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Updated: Dec 1, 2025
Pooled shRNA Screen for Reactivation of MeCP2 on the Inactive X Chromosome
Published on: March 2, 2018
A small-molecule screen reveals novel modulators of MeCP2 and X-chromosome inactivation maintenance
Hyeong-Min Lee1,2,3, M Bram Kuijer1, Nerea Ruiz Blanes4
1Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
Background:
Rett 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.
Methods:
Toward 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.
Results:
We 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.
Conclusions:
Our results suggest that inhibition of the JAK/STAT pathway is a new potential pathway to reinstate MeCP2 gene expression as an efficient RTT treatment.
Insights
Inhibiting the JAK/STAT pathway can reactivate the methyl-CpG binding protein 2 (MeCP2) gene, offering a potential treatment for Rett syndrome (RTT). This approach aims to restore MeCP2 expression in affected individuals.
Area of Science:
- Neuroscience
- Genetics
- Pharmacology
Background:
- Rett syndrome (RTT) is a neurodevelopmental disorder stemming from mutations in the methyl-CpG binding protein 2 (MeCP2) gene.
- While typically lethal in males, RTT causes severe neurological deficits in females due to random X-chromosome inactivation (XCI), silencing the functional MeCP2 copy in about half of their cells.
Purpose of the Study:
- To identify therapeutic strategies for RTT by exploring methods to reactivate the silenced wild-type (WT) MeCP2 gene.
- To investigate small-molecule compounds as potential agents for MeCP2 reactivation.
Main Methods:
- Screened approximately 28,000 small-molecule compounds using a MeCP2-luciferase reporter cell line and MeCP2-EGFP mouse cortical neurons.
- Utilized luminescence or fluorescence as indicators of MeCP2 reactivation, testing drug efficacy across various conditions and cellular contexts.
Main Results:
- Identified Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway inhibitors as effective XCI-reactivating agents.
- Demonstrated that AG-490 (a JAK2 inhibitor) and Jaki (a pan JAK/STAT inhibitor) can reactivate MeCP2 from the inactive X chromosome in vitro and ex vivo.
Conclusions:
- Inhibition of the JAK/STAT pathway presents a novel therapeutic avenue for RTT.
- Restoring MeCP2 gene expression through JAK/STAT inhibition offers a promising strategy for RTT treatment.
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