Longitudinal genome-wide transcriptome study of PTSD symptom change in WTC responders

摘要 9/11世贸中心恐怖袭击是一场巨大的灾难，造成了长期的人身伤亡 以及对应答者的心理创伤，特别是创伤后应激障碍和下呼吸道症状， 10-20%的应答者在十年后出现的症状与创伤后应激障碍的诊断一致。我们的 研究小组发现，WTC应答者的创伤后应激障碍与他们的呼吸系统疾病密切相关，并且创伤后应激障碍介导 WTC暴露与LRS的关系。遗传易损性与基因-环境相互作用 与创伤后应激障碍的病因有关。在我们对发现N=195个WTC的队列的初步研究中 应答者，我们发现有和没有应答者之间的基因表达有显著差异 目前的WTC-PTSD诊断，使用全基因组转录组分析。相关基因在人体内的表达 缓解的创伤后应激障碍病例是当前病例和非病例之间的中介。重要的是，之前 相关基因(FKBP5、NR3C1)与几种白介素IL(IL4、IL2)差异表达， 与炎症性疾病相关的胰岛素受体、B细胞、淋巴细胞和PTEN信号通路 还有癌症。我们在N=87的独立复制样本中测试了得到的表达复合体 应答者，并实现了0.734的AUC。该复合材料还显示出与自身的 创伤后应激障碍症状严重性的报告测量，创伤后应激障碍检查表(PCL)(Spearman R=0.422)。这些初步发现支持了基因表达研究的潜在重要性 创伤后应激障碍的生物标志物。拟议的研究建立在这项令人兴奋的试点工作的基础上，通过评估 在18个月的时间里，随着创伤后应激障碍症状严重程度和LRS的变化，基因表达的变化。 使用我们储存的血液样本，我们将进行最先进的高通量RNA测序(RNA-Seq) 从全血中生成转录组图谱，每个样本的平均测序深度为50M读数 每个时间点(针对两个时间点中的每个时间点)。在本研究的目标1中，我们将调查两者之间的关联 基因表达的变化(基因、异构体和剪接变异水平)与创伤后应激障碍的变化 在基因的18个月期间的症状以及这些变化所涉及的遗传途径；以及 确定与创伤后应激障碍症状变化相关的基因表达特征(GES)。在目标2中，我们将 评估GES是否与每个创伤后应激障碍症状维度的变化相关(重新体验， 回避、麻木、极度觉醒)。我们希望找到共同的和不同的基因/途径来调节 创伤后应激障碍各症状维度的变化。在目标3中，我们将测试预期的方向性 GES评分与创伤后应激障碍症状严重程度的关系，即GES是否在第一时间点 预测18个月后创伤后应激障碍的严重程度，反之亦然。在目标4中，我们将评估GES的变化 与LRS的变化有关。我们假设GES和LRS之间观察到的任何联系 将通过创伤后应激障碍症状严重性的变化来调节，这表明共同的生物学机制支撑着 创伤后应激障碍-LRS共病。这将是第一个确定该基因及其异构体表达的纵向研究。 与总体创伤后应激障碍症状的变化以及四种创伤后应激障碍症状的变化相关联的签名 维度和共病LRS。对支持创伤后应激障碍的生物过程有深入的了解， 通过识别维持创伤后应激障碍的过程和 作为干预的目标，并将为WTC响应者和其他人员的治疗发展提供信息 受创伤影响的人群。

ABSTRACT The 9/11 World Trade Center terrorist attack was a massive disaster, resulting in long-term physical and psychological trauma to the responders, in particular PTSD and lower respiratory symptoms (LRS), with 10-20% of responders experiencing symptoms consistent with the diagnosis of PTSD a decade later. Our group found that PTSD in WTC responders is closely linked to their respiratory diseases, and PTSD mediated the relationship between WTC exposures and LRS. Genetic vulnerability and gene-environment interactions have been implicated in the etiology of PTSD. In our pilot study of a discovery cohort of N=195 WTC responders, we found significant differences in gene expression between responders with versus without a current WTC-PTSD diagnosis, using whole genome transcriptome analysis. Expression of relevant genes in remitted PTSD cases was intermediary between current cases and non-cases. Importantly, previously implicated genes (FKBP5, NR3C1) were differentially expressed along with several interleukin (IL4, IL2), insulin receptor, B-cell, lymphocytes and PTEN signaling pathways that are linked to inflammatory diseases and to cancers. We tested the resulting expression composite in an independent replication sample of N=87 responders and achieved an AUC of .734. The composite also showed a robust linear association with a self- reported measure of PTSD symptom severity, the Posttraumatic Stress Disorder Checklist (PCL) (Spearman r=0.422). These preliminary findings support the potential importance of gene expression research to identify biomarkers of PTSD. The proposed study builds on this exciting pilot work by evaluating association between changes in gene expression with changes in PTSD symptom severity and LRS across an 18-month period. Using our banked blood samples, we will conduct state-of-the-art high-throughput RNA-sequencing (RNA-Seq) to generate transcriptome profiles from whole blood at an average sequencing depth of 50M reads per sample per time point (for each of the two time points). In Aim 1 of this study, we will investigate the association between changes in gene expression (gene, isoform and splice variant levels) and changes in PTSD symptoms across an 18-month period at gene as well the genetic pathways implicated by these changes; and identify the Gene Expression Signature (GES) associated with change in PTSD symptoms. In Aim 2, we will evaluate whether the GES is associated with change in each PTSD symptom dimension (re-experiencing, avoidance, numbing, hyperarousal). We expect to find both common and distinct genes/pathways regulating the change in each PTSD symptom dimension. In Aim 3, we will test the directionality of prospective associations between the GES score and PTSD symptom severity, i.e., whether the GES at the first time point predicts PTSD severity 18 months later, and vice versa. In Aim 4, we will evaluate whether the change in GES is associated with change in LRS. We hypothesize that any association observed between the GES and LRS will be mediated by change in PTSD symptom severity, indicating shared biological mechanisms underpinning PTSD-LRS comorbidity. This will be the first longitudinal study to identify the gene and isoform expression signatures associated with change in PTSD symptoms overall, as well as each of four PTSD symptom dimensions and comorbid LRS. An in-depth understanding of the biological processes underpinning PTSD, and identification of its GES carries clinical significance by identifying processes that maintain PTSD and can be targeted for intervention, and will inform treatment development for WTC responders as well as other trauma-exposed populations.