Fig. 6. Zingerone enhances TIMP4 expression through AMPK phosphorylation. VSMCs were transfected with pc-DNA3.0-AMPK and incubated for 2 days (A, B). VSMCs were cultured with or without Pi, zingerone, and Compound C (1 µM) for 2 days (C). mRNA expression of TIMP4 was measured by real-time polymerase chain reaction (A). Protein levels of TIMP4 measured by Western blot analysis (B, C). Protein levels of TIMP4 were measured by densitometry analysis (B, lower panel and C, right panel). Data represent the mean±standard error of the mean of 3 individual experiments.

TIMP, tissue inhibitor of metalloproteinase; AMPK, AMP-activated protein kinase; VSMC, vascular smooth muscle cell; Pi, inorganic phosphate.

Statistical significance was determined relative to a control (^*p<0.01; ^†p<0.005) or compared with the Pi-treated group (^‡p<0.05) Pi and zingerone group (^§p<0.05) using the Student's t-test.