Matrix metalloproteinases (MMPs), also called matrixins, function in the extracellular environment of cells and degrade both matrix and non-matrix proteins. They play central roles in morphogenesis, wound healing, tissue repair and remodelling in response to injury, e.g. after myocardial infarction, and in progression of diseases such as atheroma, arthritis, cancer and chronic tissue ulcers. They are multi-domain proteins and their activities are regulated by tissue inhibitors of metalloproteinases (TIMPs). This review introduces the members of the MMP family and discusses their domain structure and function, proenyme activation, the mechanism of inhibition by TIMPs and their significance in physiology and pathology.

Structure and function of matrix metalloproteinases and TIMPs

Application of the experimental design of genome-wide association studies (GWASs) is now 10 years old (young), and here we review the remarkable range of discoveries it has facilitated in population and complex-trait genetics, the biology of diseases, and translation toward new therapeutics. We predict the likely discoveries in the next 10 years, when GWASs will be based on millions of samples with array data imputed to a large fully sequenced reference panel and on hundreds of thousands of samples with whole-genome sequencing data.

10 Years of GWAS Discovery: Biology, Function, and Translation

An Expanded View of Complex Traits: From Polygenic to Omnigenic

Recent work has demonstrated that some functional categories of the genome contribute disproportionately to the heritability of complex diseases. Here we analyze a broad set of functional elements, including cell type-specific elements, to estimate their polygenic contributions to heritability in genome-wide association studies (GWAS) of 17 complex diseases and traits with an average sample size of 73,599. To enable this analysis, we introduce a new method, stratified LD score regression, for partitioning heritability from GWAS summary statistics while accounting for linked markers. This new method is computationally tractable at very large sample sizes and leverages genome-wide information. Our findings include a large enrichment of heritability in conserved regions across many traits, a very large immunological disease-specific enrichment of heritability in FANTOM5 enhancers and many cell type-specific enrichments, including significant enrichment of central nervous system cell types in the heritability of body mass index, age at menarche, educational attainment and smoking behavior.

/pdf/partitioning-heritability-by-functional-annotation-using-13dk84e4b8.pdf

Partitioning heritability by functional annotation using genome-wide association summary statistics.

A major challenge in human genetics is to devise a systematic strategy to integrate disease-associated variants with diverse genomic and biological data sets to provide insight into disease pathogenesis and guide drug discovery for complex traits such as rheumatoid arthritis (RA)1. Here we performed a genome-wide association study meta-analysis in a total of >100,000 subjects of European and Asian ancestries (29,880 RA cases and 73,758 controls), by evaluating ~10 million single-nucleotide polymorphisms. We discovered 42 novel RA risk loci at a genome-wide level of significance, bringing the total to 101 (refs 2, 3, 4). We devised an in silico pipeline using established bioinformatics methods based on functional annotation5, cis-acting expression quantitative trait loci6 and pathway analyses7, 8, 9—as well as novel methods based on genetic overlap with human primary immunodeficiency, haematological cancer somatic mutations and knockout mouse phenotypes—to identify 98 biological candidate genes at these 101 risk loci. We demonstrate that these genes are the targets of approved therapies for RA, and further suggest that drugs approved for other indications may be repurposed for the treatment of RA. Together, this comprehensive genetic study sheds light on fundamental genes, pathways and cell types that contribute to RA pathogenesis, and provides empirical evidence that the genetics of RA can provide important information for drug discovery.

/pdf/genetics-of-rheumatoid-arthritis-contributes-to-biology-and-4wuv6x8yle.pdf

Genetics of rheumatoid arthritis contributes to biology and drug discovery

[Immunological and serological tests for diagnosis of rheumatoid arthritis: MMP-3].

Background As treatments for rheumatoid arthritis (RA) such as methotrexate (MTX) and biological agents have made dramatic progress in this decade, it is desirable to improve patient quality of life and prognosis, including management of various comorbidities. Malignancy is an important comorbidity in patients with RA1,2. No significant difference in the overall incidence of malignancies in Japanese patients with RA (standardized incidence ratio [SIR] 0.96, 95% confidence interval [CI] 0.90–1.03) was noted compared with the general Japanese population3. However, a markedly significant increase in the incidence of malignant lymphoma was observed (SIR 5.10, 95% CI 4.21–6.13), and the incidence of lung cancer in males was also increased significantly3. In contrast, the incidence of gastric cancer and colorectal cancer was decreased significantly3. It is important to investigate the risk factors for malignancies to examine the prognosis of patients with RA. Objectives To investigate the risk factors for overall and site-specific malignancies in a large observational cohort of Japanese patients with RA over a long-term period. Methods Among Japanese patients with RA enrolled in the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort from April 2000 to September 2013, all malignancies were extracted from patients9 self-reporting and confirmed by medical records. Patients who dropped out of the IORRA cohort were asked about comorbidities, including malignancies, by follow-up mail. With regard to overall malignancies and malignancies at frequently involved sites (lung cancer, malignant lymphoma, breast cancer, gastric cancer and colorectal cancer), risk factors were analysed with time-dependent Cox regression adjusted by age, gender, smoking history and BMI. Results Among 11,106 Japanese patients with RA representing 122,706 person-years, a total of 830 overall malignancies, including 114 lung cancers, 114 malignant lymphomas, 105 breast cancers, 95 gastric cancers and 90 colorectal cancers, were confirmed. RA disease duration was a significant risk factor for lung cancer (hazard ratio [HR] 0.95, P =0.001) and malignant lymphoma (HR 0.95, P =0.004). RF positivity was a significant risk factor for lung cancer (HR 2.26, P =0.018). DAS28 score was a significant risk factor for overall malignancies (HR 1.10, P =0.008), lung cancer (HR 1.25, P =0.012) and malignant lymphoma (HR 1.22, P =0.049). Neither MTX nor biological agent use was a significant risk factor for overall malignancies or malignancies at specific sites. Conclusions Higher disease activity was a risk factor for overall malignancies, lung cancer and malignant lymphoma in Japanese patients with RA. However, treatment with MTX and biological agents was not a risk factor for malignancy. These results suggest that tight control of RA disease activity would protect against the occurrence of malignancies in patients with RA. References Gullick NJ, et al. Best Pract Res Clin Rheumatol. 2011;25:469–83. Nakajima A, et al. Scand J Rheumatol. 2010;39:360–7. Sugimoto N, et al. EULAR Congress 2015;THU0161. Disclosure of Interest N. Sugimoto: None declared, E. Tanaka Speakers bureau: ET has received speaker fees or consulting fees from Abbvie, Eisai Pharmaceutical, Chugai Pharmaceutical, Bristol Myers Squibb, Astellas Pharmaceutical, Pfizer, Takeda Pharmaceutical, and Santen Pharmaceutical., E. Inoue: None declared, Y. Shimizu: None declared, K. Shidara: None declared, A. Nakajima: None declared, A. Taniguchi: None declared, S. Momohara Speakers bureau: SM has received speaker fees from Abbott, AbbVie, Astellas, Bristol-Myers Squibb, Chugai, Eisai, Mitsubishi Tanabe, Pfizer, Takeda, and Teijin., H. Yamanaka Speakers bureau: HY has received speaker fees from Abbott, AbbVie, Asahikasei, Astellas, AstraZeneca, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taishotoyama, Takeda, and Teijin.

FRI0143 Risk Factors for Malignancy in Japanese Patients with Rheumatoid Arthritis Based on The IORRA Cohort during A 14-Year Observation Period

Rheumatoid arthritis (RA) is a complex polygenic disease characterized by progressive joint destruction. Anti-citrullinated peptide antibody (ACPA) is the most specific autoantibody for RA. Genetic polymorphisms in the PADI4 gene, encoding citrullinating enzyme peptidylarginine deiminase 4 (PADI4), have been associated with susceptibility to RA [1,2]. They have also been reported to be associated with radiographic joint destruction in patients with RA [3,4]. We focused on ACPA-negative RA patients to investigate whether a PADI4 polymorphism is associated with joint damage in ACPA-negative patients.

DNA samples from 122 Japanese ACPA-negative RA patients were used for the study; 81.1% were female, 51.6% were rheumatoid factor (RF)-positive, and the mean age was 55 years. Sharp/van der Heijde score of the hands at a 5-year disease duration, which represents joint damage, was scored and log-transformed as described elsewhere [4]. Single-nucleotide polymorphism (SNP) rs2240340 was selected and genotyped by using a TaqMan method as described elsewhere [4]. The genetic risk of joint damage associated with rs2240340 was assessed by multiple regression analysis adjusted for HLA-DRB1 shared-epitope alleles and RF that are thought to be associated with joint damage in patients with RA [4].

The PADI4 SNP was significantly associated with radiographic joint destruction in the ACPA-negative RA patients in a recessive model (P = 0.0287) (Table 1 and Figure 1). The overall genotyping success rate was 99.2% and the genotype concordance rate was 100% as assessed by duplicate samples. Although the sample size is one of the major limitations to the study of ACPA-negative patients because of the high positivity of ACPA (up to 90%) in RA populations, we were able to collect DNA samples from 122 ACPA-negative RA patients with radiographic data.



Table 1

Association of PADI4 SNP (recessive model) with Sharp/van der Heijde score of hands at 5-year disease duration in ACPA-negative RA patients 





Figure 1

Boxplots representing the distribution of Sharp/van der Heijde score of hands at 5-year disease duration according to the number of the susceptibility allele of rs2240340 (minor allele, A) in the PADI4 locus. Each box represents the interquartile range ...



PADI4 encodes citrullinating enzymes that may play an important role in ACPA formation. It has been shown that PADI4 alleles were associated with the presence of ACPA in patients with RA [1]. In the present study, we have shown that PADI4 polymorphism contributes to joint destruction in ACPA-negative RA patients. A recent study has suggested that PADI4 gene contributes to the development of RA, regardless of ACPA status [3]. We have also reported that the PADI4 risk allele has an impact on joint damage after adjustment for ACPA status [4]. The PADI4 gene is likely to play a role in the disease progression of RA in addition to its role in ACPA formation. The results of this study provide important knowledge of the risks on progressive joint damage in patients with RA.

/pdf/response-to-peptidyl-arginine-deiminase-type-iv-padi4-51mn2oerrv.pdf

Response to ‘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’

Background Rheumatoid arthritis (RA) is characterized by chronic inflammation and joint destruction, resulting in deteriorated physical function. Genetic predisposition factors associated with the susceptibility to RA and the severity of joint destruction have been reported so far. 1,2 However, risk loci for progression of functional disability remain poorly understood. The Health Assessment Questionnaire (HAQ) score is considered as the main and good functional outcome measure in RA. We used the Japanese version of HAQ (J-HAQ) score change in five years and investigated whether 22 established susceptibility genes for RA 1 were associated with progression of functional disability in Japanese patients with RA. Objectives The purpose of this study was to find the genetic factors associated with progression of functional disability in Japanese patients with RA. Methods This study included 1384 Japanese patients with RA, who participated in the Institute of Rheumatology Rheumatoid Arthritis cohort study (IORRA) from 2000 to 2004, and from whom the J-HAQ score was obtained at the enrollment in IORRA and five years later. The J-HAQ score change was calculated as the value in 5 years minus the one at the enrollment. HLA-DRB1 shared epitope (SE) and 21 single nucleotide polymorphisms (SNPs) reported in the recent genome-wide association study meta-analysis 1 were selected and genotyped in the DNA samples: rs2240340 (PADI4), rs2230926 (TNFAIP3), rs3093024 (CCR6), rs11900673 (B3GNT2), rs2867461 (ANXA3), rs657075 (CSF2), rs12529514 (CD83), rs2233434 (NFKBIE), rs10821944 (ARID5B), rs3781913 (PDE2A-ARAP1), rs2841277 (PLD4), rs2847297 (PTPN2), rs2075876 (AIRE), rs3890745 (TNFRSF14), rs7528684 (FCRL3), rs934734 (SPRED2), rs1160542 (AFF3), rs7574865 (STAT4), rs231775 (CTLA4), rs729302 (IRF5) and rs13277113 (BLK). Multivariate linear regression analyses were performed in order to examine the association of HLA-DRB1 SE and each SNP with the J-HAQ score change. Adjustments were made for non-genetic factors associated with the J-HAQ score change. They had been determined by univariate linear regression analyses. Results Univariate linear regression analyses showed that gender, age at the enrollment, disease duration, year of the enrollment, anti-citrullinated peptide antibody status and the J-HAQ score at the enrollment were significantly associated with the J-HAQ score change. Multivariate linear regression analyses revealed that the minor allele of rs7574865 (STAT4) was associated with an increase of the J-HAQ score in five years ( P =0.046). However, the association was not significant after Bonferroni correction for multiple comparisons. The other genes showed no association. Conclusions Our results indicated that rs7574865 (STAT4) might be a risk factor for progression of functional disability, but the association could not reach the level of the significance. Further studies would be required to confirm the association. References Okada Y, et al. Meta-analysis identifies nine new loci associated with rheumatoid arthritis in the Japanese population. Nat genet. 2012 Mar 25;44(5):511-6. Suzuki T, et al. PADI4 and HLA-DRB1 are genetic risks for radiographic progression in RA patients, independent of ACPA status: results from IORRA cohort study. PLoS One. 2013;8(4):e61045. doi: 10.1371/journal.pone.0061045. Epub 2013 Apr 8. Acknowledgements We thank all DNA donors for making this study possible. We appreciate all the members of Institute of Rheumatology, Tokyo Women9s Medical University for their effort on the IORRA cohort. We are also grateful to Ms Kaori Arai for her technical assistance. Disclosure of Interest : A. Mizuno: None declared, S. Yoshida: None declared, K. Ikari Grant/research support: Pfizer Japan Inc., Takeda Pharmaceutical Co. Ltd., Speakers bureau: Abbvie Japan Co.,Ltd., Asahikasei Pharma Corporation, Astellas Pharma Inc., Eisai Co.,Ltd., Kaken Pharmaceutical Co.,Ltd., Mitsubishi Tanabe Pharma Corporation, Taishotoyama Pharmaceutical Co.,Ltd., Y. Toyama: None declared, A. Taniguchi: None declared, H. Yamanaka Grant/research support: Abbott, AbbVie, Asahikasei, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taishotoyama, Takeda, Teijin, Consultant for: Abbott, AbbVie, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, Mitsubishi Tanabe, Nippon Kayaku, Pfizer, Takeda, Teijin., Speakers bureau: Abbott, AbbVie, Astellas, Bristol-Myers Squib, Chugai, Eisai, Mitsubishi Tanabe, Pfizer, Takeda, Teijin., S. Momohara: None declared DOI 10.1136/annrheumdis-2014-eular.3107

THU0458 Analysis of Genetic Factors Associated with Progression of Functional Disability in Japanese Patients with Rheumatoid Arthritis

Background Indirect costs of rheumatoid arthritis (RA) due to losses such as reduced productivity are an important social issue in addition to rapidly increasing direct costs; however, indirect costs have not been thoroughly assessed in Japan. With the recent changes in socioeconomic structure, the number of female paid workers has been increasing; thus, the impact of RA on the work impairment of Japanese patients has been rapidly increasing. Furthermore, work status is strongly influenced by cultural differences among races. Longitudinal analyses of factors contributing to the worsening of work impairment should be conducted in patients with RA in real-world settings. Objectives To identify factors contributing to early worsening of absenteeism in patients with RA in daily practice. Methods The study population consisted of patients with RA who were working for pay and who participated in the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort study in 2012 to 2013, had an absenteeism score of 0 as determined by the Work Productivity and Activity Impairment (WPAI) questionnaire at baseline, and could be followed up for WPAI assessments for at least 6 months to a maximum of 18 months. The time to 10% or more absenteeism (percent work time missed due to RA) was the primary outcome. A Cox regression analysis was used to identify factors contributing to the worsening of absenteeism. Results The study included 1,941 patients with RA (mean age, 50.6 years; RA duration, 10.8 years; females, 79.3%; DAS28, 2.6; Japanese version of the Health Assessment Questionnaire [J-HAQ], 0.32). Absenteeism first exceeded 10% at 6, 12 and 18 months in 47 (cumulative probability of worsening: 2.4% [95% CI: 1.7%>3.1%]), 33 (4.5% [95% CI: 3.5%>5.4%]) and 20 (6.2% [95% CI: 5.0%>7.4%]) patients, respectively. Results of a multivariate Cox regression analysis showed that lower EQ-5D scores at baseline (p=0.01) and steroid dosage at baseline (p=0.01) were significantly associated with earlier worsening of absenteeism, and that the use of biologics did not have a significant impact (p=0.46). Conclusions Factors contributing to earlier worsening of absenteeism were identified in patients with RA in daily practice. The results suggest that preventing quality of life deterioration without steroid use might be important in stopping the progression of work impairment. Disclosure of Interest E. Tanaka: None declared, E. Inoue: None declared, R. Yamaguchi: None declared, Y. Shimizu: None declared, N. Sugimoto: None declared, D. Hoshi: None declared, K. Shidara: None declared, E. Sato: None declared, Y. Seto: None declared, A. Nakajima: None declared, S. Momohara Consultant for: AbbVie, Bristol-Myers-Squibb, Eisai, Mitsubishi-Tanabe, and Takeda., A. Taniguchi Grant/research support from: Takeda., Consultant for: AbbVie, Eisai, Mitsubishi-Tanabe, and Teijin., H. Yamanaka Grant/research support from: AbbVie, Asahikasei Pharma, Astellas, Bristol-Myers-Squibb, Chugai, Daiichi-Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi-Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taisho-Toyama, Takeda, and Teijin Pharma., Consultant for: Teijin Pharma, Chugai, Astellas, Bristol-Meyers, AbbVie, Daiichi-Sankyo, Nihon-Kayaku, Mitsubishi-Tanabe, Pfizer, Takeda, and UCB.

https://ard.bmj.com/content/annrheumdis/74/Suppl_2/672.3.full.pdf

Shigeki Momohara

Papers

[Immunological and serological tests for diagnosis of rheumatoid arthritis: MMP-3].

FRI0143 Risk Factors for Malignancy in Japanese Patients with Rheumatoid Arthritis Based on The IORRA Cohort during A 14-Year Observation Period

Response to ‘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’

THU0458 Analysis of Genetic Factors Associated with Progression of Functional Disability in Japanese Patients with Rheumatoid Arthritis

SAT0068 A Longitudinal Study of Factors Contributing to the Worsening of Absenteeism in Patients with Rheumatoid Arthritis Based on the Iorra Cohort