MicroRNAs Induce a Permissive Chromatin Environment that Enables Neuronal Subtype-Specific Reprogramming of Adult Human Fibroblasts

• Published in: Cell stem cell Vol. 21; no. 3; pp. 332 - 348.e9
• Main Authors: Abernathy, Daniel G., Kim, Woo Kyung, McCoy, Matthew J., Lake, Allison M., Ouwenga, Rebecca, Lee, Seong Won, Xing, Xiaoyun, Li, Daofeng, Lee, Hyung Joo, Heuckeroth, Robert O., Dougherty, Joseph D., Wang, Ting, Yoo, Andrew S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 07.09.2017
• Subjects: Adult; cell fate; Cell Lineage - genetics; Cells, Cultured; Cellular Reprogramming - genetics; Chromatin - metabolism; chromatin accessibility; Chromatin Assembly and Disassembly - genetics; chromatin remodeling; direct reprogramming; DNA methylation; DNA Methylation - genetics; Electrophysiological Phenomena; Epigenesis, Genetic; epigenetics; Fibroblasts - cytology; Gene Expression Profiling; Heterochromatin - metabolism; human neurons; Humans; microRNA; MicroRNAs - genetics; MicroRNAs - metabolism; motor neurons; Motor Neurons - cytology; Motor Neurons - metabolism; neurogenesis; Neurogenesis - genetics; Neurons - cytology; Neurons - metabolism; Spinal Cord - cytology; Time Factors; Transcription, Genetic; Transcriptional Activation - genetics; motor neurons; human neurons; direct reprogramming; cell fate; chromatin accessibility; chromatin remodeling; DNA methylation; neurogenesis; microRNA; epigenetics
• ISSN: 1934-5909; 1875-9777
• DOI: 10.1016/j.stem.2017.08.002

Directed reprogramming of human fibroblasts into fully differentiated neurons requires massive changes in epigenetic and transcriptional states. Induction of a chromatin environment permissive for acquiring neuronal subtype identity is therefore a major barrier to fate conversion. Here we show that the brain-enriched miRNAs miR-9/9∗ and miR-124 (miR-9/9∗-124) trigger reconfiguration of chromatin accessibility, DNA methylation, and mRNA expression to induce a default neuronal state. miR-9/9∗-124-induced neurons (miNs) are functionally excitable and uncommitted toward specific subtypes but possess open chromatin at neuronal subtype-specific loci, suggesting that such identity can be imparted by additional lineage-specific transcription factors. Consistently, we show that ISL1 and LHX3 selectively drive conversion to a highly homogeneous population of human spinal cord motor neurons. This study shows that modular synergism between miRNAs and neuronal subtype-specific transcription factors can drive lineage-specific neuronal reprogramming, providing a general platform for high-efficiency generation of distinct subtypes of human neurons. [Display omitted] •miR-9/9∗ and miR-124 reprogram adult human fibroblasts to a default neuronal state•miR-9/9∗ and miR-124 orchestrate dramatic chromatin reconfigurations•miRNA reprogramming opens neuronal subtype-specific loci•Terminal selector genes program default neuronal state to a motor neuron identity Abernathy et al. show that widespread epigenetic changes underlie miRNA-mediated direct reprogramming of primary adult human fibroblasts into neurons, revealing modular synergism between miRNAs and transcription factors to allow lineage-specific neuronal reprogramming. This work provides a platform for generating distinct subtypes of human neurons from patients.