Scutellarin attenuates intestinal epithelial cells pyroptosis in colitis by suppressing P2RX7/NLRP3 signaling pathway

Intestinal epithelial pyroptosis drives intestinal mucosal injury in colitis. Scutellarin, a natural flavonoid, has been reported to exert anti-colitis activity. However, the mechanism by which scutellarin reverses pyroptosis in intestinal epithelial cells remains elusive.

In LPS + ATP-induced NCM460 cells, scutellarin attenuated purinergic 2X7 receptor (P2RX7) expression and NOD-like receptor family pyrin domain-containing 3 (NLRP3)-mediated pyroptosis. Moreover, scutellarin suppressed K+ efflux and reactive oxygen species (ROS) generation. Scutellarin disrupted the assembly and activation of the NLRP3 inflammasome by blocking the interaction of NLRP3 with apoptosis-associated speck-like protein (ASC) and with NEK7, and by suppressing ASC oligomerization and speck formation. Molecular docking, surface plasmon resonance, and cellular thermal shift assays collectively verified the binding affinity of scutellarin to P2RX7. P2RX7 knockdown experiments further confirmed that the effect of scutellarin on K+ efflux, ROS, and pyroptosis was dependent on P2RX7 regulation. In the dextran sulfate sodium salt-induced colitis model, scutellarin significantly attenuated colitis symptoms, inflammatory responses, and intestinal barrier damage. Scutellarin significantly inhibited the expression of NLRP3, cleaved caspase-1/caspase-1, ASC, and GSDMD-N/Gasdermin D (GSDMD) in the colon. Scutellarin reduced the expression of GSDMD-N in the colonic intestinal epithelial cells (IECs).

This study demonstrates that scutellarin may ameliorate colitis by suppressing pyroptosis in IECs via the P2RX7/NLRP3 pathway, offering novel insights into its therapeutic mechanism against colitis.