Strictosamide ameliorates LPS-induced acute lung injury by targeting ERK2 and mediating NF-κB signaling pathway

Ethnopharmacological relevance: Acute lung injury (ALI) ranks among the deadliest pulmonary diseases, significantly impacting mortality and morbidity. Presently, the primary treatment for ALI involves supportive therapy; however, its efficacy remains unsatisfactory. Strictosamide (STR), an indole alkaloid found in the Chinese herbal medicine Nauclea officinalis (Pierre ex Pit.) Merr. & Chun (Wutan), has been found to exhibit numerous pharmacological properties, particularly anti-inflammatory effects. Aim of the study: This study aimes to systematically identify and validate the specific binding proteins targeted by STR and elucidate its anti-inflammatory mechanism in lipopolysaccharide (LPS)-induced ALI.Materials and methods: Biotin chemical modification, protein microarray analysis and network pharmacology were conducted to screen for potential STR-binding proteins. The binding affinity was assessed through surface plasmon resonance (SPR), cellular thermal shift assay (CETSA) and molecular docking, and the antiinflammatory mechanism of STR in ALI treatment was assessed through in vivo and in vitro experiments.Results: Biotin chemical modification, protein microarray and network pharmacology identified extracellularsignal-regulated kinase 2 (ERK2) as the most important binding proteins among 276 candidate STRinteracting proteins and nuclear factor-kappaB (NF-kappa B) pathway was one of the main inflammatory signal transduction pathways. Using SPR, CETSA, and molecular docking, we confirmed STR's affinity for ERK2. In vitro and in vivo experiments demonstrated that STR mitigated inflammation by targeting ERK2 to modulate the NF-kappa B signaling pathway in LPS-induced ALI. Conclusions: Our findings indicate that STR can inhibit the NF-kappa B signaling pathway to attenuate LPS-induced inflammation by targeting ERK2 and decreasing phosphorylation of ERK2, which could be a novel strategy for treating ALI.