Airway inflammation and fear: neuroimmune mechanisms and forebrain circuits

项目总结： 有效地调节恐惧对于最佳的心理健康至关重要。恐惧失控是后... 创伤应激障碍(PTSD)，一种折磨着22%的退伍军人的衰弱疾病。前额叶受损 皮层(PFC)功能与创伤后应激障碍的恐惧失调有关。并不是所有接触创伤的人都会 创伤后应激障碍提示创伤前的危险因素。弄清这些因素的性质将有助于识别小说 治疗学。最近的证据支持慢性炎症和创伤后应激障碍风险之间的联系。 因此，许多炎症性疾病与创伤后应激障碍的增加有关。越来越多的证据支持一个强有力的 重症哮喘与创伤后应激障碍的关系及其相关因素和机制 与创伤后应激障碍相关的PFC缺陷的调节尚不清楚。我们使用独特鼠标发布的最新数据 空气变应原屋尘螨(HDM)引起的炎症的范例显示出妥协的恐惧 仅在Th17/IL17A扩增的小鼠中消失，这一效应依赖于IL17A受体信号和 外周IL17A。重要的是，这伴随着1)PFC中神经元激活的减少和灭绝- 调节区和2)穹隆下器官(SFO)内的小胶质/T细胞/内皮细胞改变，BBB缺失 投影到PFC的区域。总的来说，这些观察结果提供了我们的假设：严重哮喘与IL-1有关 17A激活SFO内复杂的多细胞信号级联，使PFC参与调节 恐惧。这一假设将在三个目标中得到检验。目标1将确定IL-17A信号和Th17细胞活性 是HDM-Th17/IL17A驱动的恐惧消退缺陷的充要条件，IL-17A的能力 阻断(中和单抗)或Th17拮抗剂(小分子抑制剂)以逆转恐惧消退 Th2/Th17应答或重组IL17A诱导恐惧小鼠的缺陷/神经免疫改变 将评估Th2反应小鼠的消退缺陷/神经免疫改变。目标2将决定 如果SFO-IL预测对于HDM-Th17/IL17A驱动的恐惧消退赤字是必要和充分的 使用逆转录Cre依赖的化学发生策略，我们将抑制或激活SFO-IL投射以评估 Th2与Th2/Th17A对HDM小鼠恐惧消退的影响目标3将鉴定转录 使用单细胞RNAseq的SFO和PFC中与HDM-Th2/Th17效应和恐惧相关的配置文件， SFO和PFC来源的细胞的转录图谱将与免疫的细胞特异性签名一起生成 细胞、胶质细胞、内皮细胞和神经元，以识别在HDM中唯一激活的DEG和信号通路 Th2与Th2/Th17小鼠比较。验证和关联HDM-Th2/Th17对恐惧的影响将使用 Aim 1/Aim 2组织。影响：我们的数据揭示了一种独特的核心机制，即获得性免疫调节剂 与慢性肺部炎症相关，调节皮质缺陷和恐惧，与心理健康有关。 这些研究的完成将扩大我们对外周炎症介质如何调节的理解 大脑功能和行为，并为恐惧相关的病理确定新的风险因素和治疗靶点。

PROJECT SUMMARY: Effective regulation of fear is essential for optimal mental health. Fear dysregulation is a hallmark of post- traumatic stress disorder (PTSD), a debilitating condition afflicting 22% of combat veterans. Impaired prefrontal cortex (PFC) functioning contributes to fear dysregulation in PTSD. Not all trauma-exposed individuals develop PTSD suggesting pre-trauma risk factors. Elucidating the nature of such factors will help identify novel therapeutics. Recent evidence supports an association between chronic inflammation and PTSD risk. Accordingly, many inflammatory diseases are linked to increased PTSD. Growing evidence supports a strong association between severe asthma and PTSD, however the severe asthma associated factors and mechanisms that regulate PTSD relevant PFC deficits remain unknown. Our published and recent data using unique mouse paradigms of aeroallergen house dust mite (HDM)-induced driven inflammation, show compromised fear extinction only in mice with Th17/IL17A expansion, an effect dependent on IL17A receptor signaling and peripheral IL17A. Importantly, this is accompanied by 1) reduced neuronal activation in the PFC an extinction- regulatory area and 2) microglial/T cell/endothelial alterations within the subfornical organ (SFO), a BBB-devoid area projecting to the PFC. Collectively these observations inform our hypothesis: severe asthma relevant IL- 17A activates a complex, multi-cellular signaling cascade within the SFO which engages the PFC to regulate fear. This hypothesis will be tested in 3 aims. Aim 1 will determine if IL-17A signaling, and Th17 cell activity is necessary and sufficient for HDM-Th17/IL17A driven fear extinction deficits The ability of IL-17A blockade (neutralizing mAb) or Th17 antagonism (small molecule inhibitor) to reverse fear extinction deficits/neuroimmune alterations in mice with Th2/Th17 responses, or recombinant IL17A to induce fear extinction deficits/neuroimmune alterations in mice with Th2 responses will be assessed. Aim 2 will determine if SFO?IL projections are necessary and sufficient for HDM-Th17/IL17A driven fear extinction deficits Using a retroCre-dependent chemogenetic strategy we will inhibit or activate SFO?IL projections to assess effects on fear extinction in HDM treated mice with Th2 versus Th2/Th17A Aim 3 will identify transcriptomic profiles in the SFO and PFC associated with HDM-Th2/Th17 effects and fear Using single-cell RNAseq, the transcriptional profile of SFO and PFC derived cells will be generated with cell-specific signatures of immune cells, glia, endothelial cells and neurons to identify DEGs and signaling pathways uniquely activated in HDM TH2 vs Th2/Th17 mice. Validation and association with HDM-Th2/Th17 effects on fear will be performed using Aim 1/Aim 2 tissue. Impact: Our data reveals a unique core mechanism by which adaptive immune mediators associated with chronic lung inflammation regulate cortical deficits and fear, relevant to mental health. Completion of these studies will broaden our understanding of how peripheral inflammatory mediators modulate brain function and behavior and identify novel risk factors and therapeutic targets for fear-associated pathologies.