scholarly journals Restoration of Mecp2 expression in GABAergic neurons is sufficient to rescue multiple disease features in a mouse model of Rett syndrome

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Kerstin Ure ◽  
Hui Lu ◽  
Wei Wang ◽  
Aya Ito-Ishida ◽  
Zhenyu Wu ◽  
...  
Keyword(s):  
Social Skills ◽  
Mouse Model ◽  
Rett Syndrome ◽  
Therapeutic Option ◽  
Neurodevelopmental Disorder ◽  
Gabaergic Neurons ◽  
Inhibitory Neurons ◽  
Extended Lifespan ◽  
Inhibitory Signaling

The postnatal neurodevelopmental disorder Rett syndrome, caused by mutations in MECP2, produces a diverse array of symptoms, including loss of language, motor, and social skills and the development of hand stereotypies, anxiety, tremor, ataxia, respiratory dysrhythmias, and seizures. Surprisingly, despite the diversity of these features, we have found that deleting Mecp2 only from GABAergic inhibitory neurons in mice replicates most of this phenotype. Here we show that genetically restoring Mecp2 expression only in GABAergic neurons of male Mecp2 null mice enhanced inhibitory signaling, extended lifespan, and rescued ataxia, apraxia, and social abnormalities but did not rescue tremor or anxiety. Female Mecp2+/- mice showed a less dramatic but still substantial rescue. These findings highlight the critical regulatory role of GABAergic neurons in certain behaviors and suggest that modulating the excitatory/inhibitory balance through GABAergic neurons could prove a viable therapeutic option in Rett syndrome.

scholarly journals Rett Syndrome in Males: The Different Clinical Course in Two Brothers with the Same Microduplication MECP2 Xq28

2019 ◽  
Vol 16 (17) ◽  
pp. 3075
Author(s):  
Maria Bernarda Pitzianti ◽  
Angelo Santamaria Palombo ◽  
Susanna Esposito ◽  
Augusto Pasini
Keyword(s):  
Rett Syndrome ◽  
Genetic Basis ◽  
Normal Development ◽  
Clinical Course ◽  
Neurodevelopmental Disorder ◽  
Dominant Inheritance ◽  
Clinical Form ◽  
Inactivation Pattern ◽  
History Of

Rett syndrome (RTT) is a neurodevelopmental disorder with a genetic basis that is associated with the mutation of the X-linked methyl-CpG binding protein 2 (MECP2) gene in approximately 90% of patients. RTT is characterized by a brief period of normal development followed by loss of acquired skills and evolution towards impairment of brain and motor functions and multi-organ dysfunction. Originally, RTT was considered lethal in males as it has an X-linked dominant inheritance. However, although this syndrome has a higher incidence in females, rare cases are also documented in males. Here, we describe the case of an 11-year-old male patient with a microduplication MECP2 Xq28. Our patient is currently living, while his older brother with the same mutation died at the age of 9 years. We showed that the role of MECP2 as an epigenetic modulator and the X-chromosome inactivation pattern can explain the lethal clinical form of the older brother with the same microduplication MECP2 Xq28 presented by our patient who is still alive. Given the limited case history of RTT in males, further studies are needed to better characterize this syndrome in males and consequently improve the currently available therapeutic strategies.

scholarly journals Biallelic truncation variants in ATP9A are associated with a novel autosomal recessive neurodevelopmental disorder

2021 ◽  
Author(s):  
Francesca Mattioli ◽  
Hossein Darvish ◽  
Sohail Aziz Paracha ◽  
Abbas Tafakhori ◽  
Saghar Ghasemi Firouzabadi ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Mouse Model ◽  
Autosomal Recessive ◽  
High Throughput Sequencing ◽  
Neurodevelopmental Disorder ◽  
Behavioral Changes ◽  
Causative Role ◽  
Speech Impairment ◽  
Lipid Flippase

Intellectual disability (ID) is a highly heterogeneous disorder with hundreds of associated genes. Despite progress in the identification of the genetic causes of ID following the introduction of high-throughput sequencing, about half of affected individuals still remain without a molecular diagnosis. Consanguineous families with affected individuals provide a unique opportunity to identify novel recessive causative genes. In this report we describe a novel autosomal recessive neurodevelopmental disorder. We identified two consanguineous families with homozygous variants predicted to alter the splicing of ATP9A which encodes a transmembrane lipid flippase of the class II P4-ATPases. The three individuals homozygous for these putatively truncating variants presented with severe ID, motor and speech impairment, and behavioral anomalies. Consistent with a causative role of ATP9A in these patients, a previously described Atp9a-/- mouse model showed behavioral changes.

scholarly journals MeCP2: The Genetic Driver of Rett Syndrome Epigenetics

2021 ◽  
Vol 12 ◽  
Author(s):  
Katrina V. Good ◽  
John B. Vincent ◽  
Juan Ausió
Keyword(s):  
Rett Syndrome ◽  
Neuronal Development ◽  
Neurodevelopmental Disorder ◽  
Epigenetic Mark ◽  
Initial Development ◽  
Genetic Ablation ◽  
Developmental Regression ◽  
The Stability ◽  
The Brain

Mutations in methyl CpG binding protein 2 (MeCP2) are the major cause of Rett syndrome (RTT), a rare neurodevelopmental disorder with a notable period of developmental regression following apparently normal initial development. Such MeCP2 alterations often result in changes to DNA binding and chromatin clustering ability, and in the stability of this protein. Among other functions, MeCP2 binds to methylated genomic DNA, which represents an important epigenetic mark with broad physiological implications, including neuronal development. In this review, we will summarize the genetic foundations behind RTT, and the variable degrees of protein stability exhibited by MeCP2 and its mutated versions. Also, past and emerging relationships that MeCP2 has with mRNA splicing, miRNA processing, and other non-coding RNAs (ncRNA) will be explored, and we suggest that these molecules could be missing links in understanding the epigenetic consequences incurred from genetic ablation of this important chromatin modifier. Importantly, although MeCP2 is highly expressed in the brain, where it has been most extensively studied, the role of this protein and its alterations in other tissues cannot be ignored and will also be discussed. Finally, the additional complexity to RTT pathology introduced by structural and functional implications of the two MeCP2 isoforms (MeCP2-E1 and MeCP2-E2) will be described. Epigenetic therapeutics are gaining clinical popularity, yet treatment for Rett syndrome is more complicated than would be anticipated for a purely epigenetic disorder, which should be taken into account in future clinical contexts.

scholarly journals Persistent Unresolved Inflammation in the Mecp2-308 Female Mutated Mouse Model of Rett Syndrome

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Alessio Cortelazzo ◽  
Claudio De Felice ◽  
Bianca De Filippis ◽  
Laura Ricceri ◽  
Giovanni Laviola ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rett Syndrome ◽  
Binding Protein ◽  
Neurodevelopmental Disorder ◽  
Unknown Origin ◽  
Apolipoprotein A1 ◽  
Inflammatory Status ◽  
Truncating Mutation ◽  
Alpha 1 Antitrypsin ◽  
First Time

Rett syndrome (RTT) is a rare neurodevelopmental disorder usually caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). Several Mecp2 mutant mouse lines have been developed recapitulating part of the clinical features. In particular, Mecp2-308 female heterozygous mice, bearing a truncating mutation, are a validated model of the disease. While recent data suggest a role for inflammation in RTT, little information on the inflammatory status in murine models of the disease is available. Here, we investigated the inflammatory status by proteomic 2-DE/MALDI-ToF/ToF analyses in symptomatic Mecp2-308 female mice. Ten differentially expressed proteins were evidenced in the Mecp2-308 mutated plasma proteome. In particular, 5 positive acute-phase response (APR) proteins increased (i.e., kininogen-1, alpha-fetoprotein, mannose-binding protein C, alpha-1-antitrypsin, and alpha-2-macroglobulin), and 3 negative APR reactants were decreased (i.e., serotransferrin, albumin, and apolipoprotein A1). CD5 antigen-like and vitamin D-binding protein, two proteins strictly related to inflammation, were also changed. These results indicate for the first time a persistent unresolved inflammation of unknown origin in the Mecp2-308 mouse model.

scholarly journals Activity-dependent aberrations in gene expression and alternative splicing in a mouse model of Rett syndrome

2018 ◽  
Vol 115 (23) ◽  
pp. E5363-E5372 ◽  
Author(s):  
Sivan Osenberg ◽  
Ariel Karten ◽  
Jialin Sun ◽  
Jin Li ◽  
Shaun Charkowick ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Mouse Model ◽  
Rett Syndrome ◽  
Neuronal Activity ◽  
Intron Retention ◽  
Neurodevelopmental Disorder ◽  
Fine Tuning ◽  
Global Pattern ◽  
Activity Dependent

Rett syndrome (RTT) is a severe neurodevelopmental disorder that affects about 1 in 10,000 female live births. The underlying cause of RTT is mutations in the X-linked gene, methyl-CpG-binding protein 2 (MECP2); however, the molecular mechanism by which these mutations mediate the RTT neuropathology remains enigmatic. Specifically, although MeCP2 is known to act as a transcriptional repressor, analyses of the RTT brain at steady-state conditions detected numerous differentially expressed genes, while the changes in transcript levels were mostly subtle. Here we reveal an aberrant global pattern of gene expression, characterized predominantly by higher levels of expression of activity-dependent genes, and anomalous alternative splicing events, specifically in response to neuronal activity in a mouse model for RTT. Notably, the specific splicing modalities of intron retention and exon skipping displayed a significant bias toward increased retained introns and skipped exons, respectively, in the RTT brain compared with the WT brain. Furthermore, these aberrations occur in conjunction with higher seizure susceptibility in response to neuronal activity in RTT mice. Our findings advance the concept that normal MeCP2 functioning is required for fine-tuning the robust and immediate changes in gene transcription and for proper regulation of alternative splicing induced in response to neuronal stimulation.

scholarly journals MeCP2 Is Required for Normal Development of GABAergic Circuits in the Thalamus

2010 ◽  
Vol 103 (5) ◽  
pp. 2470-2481 ◽  
Author(s):  
Zhong-Wei Zhang ◽  
Joseph D. Zak ◽  
Hong Liu
Keyword(s):  
Neurodevelopmental Disorder ◽  
Brain Slices ◽  
Inhibitory Neurons ◽  
Gene Encoding ◽  
Vertebrate Brain ◽  
Gabaergic Synapses ◽  
And Function ◽  
Kinetics Of ◽  
Whole Cell Recordings

Methyl-CpG binding protein 2 (MeCP2) is highly expressed in neurons in the vertebrate brain, and mutations of the gene encoding MeCP2 cause the neurodevelopmental disorder Rett syndrome. This study examines the role of MeCP2 in the development and function of thalamic GABAergic circuits. Whole cell recordings were carried out in excitatory neurons of the ventrobasal complex (VB) of the thalamus and in inhibitory neurons of the reticular thalamic nucleus (RTN) in acute brain slices from mice aged P6 through P23. At P14–P16, the number of quantal GABAergic events was decreased in VB neurons but increased in RTN neurons of Mecp2-null mice, without any change in the amplitude or kinetics of quantal events. There was no difference between mutant and wild-type mice in paired-pulse ratios of evoked GABAergic responses in the VB or the RTN. On the other hand, unitary responses evoked by minimal stimulation were decreased in the VB but increased in the RTN of mutants. Similar changes in the frequency of quantal events were observed at P21–P23 in both the VB and RTN. At P6, however, quantal GABAergic transmission was altered only in the VB not the RTN. Immunostaining of vesicular GABA transporter showed opposite changes in the number of GABAergic synaptic terminals in the VB and RTN of Mecp2-null mice at P18–P20. The loss of MeCP2 had no significant effect on intrinsic properties of RTN neurons recorded at P15–P17. Our findings suggest that MeCP2 differentially regulates the development of GABAergic synapses in excitatory and inhibitory neurons in the thalamus.

scholarly journals Sex disparate gut microbiome and metabolome perturbations precede disease progression in a mouse model of Rett syndrome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kari Neier ◽  
Tianna E. Grant ◽  
Rebecca L. Palmer ◽  
Demario Chappell ◽  
Sophia M. Hakam ◽  
...  
Keyword(s):  
Mouse Model ◽  
Disease Progression ◽  
Rett Syndrome ◽  
Gut Microbiome ◽  
Neurodevelopmental Disorder ◽  
Molecular Pathways ◽  
Linked Gene ◽  
Disease Phenotypes ◽  
Altered Metabolism ◽  
Inflammatory Profile

AbstractRett syndrome (RTT) is a regressive neurodevelopmental disorder in girls, characterized by multisystem complications including gut dysbiosis and altered metabolism. While RTT is known to be caused by mutations in the X-linked gene MECP2, the intermediate molecular pathways of progressive disease phenotypes are unknown. Mecp2 deficient rodents used to model RTT pathophysiology in most prior studies have been male. Thus, we utilized a patient-relevant mouse model of RTT to longitudinally profile the gut microbiome and metabolome across disease progression in both sexes. Fecal metabolites were altered in Mecp2e1 mutant females before onset of neuromotor phenotypes and correlated with lipid deficiencies in brain, results not observed in males. Females also displayed altered gut microbial communities and an inflammatory profile that were more consistent with RTT patients than males. These findings identify new molecular pathways of RTT disease progression and demonstrate the relevance of further study in female Mecp2 animal models.

scholarly journals JNK signaling provides a novel therapeutic target for Rett syndrome

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Clara Alice Musi ◽  
Anna Maria Castaldo ◽  
Anna Elisa Valsecchi ◽  
Sara Cimini ◽  
Noemi Morello ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Clinical Symptoms ◽  
Neurodevelopmental Disorder ◽  
Loss Of Function ◽  
Jnk Signaling ◽  
Functional Changes ◽  
Jnk Activation ◽  
Stress Pathway

Abstract Background Rett syndrome (RTT) is a monogenic X-linked neurodevelopmental disorder characterized by loss-of-function mutations in the MECP2 gene, which lead to structural and functional changes in synapse communication, and impairments of neural activity at the basis of cognitive deficits that progress from an early age. While the restoration of MECP2 in animal models has been shown to rescue some RTT symptoms, gene therapy intervention presents potential side effects, and with gene- and RNA-editing approaches still far from clinical application, strategies focusing on signaling pathways downstream of MeCP2 may provide alternatives for the development of more effective therapies in vivo. Here, we investigate the role of the c-Jun N-terminal kinase (JNK) stress pathway in the pathogenesis of RTT using different animal and cell models and evaluate JNK inhibition as a potential therapeutic approach. Results We discovered that the c-Jun N-terminal kinase (JNK) stress pathway is activated in Mecp2-knockout, Mecp2-heterozygous mice, and in human MECP2-mutated iPSC neurons. The specific JNK inhibitor, D-JNKI1, promotes recovery of body weight and locomotor impairments in two mouse models of RTT and rescues their dendritic spine alterations. Mecp2-knockout presents intermittent crises of apnea/hypopnea, one of the most invalidating RTT pathological symptoms, and D-JNKI1 powerfully reduces this breathing dysfunction. Importantly, we discovered that also neurons derived from hiPSC-MECP2 mut show JNK activation, high-phosphorylated c-Jun levels, and cell death, which is not observed in the isogenic control wt allele hiPSCs. Treatment with D-JNKI1 inhibits neuronal death induced by MECP2 mutation in hiPSCs mut neurons. Conclusions As a summary, we found altered JNK signaling in models of RTT and suggest that D-JNKI1 treatment prevents clinical symptoms, with coherent results at the cellular, molecular, and functional levels. This is the first proof of concept that JNK plays a key role in RTT and its specific inhibition offers a new and potential therapeutic tool to tackle RTT.

Sign in / Sign up

Export Citation Format

Share Document