Abstract: Objective To investigate the mechanism by which angiotensin II-induced oxidative stress response inhibits AMPK/SIRT1 signaling in RAW264.7 macrophages. Methods RAW264.7 cells were treated with 0.5, 1, 3, 10, or 20 μmol/L angiotensin II for 24 h, and the changes in the expressions of AMPK, p-AMPK, and SIRT1 proteins were detected using Western blotting. The intracellular ROS release level was measured and the levels of SOD and MDA were detected. The effects of angiotensin II type 1 receptor (AT1R) gene silencing on the cell response to angiotensin II treatment were examined by detecting the changes in AMPK, p-AMPK and SIRT1 protein levels. The effects of a ROS inhibitor on cellular AMPK and SIRT1 were also examined. Results Angiotensin II stimulation at 20 μmol/L significantly inhibited the phosphorylation of AMPK protein and increased cellular ROS release (P<0.05). Treatment with 0.5-10 μmol/L angiotensin II did not cause significant changes in SOD activity or MDA expression, but angiotensin II at the dose of 20 μmol/L significantly inhibited SOD activity in the cells (P<0.05). In the macrophages with AT1R gene silencing, treatment with angiotensin II did not obviously inhibit AMPK phosphorylation or down- regulate SIRT1 expression. In cells treated with the ROS inhibitor, angiotensin II failed to lower the level of AMPK phosphorylation or the expression of SIRT1. Conclusion Angiotensin II induces oxidative stress to cause disturbance of AMPK/SIRT1 signaling pathway in macrophages.

Key words: angiotensin II; AMPK/SIRT1; RAW264.7 macrophages; oxidative stress