20-Hydroxy-3-Oxolupan-28-Oic Acid Attenuates Inflammatory Responses by Regulating PI3K–Akt and MAPKs Signaling Pathways in LPS-Stimulated RAW264.7 Macrophages

• Main Authors: Yufeng Cao, Fu Li, Yanyan Luo, Liang Zhang, Shuya Lu, Rui Xing, Bingjun Yan, Hongyin Zhang, Weicheng Hu
• Format: Article
• Language: English
• Published: MDPI AG 2019-01-01
• Series: Molecules
• Subjects: inflammation; nitric oxide; macrophage; NF-κB; lupane-type triterpene
• Online Access: https://www.mdpi.com/1420-3049/24/3/386

20-Hydroxy-3-oxolupan-28-oic acid (HOA), a lupane-type triterpene, was obtained from the leaves of <i>Mahonia bealei</i>, which is described in the Chinese Pharmacopeia as a remedy for inflammation and related diseases. The anti-inflammatory mechanisms of HOA, however, have not yet been fully elucidated. Therefore, the objective of this study was to characterize the molecular mechanisms of HOA in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. HOA suppressed the release of nitric oxide (NO), pro-inflammatory cytokine tumor necrosis factor &#945; (TNF-&#945;), and interleukin 6 (IL-6) in LPS-stimulated RAW264.7 macrophages without affecting cell viability. Quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR) analysis indicated that HOA also suppressed the gene expression of inducible NO synthase (iNOS), TNF-&#945;, and IL-6. Further analyses demonstrated that HOA inhibited the phosphorylation of upstream signaling molecules, including p85, PDK1, Akt, I&#954;B&#945;, ERK, and JNK, as well as the nuclear translocation of nuclear factor &#954;B (NF-&#954;B) p65. Interestingly, HOA had no effect on the LPS-induced nuclear translocation of activator protein 1 (AP-1). Taken together, these results suggest that HOA inhibits the production of cytokine by downregulating iNOS, TNF-&#945;, and IL-6 gene expression via the downregulation of phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinases (MAPKs), and the inhibition of NF-&#954;B activation. Our findings indicate that HOA could potentially be used as an anti-inflammatory agent for medical use.