SARS‐CoV‐2 viral entry receptor expression is increased in senescent HUVECs. (a) Population doubling times of HUVECs. “Young” (passage 2–5) HUVECs were serially cultured until they entered proliferative arrest at passage 11–14 (Senescent). (b) Non‐senescent (passage 2) and senescent (passage 14) cells were stained for SA‐β‐gal activity (blue cells) and the proliferative marker Ki67 (in red). (c) Real‐time PCR analysis for the senescence marker p16
INK4a
in non‐senescent and senescent cultures. (d, e) quantification of ACE2, DPP4, AGTR1, and AGTR2 mRNA in non‐senescent and senescent cells. GAPDH was used as an internal control. Error bars show mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001, Student's T‐test. f) Western blots for ACE2, DPP4, AGTR1, p16, and actin in non‐senescent (passage 3) and senescent cells (passage 10–12). All real‐time PCR reactions were conducted in triplicate. Data are representative of three (a–d) or two (e) independent experiments