肺C类纤维在RSV感染早期区域抗病毒免疫反应与后期介导肺部II类免疫反应的作用机制研究

Respiratory syncytial virus (RSV) remains the leading cause of viral bronchiolitis and pneumonia in infants and young children throughout the world. Children with acute RSV infection often develop sequelae of more wheezing episodes. To date, it’s short of safety and effective preventing and therapy strategies for RSV infection. The local immune response in lung plays an important role in the early and later stage post RSV infection in our previous studies. It’s critical to control the excessive production of type 2 associated effectors for preventing repeat wheezing induced by RSV infection. The interaction of sensory nerve and lung immune could cause or accelerate airway diseases. Pulmonary C fibers mainly innervate afferent nerve for respiratory tract. In the present study, we will investigate the effect of PCFs on lung immune antiviral at the early stage of RSV infection, and type 2 response in lung at the later stage, with RSV – infected animal model (BALB/c mice and degenerated – PCFs mice). Moreover, we will uncover that the imbalance of VIP/SP could affect the production of type I interferon producing of airway epithelial cells through VPAC/NK1R to promote antiviral. And then the imbalance of VIP/SP also influences the repair of airway epithelial and the release of epithelial cells – derived cytokines to involve in type 2 response in lung. The results will provide evidence and new intervention strategies for antiviral effects and treatment of airway diseases mediated by type 2 response in lung.

感觉神经与肺区域免疫反应相互作用可导致或加重呼吸系统疾病。肺C类神经纤维（PCFs）是支配呼吸道的主要感觉传入神经。前期研究表明：肺区域免疫反应与RSV感染后急、慢性炎症密切相关, 有效控制过度Ⅱ类因子产生可能是预防RSV感染后反复喘息的关键；建立去除PCFs小鼠模型，发现KPCFs小鼠感染RSV后病毒滴度与气道炎症显著降低，推测PCFs参与RSV感染早期肺部抗病毒效应，后期介导肺部Ⅱ类免疫反应微环境的形成和维持。本研究拟进一步揭示：PCFs激活是否导致VIP/SP失衡，通过与其受体结合，影响RSV感染早期气道上皮细胞I型干扰素产生，参与抗病毒效应？后期是否影响气道上皮细胞修复和上皮细胞源性细胞因子分泌、释放，参与肺部Ⅱ类免疫反应形成？研究结果将进一步阐明肺区域抗病毒免疫应答及其Ⅱ类免疫反应形成和维持的上游通路，为神经激活控制及激活后神经肽物质用于治疗Ⅱ类免疫反应介导的疾病提供理论基础。

RSV是全球范围内引起婴幼儿急性下呼吸道感染最常见和最重要病毒病原体。肺C类神经纤维（PCFs）是支配呼吸道的主要感觉传入神经，前期研究表明：肺区域免疫反应与RSV感染后急、慢性炎症密切相关。本项目以RSV感染去除PCFs（KPCF）小鼠、BALB/c小鼠、巨噬细胞及气道上皮细胞为模型，研究发现：（1）RSV感染KPCF小鼠和BALB/c小鼠后，1）KPCF小鼠BALF中IFN-α/β水平、肺组织TLR3和RIG-1水平、p-STAT1表达、干扰素刺激基因IP-10和MX-1表达均较BALB/c小鼠明显增高；2）KPCF小鼠中抑炎神经肽VIP增加，RSV感染VIPhyb处理KPCF小鼠后，IFN-α/β、p-STAT1、IP-10和MX-1表达均降低，病毒滴度升高；RSV感染VIP、VPAC1激动剂处理BALB/c小鼠后，IFN-α/β、p-STAT1、IP-10和MX-1表达均升高，病毒滴度降低，提示去除PCFs增加的VIP能够诱导机体RSV感染早期内源性I型干扰素产生，促进RSV感染早期抗病毒免疫应答；（2）KPCF小鼠中，肺泡巨噬细胞增加，进而耗竭肺泡巨噬细胞后，BALF中VIP水平明显降低，血清及肠道中VIP水平未降低；RSV感染KPCF并耗竭肺泡巨噬细胞小鼠后，I型干扰素水平明显降低；体外发现VIP处理RSV感染的巨噬细胞后，IFN-α/β水平升高，RIG-1和RIPLET表达增加，提示去除PCFs后，肺泡巨噬细胞是VIP的主要细胞来源，VIP作用于巨噬细胞，通过上调RIG-1和RIPLET表达促进I型干扰素产生。（3）去除PCFs不影响HDM引起的气道上皮细胞和粘液分泌改变。（4）RSV NS1蛋白通过miR-29a介导气道上皮细胞GR的减少，探讨了RSV感染对上皮细胞胞浆激素受体的影响机制。（5）PCFs对RSV感染后II类反应无影响。本研究为下一步寻找病毒感染后抗病毒和气道炎症新方法奠定了基础。标注该项目基金号SCI论文发表3篇，1篇投稿中，在本项目基础上课题负责人获重庆市百千万人才，新增国家自然科学基金地区基金1项，省部级重点项目、一般项目各1项，培养毕业博士研究生2名，在读博士研究生1名。