5-Methoxyflavone alleviates LPS-mediated lung injury by promoting Nrf2-mediated the suppression of NOX4/TLR4 axis in bronchial epithelial cells and M1 polarization in macrophages

Journal of Inflammation

Research

Yuehan Zhang¹  Beixian Zhou¹  Panqiao Liang²  Yueyun Liang³  Sushan Yang⁴  Jiashun Li⁵  Linxin Wang⁶  Xiping Pan⁶  Jing Li⁷ 

[1] Center of Stem Cell and Regenerative Medicine, The People’s Hospital of Gaozhou, 525200, Gaozhou, China;Center of Stem Cell and Regenerative Medicine, The People’s Hospital of Gaozhou, 525200, Gaozhou, China;Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou Medical University, 511436, Guangzhou, China;Department of Anesthesiology, The People’s Hospital of Gaozhou, 525200, Gaozhou, China;Department of Clinical Laboratory, The People’s Hospital of Gaozhou, 525200, Gaozhou, China;Department of Respiratory, Affiliated Huadu Hospital, Southern Medical University (People’s Hospital of Huadu District), 510800, Huadu, China;Guangzhou Laboratory, Guangzhou, China;State Key Laboratory of Respiratory Disease, National Clinical Research Center of Respiratory Disease, Guangzhou Institute of Respiratory Health, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China;Institute of Chinese Integrative Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China;

关键词: Methylated flavonoid;    5-Methoxyflavone;    Nrf2;    LPS;    Acute lung injury;   

DOI  :  10.1186/s12950-022-00319-6

 received in 2022-05-16, accepted in 2022-11-10,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundAcute lung injury (ALI) arises from sepsis or bacterial infection, which are life-threatening respiratory disorders that cause the leading cause of death worldwide. 5-Methoxyflavone, a methylated flavonoid, is gaining increased attention for its various health benefits. In the current study, we investigated the potential effects of 5-methoxyflavone against LPS-mediated ALI and elucidated the corresponding possible mechanism.MethodsA mouse model with ALI was established by intratracheal instillation of LPS, and lung pathological changes, signaling pathway related proteins and apoptosis in lung tissues were estimated by H&E staining, immunofluorescence and TUNEL assay, respectively. Cell viability was evaluated by MTT assay; protein levels of pro-inflammatory mediators were measured by ELISA assay; levels of ROS and M1 macrophage polarization were assayed by flow cytometry; the expression of Nrf2 signaling, NOX4/TLR4 axis and P-STAT1 were detected by western blotting.ResultsOur results showed that 5-methoxyflavone treatment inhibited LPS-induced expression of NOX4 and TLR4 as well as the activation of downstream signaling (NF-κB and P38 MAPK), which was accompanied by markedly decreased ROS levels and pro-inflammatory cytokines (IL-6, TNF-α, MCP-1, and IL-8) in BEAS-2B cells. Moreover, we revealed that these effects of 5-methoxyflavone were related to its Nrf2 activating property, and blockade of Nrf2 prevented its inhibitory effects on NOX4/TLR4/NF-κB/P38 MAPK signaling, thus abrogating the anti-inflammatory effects of 5-methoxyflavone. Besides, the Nrf2 activating property of 5-methoxyflavone in RAW264.7 cells led to inhibition of LPS/IFN-γ-mediated STAT1 signaling, resulting in suppression of LPS/IFN-γ-induced M1 macrophage polarization and the repolarization of M2 macrophages to M1. In a mouse model of LPS-induced ALI, 5-methoxyflavone administration ameliorated LPS-mediated lung pathological changes, the increased lung index (lung/body weight ratio), and epithelial cell apoptosis. Meanwhile, we found 5-methoxyflavone effectively suppressed the hyperactive signaling pathways and the production of excessive pro-inflammatory mediators. Moreover, 5-methoxyflavone reduced LPS-mediated M1 macrophage polarization associated with elevated P-STAT1 activation in the lung tissues. In addition, 5-methoxyflavone improved the survival of LPS-challenged mice.ConclusionThese results indicated that 5-methoxyflavone might be suitable for the development of a novel drug for ALI therapeutic.

【 授权许可】

CC BY   
© The Author(s) 2022

【 图 表 】

Fig. 5

Fig. 5

Fig. 3

Fig. 1

Fig. 1

41408_2022_764_Article_IEq30.gif