R. van der Breggen

A Genome-Wide Association Study Identifies an Osteoarthritis Susceptibility Locus on Chromosome 7q22

OBJECTIVE To identify novel genes involved in osteoarthritis (OA), by means of a genome-wide association study. METHODS We tested 500,510 single-nucleotide polymorphisms (SNPs) in 1,341 Dutch Caucasian OA cases and 3,496 Dutch Caucasian controls. SNPs associated with at least 2 OA phenotypes were analyzed in 14,938 OA cases and approximately 39,000 controls. Meta-analyses were performed using the program Comprehensive Meta-analysis, with P values <1 x 10(-7) considered genome-wide significant. RESULTS The C allele of rs3815148 on chromosome 7q22 (minor allele frequency 23%; intron 12 of the COG5 gene) was associated with a 1.14-fold increased risk (95% confidence interval 1.09-1.19) of knee and/or hand OA (P = 8 x 10(-8)) and also with a 30% increased risk of knee OA progression (95% confidence interval 1.03-1.64) (P = 0.03). This SNP is in almost complete linkage disequilibrium with rs3757713 (68 kb upstream of GPR22), which is associated with GPR22 expression levels in lymphoblast cell lines (P = 4 x 10(-12)). Immunohistochemistry experiments revealed that G protein-coupled receptor protein 22 (GPR22) was absent in normal mouse articular cartilage or synovium. However, GPR22-positive chondrocytes were found in the upper layers of the articular cartilage of mouse knee joints that were challenged with in vivo papain treatment or methylated bovine serum albumin treatment. GPR22-positive chondrocyte-like cells were also found in osteophytes in instability-induced OA. CONCLUSION Our findings identify a novel common variant on chromosome 7q22 that influences susceptibility to prevalence and progression of OA. Since the GPR22 gene encodes a G protein-coupled receptor, this is potentially an interesting therapeutic target.

Knee and hip articular cartilage have distinct epigenomic landscapes: implications for future cartilage regeneration approaches

Objectives To elucidate the functional epigenomic landscape of articular cartilage in osteoarthritis (OA) affected knee and hip joints in relation to gene expression. Methods Using Illumina Infinium HumanMethylation450 BeadChip arrays, genome-wide DNA methylation was measured in 31 preserved and lesioned cartilage sample pairs (14 knees and 17 hips) from patients who underwent a total joint replacement due to primary OA. Using previously published genome-wide expression data of 33 pairs of cartilage samples, of which 13 pairs were overlapping with the current methylation dataset, we assessed gene expression differences in differentially methylated regions (DMRs). Results Principal component analysis of the methylation data revealed distinct clustering of knee and hip samples, irrespective of OA pathophysiology. A total of 6272 CpG dinucleotides were differentially methylated between the two joints, comprising a total of 357 DMRs containing 1817 CpGs and 245 unique genes. Enrichment analysis of genes proximal of the DMRs revealed significant enrichment for developmental pathways and homeobox (HOX) genes. Subsequent transcriptomic analysis of DMR genes exposed distinct knee and hip expression patterns. Conclusions Our findings reveal consistent DMRs between knee and hip articular cartilage that marked transcriptomic differences among HOX genes, which were not reflecting the temporal sequential HOX expression pattern during development. This implies distinct mechanisms for maintaining cartilage integrity in adulthood, thereby contributing to our understanding of cartilage homeostasis and future tissue regeneration approaches.

Large replication study and meta-analyses of DVWA as an osteoarthritis susceptibility locus in European and Asian populations

Recently, through a genome wide association study in Japanese knee osteoarthritis (OA) cases, a previously unknown gene, DVWA, was identified. The non-synonymous single nucleotide polymorphism (SNP) rs7639618 was subsequently found to be consistent and most significantly associated in Japanese and Han Chinese knee OA studies and functional relevant. Here, the association of the DVWA polymorphisms (rs7639618, rs11718863 and rs9864422) was genotyped in 1120 knee OA cases, 1482 hip OA cases and 2147 controls, all of white European descent from the Netherlands, the UK, Spain and Greece. Random effect DerSimonian and Laird meta-analyses were performed to assess the association in the different strata. To assess a more global effect, the original Japanese and Chinese data were included with the European. The meta-analyses provided evidence for global association of rs7639618 with knee OA with an odds ratio (OR) of 1.29, 95% confidence interval (CI) of 1.15-1.45 and a P-value of 2.70 x 10(-5). This effect, however, showed moderate heterogeneity, and rs7639618 was not independently associated with knee OA in Europeans, with an OR of 1.16, 95% CI of 0.99-1.35 and a P-value of 0.063. Furthermore, no association was observed with hip OA in Europeans, with a P-value of 0.851. Our results suggest that there may be global relevance for the DVWA SNP rs7639618 among knee OA cases, however, the apparent lower effect size in combination with the higher risk allele frequency in the European samples highlights again the ethnic differences in effects of discovered OA susceptibility genes.

Meta-analyses of genes modulating intracellular T3 bio-availability reveal a possible role for the DIO3 gene in osteoarthritis susceptibility

Objective To study whether common genetic variants of the genes involved in the complex regulatory mechanism determining the intracellular bio-availability of T3 influence osteoarthritis onset. Methods In total 17 genetic variants within the genes encoding WD40-repeat/SOCS-box protein 1, ubiquitin specific protease 33, thyroid hormone receptor α, deiodinase, iodothyronine, type III (DIO3) and Indian hedgehog were measured and associated with osteoarthritis in a meta-analyses in European populations from the UK, The Netherlands, Greece and Spain containing a total of 3252 osteoarthritis cases and 2132 controls. Results The minor allele of the DIO3 variant rs945006 showed suggestive evidence for protective association in the overall meta-analyses, which was supported by individual osteoarthritis studies and osteoarthritis subtypes. The association appeared most significant in cases with knee and/or hip with an allelic OR of 0.81 (95% CI 0.70 to 0.930) with a nominal p value of 0.004 and a permutation-based corrected p value for multiple testing of 0.039. Conclusion The findings suggest that the DIO3 gene modulates osteoarthritis disease risk; however, additional studies are necessary to replicate our findings. To elucidate the molecular mechanisms focus should be on the local adaptation to T3 availability either during the endochondral ossification process or during ageing of the articular cartilage.

Abstract 2942: Immunophenotypes in young-onset colorectal cancer

Colorectal cancer accounts for ten percent of new cancer cases and is the fourth most frequent cause of cancer-related deaths worldwide. In recent years, mainly due to screening programs, more patients are diagnosed in early stages of tumor progression, leading to a higher survival rate. However, the incidence of young ( To our knowledge, no study has yet characterized immunophenotypes and immune evasive mechanisms specifically in young-onset colorectal cancers. To that end we have investigated the expression of HLA class I and PD-L1 in over 200 colorectal cancers derived from young-onset ( We describe that HLA class I expression is maintained in the large majority of tumors allowing thus the development of neo-antigen targeted therapies. Interestingly, reduced expression of HLA class I but not total loss was associated with liver metastases, which suggests a specific selective pressure at this organ that might warrant tailored immune therapeutic interventions. As previous studies on colorectal cancer demonstrated, PD-L1 expression is limited and often restricted to immune cell compartments. The presence of immune cell infiltrates was related to the mutation background of tumors but also to their HLA class I phenotype: tumors with altered HLA class I expression were more likely to present traces of lymphocyte-mediated anti-tumor immunity. Retained HLA class I expression in the majority of colorectal cancers associated with low infiltration by effector immune cells suggests the therapeutic induction of anti-tumor immune responses in young-onset colorectal cancers, for instance, by means of neo-antigen-targeted therapies. We are currently assessing the frequency of natural recognition of neo-antigens in an autologous setting in young-onset, late-stage colorectal cancers. This work was supported by the Fight Colorectal Cancer-Michael’s Mission-AACR Fellowship in Young-Onset, Late-Stage Colorectal Cancer Research awarded to N.F.C.C. de Miranda (15-40-1645-DEMI) Citation Format: M E. van Herk, M Lee, M Rytterdahl, M E. Kop, A F. Ramalheiro, R van der Breggen, T van Wezel, H Morreau, E S. Jordanova, N F. de Miranda. Immunophenotypes in young-onset colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2942. doi:10.1158/1538-7445.AM2017-2942

353 GENOME WIDE EXPRESSION ANALYSIS OF OSTEOARTHRITIS AFFECTED AND PRESERVED CARTILAGE FROM JOINT REPLACEMENT SURGERY MATERIAL IN THE RAAK STUDY

352 THE ASSOCIATION OF GENES WITHIN THE VITAMIN D METABOLISM PATHWAY AND RADIOGRAPHIC KNEE OSTEOARTHRITIS: DATA FROM THE OSTEOARTHRITIS INITIATIVE GENOME-WIDE ASSOCIATION STUDY L. Yerges-Armstrong, C. Lu, M.C. Hochberg, B. Mitchell, D. Duggan, R. Jackson, for The OAI Investigators. Univ. of Maryland Sch. of Med., Baltimore, MD, USA; TGEN, Phoenix, AZ, USA; The Ohio State Univ. Sch. of Med., Columbus, OH, USA