SARS-CoV-2’s nucleocapsid protein modulates macrophage activation






SARS-CoV-2 N Protein Triggers Acute Lung Injury via Modulating Macrophage Activation and Infiltration in in vitro and in vivo

April, 2023 Journal of Inflammation Research

This study looked at how the SARS-CoV-2 virus affects the lungs and whether its nucleocapsid (N) and/or Spike (S) proteins are involved in causing lung damage. The researchers conducted experiments using macrophages (a type of immune cell) in test tubes and in mice.

They found that when alive SARS-CoV-2 virus or N protein (but not S protein) was added to the macrophages, they released high amounts of cytokines (proteins that signal inflammation). The researchers also found that a protein called MyD88 and another called TIRAP were involved in the macrophage activation triggered by N protein. They tested this in mice and found that N protein and dead SARS-CoV-2 caused inflammation and acute lung injury in mice, and that macrophage depletion reduced the cytokine response to N protein. In conclusion, SARS-CoV-2 and its N protein can cause lung damage and inflammation through the activation of macrophages.

Key terms: 
SARS-CoV-2, acute lung injury, nucleocapsid protein, Spike protein, THP-1 macrophages, TICAM2-siRNA, TIRAP-siRNA, MyD88-siRNA, in vitro, in vivo, cytokines, flow cytometry, immunohistochemistry, systemic inflammation, macrophage depletion.