MicroRNAs Overcome Cell Fate Barrier by Reducing EZH2-Controlled REST Stability during Neuronal Conversion of Human Adult Fibroblasts

Publication date: 2 July 2018
Source:Developmental Cell, Volume 46, Issue 1
Author(s): Seong Won Lee, Young Mi Oh, Ya-Lin Lu, Woo Kyung Kim, Andrew S. Yoo
The ability to convert human somatic cells efficiently to neurons facilitates the utility of patient-derived neurons for studying neurological disorders. As such, ectopic expression of neuronal microRNAs (miRNAs), miR-9/9^∗ and miR-124 (miR-9/9^∗-124) in adult human fibroblasts has been found to evoke extensive reconfigurations of the chromatin and direct the fate conversion to neurons. However, how miR-9/9^∗-124 break the cell fate barrier to activate the neuronal program remains to be defined. Here, we identified an anti-neurogenic function of EZH2 in fibroblasts that acts outside its role as a subunit of Polycomb Repressive Complex 2 to directly methylate and stabilize REST, a transcriptional repressor of neuronal genes. During neuronal conversion, miR-9/9^∗-124 induced the repression of the EZH2-REST axis by downregulating USP14, accounting for the opening of chromatin regions harboring REST binding sites. Our findings underscore the interplay between miRNAs and protein stability cascade underlying the activation of neuronal program.

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Teaser

Ectopic expression of neuronal microRNAs miR-9/9^∗ and miR-124 in adult human fibroblasts induces chromatin changes and fate conversion to neurons. Lee et al. uncover the regulatory basis, showing that the miRNAs trigger repression of EZH2 and disrupt its PRC2-independent role in methylating and stabilizing REST to form an anti-neurogenic barrier.


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