Activation of cAMP/PKA/CREB engages canonical Wnt and IRS2/Akt signaling in human islets.

<p>(A) & (B) & (C) Human islets (150) were treated for 3 h with CMRL-1066 medium containing 10% FBS, 5 or 20 mM glucose, ± 10 µM forskolin ±5 mM LiCl as indicated. The PKA inhibitor (H-89, 10 µM) and Akt inhibitor (Akt inhibitor XII, 10 µM) were added to the culture where indicated 1 h before stimulation. Cell lysates were prepared and analyzed for CREB-, Akt- and GSK-3 phosphorylation using specific antibodies as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066131#s2" target="_blank">Materials and Methods</a>. In (B) open columns represent pGSK-3α and black columns represent pGSK-3β. (D) Human islets (75) were incubated for 30 min, 4 and 8 h with 5 or 20 mM glucose, ±10 µM forskolin. The levels of mRNA for <i>Nr4a2</i> and <i>Irs2</i> were determined as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066131#s2" target="_blank">Materials and Methods</a>. The values represent the fold change due to the indicated treatment over 5 mM glucose control treatment. Data are the means ± SE of n = 3 experiments. *<i>P</i><0.05 **<i>P</i><0.01 and ***<i>P</i><0.001 denote significant differences between treatment conditions and the respective control (5 mM glucose).