Reports indicate an association between COVID-19 and anosmia, as well as the presence of SARS-CoV-2 virions in the olfactory bulb. To test whether the olfactory neuroepithelium may represent a target of the virus, we generated RNA-seq libraries from human olfactory neuroepithelia, in which we found substantial expression of the genes coding for the virus receptor angiotensin-converting enzyme-2 (ACE2) and for the virus internalization enhancer TMPRSS2. We analyzed a human olfactory single-cell RNA-seq dataset and determined that sustentacular cells, which maintain the integrity of olfactory sensory neurons, express ACE2 and TMPRSS2. ACE2 protein was highly expressed in a subset of sustentacular cells in human and mouse olfactory tissues. Finally, we found ACE2 transcripts in specific brain cell types, both in mice and humans. Sustentacular cells thus represent a potential entry door for SARS-CoV-2 in a neuronal sensory system that is in direct connection with the brain.

报告表明，COVID-19 与嗅觉丧失之间存在关联，并且嗅球中存在 SARS-CoV-2 病毒体。为了测试嗅神经上皮是否可能代表病毒的靶点，我们从人类嗅神经上皮中生成了 RNA 序列文库，其中我们发现编码病毒受体血管紧张素转换酶 2 (ACE2) 和病毒内化增强子 TMPRSS2。我们分析了人类嗅觉单细胞 RNA-seq 数据集，并确定维持嗅觉感觉神经元完整性的支持细胞表达ACE2和TMPRSS2。ACE2 蛋白在人和小鼠嗅觉组织的支持细胞亚群中高度表达。最后，我们在小鼠和人类的特定脑细胞类型中发现了ACE2转录本。因此，支持细胞代表了 SARS-CoV-2 在与大脑直接相连的神经元感觉系统中的潜在入口。