Genetic and estrogen-dependent regulation of the human PAC1R receptor and PTSD

描述（由申请人提供）：创伤后应激障碍（PTSD）是一种适应不良和使人衰弱的精神障碍，其特征在于创伤发生时的极端恐惧感，在创伤后数月和数年内具有特征性的重新体验、回避和过度觉醒症状。PTSD的患病率约为6%，但可能发生在经历过严重心理创伤的受试者中高达25%，如退伍军人，难民和袭击受害者。决定那些与那些没有发展PTSD的人相比的差异风险是多因素决定的：1）它部分是遗传的，创伤后PTSD的风险遗传率约为30-40%; 2）它与性别有关，女性在创伤后发展PTSD的风险约为男性的两倍; 3）它部分取决于过去的个人历史，包括成人和儿童创伤以及可能差异介导恐惧和情绪调节的心理因素。磷腺苷酸环化酶激活多肽（PACAP）以前已被确定为跨物种的应激反应的关键调节因子。我们最近发现，PACAP及其PAC 1受体（PAC 1 R）可能是心理创伤后异常过程的关键介质，例如人类创伤后应激障碍（PTSD）。我们最近发现，在严重创伤的人类受试者中，PACAP血液水平与女性的恐惧生理学、PTSD诊断和症状存在性别特异性关联（N=64，重复N=74，p<0.005）。使用跨越PACAP（ADCYAP 1）和PAC 1 R（ADCYAP 1 R1）基因的tag-SNP遗传方法（44个单核苷酸多态性，SNP），我们发现单个SNP（rs 2267735）与恐惧和PTSD症状之间存在性别特异性关联。存在于PAC 1 R内推定的雌激素反应元件（ERE）中的SNP预测女性的恐惧反应、PTSD诊断和症状（合并的初始和重复样品：N=1237; p<2x 10 -5）。该SNP的存在与PAC 1 R mRNA表达呈负相关，PAC 1 R甲基化与PTSD相关（p < 0.001）。补充这些人类数据，我们发现PAC 1 R mRNA在啮齿动物模型中被恐惧条件反射或雌激素替代诱导。这些数据表明，PACAP/PAC 1 R通路的扰动参与了PTSD潜在的异常恐惧反应。该提案旨在通过更大的样本量来扩展这些初步发现，将PACAP/PAC 1通路活性的外周标志物确定为PTSD的生物标志物。我们将进一步扩展这些数据，通过检查雌激素的作用，PAC 1 R DNA甲基化/组蛋白乙酰化，和PAC 1 R mRNA表达PTSD症状和恐惧生理创伤的女性受试者。我们将使用不同PAC 1 rs 2267735基因型的人淋巴母细胞系进一步研究PAC 1调节的机制。

DESCRIPTION (provided by applicant): Post-traumatic stress disorder (PTSD) is a maladaptive and debilitating psychiatric disorder characterized by an extreme sense of fear at the time of trauma occurrence, with characteristic re- experiencing, avoidance, and hyperarousal symptoms in the months and years following the trauma. PTSD has a prevalence of approximately 6%, but can occur in up to 25% of subjects who have experienced severe psychological trauma, such as combat veterans, refugees, and assault victims. The differential risk determining those who do vs. those who do not develop PTSD is multi-determined: 1) it is in part genetic, with approximately a 30-40% risk heritability for PTSD following trauma; 2) it in par depends on sex, with women having approximately twice the risk as men to develop PTSD following trauma; and 3) it in part depends on past personal history, including adult and childhood trauma and psychological factors which may differentially mediate fear and emotion regulation. Pituitary adenylate cyclase-activating polypeptide (PACAP) has previously been identified as a critical regulator of the stress response across species. We have recently shown that PACAP and its PAC1 receptor (PAC1R) may be critical mediators of abnormal processes following psychological trauma, such as with posttraumatic stress disorder (PTSD) in humans. We recently found, in heavily traumatized human subjects, a sex-specific association of PACAP blood levels with fear physiology, PTSD diagnosis and symptoms in females (N=64, replication N=74, p<0.005). Using a tag-SNP genetic approach (44 single nucleotide polymorphisms, SNPs) spanning the PACAP (ADCYAP1) and PAC1R (ADCYAP1R1) genes, we found a sex-specific association between a single SNP (rs2267735) and fear and PTSD symptoms. The SNP residing in a putative estrogen response element (ERE) within PAC1R, predicts fear response, PTSD diagnosis and symptoms in females (combined initial and replication samples: N=1237; p<2x10-5). The presence of this SNP is inversely correlated with PAC1R mRNA expression, and methylation of PAC1R is associated with PTSD (p < 0.001). Complementing these human data, we found that PAC1R mRNA is induced with fear conditioning or estrogen replacement in rodent models. These data suggest that perturbations in the PACAP/PAC1R pathway are involved in abnormal fear responses underlying PTSD. This proposal aims to extend these initial findings with a larger sample size, identifying peripheral markers of PACAP/PAC1 pathway activity as a biomarker for PTSD. We will further extend these data by examining the role of estrogen, PAC1R DNA methylation / histone acetylation, and PAC1R mRNA expression on PTSD symptoms and fear physiology in traumatized female subjects. We will further examine the mechanisms of PAC1 regulation using human lymphoblast cell lines of differing PAC1 rs2267735 genotypes.