Research Paper Volume 15, Issue 23 pp 13593—13607

Figure 4. (A) Schematic overview of the experimental setup for the infection of human PCLSs with SARS-CoV-2 delta and omicron variant. Created with https://www.biorender.com/. (B) SARS-CoV-2 RNA detected in supernatants of infected human PCLSs after 2 d p.i.. (C) Immunofluorescent staining of mock and infected PCLS. Surfactant protein a (SP-A, green) positive cells are visible in the alveoli of mock and infected slices 4 d p.i.. Colocalization of spike protein (red) and SP-A positive cells in the alveolus of infected slices. Scalebar indicates 100 μm. (D) Gene expression of senescence markers CDKN1A, CDKN2A, and LMNB1, normalized to mock PCLSs. CDKN1A is significantly upregulated in cells infected with omicron variant compared to delta. LMNB1 expression is significantly downregulated in omicron slices compared to delta and mock (E) Levels of the senescence-associated secretory phenotype (SASP) proteins IL-1β, IL-6, IL-8, TNF-α, IL-10 are significantly upregulated in omicron- and delta-infected PCLSs at 2 d p.i. MCP-1 levels are on average highest in omicron-infected slices. P calculated by one-way ANOVA with Multiple comparisons (D, E), ^*p < 0.01, ^**p < 0.05, ^***p < 0.001.