Fig. 2

miR-146a attenuates the effect of metformin on the alleviation of senescence. a–d NIH3T3 or MRC-5 cells were transfected with miR-146a mimics, or miR-146a inhibitors, or respective controls for 24 h, followed by treatment with H₂O₂ (400 μM) for 1 h and incubated in complete medium with or without metformin (10 mM) for 3 days (n = 5). a, c miR-146a mimics blunted the suppressive effect of metformin on SA-β-gal-positive cells, whereas miR-146a inhibitors worked reversely in senescent NIH3T3 cells and MRC-5 cells. Scale bars represent 200 μm. b, d miR-146a mimics impaired the inhibitory effect of metformin on p16 expression, whereas miR-146a inhibitors worked reversely in senescent NIH3T3 cells and MRC-5 cells. e–h miR-146a regulated replicative senescence in human fibroblasts. The human primary sphenoid sinus mucosa fibroblasts were infected with lentivirus-expressing miR-146a, anti-miR-146a, or the respective controls. Next, replicative senescence was induced by passaging. e, g miR-146a overexpression blunted the suppressive effect of metformin on SA-β-gal-positive cells, whereas anti-miR-146a worked oppositely in human primary fibroblasts (n = 5). Scale bar represents 200 μm. f, h miR-146a impaired the inhibitory effect of metformin on p16 expression, whereas anti-miR-146a worked oppositely in human primary fibroblasts