Sexually dimorphic CNTF/Ucn3 mechanism in fear extinction

项目摘要 恐惧消退缺陷是创伤后应激障碍（PTSD）的标志，暴露疗法可以改善 害怕灭绝。女性患创伤后应激障碍的可能性是男性的两倍，但女性的治疗效果更强。 暴露疗法，其机制尚不清楚。啮齿动物恐惧灭绝学习范式服务于 作为暴露疗法的临床前模型。压力对PTSD有显著影响，并损害恐惧消退。 初步数据表明，慢性不可预测的压力（CUS）诱导的恐惧消退学习的缺陷， 雌性老鼠重要的是，睫状神经营养因子（CNTF）的敲除阻止了这种缺陷，揭示了一种新的免疫缺陷。 CNTF在女性恐惧消退中的新的抑制和有害作用。这项提案也将包括男性。 我们最近的小鼠研究揭示了CNTF在内侧杏仁核（MeA）中对应激的显著性别特异性作用 应答CUS上调CNTF在女性，而不是男性，MeA，这促进应激反应。CUS 不会改变雌性海马体和下丘脑中CNTF的水平。这些数据指向一个女性- 特异性和MeA特异性应激效应。杏仁核，包括MeA， 与恐惧学习有关因此，慢性应激后MeA CNTF的性别特异性调节可能与慢性应激有关。 对恐惧消退的性别特异性影响在大脑中，CNTF由星形胶质细胞及其受体CNTFRα产生， 由星形胶质细胞和神经元表达。CNTF促进成人神经发生并具有神经保护作用。的作用 CNTF在杏仁核中的作用尚不清楚。初步数据显示，敲除CNTF在女性中，而不是男性中， 小鼠增加了神经肽尿皮质素3（Ucn 3），但没有增加Ucn 1和Ucn 2表达的125倍。 杏仁核已知Ucn 3对其受体促肾上腺皮质激素释放因子受体2（CRF-R2）的激活， 纠正压力引起的恐惧学习缺陷。Ucn 3主要在杏仁核的MeA中表达。我们的数据 显示注射到MeA中的CNTF抗体增加了雌性小鼠中的Ucn 3，而不影响雄性。这 提示女性特异性CNTF抑制的MeA Ucn 3可能有助于恐惧消退缺陷。事实上， 女性MeA中Ucn 3减少，可能是由于CNTF增加。我们假设慢性压力引起的 CNTF抑制雌性MeA中Ucn 3的表达，导致恐惧消退学习受损。目标1将定义 MeA CNTF对Ucn 3表达和神经元活性的性别特异性影响。我们将研究 MeA CNTF（1a）和CNTFRα（1b）在调节Ucn 3中的作用。确认CNTF调节的Ucn 3影响CRF-R2 神经元介导应激诱导的恐惧学习缺陷，aim 1c将测量CRF-R2阳性神经元的活性。 CUS和CNTF的MeA内操作后MeA中的神经元。目标2将调查是否 慢性应激调节的MeA CNTF（2a）和Ucn 3（2b）介导每种性别的恐惧消退缺陷。目标2c将 直接定义MeA Ucn 3在慢性应激后CNTF介导的恐惧消退缺陷中的作用。这 一项提案将在MeA中定义一种新的性别特异性CNTF/Ucn 3机制，该机制是压力诱导的恐惧的基础 灭绝缺陷，并使用干预策略，以提高暴露疗法在PTSD的疗效。

Project Summary Fear extinction deficit is a hallmark of post-traumatic stress disorder (PTSD) and exposure therapy improves fear extinction. Women are twice as likely to develop PTSD as men but maintain stronger treatment effects of exposure therapy, and the mechanism is not well understood. Rodent fear extinction learning paradigms serve as preclinical models of exposure therapy. Stress has a significant impact on PTSD and impairs fear extinction. Preliminary data show that chronic unpredictable stress (CUS) induces deficits in fear extinction learning in female mice. Importantly, knockout of ciliary neurotrophic factor (CNTF) prevented this deficit, revealing a novel inhibiting and detrimental role of CNTF in female fear extinction. This proposal will include males as well. Our recent mouse study reveals a striking sex-specific effect of CNTF in the medial amygdala (MeA) on stress responses. CUS upregulates CNTF in female, but not male, MeA, which promotes stress responses. CUS does not alter CNTF levels in the female hippocampus and hypothalamus. These data point to a female- specific and MeA-specific stress effect mediated by CNTF. The amygdala, including the MeA, is strongly associated with fear learning. Thus, sex-specific regulation of MeA CNTF following chronic stress may have a sex-specific effect on fear extinction. In the brain, CNTF is produced by astrocytes and its receptor, CNTFRα, is expressed by astrocytes and neurons. CNTF promotes adult neurogenesis and is neuroprotective. The role of CNTF in the amygdala is not known. Preliminary data show that knockout of CNTF in female, but not male, mice increased the neuropeptide urocortin 3 (Ucn3), but not the >125-fold lower Ucn1 and Ucn2 expression in the amygdala. Ucn3 activation of its receptor, corticotropin releasing factor receptor 2 (CRF-R2), is known to correct stress-induced fear learning deficits. Ucn3 is mainly expressed in the MeA of the amygdala. Our data show that CNTF antibodies injected in the MeA increased Ucn3 in female mice, while not affecting males. This suggests that female-specific CNTF-inhibited MeA Ucn3 might contribute to fear extinction deficit. Indeed, CUS reduced Ucn3 in female MeA, possibly due to increased CNTF. We hypothesize that chronic stress-induced CNTF inhibits Ucn3 expression in the female MeA, causing impaired fear extinction learning. Aim 1 will define the sex-specific effect of MeA CNTF on Ucn3 expression and neuronal activity. We will examine the role of MeA CNTF (1a) and CNTFRα (1b) in regulating Ucn3. To confirm CNTF-regulated Ucn3 affects CRF-R2 neurons that mediate stress-induced fear learning deficit, aim 1c will measure the activity of CRF-R2-positive neurons in the MeA following CUS and intra-MeA manipulation of CNTF. Aim 2 will investigate whether chronic stress-regulated MeA CNTF (2a) and Ucn3 (2b) mediate fear extinction deficits in each sex. Aim 2c will directly define the role of MeA Ucn3 on CNTF-mediated fear extinction deficit following chronic stress. This proposal will define a novel sex-specific CNTF/Ucn3 mechanism in the MeA underlying stress-induced fear extinction deficits and use an intervention strategy to improve the efficacy of exposure therapy in PTSD.