小胶质细胞在广州管圆线虫病中的作用及其机制

Meningitis and meningoencephalitis associated with Angiostrongylus cantonensis(A. cantonensis) infection are characterized by an increase of eosnophils, and eosnophilic activation is the most important pathological basis of brain inflammatory response. In the present study, we find the activation of microglia from mice with infection is consistent with brain inflammatory process. However, no significantly change in brain eosinophil numbers in mice was found after microglial inhibition whereas inflammatory reaction and Neurological Symptoms alleviated obviously. This finding suggests microglia plays an critical role in regulation and maintainance of eosnophilic activation state and function. This study aims to explore the relationship between cerebral eosnophils and microglial activation during A. cantonensis infection in mice, especially the eosnophilic activation state and transformation process when microglia are inhibited, with immunohistochemical staining, flow cytometry, real-time PCR and DNA chip; to confirmed the potential pathway and interaction between activated microglia and eosnophil after the stimulation with worm antigen by cells in vitro, and to demonstrate the modulation of eosnophilic function by microglia and mechanism. Supported by the foundation, this study will reveal the pathogenesis of A. cantonensis, and thus provide the evidence for optimizing present therapy.

广州管圆线虫病是一种新发传染病，主要引起嗜酸性粒细胞（EOS）增多性脑炎和脑膜脑炎，尚无特效治疗方法。EOS的活化是造成脑组织炎症反应的主要病理学基础。我们发现，感染小鼠的小胶质细胞活化与其炎症反应趋势一致；而小胶质细胞被抑制后，小鼠脑组织中EOS数量变化不明显，但炎症反应明显减轻、神经系统症状明显改善，提示小胶质细胞在调控或维持EOS的活化状态和功能中具有关键的作用。为此，本研究以Balb/c小鼠为模型，采用免疫组化、流式细胞检测、real-time PCR和DNA芯片等技术，开展小鼠感染后小胶质细胞和EOS活化状态、表型的动态观察，探讨小胶质细胞被抑制后EOS活化状态及表型变化规律；采用体外实验，进一步验证在虫体抗原刺激下，小胶质细胞活化与EOS活化之间的关联及其信号途径，揭示小胶质细胞对EOS功能的调控作用及其机制，为进一步阐明该病的致病机理和优化现有治疗方案提供实验依据。

广州管圆线虫是一种新发传染病，主要引起嗜酸性粒细胞增高性脑炎和脑膜脑炎，目前尚无特效的治疗方法。EOS粒细胞增多是造成其炎症变化的病理基础。本项目在4年的执行过程中，按照原计划进行。目前完成了（1）系统阐述了广州管圆线虫（Angiostronglus cantonesis, AC）感染后不同时期内小鼠脑内小胶质细胞活化及其变化特征规律： 证实小胶质细胞的活化与AC感染后嗜酸性粒细胞浸润所引起的脑炎发展趋势具有相关性。同时利用米诺环素抑制小胶质细胞活化证实可以减少AC感染后脑内嗜酸性粒细胞，改善广州管圆线虫病的症状。（2）揭示了AC感染后，脑内小胶质细胞活化的机制：证实AC感染后，脑内小胶质细胞活化的方式主要通过IL-33/ST2途径来完成，并利用动物实验，综合分析广州管圆线虫通过IL-33/ST2L途径活化小胶质细胞对广州管圆线虫感染所致嗜酸性粒细胞脑炎具有调节作用。（3）初步揭示了小胶质细胞趋化嗜酸性粒细胞增多的机制：证实AC虫体抗原是诱导脑内小胶质细胞活化的重要因素，其可以促进脑内小胶质细胞分泌Ym1，Ym1具有趋化T细胞、骨髓细胞和嗜酸性粒细胞的活性，从而初步证实其可能是小胶质细胞趋化嗜酸性粒细胞增多的机制。同时初步开展了刺激小胶质细胞活化的AC虫体抗原的组分的鉴定工作。本项目的研究工作初步揭示了小胶质细胞活化在广州管圆线虫感染中的作用，深化了广州管圆线虫感染引起嗜酸性粒细胞增多的机制。项目执行过程中共发表标注SCI论文11篇（第一标注4篇）。