The impact of stress-induced DNA breaks on chromatin structure, gene activity, and neuron function

应激诱导的 DNA 断裂对染色质结构、基因活性和神经元功能的影响

基本信息

批准号：
10655982
负责人：
Ram Madabhushi
金额：
$ 79.98万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-05 至 2028-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10655982
关键词：
Affect Agonist Architecture Area Atrophic Automobile Driving Behavior Behavioral Behavioral Symptoms Brain Brain region Brain-Derived Neurotrophic Factor Breeding Candidate Disease Gene ChIP-seq Chromatin Chromatin Conformation Capture and Sequencing Chromatin Loop Chromatin Structure Chronic Chronic stress Clinical Research Cognition Cognitive Cognitive deficits Complex Confocal Microscopy DLG4 gene DNA DNA Double Strand Break Diazepam ERG gene Early Promoters Enhancers Enzymes Epigenetic Process Etoposide Exposure to FOSB gene FRAP1 gene Gene Expression Genes Genetic Transcription Genome Mappings Genotype Heterochromatin Hippocampus Hour Infusion procedures Knowledge Label Length Major Depressive Disorder Maps Mediating Mental disorders Molecular Mus NPAS4 gene Neurobehavioral Manifestations Neurobiology Neurons Pathway interactions Pattern Poison Post-Traumatic Stress Disorders Prefrontal Cortex Prosencephalon Proteins Recurrence Reporting Rodent Role Site Sorting Stress Stressful Event Structure Synapses Synaptic plasticity Synaptosomes Testing Topoisomerase Work candidate identification chromatin remodeling chromosome conformation capture cohort density experience experimental study genome-wide genomic locus gephyrin inhibitor insight lateral ventricle nervous system disorder novel novel therapeutic intervention osmotic minipump preclinical study promoter receptor transcriptome sequencing

项目摘要

PROJECT SUMMARY: Chronic stress causes molecular adaptations and structural remodeling of neurons within corticolimbic brain areas, including the prefrontal cortex (PFC) and hippocampus (HPC). This is important because the PFC and HPC are integrated in brain circuits that regulate complex behaviors and cognition. Preclinical and clinical studies indicate that synapse loss and reduced connectivity in the PFC and HPC contribute to behavioral and cognitive symptoms in several psychiatric disorders, such as post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). While previous reports have identified candidate genes and pathways, the molecular mechanisms that cause lasting stress-induced changes in gene activity patterns and structural remodeling in neurons remain unknown. In preliminary studies, exposing mice to chronic unpredictable stress (CUS) triggered the formation of DNA double strand breaks (DSBs) within stress-activated neurons in the PFC. Administration of the GABAA receptor agonist, diazepam, diminished both the number of stress-activated neurons and the levels of DSBs, suggesting that stress-induced DSBs are generated by activity-dependent mechanisms. Accumulating evidence indicates that neuronal activity induces the topoisomerase, topoisomerase II (Top2B) to generate DSBs and promote the transcription of an important subset of genes that mediate experience-driven synaptic changes, including early response genes (ERGs), such as Fos, Npas4, Egr1, and Arc. These results suggest that experience-dependent DSB formation could regulate stress-induced gene activity patterns and subsequent remodeling of neurons. Yet the sites of stress-induced DSBs in PFC and HPC neurons have not been mapped and how DSBs affect stress-related gene activity patterns has not been explored. Interestingly, preliminary studies revealed that recurrent and ectopic induction of Top2B-mediated DSBs in cultured neurons is sufficient to recapitulate chronic stress-induced gene expression profiles for various neuronal activity-responsive genes, including ERGs and Bdnf. Preliminary chromosome conformation capture (3C)-based experiments (3C and 4C-seq) further suggest that DSBs regulate gene activity patterns by altering chromatin topology. These observations have led to the hypothesis that recurrent DSB formation during chronic stress alters chromatin architecture at associated genes, which in turn, stabilizes stress-related gene activity patterns that trigger neuronal remodeling and synapse loss in the PFC and HPC. To test this hypothesis, the proposed studies will map genome-wide sites of CUS-induced DSBs and utilize conditional deletion of Top2b to define how DSBs affect stress-dependent changes in transcription and neuronal structure and function in PFC and HPC projection neurons. Additionally, 3C-based methods (HiChIP) will be employed to assess how DSBs affect stress-dependent changes to chromatin architecture. Together, these efforts will provide novel insights into the mechanisms driving stress-induced neuronal adaptations, and may uncover new therapeutic strategies for psychiatric disorders, such as PTSD and MDD.

项目摘要：慢性应激会导致皮质唇内神经元的分子适应和结构重塑大脑区域，包括前额叶皮层（PFC）和海马（HPC）。这很重要，因为PFC HPC和HPC集成在调节复杂行为和认知的大脑回路中。临床前和临床研究表明，PFC和HPC中突触丧失和降低的连通性有助于行为和几种精神疾病的认知症状，例如创伤后应激障碍（PTSD）和主要抑郁症（MDD）。虽然先前的报告已经鉴定了候选基因和途径，但分子引起持久压力引起的基因活性模式变化和结构重塑的机制神经元仍然未知。在初步研究中，将小鼠暴露于触发的慢性不可预测的压力（CUS） PFC中应力激活神经元内的DNA双链断裂（DSB）的形成。管理 GABAA受体激动剂（地西epam）减少了压力激活的神经元的数量和水平 DSB的大量，表明应力诱导的DSB是由活动依赖性机制产生的。累积证据表明，神经元活性诱导拓扑异构酶，拓扑异构酶II（TOP2B）产生 DSB并促进了介导经验驱动突触的重要基因的重要子集的转录变化，包括早期反应基因（ERG），例如FOS，NPAS4，EGR1和ARC。这些结果表明依赖经验的DSB形成可以调节应激诱导的基因活性模式，然后调节神经元的重塑。然而，尚未映射PFC和HPC神经元中应力诱导的DSB的位点 DSB如何影响与压力相关的基因活性模式尚未探索。有趣的是，初步研究表明，TOP2B介导的DSB的复发和生态诱导在培养的中，神经元足以概括各种慢性应激诱导的基因表达谱神经活性响应基因，包括ERG和BDNF。初步染色体会议捕获（基于3C）的实验（3C和4C-Seq）进一步表明，DSB通过改变基因活性模式染色质拓扑。这些观察结果导致了一个假设，即慢性期间复发的DSB形成应力改变相关基因的染色质结构，从而稳定与应力相关的基因活性 PFC和HPC中触发神经元重塑和突触损失的模式。为了检验这一假设，拟议的研究将绘制CUS诱导的DSB的全基因组位点，并利用TOP2B的条件缺失为定义DSB如何影响压力依赖性转录和神经元结构的变化以及PFC中的功能和HPC投影神经元。此外，将执行基于3C的方法（HICHIP）以评估DSB 影响压力依赖性的变化对染色质结构。这些努力将共同提供新颖的见解进入推动压力引起的神经元适应的机制，并可能发现新的治疗策略用于PTSD和MDD等精神疾病。