Cytokine Signature Induced by SARS-CoV-2 Spike Protein in a Mouse Model

Abstract

Although COVID-19 has become a major challenge to global health, there are currently no efficacious agents for effective treatment. Cytokine storm syndrome (CSS) can lead to acute respiratory distress syndrome (ARDS), which contributes to most COVID-19 mortalities. Research points to interleukin 6 (IL-6) as a crucial signature of the cytokine storm, and the clinical use of the IL-6 inhibitor tocilizumab shows potential for treatment of COVID-19 patient. In this study, we challenged wild-type and adenovirus-5/human angiotensin-converting enzyme 2-expressing BALB/c mice with a combination of polyinosinic-polycytidylic acid and recombinant SARS-CoV-2 spike-extracellular domain protein. High levels of TNF-α and nearly 100 times increased IL-6 were detected at 6 h, but disappeared by 24 h in bronchoalveolar lavage fluid (BALF) following immunostimulant challenge. Lung injury observed by histopathologic changes and magnetic resonance imaging at 24 h indicated that increased TNF-α and IL-6 may initiate CSS in the lung, resulting in the continual production of inflammatory cytokines. We hypothesize that TNF-α and IL-6 may contribute to the occurrence of CSS in COVID-19. We also investigated multiple monoclonal antibodies (mAbs) and inhibitors for neutralizing the pro-inflammatory phenotype of COVID-19: mAbs against IL-1α, IL-6, TNF-α, and granulocyte-macrophage colony-stimulating factor (GM-CSF), and inhibitors of p38 and JAK partially relieved CSS; mAbs against IL-6, TNF-α, and GM-CSF, and inhibitors of p38, extracellular signal-regulated kinase, and myeloperoxidase somewhat reduced neutrophilic alveolitis in the lung. This novel murine model opens a biologically safe, time-saving avenue for clarifying the mechanism of CSS/ARDS in COVID-19 and developing new therapeutic drugs.

Clinical efficacy and safety of Janus kinase inhibitors for COVID-19: A systematic review and meta-analysis of randomized controlled trials

“…The rationale of our findings supporting the repurposing of JAK inhibitors to improve the treatment strategies for COVID-19 could be explained by the following mechanisms. Much evidence has shown that severe COVID-19 patients might present with an exaggerated immune response, characterized by increased interleukin (IL)-6, IL-2, IL-7, IL-10, granulocyte-colony stimulating factor (G-CSF), interferon-γ (IFNγ), macrophage inflammatory protein 1α (MIP1A), and tumor necrosis factor-α (TNF-α) [26] , [27] , [28] , [29] . In contrast, JAK inhibitors targeting JAK1, JAK2, JAK3, and tyrosine kinase-2 (TYK2) can downregulate these cytokines to further decrease inflammatory responses [27] , [28] , [30] .…”

“…Much evidence has shown that severe COVID-19 patients might present with an exaggerated immune response, characterized by increased interleukin (IL)-6, IL-2, IL-7, IL-10, granulocyte-colony stimulating factor (G-CSF), interferon-γ (IFNγ), macrophage inflammatory protein 1α (MIP1A), and tumor necrosis factor-α (TNF-α) [26] , [27] , [28] , [29] . In contrast, JAK inhibitors targeting JAK1, JAK2, JAK3, and tyrosine kinase-2 (TYK2) can downregulate these cytokines to further decrease inflammatory responses [27] , [28] , [30] . In addition, baricitinib (a JAK1/2 inhibitor) may affect the cellular viral entry of SARS-CoV-2 through potential inhibitory effects on AP2-associated protein kinase 1 and cyclin G-associated kinase [31] , [32] .…”

Effect of Ivermectin and Atorvastatin on Nuclear Localization of Importin Alpha and Drug Target Expression Profiling in Host Cells from Nasopharyngeal Swabs of SARS-CoV-2- Positive Patients

“…Additional limitations may arise from the selection of Poly(I:C) to mimic viral infection as opposed to a cell-based infection system when evaluating compounds as potential treatments for SARS-CoV-2 infections. However, extensive reports have provided sound evidence for the use of this model, showcasing how it imitates in vivo responses of the human lung to viral infection, and how it is currently used to assess expression alterations of host cell receptors associated with SARS-CoV-2 [41][42][43][44].…”

Comparative Transcriptomic and Molecular Pathway Analyses of HL-CZ Human Pro-Monocytic Cells Expressing SARS-CoV-2 Spike S1, S2, NP, NSP15 and NSP16 Genes

“…To follow up on the RNA-Seq data, future detailed analyses of selected differently expressed genes and proteins of interest may be conducted by real-time RT-qPCR, Western blotting and other in vitro techniques, and by harnessing gene-knockout and other animal models to further investigate their specific functions in vivo during SARS-CoV-2 infection. Mice expressing human ACE2 and challenged with recombinant SARS-CoV-2 spike protein can elucidate the latter's contribution to COVID-19 pathology [74]. Another strategy for transcriptomic and other analyses is to infect cells expressing human ACE2 receptor with lentiviral particles expressing SARS-CoV-2 proteins, e.g., spike glycoprotein [75].…”