Multiplex epigenome editing of MECP2 to rescue Rett syndrome neurons

Sci Transl Med. 2023 Jan 18;15(679):eadd4666. doi: 10.1126/scitranslmed.add4666. Epub 2023 Jan 18.


Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by loss-of-function heterozygous mutations of methyl CpG-binding protein 2 (MECP2) on the X chromosome in young females. Reactivation of the silent wild-type MECP2 allele from the inactive X chromosome (Xi) represents a promising therapeutic opportunity for female patients with RTT. Here, we applied a multiplex epigenome editing approach to reactivate MECP2 from Xi in RTT human embryonic stem cells (hESCs) and derived neurons. Demethylation of the MECP2 promoter by dCas9-Tet1 with target single-guide RNA reactivated MECP2 from Xi in RTT hESCs without detectable off-target effects at the transcriptional level. Neurons derived from methylation-edited RTT hESCs maintained MECP2 reactivation and reversed the smaller soma size and electrophysiological abnormalities, two hallmarks of RTT. In RTT neurons, insulation of the methylation-edited MECP2 locus by dCpf1-CTCF (a catalytically dead Cpf1 fused with CCCTC-binding factor) with target CRISPR RNA enhanced MECP2 reactivation and rescued RTT-related neuronal defects, providing a proof-of-concept study for epigenome editing to treat RTT and potentially other dominant X-linked diseases.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Epigenome
  • Female
  • Heterozygote
  • Humans
  • Methyl-CpG-Binding Protein 2 / genetics
  • Methyl-CpG-Binding Protein 2 / metabolism
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism
  • Mixed Function Oxygenases / therapeutic use
  • Mutation
  • Neurons / metabolism
  • Proto-Oncogene Proteins / metabolism
  • Rett Syndrome* / genetics
  • Rett Syndrome* / therapy


  • Methyl-CpG-Binding Protein 2
  • TET1 protein, human
  • Mixed Function Oxygenases
  • Proto-Oncogene Proteins