Unknown,Transcriptomics,Genomics,Proteomics

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Genome-wide analysis of acetylated H4K5 binding offers new insights into the acute and chronic effects of METH on gene expression in the dorsal striatum

ABSTRACT: In contrast to the acute METH-induced transcriptional changes, chronic METH administration produces differential changes in IEG responses and blunts the striatal effects of a single METH injection (McCoy et al., 2011). These observations suggested that chromic METH might have caused changes in the molecular machinery that controls the acute effects of the drug. Gene transcription is regulated by complex interactions of transcription factors with regulatory elements [14,15]. During resting states, DNA is compacted in a way that interferes with the binding of transcription factors whereas DNA becomes more accessible during activation of cells by various stimuli [16]. DNA is indeed packaged into chromatin whose fundamental subunit, the nucleosome, is made of 4 core histones, histones H2A, H2B, H3, and H4 that form an octomer (2 of each histone) surrounded by 146 bp of DNA [17]. The N-tails of histones possess lysine residues that can be reversibly acetylated or deacetylated by several histone acetyltransferases (HATs) or by histone deacetylases (HDACs), respectively [18,19]. These changes promote alterations in gene expression by modifying chromatin conformation and enabling or inhibiting recruitment of regulatory factors onto DNA sequences [20]. Herein, we report that the acute, but not the chronic, transcriptional effects of METH are mediated, for the most part, by increased DNA binding of histone H4 acetylated at lysine 5 (H4K5ac). These results suggest that other factors, including histone and/or DNA methylation, might play a more important role in mediating the molecular effects of chronic METH exposure. 18 samples pooled as SS (4), SM (3), MS (3), MM (4), INPUT (4): SS Saline pretreatment then saline treatment SM Saline pretreatment then METH treatment MS METH pretreatment then saline treatment MM METH pretreatment then METH treatment untreated

ORGANISM(S): Rattus norvegicus

SUBMITTER: Christie Brannock

PROVIDER: E-GEOD-42776 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Methamphetamine (METH) is a widely abused illicit amphetamine that causes acute biochemical and molecular changes in the brain. However, there are very few studies that have investigated the long-term effects of a single METH exposure in adult animals. The purpose of this study was thus to determine the consequences of a single injection of METH (10) mg/kg) on the biochemical and transcriptional effects of a second challenge injection of the drug (2.5 mg/kg) given one month later. Towards that end, we measured monoamine levels and gene expression by microarray and quantitative PCR analyses in the nucleus accumbens (NAc) of 4 groups of rats: saline-pretreated and saline-challenged (SS); saline-pretreated and METH-challenged (SM); METH-pretreated and saline-challenged (MS); and METH-pretreated and METH-challenged (MM). The rats were euthanized 2 hours after the acute challenge injection and NAc samples were harvested. The acute METH challenge caused increases in NAc DA and HVA levels in both the SM and MM groups. Microarray analyses revealed that an injection of METH (2.5 mg/kg) produced acute changes (1.8-fold; p < 0.01) in the expression of 418 (358 up-, 60 downregulated) genes including several immediate early genes (IEGs) such as Arc, c-fos, and fosB in the SM group. Several neuropeptides including Cart, Crf (Crh), and vasopressin were upregulated in that group. Injection of the higher dose of METH (10 mg/kg) did not influence monoamine levels but caused changes in 510 (345 up-, 165 downregulated) transcripts measured one month later (MS group). This list included Cart and Crf but not any IEGs. The MM group showed changes in 774 (572 up-, 202 downregulated) genes that also included vasopressin, Cart, and Crf whose expression was enhanced by the second METH injection. Quantitative PCR confirmed the METH-induced changes in the expression of the neuropeptides. We also confirmed the METH-induced potentiation of Crf expression in the METH-pretreated group. These observations suggest that a single injection of a moderate dose of METH can produce long-lasting changes in gene expression in the rodent NAc. The long-term increases in Crf expression also suggest that a single injection of a moderate METH dose can cause prolonged dysregulation in the endogenous stress system in the rat brain. 24 samples. SS (4), SM (6), MS (7), MM (7)

Project description:Methamphetamine (METH) addiction is associated with a plethora of neuropsychiatric symptoms. In rodents, administration of the drug is accompanied by complex changes in gene expression in the dorsal striatum. Very little is known about the effects of the drug on gene expression and epigenetic modifications in the nucleus accumbens (NAc). The present study was conducted in order to investigate the effects of a single injection of METH on gene expression in that structure. We also queried whether changes in transcript levels were accompanied by alterations in histone acetylation as well as in the expression of the histone acetyltransferase (HAT), ATF2, and of the histone deacetylases (HDACs), HDAC1 and HDAC2. Microarray analyses revealed that METH caused significant time-dependent increases in the expression of several genes that had previously been implicated in the acute and longterm effects of psychostimulants in the brain. These include several immediate early genes (c-fos, Egrs, c-jun, and Nurr1) and corticotropin-releasing factor (Crf). There were also increases in the levels of neuromedin U, Tnf-alpha, and Kcnk18, among others. In contrast, the METH injection caused decreases in the expression of many genes including Npas4 and cholecystokin (Cck). Pathway analyses showed that differentially affected genes participate in behavioral performance, cell-to-cell signaling and interactions, and regulation of gene expression. Other differentially affected genes are known to be involved in cellular compromise and death pathways. PCR analyses were used to confirm the changes in the expression of c-fos, fosB, c-jun, junB, Crf, NmU, Cck, and Npas4 transcripts. Western blot analyses also identified METH-mediated decreases in the acetylation of histone H3 at lysine 9 (H3K9) and lysine 18 (H3K18) as well as in histone 4 at lysine 16 (H4K16). In contrast, the METH injection caused time-dependent increases in the acetylation of H4K8 and H4K12. The changes in histone acetylation were also accompanied by decreased expression of HDAC1 but increased expression of ATF2 and of HDAC2. These results suggest that METH-induced alterations in global gene expression might be due, in part, to diverse effects of METH-induced histone acetylation secondary to changes in HAT and HDAC expression. At the indicated time after the METH or saline injections, rats (n = 5 per group) were euthanized and the NAc was dissected and immediately put on dry ice. The tissues were kept at -70 oC until RNA extraction. Total RNA was isolated from the nucleus accumbens according to the manufacturer’s manual using Qiagen RNeasy mini kit (Qiagen, Valencia, CA, USA). RNA integrity was detected using an Agilent 2100 Bioanalyzer (Agilent, Palo Alto, CA, USA).

Project description:This model is described in the article: Kinetics of histone gene expression during early development of Xenopus laevis. Koster JG, Destrée OH and Westerhoff HV. J Theor Biol. 1988 Nov 21;135(2):139-67. PMID: 3267765 Abstract: Using literature data for transcriptional and translational rate constants, gene copy numbers, DNA concentrations, and stability constants, we have calculated the expected concentrations of histones and histone mRNA during embryogenesis of Xenopus laevis. The results led us to conclude that: (i) for X. laevis the gene copy number of the histone genes is too low to ensure the synthesis of sufficient histones during very early development, inheritance from the oocyte of either histone protein or histone mRNA (but not necessarily both) is necessary; (ii) from the known storage of histones in the oocyte and the rates of histone synthesis determined by Adamson and Woodland (1977), there would be sufficient histones to structure the newly synthesized DNA up to gastrulation but not thereafter (these empirical rates of histone synthesis may be underestimates); (iii) on the other hand, the amount of H3 mRNA recently observed during early embryogenesis (Koster, 1987, Koster et al., 1988) could direct a higher and sufficient synthesis of H3 protein, also after gastrulation. We present a quantitative model that accounts both for the observed H3 mRNA concentration as a function of time during embryogenesis and for the synthesis of sufficient histones to structure the DNA throughout early embryogenesis. The model suggests that X. laevis exhibits a major (i.e. some 14-fold) reduction in transcription of histone genes approximately 11 hours after fertilization. This reduction could be due to a decrease in the number of transcribed histone genes, a decreased rate constant of transcription with continued transcription of all the histone genes, and/or a reduction in the time during the cell cycle in which histone mRNA synthesis takes place. Alternatively, the histone mRNA stability might decrease approximately 16-fold 11 hours after fertilization. This model originates from BioModels Database: A Database of Annotated Published Models. It is copyright (c) 2005-2011 The BioModels.net Team. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not.. To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.

Project description:Neuroplastic changes in the dorsal striatum participate in the transition from casual drug use to habitual and compulsive drug taking. These alterations might also play a critical role in the development of methamphetamine (METH) addiction. Nevertheless, the molecular substrates that underlie habitual METH consumption have yet to be elucidated. Therefore, in the present study, we examined the influence of METH self-administration on the expression of genes and proteins of interest, as potential substrates of METH-induced neuronal plasticity in the dorsal striatum. Rats self-administered METH (0.1 mg/kg/injection, i.v.) during 15 h sessions for 8 d and were euthanized after 2 h, 24 h, or 1 month of abstinence. Compared to yoked saline control, METH self-administration induced increases in the mRNA expression of the transcription factors, c-fos and fosb, the neurotrophic factor, Bdnf, and of the synaptic protein, synaptophysin (Syp) at 2 h after cessation of drug exposure. METH self-administration also caused changes in FosB, BDNF and TrkB protein levels, with increases at 2 and 24 h but decreases observed after 1 month of drug abstinence. Importantly, METH exposure caused increases in the levels of H3K4me3 and pCREB after 2 and 24 h of abstinence. Chromatin immunoprecipitation followed by qPCR was used to clarify the role of these proteins in the regulation of gene expression. We found that METH self-administration caused enrichment of pCREB, but not of H3K4me3, on the promoters of c-fos, fosb, Bdnf and Syp at 2 h after drug cessation. These data indicate that METH-induced activation of their transcription is mediated, in part, by pCREB-dependent epigenetic phenomena. Thus, METH self-administration might trigger epigenetic changes that caused alterations in the expression of genes and proteins serving as substrates for addiction-related synaptic plasticity. Animals were trained to self-administer METH for 8 d as described in the paper, dorsal striata were isolated 2 h, 24 h and 1 month after the final self-administration session. RNA extraction, RNA labeling and microarray hybridization were performed. In brief, total RNA was isolated from the samples using RNeasy Mini Kit (QIAGEN, Valencia, CA). RNA concentration and integrity was determined using Agilent BioAnalyzer (Agilent, Santa Clara, CA). Samples were stored at -80ÂºC. Microarray hybridization was done using RatRef-12 Expression BeadChips arrays (22 523 probes) (Illumina Inc., San Diego, CA). A 600 ng of total RNA from each sample was amplified using Illumina RNA Amplification kit (Ambion, Austin, TX). Single-stranded RNA (cRNA) was generated and labeled by incorporating biotin-16-UTP (Roche Diagnostics, Indianapolis, IN). 750 ng of each cRNA sample were hybridized to Illumina arrays at 55Â°C overnight according to the Gene Expression Protocol for BeadStation (Illumina Inc.). Hybridized cRNA was detected with cyanine3-streptavidin (GE Healthcare, Piscataway, NJ) and quantified using Illumina's BeadStation 500GX scanner.

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Genome-wide analysis of acetylated H4K5 binding offers new insights into the acute and chronic effects of METH on gene expression in the dorsal striatum

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