Sex Differences in Stress Receptors Underlie Female Vulnerability to Stress

描述（由申请人提供）：与压力相关的精神疾病，如抑郁症和创伤后应激障碍，是使人衰弱的精神疾病，影响女性的人数是男性的两倍。尽管这种差异的病因尚不清楚，但人们认为这是由于应激反应的性别差异。促肾上腺皮质激素释放因子（CRF）在一定程度上通过调节去甲肾上腺素（NE）和血清素（5-HT）的传递来协调应激反应，CRF在应激相关疾病中失调。我目前的研究目标是确定CRF （CRF1亚型）受体的性别差异，这可能解释压力反应的性别差异。迄今为止，我发现CRF1在雌性大鼠中的信号和转运方式不同，这可以解释对急性压力的反应升高和对慢性压力的适应降低。在女性中，CRF1免疫沉淀显示与介导大多数细胞反应的gtp结合蛋白Gs有更大的偶联。此外，应激诱导的CRF1与2-arrestin2（受体内化的一个重要步骤）的关联在男性中很明显，但在女性中没有。免疫电镜证实应激诱导的CRF1内化仅在雄性大鼠中发生，这表明这种补偿大量CRF的适应性过程在雌性大鼠中受损，可能在抑郁症中释放。重要的是，CRF1功能的性别差异使得雌性大鼠蓝斑区的NE神经元对低水平CRF更敏感，而对高水平CRF的适应性更差。然而，由于这是首次报道应激相关神经肽受体的性别差异，许多问题仍未得到解答。本提案的目的1，将在指导阶段（K99）完成，研究为什么CRF1在男性和女性中结合蛋白不同。CRF1结构没有性别差异，因此我将学习蛋白质组学方法来确定CRF1翻译后修饰的性别差异是否解释了这些影响。目标2和目标3将在独立阶段完成。目的2将确定导致CRF1性别差异的激素。为此，我将把之前获得的内分泌技术与K99期学到的技能结合起来，确定卵巢或睾丸激素是否建立了性别差异。目的3将评估性别差异是否延伸到中缝背核的其他受体亚型CRF2。由于CRF1和CRF2具有高度的序列同一性，蛋白质组学方法有望揭示CRF2的性别差异。CRF2激活背侧5-羟色胺系统促进应激的被动行为反应策略，这是抑郁症的一个危险因素。因此，CRF2的性别差异可能导致女性患这种疾病的易感性增加。通过解决这些问题，本建议将有助于阐明压力相关疾病中性别差异的病因学。此外，由于CRF拮抗剂正在开发用于治疗这些疾病，考虑到CRF受体的性别差异可能会增加这些化合物在女性中的功效。

DESCRIPTION (provided by applicant): Stress-related psychiatric disorders, like depression and post-traumatic stress disorder, are debilitating mental illnesses that affect twice as many women as men. Although the etiology of this disparity remains unknown, it is thought to be due to sex differences in stress responses. Corticotropin-releasing factor (CRF) orchestrates stress responses, in part, by regulating norepinephrine (NE) and serotonin (5-HT) transmission, and CRF is dysregulated in stress-related disorders. The goal of my current research is to identify sex differences in a receptor for CRF (CRF1 subtype) that may account for sex differences in stress responsivity. To date, I found that CRF1 signals and is trafficked differently in female rats in a manner that can account for elevated responses to acute stress and decreased adaptation to chronic stress. In females, CRF1 immunoprecipitation revealed a greater coupling to Gs, the GTP-binding protein that mediates most cellular responses. Additionally, stress-induced CRF1 association with 2-arrestin2, an integral step in receptor internalization, was apparent in males but not females. Immunoelectron microscopy confirmed stress-induced CRF1 internalization in male rats only, suggesting that this adaptive process to compensate for large amounts of CRF, as may be released in depression, is compromised in females. Importantly, sex differences in CRF1 function rendered NE neurons in the locus coeruleus of female rats more sensitive to low levels of CRF and less adaptable to high levels of CRF. However, because this is the first report of sex differences in stress- related neuropeptide receptor, many questions remain unanswered. Aim 1 of this proposal, which will be completed during the mentored phase (K99), investigates why CRF1 binds proteins differently in males vs. females. There are no sex differences in CRF1 structure, so I will learn proteomic approaches to identify whether sex differences in post-translational modifications of CRF1 account for these effects. Aims 2 and 3 will be completed during the independent phase. Aim 2 will identify the hormones that contribute to the sex difference in CRF1. To this end, I will combine previously acquired endocrine techniques with the skills learned during the K99 phase to determine whether ovarian or testicular hormones establish the sex differences. Aim 3 will evaluate whether sex differences extend to the other receptor subtype, CRF2, in the dorsal raphe nucleus. Because CRF1 and CRF2 share a high degree of sequence identity, proteomic approaches are expected to reveal sex differences in the CRF2. CRF2 activation of the dorsal raphe-5-HT system promotes a passive behavioral response strategy to stress that is a risk factor for depression. Thus, sex differences in CRF2 may contribute to the increased vulnerability of females this disorder. By addressing these questions, this proposal will help elucidate the etiology of sex differences in stress-related disorders. Moreover, because CRF antagonists are being developed to treat these illnesses, considering sex differences in CRF receptors may increase the efficacy of these compounds in women. PUBLIC HEALTH RELEVANCE: Women are twice as likely as men to suffer from stress-related psychiatric disorders, such as depression and post-traumatic stress disorder, however the biological basis of this sex difference remains unknown. The proposed research will identify molecular and hormonal changes that increase the function of a critical stress-related neuropeptide in female rats. This project will not only help us understand why women are more vulnerable to stress-related mental illnesses, but it will identify new pharmaceutical targets which can lead to treatments that are efficacious in both men and women.