脾相关交感-副交感神经节前神经元对脾免疫功能调节的研究

Diseases caused by pathogen infection have a significant impact on the livestock sector. Improving the immunity of livestock and poultry is one of the best weapons, thus the systematic study of immune regulation is of vital importance for disease prevention and control. The current study shows that there is a close interaction between the nervous system and the immune system. Nervous system could regulate the body immunity through the nerve - endocrine - immune pathway, and regulate the immune system by nerve projection as well. However the mechanism of the regulation is poorly known. This project is based on the preliminary work to involve the following content. Firstly, the neurotropic virus tracer was used to control the mice spleen sympathetic - parasympathetic preganglionic neurons; Secondly, the impact of sympathetic - parasympathetic nerves excitability and inhibition on the immune function of the spleen by specific activating and inhibiting sympathetic - parasympathetic preganglionic neurons using optical genetics and chemical genetics techniques; the effect of sympathetic - parasympathetic nerves on spleen expression profiling and immune-related signaling pathways were analyzed by RNA-Seq technique. Thirdly, the regulation function of sympathetic and parasympathetic nerves in mice and rabbits spleens response to LPS stimulation by inhibiting sympathetic and parasympathetic preganglionic neurons using chemical genetics technique. In short, the project’s development is able to provide the theoretical foundation for the neural system regulation the immune system and improve the immune defense during the pathogen infection.

由病原感染引起的疾病对畜牧业造成巨大影响。提高免疫力是畜禽抵抗病原感染的最好武器，因此系统的研究免疫调节对疾病防控具有重要意义。近年来研究表明神经系统和免疫系统存在密切的互作关系，神经系统不仅可以通过神经-内分泌-免疫途径调节机体免疫力，还能通过神经投射直接调控免疫系统。但目前对神经系统调节免疫系统的机制仍知之甚少。本项目拟在前期工作基础上：（1）利用嗜神经病毒示踪支配小鼠脾的交感-副交感神经节前神经元。（2）利用光遗传学和化学遗传学技术，特异性的激活和抑制脾相关交感-副交感神经节前神经元，研究交感及副交感神经兴奋和抑制对脾免疫功能的影响；结合RNA-Seq技术分析交感-副交感神经对脾表达谱和免疫相关信号通路的影响。（3）利用化学遗传学技术抑制脾相关交感及副交感神经节前神经元，研究交感及副交感神经在小鼠和家兔脾应答LPS刺激的调控功能，为研究神经免疫互作和提高病原感染免疫防御提供理论基础。

由病原感染引起的疾病对畜牧业造成巨大影响。提高免疫力是畜禽抵抗病原感染的最好武器，因此系统的研究免疫调节对疾病防控具有重要意义。近年来研究表明神经系统和免疫系统存在密切的互作关系，神经系统不仅可以通过神经-内分泌-免疫途径调节机体免疫力，还能通过神经投射直接调控免疫系统。神经系统和免疫系统紧密相连，以维持健康和疾病的免疫平衡，但神经系统与免疫系统相互作用的机制和“语言”仍不清楚。本项目研究结果显示：（1）调控脾的交感节前神经元主要分布于脊髓下胸段和腰膨大上段（T11-L2），且荧光信号主要分布于脊髓中间外侧柱。调控脾的副交感节前神经元主要分布于迷走神经背核（DMX）。脾相关的脊髓交感神经节前神经元的激活能够调控脾的免疫功能，并诱导脾产生免疫抑制。交感神经活化能够抑制促炎因子的表达，阻断交感神经系统的活性可以改变机体对抗原和病原体的免疫作用，交感神经能够直接支配淋巴组织，从而影响机体的免疫功能。（2）肾上-腹腔神经节（SrG-CG）内含有调控脾的交感神经，LPS刺激交感神经节肾上-腹腔神经节(SrG-CG)神经元可显著上调NPY的表达。（3）单细胞测序结果显示，SrG-CG中NPY基因的敲除改变了脾淋巴细胞的增殖和活化。（4）在神经元-脾细胞共培养体系中，SrG-CG中的NPY神经元可减弱脾免疫反应。（5）我们发现果蝇的神经元NPF具有保守的免疫调节作用。此外，NPY及其受体中的许多SNPs与人类自身免疫性疾病显著相关。由此证实，NPY是神经-免疫系统互作的古老语言，可能用于缓解感染期间的炎症风暴和调节自身免疫性疾病的免疫平衡。