摘要
Background and aims:Crohn’s disease(CD)and intestinal tuberculosis(ITB)are both chronic granulomatous conditions with similar phenotypic presentations.Hence,there is need for a biomarker to differentiate between both these two diseases.This study aimed at genome-wide gene expression analysis of colonic biopsies from confirmed cases of ITB and CD in comparison with controls.To evaluate the role of T regulatory cells,forkhead box P3(FOXP3)mRNA expression was quantified in serum as well as in colonic biopsies from patients with ITB and with the controls.Methods:Paired samples,including serum and colonic biopsies,were taken from 33 study subjects(CD,ITB and controls),and total RNA was extracted.Human whole genome gene expression microarray analysis was performed using the Illumina HumanWG-6 BeadChip Kit with six total RNA samples of the three groups in duplicates.Real-time PCR for FOXP3 mRNA expression was analyzed in serum samples and colonic biopsy samples(4-CD,5-ITB,4-controls).Results:In CD and ITB there was 1.5-fold upregulation of 92 and 382 genes and 1.5-fold downregulation of 91 and 256 genes,respectively.Peroxisome proliferators via the PPARc pathway were most significantly downregulated(P<0.005)in CD.Additionally,the IL4/5/6 signaling pathways and Toll-like receptor signaling pathway were identified as significantly differentially regulated(P<0.005)at>2-fold change.In ITB,the complement activation pathway,specifically the classical pathway,was the most significantly upregulated.FOXP3 mRNA expression was significantly elevated in colonic biopsies obtained from ITB patients as compared with CD cases(4.7062.21 vs 1.4860.31,P=0.016).Conclusions:FOXP3 mRNA expression in colonic mucosa could be a discriminatory marker between ITB and CD.Upregulation of the complement activation pathway in ITB suggests that pathogenetic mechanisms for ITB are similar to those of pulmonary tuberculosis.In CD,downregulation of PPARc was seen in colonic tissue,suggesting that restoration of PPARc-dependent anti-microbial barrier function may be a therapeutic target.
背景:克罗恩病(CD)和肠结核(ITB)是有着相似表型的慢性肉芽肿性疾病,因此,找到一种生物标志物来鉴别这两种疾病是必要的。本研究旨在对ITB和CD的结肠标本进行全基因表达分析。同时,为了评价调节性T细胞的作用,我们对血清标本及结肠标本进行FOXP3 mRNA定量检测。方法:收集33名研究对象(CD患者、ITB患者及正常对照)血清和结肠组织配对样本,提取标本中的总RNA。采用Illumina HumanWG-6 BeadChip试剂盒对3组研究对象中的6种总RNA样本进行人类全基因组表达芯片分析。采用real-time PCR对具有合格RNA样本的病例(CD 4例,ITB 5例,正常对照4例)血清和组织标本进行FOXP3 mRNA表达水平检测。结果:在CD和ITB患者中,分别有92和382个基因表达上调1.5倍,91和256个基因表达下调1.5倍。过氧化物酶体增殖物介导的PPARγ信号通路在CD中下调最为显著(P<0.005);此外,IL4/5/6信号通路和Toll样受体信号通路也存在显著差异表达,上调2倍以上。而在ITB患者上调最为显著是补体活化通路尤其是经典通路。ITB患者结肠组织标本中FOXP3 mRNA表达水平明显高于CD患者(4.7062.21 vs 1.4860.31,P=0.016)。结论:结肠黏膜FOXP3 mRNA表达可作为鉴别ITB与CD的一项标志物。ITB患者补体激活通路的上调提示ITB的发病机制与肺结核相似。CD患者中PPARγ通路的下调提示PPARγ依赖的微生物屏障功能可能成为新的治疗靶点。
基金
This project was undertaken under the‘FIST’scheme of Department of Science and Technology,Government of India.In addition,support was taken from ICMR Senior Research Fellowship granted to VM.
