Aspectos neurobiológicos del Síndrome de Rett

El Síndrome de Rett es un trastorno monogénico ligado al cromosoma X, de carácter progresivo que afecta el neurodesarrollo principalmente de niñas durante las primeras etapas del ciclo vital. Su etiología se debe principalmente a las mutaciones de cambio de nucleótido único con pérdida de función del gen MECP2. Este gen codifica para la proteína del mismo nombre cuya principal función es actuar como un represor global de la transcripción mediante el reconocimiento de zonas metiladas de islas CpG y el reclutamiento de factores correpresores que modulan la expresión génica desacetilando histonas. Dentro de las principales alteraciones estructurales asociadas al síndrome se encuentran una morfología neuronal atípica con tamaño del soma neuronal y número de espinas dendríticas reducido, además de alteraciones neuroquímicas sobre todo en la señalización GABAérgica llevando a una desregulación entre señales excitatorias e inhibitorias, causando epilepsia. También se han descrito una serie de alteraciones metabólicas, oxidativas e inflamatorias. El tratamiento hasta ahora se ha enfocado más en buscar un alivio sintomático para las manifestaciones del síndrome pero se ha desarrollado recientemente terapia génica con el objetivo de tratar desde sus bases neurogenéticas la patología y evitar así el desarrollo alterado durante la niñez.

Rett Syndrome is a monogenic disorder linked to the X chromosome, of a progressive nature that affects neurodevelopment mainly in girls during the first stages of the life cycle. Its etiology is mainly due to loss-of-function single nucleotide change mutations of the MECP2 gene. This gene codes for the protein of the same name whose main function is to act as a global repressor of transcription through the recognition of methylated areas of CpG islands and the recruitment of corepressor factors that modulate gene expression by deacetylating histones. Among the main structural alterations associated with the syndrome are an atypical neuronal morphology with a size of the neuronal soma and a reduced number of dendritic spines, in addition to neurochemical alterations, especially in the GABAergic signal, leading to dysregulation between excitatory and inhibitory signals, causing epilepsy. A series of metabolic, oxidative, and inflammatory disorders have also been described. Until now, treatment has focused more on seeking symptomatic relief for the manifestations of the syndrome, but gene therapy has recently been developed with the aim of treating the pathology from its neurogenetic bases and thus avoiding altered development during childhood.

Clinical significance of methyl-CpG binding protein 2 in postherpetic neuralgia: an observational study / Importancia clínica de la proteína 2 de unión a metil-CpG (MECP2) en la neuralgia posherpética: un estudio observacional

Abstract The present study was aimed to investigate the clinical significance of methyl-CpG binding protein 2 (MECP2) in patients with postherpetic neuralgia (PHN). This prospective case control study enrolled 319 cases of PHN patients from April 2017~December 2019. The patients' sleep quality and quality of life were evaluated using the Pittsburgh sleep quality score and the SF- 36 scale, respectively. The serum levels of MECP2, CRP, IL -6 and TNF-α were tested using enzyme linked immunosorbent assay (ELISA). The pain condition of the patients was evaluated using the visual analogue scale (VAS). The levels of MECP2 were significantly increased in PHN patients compared with the patients without PHN. Serum MECP2 levels were the highest in patients with severe pain, and were the lowest in patients with mild pain. Similarly, the frequency of severe pain in patients with low expression of MECP2 was significantly lower than the patients with higher MECP2 expression. Besides, serum levels of inflammatory factors CRP, IL -6 and TNF-α were markedly increased in PHN patients, which were also increased with the increase of the severity of pain. CRP, IL -6 and TNF-α were positively correlated with serum levels of MECP2 in PHN patients. Before the study, patients with lower MECP2 levels showed a significantly higher SF-36 score and lower Pittsburgh and VAS scores than patients with higher levels of MECP2. However, after one month, no significant difference was found between the patients. ROC curve showed MECP2 had the potential as a diagnostic biomarker for PHN. In conclusion, higher serum MECP2 levels are associated with a more severe pain condition and increased release of inflammatory factors.

Resumen El objetivo de este estudio fue investigar la importancia clínica de la MECP2 en pacientes con neuralgia posherpética (NPH). Este estudio observacional prospectivo incluyó 319 pacientes con NPH entre abril de 2017 y diciembre de 2019. La calidad del sueño y la calidad de vida de los pacientes se evaluaron con la escala de calidad del sueño de Pittsburgh y la escala SF - 36, respectivamente. Los niveles séricos de MECP2, PCR, IL -6 y TNF-α fueron determinados por ELISA. Se utilizó la escala visual analógica (EVA) para evaluar la intensidad del dolor. Los niveles de MECP2 en pacientes con NPH aumentaron significativamente en comparación con los pacientes sin NPH. El nivel sérico de MECP2 fue más alto en pacientes con dolor grave y el más bajo en pacientes con dolor leve. Además, la incidencia de dolor grave en pacientes con baja expresión de MECP2 fue significativamente menor que en pacientes con alta expresión de MECP2. Además, los niveles séricos de PCR, IL -6 y TNF-α aumentaron significativamente en pacientes con NPH, y se incrementaron con el aumento del grado de dolor. Los niveles séricos de PCR, IL -6 y TNF-α en pacientes con NPH se correlacionaron positivamente con los niveles séricos de MECP2. Antes del estudio, los pacientes con niveles más bajos de MECP2 tenían puntuaciones significativamente más altas de SF - 36, y puntuaciones más bajas de Pittsburgh y EVA que los pacientes con niveles más altos de MECP2. Sin embargo, no se encontraron diferencias significativas entre los pacientes un mes después. Las curvas ROC mostraron que la MECP2 podría ser un biomarcador de diagnóstico para la NPH. En general, los niveles séricos más altos de la MECP2 se asociaron con condiciones de dolor más graves y un aumento de la liberación de factores inflamatorios.

Astrocytic Gap Junctions Contribute to Aberrant Neuronal Synchronization in a Mouse Model of MeCP2 Duplication Syndrome / 神经科学通报·英文版

Abnormal synchronous neuronal activity has been widely detected by brain imaging of autistic patients, but its underlying neural mechanism remains unclear. Compared with wild-type mice, our in vivo two-photon imaging showed that transgenic (Tg1) mice over-expressing human autism risk gene MeCP2 exhibited higher neuronal synchrony in the young but lower synchrony in the adult stage. Whole-cell recording of neuronal pairs in brain slices revealed that higher neuronal synchrony in young postnatal Tg1 mice was attributed mainly to more prevalent giant slow inward currents (SICs). Both in vivo and slice imaging further demonstrated more dynamic activity and higher synchrony in astrocytes from young Tg1 mice. Blocking astrocytic gap junctions markedly decreased the generation of SICs and overall cell synchrony in the Tg1 brain. Furthermore, the expression level of Cx43 protein and the coupling efficiency of astrocyte gap junctions remained unchanged in Tg1 mice. Thus, astrocytic gap junctions facilitate but do not act as a direct trigger for the abnormal neuronal synchrony in young Tg1 mice, revealing the potential role of the astrocyte network in the pathogenesis of MeCP2 duplication syndrome.

Loss of O-GlcNAcylation on MeCP2 at Threonine 203 Leads to Neurodevelopmental Disorders / 神经科学通报·英文版

Mutations of the X-linked methyl-CpG-binding protein 2 (MECP2) gene in humans are responsible for most cases of Rett syndrome (RTT), an X-linked progressive neurological disorder. While genome-wide screens in clinical trials have revealed several putative RTT-associated mutations in MECP2, their causal relevance regarding the functional regulation of MeCP2 at the etiologic sites at the protein level requires more evidence. In this study, we demonstrated that MeCP2 was dynamically modified by O-linked-β-N-acetylglucosamine (O-GlcNAc) at threonine 203 (T203), an etiologic site in RTT patients. Disruption of the O-GlcNAcylation of MeCP2 specifically at T203 impaired dendrite development and spine maturation in cultured hippocampal neurons, and disrupted neuronal migration, dendritic spine morphogenesis, and caused dysfunction of synaptic transmission in the developing and juvenile mouse cerebral cortex. Mechanistically, genetic disruption of O-GlcNAcylation at T203 on MeCP2 decreased the neuronal activity-induced induction of Bdnf transcription. Our study highlights the critical role of MeCP2 T203 O-GlcNAcylation in neural development and synaptic transmission potentially via brain-derived neurotrophic factor.

Methyl-CpG binding protein 2 is associated with the prognosis and mortality of elderly patients with hip fractures

ABSTRACT Objectives To investigate the expression level and clinical significance of Methyl-CpG binding Protein 2 (MECP2) in elderly patients with hip fractures. Methods This prospective observational study included 367 elderly patients with hip fractures between April 2016 and December 2018. All the patients were treated with internal fixation or joint replacement. In addition, 50 healthy elderly individuals were enrolled as healthy controls. The serum levels of MECP2 and inflammatory factors Interleukin (IL)-1β, IL-6, IL-8, and Tumor Necrosis Factor (TNF)-α was determined by enzyme-linked immunosorbent assay. Data on patients' basic characteristics and postoperative complications were collected. The Harris score was used to assess hip function at 1-month, 3-months, and 6-months after surgery. Patient quality of life was measured using the Barthel Index (BI) score 3-months after surgery. The 1-year mortality was analyzed using the Kaplan-Meier curve, and logical regression was used to analyze the risk factors for mortality. Results No significant differences were observed in the basic clinical characteristics of all patients. The serum MECP2 levels were remarkably high in patients with hip fractures and negatively correlated with serum IL-1β, IL-6, and TNF-α levels. Patients with higher MECP2 predicted higher dynamic Harris scores, lower postoperative complications, lower 1-year mortality, and higher BI scores. Logical regression showed that age was the only independent risk factor for postoperative 1-year mortality in elderly patients with hip fractures. Conclusion Lower MECP2 predicted poor prognosis and higher 1-year mortality in elderly patients with hip fractures.

Síndrome de Rett: reporte de una nueva variante patogénica y revisión de la literatura a propósito de dos casos clínicos / Rett syndrome: report of a new pathogenic variant and review of the literature regarding two clinical cases

Resumen Introducción: El síndrome de Rett es un trastorno del neurodesarrollo con una frecuencia estimada de 1/10,000 recién nacidos vivos, el cual se presenta con un modelo de herencia ligado al cromosoma X. Las variantes patogénicas en el gen MECP2, el cual codifica para una proteína que participa en el desarrollo y la diferenciación del sistema nervioso central, causan este síndrome. El objetivo de este trabajo fue describir dos casos de síndrome de Rett, uno de ellos con una nueva variante del gen MECP2. Casos clínicos: El primer caso se trata de una paciente de 5 años con microcefalia y regresión del neurodesarrollo desde los 3 años. Clínicamente se diagnosticó de síndrome de Rett en estadio III. Se realizó la secuenciación del gen MECP2 y se identificó una variante probablemente patogénica en estado heterocigoto, c.606delC (p.Thr203Argfs*7), que no ha sido reportada previamente. El segundo caso es una paciente de 17 años, referida por discapacidad intelectual grave, que se encontró clínicamente en estadio IV. Se realizó la secuenciación de MECP2 y se identificó una variante patogénica [c.880C>T(p.Arg294*)] ya descrita previamente. Conclusiones: El diagnóstico clínico de síndrome de Rett se llevó a cabo con criterios establecidos. La confirmación diagnóstica fue mediante la secuenciación de MECP2. Para el correcto abordaje de los trastornos del neurodesarrollo es primordial conocer el fenotipo de síndrome de Rett, así como optar por el análisis molecular para la confirmación del diagnóstico. Los pacientes con síndrome de Rett requieren un seguimiento interdisciplinario para disminuir el impacto de las complicaciones.

Abstract Background: Rett syndrome is an X-linked neurodevelopmental disorder with an estimated frequency of 1/10,000 live births caused by hetereozygous pathogenic variants in the MECP2 gene, whose protein participates in the development and differentiation of the central nervous system. This study aimed to describe two cases with Rett syndrome diagnosis, one of them with a new variant of the MECP2 gene. Case reports: We first describe the case of a 5-year-old female with microcephaly and neurodevelopmental regression starting at 3 years old, clinically corresponding to stage III Rett syndrome. Sequencing of the MECP2 gene identified a heterozygous likely pathogenic variant [c.606delC (p.Thr203Argfs*7)] not reported previously. The second case is a 17-year-old female, referred due to severe intellectual disability, clinically found on stage IV. MECP2 sequencing was performed identifying a pathogenic variant previously described [c.880C> T (p.Arg294 *)]. Conclusions: Rett syndrome clinical diagnosis was carried out based on established criteria. MECP2 sequencing confirmed the diagnosis. For neurodevelopmental disorders approach, it is essential to know the phenotype of Rett syndrome and select the molecular tool for the diagnosis. Patients with Rett syndrome require interdisciplinary follow-up for reducing the impact of complications.

Graded and pan-neural disease phenotypes of Rett Syndrome linked with dosage of functional MeCP2

Rett syndrome (RTT) is a progressive neurodevelopmental disorder, mainly caused by mutations in MeCP2 and currently with no cure. We report here that neurons from R106W MeCP2 RTT human iPSCs as well as human embryonic stem cells after MeCP2 knockdown exhibit consistent and long-lasting impairment in maturation as indicated by impaired action potentials and passive membrane properties as well as reduced soma size and spine density. Moreover, RTT-inherent defects in neuronal maturation could be pan-neuronal and occurred in neurons with both dorsal and ventral forebrain features. Knockdown of MeCP2 led to more severe neuronal deficits as compared to RTT iPSC-derived neurons, which appeared to retain partial function. Strikingly, consistent deficits in nuclear size, dendritic complexity and circuitry-dependent spontaneous postsynaptic currents could only be observed in MeCP2 knockdown neurons but not RTT iPSC-derived neurons. Both neuron-intrinsic and circuitry-dependent deficits of MeCP2-deficient neurons could be fully or partially rescued by re-expression of wild type or T158M MeCP2, strengthening the dosage dependency of MeCP2 on disease phenotypes and also the partial function of the mutant. Our findings thus reveal stable neuronal maturation deficits and unexpectedly, graded sensitivities of neuron-inherent and neural transmission phenotypes towards the extent of MeCP2 deficiency, which is informative for future therapeutic development.

Induction of long-term potentiation at Schaffer collateral-CA1 synapses in mice hippocampus after IMPX977 administration / 中草药·英文版

Objective: To investigate the effects of IMPX977 on long term potentiation (LTP) at Schaffer collateral-CA1 synapses in vitro and on methyl CpG binding protein 2 (Mecp2) expression in mice cortex and hippocampus. Methods: Thirty-two C57BL/6 mice were randomly divided into four groups: control, olive oil (vehicle), IMPX977 low (5 mg/kg) and high (15 mg/kg) groups. Mice were administrated every other day orally for two weeks. Extracellular recording technique in vitro was used to record the effects of IMPX977 on Schaffer collateral-CA1 LTP pathway in acute mice hippocampal slices. The Mecp2 protein expression level was detected by Western blotting. Results: Compared to the control group, vehicle did not alter the synaptic transmission in Schaffer collateral-CA1 synapses, however, IMPX977 at concentrations of 5 mg/kg and 15 mg/kg significantly enhanced fEPSP (field excitatory postsynaptic potential) slope in Schaffer collateral-CA1 pathway to (179.6 ± 17.8)% and (191.4 ± 21.4)%, individually 60 min after HFS, IMPX977 improved LTP induction significantly at Schaffer collateral-CA1 pathway at least. Also, IMPX977 significantly elevated MeCP2 protein level in cortex. Conclusion: The effects of IMPX977 on synaptic transmission and Mecp2 protein expression provided convincing evidence that IMPX977 could be promising new drug candidates for Rett syndrome treatment.

Methyl-CpG-binding protein 2 gene mutations and its association with epilepsy: a single centre study from the Indian subcontinent

Rett syndrome (RTT) is an X-linked disorder caused by mutations in MECP2 in majority of cases. It is characterized by arrested development between 6 and 18 months of age, regression of acquired hand skills and speech, stereotypic hand movements, gait abnormalities and seizures. There are a very few studies in India which illustrates mutation spectrum in RTT. None of the studies have correlated seizures with the genotype. This study describes the phenotype and genotype spectrum in children with RTT syndrome and analyses the association of epilepsy with various clinical features and molecular findings. All children with RTT in our cohort had global developmental delay. Genetic diagnosis identified mutations of the MECP2 in all 25 children where RTT was suspected. We have identified point mutations in 20 patients, one insertion and four deletions by Sanger sequencing, namely c.1164_1207 (44 bp), c.1165_1207 (43 bp), c.1157_1197 (41 bp) del and c.1157_1188 (32 bp). Clinically, none of the patients with deletion had seizures. We identified one novel insertion variant c.337_338 (p.S113Ffs*9). All the deletions were located in the C-terminal region. Majority of the mutations (22/25) were identified in exon 4 which comprised of nonsense and missense types. Screening of hotspot mutations in exon 4 should be the first line evaluation in diagnosis of RTT. Molecular testing could help in specific management of seizures in RTT.

Reversal of Social Recognition Deficit in Adult Mice with MECP2 Duplication via Normalization of MeCP2 in the Medial Prefrontal Cortex / 神经科学通报·英文版

Methyl-CpG binding protein 2 (MeCP2) is a basic nuclear protein involved in the regulation of gene expression and microRNA processing. Duplication of MECP2-containing genomic segments causes MECP2 duplication syndrome, a severe neurodevelopmental disorder characterized by intellectual disability, motor dysfunction, heightened anxiety, epilepsy, autistic phenotypes, and early death. Reversal of the abnormal phenotypes in adult mice with MECP2 duplication (MECP2-TG) by normalizing the MeCP2 levels across the whole brain has been demonstrated. However, whether different brain areas or neural circuits contribute to different aspects of the behavioral deficits is still unknown. Here, we found that MECP2-TG mice showed a significant social recognition deficit, and were prone to display aversive-like behaviors, including heightened anxiety-like behaviors and a fear generalization phenotype. In addition, reduced locomotor activity was observed in MECP2-TG mice. However, appetitive behaviors and learning and memory were comparable in MECP2-TG and wild-type mice. Functional magnetic resonance imaging illustrated that the differences between MECP2-TG and wild-type mice were mainly concentrated in brain areas regulating emotion and social behaviors. We used the CRISPR-Cas9 method to restore normal MeCP2 levels in the medial prefrontal cortex (mPFC) and bed nuclei of the stria terminalis (BST) of adult MECP2-TG mice, and found that normalization of MeCP2 levels in the mPFC but not in the BST reversed the social recognition deficit. These data indicate that the mPFC is responsible for the social recognition deficit in the transgenic mice, and provide new insight into potential therapies for MECP2 duplication syndrome.

Rett syndrome: a neurodevelopmental disorder

Rett Syndrome is a rare genetic disorder caused by a mutation on the MECP2 gene on the X chromosome. It classically presents with neuroregression, loss of purposeful hand use, stereotypical involuntary hand wringing movements, an ataxic gait and acquired microcephaly with a large proportion of patients developing seizures. The authors present the case of a 3.5 year old girl with severe global developmental delay and regression, loss of purposeful hand use and an ataxic gait for 2 years and seizures since 5 days along with microcephaly with involuntary hand movements but no classic wringing movements with no significant findings on MRI and EEG and diagnosed with Rett Syndrome on the basis of genetic testing.

Síndrome de Rett: Análisis molecular del gen MECP2 en pacientes chilenas / Rett syndrome: MECP2 gene molecular analysis in Chilean patients

INTRODUCCIÓN: El síndrome de Rett (RTT) es un trastorno neurológico progresivo caracterizado por producir una regresión del desarrollo psicomotor en niñas previamente sanas. La mayoría de los casos son causados por variantes patogénicas en el gen MECP2, que codifica para la proteína methyl CpG- binding protein 2. OBJETIVO: Describir la frecuencia y el tipo de variantes patogénicas en MECP2 en mujeres chilenas con diagnóstico clínico de RTT. PACIENTES Y MÉTODO: Se invitó a participar en este estudio a mujeres chilenas con sospecha clínica de RTT. Se reunió información clínica mediante un cuestionario. Se analizaron variantes patogénicas en MECP2 mediante el método de secuenciación de Sanger y se utilizó Multiple Ligation-dependant Probe Amplification (MLPA) para la detección de duplicaciones y deleciones. RESULTADO: El estudio incluyó 14 pacientes con sospecha de RTT, de las cuales 8 (57%) pacientes tuvieron variantes patogénicas. Las restantes permanecen sin diagnóstico molecular. CONCLUSIÓN: Variantes patogénicas en MECP2 están presentes en pacientes chilenas con RTT. Es probable que haya otros genes o diagnósticos involucrados en las pacientes sin hallazgos en MECP2. A partir de este trabajo, el diagnóstico molecular está disponible en Chile.

INTRODUCTION: Rett syndrome (RTT) is a progressive neurological disorder characterized by regres sion of psychomotor development in previously healthy girls. Most cases are due to pathogenic va riants in the MECP2 gene which encodes for the methyl CpG-binding protein 2. OBJECTIVE: To des cribe the frequency and type of pathogenic variants in the MECP2 gene in Chilean female patients with clinical diagnosis of RTT. PATIENTS AND METHOD: Chilean women with clinical suspicion of RTT were invited to participate in the study. Clinical data were collected through a questionnaire. MECP2 pathogenic variants were analyzed by Sanger sequencing method and Multiplex Ligation-dependent Probe Amplification (MLPA) was used to detect duplications or deletions. RESULTS: The study in cluded 14 patients with suspected RTT, of which eight (57%) patients had pathogenic variants. The other patients remain without molecular diagnosis. CONCLUSIONS: Pathogenic variants in MECP2 are present in Chilean patients with RTT. It is likely that there are other genes or diagnoses involved in patients without MECP2 findings. As of this study, molecular diagnosis is available in Chile.

Effects of puerarin on the expressions of CaM, CaMKⅡ, MECP2, BDNF and Akt in oxygen and glucose deprivation cell models / 西安交通大学学报(医学版)

Objective: To observe the effects of puerarin on the expressions of CaM, CaMKⅡ, BDNF and Akt in vascular dementia cell models induced by oxygen and glucose deprivation (OGD). Methods: The passaged well-differentiated PC12 cells were randomly divided into control group, model group, and low-dose, medium-dose and high-dose intervention groups. Vascular dementia cell model was established by OGD. Suitable OGD time and concentration of puererin were obtained from the cell viability measured by MTT assay. The release of LDH was measured to assess the extent of cell damage and identify cell models. The expressions of CaM, CaMKⅡ, MECP2, BDNF and Akt were detected by Western blot. Results: PC12 cells with OGD prolonged viability decreased in a time-dependent manner, with increased concentrations of puerarin increased in a concentration-dependent manner. Effective intervention of puerarin was 0.1-10 μmol/L and optimal time of OGD was 6 h. Compared with control group, the release of LDH in model group was significantly increased (P0.05). Puerarin could down-regulate the level of CaM protein, increase the expressions of MECP2 and BDNF and the phosphorylation of CaMKⅡ, and also increase the phosphorylation of Akt in addition to the low-dose group (P<0.05). Conclusion: The neuroprotective effect of puerarin may be related to the increase of the autophosphorylation of CaMKⅡ mediated by Ca2+-CaM complex, induce the phosphorylation of MECP2, up-regulate the expression of BDNF and activate the PI3K-Akt pathway to inhibit the expression of apoptotic genes and proteins.

Positive effects of low dose IMPX977 on Rett syndrome related MeCP2 targeted-genes / 中草药·英文版

Objective: To investigate the effect of IMPX977 on MeCP2 targeted-genes and the feasibility of IMPX977 acting as a therapeutic candidate drug for Rett syndrome by genomewide transcription profiling. Methods: Rats’ cortex of control group, IMPX977-treated low-dose group (10 mg/kg), and IMPX977-treated high-dose group (30 mg/kg) were collected and RNA was extracted from the tissues. Then, RNA was subjected to RNA-sequencing. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) were used in functional enrichment analysis of differentially expressed genes. Results: Six MeCP2 targeted-genes were identified in the low/control categories, but not in the high/control categories. Conclusion: Low-dose treatment of IMPX977 (10 mg/kg) showed a positive effect on MeCP2 targeted-genes and it may serve as a drug candidate for Rett syndrome therapy with proper dosage.

Expression and significance of MeCP2 and TH protein in normal SH-SY5Y cells and Parkinson's disease cell model / 国际检验医学杂志

Objective To investigate the expression and significance of TH and MeCP2 protein in normal SH-SY5Y cells and Parkinson's disease cell model.Methods The experiment was divided into 3 groups:blank control group,non transfection;model control group;pEGFP-N1-MeCP2 group,transfection solution added to the recombinant pEGFP-N1-MeCP2 plasmid.In addition to the blank group,the remaining two groups were added 50.0 μmol/L 6-OHDA treatment for 24 hours.CCK-8 assay and flow cytometry were used to detect cell activity and apoptosis in normal SH-SY5Y cells and the SH-SY5Y cell with up-regulation of MeCP2 induced by 6-OHDA.Immunofluorescence and Western blot analysis were used to detect the changes of MeCP2 protein and TH protein expression in each group of SH-SY5Y cells.Results As for the cell survival and apoptosis of SH-SY5Y cells detected by CCK-8 assay and induced 6-OHDA of flow cytometry and SH-SY5Y cells with up-regulation of MeCP2 in model control group,compared to those in pEGFP-N1-MeCP2 group and the thank control group,the difference was statistically significant (P＜0.05).The expression of MeCP2 and TH in SH-SY5Y induced 6-OHDA cells was detected by double immunofluorescence,it was found that in model control group,with 6-OHDA (50.0 μmol/L) inducing for 24 hours,and the expression of MeCP2 and TH decreased significantly (P＜0.05).After Western blot was used to detect the up-regulation of MeCP2 expression,in 6-OHDA induced SH-SY5Y cells of MeCP2 and TH expression,the expression of MeCP2 and TH protein in pEGFP-N1-MeCP2 group and blank control group was statistically different from that in model control group (P＜0.01).Conclusion The transfection of pEGFP-N1-MeCP2 recombinant plasmid could inhibit the apoptosis of SH-SY5Y cells induced by 6-OHDA,improve the expression of TH and increase the cell survival rate.

Updates on pathogenesis-related genes and diagnosis and treatment of Rett syndrome / 国际儿科学杂志

Rett syndrome ( RTT) is a devastating neurological disorder that is caused largely by muta-tions in the X-linked gene MECP2,other two genes associated with RTT are CDKL5 and FOXG1. RTT is one of the most common causes of mental retardation in girls,male cases are rare. Classical features of typical RTT in-clude losing acquired spoken language and hand skills,hand stereotypies,epilepsy and respiratory disorders. The diagnosis of RTT mainly depends on the clinical characteristics. Atpresent, it still lacks atargeted treatment. In this review,we summarize both the gene research,diagnosis and treatmentprogresses of RTT so as to improve the understanding of RTT.

Anesthetic management of a pediatric patient with Rett syndrome: A case report

Rett syndrome is a neurodevelopmental disease that almost always affects female patients. It is caused by mutations in MeCP2 in the majority of cases. Patients diagnosed with Rett syndrome may experience serious adverse events even with smaller amounts of medication for sedation and anesthesia. The major anesthetic concerns associated with Rett syndrome are lack of cooperation, abnormal continuous limb movements, abnormal respiratory control, difficult positioning secondary to scoliosis, and altered sensitivity to painful stimuli. Because of the risks caused by these problems, anesthesiologists should be aware of the specific anesthetic concerns of patients with Rett syndrome in order to safely administer anesthesia. Here, we describe the management of a pediatric patient diagnosed with Rett syndrome.

Striatal Inhibition of MeCP2 or TSC1 Produces Sociability Deficits and Repetitive Behaviors

Autism spectrum disorder (ASD) is a heterogeneous group of neurobehavioral disorders characterized by the two core domains of behavioral deficits, including sociability deficits and stereotyped repetitive behaviors. It is not clear whether the core symptoms of ASD are produced by dysfunction of the overall neural network of the brain or that of a limited brain region. Recent studies reported that excessive glutamatergic or dopaminergic inputs in the dorsal striatum induced sociability deficits and repetitive behaviors. These findings suggest that the dorsal striatum plays a crucial role in autistic-like behaviors. The present study addresses whether functional deficits of well-known ASD-related genes in the dorsal striatum also produce ASD core symptoms. This study also examines whether these behavioral changes can be modulated by rebalancing glutamate and/or dopamine receptor activity in the dorsal striatum. First, we found that the siRNA-mediated inhibition of Shank3, Nlgn3, Fmr1, Mecp2, or Tsc1 in the dorsal striatum produced mild to severe behavioral changes in sociability, cognition, and/or repetitive behaviors. The knockdown effects of Mecp2 and Tsc1 on behavioral changes were the most prominent. Next, we demonstrated that behavioral changes induced by striatal inhibition of MeCP2 and TSC1 were rescued by D-cycloserine (an NMDA agonist), fenobam (an mGluR5 antagonist), SCH23390 (a D1 antagonist), and/or ecopipam (a D1 partial antagonist), pharmacological drugs that are known to regulate ASD-like symptoms in animal models. Collectively, these results suggest that the dorsal striatum is a critical brain region that, when dysfunctional, produces the core symptoms of ASD.

Síndrome de Rett: revisión de la literatura con primeros casos reportados en Colombia con caracterización clínica y molecular / Rett syndrome: review of the literature and first cases reported in Colombia with clinical characterization and molecular diagnosis

RESUMEN INTRODUCCIÓN: El síndrome de Rett es una condición neurológica severa y la segunda causa genética de retraso mental profundo en mujeres. Se genera por mutaciones en el gen MECP2 y es caracterizada por una pérdida de las ganancias psicomotoras, con una prevalencia general estimada de 1:10.000 niñas, según la extrapolación de algunos estudios europeos. OBJETIVOS: Realizar una revisión de la literatura sobre el síndrome de Rett y presentar una serie de casos diagnosticados en Colombia por clínica y prueba molecular. METODOLOGÍA: Se efectuó una búsqueda bibliográfica y de reportes de casos en 21 bases de datos internacionales, más de 14 revistas del área de la salud y dos motores de búsqueda generales entre 2014 y 2016. Los casos presentados fueron seleccionados de la consulta de genética médica realizada por los autores. HALLAZGOS: No se encontró ningún caso colombiano de síndrome de Rett, ni confirmado con prueba molecular en Latinoamérica. Se reporta así la primera serie de casos nacional y la mayor latinoamericana, conformada por siete pacientes con tipo clásico y tres atípicos, todas con diagnóstico molecular. CONCLUSIONES: Pese a tener una evolución clínica caracterizada, su baja prevalencia y amplio espectro clínico convierten al síndrome de Rett en un reto diagnóstico y terapéutico. La mutación c.749_750insT se reporta por primera vez, la c.473C>G por segunda en la literatura y la c.763C>T se presenta en dos pacientes con fenotipos totalmente distintos, lo que confirma la no correlación genotipo-fenotipo de la enfermedad.

SUMMARY INTRODUCTION: Rett Syndrome is a severe neurological condition and the second genetic cause of profound mental retardation in women. It is generated by mutations in the MECP2 gene and it is characterized by a loss of psychomotor gains, with an estimated overall prevalence of 1:10,000 girls, according to the extrapolation of some European studies. Objectives. To make a review of Rett Syndrome and to present a series of cases diagnosed in Colombia by clinical criteria and molecular tests. METHODOLOGY: We made a bibliographic research in 21 international databases, more than 14 health journals and two general search engines between 2014 and 2016. The cases presented were selected from the Medical Genetics consultation carried out by the authors. FINDINGS: No Colombian case of Rett Syndrome was found nor confirmed with molecular testing in Latin America. We report the first cases in Colombia and the largest in Latin America, consisting of seven patients with classic type and three with atypical type, all with molecular diagnosis. CONCLUSIONS: In spite of having a characterized clinical evolution, its low prevalence and broad clinical spectrum, make Rett Syndrome a diagnostic and therapeutic challenge. We report for the first time the mutation c.749_750insT, the c.473C> G for second time in the literature and the c.763C> T is presented in two patients with totally different phenotypes, confirming the non-correlation genotype-phenotype of the disease.

Comprehensive Evaluation on Effect of IMPX977 on Expression of Methyl-CpG-binding Protein 2 in Rats / 中草药·英文版

Objective To investigate the effect of IMPX977 on methyl-CpG-binding protein 2 (MeCP2) expression in rats. Methods Forty-eight SD rats were randomly divided into four groups: normal control group, olive oil (negative control, 5 mL/kg oil) group, and 10 mg/kg and 30 mg/kg IMPX977 administration groups. All rats were given corresponding dose of drugs each other day and administered orally for two weeks. Tissues including cortex and cerebellum were collected from rats to assay the expression of MeCP2 by quantitative RT-PCR and Western blotting. Results The IMPX977 supplement showed no significant effect on the body weight of rats. In normal rats, MeCP2 was highly expressed in cerebellum, cortex and hippocampus, and less expressed in heart, spleen and lung. In addition to male rats, compared with the control group, the expression of MeCP2 mRNA was significantly increased in cerebellum after 30 mg/kg IMPX977 treatment and contrarily, absolutely decreased in cortex of all treatment groups. Furthermore, in female rats MeCP2 mRNA was reduced in cortex of both olive oil and 30 mg/kg IMPX977 treatment groups compared with control group. Meanwhile, MeCP2 protein level was significantly elevated in cerebellum of treated male rats compared to the control group. In contrast to the control group, the expression of MeCP2 protein in both cerebellum and cortex of female rats in other three groups was increased. Conclusion IMPX977 treatment (10 mg/kg) may elevate the expression of MeCP2, which establishes experimental foundation for the further research on rat models of Rett syndrome.