Type I IFNs Decrease SARS-CoV-2 Replication in Human Cardiomyocytes and Increase Cytokine Production in Macrophages

The cellular basis of COVID-19 severity in patients with deficiencies in type I IFN immunity remains unclear. In this study, we differentiated cardiomyocytes and macrophages from IFNAR1 competent (IFNAR1^comp) and deficient (IFNAR1^def) induced pluripotent stem cells (iPSCs), and analyzed virus replication and cytokine production after exposure to SARS-CoV-2. Cardiomyocytes expressed the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) and showed abundant SARS-CoV-2 replication, which was higher in IFNAR1^def than IFNAR1^comp cells. Treatment with exogenous IFNα mitigated infection in IFNAR1^comp, but not in IFNAR1^def cardiomyocytes. In contrast, macrophages did not express ACE2 and did not support SARS-CoV-2 replication, but produced pro-inflammatory cytokines upon virus exposure, which was impaired in IFNAR1^def macrophages. In conclusion, type I IFNs decrease SARS-CoV-2 replication in human iPSC-derived cardiomyocytes, while they increase cytokine responses of macrophages.