Modified Jiaoqi Powder enhances epithelial autophagy against TNF-triggered apoptosis in chronic ulcerative colitis

Background: A vicious cycle of dysregulated intestinal epithelial cell death, intestinal barrier defect, and subsequent inflammation response is core to chronic ulcerative colitis (UC). Modified Jiaoqi Powder (MJQP), a traditional Chinese medicine formula, has been clinically applied to treat chronic relapsing and chronic persistent types of UC. Nevertheless, the underlying mechanisms of MJQP in chronic UC remains unknown.

Purpose: The present study aimed to demonstrate the favorable effects and potential molecular mechanisms of MJQP in chronic UC.

Methods: The chemical components of MJQP and MJQP drug serum were identified by LC-MS/MS. The curative effects of MJQP were evaluated in a well-established DSS-induced chronic UC mice model by measuring body weight, colon length, disease activity index (DAI) and histological scores. Serum cytokines, including interleukin (IL)-1β, IL-12, IL-13, IL-4, tumor necrosis factor-alpha (TNF-α), and IFN-γ were measured using enzyme-linked immunosorbent assay. Western blotting, immunofluorescence, and MTT assay were used to analyze the effects of MJQP on colonic barrier function in chronic UC mice and human epithelial cell lines. TUNEL assay, western blotting, and flow cytometry were used to examine the related apoptosis indicators. An electron microscope was used to observe autophagosomes and autolysosomes, while western blotting and immunofluorescence were used to detect autophagy-associated proteins. Network pharmacology was used to predict potential targets and pathways of MJQP in UC. Finally, the TNF pathway-related proteins were detected by immunohistochemistry and western blotting.

Results: MJQP administration prevented the UC progression, as evidenced by faster weight gain, longer colon length, lower histological scores and DAI, and up-/down- regulation of inflammatory factors. The expression of tight junction proteins, ki67, and E-cadherin increased dose-dependently after MJQP intervention. Moreover, MJQP treatment promoted the viability of NCM460 and Caco2 cells in a concentration-dependent manner. MJQP dose-dependently decreased the proportion of TUNEL-positive cells and attenuated the pro-apoptotic proteins cleaved-caspase 8 and cleaved-caspase 3 in colonic tissues. Flow cytometry also showed that MJQP dose-dependently decreased the apoptotic cell population of LPS-induced NCM460 and Caco2 cells. Electron microscopy revealed that autophagosomes and autolysosomes were significantly improved in the MJQP-treated groups. Additionally, autophagy-related proteins were significantly expressed after MJQP treatment. Network pharmacological analysis predicted that MJQP may alleviate chronic UC by promoting intestinal epithelial cell proliferation and affecting TNF-related signaling pathways. As anticipated, the TNF pathway-associated proteins were attenuated dose-dependently in colonic tissues after MJQP treatment.

Conclusion: These results provide novel therapeutic strategies indicating that MJQP may be a promising candidate treatment for chronic UC by promoting epithelial barrier restitution by enhancing epithelial autophagy against TNF-mediated apoptosis.