Figure 5. MiR-185 represents a novel replicative senescence biomarker in vitro and in vivo. (A) Young wild-type MRC5 cells were passaged to the old (From PD10 to PD40) and were stained for β-galactosidase activity respectively. (B) The relative expression levels of miR-185 and POT1 in cells from (A) were detected and normalized using U6 and GAPDH levels respectively. (C) MRC5 cells from different passages were cultured, and exosomes were obtained by ultracentrifugation. The relative expression levels of miR-23a and miR-185 were detected and normalized using U6. (D) The relative expression levels of miR-185 from young (males aged 18-30) and old (males aged 50-70) people were detected and normalized using U6 (n=19 and 11 respectively). P values were determined by Student’s t-test. *P<0.05. (E) Proposed model by which miR-185 induces telomere dysfunction and cell senescence via the POT1 pathway.