Project description:Turnover and exchange of nucleosomal histones and their variants, a process long believed to be static in post-replicative cells, remains largely unexplored in brain. Here, we describe a novel mechanistic role for HIRA (histone cell cycle regulator) and proteasomal degradation associated histone dynamics in the regulation of activity-dependent transcription, synaptic connectivity and behavior. We uncover a dramatic developmental profile of nucleosome occupancy across the lifespan of both rodents and humans, with the histone variant H3.3 accumulating to near saturating levels throughout the neuronal genome by mid-adolescence. Despite such accumulation, H3.3 containing nucleosomes remain highly dynamic–in a modification independent manner–to control neuronal- and glial- specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical, and previously undocumented, regulator of cell-type specific transcription and plasticity in mammalian brain. All RNA-seq samples were generated to test the impact of neuronal activity/adult physiological plasticity on histone turnover turnover mediated alterations in mRNA expression in the central nervous system. This was tested in cultured neurons and astrocytes, and embryonic/adult brain tissues
Project description:Turnover and exchange of nucleosomal histones and their variants, a process long believed to be static in post-replicative cells, remains largely unexplored in brain. Here, we describe a novel mechanistic role for HIRA (histone cell cycle regulator) and proteasomal degradation associated histone dynamics in the regulation of activity-dependent transcription, synaptic connectivity and behavior. We uncover a dramatic developmental profile of nucleosome occupancy across the lifespan of both rodents and humans, with the histone variant H3.3 accumulating to near saturating levels throughout the neuronal genome by mid-adolescence. Despite such accumulation, H3.3 containing nucleosomes remain highly dynamic–in a modification independent manner–to control neuronal- and glial- specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical, and previously undocumented, regulator of cell-type specific transcription and plasticity in mammalian brain. All ChIP-seq samples were generated to test the impact of neuronal activity/adult physiological plasticity on histone turnover in the central nervous system. This was tested in cultured neurons and astrocytes, FACS purified neurons or FACS purified Glia.
Project description:Turnover and exchange of nucleosomal histones and their variants, a process long believed to be static in post-replicative cells, remains largely unexplored in brain. Here, we describe a novel mechanistic role for HIRA (histone cell cycle regulator) and proteasomal degradation associated histone dynamics in the regulation of activity-dependent transcription, synaptic connectivity and behavior. We uncover a dramatic developmental profile of nucleosome occupancy across the lifespan of both rodents and humans, with the histone variant H3.3 accumulating to near saturating levels throughout the neuronal genome by mid-adolescence. Despite such accumulation, H3.3 containing nucleosomes remain highly dynamic–in a modification independent manner–to control neuronal- and glial- specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical, and previously undocumented, regulator of cell-type specific transcription and plasticity in mammalian brain.
Project description:Turnover and exchange of nucleosomal histones and their variants, a process long believed to be static in post-replicative cells, remains largely unexplored in brain. Here, we describe a novel mechanistic role for HIRA (histone cell cycle regulator) and proteasomal degradation associated histone dynamics in the regulation of activity-dependent transcription, synaptic connectivity and behavior. We uncover a dramatic developmental profile of nucleosome occupancy across the lifespan of both rodents and humans, with the histone variant H3.3 accumulating to near saturating levels throughout the neuronal genome by mid-adolescence. Despite such accumulation, H3.3 containing nucleosomes remain highly dynamic–in a modification independent manner–to control neuronal- and glial- specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical, and previously undocumented, regulator of cell-type specific transcription and plasticity in mammalian brain.
Project description:Histones were isolated from brown adipose tissue and liver from mice housed at 28, 22, or 8 C. Quantitative top- or middle-down approaches were used to quantitate histone H4 and H3.2 proteoforms. See published article for complimentary RNA-seq and RRBS datasets.
Project description:Brain-Derived Neurotrophic Factor (BDNF) is crucial for neuronal survival, differentiation, synaptic plasticity, memory formation, and neurocognitive health. Molecular mechanisms of BDNF promoting cellular survival and synaptic plasticity have been intensely studied, yet its role in genome regulation is obscure. Using human induced pluripotent stem cell (hiPSC)-derived neurons via lentiviral delivery of the neuronal transcription factor Ngn2, we performed a temporal profiling (1h, 6h and 10h) of chromatin accessibility upon BDNF treatment or depolarization (KCl) to identify BDNF-specific chromatin-to-gene expression programs.
Project description:Brain-Derived Neurotrophic Factor (BDNF) is crucial for neuronal survival, differentiation, synaptic plasticity, memory formation, and neurocognitive health. Molecular mechanisms of BDNF promoting cellular survival and synaptic plasticity have been intensely studied, yet its role in genome regulation is obscure. Using human induced pluripotent stem cell (hiPSC)-derived neurons via lentiviral delivery of the neuronal transcription factor Ngn2, we performed a temporal profiling (1h, 6h and 10h) of chromatin accessibility upon BDNF treatment or depolarization (KCl) to identify BDNF-specific chromatin-to-gene expression programs.
Project description:<p>RNA sequencing was performed on human DRGs and relative gene abundances were calculated.</p> <p>Various analyses were performed:</p> <p> <ol> <li>Human DRG gene expression profiles were contrasted with a panel of gene expression profiles of relevant tissues in human and mouse ( integrating, among other sources, datasets from ENCODE and GTex ) in order to identify.</li> <ol type="a"> <li>DRG-enriched gene expression, co-expression modules of DRG-expressed genes, and key transcriptional regulators in humans.</li> <li>Contrasting the human and mouse DRG transcriptomes to identify DRG-enriched gene expression patterns that were conserved between human and mouse, identifying putative cell types of expression of these genes, and potential known drugs that might target the corresponding gene products.</li> <li>Characterization of non-coding RNA profile of human and mouse DRGs.</li> <li>Characterization of DRG-enriched alternative splicing and alternative transcription start site usage based transcript variants in humans and mouse, and the overlap between these two species.</li> <li>Contrasting of human DRG and GTex human tibial nerve samples to identify putative axonally transported mRNAs in sensory neurons.</li> </ol> <li>Human DRG transcriptomes from donors suffering from neuropathic and/or chronic pain were contrasted with controls to identify.</li> <ol type="a"> <li>Differentially expressed genes, pathways and regulators path play a potential role in neuronal plasticity, electrophysiological activity, immune signaling and response.</li> <li>Predictive models (Random Forests) were built to jointly predict the sex and pain state of samples based on information contained solely in autosomal gene expression profile.</li> <li>Gene co-expression modules were identified and gene set enrichment analysis performed.to identify sample - pathway associations, and to broadly characterize plasticity in human DRG cell types.</li> </ol> </ol> </p>