Ligustilide Suppresses Macrophage-Mediated Intestinal Inflammation and Restores Gut Barrier via EGR1-ADAM17-TNF-α Pathway in Colitis Mice

Ulcerative colitis is a chronic nonspecific intestinal inflammatory disease, which usually occurs in the rectal and colonic mucosa and submucosa. Ligustilide, a major component derived from Angelica sinensis (Oliv.) Diels, exerts anti-inflammation effect. However, its impact and molecular mechanism on colitis remain obscure. In this study, in vivo and in vitro experiments verified that ligustilide protected against colitis by suppressing macrophage-mediated inflammation and repairing intestinal barrier. Of note, we utilized a thermal proteome profiling strategy to preliminarily find early growth response factor 1 (EGR1) as a target of ligustilide. Cellular thermal shift assay, drug affinity responsive target stability, and surface plasmon resonance analysis revealed that ligustilide directly targeted His386 to bind to EGR1. Furthermore, RNA-sequencing, dual luciferase reporter gene assay, and rescue experiments illustrated that ligustilide disturbed the nuclear translocation of EGR1 and broke its combination with a disintegrin and metalloproteinase 17 (ADAM17) promoter, thereby inhibiting ADAM17 transcription and downstream tumor necrosis factor-α (TNF-α) production, as well as expression of inflammatory proteins cyclooxygenase 2 and inducible nitric oxide synthase. Finally, the in vivo experiment with EGR1 overexpression proved that EGR1 was essential for the protective effects of ligustilide on colitis mice. Taken together, our study demonstrates that ligustilide targets EGR1 to inhibit the EGR1-ADAM17-TNFα pathway, thus alleviating macrophage-mediated intestinal inflammation and restoring gut barrier.