[Angiotensin Ⅱ inhibits AMPK/SIRT1 pathway by inducing oxidative stress in RAW264.7 macrophages]
1Department of Pharmacy, Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China.
Objective:
To investigate the mechanism by which angiotensin Ⅱ-induced oxidative stress response inhibits AMPK/ SIRT1 signaling in RAW264.7 macrophages.
Objective:
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.
Objective:
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.
Objective:
Angiotensin Ⅱ induces oxidative stress to cause disturbance of AMPK/ SIRT1 signaling pathway in macrophages.
Insights
Angiotensin II causes oxidative stress in macrophages, inhibiting the AMPK/SIRT1 pathway. Blocking the angiotensin II type 1 receptor or using a reactive oxygen species inhibitor prevents this disruption.
Area of Science:
- Cellular and Molecular Biology
- Immunology
- Biochemistry
Background:
- The AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) signaling pathway plays a crucial role in cellular energy homeostasis and stress response.
- Oxidative stress is implicated in the pathogenesis of various inflammatory diseases.
- Angiotensin II is a key mediator in the cardiovascular system and has been linked to oxidative stress.
Purpose of the Study:
- To elucidate the mechanism by which angiotensin II-induced oxidative stress interferes with the AMPK/SIRT1 signaling pathway in RAW264.7 macrophages.
- To investigate the role of the angiotensin II type 1 receptor (AT1R) and reactive oxygen species (ROS) in this process.
Main Methods:
- RAW264.7 macrophages were treated with varying concentrations of angiotensin II.
- Protein expression of AMPK, phosphorylated AMPK (p-AMPK), and SIRT1 was analyzed using Western blotting.
- Intracellular ROS levels, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) levels were measured.
- Experiments involved AT1R gene silencing and the use of a ROS inhibitor.
Main Results:
- High-dose angiotensin II (20 μmol/L) significantly inhibited AMPK phosphorylation and increased ROS production.
- This high dose also significantly reduced SOD activity.
- Silencing the AT1R or using a ROS inhibitor prevented angiotensin II from inhibiting AMPK phosphorylation and downregulating SIRT1 expression.
Conclusions:
- Angiotensin II triggers an oxidative stress response in macrophages, which disrupts the AMPK/SIRT1 signaling pathway.
- The AT1R and ROS are critical mediators in angiotensin II-induced inhibition of the AMPK/SIRT1 pathway.
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