PM2.5影响呼吸道流感病毒易感性的作用及机制研究

It remains unclear about the effect of acute exposure to PM2.5, a significant source of particulate matter on the susceptibility of human respiratory epithelial cells to influenza virus infections. We have demonstrated that more influenza virus could be detected in PM2.5 exposed mice airway epithelium in the early stage of infection.It has been shown that PM2.5 is able to active the PKC and PI3K kinase which are crucial to influenza virus entry. Therefore, we hypothesized exposure to PM2.5 affects virus entry through Ca2+-RhoA/ROCK or Ca2+-Ras/PI3K pathway. To confirm these theories, we will determine the virus attachment, progeny virus titers, intracellular Ca2+, GTP-RhoA, and GTP-Ras in epithelial cells and mice exposed to PM2.5. We also revisiting those above when Ca2+ chelation, ROCK inhibitor or PI3K inhibitor was given to cells or mice. Finally we expect that the increased susceptibility of human respiratory epithelial cells is contributed by modulating Ca2+-RhoA/ROCK or Ca2+-Ras/PI3K pathway following the exposure to PM2.5. We are hoping to do some help to prevention of PM2.5-related respiratory infection.

PM2.5暴露是否影响气道上皮对流感病毒的易感性，尚不明确。我们前期发现，PM2.5暴露的小鼠在流感病毒感染早期，气道上皮内病毒量明显高于对照组，提示PM2.5暴露增强了气道上皮对流感病毒的易感性。而Ca2+-RhoA/ROCK或Ca2+-Ras/PI3K通路可能在其中扮演重要作用。本研究拟在气道上皮细胞及小鼠模型中，观察不同浓度PM2.5暴露，在流感病毒感染早期的气道上皮内病毒量的变化以及Ca2+-RhoA/ROCK和Ca2+-Ras/PI3K通路变化，并分析其相互之间的关联性。为进一步明确其作用机制，分别采用降低细胞内Ca2+浓度和ROCK、PI3K抑制等手段，以阐明Ca2+-RhoA/ROCK和Ca2+-Ras/PI3K通路在PM2.5暴露影响气道上皮对流感病毒易感性中的作用及其地位，以期为PM2.5诱导的呼吸道病感染的防控提供新思路。

本项目研究证实了气道上皮在不同浓度 PM2.5暴露后对流感病毒易感性增加的现象，并初步明确了Ca2+-RhoA/ROCK以及Ca2+-Ras/PI3K通路在PM2.5暴露增加气道上皮对流感病毒易感性中的作用。在动物模型水平，验证了PM2.5暴露小鼠在感染H3N2流感病毒后，气道上皮内病毒载量明显高于对照组小鼠，并证实了PM2.5暴露并不影响气道上皮IFN-β的表达以及IRF3的磷酸化水平。在细胞水平，发现PM2.5暴露能够增加流感病毒感染早期，细胞内病毒载量升高，并且细胞内Ca2+-RhoA/ROCK和Ca2+-Ras/PI3K通路被激活； 并且随着PM2.5暴露浓度的增加，上述现象更为明显；此外，通过激动PI3K或ROCK活性，能够明显增加气道上皮细胞感染流感病毒早期时细胞内病毒载量；而抑制PI3K或ROCK的激酶活性后，PM2.5暴露并未明显增加气道上皮细胞内流感病毒载量，从而证实PI3K和ROCK激酶参与了PM2.5促进流感病毒感染气道上皮细胞的过程。通过本课题的研究，初步阐明了PM2.5对呼吸道流感病毒易感性的影响和作用机制，为空气污染诱导的呼吸道感染的防控提供新思路。在本课题资助下，相关研究成果在《Chest》、《BMC Medcine》等期刊发表论文5篇（其中SCI论文4篇，中文核心1篇），已投稿论文1篇，待投稿论文2篇。