Fig. 7.
miR-34a targets key regulators of cellular senescence, proliferation, and mitochondrial function. A: A549 cells were transfected with 50 nM control (con) or miR-34a mimics. Two days after transfection, levels of Sirt1, cyclin E2, and E2F3 were determined by real-time PCR. Values are means ± SD; n = 4. *P < 0.05 and **P < 0.01 compared with con miR group. B: A549 cells were transfected with 50 nM con inhibitors or inhibitors against miR-34a. Two days after transfection, levels of Sirt1, cyclin E2, and E2F3 were determined by real-time PCR. Values are means ± SD; n = 4. *P < 0.05 compared with the con inhibitor group. C: aged WT and miR-34a−/− mice were intratracheally instilled with bleomycin (BLM). Three weeks after treatment, lung epithelial cells were harvested. Levels of Sirt1, cyclin E2, and E2F3 were determined by real-time PCR. Values are means ± SE; n = 5 and 6 WT and miR-34a−/− mice, respectively. *P < 0.05 compared with BLM WT con. D: ATII conditional knockout mice (miR-34aCKO) and con miR-34afl/fl mice were given tamoxifen (75 mg/kg body wt in 100 μl corn oil) by intraperitoneal injection, followed by intratracheal BLM treatment. Two weeks after BLM treatment, mice were killed, and lung epithelial cells isolated. Levels of Sirt1, cyclin E2, and E2F3 were determined by real-time PCR. Values are means ± SE; n = 5. *P < 0.05 and ***P < 0.001 compared with BLM-injected miR-34afl/fl mice group. E: A549 cells were transduced with con lentiviruses or lentiviruses that expressed human Sirt1. One day after transduction, cells were transfected with 50 nM con mimics or miR-34a mimics for another 48 h. Levels of Sirt1, p21, and PAI-1 in the cells were determined by Western blotting, and densitometric analyses were performed using ImageJ (National Institutes of Health). ***P < 0.001 compared with the con virus, con miR group. #P < 0.05 and ##P < 0.01 compared with the con virus, miR-34a group.