Early reduction of SARS-CoV-2-replication in bronchial epithelium by kinin B2 receptor antagonism

Abstract

Abstract SARS-CoV-2 has evolved to enter the host via the ACE2 receptor which is part of the kinin-kallikrein pathway. This complex pathway is only poorly understood in context of immune regulation but critical to control infection. This study examines SARS-CoV-2-infection and epithelial mechanisms of the kinin-kallikrein-system at the kinin B 2 receptor level in SARS-CoV-2-infection that is of direct translational relevance. From acute SARS-CoV-2-positive study participants and -negative controls, transcriptomes of nasal curettages were analyzed. Primary airway epithelial cells (NHBEs) were infected with SARS-CoV-2 and treated with the approved B 2 R-antagonist icatibant. SARS-CoV-2 RNA RT-qPCR, cytotoxicity assays, plaque assays, and transcriptome analyses were performed. The treatment effect was further studied in a murine airway inflammation model in vivo. Here, we report a broad and strong upregulation of kallikreins and the kinin B 2 receptor (B 2 R) in the nasal mucosa of acutely symptomatic SARS-CoV-2-positive study participants. A B 2 R-antagonist impeded SARS-CoV-2 replication and spread in NHBEs, as determined in plaque assays on Vero-E6 cells. B 2 R-antagonism reduced the expression of SARS-CoV-2 entry receptor ACE2, G protein–coupled receptor signaling, and ion transport in vitro and in a murine airway inflammation in vivo model. In summary, this study provides evidence that treatment with B 2 R-antagonists protects airway epithelial cells from SARS-CoV-2 by inhibiting its replication and spread, through the reduction of ACE2 levels and the interference with several cellular signaling processes. Future clinical studies need to shed light on the airway protection potential of approved B 2 R-antagonists, like icatibant, in the treatment of early-stage COVID-19. Graphical Abstract Key messages Induction of kinin B 2 receptor in the nose of SARS-CoV-2-positive patients. Treatment with B 2 R-antagonist protects airway epithelial cells from SARS-CoV-2. B 2 R-antagonist reduces ACE2 levels in vivo and ex vivo. Protection by B 2 R-antagonist is mediated by inhibiting viral replication and spread.