Oridonin ameliorates ulcerative colitis by activating autophagy via PI3K/AKT/mTOR pathway inhibition

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent inflammation of the colon, leading to symptoms like abdominal pain, diarrhea, and weight loss. Current treatments often involve immunosuppressants or biologics, which can have significant side effects and may not be effective for all patients. A key pathological mechanism in UC involves dysregulated inflammatory responses and impaired cellular homeostasis, including autophagy. The PI3K/AKT/mTOR signaling pathway is a critical regulator of cell growth, survival, and autophagy, making it a promising target for therapeutic intervention in inflammatory conditions like UC.

Researchers investigated Oridonin's effects in an LPS-induced macrophage inflammatory model in vitro and a dextran sulfate sodium (DSS)-induced mouse UC model in vivo. In vitro, appropriate drug concentrations were determined via Cell Counting Kit-8 assay. Protein and mRNA expression of signaling pathways, autophagy, and inflammatory cytokines were assessed using Western blotting and reverse transcription-quantitative polymerase PCR. The autophagy inhibitor 3-methyladenine was used to confirm the PI3K/AKT/mTOR pathway's role. In vivo, disease activity index (DAI) was recorded, colon tissue damage was assessed by hematoxylin and eosin staining, and serum inflammatory cytokines were measured via ELISA. Network pharmacology and enrichment analyses predicted the PI3K/AKT/mTOR pathway's involvement, validated by immunohistochemistry, immunofluorescence, and Western blotting of colon tissues.

Oridonin demonstrated significant anti-inflammatory effects in both in vitro and in vivo models. In LPS-stimulated macrophages, Oridonin significantly reduced the expression of pro-inflammatory cytokines and increased the anti-inflammatory cytokine interleukin-10. In the DSS-induced colitis mouse model, Oridonin treatment alleviated body weight loss, decreased DAI scores, and improved colon shortening. It also upregulated the expression of intestinal tight junction proteins, crucial for gut barrier integrity. Mechanistically, Oridonin inhibited the PI3K/AKT/mTOR pathway, which was evidenced by altered autophagy-related molecular markers. Specifically, it increased levels of autophagy-related proteins ATG13, beclin-1, ATG12, ATG7, and ATG5, while decreasing the expression of p62.