Project description:MECP2 duplication syndrome, a childhood neurological disorder characterized by autism, intellectual disability, motor dysfunction, anxiety and epilepsy, is caused by a duplication on chromosome Xq28 spanning the MECP2 gene that results in doubling of MeCP2 levels. MECP2 overexpression in mice causes neurobehavioral and electroencephalographic defects similar to those of human patients, but the gross anatomy of the brain remains unaffected. We hypothesized that MECP2 duplication syndrome would be reversible and tested two methods to restore MeCP2 levels to normal: conditional genetic recombination and antisense oligonucleotide therapy. Both approaches rescued molecular, physiological and behavioral features of adult symptomatic mice. Antisense therapy also restored normal MeCP2 levels in lymphoblastoid cells from MECP2 duplication patients, in a dose-dependent manner. Our data indicate that antisense oligonucleotides could provide a viable therapeutic approach for human MECP2 duplication syndrome as well as other disorders involving copy number gains.
Project description:MECP2 duplication syndrome, a childhood neurological disorder characterized by autism, intellectual disability, motor dysfunction, anxiety and epilepsy, is caused by a duplication on chromosome Xq28 spanning the MECP2 gene that results in doubling of MeCP2 levels. MECP2 overexpression in mice causes neurobehavioral and electroencephalographic defects similar to those of human patients, but the gross anatomy of the brain remains unaffected. We hypothesized that MECP2 duplication syndrome would be reversible and tested two methods to restore MeCP2 levels to normal: conditional genetic recombination and antisense oligonucleotide therapy. Both approaches rescued molecular, physiological and behavioral features of adult symptomatic mice. Antisense therapy also restored normal MeCP2 levels in lymphoblastoid cells from MECP2 duplication patients, in a dose-dependent manner. Our data indicate that antisense oligonucleotides could provide a viable therapeutic approach for human MECP2 duplication syndrome as well as other disorders involving copy number gains.
Project description:MECP2 duplication syndrome, a childhood neurological disorder characterized by autism, intellectual disability, motor dysfunction, anxiety and epilepsy, is caused by a duplication on chromosome Xq28 spanning the MECP2 gene that results in doubling of MeCP2 levels. MECP2 overexpression in mice causes neurobehavioral and electroencephalographic defects similar to those of human patients, but the gross anatomy of the brain remains unaffected. We hypothesized that MECP2 duplication syndrome would be reversible and tested two methods to restore MeCP2 levels to normal: conditional genetic recombination and antisense oligonucleotide therapy. Both approaches rescued molecular, physiological and behavioral features of adult symptomatic mice. Antisense therapy also restored normal MeCP2 levels in lymphoblastoid cells from MECP2 duplication patients, in a dose-dependent manner. Our data indicate that antisense oligonucleotides could provide a viable therapeutic approach for human MECP2 duplication syndrome as well as other disorders involving copy number gains.
Project description:Neurodevelopmental disorders (NDDs) are genetically heterogeneous, yet often share certain features such as intellectual disability or motor incoordination. MeCP2 dysfunction is associated with MECP2 duplication syndrome and Rett syndrome (RTT), the phenotypes of which overlap with other NDDs, yet the precise molecular pathogenesis remains unclear. Using proximity-dependent biotinylation (BioID), we identified a novel TCF20 complex that interacts with MeCP2 through its subunit PHF14. TCF20 regulates the expression of key neuronal genes, many of which are co-regulated by MeCP2. Reducing Tcf20 partially rescued the behavioral deficits caused by MECP2 overexpression, underscoring a functional relationship between MeCP2 and TCF20 in NDD pathogenesis. We identified a patient with a missense mutation in PHF14 that abolishes the MeCP2-PHF14-TCF20 interaction who exhibits neurological features seen in RTT. These data demonstrate the critical role of MeCP2-TCF20 complex interaction for brain function.
Project description:We compared gene expression changes in the cerebellum of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased copy number of the gene causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however the gene expression changes observed in the hypothalamus of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. To determine if this dual role of MeCP2 extends beyond the hypothalamus, we studied gene expression patterns in the cerebellum of Mecp2-null and MECP2-Tg mice, modeling RTT and MECP2 duplication syndrome, respectively. We found that abnormal MeCP2 dosage causes alterations in the expression of hundreds of genes in the cerebellum. The majority of genes were upregulated in MECP2-Tg mice and downregulated in Mecp2-null mice, consistent with a role for MeCP2 as a modulator that can both increase and decrease gene expression. Interestingly, many of the genes altered in the cerebellum, particularly those increased by the presence of MeCP2 and decreased in its absence, were similarly altered in the hypothalamus. Keywords: Comparison of cerebellar gene expression data between Mecp2-null mice and Mecp2-transgenic mice Total cerebellar RNA samples were collected from Mecp2-null male mice (n=5), MECP2-transgenic male mice (n=5), and their wild type male littermates at 6 weeks of age (n=5 for each group).
Project description:We compared gene expression changes in the cerebellum of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased copy number of the gene causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however the gene expression changes observed in the hypothalamus of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. To determine if this dual role of MeCP2 extends beyond the hypothalamus, we studied gene expression patterns in the cerebellum of Mecp2-null and MECP2-Tg mice, modeling RTT and MECP2 duplication syndrome, respectively. We found that abnormal MeCP2 dosage causes alterations in the expression of hundreds of genes in the cerebellum. The majority of genes were upregulated in MECP2-Tg mice and downregulated in Mecp2-null mice, consistent with a role for MeCP2 as a modulator that can both increase and decrease gene expression. Interestingly, many of the genes altered in the cerebellum, particularly those increased by the presence of MeCP2 and decreased in its absence, were similarly altered in the hypothalamus. Keywords: Comparison of cerebellar gene expression data between Mecp2-null mice and Mecp2-transgenic mice
Project description:Methyl-CpG binding protein 2 (MeCP2) is a nuclear protein that binds to methylated cytosines and regulates gene expression. Normal brain function requires precise control of MeCP2 level. Loss of function mutations in the X-linked gene, MECP2 cause Rett Syndrome (RTT), a progressive neurological disorder. Increase in MeCP2 level leads to the neurological disorder MECP2 duplication syndrome (MDS). Despite the functional importance of MeCP2 in the brain, its transcriptional regulation remains poorly understood. Here, we utilized ATAC-seq in the mouse brain across development to identify five putative adult brain cis-regulatory elements (CREs) of Mecp2. We found that knocking out these CREs using CRISPR-Cas9 altered Mecp2 levels. Furthermore, two of the CREs were conserved in human, and when we delete either of these in mice, the animals show progressive neurological dysfunction. Deletion of one of the conserved CREs led to a decreased MeCP2 level and caused phenotypes similar, albeit milder, to those seen in Mecp2-null mice whereas the deletion of the second CRE led to an increased MeCP2 level and phenotypically resembled, but also milder than, MECP2 duplication mice. Deleting these two conserved CREs levels in human iPSC-derived neurons also similarly altered MECP2 levels. Taken together, our discovery of CREs that modulate Mecp2/MECP2 expression provides insight into regulation of Mecp2/MECP2 in the mouse brain and human neurons, respectively. These CREs could be candidate sites for non-coding mutations that lead to neurodevelopmental disorders characterized by partial features of RTT or MDS.