Abstract
BACKGROUND: On March 11, 2020, the World Health Organization (WHO) officially announced that the coronavirus disease 2019 (COVID-19) had reached global pandemic status. Current studies have found that angiotensin-converting enzyme 2 (ACE2) is a cell surface receptor of the novel coronavirus that plays a vital role in the pathogenesis of COVID-19. It is of immense importance for the prevention of virus transmission and treatment to clarify the distribution and expression of ACE2 in various tissues and organs of the body. METHODS: RNAseq transcriptome data and sex data were obtained from the genotype-tissue expression (GTEx) and the Cancer Genome Atlas (TCGA) databases. We separately analyzed the distribution of ACE2 expression in different tissues in the GTEx and TCGA database, and explored the correlation between sex and ACE2 expression levels. Next, the expression levels of ACE2 in different tissues and organs and its correlation with sex were analyzed once again after combing all samples from the two databases. RESULTS: ACE2 expression data were collected from the GTEx database for 6738 normal tissues. Six hundred eighteen tumor tissue data were collected from the TCGA database. The results of the analysis are consistent from different databases. The results indicated that the expression of ACE2 was the highest in the small intestines, higher in tissues such as salivary glands in the testicular, kidney, heart, thyroid and adipose tissues, while the expression of ACE2 was lower in tissues such as the spleen, brain, muscle, pituitary, and skin. There were no significant differences in the expression of ACE2 in the different organs when it came to the individual's sex. CONCLUSIONS: Our study deeply explored the distribution and expression of ACE2 in various tissues of the human body. The tissues and organs with high ACE2 expression were consistent with the current clinical and basic research results of the novel coronavirus. Our study is conducive to the discovery of potential target organs for viral infection, to provide a reference for the development of clinical progress of patients with novel coronavirus infection.