LRRK2 but not ATG16L1 is associated with Paneth cell defect in Japanese Crohn\u27s disease patients

Complementa esse poema o artigo “Shelley, poesia e liberdade” em verve dobras http://www.nu-sol.org/verve/verve1.php

LRRK2 but not ATG16L1 is associated with Paneth cell defect in Japanese Crohn\u27s disease patients

BACKGROUND. Morphological patterns of Paneth cells are a prognostic biomarker in Western Crohn’s disease (CD) patients, and are associated with autophagy-associated ATG16L1 and NOD2 variants. We hypothesized that genetic determinants of Paneth cell phenotype in other ethnic CD cohorts are distinct but also involved in autophagy. METHODS. We performed a hypothesis-driven analysis of 56 single nucleotide polymorphisms (SNPs) associated with CD susceptibility or known to affect Paneth cell function in 110 Japanese CD patients who underwent ileal resection. We subsequently performed a genome-wide association analysis. Paneth cell phenotype was determined by defensin-5 immunofluorescence. Selected genotype–Paneth cell defect correlations were compared to a Western CD cohort (n = 164). RESULTS. The average percentage of abnormal Paneth cells in Japanese CD was similar to Western CD (P = 0.87), and abnormal Paneth cell phenotype was also associated with early recurrence (P = 0.013). In contrast to Western CD, ATG16L1 T300A was not associated with Paneth cell defect in Japanese CD (P = 0.20). Among the 56 selected SNPs, only LRRK2 M2397T showed significant association with Paneth cell defect (P = 3.62 × 10(–4)), whereas in the Western CD cohort it was not (P = 0.76). Pathway analysis of LRRK2 and other candidate genes with P less than 5 × 10(–4) showed connections with known CD susceptibility genes and links to autophagy and TNF-α networks. CONCLUSIONS. We found dichotomous effects of ATG16L1 and LRRK2 on Paneth cell defect between Japanese and Western CD. Genes affecting Paneth cell phenotype in Japanese CD were also associated with autophagy. Paneth cell phenotype also predicted prognosis in Japanese CD. FUNDING. Helmsley Charitable Trust, Doris Duke Foundation (grant 2014103), Japan Society for the Promotion of Science (KAKENHI grants JP15H04805 and JP15K15284), Crohn’s and Colitis Foundation grant 274415, NIH (grants 1R56DK095820, K01DK109081, and UL1 TR000448)

Allele-specific DNA methylation of disease susceptibility genes in Japanese patients with inflammatory bowel disease.

BACKGROUND:Inflammatory bowel disease (IBD) has an unknown etiology; however, accumulating evidence suggests that IBD is a multifactorial disease influenced by a combination of genetic and environmental factors. The influence of genetic variants on DNA methylation in cis and cis effects on expression have been demonstrated. We hypothesized that IBD susceptibility single-nucleotide polymorphisms (SNPs) regulate susceptibility gene expressions in cis by regulating DNA methylation around SNPs. For this, we determined cis-regulated allele-specific DNA methylation (ASM) around IBD susceptibility genes in CD4+ effector/memory T cells (Tem) in lamina propria mononuclear cells (LPMCs) in patients with IBD and examined the association between the ASM SNP genotype and neighboring susceptibility gene expressions. METHODS:CD4+ effector/memory T cells (Tem) were isolated from LPMCs in 15 Japanese IBD patients (ten Crohn's disease [CD] and five ulcerative colitis [UC] patients). ASM analysis was performed by methylation-sensitive SNP array analysis. We defined ASM as a changing average relative allele score ([Formula: see text]) >0.1 after digestion by methylation-sensitive restriction enzymes. Among SNPs showing [Formula: see text] >0.1, we extracted the probes located on tag-SNPs of 200 IBD susceptibility loci and around IBD susceptibility genes as candidate ASM SNPs. To validate ASM, bisulfite-pyrosequencing was performed. Transcriptome analysis was examined in 11 IBD patients (seven CD and four UC patients). The relation between rs36221701 genotype and neighboring gene expressions were analyzed. RESULTS:We extracted six candidate ASM SNPs around IBD susceptibility genes. The top of [Formula: see text] (0.23) was rs1130368 located on HLA-DQB1. ASM around rs36221701 ([Formula: see text] = 0.14) located near SMAD3 was validated using bisulfite pyrosequencing. The SMAD3 expression was significantly associated with the rs36221701 genotype (p = 0.016). CONCLUSIONS:We confirmed the existence of cis-regulated ASM around IBD susceptibility genes and the association between ASM SNP (rs36221701) genotype and SMAD3 expression, a susceptibility gene for IBD. These results give us supporting evidence that DNA methylation mediates genetic effects on disease susceptibility

Allele-specific bisulfite pyrosequencing.

<p>To analyze the allele-specific DNA methylation, we individually measured the DNA methylation of each allele and compared methylation between the two alleles. Thus, the allele-specific polymerase chain reaction (PCR) was performed and the methylation levels of each of the two alleles, given allele-specific amplicons, were measured separately using pyrosequencing. The allele-specific PCR primers were designed such that each primer of 3′ end was a pair of base of heterozygous SNP. (a) The reference sequence of rs36221701 before and after bisulfite conversion. Rs36221701 contained two CpG sites denoted as CpG1 and CpG2 in 5′ to 3′ direction. By bisulfite conversion, unmethylated C is converted to U (U is converted to T by PCR). Rs362210701 (C/T) is converted to (T/T); it was impossible to distinguish the converted T and original T. Thus, we were unable to detect the origin of the allele for this SNP by PCR primers. (b) Allele-specific PCR. We designed PCR primer for rs13239907 (A/G), which is located 297 bp downstream of rs36221701 and was in complete linkage disequilibrium with rs36221701 (A→C, G→T: r² = 1.0) in JPT data from 1,000 genome project. The forward primer was common to both alleles; reverse primers were designed such that each primer of 3′ end was a pair of bases of genotypes (A or G: complementary strand). (c) Allele-specific pyrosequencing. The two given allele-specific amplicons were separately analyzed using pyrosequencing. Sequence primer 1 targeted rs13239907 and was used to check the accuracy of allele-specific PCR, whereas sequence primer 2 targeted CpG1 and CpG2 was used to analyze the ratio of methylation around rs36221701. (d) Primer details. The 3′ end of PCR primer R was a pair of base of heterozygous SNP. 5′ end of PCR primer R was biotinylated.</p

Flowchart of <i>cis</i>-regulating allele-specific DNA methylation SNP candidate selection around IBD susceptibility genes.

<p>SNP, single-nucleotide polymorphism; MSRE, methylation-sensitive restriction enzyme; RAS, relative allele score; IBD, inflammatory bowel disease; (G), genomic DNA; (D), DNA digested MSREs; (U), whole-genome-amplified fully unmethylated DNA digested MSREs.</p

Six of candidate <i>cis</i>-regulating allele-specific DNA methylation SNPs around inflammatory bowel disease susceptibility genes.

<p>Six of candidate <i>cis</i>-regulating allele-specific DNA methylation SNPs around inflammatory bowel disease susceptibility genes.</p

The relation between genotype of rs36221701 and the expression levels of genes around rs36221701.

<p>The relation between genotype of rs36221701 and the expression levels of genes around rs36221701.</p

The relation between rs36221701 genotype and SMAD3 expression.

<p>The scatter plot shows the expression levels of the genotypes.*Simple linear regression analysis.</p

Analysis of CpGs methylation levels around rs36221701 comparing with C and T allele in heterozygous samples.

<p>Analysis of CpGs methylation levels around rs36221701 comparing with C and T allele in heterozygous samples.</p