ABSTRACT
The newly emerged human coronavirus, SARS-CoV-2, has caused a pandemic of respiratory illness. The innate immune response is critical for protection against Coronaviruses. However, little is known about the interplay between the innate immune system and SARS-CoV-2. Here, we modeled SARS-CoV-2 infection using primary human airway epithelial (pHAE) cultures, which are maintained in an air-liquid interface. We found that SARS-CoV-2 infects and replicates in pHAE cultures and is directionally released on the apical, but not basolateral surface. Transcriptional profiling studies found that infected pHAE cultures had a molecular signature dominated by pro-inflammatory cytokines and chemokine induction, including IL-6, TNFα, CXCL8. We also identified NF-κB and ATF4 transcription factors as key drivers of this pro-inflammatory cytokine response. Surprisingly, we observed a complete lack of a type I or III IFN induction during SARS-CoV-2 infection. Pre-treatment or post-treatment with type I and III IFNs dramatically reduced virus replication in pHAE cultures and this corresponded with an upregulation of antiviral effector genes. Our findings demonstrate that SARS-CoV-2 induces a strong pro-inflammatory cytokine response yet blocks the production of type I and III IFNs. Further, SARS-CoV-2 is sensitive to the effects of type I and III IFNs, demonstrating their potential utility as therapeutic options to treat COVID-19 patients.
IMPORTANCE The current pandemic of respiratory illness, COVID-19, is caused by a recently emerged coronavirus named SARS-CoV-2. This virus infects airway and lung cells causing fever, dry cough, and shortness of breath. Severe cases of COVID-19 can result in lung damage, low blood oxygen levels, and even death. As there are currently no vaccines or antivirals approved for use in humans, studies of the mechanisms of SARS-CoV-2 infection are urgently needed. SARS-CoV-2 infection of primary human airway epithelial cultures induces a strong pro-inflammatory cytokine response yet blocks the production of type I and III IFNs. Further, SARS-CoV-2 is sensitive to the effects of type I and III IFNs, demonstrating their potential utility as therapeutic options to treat COVID-19 patients.
Footnotes
Lead contact: Mehul S. Suthar (mehul.s.suthar{at}emory.edu)
