Background Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection-induced inflammatory responses are largely responsible for the death of novel coronavirus disease 2019 (COVID-19) patients. However, the mechanism by which SARS-CoV-2 triggers inflammatory responses remains unclear. Here, we aimed to explore the regulatory role of SARS-CoV-2 spike protein in infected cells and attempted to elucidate the molecular mechanism of SARS-CoV-2-induced inflammation. Methods SARS-CoV-2 spike pseudovirions (SCV-2-S) were generated using the spike-expressing virus packaging system. Western blot, mCherry-GFP-LC3 labeling, immunofluorescence, and RNA-seq were performed to examine the regulatory mechanism of SCV-2-S in autophagic response. The effects of SCV-2-S on apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Western blot, and flow cytometry analysis. Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the mechanism of SCV-2-S in inflammatory responses. Results Angiotensin-converting enzyme 2 (ACE2)-mediated SCV-2-S infection induced autophagy and apoptosis in human bronchial epithelial and microvascular endothelial cells. Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response. Ultimately, SCV-2-S-induced autophagy triggered inflammatory responses and apoptosis in infected cells. These findings not only improve our understanding of the mechanism underlying SARS-CoV-2 infection-induced pathogenic inflammation but also have important implications for developing anti-inflammatory therapies, such as ROS and autophagy inhibitors, for COVID-19 patients.
【저자키워드】 SARS-CoV-2, Apoptosis, Inflammation, COVID-19, Coronavirus disease 2019, ACE2, angiotensin-converting enzyme 2, autophagy, ELISA, enzyme-linked immunosorbent assay, MERS-CoV, Middle East respiratory syndrome coronavirus, IL, interleukin, reactive oxygen species, SARS-COV-2, severe acute respiratory syndrome coronavirus-2, RT-PCR, Reverse transcription polymerase chain reaction, ROS, reactive oxygen species, KEGG, Kyoto encyclopedia of genes and genomes, TNF-α, tumor necrosis factor-alpha, Co-IP, Co-immunoprecipitation, TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling, DEGs, differentially expressed genes, 3-MA, 3-methyladenine,