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，也是残疾的主要原因。炎症在抑郁症中的作用已经确定，但更完整的了解与炎症诱导的抑郁症相关的分子机制和生物学过程需要调查的可能性，躺在“盒子外”的个别候选系统。该应用的基本原理是通过炎症诱导的抑郁症机制的全基因组功能分析和网络重建来填补目前存在的空白。我们将整合我们经过充分验证和接受的卡介苗（BCG）诱导的炎症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和限速的问题：目的1）BCG诱导的抑郁症中先天免疫细胞中差异表达的基因是什么？目的2）BCG诱导的抑郁症相关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，卡介苗接种诱导持续至少3周的持久抑郁样行为。其次，BCG诱导的抑郁症是由IDO激活介导的，IDO KO小鼠与野生型小鼠一样发生炎症，尽管它们不显示抑郁样行为。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，将使用随机化2x2析因设计，包括两种处理（BCG激发和盐水对照）和两种小鼠品系（野生型和IDO KO）。基于功效分析，将在攻毒后2周收集每个攻毒品系组12只小鼠的肺巨噬细胞和脑小胶质细胞。组之间的消减和差异表达对比将允许鉴定在抑郁样行为的持久模型中表达的炎症诱导的抑郁基因，并且：1）独立于可能有助于恢复的炎症和免疫的变化，和2）独立于基线应变差异。目标2将使用抽象功能分析的目标1和基因网络重建中确定的基因。除了知识发现，我们将测试抑郁症的功能签名的具体假设，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。将使用真实的时间定量PCR确认关键转录本。一个具有神经科学，行为，免疫，转录组分析和生物信息学专业知识的多学科团队已经组装完成了拟议的研究。该申请提交给R21计划，因为提出了一个有针对性的RNA-Seq“探索性实验”和创新的途径和网络比较。拟议研究的成果如下：1）鉴定分子机制，包括炎症诱导的抑郁症的免疫途径和调节基序，2）阐明炎症和抑郁症之间的关系，和3）对相关过程的见解，例如年龄依赖性炎症诱导的抑郁症和其他炎症相关的神经障碍，包括焦虑症、自闭症、精神分裂症，由人类免疫缺陷病毒引起的阿尔茨海默病和痴呆症，以及酒精和药物成瘾。 公共卫生相关性：我们已经从临床和实验数据中了解到，抑郁症是在炎症条件下的疾病背景下发展起来的。炎症诱导的抑郁症的分子基础的全面理解将导致从这第一个系统生物学方法，研究转录组配置文件使用功能分析，然后基因网络重建。本研究在知识发现和假设生成方面的结果将有助于开发预后和诊断工具，从而为炎症诱导的行为障碍患者提供预防和补救治疗。

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.