OBJECTIVES: Epigenetics can influence disease susceptibility and severity. While DNA methylation of individual genes has been explored in autoimmunity, no unbiased systematic analyses have been reported. Therefore, a genome-wide evaluation of DNA methylation loci in fibroblast-like synoviocytes (FLS) isolated from the site of disease in rheumatoid arthritis (RA) was performed. METHODS: Genomic DNA was isolated from six RA and five osteoarthritis (OA) FLS lines and evaluated using the Illumina HumanMethylation450 chip. Cluster analysis of data was performed and corrected using Benjamini-Hochberg adjustment for multiple comparisons. Methylation was confirmed by pyrosequencing and gene expression was determined by qPCR. Pathway analysis was performed using the Kyoto Encyclopedia of Genes and Genomes. RESULTS: RA and control FLS segregated based on DNA methylation, with 1859 differentially methylated loci. Hypomethylated loci were identified in key genes relevant to RA, such as CHI3L1, CASP1, STAT3, MAP3K5, MEFV and WISP3. Hypermethylation was also observed, including TGFBR2 and FOXO1. Hypomethylation of individual genes was associated with increased gene expression. Grouped analysis identified 207 hypermethylated or hypomethylated genes with multiple differentially methylated loci, including COL1A1, MEFV and TNF. Hypomethylation was increased in multiple pathways related to cell migration, including focal adhesion, cell adhesion, transendothelial migration and extracellular matrix interactions. Confirmatory studies with OA and normal FLS also demonstrated segregation of RA from control FLS based on methylation pattern. CONCLUSIONS: Differentially methylated genes could alter FLS gene expression and contribute to the pathogenesis of RA. DNA methylation of critical genes suggests that RA FLS are imprinted and implicate epigenetic contributions to inflammatory arthritis.
OBJECTIVES: Epigenetics can influence disease susceptibility and severity. While DNA methylation of individual genes has been explored in autoimmunity, no unbiased systematic analyses have been reported. Therefore, a genome-wide evaluation of DNA methylation loci in fibroblast-like synoviocytes (FLS) isolated from the site of disease in rheumatoid arthritis (RA) was performed. METHODS: Genomic DNA was isolated from six RA and five osteoarthritis (OA) FLS lines and evaluated using the Illumina HumanMethylation450 chip. Cluster analysis of data was performed and corrected using Benjamini-Hochberg adjustment for multiple comparisons. Methylation was confirmed by pyrosequencing and gene expression was determined by qPCR. Pathway analysis was performed using the Kyoto Encyclopedia of Genes and Genomes. RESULTS: RA and control FLS segregated based on DNA methylation, with 1859 differentially methylated loci. Hypomethylated loci were identified in key genes relevant to RA, such as CHI3L1, CASP1, STAT3, MAP3K5, MEFV and WISP3. Hypermethylation was also observed, including TGFBR2 and FOXO1. Hypomethylation of individual genes was associated with increased gene expression. Grouped analysis identified 207 hypermethylated or hypomethylated genes with multiple differentially methylated loci, including COL1A1, MEFV and TNF. Hypomethylation was increased in multiple pathways related to cell migration, including focal adhesion, cell adhesion, transendothelial migration and extracellular matrix interactions. Confirmatory studies with OA and normal FLS also demonstrated segregation of RA from control FLS based on methylation pattern. CONCLUSIONS: Differentially methylated genes could alter FLS gene expression and contribute to the pathogenesis of RA. DNA methylation of critical genes suggests that RA FLS are imprinted and implicate epigenetic contributions to inflammatory arthritis.
Authors: David M Lee; Hans P Kiener; Sandeep K Agarwal; Erika H Noss; Gerald F M Watts; Osamu Chisaka; Masatoshi Takeichi; Michael B Brenner Journal: Science Date: 2007-01-25 Impact factor: 47.728
Authors: John W Hollingsworth; Shuichiro Maruoka; Kathy Boon; Stavros Garantziotis; Zhuowei Li; John Tomfohr; Nathaniel Bailey; Erin N Potts; Gregory Whitehead; David M Brass; David A Schwartz Journal: J Clin Invest Date: 2008-10 Impact factor: 14.808
Authors: Zhouxin Shen; Elizabeth J Want; Wei Chen; William Keating; William Nussbaumer; Richard Moore; Thomas M Gentle; Gary Siuzdak Journal: J Proteome Res Date: 2006-11 Impact factor: 4.466
Authors: In-Seon Choi; Marcos R H Estecio; Yasuhiko Nagano; Do Ha Kim; Jill A White; James C Yao; Jean-Pierre J Issa; Asif Rashid Journal: Mod Pathol Date: 2007-05-04 Impact factor: 7.842
Authors: Holger Bang; Karl Egerer; Anke Gauliard; Kirsten Lüthke; Paul E Rudolph; Gert Fredenhagen; Wigbert Berg; Eugen Feist; Gerd-R Burmester Journal: Arthritis Rheum Date: 2007-08
Authors: Lisa G M van Baarsen; Carina L Bos; Tineke C T M van der Pouw Kraan; Cornelis L Verweij Journal: Arthritis Res Ther Date: 2009-01-30 Impact factor: 5.156