Fig. 3.

Inhibitory effects of exendin-4 (Ex-4), liraglutide (Lira), and dulaglutide (Dula) on the expression of extracellular signal-regulated kinase (Erk) and c-JUN N-terminal kinase (JNK) are mediated by glucagon-like peptide-1 receptor (GLP-1R). A-10 cells pre-exposed to (A) 50 μM Erk inhibitor (PD98059) or (B) 50 μM JNK inhibitor (SP600125) for 1 hour are treated with 1 μM angiotensin II (Ang II), followed by treatment with or without Ex-4 (100 nM), Lira (100 nM), and Dula (100 nM) for 24 hours. (C) A-10 cells, transfected with 50 nM GLP-1R siRNA or scrambled (Scr) siRNA for 24 hours, are treated with Ang II, followed by treatment with or without Ex-4, Lira, and Dula for 24 hours. Expression levels of phosphor-Erk (p-Erk), p-JNK, proliferating cell nuclear antigen (Pcna), and cyclin D1 are analyzed using Western blotting, and glyceraldehyde-3-phosphate dehydrogenase (Gapdh) is used as the loading control. ^aP<0.05 and ^bP<0.01 when compared with the control cells, ^cP<0.05 and ^dP<0.01 when compared with the Ang II-treated cells.