Begum R, Mutyala D, Thota S, Bidarimath N, Batra S
129 Health Research Center, Laboratory of Pulmonary Immunotoxicology, Department of Environmental Toxicology, Southern University and A&M College, Baton Rouge, LA, 70813, USA.
Arch Toxicol. 2025 Apr 27. doi: 10.1007/s00204-025-03999-0.
Tobacco-based products, including e-cigarettes, have gained popularity as perceived safer alternatives to traditional smoking despite their addictive nature. However, emerging evidence shows that heating e-liquids generates aerosols containing harmful substances, including nicotine, aldehydes, metals, and fine/ultrafine particles. This aerosol composition varies significantly based on device settings, e-liquid ingredients, and heating conditions. E-cigarettes use has been associated with declining lung function, epithelial cell damage, inflammation, and oxidative stress. Previous studies have highlighted and identified the ubiquitin-proteasome system within the lipid raft proteome of murine macrophages, suggesting its role in modulating the NF-κB(p105)-MEK-ERK pathway and inflammatory responses. Based on these findings, our study aimed to investigate the effects of e-cigarette vapors on the compartmentalization of proteasomes. We exposed human type II lung alveolar epithelial cells (A549) to filtered air or tobacco-flavored e-cigarette vapor condensate (TF-ECVC; with or without nicotine) for 24 h. Our findings revealed a notable increase in the transcription and translation of lipid rafts-associated proteins, including Caveolin-1, Caveolin-2, Flotillin-1, and Flotillin-2. We performed subcellular fractionation to elucidate the localization of proteasome/immunoproteasome subunits along with lipid rafts-associated proteins in the membrane and cytosolic fractions. Furthermore, we also observed the localization of proteasome and immunoproteasome subunits within the lipid raft fractions of TF-ECVC-exposed alveolar epithelial cells. Notably, membrane rafts-associated proteins and proteasome subunits were significantly accumulated within exosomes released from the challenged cells. These findings underscore the role of membrane rafts in proteasome compartmentalization and highlight novel molecular mechanisms regulated by ECVC. Furthermore, this study provides critical insights into the potential health risks associated with e-cigarette usage, emphasizing the need for further investigation into its cellular effects.
包括电子烟在内的烟草制品，尽管具有成瘾性，但作为传统吸烟的一种被认为更安全的替代品，已越来越受欢迎。然而，新出现的证据表明，加热电子烟液体会产生含有有害物质的气溶胶，包括尼古丁、醛类、金属以及细/超细颗粒物。这种气溶胶成分会因设备设置、电子烟液成分和加热条件而有显著差异。使用电子烟与肺功能下降、上皮细胞损伤、炎症和氧化应激有关。先前的研究已经突出并确定了小鼠巨噬细胞脂筏蛋白质组中的泛素-蛋白酶体系统，表明其在调节NF-κB(p105)-MEK-ERK途径和炎症反应中的作用。基于这些发现，我们的研究旨在探讨电子烟烟雾对蛋白酶体区室化的影响。我们将人II型肺泡上皮细胞（A549）暴露于过滤空气或烟草味电子烟烟雾冷凝物（TF-ECVC；含或不含尼古丁）中24小时。我们的研究结果显示，与脂筏相关的蛋白质，包括小窝蛋白-1、小窝蛋白-2、 flotillin-1和flotillin-2的转录和翻译显著增加。我们进行了亚细胞分级分离，以阐明蛋白酶体/免疫蛋白酶体亚基以及与脂筏相关的蛋白质在膜和细胞质部分中的定位。此外，我们还观察了暴露于TF-ECVC的肺泡上皮细胞脂筏部分中蛋白酶体和免疫蛋白酶体亚基的定位。值得注意的是，与膜筏相关的蛋白质和蛋白酶体亚基在受刺激细胞释放的外泌体中显著积累。这些发现强调了膜筏在蛋白酶体区室化中的作用，并突出了由ECVC调节的新分子机制。此外，这项研究为与使用电子烟相关的潜在健康风险提供了关键见解，强调需要进一步研究其细胞效应。
