Project description:Recent advances in direct reprogramming using cell type-specific transcription factors provide an unprecedented opportunity for rapid generation of desired human cell types from easily accessible tissues. However, due to the diversity of conversion factors that facilitate the process, an arduous screening step is inevitable to find the appropriate combination(s). Here, we show that under chemically defined conditions minimal pluripotency factors are sufficient to directly reprogram human fibroblasts into stably self-renewing neural progenitor/stem cells (NSCs), but without passing through a pluripotent intermediate stage. These NSCs can be expanded and propagated in vitro without losing their potential to differentiate into various neuronal subtypes and glia. Our direct reprogramming strategy represents a simple and advanced paradigm of direct conversion that will provide an unlimited source of human neural cells for cell therapy, disease modeling, and drug screening. We used microarray to compare the global gene expression pattern between human fibroblasts and human neural epitheliums from human ESCs or directly from fibroblasts. We cultured cells and harvested them and then extracted total RNA for microarray.
Project description:Recent advances in direct reprogramming using cell type-specific transcription factors provide an unprecedented opportunity for rapid generation of desired human cell types from easily accessible tissues. However, due to the diversity of conversion factors that facilitate the process, an arduous screening step is inevitable to find the appropriate combination(s). Here, we show that under chemically defined conditions minimal pluripotency factors are sufficient to directly reprogram human fibroblasts into stably self-renewing neural progenitor/stem cells (NSCs), but without passing through a pluripotent intermediate stage. These NSCs can be expanded and propagated in vitro without losing their potential to differentiate into various neuronal subtypes and glia. Our direct reprogramming strategy represents a simple and advanced paradigm of direct conversion that will provide an unlimited source of human neural cells for cell therapy, disease modeling, and drug screening. We used microarray to compare the global gene expression pattern between human fibroblasts and human neural epitheliums from human ESCs or directly from fibroblasts.
Project description:FOXO transcription factors are central regulators of longevity from worms to humans. FOXO3 – the FOXO isoform associated with exceptional human longevity – preserves adult neural stem cell pools. Here we identify FOXO3 direct targets genome-wide in primary cultures of adult neural progenitor cells (NPCs). Interestingly, FOXO3-bound sites are enriched for motifs for bHLH transcription factors and FOXO3 shares common targets with the pro-neuronal bHLH transcription factor ASCL1/MASH1 in NPCs. Analysis of the chromatin landscape reveals that FOXO3 and ASCL1 are particularly enriched at the enhancers of genes involved in neurogenic pathways. Intriguingly, FOXO3 inhibits ASCL1-dependent neurogenesis in NPCs and direct neuronal conversion in fibroblasts. FOXO3 also restrains neurogenesis in vivo. Our study identifies a genome-wide interaction between the pro-longevity transcription factor FOXO3 and the cell fate determinant ASCL1, and raises the possibility that FOXO3’s ability to restrain ASCL1-dependent neurogenesis may help preserve the neural stem cell pool. ChIP-seq profiles of two transcription factors (FOXO3 and ASCL1) and three histone marks (H3K4me1, H3K4me3 and H3K27me3) in adult mouse neural progenitor cells.
Project description:To identify PTBP2 targets important for neural fate acqusition, miR-9/9*-124-mediated direct conversion of human fibroblasts into neurons was employed. We showed that PTBP2 is important for the successful acquisition of neuronal fate and profiled fibroblasts and reprogrammed neurons with and without PTBP2 knockdown to identify neuronal-associated PTBP2 targets during reprogramming.