Taraxasterol Inhibits LPS-Induced Inflammatory Response in BV2 Microglia Cells by Activating LXRα

Abstract

Neuroinflammation plays a critical role in the development of neurodegenerative diseases. Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been reported to have anti-inflammatory effect. The aim of this study was to investigate the anti-inflammatory effects and mechanism of taraxasterol in LPS-stimulated BV2 microglia cells. BV2 microglia cells were treated with taraxasterol 12 h before LPS stimulation. The effects of taraxasterol on LPS-induced TNF-α and IL-1β production were detected by ELISA. The effects of taraxasterol on LXRα, ABCA1, TLR4, and NF-κB expression were detected by western blot analysis. The results showed that taraxasterol dose-dependently inhibited LPS-induced TNF-α and IL-1β production and NF-κB activation. Taraxasterol also disrupted the formation of lipid rafts and inhibited translocation of TLR4 into lipid rafts. Furthermore, taraxasterol was found to activate LXRα-ABCA1 signaling pathway which induces cholesterol efflux from cells. In addition, our results showed that the anti-inflammatory effect of taraxasterol was attenuated by transfection with LXRα siRNA. In conclusion, these results suggested that taraxasterol inhibits LPS-induced inflammatory response in BV2 microglia cells by activating LXRα-ABCA1 signaling pathway.

Lipid rafts in glial cells: role in neuroinflammation and pain processing

“…Microglia from mice deficient in ABCA1 exhibit augmented LPS- (108). Anti-inflammatory effects of taraxasterol, a pentacyclic-triterpene isolated from dandelion (Taraxacum officinale), in LPS--ABCA1 signaling pathway, which induces cholesterol efflux, and disruption of lipid rafts (109). Similarly, platycodin D, a triterpenesaponin extracted from Chinese bellflower (Platycodon grandiflorum) and also known to have anti-inflammatory effects, inhibits LPS-induced ROS, TNF--6, and IL-microglia cells.…”

Phenolic Fractions from Dandelion Leaves and Petals as Modulators of the Antioxidant Status and Lipid Profile in an In Vivo Study

“…This is due to a wide range of biological activities, including antihyperglycemic, antioxidant and anti-inflammatory actions demonstrated by dandelion fractions and their constituents, with no reported adverse effects, together with a well-understood chemical composition and a widespread occurrence of the plant throughout the world [10,11]. Aqueous-organic extracts from the dandelion herb were found to exert an anti-inflammatory action [12], mainly due to decreasing the expression of proinflammatory cytokines by inhibiting the nuclear factor (NF)-κB [13], tumor necrosis factor (TNF)-α and interleukin (IL)-1β [14], as well as reducing the expression and production of inducible nitric oxide synthase/nitric oxide (iNOS/NO) and cyclooxygenase (COX)-2/prostaglandin E2 [15].Plant polyphenols have the ability to protect dietary lipids, proteins and vitamins from oxidation. Additionally, they may also provide health benefits associated with preventing damage to the building elements of the body (DNA, lipids and proteins) due to decreased biological degeneration [16][17][18].…”

Microglial Cell Morphology and Phagocytic Activity Are Critically Regulated by the Neurosteroid Allopregnanolone: A Possible Role in Neuroprotection

“…Both of the isoforms are expressed by CD4 + T cells and macrophages, where their activation reduces proinflammatory cytokine expression [ 73 , 74 ]. In BV-2 cells, the expression of LXR α has been associated to the anti-inflammatory activity of taraxasterol [ 75 ]. PXR is expressed in monocyte/macrophage cells, where they participate in an anti-inflammatory pathway [ 76 ].…”