer and activator of transcription 3 (STAT3) gain-of-function mutations are associated with multi-organ autoimmunity, severe morbidity, and adverse prognosis, resulting in an unmet medical need. Methods: To dissect crucial cellular subsets and disease biology involved in activated gp130 signaling, in this study we constitutively activated the gp130/JAK/STAT3 axis by means of a transgene, L-gp130, specifically targeted to T-cells. Results: Activating gp130 signaling in vivo resulted in fatal early-onset multi-organ autoimmunity, resembling numerous clinical features of human STAT3 gain-of-function disease. On a cellular level, strong T-cell activation and effector differentiation, accompanied by TH17 expansion and interferon-gamma production was observed. Transcriptome profiling of murine CD4+ and CD8+ T-cells of Lgp and Stat3C mice revealed commonly dysregulated genes and a gene signature that allowed for discrimination between STAT3 gain-of-function patients and healthy controls. In summary, we demonstrate that hyperactive gp130/STAT3 signaling leads to TH17-driven autoimmunity, phenotypically resembling human STAT3 gain-of-function disease. Conclusions: Hyperactive gp130/STAT3 signaling leads to strong TH17-mediated autoimmunity phenotypically resembling human STAT3 gain-of-function disease and identify TH17-cells as a key cellular subset for initiation and maintenance of autoimmunity
Project description:Germline stem cells are unipotent stem cells dedicated to differentiate into gemmates throughout of life. However, spontaneous reprogramming of spermatogonial stem cells (SSCs) in long-term culture indicates the acquirement of pluripotency of germ cells affected by microenvironment.epidermal growth factor (EGF), leukemia inhibitory factor (LIF) and fresh mouse embryonic fibroblast (MEF) feeder are essential for transformation, and addition of 2i further enhanced the pluripotency. Transcriptome analysis revealed that EGF activated RAS signaling pathway and inhibited p38 to initiate transformation, and synergically cooperated with LIF to promote the transformation propensity. The increased efficiency of SSCs spontaneous reprogramming established new avenues for regenerative medicine, animal cloning, and research model for germline fate determination.
Project description:ChIP-seq to map the binding sites for CTCF and cohesin subunit Rad21 in the naive mES cells (46C cell line grown in the 2i/LIF condition) and in the neural stem cells (derived from the 46C ES cells using the mono-layer differentiation protocol, grown in the N2B27 medium these cells are Nestin+). The naive mES cells were grown in two different media (fetal bovine serum, FBS and 2i/LIF culture - naive pluripotency conditions) as detailed in the growth protocols.