Fig. 1

miR-146a is a miRNA differently expressed in senescent cells and metformin-treated cells. a, b Verification of the anti-senescence effect of metformin in oxidative stress-induced cell senescence. NIH3T3 cells were treated with H₂O₂ (400 μM) for 1 h and incubated in a complete medium with or without metformin (Met, 10 mM) for 3 days. a Representative images of SA-β-gal staining. Scale bar represents 200 μm. b Levels of p-AMPKα1 (pAMPK, Thr172), total AMPKα1, p-ACC (pACC, Ser79), total ACC, p16, and β-actin as detected by immunoblot, with p16 quantification shown (n = 5). c–e Screening of differentially expressed miRNAs increased under H₂O₂-induced senescence and decreased after metformin treatment. c Experimental diagram of miRNA profiling to screen differentially expressed miRNAs in NIH3T3 cells (n = 3). d Heatmap of miRNA profiles in NIH3T3 cells. e DEseq analysis of differentially expressed miRNAs (threshold fold change ≥1.5 and p < 0.05), with the 11 differentially expressed miRNAs shown. f–i Verification of the increased expression of miR-146a in senescent cells. f miR-146a expression in NIH3T3 cells was measured by qRT-PCR (n = 5), the cells were treated as described in a. g, h Replicative senescence was induced in human primary sphenoid sinus mucosa fibroblasts by passaging cells. P8, passage 8. g The levels of p16 and β-actin were detected by immunoblot. h Representative images of SA-β-gal staining in human primary fibroblasts. Scale bar represents 200 μm. i miR-146a expression in human primary fibroblasts (n = 3). j Mice received intraperitoneal (i.p.) injections of D-gal (100 mg/kg/day) daily for 13 weeks to induce progeria, and metformin (100 mg/kg/day, i.p.) was administered to treat mice daily for 13 weeks, and the miR-146a expression was detected in liver tissues (n = 3). k–m Verification of the increased expression of miR-146a in tissues from aged mice. miR-146a expression in liver (n = 5), lung (n = 5), and heart (n = 6) tissues at the indicated months from mice analyzed by qRT-PCR. *p < 0.05, **p < 0.01, ***p < 0.001