Corylin inhibits LPS-induced inflammatory response and attenuates the activation of NLRP3 inflammasome in microglia

Abstract

Abstract Background Inflammation has been found to be associated with many neurodegenerative diseases, including Parkinson’s and dementia. Attenuation of microglia-induced inflammation is a strategy that impedes the progression of neurodegenerative diseases. Methods We used lipopolysaccharide (LPS) to simulate murine microglia cells (BV2 cells) as an experimental model to mimic the inflammatory environment in the brain. In addition, we examined the anti-inflammatory ability of corylin, a main compound isolated from Psoralea corylifolia L. that is commonly used in Chinese herbal medicine. The production of nitric oxide (NO) by LPS-activated BV2 cells was measured using Griess reaction. The secretion of proinflammatory cytokines including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) by LPS-activated BV2 cells was analyzed using enzyme-linked immunosorbent assay (ELISA). The expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase-activation and recruitment domain (ASC), caspase-1, IL-1β and mitogen-activated protein kinases (MAPKs) in LPS-activated BV2 cells was examined by Western blot. Results Our experimental results demonstrated that corylin suppressed the production of NO and proinflammatory cytokines by LPS-activated BV2 cells. In addition, corylin inhibited the expression of iNOS and COX-2, attenuated the phosphorylation of ERK, JNK and p38, decreased the expression of NLRP3 and ASC, and repressed the activation of caspase-1 and IL-1β by LPS-activated BV2 cells. Conclusion Our results indicate the anti-inflammatory effects of corylin acted through attenuating LPS-induced inflammation and inhibiting the activation of NLRP3 inflammasome in LPS-activated BV2 cells. These results suggest that corylin might have potential in treating brain inflammation and attenuating the progression of neurodegeneration diseases.

Keywords

• Microglia
• Corylin
• MAPK signaling pathway
• NLRP3 inflammasome
• Anti-inflammation