Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn's disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P<0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD.

• Klíčová slova
• DNA methylation, DNA methylome, Pediatric inflammatory bowel disease, epigenetics, expression, treatment naïve, ulcerative colitis,
• MeSH
• Crohnova nemoc genetika   imunologie   MeSH
• dítě MeSH
• epigeneze genetická MeSH
• exprese genu MeSH
• kolon imunologie   MeSH
• lidé MeSH
• metylace DNA imunologie   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• předškolní dítě MeSH
• slizniční imunita MeSH
• střevní sliznice imunologie   MeSH
• studie případů a kontrol MeSH
• ulcerózní kolitida genetika   imunologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Altered expression and methylation pattern of tumor suppressor and DNA repair genes, in particular involved in mismatch repair (MMR) pathway, frequently occur in primary colorectal (CRC) tumors. However, little is known about (epi)genetic changes of these genes in precancerous and early stages of CRC. The aim of this pilot study was to analyze expression profile and promoter methylation status of important tumor suppressor and DNA repair genes in the early stages of experimentally induced colorectal carcinogenesis. Rats were treated with azoxymethane (AOM), dextran sodium sulphate (DSS) or with their combination, and sacrificed 1 or 4 months post-treatment period. The down-regulation of Apc expression in left colon, detectable in animals treated with DSS-AOM and sacrificed 1 month after the end of treatment, represents most early marker of the experimental colorectal carcinogenesis. Significantly reduced gene expressions were also found in 5 out of 7 studied MMR genes (Mlh1, Mlh3, Msh3 Pms1, Pms2), regarding the sequential administration of DSS-AOM at 4 months since the treatment. Strong down-regulation was also discovered for Apc, Apex1, Mgmt and TP53. Tumors developed in rectum-sigmoid region displayed significantly lower Apc and Pms2 expressions. The decreased expression of studied genes was not in any case associated with aberrant methylation of promoter region. Present data suggest that down-regulation of Apc and MMR genes are prerequisite for the development of CRC. In this study we addressed for the first time early functional alterations of tumor suppressor genes with underlying epigenetic mechanisms in experimentally induced CRC in rats.

• MeSH
• kolon metabolismus   patologie   MeSH
• krysa rodu Rattus MeSH
• metylace DNA genetika   MeSH
• nádorové supresorové proteiny genetika   metabolismus   MeSH
• nádory tračníku genetika   MeSH
• pilotní projekty MeSH
• polymerázová řetězová reakce MeSH
• potkani Wistar MeSH
• regulace genové exprese u nádorů * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorové supresorové proteiny MeSH

BACKGROUND: Changes in the methylation status of inflammatory bowel disease (IBD)-associated genes could significantly alter levels of gene expression, thereby contributing to disease onset and progression. We previously identified seven disease-associated DNA methylation loci from intestinal tissues of IBD patients using the Illumina GoldenGate BeadArray assay. AIMS: In this study, we extended this approach to identify IBD-associated changes in DNA methylation in B cells from 18 IBD patients [9 Crohn's disease (CD) and 9 ulcerative colitis (UC)]. B cell DNA methylation markers are particularly favorable for diagnosis due to the convenient access to peripheral blood. METHODS: We examined DNA methylation profiles of B cell lines using the Illumina GoldenGate BeadArray assay. Disease-associated CpGs/genes with changes in DNA methylation were identified by comparison of methylation profiles between B cell lines from IBD patients and their siblings without IBD. BeadArray data were validated using a bisulfite polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) method. To verify that observed changes in DNA methylation were not due to virus transformation, we compared specific CpG DNA methylation levels of GADD45A and POMC between B cell lines and matching peripheral blood B lymphocytes from five individuals. RESULTS: Using this approach with strict statistical analysis, we identified 11 IBD-associated CpG sites, 14 CD-specific CpG sites, and 24 UC-specific CpG sites with methylation changes in B cells. CONCLUSIONS: IBD- and subtype-specific changes in DNA methylation were identified in B cells from IBD patients. Many of these genes have important immune and inflammatory response functions including several loci within the interleukin (IL)-12/IL-23 pathway.

• MeSH
• B-lymfocyty fyziologie   MeSH
• buněčné linie MeSH
• Crohnova nemoc metabolismus   MeSH
• dospělí MeSH
• interleukin-2 genetika   metabolismus   MeSH
• interleukin-23 - podjednotka p19 genetika   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metylace DNA fyziologie   MeSH
• regulace genové exprese fyziologie   MeSH
• ulcerózní kolitida metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Il23a protein, mouse MeSH Prohlížeč
• interleukin-2 MeSH
• interleukin-23 - podjednotka p19 MeSH