miR-34a靶向ATG4B调控上皮细胞自噬在鼻息肉上皮间质转化中的作用研究

Epithelial-mesenchymal transition (EMT) is essential for epithelial remodelling and nasal polypogenesis. It has been observed that autophagy mediated EMT in several chronic inflammations and cancers. However, the exact contribution of autophagy to nasal polyps (NPs) has not been thoroughly investigated. Our preliminary study demonstrated up-regulation of autophagy in epithelial cells of NPs; exposure of hypoxia and NPs extracts promoted autophagy in airway epithelial cells which accompanied EMT; suggesting the role of autophagy in the regulation of EMT in NPs. In addition, we showed that nasal epithelial cells expressed miR-34a, which was markedly lower in the NPs. Transfection with miR-34a agomir or antagomir reagents altered the expression of the autophagic as well as EMT markers. By bioinformatic analysis and luciferase assay, ATG4B was identified as a target of miR-34a. Based on these observation, we hypothesized that miR-34a might attenuates nasal polypogenesis by suppressing autophagy and EMT. Our study herein plans to establish the correlationship between miR-34a, autophagy and EMT, and then determines the regulatory effect of miR-34a and autophagy on EMT in nasal polyps cell and BEAS-2B cell line culture, and in mouse model. Our findings are expected to be benefical for the better understanding of pathogenesis and the improvement in clinical efficacy of nasal polyps.

上皮间质转化(EMT)是鼻黏膜慢性炎症性组织重塑和息肉形成的重要环节。自噬在多种疾病中参与调控EMT，但在鼻息肉中作用未明。我们发现鼻息肉上皮细胞自噬水平升高；低氧和鼻息肉组织液促使上皮细胞自噬增强的同时，发生表型转化；提示自噬可能对鼻黏膜EMT起调控作用。随着越来越多靶向自噬和EMT的miRNA被证实，我们发现miR-34a在鼻息肉上皮细胞中低表达，将其过表达或沉默，自噬和EMT水平也随之改变；并证实miR-34a靶向结合ATG4B；提示miR-34a可能通过调节上皮细胞自噬参与鼻息肉上皮间质转化这一病理生理过程。为此，本项目拟通过组织学研究检测鼻息肉中miR-34a、自噬和EMT三者的相关性，随后借助细胞学研究和小鼠体内试验阐述miR-34a和细胞自噬对鼻黏膜EMT的影响并验证miR-34a调控靶点。本研究将进一步揭示鼻息肉发病的内在机制，为临床防治和新药开发提供理论和实验基础。

上皮间质转化(EMT)是鼻黏膜慢性炎症性组织重塑和息肉形成的重要环节。自噬在多种疾病中参与调控EMT，但在鼻息肉中作用未明。我们研究发现：（1）与正常鼻黏膜相比，p62、Vimentin、collagen I在嗜酸性粒细胞性鼻息肉和非嗜酸性粒细胞性鼻息肉中表达增加，LC3B II/I比例增高，E-cadherin表达减少，证明鼻息肉中存在自噬水平的改变，同时发生上皮间质转化；（2）自噬可能对鼻黏膜EMT起调控作用；（3）miR-34a在鼻息肉中表达异常，其通过靶向ATG4B调控自噬和EMT。本研究进一步揭示了鼻息肉发病的内在机制，有望开发一个具有潜在临床价值的干预靶点，具有较重要的科学价值，也为临床防治和新药开发提供新的思路。