Fig. 3.

KDAC inhibition reduces cytokine-induced cell death in human islets and resets aberrant cytokine-induced islet cell proinflammatory gene expression. (A) Human islets isolated from three donors were precultured for 1 h with the KDAC inhibitors givinostat (giv, 500 nM) or vorinostat (vori, 1 µM) before adding a combination (Mix) of cytokines (150 pg/mL IL-1β + 10 ng/mL IFN-γ + 50 ng/mL TNF-α). Islets were cultured with Mix for 6 d before determining cell death (Cell Death Detection ELISA; P values indicate comparisons with Mix). (B) IL-1β+ IFN-γ+ TNF-α (Mix) induced iNOS mRNA in isolated human islets with or without vorinostat (vori, 10 μM) preexposure (⁺P < 0.05 vs. Mix, n = 3). (C) INS-1 cells were cultured for 1, 3, or 6 h in the presence (filled bars, CYT) or absence [open bars, Control (Ctrl)] of IL-1β (150 pg/mL) + IFNγ (5 ng/mL). Givinostat (giv, 125 nM) was added 1 h before cytokine exposure (vertically hatched bars). Total RNA was isolated, cDNA was generated by reverse transcription, and expression of genes was quantified by real-time quantitative PCR. Data were normalized to the reference gene Hprt1. Data from four to six independent experiments are presented as mean fold + SEM compared with Ctrl condition with time points indicated. ***P < 0.001 vs. control; ⁺⁺⁺P < 0.05, ⁺⁺P < 0.01, and ⁺P < 0.001 vs. CYT; and ^#P = 0.06 vs. Cyt.