Project description:We report the application for high-throughput profiling of transcriptome, chromatin-associated proteins and histone-modifications on a genome-wide level in iPSC-derived family control astrocytes vs LFS (Li-Fraumeni Syndrome) patient astrocytes.
Project description:DNA methylation dynamics influence brain function and are altered in neurological disorders. 5-hydroxymethylcytosine (5-hmC), a DNA base derived from 5-methylcytosine (5mC) accounts for ~40% of modified cytosine in brain, and has been implicated in DNA methylation-related plasticity. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. We find developmentally programmed acquisition of 5-hmC in neuronal cells. Epigenomic localization of 5-hmC-regulated regions reveals stable and dynamically modified loci during neurodevelopment and aging. By profiling 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by finding that its levels are inversely correlated with methyl-CpG-binding protein 2 (Mecp2) dosage, a protein encoded by a gene in which mutations cause Rett Syndrome. These data point toward critical roles for 5-hmC-mediated epigenetic modification in neurodevelopment and diseases. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. Profiling of 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by profiling 5-hmC in mouse cerebellum lacking MeCP2, a protein encoded by a gene in which mutations cause Rett Syndrome.
Project description:The Shank3 gene encodes the major postsynaptic scaffolding protein SHANK3. Its mutation causes a syndromic form of autism spectrum disorder (ASD): Phelan-McDermid Syndrome (PMDS). It is characterized by global developmental delay, intellectual disorders (ID), ASD behavior, affective symptoms, as well as extra-cerebral symptoms. Although Shank3 deficiency causes a variety of molecular alterations, they do not suffice to explain all clinical aspects of this heterogenic syndrome. Since global gene expression alterations in Shank3 deficiency remain inadequately studied, we explored the transcriptome in vitro in primary hippocampal cells from Shank3∆11(-/-) mice, under control and lithium (Li) treatment conditions, and confirmed the findings in vivo. The Shank3∆11(-/-) genotype affected the overall transcriptome. Remarkably, extracellular matrix (ECM) and cell cycle transcriptional programs were disrupted. Accordingly, in the hippocampi of adolescent Shank3∆11(-/-) mice we found proteins of the collagen family and core cell cycle proteins downregulated. In vitro Li treatment of Shank3∆11(-/-) cells had a rescue-like effect on the ECM and cell cycle gene sets. Reversed ECM gene sets were part of a network, regulated by common transcription factors (TF) such as cAMP responsive element binding protein 1 (CREB1) and β-Catenin (CTNNB1), which are known downstream effectors of synaptic activity and targets of Li. These TFs were less abundant and/or hypo-phosphorylated in hippocampi of Shank3∆11(-/-) mice and could be rescued with Li in vitro and in vivo. Our investigations suggest the ECM compartment and cell cycle genes as new players in the pathophysiology of Shank3 deficiency, and imply involvement of transcriptional regulators, which can be modulated by Li. This work supports Li as potential drug in the management of PMDS symptoms, where a Phase II study is ongoing.
Project description:Multiple family members with cancer or individuals with multiple primary cancers are indicative of potential genetic etiology1. Germline mutations in TP53 cause a rare high penetrance cancer syndrome, Li Fraumeni Syndrome (LFS)2. We identified a TP53 tetramerization domain (TD) missense mutation c.1000G>C;p.G334R, in a family with LFS-associated cancers. Twenty-one additional probands were identified, and available tumors showed biallelic somatic inactivation of TP53. The majority of families were of Ashkenazi Jewish descent, and the TP53 c.1000G>C allele was found on a commonly inherited haplotype. While classical p53 target gene activation was maintained in p.G334R mutant cell lines treated with Nutlin-3a, a subset of p53 target genes, including PCLO, PLTP, PLXNB3 and LCN15, showed defective transactivation. Structural analysis demonstrated thermal instability of the mutant TD, and the G334R mutant protein showed increased preponderance of mutant conformation protein. TP53 c.1000G>C;p.G334R is a rare AJ-predominant mutation associated with low penetrance Li-Fraumeni Syndrome
Project description:Translation of many transcripts is highly regulated in the developing brain, and disturbance of translational regulation machinery contributes to neurodevelopmental disorders. In neural progenitor cells, for example, several critical pro-differentiation genes are transcribed, but their translation is repressed to allow rapid translation when appropriate signals to differentiate are received. This layer of translational regulation makes it challenging to directly correlate RNA and protein levels in stem cells and neurons. During early neural development, translation is regulated by several pathways that can impact neuron fate and function. The mTOR-mediated signaling pathway plays a crucial role in the induction of neuron differentiation, axon and dendrite development, and gliogenesis, while being key in the maintenance of pluripotent and neural stem cells {Wang:2013hg}{Agrawal:2014ek}{Ka:2014fq}. Dysregulation of the translation repressor eIF4E-binding protein 2 (4EBP2), a downstream target of mTORC1, leads to an increased ratio of excitatory to inhibitory synaptic inputs and autistic-like behaviors {Gkogkas:2013fh}. The Fragile X Mental Retardation Protein (FMRP), which is encoded by the FMR1 gene {Verkerk:1991hu}, is an RNA binding protein (RBP) that regulates translation through multiple mechanisms {Richter:2015ii}. Loss of expression of FMR1 causes Fragile X Syndrome (FXS), the most common inherited intellectual disability as well as the most prevalent single-gene cause of autism spectrum disorder (ASD). FMRP typically functions as a translational repressor {Li:2001ds} and some studies suggest that FXS results from an inability of neurons to achieve regulated local translation, particularly in response to stimuli {Richter:2015ii}. This suggests important roles for control of translation in stem cells and neurons, and an association with significant risk for neurodevelopmental disorders.
Project description:Eukaryotic cells maintain proteostasis through mechanisms that require cytoplasmic and mitochondrial translation. Genetic defects affecting cytoplasmic translation perturb synapse development, neurotransmission, and are causative of neurodevelopmental disorders such as Fragile X syndrome. In contrast, there is little indication that mitochondrial proteostasis, either in the form of mitochondrial protein translation and/or degradation, is required for synapse development and function. Here we focus on two genes deleted in a recurrent copy number variation causing neurodevelopmental disorders, the 22q11.2 microdeletion syndrome. We demonstrate that SLC25A1 and MRPL40, two genes present in the microdeleted segment and whose products localize to mitochondria, interact and are necessary for mitochondrial ribosomal integrity and proteostasis. Our Drosophila studies show that mitochondrial ribosome function is necessary for synapse neurodevelopment, function, and behavior. We propose that mitochondrial proteostasis perturbations, either by genetic or environmental factors, are a pathogenic mechanism for neurodevelopmental disorders.
Project description:While psychiatric disorders (e.g., schizophrenia) and autism spectrum disorders (ASD) are typically associated with a deficit in social behavior, the opposite trait of hypersociability is exhibited by individuals with specific neurodevelopmental disorders, e.g., Angelman Syndrome (AS) and Williams-Beuren Syndrome (WBS). We have recently reported that the deletion of the miR379-410 cluster in mice led to hypersocial behavior. To study the roles of this miRNA cluster in the context of WBS, we sent for smallRNA sequencing RNA isolated from isogenic human iPSC-derived neurons harboring a deletion present in Williams-Beuren-Syndrome patients (7q11.23). Specifically, we found that members of the miR379-410 cluster were strikingly overrepresented among downregulated miRNAs in iNeurons harboring a deletion of the WBS critical region. Thus, we obtained the first evidence for the pathophysiological significance of the miR379-410 miRNA cluster in the context of WBS. We conclude that targeting this novel pathway could have therapeutic potential for WBS and other neurodevelopmental conditions characterized by social impairments.