尼古丁通过PI3K/Akt/mTOR通路抑制自噬诱导BEAS-2B细胞凋亡

Nicotine Induces Apoptosis of BEAS-2B Cells by Inhibiting Autophagy via the PI3K/Akt/mTOR Pathway

吸烟是慢性呼吸系统炎症疾病最主要危险因素。尼古丁是烟草烟雾中最主要成分,与尼古丁相关的慢性呼吸系统疾病的发病率与日俱增。因此,寻找与尼古丁相关的慢性呼吸系统炎症疾病的潜在靶点是急需解决的问题。本研究旨在探究尼古丁对BEAS-2B细胞凋亡的影响及其潜在作用机制。采用蛋白质印迹法检测各组中的细胞内凋亡、自噬和PI3K/Akt/mTOR通路相关蛋白质的表达。流式细胞术和CCK-8法分别检测各组中细胞凋亡率和细胞活性。结果显示,尼古丁在1 mmol/L、2 mmol/L和4 mmol/L均可诱导BEAS-2B细胞凋亡,且随着浓度增加BEAS-2B细胞活性明显下降。与对照组相比,尼古丁处理后自噬蛋白质LC3Ⅱ和P62表达显著增加(P<0.05);与巴弗洛霉素A1组相比,巴弗洛霉素A1预处理组的LC3Ⅱ蛋白无明显改变(P>0.05)。与尼古丁组相比,雷帕霉素预处理组细胞凋亡明显下降(P<0.05),细胞活性显著升高(P<0.05)。与尼古丁组相比,LY294002预处理组,p-Akt和p-mTOR表达明显降低(P<0.05),细胞凋亡蛋白质表达显著下降(P<0.05)。综上表明,尼古丁可能通过PI3K/Akt/mTOR通路抑制细胞自噬并诱导BEAS-2B细胞凋亡,这可能是预防和治疗与尼古丁相关的慢性呼吸系统炎症疾病的潜在靶点。

Cigarette smoking is a major risk factor for chronic respiratory inflammatory diseases.Nicotine is the most important ingredient in tobacco smoke.The incidence rate of chronic respiratory diseases associated with nicotine is increasing rapidly.Therefore,it is urgent to find potential targets for nicotinerelated chronic respiratory inflammatory diseases.This article hereby aims to investigate the effect of nicotine on apoptosis of BEAS-2B cells and its potential mechanism.The expressions of apoptosis,autophagy and PI3K/Akt/mTOR pathway-related proteins were detected by Western blotting.Flow cytometry and CCK-8 were used to detect cell apoptosis rate and cell viability.The results showed that nicotine induced apoptosis of BEAS-2B cells at 1,2 and 4 mmol/L,and the cell viability decreased with the increase of concentration.Compared with the control group,the expression of autophagy-related protein LC3Ⅱand P62 increased significantly after nicotine treatment(P<0.05).In addition,compared with the baflomycin A1 group,LC3Ⅱof baflomycin A1 pretreatment group was not significantly altered(P>0.05).Compared with the nicotine group,rapamycin pretreatment significantly decreased cell apoptosis and increased cell activity(P<0.05).Compared with the nicotine group,the expression of p-Akt and p-mTOR decreased significantly and apoptosis decreased significantly after LY294002 pretreatment(P<0.05).Furthermore,nicotine induces apoptosis of BEAS-2B cells by inhibiting autophagy may be via PI3K/Akt/mTOR pathway,which may be a potential target for the prevention and treatment of chronic respiratory inflammatory diseases.