Identification of differentially expressed genes in ulcerative colitis and verification in a colitis mouse model by bioinformatics analyses

BACKGROUND Ulcerative colitis(UC)is an inflammatory bowel disease that is difficult to diagnose and treat.To date,the degree of inflammation in patients with UC has mainly been determined by measuring the levels of nonspecific indicators,such as C-reactive protein and the erythrocyte sedimentation rate,but these indicators have an unsatisfactory specificity.In this study,we performed bioinformatics analysis using data from the National Center for Biotechnology Information-Gene Expression Omnibus(NCBI-GEO)databases and verified the selected core genes in a mouse model of dextran sulfate sodium(DSS)-induced colitis.AIM To identify UC-related differentially expressed genes(DEGs)using a bioinformatics analysis and verify them in vivo and to identify novel biomarkers and the underlying mechanisms of UC.METHODS Two microarray datasets from the NCBI-GEO database were used,and DEGs between patients with UC and healthy controls were analyzed using GEO2R and Venn diagrams.We annotated these genes based on their functions and signaling pathways,and then protein-protein interactions(PPIs)were identified using the Search Tool for the Retrieval of Interacting Genes.The data were further analyzed with Cytoscape software and the Molecular Complex Detection(MCODE)app.The core genes were selected and a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed.Finally,colitis model mice were established by administering DSS,and the top three core genes were verified in colitis mice using real-time polymerase chain reaction(PCR).RESULTS One hundred and seventy-seven DEGs,118 upregulated and 59 downregulated,were initially identified from the GEO2R analysis and predominantly participated in inflammation-related pathways.Seven clusters with close interactions in UC formed:Seventeen core genes were upregulated[C-X-C motif chemokine ligand 13(CXCL13),C-X-C motif chemokine receptor 2(CXCR2),CXCL9,CXCL5,C-C motif chemokine ligand 18,interleukin 1 beta,matrix metallopeptidase 9,CXCL3,formyl peptide receptor 1,complement component 3,CXCL8,CXCL1,CXCL10,CXCL2,CXCL6,CXCL11 and hydroxycarboxylic acid receptor 3]and one was downregulated[neuropeptide Y receptor Y1(NYP1R)]in the top cluster according to the PPI and MCODE analyses.These genes were substantially enriched in the cytokinecytokine receptor interaction and chemokine signaling pathways.The top three core genes(CXCL13,NYP1R,and CXCR2)were selected and verified in a mouse model of colitis using real-time PCR Increased expression was observed compared with the control mice,but only CXCR2 expression was significantly different.CONCLUSION Core DEGs identified in UC are related to inflammation and immunity inflammation,indicating that these reactions are core features of the pathogenesis of UC.CXCR2 may reflect the degree of inflammation in patients with UC.

Erlotinib inhibits progression to dysplasia in a colitis-associated colon cancer model

AIM:To investigate the role of epidermal growth factor receptor(EGFR) in colitis-associated dysplasia using the EGFR tyrosine kinase inhibitor erlotinib.METHODS:Sprague-Dawley rats received trinitrobenzene sulfonic acid(TNBS;30 mg in 50% ethanol,ic),followed 6 wk later by reactivation with TNBS(5 mg/kg,iv) for 3 d.To induce colitis-associated dysplasia,rats then received TNBS(iv) twice a week for 10 wk.One group received erlotinib(10 mg/kg,ip) for 1 wk before the start of the reactivation of the colitis and 2 wk after(21 d);the rest received the vehicle.After rats were euthanized,the colons were removed and analyzed for damage and expression of the EGFR downstream effectors Erk1/2 and c-Myc.RESULTS:Ninety percent of the vehicle-treated animals had dysplasia in any region of the colon.Erlotinib-treated animals had a significant decrease in the incidence of dysplasia compared to vehicle-treated animals in all regions of the colon(50.00% ± 11.47% vs 90.00% ± 10.00% in proximal,P < 0.05;15.00% ± 8.19% vs 50.00% ± 16.67% in mid,P < 0.05;and 20.00% ± 9.17% vs 70.00% ± 15.28% in distal,P < 0.01).Erlotinib-treated animals also had reduced cell proliferation,reduced active Erk1/2,and reduced c-Myc in colon epithelium compared with the vehicle-treated animals.In vitro,erlotinib treatment was shown to markedly decrease c-Myc and pErk1/2 levels in rat epithelial cells.Proliferation of rat epithelial cells was stimulated by epidermal growth factor and inhibited by erlotinib(P < 0.05).CONCLUSION:Erlotinib can decrease the development of colitis-associated dysplasia,suggesting a potential therapeutic use for erlotinib in patients with long-standing colitis.

Effects of electroacupuncture at lower he-sea points on interleukin-1β and high mobility group box 1 in model rats with ulcerative colitis

Objective To comparatively observe the effect of electroacupuncture at digestive system-related lower he-sea points on the expressions of serum interleukin-1β（IL-1 β）, tumor necrosis factor-α（TNF-α） of colon tissues and high mobility group box 1 protein（HMGB 1） of ulcerative colitis（UC） model rats, and to explore whether there is relative specificity of electroacupuncture at Shàngjùxū（上巨虚 ST 37）, one of lower he-sea points of large intestine, in treatment of bowel diseases. Method A total of 60 SD rats were randomly divided into control group, model group, ST 37 group, Zúsānl？（足三里 ST 36） group, Xiàjùxū（下巨虚 ST 39） group and Yánglíngquán（阳陵泉 GB 34） group. There were ten rats in each group; five were males, and five were females. UC models were established by clysis with 2, 4, 6-trinitrobenzene sulfonic acid/alcohol solution. After modeling, treatment was conducted for ten days, specimens were collected, colonic ulcers and inflammation were inspected visually and scored. The content of serum IL-1β and the expressions of TNF-α and HMGB 1 in colon were detected through ELISA. Results 1 Compared with control group, the scores of colonic ulcers and inflammation, the content of serum IL-1β and the expressions of TNF-α（except ST 37 group） and HMGB 1 were all higher（P〈0.05, P〈0.01）; 2 compared with model group, the scores of colonic ulcers in ST 36 group and ST 37 group were lower obviously（P〈0.05, P〈0.01）; the expressions of IL-1β, TNF-α and HMGB 1 in the four treatment groups were lower obviously（P〈0.01）; 3 compared with ST 37 group, the expressions of IL-1β, TNF-α and HMGB 1 in other three treatment groups were higher obviously（P〈0.05, P〈0.01）; and the scores of colonic ulcers in ST 39 group and GB 34 group were higher obviously（P〈0.05）. Conclusion 1 The score of colonic ulcers can be reduced through electroacupuncture at ST 37, ST 36, ST 39 and GB 34, which can also reduce the content of serum IL-1β and the expressions of TNF-α and HMGB 1, and effectively inhibit inflammatory response of colon caused by UC; 2 the effect trend of the four acupoints in treatment of UC is： ST 37ST 36ST 39GB 34, and electroacupuncture at ST 37 has the best effect with relative specificity.