气道上皮细胞ATG5基因对支气管哮喘小鼠气道炎症的抑制作用机制研究

Airway epithelial ATG5 suppresses asthmatic inflammation in mice

目的探讨气道上皮细胞特异性细胞自噬相关基因（ATG5）对支气管哮喘（哮喘）气道损伤和炎症的调控作用。方法将气道上皮细胞clara蛋白10（CCl0）启动Cre系统诱导的ATG5特异性敲除小鼠（atg5^△/△）和对照小鼠（atg5^＋/＋）分别按照数字表法随机分为对照组（atg5^＋/＋-NS组和atg5^△/△-NS组）和哮喘组（atg^△/△-HDM组和atg5^＋/＋-HDM组），用屋尘螨提取物（HDM）构建哮喘模型，检测肺泡灌洗液（BALF）中炎症细胞和嗜酸粒细胞数量、病理、哮喘相关炎症因子表达、黏液分泌以及肺组织细胞自噬、凋亡以及程序性坏死等相关蛋白表达。结果气道上皮细胞特异性ATG5敲除小鼠哮喘模型BALF中炎症细胞总数（171．25＋41．50）和嗜酸粒细胞数量（114．54＋19．61）明显高于对照未敲除小鼠组的（42．64±8．72）和（18．71±7．54）（均P〈0．01），病理结果分析显示atg5^△/△-HDM组小鼠气道周围炎症细胞浸润（2．00±0．45）高于atg5^＋/＋-HDM（1．23±0．26）（P〈0．01），同时atg5A／AHDM辅助性T淋巴细胞2（Th2）相关炎症因子升高以及气道黏液分泌显著增加；ATG5特异性敲除对哮喘模型中肺组织细胞自噬相关蛋白微管相关蛋白1轻链3β（LC3B）和凋亡相关蛋白半胱氨酸天冬氨酸蛋白水解酶（caspase）-9和caspase-3没有明显影响，但显著增加程序性坏死相关受体相互作用蛋白（RIP）和RIP3的表达。结论气道上皮细胞ATG5具有抑制哮喘气道炎症的作用，该作用不依赖于细胞自噬和细胞凋亡，而可能跟细胞的程序性坏死有关。

Objective To explore the role and mechanisms of airway epithelium-localized ATG5 in asthmatic airway injury and inflammation. Methods CC10-rtTA/（tetO）7-ere-ATG5^F/f（atg5^△/△） mice and atg5^＋/＋ mice were randomly assigned to control and asthma groups, respectively. Mice of the asthma group were treated with house dust mite extract （HDM）, and allergic inflammation, mucus hyperproduction, and markers of autophagy, apoptosis, and necroptosis were examined. Results Airway epithelium-specific ATG5 deficiency significantly increased the number of BALF total inflammatory cells （171.25±41.50） and eosinophils （114.54±19.61）, compared with the control asthma group （42.64±8.72） （P〈0.01） and （18.71±7.54） （P〈0.01）, respectively. Histological analyses showed that airway inflammation deteriorated significantly in atg5^△/△ asthma group （2.00±0.45） compared to atg5^＋/＋ group （1.23±0.26） （P〈0.01）. Meanwhile, Th2-related cytokines and mucus production were increased in atg5^△/△ asthma group. These mice displayed enhanced necroptosis markers RIP and RIP3, while the autophagic protein LC3B and apoptotic markers easpase-9 and -3 were not significantly changed. Conclusion Airway epithelium-localized ATG5 suppresses allergic airway inflammation, likely via modulation of necroptosis, while independent of autophagy and apoptosis.