FIG. 4.

Metformin treatment inhibits the secretion of mature IL-1β and caspase-1 activation in MDMs from patients with type 2 diabetes (T2D). MDMs were isolated from T2D patients (n = 11) before (Before) and after (After) treatment with metformin for 2 months. MDMs were primed with LPS (10 ng/mL) for 4 h, and then stimulated with various ligands: ATP (1 mmol/L for 1 h), MSU (100 μg/mL for 6 h), and FFAs (200 μmol/L for 16 h). A: Western blotting analysis to determine caspase-1 (Casp1) and IL-1β protein levels (cell lysates [Cell], Casp1 p45, and pro-IL-1β [31 kDa]; supernatants [SN], cleaved Casp1 p10, and mature IL-1β [17 kDa]) (A, right). The intensity of each band for each protein was quantified and normalized to the housekeeping gene β-actin. Data are expressed as means ± SEM. ***P < 0.001 vs. control cultures. ELISA analysis of IL-1β (B) and IL-18 (C) levels in supernatants from cultured MDMs. Results are expressed as the mean of triplicate samples. Data are representative of two independent experiments. U, untreated; A, ATP; M, MSU; F, FFAs.