Figure 5
Binding activity between leptin and activator protein 1 (AP-1) transcription factor and genetic transcription activity at the AP-1-binding site of the leptin promoter increase in HCASMCs under hypoxia. (A) Electrophoretic mobility shift assay (EMSA) showed an increase in binding between leptin and AP-1 in HCASMCs under 2.5% O2 hypoxia. The binding between leptin and AP-1 was suppressed by SP600125 (25 μM), losartan (100 nM), and NAC (500 μM). (B and C) The luciferase reporter assay revealed that 2.5% O2 hypoxia increased the transcriptional activity of AP-I to the leptin promoter compared to the leptin mutant. Transcriptional activity was suppressed by SP600125, NAC, and losartan. Exogenous addition of AngII (10 nM) increased the transcriptional activity of HCASMCs similarly to that of 2.5% O2 hypoxia. *P < 0.01 vs. normoxia control. #P < 0.01 vs. 2 h (n = 3).