EFFECT OF DENERVATION ON THE FUNCTION OF THE AIRWAYS

神经系统调节呼吸道对炎症刺激的反应。这里描述的研究继续对P物质和其他速激肽原(PPT)-A基因编码的速激肽原在这种调节中的作用进行研究。这项拟议的工作将基因改变的小鼠系统应用于：1.确定呼吸道肽能感觉-运动网络的地形组织和分级连通性；2.确定炎症刺激反应中释放的PPT-A速激肽的细胞来源，并阐明三种候选细胞类型(感觉神经元、内源性神经节或造血细胞)对随后的损伤的贡献；以及3.确定PPT-A基因的过度表达本身是否会产生炎症损伤或需要单独的炎症刺激。目标1将通过检测PPT-A 5‘调控区转录控制下的荧光蛋白(ECFP)的表达，并结合使用伪狂犬病病毒作为逆行跨突触标记的跟踪研究来实现。目的2将通过辣椒素选择性化学消融C纤维和在野生型小鼠和PPT-A和NK-1受体基因纯合子纯合子小鼠中进行骨髓重建实验来实现这一点。这些手法的效果将在完整的、炎症的(免疫复合体、仙台病毒和牵张诱导的)和失神经的呼吸道(选择性C纤维消融和异位气管移植)中进行比较。目的3将通过分析PPT-A基因的转基因操作导致PPT-A在呼吸道上皮细胞中异位组成性过表达或在完整和炎症的呼吸道中同位素诱导的PPT-A过表达的效果来实现(见上文)。完成这些目标将提高我们对呼吸道神经源性损伤的理解，并可能有助于开发治疗策略，以最大限度地减少疾病过程中免疫介导的肺部和呼吸道炎症的速激肽放大，如肺移植后的毛细支气管炎或机械通气后的高氧/牵张损伤。

The nervous system modulates the responses of the airways to inflammatory stimuli. The studies described here continue ongoing research into the role of substance P and other preprotachykinin (PPT)-A gene-encoded tachykinins in this modulation. The proposed work applies genetically altered murine systems to: 1. define the topographical organization and hierarchical connectivity of the airway's peptidergic sensory-motor network, 2. identify the cellular origin of the PPT-A tachykinins released in response to inflammatory stimuli and elucidate the contribution of three candidate cell types (sensory neurons, intrinsic ganglia, or hemopoietic cells) to the ensuing injury, and 3. establish whether over-expression of the PPT-A gene can in itself produce an inflammatory injury or requires a separate inflammatory stimulus. Aim 1 will be accomplished by examining the expression of a fluorescent protein (ECFP) placed under the transcriptional control of the PPT-A 5' regulatory region in conjunction with tracking studies using pseudorabies virus as a retrograde trans-synaptic marker. Aim 2 will be approached by a combination of selective chemical ablation of C-fibers by capsaicin and bone marrow reconstitution experiments in wild type mice and mice homozygous for targeted disruptions of the PPT-A and NK-1 receptor genes. The effects of these manipulations will then be compared in intact, inflamed (immune complex, Sendai virus, and stretch-induced), and denervated airways (selective C-fiber ablation and heterotopic tracheal transplantation). Aim 3 will be achieved by analyzing the effects of transgenic manipulations of the PPT-A gene resulting either in ectopic constitutive overexpression of PPT-A in airway epithelial cells or in isotopic inducible over-expression of PPT-A in intact and inflamed airways (see above). Completion of these aims will improve our understanding of airway neurogenic injury and may help to develop therapeutic strategies to minimize tachykinin amplification of immune-mediated inflammation of the lungs and airways in disease processes such as bronchiolitis obliterans after lung transplantation or hyperoxic/stretch injury after mechanical ventilation.