scholarly journals Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Dorothy P Schafer ◽  
Christopher T Heller ◽  
Georgia Gunner ◽  
Molly Heller ◽  
Christopher Gordon ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rett Syndrome ◽  
Neural Circuits ◽  
Neurodevelopmental Disorder ◽  
Cell Types ◽  
Null Mouse ◽  
Causative Role ◽  
Specific Loss ◽  
Synapse Loss ◽  
Circuit Defects

Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder<xref ref-type="bibr" rid="bib19"/><xref ref-type="bibr" rid="bib15"/><xref ref-type="bibr" rid="bib37"/><xref ref-type="bibr" rid="bib47"/>. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role<xref ref-type="bibr" rid="bib67"/>. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2tm1.1Bird/y). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1CreER;Mecp2fl/yor Cx3cr1CreER; Mecp2LSL/y) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types.

scholarly journals Pharmacological read-through of R294X Mecp2 in a novel mouse model of Rett syndrome

2020 ◽  
Vol 29 (15) ◽  
pp. 2461-2470
Author(s):  
Jonathan K Merritt ◽  
Bridget E Collins ◽  
Kirsty R Erickson ◽  
Hongwei Dong ◽  
Jeffrey L Neul
Keyword(s):  
Mouse Model ◽  
Rett Syndrome ◽  
Therapeutic Approach ◽  
Neurodevelopmental Disorder ◽  
Intraperitoneal Administration ◽  
Full Length ◽  
Nonsense Suppression ◽  
Null Mouse ◽  
Peripheral Tissues ◽  
Mecp2 Protein

Abstract Rett syndrome (RTT) is a neurodevelopmental disorder primarily caused by mutations in Methyl-CpG-binding Protein 2 (MECP2). More than 35% of affected individuals have nonsense mutations in MECP2. For these individuals, nonsense suppression has been suggested as a possible therapeutic approach. To assess the viability of this strategy, we created and characterized a mouse model with the common p.R294X mutation introduced into the endogenous Mecp2 locus (Mecp2R294X). Mecp2R294X mice exhibit phenotypic abnormalities similar to those seen in complete null mouse models; however, these occur at a later time point consistent with the reduced phenotypic severity seen in affected individuals containing this specific mutation. The delayed onset of severe phenotypes is likely due to the presence of truncated MeCP2 in Mecp2R294X mice. Supplying the MECP2 transgene in Mecp2R294X mice rescued phenotypic abnormalities including early death and demonstrated that the presence of truncated MeCP2 in these mice does not interfere with wild-type MeCP2. In vitro treatment of a cell line derived from Mecp2R294X mice with the nonsense suppression agent G418 resulted in full-length MeCP2 protein production, demonstrating feasibility of this therapeutic approach. Intraperitoneal administration of G418 in Mecp2R294X mice was sufficient to elicit full-length MeCP2 protein expression in peripheral tissues. Finally, intracranial ventricular injection of G418 in Mecp2R294X mice induced expression of full-length MeCP2 protein in the mouse brain. These experiments demonstrate that translational read-through drugs are able to suppress the Mecp2 p.R294X mutation in vivo and provide a proof of concept for future preclinical studies of nonsense suppression agents in RTT.

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 Inflammatory Lung Disease in Rett Syndrome

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Claudio De Felice ◽  
Marcello Rossi ◽  
Silvia Leoncini ◽  
Glauco Chisci ◽  
Cinzia Signorini ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Neurodevelopmental Disorder ◽  
Upper Airway ◽  
Redox Status ◽  
Null Mouse ◽  
Gene Encoding ◽  
Respiratory Dysfunction ◽  
Lung Histology ◽  
Reduced And Oxidized Glutathione ◽  
Major Target

Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly linked to mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Respiratory dysfunction, historically credited to brainstem immaturity, represents a major challenge in RTT. Our aim was to characterize the relationships between pulmonary gas exchange abnormality (GEA), upper airway obstruction, and redox status in patients with typical RTT (n= 228) and to examine lung histology in aMecp2-null mouse model of the disease. GEA was detectable in ~80% (184/228) of patients versus ~18% of healthy controls, with “high” (39.8%) and “low” (34.8%) patterns dominating over “mixed” (19.6%) and “simple mismatch” (5.9%) types. Increased plasma levels of non-protein-bound iron (NPBI), F2-isoprostanes (F2-IsoPs), intraerythrocyte NPBI (IE-NPBI), and reduced and oxidized glutathione (i.e., GSH and GSSG) were evidenced in RTT with consequently decreased GSH/GSSG ratios. Apnea frequency/severity was positively correlated with IE-NPBI, F2-IsoPs, and GSSG and negatively with GSH/GSSG ratio. A diffuse inflammatory infiltrate of the terminal bronchioles and alveoli was evidenced in half of the examinedMecp2-mutant mice, well fitting with the radiological findings previously observed in RTT patients. Our findings indicate that GEA is a key feature of RTT and that terminal bronchioles are a likely major target of the disease.

scholarly journals Severe changes in colon epithelium in the Mecp2-null mouse model of Rett syndrome

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Pamela Millar-Büchner ◽  
Amber R. Philp ◽  
Noemí Gutierrez ◽  
Sandra Villanueva ◽  
Bredford Kerr ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rett Syndrome ◽  
Null Mouse

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 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 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 Effects of early-life exposure to THIP on brainstem neuronal excitability in the Mecp2 -null mouse model of Rett syndrome before and after drug withdrawal

2017 ◽  
Vol 5 (2) ◽  
pp. e13110 ◽  
Author(s):  
Weiwei Zhong ◽  
Christopher M. Johnson ◽  
Ningren Cui ◽  
Max F. Oginsky ◽  
Yang Wu ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rett Syndrome ◽  
Early Life ◽  
Neuronal Excitability ◽  
Drug Withdrawal ◽  
Null Mouse ◽  
Early Life Exposure ◽  
Before And After
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