ACE-2 Expression in the Small Airway Epithelia of Smokers and COPD Patients: Implications for COVID-19

Janice M Leung; Chen Xi Yang; Anthony Tam; Tawimas Shaipanich; Tillie L Hackett; Gurpreet K Singhera; Delbert R Dorscheid; Don D Sin

Total RNA was extracted from cytologic brushings using the RNeasy Mini Kit (Qiagen, Hilden, Germany). Transcriptome sequencing was performed on the NovaSeq 6000 (Illumina, San Diego, CA) at a sequencing depth of 55 million reads. Raw sequencing reads were quality controlled with FastQC [9] and aligned to the GENCODE (version 31) GRCh37 genome reference using STAR (Spliced Transcripts Alignment to a Reference) [10] . After alignment, the data were quantified using RSEM (RNA-Seq by Expectation Maximization) to obtain the read counts. Limma voom [11] was applied to normalize the counts to log2 counts per million reads (CPM), which was used in the downstream analysis.