Transcriptome profiling at day 30 of microRNA-mediated neuronal reprogramming [RNA-seq d30]

Neuronal microRNAs, miR-9/9* and miR-124 (miR-9/9*-124), exert reprogramming activities to direct cell-fate conversion of adult human fibroblasts to post-mitotic neurons and enable the generation of discrete neuronal subtypes with additional transcription factors. Previously, the molecular events underlying the neurogenic switch mediated by microRNAs during neuronal reprogramming were unknown. Here, we systematically dissected the neurogenic state induced by miR-9/9*-124 alone and reveal the surprising capability of miR-9/9*-124 in coordinately stimulating the reconfiguration of chromatin accessibilities, DNA methylation and transcriptome, leading to the generation of functionally excitable neurons, yet unbiased towards a particular subtype-lineage. We show that the microRNA-induced neuronal state enables additional transcription factors, ISL1 and LHX3, to selectively commit conversion to a highly homogenous population of human spinal cord motor neurons. Taken together, our study reveals a modular synergism between microRNAs and transcription factors that allows lineage-specific neuronal reprogramming, providing a platform for generating distinct subtypes of human neurons. Overall design: Human fibroblasts were reprogrammed by microRNAs miR-9/9* and miR-124 (miNs). To profile transcriptome of the reprogrammed cells, mRNA were isolated from miNs day 30 and starting fibroblasts.

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Abernathy DG, Kim WK, McCoy MJ, Lake AM, Ouwenga R, Lee SW, Xing X, Li D, Lee HJ, Heuckeroth RO, Dougherty JD, Wang T, Yoo AS