While severe coronavirus infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), cause lung injury with high mortality rates, protective treatment strategies are not approved for clinical use.We elucidated the molecular mechanisms by which the cyclophilin inhibitors cyclosporin A (CsA) and alisporivir (ALV) restrict MERS-CoV to validate their suitability as readily available therapy in MERS-CoV infection.Calu-3 cells and primary human alveolar epithelial cells (hAECs) were infected with MERS-CoV and treated with CsA or ALV or inhibitors targeting cyclophilin inhibitor-regulated molecules including calcineurin, nuclear factor of activated T-cells (NFATs) or mitogen-activated protein kinases. Novel CsA-induced pathways were identified by RNA sequencing and manipulated by gene knockdown or neutralising antibodies. Viral replication was quantified by quantitative real-time PCR and 50% tissue culture infective dose. Data were validated in a murine MERS-CoV infection model.Both CsA and ALV reduced MERS-CoV titres and viral RNA replication in Calu-3 cells and hAECs, improving epithelial integrity. While neither calcineurin nor NFAT inhibition reduced MERS-CoV propagation, blockade of c-Jun N-terminal kinase diminished infectious viral particle release but not RNA accumulation. Importantly, CsA induced interferon regulatory factor 1 (IRF1), a pronounced type III interferon (IFNlambda) response and expression of antiviral genes. Downregulation of IRF1 or IFNlambda increased MERS-CoV propagation in the presence of CsA. Importantly, oral application of CsA reduced MERS-CoV replication in vivo, correlating with elevated lung IFNlambda levels and improved outcome.We provide evidence that cyclophilin inhibitors efficiently decrease MERS-CoV replication in vitro and in vivo via upregulation of inflammatory antiviral cell responses, in particular IFNlambda. CsA might therefore represent a promising candidate for treating MERS-CoV infection.
- Sauerhering, L.
- Kupke, A.
- Meier, L.
- Dietzel, E.
- Hoppe, J.
- Gruber, A. D.
- Gattenloehner, S.
- Witte, B.
- Fink, L.
- Hofmann, N.
- Zimmermann, T.
- Goesmann, A.
- Nist, A.
- Stiewe, T.
- Becker, S.
- Herold, S.
- Peteranderl, C.
Keywords
- Alveolar Epithelial Cells/drug effects/metabolism/virology
- Animals
- Calcineurin Inhibitors/pharmacology
- Cell Culture Techniques
- Coronavirus Infections/metabolism/*prevention & control
- Cyclophilins/*antagonists & inhibitors
- Cyclosporine/*pharmacology
- Disease Models, Animal
- Humans
- Interferon Regulatory Factor-1/drug effects/metabolism
- Interferons/drug effects/*metabolism
- Mice
- Middle East Respiratory Syndrome Coronavirus/*drug effects/physiology
- Virus Replication/drug effects