Chrysophanein of Rhubarb Rescues ILC3-Derived IL-22 by Blocking CCDC25/ILK/HIF-1α for Mucosal Healing in Ulcerative Colitis Mice

Ethnopharmacological relevance: In traditional Chinese medicine, rhei radix et rhizoma, is derived from the dried roots and rhizomes of Rheum palmatum L., Rheum tanguticum Maxim. ex Balf. or medicinal Rheum officinale Baill, are used to treat intestinal carbuncle and abdominal pain, as well as damp-heat dysentery. Chrysophanein is a natural compound extracted from rhei radix et rhizoma with significant anti-inflammatory properties.
Aim: Ulcerative colitis (UC) is characterized by chronic mucosal inflammation. Current therapies alleviate symptoms via anti-inflammatory effects but fail to prevent relapse. Restoring the intestinal mucosal barrier represents a novel therapeutic strategy beyond conventional approaches. This study aims to show that chrysophanein ameliorates UC symptoms by targeting the coiled-coil domain containing protein 25/integrin-linked kinase/hypoxia-inducible factor-1α(CCDC25/ILK/HIF-α) pathway to repair mucosal barrier integrity.
Methods: We established a CCDC25-overexpressing UC mouse model through the intraperitoneal injection of adeno-associated virus (AAV)-CCDC25, alongside providing the mice with free access to dextran sulfate sodium(DSS). Disease progression was evaluated through body weight, survival status, colon length, endoscopy, and histopathology. chrysophanein-treated UC mice were assessed via Alcian blue staining (mucin quantification), WB (Occludin/ZO-1/claudin-1), in vivo imaging (FITC-dextran 4000 distribution), limulus amebocyte lysate assay (serum LPS), bacterial translocation assays, WB (CCDC25/ILK/HIF-1α pathway), and flow cytometry (IL-22+ILC3s). Transmission electron microscopy (TEM) evaluated epithelial morphology, and co-culture experiments examined chrysophanein's protective effects on enterocytes.
Results: Compared to control AAV-UC mice, CCDC25-overexpressing mice exhibited exacerbated symptoms. chrysophanein significantly attenuated weight loss, hematochezia, and colon damage, enhanced mucosal barrier function (mucin, ZO-1/Occludin/Claudin-1), reduced bacterial translocation and serum LPS, suppressed CCDC25/ILK/HIF-1α, and elevated IL-22+ILC3 proportions in UC mice. However, CCDC25 overexpression diminished chrysophanein's efficacy, correlating with reduced IL-22+ILC3s. chrysophanein-MNK3-conditioned media increased TEER, lowered FD4 permeability, and upregulated ZO-1 (mimicking IL-22 recombinant protein), whereas OECCDC25-MNK3 media reversed these effects, confirming CCDC25's overexpression interferes with chrysophanein-mediated intestinal epithelial barrier repair via the IL-22 pathway.
Conclusion: Chrysophanein rescues ILC3-derived IL-22 by blocking CCDC25/ILK/HIF-1α for mucosal healing in UC.