Project description:ELABELA (ELA) is a peptide hormone required for heart development that signals via the Apelin Receptor (APLNR, APJ). ELA is also abundantly secreted by human embryonic stem cells (hESCs), which do not express APLNR. Here we show that ELA signals in a paracrine fashion in hESCs to maintain self-renewal. ELA inhibition by CRISPR/Cas9-mediated deletion, shRNA or neutralizing antibodies causes reduced hESC growth, cell death and loss of pluripotency. Global phosphoproteomic and transcriptomic analyses of ELA-pulsed hESCs show that it activates PI3K/AKT/mTORC1 signaling required for cell survival. ELA promotes hESC cell cycle progression and protein translation, and blocks stress-induced apoptosis. INSULIN and ELA have partially overlapping functions in hESC medium, but only ELA can potentiate the TGFβ pathway to prime hESCs towards the endoderm lineage. We propose that ELA, acting through an alternate cell-surface receptor, is an endogenous secreted growth factor in human embryos and hESCs that promotes growth and pluripotency. Global Transcriptomic Analysis of INSULIN versus ELA-pulsed human embryonic stem cells was performed to elucidate the functional overlap between these two ligands
Project description:ELABELA (ELA) is a peptide hormone required for heart development that signals via the Apelin Receptor (APLNR, APJ). ELA is also abundantly secreted by human embryonic stem cells (hESCs), which do not express APLNR. Here we show that ELA signals in a paracrine fashion in hESCs to maintain self-renewal. ELA inhibition by CRISPR/Cas9-mediated deletion, shRNA or neutralizing antibodies causes reduced hESC growth, cell death and loss of pluripotency. Global phosphoproteomic and transcriptomic analyses of ELA-pulsed hESCs show that it activates PI3K/AKT/mTORC1 signaling required for cell survival. ELA promotes hESC cell cycle progression and protein translation, and blocks stress-induced apoptosis. INSULIN and ELA have partially overlapping functions in hESC medium, but only ELA can potentiate the TGFβ pathway to prime hESCs towards the endoderm lineage. We propose that ELA, acting through an alternate cell-surface receptor, is an endogenous secreted growth factor in human embryos and hESCs that promotes growth and pluripotency.
Project description:We compared a transcriptome of hESC line VUB04 which has a low differentiation propensity towards definitive endoderm with transcriptomes of control hESC lines at the undifferentiated stage and after the 24-hour differentiation towards mesendoderm. The results showed that endogenous suppression of WNT signalling in VUB04 results in an inefficient switch from self-renewal to commitment during the definitive endoderm differentiation. Subsequenlty, we demonstrated that this differentiation disruption can be overcome by increasing the WNT stimulation or by inhibiting the PI3K/AKT signalling at the onset of differentiation.
Project description:Embryonic stem (ES) cells can self-renew indefinitely without losing their differentiation ability to any cell types. Phosphoinositide-3 kinase (PI3K)/Akt signaling plays a pivotal role in various stem cell systems, including the formation of embryonic germ (EG) cells from primordial germ cells and self-renewal of neural stem cells. Here, we show that myristoylated, active form of Akt (myr-Akt) maintained the undifferentiated phenotypes in mouse ES cells without the addition of leukemia inhibitory factor (LIF). The effects of myr-Akt were reversible, because LIF dependence and pluripotent differentiation activity were restored by the deletion of myr-Akt. In addition, myr-Akt-Mer fusion protein, whose enzymatic activity is controlled by 4-hydroxy-tamoxifen, also maintained the pluripotency of not only mouse but also cynomolgus monkey ES cells. These results clearly demonstrate that Akt signaling sufficiently maintains pluripotency in mouse and primate ES cells, and support the notion that PI3K/Akt signaling axis regulates 'stemness' in a broad spectrum of stem cell systems.
Project description:Glioblastoma (GBM), classified as a grade 4 glioma, is the most prevalent intrinsic malignancy of the central nervous system. Glioblastoma stem cells (GSCs) are small populations of GBM cells with self-renewal and multilineage differentiation capabilities and are considered responsible for the tumorigenesis and development of GBM. GSCs also exhibit radiation resistance, chemoresistance, and angiogenic and invasive properties, which are correlated with poor outcomes in GBM patients. Therefore, targeting GSCs constitutes a promising approach for treating GBM patients. Our findings revealed that POSTN secreted from GSCs promotes GSC self-renewal and tumor growth via activation of the αVβ3/PI3K/AKT/β-catenin/FOSL1 pathway.
Project description:Glioblastoma (GBM), classified as a grade 4 glioma, is the most prevalent intrinsic malignancy of the central nervous system. Glioblastoma stem cells (GSCs) are small populations of GBM cells with self-renewal and multilineage differentiation capabilities and are considered responsible for the tumorigenesis and development of GBM. GSCs also exhibit radiation resistance, chemoresistance, and angiogenic and invasive properties, which are correlated with poor outcomes in GBM patients. Therefore, targeting GSCs constitutes a promising approach for treating GBM patients. Our findings revealed that POSTN secreted from GSCs promotes GSC self-renewal and tumor growth via activation of the αVβ3/PI3K/AKT/β-catenin/FOSL1 pathway.
Project description:Embryonic stem (ES) cells can self-renew indefinitely without losing their differentiation ability to any cell types. Phosphoinositide-3 kinase (PI3K)/Akt signaling plays a pivotal role in various stem cell systems, including the formation of embryonic germ (EG) cells from primordial germ cells and self-renewal of neural stem cells. Here, we show that myristoylated, active form of Akt (myr-Akt) maintained the undifferentiated phenotypes in mouse ES cells without the addition of leukemia inhibitory factor (LIF). The effects of myr-Akt were reversible, because LIF dependence and pluripotent differentiation activity were restored by the deletion of myr-Akt. In addition, myr-Akt-Mer fusion protein, whose enzymatic activity is controlled by 4-hydroxy-tamoxifen, also maintained the pluripotency of not only mouse but also cynomolgus monkey ES cells. These results clearly demonstrate that Akt signaling sufficiently maintains pluripotency in mouse and primate ES cells, and support the notion that PI3K/Akt signaling axis regulates 'stemness' in a broad spectrum of stem cell systems. Keywords: other
Project description:Long non-coding RNAs (lncRNAs) are recently characterized players that are involved in the regulatory circuitry of self-renewal in human embryonic stem cells (hESCs). However, the specific roles of lncRNAs in this circuitry are poorly understood. Here, we determined that growth-arrest-specific transcript 5 (GAS5), which is a known tumor suppressor and growth arrest gene, is abundantly expressed in the cytoplasm of hESCs and essential for hESC self-renewal. GAS5 depletion in hESCs significantly impaired their pluripotency and self-renewal ability, whereas GAS5 overexpression in hESCs accelerated the cell cycle, enhanced their colony formation ability and increased pluripotency marker expression. By RNA sequencing and bioinformatics analysis, we determined that GAS5 activates NODAL-SMAD2/3 signaling by sustaining the expression of NODAL, which plays a key role in hESC self-renewal but not in somatic cell growth. Further studies indicated that GAS5 functions as a competing endogenous RNA (ceRNA) to protect NODAL mRNA against degradation and that GAS5 transcription is directly controlled by the core pluripotency transcriptional factors (TFs). Taken together, we suggest that the core TFs, GAS5 and NODAL-SMAD2/3 form a feed-forward loop to maintain the hESC self-renewal process. These findings are specific to ESCs and did not occur in the somatic cell lines we tested; therefore, our findings also provide evidence that the functions of lncRNAs vary in different biological contexts. We analyzed long non-coding RNAs in two hESC cell lines (X-01 and H1), and found GAS5 is highly expressed and functional in maintaining hESC self-renewal. We generate stable overexpressed or knockdown hESC cell lines using lentiviral approach. We transfected cells initialy after passage, and lentiviruses are added with daily medium change for three days (at a final concentration of 10^5 IU/ml). Puromycin is added for selection and supplied with daily medium change. Stable cell lines are established after two passages and verified under fluorescence scope. Total RNAs and miRNAs are extracted separately of all three cell lines (LV-NC, LV-GAS5 and LV-shGAS5) and put to sequencing.
Project description:Collectively, our study reveals that irisin can enhance chondrogenic differentiation of hMSCs via the Rap1/PI3K/AKT pathway, suggesting that irisin possesses prospects in cartilage regeneration. Collectively, our study reveals that irisin can enhance chondrogenic differentiation of hMSCs via the Rap1/PI3K/AKT pathway, suggesting that irisin possesses prospects in cartilage regeneration.
Project description:POSTN secreted from GSCs promotes GSC self-renewal and tumor growth via activation of the αVβ3/PI3K/AKT/β-catenin/FOSL1 pathway [GSCs_RNA-seq]