Secreted ORF8 induces monocytic pro-inflammatory cytokines through NLRP3 pathways in patients with severe COVID-19

Xiaosheng Wu; Michelle K Manske; Gordon J Ruan; Taylor L Witter; Kevin E Nowakowski; Jithma P Abeykoon; Xinyi Tang; Yue Yu; Kimberly A Gwin; Annie Wu; Vanessa Taupin; Vaishali Bhardwaj; Jonas Paludo; Surendra Dasari; Haidong Dong; Stephen M Ansell; Andrew D Badley; Matthew J Schellenberg; Thomas E Witzig

doi:10.1016/j.isci.2023.106929

Secreted ORF8 induces monocytic pro-inflammatory cytokines through NLRP3 pathways in patients with severe COVID-19

iScience. 2023 Jun 16;26(6):106929. doi: 10.1016/j.isci.2023.106929. Epub 2023 May 18.

Authors

Xiaosheng Wu¹, Michelle K Manske¹, Gordon J Ruan¹, Taylor L Witter², Kevin E Nowakowski¹, Jithma P Abeykoon¹, Xinyi Tang¹, Yue Yu³, Kimberly A Gwin¹, Annie Wu⁴, Vanessa Taupin⁵, Vaishali Bhardwaj¹, Jonas Paludo¹, Surendra Dasari³, Haidong Dong⁴, Stephen M Ansell¹, Andrew D Badley⁶, Matthew J Schellenberg², Thomas E Witzig¹

Affiliations

¹ Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
² Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
³ Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55905, USA.
⁴ Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
⁵ Electron Microscopy Core, University of California San Diego, La Jolla, CA, USA.
⁶ Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.

Abstract

Despite extensive research, the specific factor associated with SARS-CoV-2 infection that mediates the life-threatening inflammatory cytokine response in patients with severe COVID-19 remains unidentified. Herein we demonstrate that the virus-encoded Open Reading Frame 8 (ORF8) protein is abundantly secreted as a glycoprotein in vitro and in symptomatic patients with COVID-19. ORF8 specifically binds to the NOD-like receptor family pyrin domain-containing 3 (NLRP3) in CD14⁺ monocytes to induce inflammasomal cytokine/chemokine responses including IL1β, IL8, and CCL2. Levels of ORF8 protein in the blood correlate with severity and disease-specific mortality in patients with acute SARS-CoV-2 infection. Furthermore, the ORF8-induced inflammasome response was readily inhibited by the NLRP3 inhibitor MCC950 in vitro. Our study identifies a dominant cause of pathogenesis, its underlying mechanism, and a potential new treatment strategy for severe COVID-19.

Keywords: Immunity; Virology.