Figure 6. L-WRN+ promotes crosstalk between Wnt and PKA/CREB and Akt signaling in human islets.

(A) Islets (75) were incubated for 8 h in CMRL-1066 medium containing 10% FBS and 5 mM glucose or in 50% Wnt3a, R-spondin-3 and Noggin conditioned medium (L-WRN)+Y-27632 and SB-431542 inhibitors as indicated. The levels of mRNA for Nr4a2 and Irs2 were determined as described in Material and Method. The values represent the –fold change due the indicated treatment over 5 mM glucose control treatment. (B) Islets (150) were treated for 24 h in CMRL-1066 medium containing 10% FBS and 5 mM glucose ± 5 mM LiCl or in 50% Wnt3a, R-spondin-3 and Noggin conditioned medium (L-WRN) ± Y-27632 and SB-431542 inhibitors. Samples were processed for Western blotting and quantitated by Image Lab™ software. pAkt protein was normalized to total Akt protein. Data are the means ± SE of n = 3. *P<0.05 and **P<0.01 denote significant differences between the treatment condition and respective control. (C) & (D) islets (100) were cultured for 4 days as indicated. ³H-thymidine was added 24 h before the end of the 4-day period. Data are the means ± SE of n = 3 with duplicate samples in each experiment. **P<0.01 and ***P<0.001 denote significant differences between the bracketed condition.