Project description:Cardiac differentiation involves a stepwise clearance of repressors and fate-restricting regulators through the modulation of BMP/Wnt-signaling pathways. However, the mechanisms and how regulatory roadblocks are removed with specific developmental signaling pathways remain unclear. Here, we performed a genome-wide CRISPR screen to uncover essential regulators of cardiomyocyte specification in human embryonic stem cells (hESCs) and identify NF2, a Moesin-Ezrin-Radixin Like (MERLIN) Tumor Suppressor, as an upstream driver of cardiomyocyte specification. Transcriptional regulation and trajectory inference from NF2-null cells reveal the loss of cardiomyocyte identity and the acquisition of non-mesodermal identity. Sustained elevation of early mesoderm lineage repressor SOX2 and upregulation of late anti-cardiac regulators CDX2, MSX1 in NF2 knockout cells reflect a necessary role for NF2 in removing regulatory roadblocks. Since YAP is a known repressor of mesendoderm genes, we found that NF2 and AMOT cooperatively bind to YAP during mesendoderm formation, thereby preventing YAP activation independent on canonical MST-LATS1 kinase activity. Mechanistically, cardiomyocyte lineage identity was rescued by wild-type and NF2 Serine-518 phospho-mutants, but not NF2 FERM-domain blue-box mutants, showing that the critical FERM domain-dependent formation of the AMOT-NF2-YAP scaffold complex at the adherens junction is required for cardiomyocyte lineage differentiation. These results provide mechanistic insight into the essential role of NF2 for cardiomyocyte lineage specification by sequestering the repressive effect of YAP and relieving regulatory roadblocks en route to cardiomyocytes.
Project description:Gata5 efficiently promotes cardiomyocyte fate from murine ESCs.By removing serum from the culture conditions, GATA4 and GATA6 are each also able to efficiently promote cardiogenesis in ESC derivatives, with some distinctions. Thus, GATA factors can function in ESC derivatives upstream of other cardiac transcription factors to direct specification of progenitors with cardiac potential. We used microarray to compared the global gene expression of Gata5-induced cardiac cells with other growth factor directed ESC-derived cardiac cells iGata5 ESCs were induced with doxycycline at day 4 and harvested at day16 for RNA extraction and hybridization on Affymetrix microarrays.
Project description:In mammals, retinal damage is followed by Müller glia cell activation and proliferation. While retinal gliosis persists in adult mammals after an insult or disease, some vertebrates, including zebrafish, have the capacity to regenerate. We believe we are the first group to show that gliosis is a fibrotic-like process in mammals’ eyes caused by differential activation of canonical and non-canonical TGFβ signaling pathways.
Project description:Gata5 efficiently promotes cardiomyocyte fate from murine ESCs.By removing serum from the culture conditions, GATA4 and GATA6 are each also able to efficiently promote cardiogenesis in ESC derivatives, with some distinctions. Thus, GATA factors can function in ESC derivatives upstream of other cardiac transcription factors to direct specification of progenitors with cardiac potential. We used microarray to compared the global gene expression of Gata5-induced cardiac cells with other growth factor directed ESC-derived cardiac cells