The Study Of Matrix Gla Protein In The Pathogenesis Of Ulcerative Colitis

AIMs More and more attention was taken to the realationship of inflammatory bowel disease and vitamin D.The aim of this study was to explore the role of MGP in pathogenesis of ulcerative colitis and to investigate the upstream and downstream pathway.Material and Methods The mRNA and protein expression of MGP in colonic biopy tissues of patients with ulcerative colitis were detected by real-time PCR and immunohistochemistry.C57BL/6 mice were given DSS with different concentration(2%,2.5%,3%respectively)in drinking water for 5 days to induce experimental colitis.Weight loss,disease activity index(DAI),macroscopic and histologic colitis scores were used to evaluate the severity of colitis.The expression level of MGPmRNA and protein in colon tissues was detected by real-time PCR and western blot.We used Bioinformatics methods to predict that MGP may be regulated by early growth reaction gene-1(Egr1)and p38-MAPK-JNK pathway.The expression of Egrl,p38,p-p38,JNK,p-JNK,E-cadherin,occludin and TFF3 were detected by western blot.The effect of the transcription factor Egrl on the activity of the promoter region of MGP gene was detected by double luciferase reporter gene.Chromatin immunoprecipitation(CHIP)was chose to detect the combination of Egrl and MGP gene promoter region in DLD-1 cell line stimulated by lipopolysaccharide(LPS).Stable MGP overexpression cell lines were established in Caco-2 and DLD-1 by lentivirus transfection.The expression of E-cadherin was detected by westernblot.Results The expression of MGP mRNA in the colon biopy tissues of patients with UC(n=50)was significantly higher than that of the healthy control(n=15).MGP protein mainly located in the cytoplasm of colonic mucosal epithelial cells and goblet cells by IHC staining.Weight loss,macroscopic and histologic colitis scores increased significantly in colitis group comparing to control group(P<0.01).With the increase of DSS concentration,the inflammation of the colon in mice increased,and the expression level of MGP protein also gradually increased.The expression of Egr-1、p38、p-p38、JNK、p-JNK proteins in colon tissures were higher than that of the control group(P<0.01),while the expression of E-cadherin、occludin and TFF3 proteins decreased.Egr-1 significantly enhanced the transcriptional activity of the MGP promoter region.CHIP results showed that the combination of Egrl in MGP promoter region was significantly increased.The expression of E-cadherin protein decreased.Conclusion The expression of MGP protein in ulcerative colitis is elevated and may be regulated by transcription factor Egr-1 and p38-MAPK-JNK pathway.MGP may be involved in the pathogenesis of colon inflammation by affecting intestinal mucosal barrier.