Complement and tissue factor–enriched neutrophil extracellular traps are key drivers in COVID-19 immunothrombosis
Panagiotis Skendros, … , John D. Lambris, Konstantinos Ritis
Panagiotis Skendros, … , John D. Lambris, Konstantinos Ritis
Published August 6, 2020
Citation Information: J Clin Invest. 2020;130(11):6151-6157. https://doi.org/10.1172/JCI141374.
View: Text | PDF
Concise Communication Immunology

Complement and tissue factor–enriched neutrophil extracellular traps are key drivers in COVID-19 immunothrombosis

Abstract

Emerging data indicate that complement and neutrophils contribute to the maladaptive immune response that fuels hyperinflammation and thrombotic microangiopathy, thereby increasing coronavirus 2019 (COVID-19) mortality. Here, we investigated how complement interacts with the platelet/neutrophil extracellular traps (NETs)/thrombin axis, using COVID-19 specimens, cell-based inhibition studies, and NET/human aortic endothelial cell (HAEC) cocultures. Increased plasma levels of NETs, tissue factor (TF) activity, and sC5b-9 were detected in patients. Neutrophils of patients yielded high TF expression and released NETs carrying active TF. Treatment of control neutrophils with COVID-19 platelet-rich plasma generated TF-bearing NETs that induced thrombotic activity of HAECs. Thrombin or NETosis inhibition or C5aR1 blockade attenuated platelet-mediated NET-driven thrombogenicity. COVID-19 serum induced complement activation in vitro, consistent with high complement activity in clinical samples. Complement C3 inhibition with compstatin Cp40 disrupted TF expression in neutrophils. In conclusion, we provide a mechanistic basis for a pivotal role of complement and NETs in COVID-19 immunothrombosis. This study supports strategies against severe acute respiratory syndrome coronavirus 2 that exploit complement or NETosis inhibition.

Authors

Panagiotis Skendros, Alexandros Mitsios, Akrivi Chrysanthopoulou, Dimitrios C. Mastellos, Simeon Metallidis, Petros Rafailidis, Maria Ntinopoulou, Eleni Sertaridou, Victoria Tsironidou, Christina Tsigalou, Maria Tektonidou, Theocharis Konstantinidis, Charalampos Papagoras, Ioannis Mitroulis, Georgios Germanidis, John D. Lambris, Konstantinos Ritis

×

Figure 1

NETs in the coagulopathy of COVID-19.

Options: View larger image (or click on image) Download as PowerPoint
NETs in the coagulopathy of COVID-19. (A) Myeloperoxidase (MPO)/DNA comp...
(A) Myeloperoxidase (MPO)/DNA complex levels representing NET release in plasma from healthy individuals (controls, n = 10) and patients with COVID-19 (n = 25). (B) Thrombin-antithrombin (TAT) complex levels in plasma from controls and patients with COVID-19. In A and B, red squares indicate severe patients; red triangles, critical patients. (C) Correlation between MPO-DNA levels and TAT levels in patients with COVID-19. (D) Confocal fluorescence microscopy showing TF/neutrophil elastase (NE) staining in control and COVID-19 neutrophils. A representative example of 4 independent experiments is shown. Original magnification: ×600; scale bar: 5 μm. Blue: DAPI; green: TF; red: NE. (E) MPO-DNA levels in NETs isolated from controls and patients with COVID-19. Data are from 4 independent experiments (mean ± SD). (F) TAT levels in plasma from controls treated with NETs isolated from controls and patients with COVID-19. Data are from 4 independent experiments (mean ± SD). (G) Fold expression of TF mRNA in neutrophils isolated from controls and patients with COVID-19. Data are from 4 independent experiments (mean ± SD). D–G were performed in the same 4 patients (identified by an asterisk in Supplemental Table 1). All conditions were compared with controls. *Statistical significance is P < 0.05. A, B: Student’s t test; C: Spearman’s correlation test; E–G: Friedman’s test.