Figure 1.
Inhibition of PKC-ζ attenuates metformin-enhanced AMPK activity. Confluent BAEC or HUVEC, with or without adenovirus infection, were preincubated with PKC-ζ-PS for 30 minutes before being exposed to metformin. After treatment, the cells were lysaed and extracted. Both phosphorylated AMPK-Thr172 and ACC-Ser79 were detected in Western blots by using specific antibodies, as described in Methods. A, Metformin (Met) activates AMPK in BAEC and HUVEC. The blot is a representative of 6 blots obtained from 6 individual experiments. Con indicates control. B and C, Selective inhibition of PKC-ζ attenuated metformin-enhanced AMPK activity (n=6). ♣P<0.05 (control [Con] vs metformin treated), †P<0.05 (metformin vs metformin plus PKC-ζ-PS). D, PKC-ζ-PS dose-dependently inhibits metformin-enhanced AMPK activity in BAEC (n=5). ♣P<0.05 (control vs metformin), †P<0.05 (metformin vs metformin plus PKC-ζ-PS). E and F, Genetic inhibition of PKC-ζ with PKC-ζ-DN, but not the adenovi-rus encoding GFP, attenuated metformin-enhanced phosphorylation of AMPK-Thr172 and ACC-Ser79 in BAEC. The blot is representative of 5 blots from 5 individual experiments (n=5). ♣P<0.05 (compared with control), †P<0.05 (metformin-treated vs metformin plus adenovirus). G, AMPK activity was assayed as described in Methods (n=4). ♣P<0.05 (compared with control), †P<0.05 (metformin-treated vs metformin plus adenovirus).