Project description:Expression response after induction of putative phrenic neuronal determinants in ES cell-derived motor neurons was compared to a pre-determined list of genes over-expressed in FACS-sorted primary. Transcription factor Pou3f1 was identified as a major determinant of phrenic identity.
Project description:To develop molecular indicators of neurodevelopmental disorders related to the exposure to external chemicals, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to influence neuronal differentiation from embryonic stem cells. Thalidomide (TMD), bisphenol A (BPA), 4-hydroxy-2,2',3,4',5,5',6-heptachlorobiphenyl (4OH-PCB187) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were exposed to human embryonic stem (ES) cell-derived sphere on day 3 after starting sphere formation for 72 hours. Gene expression analysis on the stage of sphere development showed chemical specific characteristics.
Project description:Mouse embryonic stem (ES) cells cultured in defined medium with MEK and GSK3 inhibitors (2i) resemble the pre-implantation epiblast in the ground state, with full development capacity including the somatic lineages and the germline. Although β-catenin is known to be crucial for naive pluripotency of ES cells, the mechanism is not fully understood. Here we showed that β-catenin interacted with a repressive protein complex to maintain the ground state of ES cells by fine-tuning their lineage development potential. Absence of β-catenin impaired ES cell self-renewal without affecting the core self-renewal circuitry of Oct4, Sox2 and Nanog as well as other pluripotency factors. However, β-catenin-deficient cells showed a primed state transcriptional signature with perturbed expression of germline and neuronal lineage genes. Knockdown of Tcf7l1, the repressor in canonical Wnt signaling pathway, did not completely rescue the β-catenin-deficient phenotype of ES cells. Mechanistically, β-catenin formed a novel biochemical complex with E2F6, HP1γ and HMGA2 to restrain ES cells from differentiation by co-occupying the promoters of germline and neuronal lineage regulators independent of TCF7L1. Overall, out work showed that β-catenin maintained ground state ES cells by orchestrating their development plasticity through a repressive protein complex with E2F6, HP1γ and HMGA2.
Project description:Recent advances highlight the power of small molecules for promoting cellular reprogramming. Yet, the full potential of such chemicals in cell fate manipulation and the underlying mechanisms needs further characterization. Through functional screening assays, we found that mouse embryonic fibroblast can be induced to trans-differentiate into a wide range of somatic lineages simultaneously by treatment with a combination of four chemicals. Genomic analysis of the process indicates activation of multi-lineage modules and relaxation of epigenetic silencing programs. In addition, we identify Sox2 as an important regulator within the induced network. Single cell analysis uncovers a priming state that enables transition from fibroblast cells to diverse somatic lineages. Finally, we demonstrate that modification of the culture system enables directional trans-differentiation towards cardiac, neuronal or adipocytic lineages. Our study describes a cell fate control system that may be harnessed for regenerative medicine.
Project description:Expression response after induction of putative phrenic neuronal determinants in ES cell-derived motor neurons was compared to a pre-determined list of genes over-expressed in FACS-sorted primary. Transcription factor Pou3f1 was identified as a major determinant of phrenic identity. Expression in induced cell lines were compared to YFP controls, and over-representation of phrenic genes was computed for the list of differentially expressed genes in each indiced cell lines.
