Airway inflammation and fear: neuroimmune mechanisms and forebrain circuits

项目概要： 有效地调节恐惧对最佳的心理健康至关重要。恐惧失调是后- 创伤性应激障碍（PTSD），一种折磨22%退伍军人的衰弱性疾病。前额叶受损 皮质（PFC）功能有助于PTSD中的恐惧失调。并非所有遭受创伤的人都会发展 创伤后应激障碍提示有创伤前危险因素。阐明这些因素的性质将有助于确定新的 治疗学最近的证据支持慢性炎症和PTSD风险之间的关联。 因此，许多炎症性疾病与PTSD增加有关。越来越多的证据表明， 严重哮喘与创伤后应激障碍之间的关系，但严重哮喘的相关因素和机制 调节PTSD相关PFC缺陷的机制尚不清楚。我们发表的和最近的数据使用独特的鼠标 空气过敏原屋尘螨（HDM）诱导的炎症的范例，显示出妥协的恐惧 仅在Th 17/IL 17 A扩增的小鼠中消退，这是依赖于IL 17 A受体信号传导的作用， 外周血IL 17 A。重要的是，这伴随着1）减少PFC中的神经元激活和灭绝- 调节区和2）穹窿下器官（SFO）内的小胶质细胞/T细胞/内皮细胞改变， 总的来说，这些观察结果为我们的假设提供了依据：严重哮喘相关的IL- 17 A激活SFO内复杂的多细胞信号级联，其参与PFC调节 恐惧这一假设将在3个目标中进行检验。目的1将确定IL-17 A信号传导和Th 17细胞活性是否 是HDM-Th 17/IL 17 A驱动的恐惧消退缺陷的必要和充分条件。 阻断（中和mAb）或Th 17拮抗（小分子抑制剂），以逆转恐惧消退 Th 2/Th 17应答或重组IL 17 A诱导恐惧的小鼠中的免疫缺陷/神经免疫改变 将评估具有Th 2应答的小鼠中的消退缺陷/神经免疫改变。目标2将决定 如果SFO？IL预测对于HDM-Th 17/IL 17 A驱动的恐惧消退缺陷是必要和充分的 使用一个retroCre依赖的化学遗传学策略，我们将抑制或激活SFO？IL预测评估 对HDM处理的小鼠中恐惧消退的影响，其中Th 2与Th 2/Th 17 A的比较 与HDM-Th 2/Th 17效应和恐惧相关的SFO和PFC中的特征 SFO和PFC衍生细胞的转录谱将用免疫细胞化学的细胞特异性特征产生。 细胞、神经胶质细胞、内皮细胞和神经元，以鉴定HDM中唯一激活的DEG和信号通路 TH 2与Th 2/Th 17小鼠。验证和关联HDM-Th 2/Th 17对恐惧的影响将使用 目标1/目标2组织。影响：我们的数据揭示了一种独特的核心机制， 与慢性肺部炎症相关的调节皮质缺陷和恐惧，与心理健康有关。 这些研究的完成将拓宽我们对外周炎症介质如何调节 脑功能和行为，并确定新的风险因素和治疗目标的恐惧相关的病理。

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.