Neuronal PARP activity in fetal alcohol spectrum disorders

胎儿酒精谱系障碍中的神经元 PARP 活性

基本信息

批准号：
9917673
负责人：
SUBHASH C. PANDEY
金额：
$ 35.45万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-20 至 2022-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9917673
关键词：
Adolescence Affect Binding Birth Blood - brain barrier anatomy Brain region Brain-Derived Neurotrophic Factor Cell Differentiation process Cell Nucleus Cell Survival Cell physiology Chromatin Clinical Clinical Trials DNA Binding DNA Methylation Data Dendrites Development Developmental Gene Disease Disease model Dose Drug Targeting Enzymes Epigenetic Process Ethanol Executive Dysfunction FDA approved Fetal Alcohol Exposure Fetal Alcohol Spectrum Disorder Future Gene Expression Gene Expression Regulation Gene Silencing Genes Genetic Transcription Growth Heavy Drinking Histone H3 Human Impaired cognition Impairment In Vitro Incubated Intellectual functioning disability Life Lysine Measures Medial Mediating Memory impairment Mitotic Molecular Neonatal Neonatal Alcohol Exposure Neurons PPAR gamma Pathway interactions Pharmacology Poly Adenosine Diphosphate Ribose Poly(ADP-ribose) Polymerases Post-Translational Protein Processing Prefrontal Cortex Pregnancy Proteins Proto-Oncogene Proteins c-myc Rattus Regulator Genes Role Short-Term Memory Third Pregnancy Trimester Vertebral column alcohol effect alcohol exposure c-myc Genes density executive function fetal gene repression histone demethylase in vivo inhibitor/antagonist innovation mRNA Expression neuropsychiatry overexpression poly ADP-ribose glycohydrolase postnatal prevent promoter pup transcription factor

项目摘要

Fetal alcohol spectrum disorders (FASD) are the leading known and preventable causes of intellectual disability. They impair executive functions including working memory, a function highly dependent on the medial prefrontal cortex (mPFC). This brain region is one of the last to mature, the third trimester in humans and the first 10 days after birth in rats. This is a vulnerable period for mPFC dendrites where their growth is prone to disruption from environmental insults, such as ethanol (EtOH). Poly ADP ribose polymerases (PARP) proteins are implicated in several cellular functions, including regulating gene expression. PARP synthesizes and attaches poly (ADP-ribose) (PAR) chains (PARylating) to its targets. PARP enzymes can affect gene expression by PARylating the epigenetic enzyme KDM4D. This reduces KDM4D’s ability to remove the transcriptionally repressive, dimethylated lysine 9 at histone H3 (H3K9me2). PARP-mediated gene silencing can also be accomplished by PARylating the transcription factor Peroxisome proliferator-activated receptor gamma (PPARγ). Our underlying hypothesis is that EtOH induces PARP1 activity, promoting the addition of PAR groups to known PARP1 targets such as PPARγ and KDM4D. This post-translational modification would then reduce PPARγ and KDM4D’s ability to bind DNA or chromatin resulting in changes to neurodevelopmental gene expression, dendritic arborization, and working memory. This hypothesis is supported by our preliminary data in which EtOH increased PARP activity and reduced Bdnf IV, IXa, and Klf4 mRNA expression in primary cortical neuron cultures. These changes were reversible with a PARP inhibitor. As a direct connection between PARP and PPARγ we found that PARP inhibition increased PPARγ binding to Bdnf IV and Klf4 promoters in vitro. In vivo, neonatal EtOH treatment induced PARP activity, and this coincided with a decrease in PPARγ DNA binding ability and reduced Bdnf IV mRNA expression. Thirty-one days after the final dose, the reduction in Bdnf IV expression persisted in EtOH exposed rats. In the first aim, we plan to dissect the molecular mechanisms connecting PARP to changes in developmental gene expression in the mPFC with a focus on neuron-specific changes. In order to establish the role of PARP in EtOH induced Bdnf and Klf4 gene expression silencing we will attempt to prevent expression changes by administering a PARP inhibitor ABT-888 to EtOH treated rats. We will also dissect whether PARP mediated transcriptional repression occurs via post-translational modifications to PPARγ and KDM4D using neuron cultures. In the second aim, we will establish the role of PARP in the much-replicated deficits in mPFC dendritic arborization and neuritogenesis observed in FASD models. In the third aim, we will study the role of PARP in third trimester equivalent EtOH exposure-induced spatial working memory deficits. PARP inhibitors are known to be neuroprotective, are currently undergoing clinical trials for other disorders, and cross the blood-brain barrier. Therefore, the results of these studies may be a promising avenue for future pharmacological development.

胎儿酒精谱系障碍 (FASD) 是智力障碍的主要已知且可预防的原因。它们会损害执行功能，包括工作记忆，这是一种高度依赖于记忆的功能。内侧前额叶皮层 (mPFC) 是人类最后成熟的大脑区域之一。大鼠出生后的前 10 天，这是 mPFC 树突生长的脆弱时期。容易受到环境污染的破坏，例如乙醇 (EtOH)。蛋白质涉及多种细胞功能，包括调节 PARP 合成。并将聚（ADP-核糖）（PAR）链（PARylating）附着到其靶标上可以影响基因。通过对表观遗传酶 KDM4D 进行 PARy 表达，这会降低 KDM4D 去除的能力。组蛋白 H3 处的转录抑制性二甲基化赖氨酸 9 (H3K9me2) 介导的基因沉默。也可以通过对过氧化物酶体增殖物激活的转录因子进行 PAR 化来实现我们的基本假设是 EtOH 会诱导 PARP1 活性，从而促进将 PAR 基团添加到已知的 PARP1 靶标（例如 PPARγ 和 KDM4D）中。修饰会降低 PPARγ 和 KDM4D 结合 DNA 或染色质的能力，从而导致以下变化：神经发育基因表达、树突分枝和工作记忆。我们的初步数据支持 EtOH 增加了 PARP 活性并减少了 Bdnf IV、IXa 和 Klf4 PARP 抑制剂可逆转原代皮质神经元培养物中的 mRNA 表达。作为 PARP 和 PPARγ 之间的直接联系，我们发现 PARP 抑制增加了 PPARγ 与 Bdnf IV 和 Klf4 启动子在体内，新生儿 EtOH 处理诱导 PARP 活性，这与此一致。三十一天后，PPARγ DNA 结合能力下降，Bdnf IV mRNA 表达减少。在最终剂量中，EtOH 暴露的大鼠中 Bdnf IV 表达持续减少。剖析 PARP 与发育基因表达变化之间的分子机制 mPFC 重点关注神经元特异性变化，以确定 PARP 在 EtOH 诱导的 Bdnf 中的作用。和 Klf4 基因表达沉默，我们将尝试通过施用 PARP 来防止表达变化我们还将剖析 PARP 是否介导转录抑制。在第二个目标中，我们通过使用神经元培养物对 PPARγ 和 KDM4D 进行翻译后修饰来实现。将确定 PARP 在 mPFC 树突状树状化中重复出现的缺陷中的作用在 FASD 模型中观察到的神经发生在第三个目标中，我们将研究 PARP 在妊娠晚期的作用。已知 EtOH 暴露引起的空间工作记忆缺陷是等效的。具有神经保护作用，目前正在进行针对其他疾病的临床试验，并且可以跨越血脑屏障。因此，这些研究的结果可能是未来药理学发展的有希望的途径。