Project description:To examine potential differences in activity-dependent gene expression, we analyzed mRNA expression in cultured neurons isolated from Wild-type vs MeCP2 S421A mice at 0 (unstimulated), 1 or 6 hours after membrane depolarization by exposure to high extracellular KCl (55mM) All mice were male littermates from one of three litters. We isolated RNA from dissociated cortical cultures (E16+7DIV) isolated from Wild-Type or MeCP2 S421A knock-in mice littermates. Cells were either left unstimulated or depolarized for 1 or 6 hours by addition of 55mM KCl to the media. mRNA expression was analyzed using the Affymetrix GeneChip Mouse Expression Set 430 2.0 microarray platform.
Project description:Methyl-CpG-binding protein 2 (MECP2) is a transcriptional regulator critical for synaptic function. Dysfunction of synapses, in turn, as well as microglia-mediated neuroinflammation belong to the earliest pathological events in Alzheimer’s disease (AD). Functional versatility of MECP2, including its affinity for different binding partners, transcriptional regulation of different gene sets, and effects on neuronal plasticity, are modulated by post-translational modifications, such as phosphorylation. To characterize expression changes through blocking of MECP2 S80 and S423 phosphorylation in neuron-BV2 co-cultures upon induction of neuroinflammation, mouse primary cortical neurons were transduced with MECP2-WT and MECP2-S80A and MECP2-S423A phopsho-variants. Neuroinflammation was induced with LPS/IFNγ and the samples were subjected to RNA sequencing. In neurons co-cultured with BV2 cells, blocking of MECP2 S423 phosphorylation increased the expression of several genes important for neuron and synapse maintenance and protection upon inflammatory stress conditions. Blocking of S80 phosphorylation did not lead to major global expression changes.The results suggest that MECP2 S423 phosphorylation might play a role in activation of neuronal gene expression conveying neuroprotection under neuroinflammation related stress conditions.
Project description:This dataset comprises 15 raw AP-MS files, each with an associated peak list, captured using a Vanquish Neo nanoLC system in tandem with an Orbitrap Eclipse mass spectrometer. To generate MECP2 hESC-reporter lines for wild type (WT) and various mutations of MECP2, including R133C, R168X, and R270X, we first used CRISPR/Cas9 to create MECP2 alleles carrying the green fluorescent protein (GFP) sequences in the endogenous gene. The R133C mutation was then introduced into the WT MECP2-GFP reporter line. Mutations R133C, R168X, and R270X are recognized as loss-of-function variants in MECP2 and are also identified as primary Rett syndrome-causing mutations. For efficient neuronal differentiation, a doxycycline (DOX)-responsive NGN2 construct was incorporated at their AAVS1 safe harbor locus. Upon the addition of DOX, homogenous populations of neurons were generated within three weeks from those four MECP2 hESC-reporter lines. Subsequently, GFP-pull down assay and AP-MS were performed using these WT MECP2-GFP neurons along with R133C-, R168X-, and R270X-mutant MECP2-GFP reporter neurons. Neurons expressing only the GFP tag served as a negative control. AP-MS analysis identified proteins interacting differently between WT and mutant MECP2 within human neurons.
Project description:Rett syndrome (RTT; OMIM#312750) is a rare devastating neurodevelopmental disorder that represents the most common genetic cause of severe intellectual disability in girls. Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene have been reported in over 95% cases of classical forms of RTT. Although initial studies supported a role for MeCP2 exclusively in neurons, recent data indicate a function also in astrocytes, which emerged as critical players involved in RTT pathogenesis through non-cell autonomous effects. Indeed, Mecp2 knock-out (KO) astrocytes cannot properly support neuronal maturation of wilt-type (WT) neurons and our data demonstrated a detrimental effect also on synaptogenesis and synaptic maintainence. Nevertheless, the molecular mechanisms by which RTT astrocytes can impact on neuronal health remains unknown. In comparison to previous studies exploring the transcriptomic and proteomic profiles of KO astrocytes per se, we used an indirect strategy to unveil the molecular mechanisms responsible for their negative action on neurons. We thus analysed the molecular pathways deregulated in WT neurons cultivated under the influence of KO (n=8) versus WT (n=7) astrocytes, in a transwell-based co-culture system, that allows the exchange of paracrine signals preventing cell-to-cell contact. Astrocytes were seeded on transwell inserts and transferred on neurons at Div0; the co-cultures were maintained until Div14. WT cortical neurons cultivated alone were also included (n=5).
Project description:Duplication or deficiency of the X-linked MECP2 gene reliably produces profound neurodevelopmental impairment. MECP2 mutations are almost universally responsible for Rett syndrome (RTT), and particular mutations and cellular mosaicism of MECP2 may underlie the spectrum of RTT symptomatic severity. No clinically approved treatments for RTT are currently available, but human pluripotent stem cell technology offers a platform to identify neuropathology and test candidate therapeutics. Using a strategic series of increasingly complex human stem cell-derived technologies, including human neurons, MECP2-mosaic neurospheres to model RTT female brain mosaicism, and cortical organoids, we identified synaptic dysregulation downstream from knockout of MECP2 and screened select pharmacological compounds for their ability to treat this dysfunction. Two lead compounds, Nefiracetam and PHA 543613, specifically reversed MECP2-knockout cytologic neuropathology. The capacity of these compounds to reverse neuropathologic phenotypes and networks in human models supports clinical studies for neurodevelopmental disorders in which MeCP2 deficiency is the predominant etiology.
Project description:To examine potential differences in activity-dependent gene expression, we analyzed mRNA expression in cultured neurons isolated from Wild-type vs MeCP2 S421A mice at 0 (unstimulated), 1 or 6 hours after membrane depolarization by exposure to high extracellular KCl (55mM) All mice were male littermates from one of three litters.
