RAAS antagonists dampen the SARS-CoV-2 infection in ex-vivo cultured human precision-cut lung slices

Abstract Background While the renin-angiotensin-aldosterone system (RAAS) is critically involved in pathomechanisms related to SARS-CoV-2 infection, the role of ongoing therapy with angiotensin-converting enzyme 1 inhibitors (ACEi) or Angiotensin-II type 1 receptor (AT1R) blockers (ARB) is much less clear. We evaluated the effects of the ACEi enalapril (ENA) and the ARB losartan (LOS) on SARS-CoV-2 infection in human ex vivo-cultured, precision-cut lung slices (PCLS) obtained from normal human lung tissue. Methods PCLS were pre-treated for 5d with vehicle, LOS or ENA (300 µM), followed by mock infection or infection with SARS-CoV-2 and incubation with vehicle, LOS or ENA for 1d or 2d. Thereafter, PCLS were harvested for analysis of viral replication, inflammatory responses, endoplasmic reticulum (ER) stress and apoptosis pathways. Results Both LOS and ENA significantly reduced viral replication in PCLS, with ENA being more potent. LOS was more efficient than ENA in reducing the expression of IL1B, CCL2, CXCL2 and TNFA, but not of IL6, whereas ENA preferentially caused a reduction of IL6 and CCL2 in SARS-CoV-2-infected PCLS. Further, ENA, but not LOS, significantly decreased the expression of viral entry factors, ACE2 and transmembrane serine protease 2 (TMPRSS2), in infected PCLS. Importantly, LOS or ENA did not exert cytotoxic effects. Conclusions RAAS-antagonizing drugs do not seem to exert detrimental effects during SARS-CoV-2 infection. In opposite, in an ex-vivo model of human PCLS, such treatment was found to dampen SARS-CoV-2 infection and consecutive inflammation.