Résumé
Toll-like receptors (TLRs) family may play important roles in inflammatory bowel disease. This study examined the expression of TLR2, TLR4 and TLR9 in the colonic tissues of patients with ulcerative colitis (UC) and explored their roles in the pathogenesis of UC. Colonic biopsies were taken from the colon of 30 patients with mild or moderate UC (at active phase) and 10 healthy controls during colonoscopy. TLR2, TLR4 and TLR9 protein expression levels were immunohistochemically detected. The mRNA expression levels of TLR2, TLR4 and TLR9 were assessed by reverse transcription polymerase chain reaction (RT-PCR). The disease activity index (DAI), colonoscopic and histologic grades and fecal microbial flora were determined. Histological examination showed that the intestinal mucous membrane of UC patients underwent acute inflammation changes. Immunohistochemistry exhibited that the expression levels of TLR2, TLR4 and TLR9 in colon epithelia and inflammatory cells were higher in UC patients than in control group (P<0.01). The mRNA expression levels of TLR2, TLR4 and TLR9 were increased in UC patients but were not detected in the normal controls. Expression levels of TLR2, TLR4 and TLR9 were positively correlated, and bore close correlation with DAI, colonoscopic and histologic grades and fecal microbial flora. An important mechanism of UC might be that abnormal activation of mucosal immunity by intestinal dysbacteriosis caused dysregulation of TLRS that mediates innate immunity.
Résumé
Toll-like receptors (TLRs) family may play important roles in inflammatory bowel disease. This study examined the expression of TLR2, TLR4 and TLR9 in the colonic tissues of patients with ulcerative colitis (UC) and explored their roles in the pathogenesis of UC. Colonic biopsies were taken from the colon of 30 patients with mild or moderate UC (at active phase) and 10 healthy controls during colonoscopy. TLR2, TLR4 and TLR9 protein expression levels were immunohistochemically detected. The mRNA expression levels of TLR2, TLR4 and TLR9 were assessed by reverse transcription polymerase chain reaction (RT-PCR). The disease activity index (DAI), colonoscopic and histologic grades and fecal microbial flora were determined. Histological examination showed that the intestinal mucous membrane of UC patients underwent acute inflammation changes. Immunohistochemistry exhibited that the expression levels of TLR2, TLR4 and TLR9 in colon epithelia and inflammatory cells were higher in UC patients than in control group (P<0.01). The mRNA expression levels of TLR2, TLR4 and TLR9 were increased in UC patients but were not detected in the normal controls. Expression levels of TLR2, TLR4 and TLR9 were positively correlated, and bore close correlation with DAI, colonoscopic and histologic grades and fecal microbial flora. An important mechanism of UC might be that abnormal activation of mucosal immunity by intestinal dysbacteriosis caused dysregulation of TLRS that mediates innate immunity.
Sujets)
Femelle , Humains , Mâle , Rectocolite hémorragique , Génétique , Métabolisme , Anatomopathologie , Côlon , Métabolisme , Microbiologie , Coloscopie , Fèces , Microbiologie , Expression des gènes , Immunohistochimie , Muqueuse intestinale , Métabolisme , Microbiologie , RT-PCR , Indice de gravité de la maladie , Récepteur de type Toll-2 , Génétique , Récepteur de type Toll-4 , Génétique , Récepteur-9 de type Toll-like , GénétiqueRésumé
<p><b>OBJECTIVE</b>To investigate the effect of (AT)n repeat polymorphism of the 3'untranslated region in cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene on CTLA-4 mRNA stability and full length (flCTLA-4) and soluble CTLA4 (sCTLA-4) expression in ulcerative colitis (UC).</p><p><b>METHODS</b>flCTLA-4 mRNA in colonic biopsies and sCTLA-4 mRNA stability in peripheral blood mononuclear cells of UC patients were measured by quantitative PCR and half-life, respectively. The protein expression of flCTLA-4 in colonic biopsies and sCTLA-4 in sera of UC patients were determined by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The polymorphism of CTLA-4 (AT)n repeats in 300 UC and 700 age and sex matched healthy controls was genotyped by fluorescent PCR.</p><p><b>RESULTS</b>Among the UC patients, sCTLA-4 mRNA expression levels were decreased in active disease compared to non-active disease (P= 0.004). Carriers of the longer alleles of the (AT)n repeats expressed lower levels of flCTLA-4 and sCTLA-4 mRNA and sCTLA-4 protein than those of the shorter alleles in UC (all P< 0.01), and mRNA with long (AT)n repeat alleles has shorter half-life than mRNA with short alleles and, hence, are unstable. The frequency of long allele carriers of CTLA-4 (AT)n repeats was significantly higher in UC patients than in the healthy controls (22.0% vs. 6.3%, P< 0.01, OR= 4.21, 95% CI: 2.79-6.33), and associated with extensive colitis (P= 0.008).</p><p><b>CONCLUSION</b>CTLA-4 gene expression levels were associated with (AT)n repeat polymorphisms in UC patients. The expression of CTLA-4 mRNA and protein were decreased in carriers of the longer alleles of the (AT)n repeats of CTLA-4 gene. This study suggests that CTLA-4 plays an important role in genetic risk and pathophysiology for UC in central China.</p>
Sujets)
Adulte , Femelle , Humains , Mâle , Antigènes CD , Chimie , Génétique , Métabolisme , Antigène CTLA-4 , Études cas-témoins , Rectocolite hémorragique , Génétique , Métabolisme , Régulation de l'expression des gènes , Génotype , Phénotype , Polymorphisme génétique , Stabilité de l'ARN , Génétique , ARN messager , Chimie , Génétique , Métabolisme , SolubilitéRésumé
Objective To determine the level of defensins(HNP_(1-3))and interleukin-8(IL-8)in colon tissue of patients with ulcerative colitis(UC)and to explore the relationship between HNP_(1-3)and IL-8 and the severity of disease.Methods The level of HNP_(1-3)and IL-8 in colon mucosa of UC patients was detected by immunohistochemistry method.Results The levels of HNP_(1-3)and IL-8 in colon mucosa of UC patients were much higher than that of normal controls.The expression of HNP_(1-3)and IL 8 of UC patients was higher in involved mueosa than in corresponding normal mucosa.The expression of HNP_(1-3) and IL-8 was related to the extent of lesion and the degree of disease.The expression of HNP_(1-3)was significantly correlated with that of IL-8(r_s＝0.957,P＜0.01).Conclusions The induction of HNP_(1-3) and IL-8 was involved in process of inflammation and development of UC.Regulating mechanisms of HNP_(1-3)expression might be related with the induction of IL-8.