Abstract
COVID-19, caused by the novel coronavirus SARS-CoV-2, is a global health issue with more than 1 million fatalities to date. Understanding how host factors modify the viral life cycle could inform susceptibility to viral infection and the design of new therapies. Viral replication is shaped by the cellular microenvironment and one important factor is local oxygen tension, where hypoxia inducible factor (HIF) regulates transcriptional responses to hypoxia. SARS-CoV-2 primarily infects cells of the respiratory tract, entering via its Spike glycoprotein binding to angiotensin-converting enzyme (ACE2). We demonstrate that hypoxia and the HIF prolyl hydroxylase inhibitor Roxadustat (FG-4592) reduce ACE2 expression and inhibit SARS-CoV-2 entry and replication in lung epithelial cells via a HIF-1α dependent signalling pathway. Further, hypoxia and Roxadustat inhibit viral replication in SARS-CoV-2 infected cells, showing that post-entry steps in the viral life cycle are oxygen-sensitive. This study highlights the importance of hypoxia and HIF signalling in regulating multiple aspects of SARS-CoV-2 infection and raises the potential use of HIF prolyl hydroxylase inhibitors in the prevention and/or treatment of COVID-19.Funding: The McKeating laboratory is funded by a Wellcome Investigator Award (IA) 200838/Z/16/Z, UK Medical Research Council (MRC) project grant MR/R022011/1 and Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Science (CIFMS), China (grant number: 2018-I2M-2-002). The Ratcliffe laboratory is funded by the Oxford Branch of the Ludwig Institute for Cancer Research; Wellcome IA 106241/Z/14/Z; the Francis Crick Institute, which receives core funding from Cancer Research UK (FC001501), UK MRC (FC001501) and Wellcome (FC001501); the Paradifference Foundation. PJR, EJH and TB are additionally funded by the COVID-19 Research Response Fund, University of Oxford. SK is funded by the Clarendon Scholarships Fund and the Christopher Welch Trust. The Davis laboratory is funded by Wellcome IA 209412/Z/17/Z and Wellcome Strategic Awards 091911/B/10/Z and 107457/Z/15/Z. JYL is funded by the Medial Sciences Graduate Studentship, University of Oxford. The Hinks laboratory is funded by grants from the Wellcome (104553/z/14/z, 211050/Z/18/z) and the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre; the views expressed are those of the authors and not those of the NHS or NIHR. Conflict of Interest: EJH is employed under the Cambridge Experimental Medicine Initiative, which is partly funded by AstraZeneca although they have not been involved in this project. The other authors declare no financial interests.Ethical Approval: The study was reviewed by the Oxford Research Ethics Committee B (18/SC/0361).
Highlights
(TMPRSS2) triggers fusion of the viral and cell membranes (Hoffmann et al, 2020; Wan et al, 2020)
Because the effects of low oxygen on both angiotensin-converting enzyme 2 (ACE2) expression and SARS-CoV-2 replication are likely to be cell context dependent, we evaluated whether hypoxia alters SARS-CoV-2 entry and replication in lung epithelial cells
To define whether hypoxia altered the infectivity of SARS-CoV-2 particles, we assessed the ratio of RNA copies per plaque-forming unit (PFU), finding no significant difference between virus produced from cells at either 18% O2 or 1% O2
Summary
COVID-19, caused by the novel coronavirus SARS-CoV-2, is a global health issue with more than 2 million fatalities to date. SiRNA silencing of HIF-1a, but not HIF-2a, in Calu-3 cells reversed the hypoxic or FG-4592-mediated suppression of viral infection, demonstrating a role for HIF-1a in repressing SARS-CoV-2 RNA replication (Figure 2H) These data show a key role for HIF-1a in repressing ACE2-dependent, authentic SARS-CoV-2 entry and infection. A key finding from our study is the potential therapeutic application of Roxadustat, and other related HIF prolyl hydroxylase inhibitors, in COVID-19, especially because these act on multiple stages of the viral life cycle (impairing entry and replication) and, as such, may be effective against emerging SARS-CoV-2 variants These drugs have been developed as erythropoiesis-stimulating agents in patients with anemic and chronic kidney disease and are currently being used in both pre-dialysis and dialysis settings. B Lead contact B Materials availability B Data and code availability d EXPERIMENTAL MODEL AND SUBJECT DETAILS B Animals B Cell culture B Viral strains d METHOD DETAILS B SARS-CoV-2 pseudoparticle genesis and infection B SARS-CoV-2 propagation and infection B Immunoblotting B RT-qPCR B FISH quantification of SARS-CoV-2 RNA B Image acquisition and analysis B Materials d QUANTIFICATION AND STATISTICAL ANALYSIS
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