Figure 4. MiR-34a reduces the protein and mRNA expression of SIRT6.

(A) A miR-34a mimic or control was over-expressed for 24 hours and the expression of SIRT1, 2, 3, 4, 5, 6 and 7 assessed (n = 4–7). (B) Lung tissue from resections were obtained from 4 healthy volunteers and 7 COPD Gold stage 4 and RNA extracted, SIRT6 mRNA levels then examined. (C) BEAS2B cells stimulated for 48 hours with H₂O₂ at concentrations of 25, 50, 75, 100 and 150 μM and protein or RNA extracted and changes in SIRT6 gene expression examined (n = 5). (D) SIRT6 protein expression was also assessed (n = 5). (E,F) A miR-34a mimic (15 nM) or control was over-expressed for 24 hours and left un-treated or treated with 100 μM H₂O₂ for 48 hours. RNA or protein was extracted, SIRT6 gene and protein expression assessed (n = 5). A miR-34a antagomir (30 nM) or control was over-expressed for 24 hours and left untreated or treated for 48 hours with 100 μM H₂O₂. RNA or protein was extracted and levels of SIRT6 (G) mRNA (n = 6) or (H) protein were assessed (n = 3–5). (I) Primary bronchial epithelial cells taken from 7 patients with COPD were transfected with either a miR-34a antagomir (30 nM) or control for 24 hours. RNA was extracted and SIRT6 mRNA were detected (n = 7). The band density of each blot is represented as a histogram and is the average of all experiments performed. Data are means ± SEM analyzed by Mann-Whitney, Paired student t-test, Kruskal–Wallis test with post hoc Dunns and One-way Anova with post hoc Bonferroni *P < 0.05, **P < 0.01, ***P < 0.001.