Artemisinin Alleviates Intestinal Inflammation and Metabolic Disturbance in Ulcerative Colitis Rats Induced by DSS.

Objective: This study is aimed to reveal the possible mechanisms of artemisinin in the treatment of ulcerative colitis (UC) through bioinformatics analysis and experimental verification in UC model rats. Methods: Firstly, we searched two microarray data of the Gene Expression Omnibus (GEO) database to explore the differentially expressed genes (DEGs) between UC samples and normal samples. Then, we selected DEGs for gene ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The acute UC model of rats was established by using 3.5% dextran sulfate sodium (DSS) for 10 days to verify the core pathway. Finally, we evaluated the therapeutic effect of artemisinin at the molecular level and used metabonomics to study the endogenous metabolites in the rat serum. Results: We screened in the GEO database and selected two eligible microarray datasets, GSE36807 and GSE9452. We performed GO function and KEGG pathway enrichment analyses of DEGs and found that these DEGs were mainly enriched in the inflammatory response, immune response, and IL-17 and NF-κB signaling pathways. Finally, we verified the IL-17 signaling pathway and key cytokines, and ELISA and immunohistochemical results showed that artemisinin could downregulate the expression of proinflammatory cytokines such as IL-1ß and IL-17 in the IL-17 signaling pathway and upregulate the expression of the anti-inflammatory cytokine PPAR-γ. Metabolomics analysis showed that 33 differential metabolites were identified in the artemisinin group (AG) compared to the model group (MG). Differential metabolites were mainly involved in alanine, aspartate, and glutamate metabolism and synthesis and degradation of ketone bodies. Conclusion: In this study, we found that artemisinin can significantly inhibit the inflammatory response in UC rats and regulate metabolites and related metabolic pathways. This study provides a foundation for further research on the mechanism of artemisinin in the treatment of UC.

Stigmasterol Restores the Balance of Treg/Th17 Cells by Activating the Butyrate-PPARγ Axis in Colitis.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with gut microbiota disequilibrium and regulatory T (Treg)/T helper 17 (Th17) immune imbalance. Stigmasterol, a plant-derived sterol, has shown anti-inflammatory effects. Our study aimed to identify the effects of stigmasterol on experimental colitis and the related mechanisms. Stigmasterol treatment restored the Treg/Th17 balance and altered the gut microbiota in a dextran sodium sulfate (DSS)-induced colitis model. Transplantation of the faecal microbiota of stigmasterol-treated mice significantly alleviated inflammation. Additionally, stigmasterol treatment enhanced the production of gut microbiota-derived short-chain fatty acids (SCFAs), particularly butyrate. Next, human naïve CD4+ T cells sorted from IBD patients were cultured under Treg- or Th17-polarizing conditions; butyrate supplementation increased the differentiation of Tregs and decreased Th17 cell differentiation. Mechanistically, butyrate activated peroxisome proliferator-activated receptor gamma (PPARγ) and reprogrammed energy metabolism, thereby promoting Treg differentiation and inhibiting Th17 differentiation. Our results demonstrate that butyrate-mediated PPARγ activation restores the balance of Treg/Th17 cells, and this may be a possible mechanism, by which stigmasterol attenuates IBD.

Integrin ß4 reduces DNA damage­induced p53 activation in colorectal cancer.

Integrin contributes to the maintenance of cell adhesion. In turn, cell adhesion triggers certain integrin signaling cascades, and influences cell biological behavior. In the present study, we explored the role and mechanism of integrin ß4 in the DNA damage response in colorectal cancer (CRC) using a three­dimensional (3D) cell culture model. Under 3D culture condition, dispersed CRC cells automatically formed multicellular spheroids, which consisted of layers of cells with cell junctions commonly distributed. The expression level of integrin ß4 in HCT116 3D cultures was slightly higher compared with two­dimensional (2D) cultures, while the expression level in LoVo 3D cultures was similar to or slightly lower than that in 2D cultures. Knockdown of integrin ß4 by lentiviral delivery of shRNA did not markedly change the architectural formation of 3D cultures under an inverted microscope or transmission electron microscope. Platinum increased p53 and p­p53 (ser15) in a time­dependent manner in 3D cultures. Knockdown of integrin ß4 increased sensitivity to cisplatin (CDDP) in 3D cultures. Under 3D culture condition, knockdown of integrin ß4 did not detectably change the basal p53 protein level but increased p53 and p­p53 (ser15) protein accumulation induced by platinum. Integrin ß4 knockdown did not detectably change p53 protein level in HCT116 2D cultures with or without CDDP treatment. Knockdown of wild­type p53 decreased sensitivity to platinum in 3D cultures. Since it has been proven that platinum damages DNA to kill cells and p53 plays a key role in the DNA damage response, our results indicated that integrin ß4 reduced DNA damage­induced p53 activation to decrease chemosensitivity in CRC. This may be due to integrin ß4 activation in 3D cultures.