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

Constanze A Jakwerth,Bernhard Haller,Ferdinand M Guerth,Linda Schellhammer,Ulrich M Zissler,Barbara Wollenberg,Carolin Mogler,Martin Feuerherd,Christoph D Spinner,Johanna Giglberger,Thorsten Buch,Claudia Jerin,Carsten B Schmidt-Weber,Luisa Kugler,Lisa Pechtold,Adam M Chaker,Anna Erb,Ulrike Protzer,Madlen Oelsner

doi:10.1007/s00109-022-02182-7

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 B2 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 B2R-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 B2 receptor (B2R) in the nasal mucosa of acutely symptomatic SARS-CoV-2-positive study participants. A B2R-antagonist impeded SARS-CoV-2 replication and spread in NHBEs, as determined in plaque assays on Vero-E6 cells. B2R-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 B2R-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 B2R-antagonists, like icatibant, in the treatment of early-stage COVID-19.Graphical Key messagesInduction of kinin B2 receptor in the nose of SARS-CoV-2-positive patients.Treatment with B2R-antagonist protects airway epithelial cells from SARS-CoV-2.B2R-antagonist reduces ACE2 levels in vivo and ex vivo.Protection by B2R-antagonist is mediated by inhibiting viral replication and spread.

Highlights

SARS-CoV-2 vaccines have been approved worldwide since the end of 2020 and are starting to show their protective effects in public health [1, 2]
To investigate local effects of the acute SARS-CoV-2infection on the nasal epithelium, we analyzed the transcriptome of nasal curettages from symptomatic study participants, who tested acutely positive for SARS-CoV-2 (n = 4), and from SARS-CoV-2-negative study participants (n = 7)
We found that in vitro treatment of NHBEs with B2R-antagonist prior to infection reduced the number of plaque-forming units (PFU) in a plaque assay by 87% (Fig. 1G)

Summary

Introduction

SARS-CoV-2 vaccines have been approved worldwide since the end of 2020 and are starting to show their protective effects in public health [1, 2]. TMPRSS2 cleaves the coronaviral spike protein and primes it for cell fusion, while ACE2 enables the virus particle to enter the cell by binding of its spike protein [9, 10] The latter acts as central component in its function as terminal carboxypeptidase in the counter-regulatory axis of the reninangiotensin-system (RAS) and the contact-activation-system (CAS) [8, 11], which initiates blood coagulation and can activate the kinin-kallikrein-system (KKS) [12]. While DABK is the ligand of B 1R, bradykinin, the end product of the KKS-cascade, activates the constitutively expressed kinin B2 receptor (BDKRB2;B2 receptor;B2R) [18] Through this mechanism, bradykinin mediates its pro-inflammatory effects by eliciting a variety of responses, including vasodilation and edema, via the G protein–triggered phosphatidylinositol-calcium second messenger-system [19–23]. The fact that SARS-CoV-2 utilizes ACE2 to enter airway cells along with the fact that ACE2 is a multifunctional enzyme that counter-regulates the ACEdriven mechanisms of the RAS and balances the KKS may explain the serious course of COVID-19, in the lungs but systemically [24, 25]

Methods

Results

Conclusion