Costunolide attenuates neuroinflammation by targeting G3BP1 and APRT

Background Costunolide (Cos) is a sesquiterpene lactone isolated from Saussurea lappa with reported anti-inflammatory properties. Its direct molecular targets in neuroinflammatory responses, however, have not been fully defined. Methods LPS-stimulated BV2 microglia were used to examine the effect of Cos on neuroinflammatory activation. Candidate binding proteins were screened using MetPro and further assessed by molecular docking. The roles of selected targets were tested by siRNA knockdown, while direct binding was examined using surface plasmon resonance (SPR). Transcriptome sequencing and qPCR were used to evaluate downstream inflammatory gene changes. Results Cos reduced LPS-induced phosphorylation of NF-κB p65, with little change in total p65 protein levels. MetPro analysis pointed to G3BP1 and APRT as potential Cos-associated proteins, and docking analysis supported possible binding of Cos to both targets. Knockdown of either G3BP1 or APRT reduced the inhibitory effect of Cos on p65 phosphorylation. SPR assays confirmed direct interaction between Cos and G3BP1/APRT. Transcriptomic analysis, together with qPCR validation, showed that Cos affected LPS-responsive inflammatory transcriptional programs. Conclusion Cos suppresses microglial inflammatory activation partly through G3BP1 and APRT, with downstream inhibition of NF-κB-related signaling. These results provide mechanistic evidence for the anti-neuroinflammatory activity of Cos and support further investigation of its therapeutic potential.