The consequences of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can range from asymptomatic to fatal disease. Variations in epithelial susceptibility to SARS-CoV-2 infection depend on the anatomical location from the proximal to distal respiratory tract. However, the cellular biology underlying these variations is not completely understood. Thus, air-liquid interface (ALI) cultures of well-differentiated primary human tracheal and bronchial epithelial cells were employed to study the impact of epithelial cellular composition and differentiation on SARS-CoV-2 infection by transcriptional (RNA sequencing) and immunofluorescent analyses. Changes of cellular composition were investigated by varying time of differentiation or by using specific compounds. We found that SARS-CoV-2 primarily infected ciliated cells but also goblet cells and transient secretory cells. Viral replication was impacted by differences in cellular composition, which depended on culturing time and anatomical origin. A higher percentage of ciliated cells correlated with a higher viral load. However, DAPT-treatment, which increased number of ciliated cells and reduced goblet cells, decreased viral load, indicating the contribution of goblet cells to infection. Cell-entry factors, especially cathepsin L and transmembrane protease serine 2, were also affected by differentiation time. In conclusion, our study demonstrates that viral replication is affected by changes in cellular composition, especially in cells related to the mucociliary system. This could explain in part the variable susceptibility to SARS-CoV-2 infection between individuals and between anatomical locations in the respiratory tract.


中文翻译：

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人类气道上皮细胞组成和分化的变化对 SARS-CoV-2 感染生物学的影响

感染严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 的后果可能从无症状到致命。上皮对 SARS-CoV-2 感染的易感性的变化取决于从近端到远端呼吸道的解剖位置。然而，这些变异背后的细胞生物学尚未完全了解。因此，利用分化良好的原代人气管和支气管上皮细胞的气液界面（ALI）培养物，通过转录（RNA测序）和免疫荧光分析来研究上皮细胞组成和分化对SARS-CoV-2感染的影响。通过改变分化时间或使用特定化合物来研究细胞组成的变化。我们发现 SARS-CoV-2 主要感染纤毛细胞，但也感染杯状细胞和瞬时分泌细胞。病毒复制受到细胞组成差异的影响，这取决于培养时间和解剖学起源。较高百分比的纤毛细胞与较高病毒载量相关。然而，DAPT 治疗增加了纤毛细胞的数量并减少了杯状细胞的数量，从而降低了病毒载量，表明杯状细胞对感染的贡献。细胞进入因子，特别是组织蛋白酶 L 和跨膜蛋白酶丝氨酸 2，也受到分化时间的影响。总之，我们的研究表明，病毒复制受到细胞组成变化的影响，尤其是与粘膜纤毛系统相关的细胞。