Lipid and Nucleocapsid N-Protein Accumulation in COVID-19 Patient Lung and Infected Cells
Anita E. Grootemaat, Sanne van der Niet, Edwin R. Scholl, Eva Roos, Bernadette Schurink, Marianna Bugiani, Sara Miller, Per Larsen, Jeannette Pankras, Eric A. Reits, Nicole N. van der Wel
Abstract
Visualization of the subcellular localization of SARS-CoV-2 proteins in lung patient material of COVID-19 patients is important for the understanding of this new virus. We detected viral proteins in the context of the ultrastructure of infected cells and tissues and discovered that some viral proteins accumulate in novel, lipid-filled compartments. These structures are induced in Vero cells but, more importantly, also in lung of patients with COVID-19. We have characterized these lipid-filled compartments and determined that this is a novel, virus-induced structure. Immunogold labeling demonstrated that cellular markers, such as CD63 and lipid droplet marker PLIN-2, are absent. Colocalization of lipid-filled compartments with the stable N-protein and nonstructural protein 4 in lung of the last stages of COVID-19 indicates that these compartments play a key role in the devastating immune response that SARS-CoV-2 infections provoke.