Inflammation-Induced Behavioral Alterations: A Psychogenomic Approach

描述（由申请人提供）：重度抑郁症是发达国家的第二大疾病负担，也是导致残疾的主要原因。炎症在抑郁症中的作用已经确立，但要更全面地了解与炎症诱导抑郁症相关的分子机制和生物学过程，需要对个体候选系统“盒子外”的可能性进行调查。这项应用的基本原理是通过全基因组功能分析和炎症诱导抑郁机制的网络重建来填补目前存在的空白。我们将整合我们良好验证和接受的卡介苗（BCG）诱导炎症的小鼠模型和我们的吲哚胺2,3双加氧酶敲除（IDO KO）小鼠来回答两个重要的和限制性的问题：目的1)在卡介苗诱导的抑郁症中，先天免疫细胞中有哪些基因差异表达？目的2)bcg诱导抑郁基因的生物学功能和网络是什么？目的1将通过表征使用RNA-Seq测量的先天免疫细胞的转录组谱来解决。我们已经展示了这一建议的三个关键基石。首先，卡介苗接种诱导了持续至少3周的长期抑郁样行为。其次，bcg诱导的抑郁是由IDO激活介导的，IDO KO小鼠与野生型小鼠一样会出现炎症，尽管它们没有表现出类似抑郁的行为。第三，肺和脑巨噬细胞在炎症行为反应中起着至关重要的作用。因此，将采用随机2x2因子设计，包括两种处理（bcg攻击和生理盐水对照）和两种小鼠品系（野生型和IDO KO）。在攻毒2周后，根据功率分析，每个攻毒组12只小鼠的肺巨噬细胞和脑小胶质细胞。组间的减法和差异表达对比将允许识别炎症诱导的抑郁基因，这些基因在抑郁样行为的长期模型中表达，并且：1)独立于可能有助于恢复的炎症和免疫的变化，2)独立于基线菌株差异。Aim 2将使用Aim 1中鉴定的基因的抽象功能分析和基因网络重建来解决。除了知识发现之外，我们将测试抑郁症功能特征的具体假设，包括：血清素，鸟嘌呤-四氢生物蝶呤，一氧化氮，能量代谢途径和转录因子。关键转录本将使用实时定量PCR确认。一个由神经科学、行为、免疫、转录组分析和生物信息学专家组成的多学科团队已经成立，以完成拟议的研究。由于提出了靶向RNA-Seq“探索性实验”和通路和网络的创新比较，因此申请提交给R21项目。拟进行的研究结果如下：1)确定炎症诱导抑郁的分子机制，包括免疫途径和调节基元；2)阐明炎症和抑郁之间的关系；3)了解相关过程，如年龄依赖性炎症诱导抑郁和其他炎症相关神经系统疾病，包括焦虑、自闭症、精神分裂症、阿尔茨海默病和人类免疫缺陷病毒引起的痴呆。对酒精和毒品上瘾。

DESCRIPTION (provided by applicant): Major depression is the second largest burden of disease in the developed world and a leading cause of disability. The role of inflammation in depression has been established, yet a more complete understanding of the molecular mechanisms and biological processes associated with inflammation-induced depression requires an investigation of possibilities that lie "outside the box" of individual candidate systems. The rationale of this application is to fill the void that currently exists through a genome-wide functional analysis and network reconstruction of the mechanisms of inflammation-induced depression. We will integrate our well-validated and accepted murine model of Bacillus Calmette-Guerin (BCG) induced inflammation and our indoleamine 2,3 dioxygenase knock-out (IDO KO) mice to answer two important and rate-limiting questions: Aim 1) What genes are differentially expressed in innate immune cells in BCG-induced depression? Aim 2) What are the biological functions and networks of the BCG-induced depression genes? Aim 1 will be addressed by characterizing the transcriptome profile of innate immune cells measured using RNA-Seq. We have demonstrated the three pivotal cornerstones for this proposal. First, BCG inoculation induces long-lasting depression-like behaviors that persist for at least 3 weeks. Second, BCG-induced depression is mediated by IDO activation and IDO KO mice develop inflammation just as wild-type mice, although they do not display depression-like behaviors. Third, lung and brain macrophages play a crucial role in mounting inflammatory behavioral response. Therefore, a randomized 2x2 factorial design including two treatments (BCG-challenge and saline control) and two mice strains (wild type and IDO KO) will be used. Lung macrophages and brain microglia from 12 mice per challenge-strain group, based on power analysis, will be collected 2 weeks after challenge. Subtractive and differential expression contrasts between groups will permit identification of inflammation-induced depression genes that are expressed in a long-lasting model of depression-like behavior and: 1) are independent of changes in inflammation and immunity that may contribute to recovery, and 2) are independent of baseline strain differences. Aim 2 will be addressed using abstractionist functional analyses of the genes identified in Aim 1 and gene network reconstruction. In addition to knowledge discovery, we will test concrete hypotheses on the functional signature of depression, including: serotonin, guanine-tetrahydrobiopterin nitric oxide, and energy metabolism pathways and transcription factors. Key transcripts will be confirmed using Real Time Quantitative PCR. A multidisciplinary team with expertise in neuroscience, behavior, immunity, transcriptome analysis and bioinformatics has been assembled to accomplish the proposed research. This application is submitted to the R21 program because a targeted RNA-Seq "exploratory experiment" and innovative comparison of pathways and networks are proposed. The outcomes of the proposed research are: 1) identification of molecular mechanisms including immune pathways and regulatory motifs that underlie inflammation-induced depression, 2) elucidation of the relationship between inflammation and depression, and 3) insights on related processes such as age-dependent inflammation-induced depression and other inflammation-associated neurological disorders, including anxiety, autism, schizophrenia, Alzheimer's disease and dementia caused by human immunodeficiency virus, and addictions to alcohol and drugs. PUBLIC HEALTH RELEVANCE: We already know from converging clinical and experimental data that depression develops on a background of sickness under conditions of inflammation. A comprehensive understanding of the molecular basis of inflammation-induced depression will result from this first systems biology approach to investigate the transcriptome profile using functional analysis followed by gene network reconstruction. The outcomes of this study in terms of knowledge discovery and hypothesis generation will help to develop prognostic and diagnostic tools that will lead to preventive and remedial treatments for those afflicted by inflammation-induced behavioral disorders.