Luteolin ameliorates DSS-induced colitis in mice via suppressing macrophage activation and chemotaxis

Abstract

Objectives: Luteolin, known for its multifaceted therapeutic properties against inflammatory diseases, holds potential for addressing the unmet need for effective treatments in ulcerative colitis (UC), a prevalent subtype of inflammatory bowel disease (IBD). This study aimed to comprehensively assess luteolin's therapeutic efficacy in a dextran sulfate sodium (DSS)-induced colitis mouse model, shedding light on its anti-UC mechanisms.

Methods: Our investigation encompassed in vivo assessments of luteolin's therapeutic potential against DSS-induced colitis through rigorous histopathological examination and biochemical analyses. Furthermore, we scrutinized luteolin's anti-inflammatory prowess in vitro using lipopolysaccharide (LPS)-stimulated RAW264.7 cells and primary peritoneal macrophages. Additionally, we quantitatively evaluated the impact of luteolin on C-C motif chemokine ligand 2 (CCL2)-induced macrophage migration employing Transwell and Zigmond chambers. Furthermore, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) assay, and molecular docking were employed to identify potential therapeutic targets of luteolin and investigate their binding sites and interaction patterns.

Results: Luteolin demonstrated therapeutic potential against DSS-induced colitis by ameliorating colitis symptoms, restoring intestinal barrier integrity, and inhibiting proinflammatory cytokine production in the colonic tissues. Moreover, luteolin demonstrated robust anti-inflammatory activity in vitro, in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and primary peritoneal macrophages. Notably, luteolin suppressed the phosphorylation of IKKα/β, IκBα, and p65, along with preventing IκBα degradation in LPS-treated RAW264.7 cells and peritoneal macrophages. Furthermore, luteolin impaired the migratory behavior of RAW264.7 cells and peritoneal macrophages, as evidenced by reduced migration distance and velocity of luteolin-treated macrophages. Mechanistically, luteolin was found to antagonize IKKα/β, subsequently inhibiting IKKα/β phosphorylation and the activation of NF-κB signaling.

Conclusion: Luteolin emerges as a promising lead compound for the clinical therapy of colitis by virtue of its ability to ameliorate DSS-induced colitis, antagonize IKKα/β, suppress NF-κB signaling, and impede macrophage activation and migration.

Keywords: Chemotaxis; Colitis; Inflammation; Luteolin; Macrophage.