[Pinostrobin targets the PI3K/AKT/CCL2 axis in intestinal epithelial cells to inhibit intestinal macrophage infiltration and alleviate dextran sulfate sodium-induced colitis in mice].

OBJECTIVES

To investigate the mechanism through which pinostrobin (PSB) alleviates dextran sulfate sodium (DSS)-induced colitis in mice.

METHODS

C57BL/6 mice were randomized into control group, DSS model group, and PSB intervention (30, 60, and 120 mg/kg) groups. Colitis severity of the mice was assessed by examining body weight changes, disease activity index (DAI), colon length, and histopathology. The expressions of tight junction proteins ZO-1 and claudin-1 in the colon tissues were examined using immunofluorescence staining, and macrophage infiltration and polarization were analyzed with flow cytometry. ELISA and RT-qPCR were used for detecting the expressions of inflammatory factors (TNF‑α and IL-6) and chemokines (CCL2, CXCL10, and CX3CL1) in the colon tissues, and PI3K/AKT phosphorylation levels were analyzed with Western blotting. In cultured Caco-2 and RAW264.7 cells, the effect of PSB on CCL2-mediated macrophage migration was assessed using Transwell assay. Network pharmacology analysis was performed to predict the key pathways that mediate the therapeutic effect of PSB.

RESULTS

In DSS-induced mouse models, PSB at 60 mg/kg optimally alleviated colitis, shown by reduced weight loss and DAI scores and increased colon length. PSB treatment significantly upregulated ZO-1 and claudin-1 expressions in the colon tissues, inhibited colonic macrophage infiltration, and promoted the shift of macrophage polarization from M1 to M2 type. In cultured intestinal epithelial cells, PSB significantly inhibited PI3K/AKT phosphorylation and suppressed chemokine CCL2 expression. PSB treatment obviously blocked CCL2-mediated macrophage migration of RAW264.7 cells, which could be reversed by exogenous CCL2. Network pharmacology analysis and rescue experiments confirmed PI3K/AKT and CCL2 signaling as the core targets of PSB.

CONCLUSIONS

PSB alleviates DSS-induced colitis in mice by targeting intestinal epithelial PI3K/AKT signaling, reducing CCL2 secretion, and blocking macrophage chemotaxis and migration, highlighting the potential of PSB as a novel natural compound for treatment of inflammatory bowel disease.