Project description:Bryant-Li-Bhoj syndrome (BLBS) is a mixed neurodevelopmental/neurodegenerative syndrome caused by germline variants in the genes encoding Histone 3.3 (H3.3). Here, we assess DNA methylation differences between BLBS patient-derived and unaffected control tissues (dermal fibroblasts and blood samples) using the Illumina EPICv2 methylation microarray. Our 8 dermal fibroblast samples and 12 blood samples represent 19 of the 70 unique causative BLBS variants. After multiple testing correction, no CpG probes showed statistically significant methylation differences in either of these tissues. The lack of significant DNA methylation changes identified at this time in BLBS supports evaluation of other causes of dysregulation, as well as re-evaluation for more subtle methylation changes when more samples become available.
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: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: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: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