Figure 4

Alterations in ERK, JNK or PI-3K/AKT activity change the promoter activity of PPARγ gene in activated HSC. HSC in six-well plates were co-tranfected with a fixed amount of a DNA mixture per well. It includes 2 μg of pPPARγ-Luc, 0.5 μg pSV-β-gal and a plasmid expressing the active form of a kinase, that is, pa-ERK, pa-JNK, or pwt-PTEN, or a plasmid expressing the dominant negative form of a kinase, that is, pdn-ERK, pdn-JNK, or pdn-PTEN, plus the empty vector pcDNA. The latter was used to ensure the equal amount of total DNA in transfection assays. The amount of DNA of pa-ERK, pa-JNK, or pwt-PTEN plus pcDNA was equalized to 0.7 μg (a and d). The amount of DNA of pdn-ERK, pdn-JNK, or pdn-PTEN plus pcDNA was equalized to 2 μg (b and c). After recovery overnight, cells were serum-starved in DMEM for 24 h before the stimulation with FBS (10%) in the presence or absence of curcumin (20 μM) for an additional 24 h. Luciferase activities were expressed as relative units after β-galactosidase normalization (n≥6). ^*P<0.05 vs cells with no treatment (the corresponding first column on the left). ^‡P<0.05 vs cells with curcumin only, without co-transfected pa-kinase or pdn-PTEN (the corresponding third column on the left).