Fatal neuroinvasion and SARS-CoV-2 tropism in K18-hACE2 mice is partially independent on hACE2 expression
ABSTRACTAnimal models recapitulating distinctive features of severe COVID-19 are critical to enhance our understanding of SARS-CoV-2 pathogenesis. Transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) under the cytokeratin 18 promoter (K18-hACE2) represent a lethal model of SARS-CoV-2 infection. The precise mechanisms of lethality in this mouse model remain unclear. Here, we evaluated the spatiotemporal dynamics of SARS-CoV-2 infection for up to 14 days post-infection. Despite infection and moderate pneumonia, rapid clinical decline or death of mice was invariably associated with viral neuroinvasion and direct neuronal injury (including brain and spinal neurons). Neuroinv…
Macrophages govern antiviral responses in human lung tissues protected from SARS-CoV-2 infection
SUMMARYThe majority of SARS-CoV-2 infections among healthy individuals result in asymptomatic to mild disease. However, the immunological mechanisms defining effective lung tissue protection from SARS-CoV-2 infection remain elusive. Unlike mice solely engrafted with human fetal lung xenograft (fLX), mice co-engrafted with fLX and a myeloid-enhanced human immune system (HNFL mice) are protected against SARS-CoV-2 infection, severe inflammation, and histopathology. Effective control of viral infection in HNFL mice associated with significant macrophage infiltration, and the induction of a potent macrophage-mediated interferon response. The pronounced upregulation of the USP18-ISG15 axis (a ne…
Platelet proteome analysis reveals an early hyperactive phenotype in SARS-CoV-2-infected humanized ACE2 mice
AbstractCoronavirus disease-2019 (COVID-19) provokes a hypercoagulable state with increased incidence of thromboembolism and mortality. Platelets are major effectors of thrombosis and hemostasis. Suitable animal models are needed to better understand COVID-19-associated coagulopathy (CAC) and underlying platelet phenotypes. Here, we assessed K18-hACE2 mice undergoing a standardized SARS-CoV-2 infection protocol to study dynamic platelet responses via mass spectrometry-based proteomics. In total, we found significant changes in >1,200 proteins. Strikingly, protein alterations occurred rapidly by 2 days post-infection (dpi) and preceded outward clinical signs of severe disease. Pathway enr…