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Role of PTPN2/22 polymorphisms in pathophysiology of Crohn's disease.

ABSTRACT: To establish the relationship of protein tyrosine phosphatase non-receptor type 2 and 22 (PTPN2/22) polymorphisms and mycobacterial infections in Crohn's disease (CD).All 133 subjects' blood samples were genotyped for nine single nucleotide polymorphisms (SNPs) in PTPN2/22 using TaqMan™ genotyping, while the effect of the SNPs on PTPN2/22 and IFN-? gene expression was determined using RT-PCR. Detection of Mycobacterium avium subspecies paratuberculosis (MAP) IS900 gene was done by nPCR after DNA extraction from the isolated leukocytes of each subjects' blood samples. T-cells isolated from the patient samples were tested for response to phytohematoagglutonin (PHA) mitogen or mycobacterial antigens by BrdU proliferation assays for T-cell activity.Out of the nine SNPs examined, subjects with either heterozygous (TC)/minor (CC) alleles in PTPN2:rs478582 occurred in 83% of CD subjects compared to 61% healthy controls (P-values < 0.05; OR = 3.03). Subjects with either heterozygous (GA)/minor (AA) alleles in PTPN22:rs2476601 occurred in 16% of CD compared to 6% healthy controls (OR = 2.7). Gene expression in PTPN2/22 in CD subjects was significantly decreased by 2 folds compared to healthy controls (P-values < 0.05). IFN-? expression levels were found to be significantly increased by approxiately 2 folds in subjects when either heterozygous or minor alleles in PTPN2:rs478582 and/or PTPN22:rs2476601 were found (P-values < 0.05). MAP DNA was detected in 61% of CD compared to only 8% of healthy controls (P-values < 0.05, OR = 17.52), where subjects with either heterozygous or minor alleles in PTPN2:rs478582 and/or PTPN22:rs2476601 had more MAPbacteremia presence than subjects without SNPs did. The average T-cell proliferation in CD treated with PHA or mycobacteria antigens was, respectively, 1.3 folds and 1.5 folds higher than healthy controls without any significant SNP.The data suggests that SNPs in PTPN2/22 affect the negative regulation of the immune response in CD patients, thus leading to an increase in inflammation/apoptosis and susceptibility of mycobacteria.

SUBMITTER: Sharp RC

PROVIDER: S-EPMC5807669 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Role of <i>PTPN2/22</i> polymorphisms in pathophysiology of Crohn's disease.

Sharp Robert C RC Beg Shazia A SA Naser Saleh A SA

World journal of gastroenterology 20180201 6

<h4>Aim</h4>To establish the relationship of <i>protein tyrosine phosphatase non-receptor type 2 and 22</i> (<i>PTPN2/22</i>) polymorphisms and mycobacterial infections in Crohn's disease (CD).<h4>Methods</h4>All 133 subjects' blood samples were genotyped for nine single nucleotide polymorphisms (SNPs) in <i>PTPN2/22</i> using TaqMan™ genotyping, while the effect of the SNPs on <i>PTPN2/22</i> and <i>IFN-</i>γ gene expression was determined using RT-PCR. Detection of <i>Mycobacterium avium</i> s ...[more]

PMID: 29456405

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Project description:Crohn's Disease (CD) and Rheumatoid Arthritis (RA) share some single nucleotide polymorphisms (SNPs) in protein tyrosine phosphatase non-receptor types 2 and 22 (PTPN2/22). Recently, we reported that clinical samples from CD and RA patients associated with PTPN2:rs478582 or PTPN22:rs2476601 genotypes were linked to overactive immune response and exacerbation of inflammation. Here, we investigated in vitro the effects of these SNPs in Jurkat T-cells using CRISPR-Cas9. All cells were evaluated for PTPN22/22 loss of function and effects on cell response. We measured gene expression via RT-qPCR and cytokines by ELISA. We also measured cell proliferation using a BrdU labeling proliferation ELISA, and T-cell activation using CD-25 fluorescent immunostaining. In PTPN2 SNP-edited cells, PTPN2 expression decreased by 3.2-fold, and proliferation increased by 10.2-fold compared to control. Likewise, expression of PTPN22 decreased by 2.4-fold and proliferation increased by 8.4-fold in PTPN22 SNP-edited cells. IFN-γ and TNF-α secretions increased in both edited cell lines. CD25 expression (cell activation) was 80.32% in PTPN2 SNP-edited cells and 85.82% in PTPN22 SNP-edited cells compared to 70.48% in unedited Jurkat T-cells. Treatment of PTPN2 and PTPN22-edited cells with a maximum 20 μM spermidine restored PTPN2/22 expression and cell response including cell proliferation, activation, and cytokines secretion. Most importantly, the effect of spermidine on edited cells restored normal expression and secretion of IFN-γ and TNF-α. The data clearly demonstrated that edited SNPs in PTPN2 or PTPN22 were associated with reduced gene expression, which resulted in an increase in cell proliferation and activation and overactive immune response. The data validated our earlier observations in CD and RA clinical samples. Surprisingly, spermidine restored PTPN2/22 expression in edited Jurkat T-cells and the consequent beneficial effect on cell response and inflammation. The study supports the use of polyamines dietary supplements for management of CD and in RA patients.

Project description:A shared genetic pre-disposition, chronic inflammation, and treatment with similar biologics between Rheumatoid arthritis (RA) and Crohn's disease (CD) have intrigued us to investigate whether the two disorders share trigger association or possible causation. We hypothesized earlier that Single Nucleotide Polymorphisms (SNPs) in the negative regulators Protein Tyrosine Phosphatase Non-receptor type 2 and 22 (PTPN2/22) lead to a dysregulated immune response, susceptibility to environmental triggers, and continued apoptosis as seen in chronic inflammation in RA and CD. To test the hypothesis, peripheral leukocytes samples from 132 consented subjects were genotyped for 9 SNPs in PTPN2/22 using TaqMan™ genotyping. The effect of the SNPs on PTPN2/22 and IFN-γ expression was determined using real time PCR. T-cell proliferation and response to phytohematoagglutonin (PHA) mitogen and mycobacterial antigens were determined by BrdU proliferation assay. Blood samples were also analyzed for the Mycobacterium avium subspecies paratuberculosis (MAP) IS900 gene by nPCR. Out of 9 SNPs examined, heterozygous (TC) or minor (CC) alleles of PTPN2:rs478582 occurred in 79% RA compared to 60% healthy controls (p-values ≤ 0.05; OR = 2.28). Similarly, heterozygous (GA) or minor (AA) alleles of PTPN22:rs2476601 occurred in 29% RA compared to 6% healthy controls (p-values ≤ 0.05; OR = 5.90). PTPN2/22 expression in RA was decreased by 1.2-fold compared to healthy controls. PTPN2:rs478582 upregulated IFN-γ in RA by 1.5-fold. Combined PTPN2:rs478582 and PTPN22:rs2476601 increased T-cell proliferation by 2.7-fold when treated with PHA. Surprisingly, MAP DNA was detected in 34% of RA samples compared to 8% healthy controls, (p-values ≤ 0.05, OR = 5.74). RA samples with PTPN2:rs478582 and/or PTPN22:rs2476601 were more positive for MAP than samples without polymorphisms. Combined occurrence of PTPN2:rs478582 and PTPN22:rs2476601 in association with the presence of MAP has significantly increased T-cell response and elevated IFN-γ expression in RA samples. The data suggest that genetic polymorphisms may play vital role in T-cell regulation, susceptibility to mycobacteria and ultimately response to treatment. This is the first study to report the detection of MAP DNA in the blood of RA patients; further studies are needed using larger number of samples.

Project description:BACKGROUND: Genome-wide association studies identified PTPN2 (protein tyrosine phosphatase, non-receptor type 2) as susceptibility gene for inflammatory bowel diseases (IBD). However, the exact role of PTPN2 in Crohn's disease (CD) and ulcerative colitis (UC) and its phenotypic effect are unclear. We therefore performed a detailed genotype-phenotype and epistasis analysis of PTPN2 gene variants. METHODOLOGY/PRINCIPAL FINDINGS: Genomic DNA from 2131 individuals of Caucasian origin (905 patients with CD, 318 patients with UC, and 908 healthy, unrelated controls) was analyzed for two SNPs in the PTPN2 region (rs2542151, rs7234029) for which associations with IBD were found in previous studies in other cohorts. Our analysis revealed a significant association of PTPN2 SNP rs2542151 with both susceptibility to CD (p?=?1.95×10??; OR 1.49 [1.34-1.79]) and UC (p?=?3.87×10?², OR 1.31 [1.02-1.68]). Moreover, PTPN2 SNP rs7234029 demonstrated a significant association with susceptibility to CD (p?=?1.30×10?³; OR 1.35 [1.13-1.62]) and a trend towards association with UC (p?=?7.53×10?²; OR 1.26 [0.98-1.62]). Genotype-phenotype analysis revealed an association of PTPN2 SNP rs7234029 with a stricturing disease phenotype (B2) in CD patients (p?=?6.62×10?³). Epistasis analysis showed weak epistasis between the ATG16L1 SNP rs2241879 and PTPN2 SNP rs2542151 (p?=?0.024) in CD and between ATG16L1 SNP rs4663396 and PTPN2 SNP rs7234029 (p?=?4.68×10?³) in UC. There was no evidence of epistasis between PTPN2 and NOD2 and PTPN2 and IL23R. In silico analysis revealed that the SNP rs7234029 modulates potentially the binding sites of several transcription factors involved in inflammation including GATA-3, NF-?B, C/EBP, and E4BP4. CONCLUSIONS/SIGNIFICANCE: Our data confirm the association of PTPN2 variants with susceptibility to both CD and UC, suggesting a common disease pathomechanism for these diseases. Given recent evidence that PTPN2 regulates autophagosome formation in intestinal epithelial cells, the potential link between PTPN2 and ATG16L1 should be further investigated.

Project description:Crohn's disease (CD) and celiac disease (CelD) are chronic intestinal inflammatory diseases, involving genetic and environmental factors in their pathogenesis. The two diseases can co-occur within families, and studies suggest that CelD patients have a higher risk to develop CD than the general population. These observations suggest that CD and CelD may share common genetic risk loci. Two such shared loci, IL18RAP and PTPN2, have already been identified independently in these two diseases. The aim of our study was to explicitly identify shared risk loci for these diseases by combining results from genome-wide association study (GWAS) datasets of CD and CelD. Specifically, GWAS results from CelD (768 cases, 1,422 controls) and CD (3,230 cases, 4,829 controls) were combined in a meta-analysis. Nine independent regions had nominal association p-value <1.0 x 10?? in this meta-analysis and showed evidence of association to the individual diseases in the original scans (p-value < 1 x 10?² in CelD and < 1 x 10?³ in CD). These include the two previously reported shared loci, IL18RAP and PTPN2, with p-values of 3.37 x 10?? and 6.39 x 10??, respectively, in the meta-analysis. The other seven had not been reported as shared loci and thus were tested in additional CelD (3,149 cases and 4,714 controls) and CD (1,835 cases and 1,669 controls) cohorts. Two of these loci, TAGAP and PUS10, showed significant evidence of replication (Bonferroni corrected p-values <0.0071) in the combined CelD and CD replication cohorts and were firmly established as shared risk loci of genome-wide significance, with overall combined p-values of 1.55 x 10?¹? and 1.38 x 10?¹¹ respectively. Through a meta-analysis of GWAS data from CD and CelD, we have identified four shared risk loci: PTPN2, IL18RAP, TAGAP, and PUS10. The combined analysis of the two datasets provided the power, lacking in the individual GWAS for single diseases, to detect shared loci with a relatively small effect.

Dataset Information

Role of PTPN2/22 polymorphisms in pathophysiology of Crohn's disease.

Publications

Role of <i>PTPN2/22</i> polymorphisms in pathophysiology of Crohn's disease.

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