Azithromycin Downregulates Gene Expression of IL-1β and Pathways Involving TMPRSS2 and TMPRSS11D Required by SARS-CoV-2

Background TMPRSS2, ACE2 and TMPRSS11D are genes coding for proteins necessary for SARS-CoV-2 activation, infection and transmission. Once SARS-CoV-2 enters the host cell, it leads to an exaggerated inflammatory state of the lungs mediated by overexpressed TNF-, IL-6, and IL-1β. We assessed azithromycin's effect on the aforementioned genes and their associated pathways to evaluate its potential use as a possible treatment. Objective Confirm the role azithromycin may play in the regulation of pathways and genes involved in inflammation and SARS-CoV-2 activation and cell-to-cell transmission. Methods Primary airway nasal epithelial cells collected from nasal biopsies of three patients with chronic rhinosinusitis (CRS) were primary cultured and treated or not with 10µg of azithromycin. RNA was extracted from these samples and analyzed using a microarray chip. Differential gene expression profiles and gene set enrichment analysis (GSEA) were obtained between both groups. Results Cell cultures treated with 10µg of azithromycin significantly downregulated receptor-mediated endocytosis canonical pathways involving TMPRSS2 and TMPRSS11D genes. Downregulated inflammation-associated genes included IL-1β and NDST1. Interestingly, numerous genes in the cholesterol biosynthesis pathway were significantly upregulated as part of a potential process named drug-induced phospholipidosis (DLP). Conclusions This proof of concept demonstrates azithromycin downregulates pathways involving serine proteases TMPRSS2 and TMPRSS11D required for SARS-CoV-2 activation and its cell-to-cell transmission while downregulating pro-inflammatory cytokine IL-1β, NDST-1 and their associated pathways. This may help reduce the characteristic excessive respiratory epithelial inflammation, key feature of SARS-CoV-2 infection. Finally, azithromycin may also decrease available cholesterol in lipid rafts which may hinder SARS-CoV-2 infection.