PADI4 Haplotypes Research Articles

PADI4 Haplotypes Contribute to mRNA Expression, the Enzymatic Activity of Peptidyl Arginine Deaminase and Rheumatoid Arthritis Risk in Patients from Western Mexico.

Citrullination is catalyzed by the peptidyl arginine deiminase 4 (PAD4) enzyme, encoded by the PADI4 gene. Increased PAD4 activity promotes the onset and progression of rheumatoid arthritis (RA). This study aimed to evaluate the association of PADI4 haplotypes with RA risk, mRNA expression, and the PAD4 activity in patients with RA from Mexico. Methodology: 100 RA patients and 100 control subjects (CS) were included. Genotyping was performed by PCR-RFLP method, PADI4 mRNA expression was quantified by real-time PCR, the contribution of PADI4 alleles (PADI4_89 G>A, PADI4_90 T>C, and PADI4_92 G>C) to mRNA expression by the ASTQ method, and PAD4 activity by HPLC. Also, the anti-CCP and anti-PADI4 antibodies were quantified by ELISA. Results: The three PADI4 polymorphisms were associated with RA susceptibility (OR = 1.72, p = 0.005; OR = 1.62; p = 0.014; OR = 1.69; p = 0.009; respectively). The 89G, 90T, and 92G alleles have a higher relative contribution to PADI4 mRNA expression from RA patients than 89A, 90C, and 92C alleles in RA patients. Moreover, the GTG/GTG haplotype was associated with RA susceptibility (OR = 2.86; p = 0.024). The GTG haplotype was associated with higher PADI4 mRNA expression (p = 0.04) and higher PAD4 enzymatic activity (p = 0.007) in RA patients. Conclusions: The evaluated polymorphisms contribute to PADI4 mRNA expression and the enzymatic activity of PAD4 in leukocytes. Therefore, the GTG haplotype is a genetic risk factor for RA in western Mexico, and is associated with increased PADI4 mRNA expression and higher PAD4 activity in these patients.

Polymorphisms and functional haplotype in PADI4: Further evidence for contribution on rheumatoid arthritis susceptibility and anti-cyclic citrullinated peptide antibodies in a western Mexican population

Peptidyl arginine deiminase IV (PADI4) enzyme catalyzes the citrullination of proteins, which are recognized by anti-cyclic citrullinated peptide antibodies (anti-CCP) in rheumatoid arthritis (RA) patients. Here, we determined the association between PADI4 gene polymorphisms and haplotypes with RA susceptibility and clinical characteristics in a western Mexican population. The relationship of PADI4 polymorphisms with anti-CCP and PADI4 mRNA expression was also evaluated. PADI4_89, PADI4_90 and PADI4_92 polymorphisms were individually associated with RA susceptibility. The GTG haplotype was significantly associated with: RA susceptibility; disease onset at ≤40 years and anti-CCP antibodies. PADI4 expression was three fold higher in RA patients carrying the susceptibility haplotype (GTG) than in non-susceptibility haplotype carriers (ACC). In conclusion, polymorphisms and functional haplotype (GTG) in PADI4 are associated with RA susceptibility as well as anti-CCP antibodies in a Mexican population. This supports the role of PADI4 early in RA pathogenesis by promoting the generation of citrullinated autoantigens.

AB0181 Padi4 haplotype a potential modulator of antigen expression in an immunological environment

BackgroundPeptidil arginine deiminase IV (PAD 4) is the responsible enzyme for a posttranslational modification called citrullination, originating the antigenic determinant recognized by anti-cyclic citrullinated peptide antibodies (aCCP)1. Four SNPs (single...

PADI4 Haplotypes in Association with RA Mexican Patients, a New Prospect for Antigen Modulation

Peptidyl arginine deiminase IV (PAD 4) is the responsible enzyme for a posttranslational modification called citrullination, originating the antigenic determinant recognized by anti-cyclic citrullinated peptide antibodies (ACPA). Four SNPs (single nucleotide polymorphisms) have been described in PADI4 gene to form a susceptibility haplotype for rheumatoid arthritis (RA); nevertheless, results in association studies appear contradictory in different populations. The aim of the study was to analyze if the presence of three SNPs in PADI4 gene susceptibility haplotype (GTG) is associated with ACPA positivity in patients with RA. This was a cross-sectional study that included 86 RA patients and 98 healthy controls. Polymorphisms PADI4_89, PADI4_90, and PADI4_92 in the PADI4 gene were genotyped. The susceptibility haplotype (GTG) was more frequent in RA patients; interestingly, we found a new haplotype associated with RA with a higher frequency (GTC). There were no associations between polymorphisms and high scores in Spanish HAQ-DI and DAS-28, but we did find an association between RARBIS index and PADI4_89, PADI4_90 polymorphisms. We could not confirm an association between susceptibility haplotype presence and ACPA positivity. Further evidence about proteomic expression of this gene will determine its participation in antigenic generation and autoimmunity.

Effect of Rheumatoid Arthritis (RA) Susceptibility Genes on the Immune Response to Viral Citrullinated Peptides in RA

To the Editor: Anticitrullinated peptide/protein antibodies (ACPA) are a family of rheumatoid arthritis (RA)-specific antibodies that recognize various protein sequences containing citrulline, the deiminated form of arginine produced posttranslationally by peptidylarginine deiminase (PAD) enzymes. Recently, viral citrullinated peptides (VCP) derived from Epstein-Barr virus nuclear proteins EBNA-1 and EBNA-2 have been described as a target of ACPA in RA sera1,2. Genetic factors predisposing to RA, namely HLA-DRB1 shared epitope (SE) alleles and PTPN22 gene variants, as well as the TRAF1/C5 locus and PADI4 susceptible haplotype, have been found to be predominantly associated with ACPA-positive RA, even if the association with ACPA-negative RA cannot be excluded. We evaluated the influence of genes conferring susceptibility to RA on the production of anti-VCP antibodies and tested the interaction of VCP with HLA in vitro . We analyzed 172 patients with RA of French white origin3. All provided informed consent and the Ethics Committee of Hopital Bicetre (AP-HP, Paris, France) approved the study. HLA-DRB1 typing and subtyping were performed by a polymerase chain reaction (PCR)-based method, using a panel of sequence-specific oligonucleotide probes. PADI4 haplotypes were obtained by typing 3 single-nucleotide polymorphisms (SNP: rs1886303, PADI4\_92, PADI4\_96 – CGC haplotype) by PCR-restriction fragment-length polymorphism (RFLP)4. PTPN22 (R620W; rs24766601 – T variant) and C5/TRAF1 region polymorphisms (rs10818488 – A variant) were genotyped by PCR-RFLP5,6. … Address correspondence to Dr. P. Migliorini; E-mail: paola.migliorini{at}med.unipi.it

PADI4 polymorphisms and related haplotype in rheumatoid arthritis patients

ObjectiveTo investigate whether peptidyl arginine deiminase type IV gene (PADI4) polymorphisms contribute to rheumatoid arthritis (RA) susceptibility in Egyptians, whether they influence disease severity and activity, and whether they affect anti-mutated citrullinated vimentin antibodies (anti-MCV) level. MethodsThree PADI4 single nucleotide polymorphisms (SNPs) (PADI4-92, PADI4-96, and PADI4-102) were screened in 275 RA patients and 275 unaffected controls by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method. Serum anti-MCV levels were measured by enzyme-linked immunosorbent assay (ELISA). ResultsThere were significant associations between RA susceptibility with the minor alleles of PADI4-92 and PADI4-102 [odds ratio (OD) and 95% confidence interval (CI) for the minor alleles of PADI4-92 and PADI4-102: 1.48 (1.17–1.88) and 2.05 (1.61–2.61) respectively] but not with PADI4-96 [OD and 95% CI for the C allele: 1.09 (0.86–1.39)]. PADI4 haplotypes 2 (GCC) and 3 (GCT) were also associated with RA susceptibility while PADI4 haplotypes 1 (CTC) may be protective against developing of this disease. A significant association was detected between PADI4 haplotypes and RA severity. ConclusionsThe PADI4 SNPs and haplotypes were associated with RA susceptibility, although no relation was observed between the PADI4 haplotypes and anti-MCV levels.

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

The Peptidyl arginine deiminase, type IV (PADI4) gene has been suggested to have an association with rheumatoid arthritis (RA) in several populations. But its role in Chinese RA is not clarified. We investigated five single-nucleotide polymorphisms (SNPs) of PADI4 as PADI4-89 (rs11203366), PADI4-90 (rs11203367), PADI4-92 (rs874881) PADI4-94 (rs2240340), and PADI4-104 (rs1748033) in Chinese Han population. A total of 378 unrelated RA patients and 204 healthy controls were genotyped for the five SNPs. Individual allele, genotype and haplotype frequencies were compared between patients and controls. No significant differences in the frequency of PADI4 alleles, genotypes and haplotypes were observed between the patients and controls except PADI4-92. These data indicated that PADI4 polymorphisms were unlikely to play an important role in the susceptibility to RA in Chinese Han population.

Contribution of anti-CCP antibodies, proximal interphalangeal joint involvement, HLA-DRB1 shared epitope, and PADI4 as risk factors for the development of rheumatoid arthritis in palindromic rheumatism

Objectives: To determine which variables at baseline are predictive for the development of rheumatoid arthritis (RA) from palindromic rheumatism (PR) in a Japanese population.Methods: Anti-cyclic citrullinated peptide (anti-CCP) antibodies, joint involvement pattern, genotypes of HLA-DRB1, peptidylarginine deiminase (PADI4), and protein tyrosine phosphatase (PTPN22) were examined in 28 patients with PR at baseline, and their clinical outcome was prospectively evaluated. The same variables were also investigated in 38 healthy controls.Results: Eleven out of 28 patients with PR developed RA. The prevalence of anti-CCP antibodies in the PR patients who developed RA was significantly higher compared to the patients who did not. Proximal interphalangeal (PIP) joint involvement at baseline was also predictive towards the development of RA. Compared with the controls, differences in the frequency of single-nucleotide polymorphism (SNP) on padi4_104 [T(RA susceptible)→C(RA non-susceptible)] and the presence of an RA susceptible homozygote of the PADI4 haplotype were detected in patients with PR whereas we could not find any further difference in PR patients who developed RA compared to PR patients who do not develop RA in PADI4. None of the subjects possessed the PTPN22 SNP (1858C→T). Cox regression analysis revealed that anti-CCP antibodies as well as PIP involvement are the most relevant variables for the development of RA from PR. None of the PR patients with either HLA-DRB1*SE alleles (or the HLA-DRB1*0405 allele) or anti-CCP antibodies developed RA.Conclusions: Anti-CCP antibodies, in relation to HLA-DRB1*SE carriership, and PIP involvement are predictive for the development of RA from PR in the Japanese population.

Peptidyl arginine deiminase type IV (PADI4) haplotypes interact with shared epitope regardless of anti-cyclic citrullinated peptide antibody or erosive joint status in rheumatoid arthritis: a case control study

IntroductionAnti-cyclic citrullinated peptide autoantibodies (anti-CCP) are the most specific serologic marker for rheumatoid arthritis (RA). Genetic polymorphisms in a citrullinating (or deiminating) enzyme, peptidyl arginine deiminase type IV (PADI4) have been reproducibly associated with RA susceptibility in several populations. We investigated whether PADI4 polymorphisms contribute to anti-CCP-negative as well as -positive RA, whether they influence disease severity (erosive joint status), and whether they interact with two major risk factors for RA, Human Leukocyte Antigen-DRB1 (HLA-DRB1) shared epitope (SE) alleles and smoking, depending on anti-CCP and erosive joint status.MethodsAll 2,317 unrelated Korean subjects including 1,313 patients with RA and 1,004 unaffected controls were genotyped for three nonsynonymous (padi4_89, padi4_90, and padi4_92) and one synonymous (padi4_104) single-nucleotide polymorphisms (SNPs) in PADI4 and for HLA-DRB1 by direct DNA sequence analysis. Odds ratios (OR) were calculated by multivariate logistic regression. Interaction was evaluated by attributable proportions (AP), with 95% confidence intervals (CI).ResultsA functional haplotype of the three fully correlated nonsynonymous SNPs in PADI4 was significantly associated with susceptibility to not only anti-CCP-positive (adjusted OR 1.73, 95% CI 1.34 to 2.23) but also -negative RA (adjusted OR 1.75, 95% CI 1.15 to 2.68). A strong association with both non-erosive (adjusted OR 1.62, 95% CI 1.29 to 2.05) and erosive RA (adjusted OR 1.62, 95% CI 1.14 to 2.31) was observed for PADI4 haplotype. Gene-gene interactions between the homozygous RA-risk PADI4 haplotype and SE alleles were significant in both anti-CCP-positive (AP 0.45, 95% CI 0.20 to 0.71) and -negative RA (AP 0.61, 95% CI 0.29 to 0.92). Theses interactions were also observed for both non-erosive (AP 0.48, 95% CI 0.25 to 0.72) and erosive RA (AP 0.46, 95% CI 0.14 to 0.78). In contrast, no interaction was observed between smoking and PADI4 polymorphisms.ConclusionsA haplotype of nonsynonymous SNPs in PADI4 contributes to development of RA regardless of anti-CCP or erosive joint status. The homozygous PADI4 haplotype contribution is affected by gene-gene interactions with HLA-DRB1 SE alleles.

Association of the PADI4 gene polymorphism and HLA-DRB1 shared epitope alleles with rheumatoid arthritis

To investigate the association of single nucleotide polymorphisms (SNPs) of the peptidylarginine deiminase IV (PADI4) and HLA-DRB1 shared epitope (SE) alleles with rheumatoid arthritis(RA) in a Chinese population. Four exonic SNPs of the PADI4 gene (PADI 4_89*A/G, PADI 4_90*C/T, PADI 4_92*C/G and PADI 4_104*C/T) were genotyped in 67 unrelated patients with RA and 81 healthy controls, using cDNA sequencing and T vector cloning. HLA-DRB 1*01, *04 and *10 subtypes were determined by polymerase chain reaction with sequence specific primers (PCR-SSP). The distributions of the 4 SNPs were different in the two groups, and increased RA susceptibility was significantly associated with the minor alleles of PADI 4_89*G (P was 0.023), PADI 4_90*T (P was 0.004), PADI 4_104*T (P was 0.003), and the haplotypes carrying the 4 minor alleles (P was 0.008). HLA-DRB1 SE alleles are composed of HLA-DRB 1*0101, *0102, *0401, *0404, *0405, *0408, *0409, *0410 and *1001. Individuals carrying the SE alleles were associated with increased RA susceptibility (P was 0.002). Individuals carrying both the SE alleles and minor alleles of the 4 SNPs were more susceptible to RA than individuals carrying neither the minor SNP alleles nor the SE alleles. The PADI4 SNPs and haplotypes are associated with RA susceptibility in Chinese. HLA-DRB1 shared epitope is also an important risky factor for RA. There may exist certain synergistic effect between the PADI4 minor alleles and the HLA-DRB1 shared epitope.

Association of Anti–Cyclic citrullinated peptide antibody levels with PADI4 haplotypes in early rheumatoid arthritis and with shared epitope alleles in very late rheumatoid arthritis

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are rheumatoid arthritis (RA)-specific serologic markers. RA susceptibility has been associated with HLA-DRB1 shared epitope (SE) alleles and single-nucleotide polymorphism (SNP) haplotypes in the peptidyl arginine deiminase 4 gene (PADI4). This study was undertaken to determine whether anti-CCP levels are associated with PADI4 haplotypes and/or SE alleles in Korean patients with RA. Three nonsynonymous SNPs in PADI4 (padi4_89, padi4_90, and padi4_92) and SE alleles were genotyped, and serum anti-CCP levels were measured, in 311 patients with nonerosive or erosive RA. The relationships between anti-CCP levels and PADI4 haplotypes and/or SE alleles were analyzed statistically. Anti-CCP levels were significantly higher in patients carrying the PADI4 RA risk haplotype than in patients who did not have the risk haplotype, among anti-CCP-positive patients with RA with a disease duration of <or=34 months (P = 0.041), but not among patients with a longer disease duration or among those who had erosive RA versus nonerosive RA. In contrast, the levels were significantly higher in SE carriers than in noncarriers among patients with RA with a disease duration of >or=141 months (P = 0.0037) and among those who had erosive RA (P = 0.000098), but not among patients who had a shorter disease duration or those who had nonerosive RA. The PADI4 RA risk haplotype is associated with increased anti-CCP levels in RA patients with disease of short duration, and PADI4 may play a role in early RA. In contrast, SE alleles are associated with increased anti-CCP levels in RA patients with very longstanding disease and in patients with erosive RA, suggesting that SE alleles play a role in very late RA.

The functional haplotype of peptidylarginine deiminase IV (S55G, A82V and A112G) associated with susceptibility to rheumatoid arthritis dominates apoptosis of acute T leukemia Jurkat cells

Peptidylarginine deiminase IV (PADI4) posttranslationally converts peptidylarginine to citrulline. It plays an essential role in immune cell differentiation and apoptosis. A haplotype of single-nucleotide polymorphisms (SNPs) in PADI4 is functionally relevant as a rheumatoid arthritis (RA) gene. It could increase enzyme activity leading to raised levels of citrullinated protein and stimulating autoantibody. Previously, our study showed that inducible PADI4 causes haematopoietic cell death. Herein, we further investigate whether RA risk PADI4 haplotype (SNP PADI4; S55G, A82V and A112G) and the increase of its enzymatic activity induce apoptosis. In the tetracycline (Tet)-On Jurkat T cells, ionomycin (Ion) only treatment didn't induce apoptosis however it promoted inducible PADI4-decreased cell viability and -enhanced apoptosis. Through in vitro and in vivo PADI enzyme activity assay, we demonstrated that PADI4 enzyme activity of SNP PADI4 was higher than RA non-risk PADI4 haplotype (WT PADI4). The effect of SNP PADI4-induced apoptosis was superior to WT PADI4. In addition, both Ion and SNP PADI4 synergistically provoked apoptosis were compared with both Ion and WT PADI4. Concurrently, in the conditionally inducible SNP PADI4 cells of Ion treatment-induced apoptosis, not only the expression of Bcl-xL was down-regulated and Bax up-regulated, but also cytochrome c was released from mitochondria to cytoplasm in significant amounts. Western blotting data showed the increase in apoptosomal caspase activation during programmed cell death in the inducible SNP PADI4 cells subsequent to Ion treatment. These data demonstrated that both SNP PADI4 increasing their enzyme activity could enhance apoptosis through the mitochondrial pathway and further provide a conceivable explanation in the pathogenesis of RA following the upregulation of PADI4 activity in its SNPs.

Functional haplotypes of PADI4, encoding citrullinating enzyme peptidylarginine deiminase 4, are associated with rheumatoid arthritis.

Individuals with rheumatoid arthritis frequently have autoantibodies to citrullinated peptides, suggesting the involvement of the peptidylarginine deiminases citrullinating enzymes (encoded by PADI genes) in rheumatoid arthritis. Previous linkage studies have shown that a susceptibility locus for rheumatoid arthritis includes four PADI genes but did not establish which PADI gene confers susceptibility to rheumatoid arthritis. We used a case-control linkage disequilibrium study to show that PADI type 4 is a susceptibility locus for rheumatoid arthritis (P = 0.000008). PADI4 was expressed in hematological and rheumatoid arthritis synovial tissues. We also identified a haplotype of PADI4 associated with susceptibility to rheumatoid arthritis that affected stability of transcripts and was associated with levels of antibody to citrullinated peptide in sera from individuals with rheumatoid arthritis. Our results imply that the PADI4 haplotype associated with susceptibility to rheumatoid arthritis increases production of citrullinated peptides acting as autoantigens, resulting in heightened risk of developing the disease.