LUNG ACE2 AND TMPRSS2 GENE EXPRESSION VARIES WITH ALLERGEN EXPOSURES IN MURINE MODELS OF ASTHMA

ABSTRACT

Introduction: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires angiotensin-converting enzyme 2 (ACE2) and the transmembrane protease, serine 2 (TMPRSS2) for cell entry. Prior studies have reported that allergen exposure can downregulate ACE2 expression. Here, we sought to determine if exposure to distinct combinations of allergens results in the differential expression of ACE2 and TMPRSS2 in the mouse lung. Methods: We utilized three established murine models of asthma 1. Alum/Ovalbumin (OVA) model;2. House dust mite (HDM)/OVA model;3. Mixed-allergen (MA) model using OVA, HDM, Aspergillus fumigatus and Alternaria alternata. Phosphate-buffered saline (PBS) treated mice were used as controls. Lung RNA was extracted using the RNeasy Mini Kit (Qiagen) according to the manufacturer’s protocol, and complementary DNA was synthesized. Quantitative PCR (qPCR) was performed 24 hours after the last challenge utilizing validated primers for ACE2 and TMPRSS2. Analysis was performed using one-way ANOVA. Results: Here we report that ACE2 mRNA expression was lower in the MA and Alum/OVA-treated mice compared to the controls (p-value < 0.0001). No difference was seen in the ACE2 mRNA expression between HDM/OVA and PBS-treated mice. Furthermore, HDM/OVA-treated mice expressed higher levels of TMPRSS2 mRNA compared to controls (p-value < 0.01). No difference was seen in the TMPRSS2 mRNA expression between the MA or Alum/OVA, and the PBS-treated mice. Conclusion: The exposure to distinct combinations of allergens results in unique patterns of ACE2 and TMPRSS2 gene expression in the mouse lung. Further studies are required to evaluate the effects of allergen exposure with the susceptibility to SARS-CoV-2 infection.