Prenatal Cannabis Exposure and Epigenetic Mechanisms Underlying Vulnerability to

产前大麻暴露和脆弱性背后的表观遗传机制

• 批准号: 8530204
• 负责人: Claudia Vargas Morris
• 金额: $ 2.84万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-07-16
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8530204
• 关键词: Address; Adult; Affect; Animals; Attention; Behavior; Behavioral; Biological; Brain; Brain region; CNR1 gene; Cannabis; Cannabis sativa plant; Cell Culture Techniques; Cell Line; Chromatin; Chromatin Structure; Clinical Research; Collection; Communities; Corpus striatum structure; Data; Development; Disease; Dopamine; Dopamine D2 Receptor; Dopamine Receptor; Drug Addiction; Drug Exposure; Environment; Enzymes; Epidemiologic Studies; Epigenetic Process; Event; Experimental Designs; Exposure to; Fetus; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Genotype; Growth; Heroin; Histocytochemistry; Histone H3; Histones; Human; Illicit Drugs; In Situ Hybridization; Individual; Investigation; Laboratories; Life; Link; Long-Term Effects; Lysine; Maintenance; Marijuana; Marijuana Smoking; Mental Depression; Mental disorders; Messenger RNA; Methylation; Methyltransferase; Modeling; Modification; Molecular; Mothers; Neurobiology; Neurons; Neurotransmitters; North America; Nucleus Accumbens; Pattern; Pharmaceutical Preparations; Phenotype; Predisposition; Pregnancy; Pregnant Women; Process; Proteins; RNA Polymerase II; Rattus; Receptor Gene; Regulation; Reporting; Research; Reverse Transcriptase Polymerase Chain Reaction; Risk; Schizoaffective Disorders; Schizophrenia; Self Administration; System; Techniques; Transcript; Western Blotting; addiction; cannabinoid receptor; design; drug development; epigenome; fetal; histone modification; human fetus tissue; in utero; in vivo; insight; interest; knock-down; lentiviral-mediated; mRNA Expression; neurodevelopment; neuropsychiatry; neurotransmission; overexpression; pregnant; prenatal; receptor; receptor expression; receptor function; research study; statistics; transmission process

DESCRIPTION (provided by applicant): An increasing number of states are legalizing marijuana (Cannabis sativa), yet the neurobiological consequences are largely unknown. During pregnancy, the human fetus is particularly vulnerable to exogenous insults, such as exposure to drugs. To date, cannabis is the most commonly abused illicit drug by pregnant mothers in North America. Epidemiological studies have documented a significant link between repeated early cannabis exposure and an increased risk for subsequent neuropsychiatric abnormalities, including drug addiction and schizoafective disorders. Cannabis is known to target cannabinoid receptors, which are involved in hardwiring the brain during the prenatal period and are expressed on neurons that control dopamine neurotransmission in the nucleus accumbens (NAc). Data from both our unique human fetal brain collection and rat model show a significant decrease in dopaminergic D2 receptor (Drd2) gene expression in the NAc folowing prenatal cannabis/THC exposure. Interestingly, our animal studies demonstrated that this D2 receptor reduction is caused by altered mRNA expression and it persists into adulthood, thus indicating a molecular mechanism, which can sustain a long- term temporal effect that canot be explained by individual genotype. The epigenome controls gene regulation and is influenced by the environment, thus it is a highly relevant biological candidate capable of maintaining aberrant D2 receptor function as a result of developmental drug exposure. A major epigenetic mechanism known to be crucial for neurodevelopment is covalent modifications of nucleosomal histones on chromatin that regulate gene transcription. Preliminary data indicate that the Drd2 gene contains abnormal histone H3 methylation marks in adult rats that were exposed to THC prenatally. The purpose of this proposal is to evaluate how prenatal THC exposure alters chromatin methylation through histone modifying enzymes that disrupt the regulation and function of D2 receptors, leading to increased sensitivity to develop addiction later in life. To investigate the mechanisms underlying histone modification disruption, mRNA and protein levels of histone modifying enzymes will be determined by qPCR and western blot analysis in rats exposed to THC prenatally. The striatal anatomical pattern of the identified histone modifying enzyme mRNA levels will be examined in cannabis and control subjects from our unique human fetal brain bank. To determine the specific histone modifying enzymes behind Drd2 reduction, candidate proteins wil be manipulated via knock-down or overexpression in a neuronal cell line and consequences on the chromatin structure and Drd2 expression will be studied. Lentiviral-mediated modulation of the expression of the relevant histone modifer identified will be conducted in the NAc of rats with prenatal THC exposure and the behavioral consequences evaluated in relation to heroin self- administration to gain insight into the relationship between THC-induced molecular changes and phenotype.

描述（由申请人提供）：越来越多的州将大麻合法化，但其神经生物学后果在很大程度上尚不清楚。在怀孕期间，人类胎儿特别容易受到外源性损伤，例如暴露于药物。迄今为止，大麻是北美孕妇最常滥用的非法药物。流行病学研究证明，早期反复接触大麻与随后出现神经精神异常（包括吸毒成瘾和精神官能症）的风险增加之间存在着重要联系。已知大麻以大麻素受体为靶点，大麻素受体参与产前期间大脑的硬连线，并在控制多巴胺神经传递的神经元上表达。我们独特的人类胎儿大脑收集和大鼠模型的数据显示，在产前大麻/THC暴露后，NAc中多巴胺能D2受体（Drd 2）基因表达显著降低。有趣的是，我们的动物研究表明，这种D2受体减少是由mRNA表达改变引起的，并且它持续到成年期，因此表明了一种分子机制，该机制可以维持一种无法用个体基因型解释的长期暂时效应。表观基因组控制基因调控并受环境影响，因此它是一种高度相关的生物学候选物，能够在发育药物暴露后维持异常的D2受体功能。已知对神经发育至关重要的主要表观遗传机制是调节基因转录的染色质上的核小体组蛋白的共价修饰。初步数据表明，在产前暴露于THC的成年大鼠中，Drd 2基因含有异常的组蛋白H3甲基化标记。这项提案的目的是评估产前THC暴露如何通过组蛋白修饰酶改变染色质甲基化，破坏D2受体的调节和功能，导致在以后的生活中成瘾的敏感性增加。为了研究组蛋白修饰破坏的潜在机制，将通过qPCR和蛋白质印迹分析来确定产前暴露于THC的大鼠中组蛋白修饰酶的mRNA和蛋白质水平。将在我们独特的人类胎儿脑库的大麻和对照受试者中检查所鉴定的组蛋白修饰酶mRNA水平的纹状体解剖模式。为了确定Drd 2减少背后的特定组蛋白修饰酶，将通过在神经元细胞系中敲低或过表达来操纵候选蛋白，并将研究对染色质结构和Drd 2表达的影响。将在具有产前THC暴露的大鼠的NAc中进行慢病毒介导的对鉴定的相关组蛋白修饰剂的表达的调节，并评价与海洛因自我施用相关的行为后果，以深入了解THC诱导的分子变化与表型之间的关系。