Sex-Hormone Specific Responses to SARS-CoV2 in an iPSC-derived human model of Type 2 Alveolar Epithelial Cells

The chronic phase of SARS-CoV-2 related acute respiratory distress syndrome is characterised by resolution of the acute inflammatory response, fibrosis development and evidence of alveolar epithelial damage. Males are disproportionately affected by severe disease, however, the mechanism for this remains poorly understood. An in vitro human model of iPSC-derived alveolar type 2 cells (iAT2) has been shown to express SARS-CoV-2 entry factors and produce a rapid inflammatory response to SARS-CoV-2 infection. We hypothesise that sex-hormones modulate SARS-CoV2 entry into alveolar cells and augment the fibrotic response in the lung and we can model this process using iAT2. Here, we employ a 3D organoid model of iAT2 to examine sex-hormone responses of AT2 cells in the context of inflammatory and pro-fibrotic gene and microRNA (miRNA) expression. Quantification of miRNA and their predicted targets post sex hormone treatment were measured by qRT-PCR. Estrogen treatment resulted in increased miR-223 expression accompanied by decreased levels of its validated target IL-6, with the opposite effect being observed following testosterone exposure. Similarly, estrogen led to decreased expression of pro-fibrotic genes MMP-7 and CTGF, predicted targets of miR-19a and b respectively, with reciprocal expression of miR-19b. Again, the opposite result was observed with testosterone where MMP-7 and CTGF were found to be increased post treatment. We have shown that we can model sex hormone-specific responses in inflammation and fibrosis genes and related miRNA in iAT2 which may provide an insight into the disproportionate male response to severe SARS-CoV-2 infection.