组蛋白去乙酰化酶与T细胞调节对过敏性鼻炎鼻黏膜上皮屏障功能的作用机制研究

Allergic Rhinitis (AR) is a kind of allergic inflammation of nasal mucosa caused by allergens acting on atopic individuals. Nasal epithelia, especially tight junctions (TJs), are the first barrier to prevent environmental allergens from entering the human body and then inducing allergic reactions.Studies have shown that Histone deacetylases (HDACs) have relationship with bronchial epithelial barrier leakiness in asthmatic patients.We also found that the expression of HDACs were up-regulated in nasal epithelia in AR patients.Accordingly, we suggest that the destruction of the nasal epithelial barrier induced by HDAC and T cell regulation may be one of the important factor in the pathogenesis of AR. In this study, we investigate the effects of Th2 cells, Treg cells, their related cytokines (IL-4, IL-5, IL-13, IL-10, etc.) and some inflammatory factors (histamine, leukotriene, platelet activatiing factor) on nasal epithelial barrier function and TJs by testing the trans-membrane resistance (TER), intercellular permeability, expression of TJs mRNA and proteins. And the relationship of those effects with the expression and activity of HDACs was also explored.The successful implementation of this study will help to enrich the pathogenesis of AR research,and further provide a new direction and basis for the clinical prevention and treatment of AR.

过敏性鼻炎（Allergic Rhinitis，AR）是致敏原作用于特应性个体导致鼻黏膜发生的过敏性炎症。鼻黏膜上皮，尤其是上皮细胞紧密连接，是抵御环境致敏原等进入机体，进而诱发过敏反应的第一道屏障。有研究表明：组蛋白去乙酰化酶（Histone deacetylase，HDAC）与哮喘支气管上皮屏障障碍有关，而我们研究发现，HDAC在AR鼻黏膜上皮表达增高。据此，我们提出：HDAC和T细胞调节共同诱导上皮屏障破坏、进而导致AR的发病。研究通过检测上皮细胞跨膜阻力、细胞通透性、紧密连接mRNA及蛋白表达试图揭示Th2、Treg细胞及细胞因子（IL-4、IL-5、IL-13、IL-10等）、炎症因子（组胺、白三烯、血小板活化因子）对鼻黏膜上皮屏障功能和紧密连接的影响以及这种影响与HDAC表达和活性的关系。本研究的顺利实施将有助于丰富AR发病机制的研究，进一步为AR的临床防治提供新的方向和依据。

项目背景：变应性鼻炎（allergic rhinitis, AR）和慢性鼻窦炎伴鼻息肉chronic rhinosinusitis with nasal polyps, CRSwNP作为鼻黏膜的慢性非感染性炎症，其发病机制复杂，目前尚不完全清楚。鼻腔鼻窦黏膜的免疫屏障假说（immune barrier hypothesis）指出，个体包括物理和免疫在内的防御屏障功能的缺失致使病原体得以入侵，从而导致了慢性炎症的发生。而针对黏膜屏障功能的研究也为包括AR和CRSwNP在内的鼻腔鼻窦炎性疾病的发生发展研究提供了新的思路。随着表观遗传学的研究深入，越来越多的学者注意到组蛋白乙酰化和去乙酰化修饰作为组蛋白共价修饰中最为重要的方式，是基因表达调控的重要驱动力。组蛋白去乙酰化酶（histone deacetylases, HDACs）与AR和CRSwNP相关研究甚少。.主要研究内容：本课题主要研究AR和CRSwNP患者黏膜上皮屏障功能和相关蛋白表达情况，以及HDACs对屏障功能的影响、应用HDACs抑制剂后可能产生的作用。.重要结果、关键数据及科学意义：经研究发现，实时荧光定量PCR结果显示紧密连接蛋白claudin-1, claudin-4, claudin-7, occludin, ZO-1和ZO-2 mRNA 在AR鼻黏膜中表达较正常对照组下调，尤其是claudin-7，occludin，ZO-1 和ZO-2；在CRSwNP患者中紧密连接表达较正常对照组下调，并且呈现嗜酸性粒细胞越多，表达越低的趋势。免疫荧光共聚焦显微镜检测发现claudin-1，claudin-4，claudin-7，occludin 和 ZO-1在AR和CRSwNP患者中均表达减弱，对于后者同样有嗜酸性粒细胞越多，表达越低的趋势。实时荧光定量PCR结果显示HDAC1、HDAC9和SIRT7 的mRNA 在AR和CRSwNP中表达较正常对照组上调，并且在CRSwNP组中呈现嗜酸性粒细胞比例越高，表达越多的趋势；免疫组化染色显示同样发现CRSwNP中HDAC1、HDAC9和SIRT7 表达增强，并且在CRSwNP组增强程度与嗜酸粒细胞所占比例呈一定相关性。给予HDACs抑制剂JNJ-26481585后，CRSwNP患者紧密连接表达升高，提示HDACs抑制剂可能作为CRSwNNP甚至AR患者的新的治疗手段。