Calenduloside E inhibits lipopolysaccharide-induced inflammatory response by inhibiting activation of ROS-mediated JAK1-stat3 signaling pathway in RAW264.7 cells / 南方医科大学学报

ABSTRACT

OBJECTIVE@#To investigate the effect of calenduloside E on lipopolysaccharide (LPS)-induced inflammatory response in RAW264.7 cells and explore the underlying molecular mechanism.@*METHODS@#CCK-8 assay was used to examine the effect of different concentrations of calenduloside E (0-30 μg/mL) on the viability of RAW264.7 cells. The release of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in RAW264.7 cells in response to pretreatment with 6, 8, and 10 μg/mL calenduloside E for 2 h followed by stimulation with 100 ng/mL LPS was detected using enzyme-linked immunosorbent assay (ELISA). The expression levels of iNOS and COX-2 and the activation of JAK-stats, MAPKs and NF-кB signaling pathways in the treated cells were determined using Western blotting. A reactive oxygen species (ROS) detection kit was used to detect ROS production in the cells, and the nuclear translocation of the transcription factor stat3 was observed by laser confocal microscopy.@*RESULTS@#Calenduloside E below 20 μg/mL did not significantly affect the viability of RAW264.7 cells. Calenduloside E dose-dependently decreased the expression levels of iNOS and COX-2 induced by LPS, inhibited LPS-induced release of TNF-α and IL-1β, and suppressed LPS-induced JAK1-stat3 signaling pathway activation and stat3 nuclear translocation. Calenduloside E also significantly reduced ROS production induced by LPS in RAW264.7 cells.@*CONCLUSIONS@#Calenduloside E inhibits LPS-induced inflammatory response by blocking ROS-mediated activation of JAK1-stat3 signaling pathway in RAW264.7 cells.