COVID-19 Priority Research Paper Volume 13, Issue 18 pp 21838—21854

SARS-CoV-2 causes senescence in human cells and exacerbates the senescence-associated secretory phenotype through TLR-3

Pseudovirus exposure increases senescence markers in non-senescent cells; these increases in markers were attenuated by TLR-3 inhibitor. (A) Non-senescent kidney endothelial cells and (B) human lung epithelial cells had higher expression of senescence markers and SASP factors upon treatment with pseudovirus, while using TLR-3 inhibitor decreased their expression. Cells were exposed to the pseudovirus in the presence of TLR-3 inhibitor or vehicle (control) for 14 days. (C, D) Activating TLR-3 was not sufficient to induce senescence: TLR-3 agonist did not induce senescence as extensively as the pseudovirus. Non-senescent kidney endothelial (C) and lung epithelial cells (D) were treated with the TLR-3 agonist Poly I:C (2 and 10μg/ml, respectively), for 7 days or pseudovirus, when senescence markers and SASP factor expression were measured. Data are expressed as a function of untreated non-senescent cells; mean +/- SEM, 1-way ANOVA and post hoc comparisons with Fisher’s LSD (A, B) and unpaired Student’s t-tests (C, D).

Figure 2. Pseudovirus exposure increases senescence markers in non-senescent cells; these increases in markers were attenuated by TLR-3 inhibitor. (A) Non-senescent kidney endothelial cells and (B) human lung epithelial cells had higher expression of senescence markers and SASP factors upon treatment with pseudovirus, while using TLR-3 inhibitor decreased their expression. Cells were exposed to the pseudovirus in the presence of TLR-3 inhibitor or vehicle (control) for 14 days. (C, D) Activating TLR-3 was not sufficient to induce senescence: TLR-3 agonist did not induce senescence as extensively as the pseudovirus. Non-senescent kidney endothelial (C) and lung epithelial cells (D) were treated with the TLR-3 agonist Poly I:C (2 and 10μg/ml, respectively), for 7 days or pseudovirus, when senescence markers and SASP factor expression were measured. Data are expressed as a function of untreated non-senescent cells; mean +/- SEM, 1-way ANOVA and post hoc comparisons with Fisher’s LSD (A, B) and unpaired Student’s t-tests (C, D).