Expression of miRNA-24 is increased in pancreatic islet cells. A: Levels of 13 miRNAs in isolated islets from 8-week-old db/db mice (black) were analyzed relative to controls (white). Among them, miR-127, miR-21, miR-30c, miR-375, and miR-7 were statistically significantly downregulated, whereas miR-24, miR-376a, miR-146a, and miR-34a were notably upregulated (P < 0.05). No changes were observed in miR-124a, miR-130a, miR-15a, and miR-181a. U6 small nuclear RNA was used as an internal control to normalize miRNA expression (*P < 0.05 or **P < 0.01 vs. control mice). B: Islets from 8- and 12-week-old db/db mice and controls were isolated, and the expression of miR-24 normalized to U6 was measured using qRT-PCR (*P < 0.05 or **P < 0.01 vs. control mice). The expression of miR-24 increased with age in the islets of db/db mice. Increasing expression levels of miR-24 and miR-34a in islets from HFD-fed mice (n = 5) compared with controls fed the standard diet (SD) (C) (*P < 0.05 or **P < 0.01 vs. SD), palmitate-induced islets (D) (*P < 0.05 or **P < 0.01 vs. ethanol), and in palmitate-treated MIN6 cells (E) (*P < 0.05 vs. ethanol) were observed by TaqMan qRT-PCR relative to corresponding controls. U6 detected by a TaqMan probe was used as an internal control. F: Levels of miR-24 were upregulated in MIN6 cells challenged for various times (12, 24, and 48 h) with (black) or without (white) palmitate
(*P < 0.05 vs. ethanol).