Evidence in humans suggests a correlation between nicotine smoking and severe respiratory symptoms with COVID-19 infection. In lung tissue, angiotensin-converting enzyme 2 (ACE2) appears to mechanistically underlie viral entry. Here, we investigated whether e-cigarette vapor inhalation alters ACE2 and nicotinic acetylcholine receptor (nAChR) expression in male and female mice. In male lung, nicotine vapor inhalation induced a significant increase in ACE2 mRNA and protein, but surprisingly, these differences were not found in females. Further, both vehicle and nicotine vapor inhalation downregulated α5 nAChR subunits in both sexes, while differences were not found in α7 nAChR subunit expression. Finally, blood ACE2 levels did not differ with exposure, indicating that blood sampling is not a sufficient indicator of lung ACE2 changes. Together, these data indicate a direct link between e-cigarette vaping and increased ACE2 expression in male lung tissue, which thereby reveals an underlying mechanism of increased vulnerability to coronavirus infection in individuals vaping nicotine.

人类证据表明，吸尼古丁与感染 COVID-19 的严重呼吸道症状之间存在相关性。在肺组织中，血管紧张素转换酶 2 (ACE2) 似乎是病毒进入的机制基础。在这里，我们研究了电子烟蒸汽吸入是否会改变雄性和雌性小鼠中 ACE2 和烟碱乙酰胆碱受体 (nAChR) 的表达。在男性肺中，吸入尼古丁蒸气会导致 ACE2 mRNA 和蛋白质显着增加，但令人惊讶的是，在女性肺中却没有发现这些差异。此外，媒介物和尼古丁蒸气吸入均下调了两性的 α5 nAChR 亚基，而 α7 nAChR 亚基表达未发现差异。最后，血液 ACE2 水平没有随暴露程度的变化而变化，表明血液采样并不能充分反映肺部 ACE2 的变化。总之，这些数据表明电子烟与男性肺组织中 ACE2 表达增加之间存在直接联系，从而揭示了吸食尼古丁的个体更容易感染冠状病毒的潜在机制。