Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of the respiratory system can progress to a multisystemic disease with aberrant inflammatory response. Cellular senescence promotes chronic inflammation, named senescence-associated secretory phenotype (SASP). We investigated whether coronavirus disease 2019 (COVID-19) is associated with cellular senescence and SASP.
Methods: Autopsy lung tissue samples from 11 COVID-19 patients and 43 age-matched non-COVID-19 controls with similar comorbidities were analysed by immunohistochemistry for SARS-CoV-2, markers of senescence and key SASP cytokines. Virally induced senescence was functionally recapitulated in vitro , by infecting epithelial Vero-E6 cells and a three-dimensional alveosphere system of alveolar type 2 (AT2) cells with SARS-CoV-2 strains isolated from COVID-19 patients.
Results: SARS-CoV-2 was detected by immunocytochemistry and electron microscopy predominantly in AT2 cells. Infected AT2 cells expressed angiotensin-converting enzyme 2 and exhibited increased senescence (p16 INK4A and SenTraGor positivity) and interleukin (IL)-1β and IL-6 expression. In vitro , infection of Vero-E6 cells with SARS-CoV-2 induced senescence (SenTraGor), DNA damage (γ-H2AX) and increased cytokine (IL-1β, IL-6, CXCL8) and apolipoprotein B mRNA-editing (APOBEC) enzyme expression. Next-generation sequencing analysis of progenies obtained from infected/senescent Vero-E6 cells demonstrated APOBEC-mediated SARS-CoV-2 mutations. Dissemination of the SARS-CoV-2-infection and senescence was confirmed in extrapulmonary sites (kidney and liver) of a COVID-19 patient.
Conclusions: We demonstrate that in severe COVID-19, AT2 cells infected by SARS-CoV-2 exhibit senescence and a proinflammatory phenotype. In vitro , SARS-CoV-2 infection induces senescence and inflammation. Importantly, infected senescent cells may act as a source of SARS-CoV-2 mutagenesis mediated by APOBEC enzymes. Therefore, SARS-CoV-2-induced senescence may be an important molecular mechanism of severe COVID-19, disease persistence and mutagenesis.
【초록키워드】 COVID-19, coronavirus disease, severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, Inflammation, immunohistochemistry, Coronavirus disease 2019, coronavirus, Cytokines, severe COVID-19, IL-6, SARS-COV-2 infection, Infection, Comorbidity, senescence, cytokine, in vitro, molecular mechanism, severe acute respiratory syndrome Coronavirus, angiotensin-converting enzyme 2, kidney, DNA damage, proinflammatory, electron microscopy, cells, persistence, Microscopy, Apolipoprotein B, Control, phenotype, APOBEC, chronic inflammation, Respiratory system, SARS-CoV-2 mutations, respiratory, Enzymes, disease, expression, epithelial, Strains, liver, COVID-19 patients, CXCL8, Angiotensin-converting enzyme, cellular senescence, marker, IL-1β, Mutagenesis, Inflammatory response, AT2, angiotensin, COVID-19 patient, Non-COVID-19, acute respiratory syndrome, acute respiratory syndrome coronavirus, enzyme, SARS-CoV-2 strains, SARS-CoV-2 mutagenesis, SARS-CoV-2 strain, IL-6 expression, Sequencing analysis, progeny, SASP, H2Ax, Vero-E6 cells, alveolar, immunocytochemistry, infecting, extrapulmonary sites, Cell, multisystemic disease, investigated, analysed, exhibited, expressed, demonstrated, promote, induce, lung tissue sample, senescent cell, Vero-E6 cell, 【제목키워드】 SARS-CoV-2, Infection, pulmonary, Viral mutagenesis, inflammatory phenotype, implication, induce, accompanied,