A small-molecule screen reveals novel modulators of MeCP2 and X-chromosome inactivation maintenance

Hyeong-Min Lee,Ellen P Clark,Agnieszka Kokot,Benjamin D Philpot,Noah Sciaky,M Bram Kuijer,Nerea Ruiz Blanes,Sanchita Bhatnagar,Jeremy M Simon,Lorena Galiano Arjona,Megumi Aita,Andrea Cerase

doi:10.1186/s11689-020-09332-3

Abstract

BackgroundRett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 (MeCP2) gene. While MeCP2 mutations are lethal in most males, females survive birth but show severe neurological defects. Because X-chromosome inactivation (XCI) is a random process, approximately 50% of the cells silence the wild-type (WT) copy of the MeCP2 gene. Thus, reactivating the silent WT copy of MeCP2 could provide therapeutic intervention for RTT.MethodsToward this goal, we screened ~ 28,000 small-molecule compounds from several libraries using a MeCP2-luciferase reporter cell line and cortical neurons from a MeCP2-EGFP mouse model. We used gain/increase of luminescence or fluorescence as a readout of MeCP2 reactivation and tested the efficacy of these drugs under different drug regimens, conditions, and cellular contexts.ResultsWe identified inhibitors of the JAK/STAT pathway as XCI-reactivating agents, both by in vitro and ex vivo assays. In particular, we show that AG-490, a Janus Kinase 2 (JAK2) kinase inhibitor, and Jaki, a pan JAK/STAT inhibitor, are capable of reactivating MeCP2 from the inactive X chromosome, in different cellular contexts.ConclusionsOur results suggest that inhibition of the JAK/STAT pathway is a new potential pathway to reinstate MeCP2 gene expression as an efficient RTT treatment.

Highlights

Rett syndrome (RTT) is a severe neurodevelopmental disorder often classified as an autism spectrum disorder (ASD)
We found that two JAK/STAT pathway inhibitors, AG490 and Jaki, could reproducibly reactivate methylCpG binding protein 2 (MeCP2)
AG490 is a potential reactivator of X-linked genes To identify compounds that are capable of reactivating the inactive copy of MeCP2, we employed highthroughput, high-content screens using multiple chemical libraries

Summary

Introduction

Rett syndrome (RTT) is a severe neurodevelopmental disorder often classified as an autism spectrum disorder (ASD). About 90% of reported cases of individuals with RTT inherit de novo mutations of the methyl-CpGbinding protein 2 (MeCP2) gene [1]. Antiepileptic drugs provide symptomatic relief for many of the ~ 60% of RTT individuals affected by seizures [14, 15]. Other treatment options include physical therapy, speech therapy, occupational therapy, and psychosocial support for families. Management of these conditions can substantially improve the quality of life in individuals with RTT [20]. Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked methylCpG binding protein 2 (MeCP2) gene. Reactivating the silent WT copy of MeCP2 could provide therapeutic intervention for RTT

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