Project description:Alcoholism is a complex neurological disorder characterized by loss of control in limiting intake, and progressive compulsion to seek and consume ethanol. Prior studies have suggested that the characteristic behaviors associated with escalation of drug use are caused, at least in part, by ethanol-evoked changes in gene expression affecting synaptic plasticity. Implicit in this hypothesis is a dependence on new protein synthesis and remodeling at the synapse. It is well established that mRNA can be transported to neuronal distal processes, where it can undergo localized translation that is regulated in a spatially restricted manner in response to stimulation. It is unknown whether such modulation of the synaptic transcriptome might contribute to ethanol-induced synaptic plasticity. Using ethanol-induced behavioral sensitization as a model of neuroplasticity, here we investigated whether repeated exposure to ethanol altered the synaptic transcriptome, contributing to synaptic plasticity underlying a subsequent increase in the ethanol-evoked locomotor response. A synaptoneurosome preparation was utilized to enrich for RNAs trafficked to the synapse versus the proximal cellular fraction. Two complementary methods of genomic profiling, RNA-Seq and microarrays, were used to survey the synaptic transcriptome of DBA/2J mice subjected to ethanol-induced behavioral sensitization. Strikingly, a large number of genes regulated by acute ethanol showed adaptation to repeated ethanol exposure with sensitization. Genomic profiling showed distinct functional classes in RNA found to be enriched in the synaptoneurosome faction, consistent with their role in synaptic function. A subset of ethanol-responsive genes significantly enriched at the synapse were related to biological functions such as protein folding and extra-cellular matrix components, suggesting a role for local regulation of synaptic protein function by ethanol. In contrast, RNA classes regulated by ethanol in the cell soma included an over-abundance of RNA-binding and trafficking proteins, perhaps reflecting increased demand for dendritic RNA localization. These experiments document that both acute and repeated ethanol produce specific alterations in the complement of RNA at the synapse and lay the foundation for further investigations into the role of the synaptic transcriptome in behavioral adaptations to ethanol. 24 samples were analyzed from 3 treatment groups and 2 cell fractions with 4 biological replicates for each treatment/cell fraction.Cell fractionation was carried out on tissue from a frontal pole dissection of DBA2/J mice, isolating a cytosolic (S2) and synaptoneurosomal (P2) fraction. Treatment groups describe chronic treatment (10 daily injections) and treatment used on test day (single injeciion), producing saline-saline (SS), saline-ethanol (SE) and ethanol-ethanol (EE) groups. Analysis of RNA-seq compared similar treatments across cell fractions or different treatments within a cell fraction.

Project description:Alcoholism is a complex neurological disorder characterized by loss of control in limiting intake, and progressive compulsion to seek and consume ethanol. Prior studies have suggested that the characteristic behaviors associated with escalation of drug use are caused, at least in part, by ethanol-evoked changes in gene expression affecting synaptic plasticity. Implicit in this hypothesis is a dependence on new protein synthesis and remodeling at the synapse. It is well established that mRNA can be transported to neuronal distal processes, where it can undergo localized translation that is regulated in a spatially restricted manner in response to stimulation. It is unknown whether such modulation of the synaptic transcriptome might contribute to ethanol-induced synaptic plasticity. Using ethanol-induced behavioral sensitization as a model of neuroplasticity, here we investigated whether repeated exposure to ethanol altered the synaptic transcriptome, contributing to synaptic plasticity underlying a subsequent increase in the ethanol-evoked locomotor response. A synaptoneurosome preparation was utilized to enrich for RNAs trafficked to the synapse versus the proximal cellular fraction. Two complementary methods of genomic profiling, RNA-Seq and microarrays, were used to survey the synaptic transcriptome of DBA/2J mice subjected to ethanol-induced behavioral sensitization. Strikingly, a large number of genes regulated by acute ethanol showed adaptation to repeated ethanol exposure with sensitization. Genomic profiling showed distinct functional classes in RNA found to be enriched in the synaptoneurosome faction, consistent with their role in synaptic function. A subset of ethanol-responsive genes significantly enriched at the synapse were related to biological functions such as protein folding and extra-cellular matrix components, suggesting a role for local regulation of synaptic protein function by ethanol. In contrast, RNA classes regulated by ethanol in the cell soma included an over-abundance of RNA-binding and trafficking proteins, perhaps reflecting increased demand for dendritic RNA localization. These experiments document that both acute and repeated ethanol produce specific alterations in the complement of RNA at the synapse and lay the foundation for further investigations into the role of the synaptic transcriptome in behavioral adaptations to ethanol.

Project description:Repeated exposure to cocaine causes sensitized behavioral responses and increased dendritic spines on medium spiny neurons of the nucleus accumbens (NAc). We find that cocaine regulates myocyte enhancer factor 2 (MEF2) transcription factors to control these two processes in vivo. Cocaine suppresses striatal MEF2 activity in part through a novel mechanism involving cAMP, the regulator of calmodulin signaling (RCS), and calcineurin. We show that reducing MEF2 activity in the NAc in vivo is required for the cocaine-induced increases in dendritic spine density. Surprisingly, we find that increasing MEF2 activity in the NAc, which blocks the cocaine-induced increase in dendritic spine density, enhances sensitized behavioral responses to cocaine. Together, our findings implicate MEF2 as a key regulator of structural synapse plasticity and sensitized responses to cocaine, and suggest that reducing MEF2 activity (and increasing spine density) in NAc may be a compensatory mechanism to limit long-lasting maladaptive behavioral responses to cocaine. Mice were treated for 7 days with daily injections of cocaine (20 mg/kg) and sacrificed 24 hrs later. Chromatin from bilateral punches of NAc was immunoprecipitated with an antibody against MEF2A as described previously with minor modifications (Renthal et al., 2007). Chromatin was sonicated to an average of ~500 bp and immunoprepitated with antibody against MEF2A (Santa Cruz, sc-313) or an IgG control (Upstate/Millipore). Antibody-bound chromatin was precipitated using Protein A beads from Upstate (06-157), which were washed with low salt, high salt, and LiCl buffers to remove non-specific DNA binding. Eluted chromatin was reverse-crosslinked at 65oC in the presence of proteinase K and EDTA. DNA was purified by chloroform extraction/ethanol precipitation and the enrichment of specific promoters was amplified by ligation-mediated PCR for genome-wide analysis (Sikder et al., 2006). Amplified DNA was then labeled with Cy3 (input-enriched) or Cy5 (MEF2-enriched) and hybridized to Nimblegen (Madison, WI) MM8 mouse promoter arrays. Bilateral nucleus accumbens from eight mice were pooled for microarray analysis.

			Action	DRS
	SRR33483063_1.fastq.gz	Fastqsanger.gz
	SRR33483063_2.fastq.gz	Fastqsanger.gz
	SRR33483064_1.fastq.gz	Fastqsanger.gz
	SRR33483064_2.fastq.gz	Fastqsanger.gz

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Synaptic and Intrinsic Plasticity Mediated by CCK-type Signaling Coordinates Behavioral Changes During Motivational State Shifts

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