# Molecular Pathogenesis Studies of Rett Syndrome

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2020 · $346,719

## Abstract

ABSTRACT
The long-term goal of this proposal is to understand the molecular activities of methyl CpG-binding protein 2
(MeCP2) in order to develop viable treatment options for Rett syndrome (RTT) and other MeCP2-related
disorders, which range from severe neonatal encephalopathy to autism, juvenile onset schizophrenia and other
neuropsychiatric conditions. Three key discoveries in the past four years have changed the way we think about
MeCP2. First, we and others have shown that MeCP2 binds to non-CpG methylated dinucleotides (“mCH”) as
well as methylated CpG dinucleotides (“mCG”), and that this binding correlates with transcriptional changes in
mouse models of RTT and MECP2 duplication syndrome. Second, we discovered a functional AT-hook domain
in MeCP2 and evidence that suggests it remodels chromatin. Third, we have shown that the brain is sensitive to
levels of MeCP2 expression and that antisense oligonucleotides (ASOs) can reduce MeCP2 levels in a mouse
model of the MeCP2 duplication syndrome and reverse the disease. In this proposal we capitalize on these and
other recent discoveries to gain deeper insight into RTT pathophysiology and the role of MeCP2 in maintaining
healthy neuronal responsiveness. In Aim 1, we will delineate the contributions of non-CpG methylation to RTT
pathogenesis by deleting the mCH “writer”, Dnmt3a, from GABA-expressing neurons (to ablate mCH) and
comparing the resulting phenotype and gene expression changes to those of mice lacking Mecp2 (our
hypothesized mCH “reader”) in precisely the same neurons. In Aim 2, we will find what happens once MeCP2
binds its genomic targets, whether mCG or mCH, by using the newly developed in situ Hi-C approach to
ascertain the 3D chromatin structure in the cerebellum and dentate gyrus in tissue from wild-type, MeCP2 null,
and MeCP2 overexpressing mice. Because neuronal activity leads to a multitude of epigenetic changes, as well
as altering the interactions of MeCP2, we will also perform in situ Hi-C in the dentate gyrus both before and
after neuronal stimulation. In Aim 3a, we will expand on our successful ASO studies to prepare for translation
by testing them in a MeCP2 duplication syndrome mouse that expresses two human MECP2 alleles (just like
the patients) to titrate the ASO dose that will restore the protein levels from 2X to 1X, and identify the
boundaries of safe MeCP2 levels. In Aim 3b, we will apply a novel forward genetic screening strategy that we
developed for finding molecules that alter levels of other disease-related proteins to identify druggable targets
that either decrease or increase MeCP2 levels. (Some Rett-causing MeCP2 mutations reduce the protein's
level.) Our shRNA screen targets a 7,787 druggable gene collection using a DsRed- IRES-MeCP2-EGFP
reporter cell line that allows high-throughput monitoring of MeCP2 levels. Targets will be validated and those
with most promising safety profiles will be advanced for in vivo studies. In sum, the proposed studies will
gr...

## Key facts

- **NIH application ID:** 9905561
- **Project number:** 5R01NS057819-15
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** HUDA Y ZOGHBI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $346,719
- **Award type:** 5
- **Project period:** 2006-09-04 → 2021-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9905561

## Citation

> US National Institutes of Health, RePORTER application 9905561, Molecular Pathogenesis Studies of Rett Syndrome (5R01NS057819-15). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9905561. Licensed CC0.

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