Fig. 5.

Mode of action of metformin is partially independent of AMPK signaling. a Schematic representation of the gain-of-function experimental setup for AMPK signaling. b–e qPCR analysis of PLIN2, PPARg, COL1A1, and BMP2 in human IPF lung fibroblasts treated with the AMPK agonist GSK621 or vehicle. f Schematic representation of the loss-of-function experimental setup for AMPK signaling. The decrease of AMPK protein levels at the time of analysis is shown in (g). h–j qPCR analysis of PLIN2, PPARg, and COL1A1 in IPF fibroblasts treated with AMPK siRNA or scramble siRNA. k–m Staining of GSK621- and vehicle-treated cells with LipidTOX (red) and DAPI (blue). Metformin-treated cells were used as a positive control for lipid-droplet accumulation (l). Scale bars: k–m 25 µm. Each data point corresponds to one patient and error bars indicate s.e.m. b–e Vehicle-treated group: n = 8, GSK621-treated group: n = 8. g n = 3 per group. h–j n = 4 per group. Mann–Whitney test was used in (b–e, g) and Kruskal–Wallis test was used in (h–j). *P < 0.05. ns: not significant