Project description:Microarrays were used to identify the differentially expressed genes in the hippocampus of control and Noonan syndrom mice at basal state and in response to 4AP-Bic stimulation (10 min). Functional analysis was performed to determine the biological significance of the data.
Project description:Activity-dependent gene expression is central for sculpting neuronal connectivity in the brain. Despite the importance for synaptic plasticity, a comprehensive analysis of the temporal changes in the transcriptomic response to neuronal activity is lacking. In a genome wide survey we identified genes that were induced at 1, 4, 8, or 24 hours following neuronal activity in the hippocampus. 3 month old male mice were injected with kainic acid or isotonic saline solution. Animals were sacrificed by cervical luxation 1, 2, 4, 8, or 24 h after onset of the first seizure, and RNA was extracted from the hippocampal region.
Project description:Neuronal activity causes the rapid expression of immediate early genes that are crucial for experience driven changes to synapses, learning, and memory. Here, using both molecular and genome-wide next generation sequencing methods, we report that neuronal activity stimulation triggers the formation of DNA double strand breaks (DSBs) in the promoters of a subset of early-response genes, including Fos, Npas4, and Egr1. Generation of targeted DNA DSBs within Fos and Npas4 promoters is sufficient to induce their expression even in the absence of an external stimulus. Activity-dependent DSB formation is likely mediated by the type II topoisomerase, Topoisomerase IIb (Topo IIb), and knockdown of Topo IIb attenuates both DSB formation and early response gene expression following neuronal stimulation. Our results suggest that DSB formation is a physiological event that rapidly resolves topological constraints to early-response gene expression in neurons. Generation of sequencing data from ChIP-seq with antibodies against γH2AX and Topo IIβ after neuronal activity stimulation, and RNA-seq after etoposide treatment
Project description:Analysis of alterations in the hippocampus transcriptome caused by deletion of Mitogen Stress activated Kinase 1 (MSK1). MAPK signaling has been implicated in a wide range of neuronal processes, including development, plasticity and viability. One of the principal downstream targets of both the ERK/MAPK pathway and the p38 MAPK pathway is Mitogen Stress activated Kinase 1 (MSK1). Here, we sought to understand the role that MSK1 plays in neuroprotection against excitotoxic stimulation in the hippocampus. To this end, we utilized a MSK1 null mouse line, cell viability assays and array-based profiling approaches. Here we show that MSK1 is broadly expressed within the major neuronal cell layers of the hippocampus and that status epilepticus (SE) drives acute induction of MSK1 activation. In response to the SE paradigm, MSK1 KO mice exhibited a striking increase in vulnerability to pilocarpine-evoked cell death within the CA1 and CA3 cell layers. Further, cultured MSK1 null neurons exhibited a heighted level of NMDA-evoked excitotoxicity relative to WT neurons, as assessed using the LDH assay. Given these findings, we examined the hippocampal transcriptional profile of MSK1 null mice. Affymetrix array profiling revealed that with MSK1 deletion a total of 115 genes showed significant changes (> 1.25-fold) in expression. Notably, functional analysis indicated that a subset of these genes contribute to neuroprotective signaling networks. Together, these data provide important new insights into the mechanism by which the MAPK/MSK1 signaling cassette confers neuroprotection against excitotoxic insults. Approaches designed to upregulate or mimic the functional effects of MSK1 may prove beneficial against an array of degenerative processes resulting from excitotoxic insults. MAPK signaling has been implicated in a wide range of neuronal processes, including development, plasticity and viability. One of the principal downstream targets of both the ERK/MAPK pathway and the p38 MAPK pathway is Mitogen Stress activated Kinase 1 (MSK1). Here, we sought to understand the role that MSK1 plays in neuroprotection against excitotoxic stimulation in the hippocampus. To this end, we utilized a MSK1 null mouse line, cell viability assays and array-based profiling approaches. Here we show that MSK1 is broadly expressed within the major neuronal cell layers of the hippocampus and that status epilepticus (SE) drives acute induction of MSK1 activation. In response to the SE paradigm, MSK1 KO mice exhibited a striking increase in vulnerability to pilocarpine-evoked cell death within the CA1 and CA3 cell layers. Further, cultured MSK1 null neurons exhibited a heighted level of NMDA-evoked excitotoxicity relative to WT neurons, as assessed using the LDH assay. Given these findings, we examined the hippocampal transcriptional profile of MSK1 null mice. Affymetrix array profiling revealed that with MSK1 deletion a total of 115 genes showed significant changes (> 1.25-fold) in expression. Notably, functional analysis indicated that a subset of these genes contribute to neuroprotective signaling networks. Together, these data provide important new insights into the mechanism by which the MAPK/MSK1 signaling cassette confers neuroprotection against excitotoxic insults. Approaches designed to upregulate or mimic the functional effects of MSK1 may prove beneficial against an array of degenerative processes resulting from excitotoxic insults.
Project description:Activity-dependent gene expression is central for sculpting neuronal connectivity in the brain. Despite the importance for synaptic plasticity, a comprehensive analysis of the temporal changes in the transcriptomic response to neuronal activity is lacking. In a genome wide survey we identified genes that were induced at 1, 4, 8, or 24 hours following neuronal activity in the hippocampus.
Project description:The caspase cleaved form of the tyrosine kinase Lyn (LynDeltaN) mediates a psoriasis-like inflammatory syndrome in mice. To gain insights into the molecular mechanism of LynDeltaN in the control of this infllammatory process, we performed the pangenomic profile of WT and LynDN skin from 5 day-old mice just before the entire inflammatory syndrom takes place.