Project description:We performed proteomic and phosphoproteomic profiling of cells derived from human induced pluripotent stem cells (iPSCs) using our previously described distal lung directed differentiation protocol to generate alveolar epithelial type 2 cells (iAEC2s). We used the SPC2 human iPSC line and specifically the SPC2-ST-B2 (SFTPCtdT/WT) and SPC2-ST-C11 (SFTPCI73T/tdT) clones containing a SFTPCtdTomato knock-in reporter. SFTPCtdTomato+ cells were sorted on day 41 and again on day 79 of differentiation. iAEC2s were single-cell passaged in self-renewing 3D alveolosphere cultures approximately every 2 weeks through day 113. Live SFTPCtdTomato+ iAEC2s were sorted on day 113 and processed for mass spectrometry. We find that mutant (SFTPCI73T/tdT) iAEC2s display a less proliferative and more mature AEC2 phenotype compared to their corrected (SFTPCtdT/WT) counterparts with a concomitant upregulation of lysosomal and autophagy related pathways and activation of the NF-κB pathway in mutant cells.
Project description:Foxa2 is required for endoderm differentiation into the hepatic lineage. The mechanism of activation for Foxa2 during this developmental process has not been elucidated yet. We established an in vitro system to guide ES cells differentiating into definitive endoderm (DE) cells and the following DE cells to early hepatic cells. ChIP-seq assays have been successfully performed to assess the Foxa2 binding profile. Over 50% of Foxa2 target genes in DE cells were found to be activated in hepatic cells which were at a stage later than the DE stage. Therefore, our finding at the genome-wide level proved Foxa2 serves as a pioneer factor at the DE stage. Furthermore, Foxa2 could specifically induce H3K4me2 modifications to the promoter/enhancer regions of many hepatic genes to pre-mark the chromatin, and determine the hepatic lineage differentiation competence. Our study illustrated the wide existence of Foxa2's pioneer factor function and uncovered the correlation between pioneer factor and chromatin pre-mark. These findings will be helpful for understanding the developmental process of hepatogenesis and efficiently controlling Foxa2 during hepatic induction for generating functional hepatocytes. To further gain a genome-wide view of Foxa2's effects on its target gene expression, 3 representative time points from the ES cell differentiation process to hepatic cells were selected for cDNA microarray analysis: 1) Day 0, representing ES cells, where there was no Foxa2 expression; 2) Day 5, representing DE cells; and 3) Day 7, representing early hepatic cells.
Project description:Osteogenesis is the process of bone formation and is modulated by multiple regulatory networks. With the rapid development of the epitranscriptomics field, RNA modifications and their reader, writer, and eraser (RWE) proteins are shown to be involved in the regulation of various biological processes. Few studies, however, were conducted to investigate the functions of RNA modifications and their RWE proteins in osteogenesis. By using a parallel-reaction monitoring (PRM)-based targeted proteomics method, we performed a comprehensive quantitative assessment of 154 epitranscriptomic RWE proteins during the time course of osteogenic differentiation of H9 human embryonic stem cells (ESCs). We found that approximately half of the 126 detected RWE proteins were downregulated during osteogenic differentiation, and they included mainly those proteins involved in RNA methylation and pseudouridine synthesis. Protein-protein interaction (PPI) network analysis revealed a high connectivity between the downregulated epitranscriptomic RWE proteins and osteogenesis-related proteins. Gene set enrichment analysis of previously published RNA-seq data from osteogenesis imperfecta patients suggested a potential role of METTL1, the top-ranked hub protein of downregulated RWE proteins, in osteogenesis through the cytokine network. Together, this is the first targeted profiling of epitranscriptomic RWE proteins during osteogenic differentiation of human ESCs and our work unveiled potential regulatory roles of these proteins in osteogenesis.
Project description:We performed an integrated analysis of RNA and proteins at the transition between naïve ES cells and cells primed to differentiate. During this transition, mRNAs coding for chromatin regulators were specifically released from translational inhibition mediated by RNA-Induced Silencing Complex (RISC). This suggests that, prior to differentiation, the propensity of ES cells to change their epigenetic status is hampered by RNA interference. The expression of these chromatin regulators was reinstated following acute inactivation of RISC, and it correlated with loss of stemness markers and activation of early cell differentiation markers in treated ES cells. Cytoplasmic RNA-protein complexes from mouse embryonic stem cells at different stages of neural in vitro differentiation were immunoprecipitated with anti-Argonaute antibody and analyzed by microarray hybridization
Project description:Healthy brain function is mediated by several complementary signalling pathways, many of which are driven by extracellular vesicles (EVs). EVs are heterogeneous in both size and cargo and are constitutively released from cells into the extracellular milieu. They are subsequently trafficked to recipient cells, whereupon their entry can modify the cellular phenotype. Here, in order to further understand the functional role of EVs in neurons, we isolated EVs by size exclusion chromatography from human induced pluripotent stem cell (iPSC)-derived neurons. Electron microscopy and dynamic light scattering revealed that the isolated EVs had a diameter of 30-100 nm. Transcriptomic and proteomics analyses of the EVs and neurons identified key molecules enriched in the EVs involved in cell surface interaction (integrins and collagens), internalisation pathways (clathrin- and caveolin-dependent), downstream signalling pathways (phospholipases, integrin-linked kinase and MAPKs), and long-term impacts on cellular development and maintenance. Overall, we show that key signalling networks and mechanisms are enriched in EVs isolated from human iPSC-derived neurons, and identify subpopulations of EVs defined by differential tetraspanin expression.
Project description:Previous studies have demonstrated that distinct progenitor subpopulations of mesoderm display tissue specific and vascular potential: hemangioblasts, a progenitor population capable of generating cells of the hematopoietic, endothelial and vascular smooth muscle lineages, and a multipotential progenitor capable of generating progeny of the cardiac, endothelial and vascular smooth muscle lineages. Each of these populations is characterized by co-expression of brachyury (Bry) and Flk-1, although the hemangioblast population is established before the cardiovascular progenitors in ES cell differentiation cultures (e.g. d3.5 for hemagioblast, versus d4.5 for cardiovascular progenitors). To investigate the role of Notch signalling in the establishment of cardiac lineages, we used a tet-inducible ES cell line (Ainv18) engineered to express an activated form of the Notch4 receptor following doxycycline treatment. This line also expresses a GFP cDNA from the Bry locus. Following 3.0-3.5 days of serum stimulation, three distinct populations based on Flk-1 and GFP expression are observed: Bry-GFP-/Flk-1-, Bry-GFP+/Flk-1- and Bry-GFP+/Flk-1+ cells. Previous studies have shown that the Bry-GFP+/Flk-1+ population contains hemangioblasts, whereas the Bry-GFP+/Flk-1- population displays cardiac potential. Bry-GFP+/Flk-1+ cells, sorted from EB's derived from ES cell differentiation cultures exposed to serum for 3.5 days, were allowed to reaggregate for 24 in the presence or absence of doxycycline, and the total RNA harvested at 4, 12, 24, 48, and 96 hours post Dox induction for microarray analysis. The induced populations were compared to non-induced population harvested at the same time points.
Project description:Kabuki Syndrome (KS) is a multisystemic rare disorder, characterized by growth delay, distinctive facial features, intellectual disability, and rarely autism spectrum disorder. This condition is mostly caused by de novo mutations of KMT2D, encoding a catalytic subunit of the COMPASS complex involved in enhancer regulation. KMT2D catalyzes the deposition of histone-3-lysine-4 mono-methyl (H3K4Me1) that marks active and poised enhancers. To assess the impact of KMT2D mutations in the chromatin landscape of KS tissues, we have generated patient-derived induced pluripotent stem cells (iPSC), which we further differentiated into neural crest stem cells (NCSC), mesenchymal stem cells (MSC) and cortical neurons (iN). In addition, we further collected blood samples from 5 additional KS patients. To complete our disease modeling cohort we generated an isogenic KMT2D mutant line from human embryonic stem cells, which we differentiated into neural precursor and mature neurons. Micro-electrode-array (MEA)-based neural network analysis of KS iNs revealed an altered pattern of spontaneous network-bursts in a Kabuki-specific pattern. RNA-seq profiling was performed to relate this aberrant MEA pattern to transcriptional dysregulations, revealing that dysregulated genes were enriched for neuronal functions, such as ion channels, synapse activity, and electrophysiological activity. Here we show that KMT2D haploinsufficiency tends to heavily affect the transcriptome of cortical neurons and differentiated tissues while sparing multipotent states, suggesting that KMT2D has a most prevalent role in terminally differentiated cell and activate transcriptional circuitry unique to each cell type. Moreover, thorough profiling of H3K4Me1 unveiled the almost complete uncoupling between this chromatin mark and the regulatory effects of KMT2D on transcription, which is instead reflected by a defect of H3K27Ac. By integrating RNA-seq with ChIP-seq data we defined TEAD and REST as the master effectors of KMT2D haploinsufficiency. Also, we identified a subset of genes whose regulation is controlled by the balance between KMT2D and EZH2 dosage. Finally, we identified the bona fide direct targets of KMT2D in healthy and KS mature cortical neurons and TEAD2 as the main proxy of KMT2D dysregulation in KS. Overall, our study provides the transcriptional and epigenomic characterization of patient-derived tissues as well as iPSCs and differentiated disease-relevant cell types, as well as the identification of KMT2D direct target in cortical neurons, together with the identification of a neuronal phenotype of the spontaneous electrical activity.
Project description:Determine the transcriptomic effects that are associated with the distinct differentiation phenotypes of HDAC3 knock-out vs wildtype mESCs.<br>This experiment is part of the study: "Mechanistic framework of lineage restriction in embryonic stem cells" by Olivieri et al.
Project description:QuantSeq-Rev method to generate highly strand-specific next-generation sequencing (NGS) libraries enabling transcript quantification and identification of the 3'end of polyadenylated RNAs