Inhibition of JNK activity reduces glucose-stimulated ADAR2 expression and auto-editing in β-cells.

<p>INS-1 cells maintained at 2.8 mM glucose for 12 hours were cultured without serum for 6 hours at 2.8 mM glucose before pretreatment for 30 min with DMSO (−) or 10 or 20 µM JNK inhibitor SP600125 (JNKi). Cells were then cultured for 3 or 24 hours at 2.8 or 16.7 mM glucose in the presence of DMSO or JNKi at 10 or 20 µM as indicated. (<b>A</b>) The relative mRNA abundance of <i>Adar2</i> was determined by quantitative RT-PCR. Data represent the mean±SEM from three independent experiments. *P<0.05, **P<0.01. (<b>B</b>) Lysates from cells treated for 24 hours were analyzed by immunoblotting using the indicated antibodies. Results are representative of three independent experiments. (<b>C</b>) The efficiency of ADAR2 auto-editing was analyzed by RT-PCR for cells treated for 24 hours. Densitometric quantifications are shown as the mean±SEM (n = 3 independent experiments). *<i>P</i><0.05, **P<0.01.