The PADI4 gene does not contribute to genetic susceptibility to rheumatoid arthritis in Chinese Han population

Molecular Factors in PAD2 (PADI2) and PAD4 (PADI4) Are Associated with Interstitial Lung Disease Susceptibility in Rheumatoid Arthritis Patients

Around 50% of rheumatoid arthritis (RA) patients show some extra-articular manifestation, with the lung a usually affected organ; in addition, the presence of anti-citrullinated protein antibodies (ACPA) is a common feature, which is caused by protein citrullination modifications, catalyzed by the peptidyl arginine deiminases (PAD) enzymes. We aimed to identify single nucleotide variants (SNV) in PADI2 and PADI4 genes (PAD2 and PAD4 proteins, respectively) associated with susceptibility to interstitial lung disease (ILD) in RA patients and the PAD2 and PAD4 levels. Material and methods: 867 subjects were included: 118 RA-ILD patients, 133 RA patients, and 616 clinically healthy subjects (CHS). Allelic discrimination was performed in eight SNVs using qPCR, four in PADI2 and four in PADI4. The ELISA technique determined PAD2 and PAD4 levels in serum and bronchoalveolar lavage (BAL) samples, and the population structure was evaluated using 14 informative ancestry markers. Results: The rs1005753-GG (OR = 4.9) in PADI2 and rs11203366-AA (OR = 3.08), rs11203367-GG (OR = 2.4) in PADI4 are associated with genetic susceptibility to RA-ILD as well as the ACTC haplotype (OR = 2.64). In addition, the PAD4 protein is increased in RA-ILD individuals harboring the minor allele homozygous genotype in PADI4 SNVs. Moreover, rs1748033 in PADI4, rs2057094, and rs2076615 in PADI2 are associated with RA susceptibility. In conclusion, in RA patients, single nucleotide variants in PADI4 and PADI2 are associated with ILD susceptibility. The rs1748033 in PADI4 and two different SNVs in PADI2 are associated with RA development but not ILD. PAD4 serum levels are increased in RA-ILD patients.

SNP in PTPN22, PADI4, and STAT4 but Not TRAF1 and CD40 Increase the Risk of Rheumatoid Arthritis in Polish Population

Single nucleotide polymorphisms in non-HLA genes are involved in the development of rheumatoid arthritis (RA). SNPS in genes: PADI4 (rs2240340), STAT4 (rs7574865), CD40 (rs4810485), PTPN22 (rs2476601), and TRAF1 (rs3761847) have been described as risk factors for the development of autoimmune diseases, including RA. This study aimed to assess the prevalence of polymorphisms of these genes in the Polish population of patients with rheumatoid arthritis as compared to healthy controls. 324 subjects were included in the study: 153 healthy subjects and 181 patients from the Department of Rheumatology, Medical University of Lodz who fulfilled the criteria of rheumatoid arthritis diagnosis. Genotypes were determined by Taqman SNP Genotyping Assay. rs2476601 (G/A, OR = 2.16, CI = 1.27-3.66; A/A, OR = 10.35, CI = 1.27-84.21), rs2240340 (C/T, OR = 4.35, CI = 2.55-7.42; T/T, OR = 2.80, CI = 1.43-4.10) and rs7574865 (G/T, OR = 1.97, CI = 1.21-3.21; T/T, OR = 3.33, CI = 1.01-11.02) were associated with RA in the Polish population. Rs4810485 was also associated with RA, however after Bonferroni's correction was statistically insignificant. We also found an association between minor alleles of rs2476601, rs2240340, and rs7574865 and RA (OR = 2.32, CI = 1.47-3.66; OR = 2.335, CI = 1.64-3.31; OR = 1.88, CI = 1.27-2.79, respectively). Multilocus analysis revealed an association between CGGGT and rare (below 0.02 frequency) haplotypes (OR = 12.28, CI = 2.65-56.91; OR = 3.23, CI = 1.63-6.39). In the Polish population, polymorphisms of the PADI4, PTPN22, and STAT4 genes have been detected, which are also known risk factors for RA in various other populations.

PADI4 and IL-33 gene polymorphisms associated with differential susceptibility to juvenile-onset systemic lupus erythematosus and juvenile idiopathic arthritis in Chinese children

BACKGROUND

Juvenile systemic lupus erythematosus (JSLE) and juvenile idiopathic arthritis (JIA) are two common types of autoimmune diseases in children with unclear pathogenesis. Both peptidyl arginine deiminase type IV (PADI4) and interleukin 33 (IL-33) are the key molecular involved in immune responses in autoimmune diseases. Usually, it may share the same risk genetic alleles for autoimmune diseases.

METHODS

So measurement of PADI4 and IL-33 polymorphisms was conducted with 303 healthy controls, 144 JSLE patients and 160 JIA patients in this study.

RESULTS

It demonstrated that there was a significant association between PADI4 genotypes (rs2240340: CT, CT + CC), IL-33 genotype (rs1929992: TT) and JSLE susceptibility in Southwest China population. While no significant association with the risk of JIA were observed no matter at allelic or genotypic levels.

CONCLUSIONS

Our study reveals the importance of PADI4 and IL-33 polymorphisms with JSLE risk and their roles in the development of the diseases need more further researches.

Novel functional polymorphism on PADI-4 gene and its association with arthritis onset

Background

Citrullinated proteins formed by peptidyl arginine deiminases (PADIs) deimination of arginine residues in proteins are of particular interest in arthritis pathogenesis. Polymorphisms on the PADI-4 gene lead to the malfunctioning of PADIs leading to the onset of arthritis.

Objective

The present study was conducted to determine the polymorphisms on the PADI-4 gene and their association with rheumatoid arthritis (RA) as well as Osteoarthritis (OA).

Methodology

To achieve the above-mentioned objective a case-control study was conducted. Blood samples were collected from RA, OA, and control subjects. DNA was extracted from each blood sample by modified organic method and was quantified as well as qualified by DNA gel electrophoresis and Nanodrop. Patients were tested for rs874881, rs11203366, rs11203367, rs2240336, rs2240337, rs2240339, rs1748033 and rs2240340 polymorphic sites by amplifying targeted regions through PCR with site-specific primers. Genotyping was performed by Restriction Fragment Length Polymorphism and direct sequencing method. Mutations were identified by analyzing sequences on BioEdit software. Allelic, genetic, and multiple site analysis were performed by SHEsis and PLINK software. Change in the amino acid sequence was identified by MEGA 6.0 software.

Results

Polymorphisms were identified on all targeted polymorphic sites except rs2240337 in both RA and OA individuals. In addition, two novel mutations were also identified in exon 4 identified i-e SCV000804840: c.218T > C and SCV000807675: c.241G > T. All the SNPs except rs11203366 were found to be significantly associated with RA at an allelic level whereas all SNP’s have been significant risk factors in the onset of OA. At genotypic level rs874881, rs11203366, rs2240339, SCV000804840 and SCV000807675 were significantly associated to RA development whereas rs874881, rs11203366, rs11203367, rs2240339, SCV000804840 and SCV000807675 were genetic risk factors in OA onset. Haplotype analysis indicated that GACCACGCC and GACCACGCT were highly significant in disease development. Polymorphisms identified altered the functioning of PADIs by altering their amino acid sequence.

Conclusion

In conclusion, it was found that PADI-4 gene polymorphism was not only involved in the onset of RA but was also found to be a significant risk factor in OA onset.

Peptidylarginine deiminase 4 -104C/T polymorphism and risk of rheumatoid arthritis: A pooled analysis based on different populations

Background

Many studies have analyzed the association between peptidylarginine deiminase 4 (PADI4) -104C/T polymorphism and rheumatoid arthritis (RA). However, the results are inconsistent. This meta-analysis, based on different populations, updated and reevaluated the possible associations between PADI4 -104C/T polymorphism and the susceptibility to RA.

Methods

A literature search was performed on PubMed and related Chinese databases up to April 2017. The association between PADI4 -104C/T polymorphism and RA risk was evaluated by calculating pooled odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of seventeen studies, including 5,756 RA cases and 4,987 controls, were screened out. In the overall population, PADI -104C/T polymorphism was significantly associated with an increased RA risk. In this meta-analysis stratified by ethnicity, a significant association between PADI -104C/T polymorphism and RA risk was established in China and Japan.

Conclusions

Our study indicated a significantly increased association between PADI -104C/T polymorphism and RA in Chinese and Japanese populations. Because most included populations in this meta-analysis were Asian, further studies are needed to elucidate whether the PADI4 -104C/T gene confers RA in other ethnic groups.

Meta-analysis of the association between PADI4 -92C/G polymorphism and rheumatoid arthritis in the Chinese population

Many studies have evaluated the correlation between peptidylarginine deiminase 4 (PADI4) -92C/G polymorphism and rheumatoid arthritis (RA), but the results remain inconclusive. Therefore, we performed a meta-analysis in the Chinese population to provide comprehensive data on the association between PADI4 -92C/G polymorphism and RA. Eligible studies published before May 2016 were identified in PubMed and Chinese databases. The strengths of these associations were assessed by pooled odds ratios (OR) and 95% confidence interval (CI). Eight studies documenting a total of 1351 RA cases and 1585 controls were included in this meta-analysis. In the overall analysis, a significant association between the PADI4 -92C/G polymorphism and RA was found in the Chinese population (G vs C: OR=1.32, 95%CI=1.02-1.71; GG+CG vs CC: OR=1.75, 95%CI=1.20-2.53). The subgroup analyses stratified by geographic area(s) and source of controls revealed significant results in South China, in hospital-based studies and population-based studies. In summary, this meta-analysis suggested that PADI4 -92C/G polymorphism may be associated with the RA incidence in the Chinese population, especially for South China. Further studies conducted on other ethnic groups are required for definite conclusions.

NLRP1, PTPN22 and PADI4 gene polymorphisms and rheumatoid arthritis in ACPA-positive Singaporean Chinese

Studies have shown that the genetic risk factors for rheumatoid arthritis (RA) differ substantially between Asian and Caucasian populations. Even among Asian populations, the genetic contributions of NLRP1, PTPN22 and PADI4 have been controversial. Consequently, we sought to address these separate findings and determine whether any of these proposed risk variants are associated with RA susceptibility, onset, DAS activity and erosion in a Singaporean Chinese cohort. We genotyped five SNPs within NLRP1 (rs878329 and rs6502867), PTPN22 (rs2488457 and rs6665194), and PADI4 (rs2240340) in 500 anti-cyclic citrullinated peptide antibody-positive (ACPA) patients with RA and 500 healthy controls using TaqMan assays. The CC genotype of NLRP1 rs878329 and TT genotype of PADI4 rs2240340 were associated with RA susceptibility. The risk association of the T allele of PADI4 rs2240340 with RA was confirmed through a meta-analysis based on previous reports in Asian populations. The GG genotype of PTPN22 rs6665194 (-3508A>G) was associated with significantly reduced risk of RA. No significant association was found for NLRP1 rs6502867 T/C and PTPN22 rs2488457 G/C polymorphisms. None of the five SNPs was associated with RA's clinical features. This work supports the association of the T allele of PADI4 rs2240340 with RA in Asians. The roles of NLRP1 rs878329 G/C and PTPN22 rs6665194 A/G polymorphisms were demonstrated for the first time. We also propose rs6665194 to be a promising candidate for RA risk evaluation between ethnicities.

PADI4 polymorphisms and the functional haplotype are associated with increased rheumatoid arthritis susceptibility: A replication study in a Southern Mexican population

Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The peptidyl arginine deiminase type IV (PADI4) gene has been associated with RA susceptibility in several populations. We addressed the relationship between three exonic PADI4 gene single nucleotide polymorphisms (SNPs) PADI4_89 (rs11203366), PADI4_90 (rs11203367) and PADI4_92 (rs874881) and related haplotypes with RA in a population from Southern México. This study included 200 RA patients and 200 control subjects. The SNPs were evaluated using the polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) technique, and antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA). In this population, the minor alleles of PADI4_89∗G, PADI4_90∗T and PADI4_92∗G gene polymorphisms were associated with RA susceptibility (OR=1.34, p=0.04; OR=1.35, p=0.03; OR=1.34, p=0.04; respectively). The GTG haplotype was also significantly associated with RA (OR=2.27 95%CI=1.18-4.41; p=0.008), but did not show association with levels of anti-CCP antibodies and clinical parameters. In conclusion, our replication study in a Southern Mexican population suggests that PADI4 individual polymorphisms and the related susceptibility haplotype (GTG) are also genetic risk markers for RA.

Associations Between PADI4 Gene Polymorphisms and Rheumatoid Arthritis: An Updated Meta-analysis

BACKGROUND AND AIMS

Studies investigating the association between the peptidylarginine deiminase 4 (PADI4) gene polymorphisms and rheumatoid arthritis (RA) reported conflicting results. The aim of this meta-analysis was to assess the association between PADI4 gene polymorphisms and RA.

METHODS

A systematic literature search was conducted to identify relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of the association.

RESULTS

A total of 34 studies from 28 articles involving 19859 patients with RA and 25771 healthy controls were included. Significant association of PADI4-94G/A polymorphism and RA was observed (OR = 0.891, 95% CI = 0.833-0.954, p = 0.001) in the overall study population and in the Asian populations (OR = 0.824, 95% CI = 0.759-0.894, p = 0.000) respectively. For the -92C/G polymorphism, a significant association was observed (OR = 1.481, 95% CI = 1.166-1.882, p = 0.001) in Africans. For the -90C/T polymorphism, a significant association was observed (OR = 0.576, 95% CI = 0.381-0.872, p = 0.009) in the Latin American population. The pooled estimates for the other polymorphisms were not statistically significantly associated with RA (PADI4-104C/T, -89A/G, -96T/C).

CONCLUSIONS

This meta-analysis demonstrates that PADI4-94G/A polymorphism is associated with susceptibility to RA in the overall population and in the Asian population. The PADI4 -92C/G polymorphism confers susceptibility to RA in Africans and the PADI4-90C/T polymorphism was associated with RA in the Latin American population.

PADI2 is significantly associated with rheumatoid arthritis

Citrullination, a posttranslational modification of peptidyl arginine to citrulline, plays an essential role in rheumatoid arthritis (RA). Citrullination is catalyzed by a group of peptidylarginine deiminases (PADs) including PADI 1, 2, 3, 4 and 6. Many studies have indicated that the gene encoding PADI4 is a factor in susceptibility to RA. Some studies have detected PADI2 expression in RA synovial tissues, suggesting that PADI2 also plays an important role in the disease. This study evaluated the possible association between the PADI2-encoding gene and RA. Seventeen tag SNPs across the PAD locus were genotyped using a custom-designed Illumina 96-SNP VeraCode microarray. Peripheral blood samples were collected from patients with RA (n = 267), ankylosing spondylitis (AS, n = 51) and healthy controls (n = 160). The results of genotyping were verified using Sequenom MassARRAY in an independent cohort of 307 patients with RA, 324 patients with AS and 509 healthy controls. A western blot analysis was performed using synovial tissue from patients with RA (n = 7), osteoarthritis (OA, n = 7) and AS (n = 5) to determine the levels of expression of PADI2. A microarray analysis revealed a significant association between three selected PADI2 SNPs (rs2235926, rs2057094, rs2076616) and the presence of RA. The increased susceptibility to RA associated with rs2235926 (OR = 1.706733, 95% CI = [1.576366–1.866587], p = 0.000839) and rs2057094 (OR = 1.360432, 95% CI = [1.065483–1.869482], p = 0.003291) was further confirmed by the Sequenom MassARRAY. No tag SNPs in the PADI2 locus showed a significant association with AS. Increased expression of PADI2 was detected in RA synovial tissues compared with samples from patients with OA and AS. PADI2 is significantly associated with RA and may be involved in the pathogenesis of the disease.

Polymorphisms in peptidylarginine deiminase associate with rheumatoid arthritis in diverse Asian populations: evidence from MyEIRA study and meta-analysis

Introduction

The majority of our knowledge regarding disease-related mechanisms of uncontrolled citrullination and anti-citrullinated protein antibody development in rheumatoid arthritis (RA) was investigated in Caucasian populations. However, peptidylarginine deiminase (PADI) type 4 gene polymorphisms are associated with RA in East Asian populations and weak or no association was found in Caucasian populations. This study explores the association between the PADI4 polymorphisms and RA risk in a multiethnic population residing in South East Asia with the goal of elucidating generalizability of association in non-Caucasian populations.

Methods

A total of 320 SNPs from the PADI locus (including PADI1, PADI2, PADI3, PADI4 and PADI6 genes) were genotyped in 1,238 RA cases and 1,571 control subjects from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA) case-control study. Additionally, we conducted meta-analysis of our data together with the previously published studies of RA from East Asian populations.

Results

The overall odds ratio (OR_overall) for the PADI4 (rs2240340) allelic model was 1.11 (95% confidence interval (CI) = 1.00 to 1.23, P = 0.04) and for the genotypic model was 1.20 (95% CI = 1.01 to 1.44, P = 0.04). Haplotype analysis for four selected PADI4 SNPs revealed a significant association of one with susceptibility (P = 0.001) and of another with a protective effect (P = 0.02). The RA susceptibility was further confirmed when combined meta-analysis was performed using these data together with data from five previously published studies from Asia comprising 5,192 RA cases and 4,317 control subjects (OR_overall = 1.23 (95% CI = 1.16 to 1.31, P_{heterogeneity} = 0.08) and 1.31 (95% CI = 1.20 to 1.44, P_{heterogeneity} = 0.32) in allele and genotype-based models, respectively). In addition, we also detected a novel association of PADI2 genetic variant rs1005753 with RA (OR_overall = 0.87 (95% CI = 0.77 to 0.99)).

Conclusion

Our study demonstrates an association between PADI4 and RA in the multiethnic population from South East Asia and suggests additional association with a PADI2 gene. The study thus provides further support for the notion that polymorphisms in genes for enzymes responsible for citrullination contribute to RA development in multiple populations of Asian descent.

PADI4 polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis

The objective of the study was to investigate the association between peptidylarginine deiminase 4 (PADI4) polymorphism and susceptibility to rheumatoid arthritis (RA). An electronic searching strategy was employed to collect relevant studies on the association between PADI4 polymorphism and susceptibility to RA. The odds ratio (OR) with the 95 % confidence interval (95 % CI) was used to evaluate the RA risk presented by PADI4 polymorphism. Fixed or random effects models were selected based on heterogeneity. Publication bias was assessed using funnel plots, Begg's test, and Egger's test. A total of 27 studies from 21 articles were included. Six gene loci (padi4_94, 104, 92, 90, 89, and 100) were chosen for the meta-analysis. The pooled ORs (95 % CI) for allele 2 versus 1 were 1.08 (1.05-1.12), 1.17 (1.12-1.23), 1.26 (1.18-1.36), 1.17 (1.10-1.24), 1.30 (1.17-1.44), and 1.25 (1.11-1.40), respectively. All six SNPs were significantly associated with RA in Asian populations. Three SNPs (PADI4_104, 90, 89) showed significant associations, while the other three SNPs (PADI4_94, 92, 100) exhibited no associations in the European population. A dose-response relationship between allele 2 of PADI4 and the risk of RA was also identified. In conclusion, this meta-analysis suggests that PADI4 polymorphisms represent a significant risk factor for RA, especially in Asians.