Electronic cigarettes (e-cigs) are battery-operated heating devices that aerosolize e-liquid, typically containing nicotine and several other chemicals, which is then inhaled by a user. Over the past decade, e-cigs have gained immense popularity among both smokers and non-smokers. One reason for this is that they are advertised as a safe alternative to conventional cigarettes. However, the recent reports of e-cig use associated lung injury have ignited a considerable debate about the relative harm and benefits of e-cigs. The number of reports about e-cig-induced inflammation and pulmonary health is increasing as researchers seek to better understand the effects of vaping on human health. In line with this, we investigated the molecular events responsible for the e-cig vapor condensate (ECVC)–mediated inflammation in human lung adenocarcinoma type II epithelial cells (A549). In an attempt to limit the variables caused by longer ingredient lists of flavored e-cigs, tobacco-flavored ECVC (TF-ECVC±nicotine) was employed for this study. Interestingly, we observed significant upregulation of cytokines and chemokines (IL-6, IL-8, and MCP-1) in A549 cells following a 48 h TF-ECVC challenge. Furthermore, there was a significant increase in the expression of pattern recognition receptors TLR-4 and NOD-1, lipid raft–associated protein caveolin-1, and transcription factor NF-кB in TF-ECVC with and/or without nicotine-challenged lung epithelial cells. Our results further demonstrate the harboring of TLR-4 and NOD-1 in the caveolae of TF-ECVC-challenged A549 cells. Proteomic and lipidomic analyses of lipid raft fractions from control and challenged cells revealed a distinct protein and lipid profile in TF-ECVC (w/wo nicotine)-exposed A549 cells. Interestingly, the inflammatory effects of TF-ECVC (w/wo nicotine) were inhibited following the caveolin-1 knockdown, thus demonstrating a critical role of caveolae raft–mediated signaling in eliciting inflammatory responses upon TF-ECVC challenge.

我们研究了导致电子烟蒸气冷凝物 (ECVC) 介导的人肺腺癌 II 型上皮细胞 (A549) 炎症的分子事件。为了限制由较长的调味电子烟成分列表引起的变量，本研究采用了烟草味 ECVC（TF-ECVC±尼古丁）。有趣的是，我们在 48 小时 TF-ECVC 攻击后观察到 A549 细胞中细胞因子和趋化因子（IL-6、IL-8 和 MCP-1）的显着上调。此外，模式识别受体 TLR-4 和 NOD-1、脂筏相关蛋白caveolin-1 和转录因子 NF-кB 在 TF-ECVC 中有和/或没有尼古丁挑战的肺中的表达显着增加上皮细胞。我们的结果进一步证明了 TLR-4 和 NOD-1 在 TF-ECVC 攻击的 A549 细胞的小窝中含有。来自对照细胞和受攻击细胞的脂筏部分的蛋白质组学和脂质组学分析揭示了暴露于 TF-ECVC（w/wo 尼古丁）的 A549 细胞中不同的蛋白质和脂质谱。有趣的是，TF-ECVC（w/wo 尼古丁）的炎症作用在caveolin-1 敲低后受到抑制，从而证明caveolae raft 介导的信号传导在引发TF-ECVC 攻击时的炎症反应中的关键作用。