Azilsartan Suppressed LPS-Induced Inflammation in U937 Macrophages through Suppressing Oxidative Stress and Inhibiting the TLR2/MyD88 Signal Pathway

Qinglian Dong; Yongxia Li; Juan Chen; Nan Wang

doi:10.1021/acsomega.0c03655

Azilsartan Suppressed LPS-Induced Inflammation in U937 Macrophages through Suppressing Oxidative Stress and Inhibiting the TLR2/MyD88 Signal Pathway

ACS Omega. 2020 Dec 21;6(1):113-118. doi: 10.1021/acsomega.0c03655. eCollection 2021 Jan 12.

Authors

Qinglian Dong¹, Yongxia Li², Juan Chen¹, Nan Wang³

Affiliations

¹ Department of Critical Medicine, Dongying People's Hospital, No. 317, Nanyi Road, Dongying 257091, Shandong, China.
² Department of Stomatology, Dongying People's Hospital, No. 317, Nanyi Road, Dongying 257091, Shandong, China.
³ Department of Nephrology, Dongying People's Hospital, No. 317, Nanyi Road, Dongying 257091, Shandong, China.

Abstract

Background and purpose: Lipopolysaccharide (LPS) is an important factor that induce severe inflammation, resulting in multiple types of diseases. It is reported that LPS-induced inflammation is related to the activation of the NF-κB signal pathway and reactive oxygen species (ROS)-induced oxidative stress. Azilsartan, an angiotensin II type 1 (AT1) receptor blocker, has been licensed as a new generation of Sartan antihypertensive drugs. However, the effects of azilsartan in LPS-induced inflammation have not been reported before. The present study aims to investigate the anti-inflammatory effects of azilsartan on LPS-stimulated macrophages and explore the underlying mechanism.

Methods: The release of lactic dehydrogenase (LDH), secretion of HMGB-1, and concentrations of IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and PGE₂ were evaluated using the enzyme-linked immunosorbent assay (ELISA). The gene expression levels of IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and COX-2 were determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Western blot analysis was used to detect the protein expression level of COX-2, Nrf2, TLR2, MyD-88, and NF-κB. The level of ROS was determined using the dihydroethidium (DHE) staining assay. The activity of NF-κB was evaluated using the luciferase activity assay.

Results: The release of LDH, HMGB-1, IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and PGE₂ was significantly promoted by LPS stimulation, whereas it was greatly suppressed by azilsartan. The upregulated COX-2, TLR2, MyD-88, and NF-κB in the LPS-treated macrophages were significantly downregulated by azilsartan. Interestingly, the expression level of Nrf2 was elevated by azilsartan. On the contrary, ROS levels were greatly increased by LPS but suppressed by azilsartan. Mechanistically, it was found that azilsartan suppressed LPS-induced activation of the TLR2/Myd-88/NF-κB signaling pathway.

Conclusion: Azilsartan might suppress LPS-induced inflammation in U937 macrophages through suppressing oxidative stress and inhibiting the TLR/MyD88 signal pathway.