Limits...
Myelin basic protein as a novel genetic risk factor in rheumatoid arthritis--a genome-wide study combined with immunological analyses.

Terao C, Ohmura K, Katayama M, Takahashi M, Kokubo M, Diop G, Toda Y, Yamamoto N, Human Disease Genomics Working GroupRheumatoid Arthritis (RA) Clinical and Genetic Study ConsortiumShinkura R, Shimizu M, Gut I, Heath S, Melchers I, Manabe T, Lathrop M, Mimori T, Yamada R, Matsuda F - PLoS ONE (2011)

Bottom Line: The transcription of MBP was significantly elevated with the risk allele compared to the alternative allele (p<0.001).We also established by immunohistochemistry that MBP was expressed in the synovial lining layer of RA patients, the main target of inflammation in the disease.This is the first report of a genetic study in RA implicating MBP as a potential autoantigen and its involvement in pathogenesis of the disease.

View Article: PubMed Central - PubMed

Affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

ABSTRACT
Rheumatoid arthritis (RA) is a major cause of adult chronic inflammatory arthritis and a typical complex trait. Although several genetic determinants have been identified, they account for only a part of the genetic susceptibility. We conducted a genome-wide association study of RA in Japanese using 225,079 SNPs genotyped in 990 cases and 1,236 controls from two independent collections (658 cases and 934 controls in collection1; 332 cases and 302 controls in collection2), followed by replication studies in two additional collections (874 cases and 855 controls in collection3; 1,264 cases and 948 controls in collection4). SNPs showing p<0.005 in the first two collections and p<10(-4) by meta-analysis were further genotyped in the latter two collections. A novel risk variant, rs2000811, in intron2 of the myelin basic protein (MBP) at chromosome 18q23 showed strong association with RA (p = 2.7×10(-8), OR 1.23, 95% CI: 1.14-1.32). The transcription of MBP was significantly elevated with the risk allele compared to the alternative allele (p<0.001). We also established by immunohistochemistry that MBP was expressed in the synovial lining layer of RA patients, the main target of inflammation in the disease. Circulating autoantibody against MBP derived from human brain was quantified by ELISA between patients with RA, other connective tissue diseases and healthy controls. As a result, the titer of anti-MBP antibody was markedly higher in plasma of RA patients compared to healthy controls (p<0.001) and patients with other connective tissue disorders (p<0.001). ELISA experiment using citrullinated recombinant MBP revealed that a large fraction of anti-MBP antibody in RA patients recognized citrullinated MBP. This is the first report of a genetic study in RA implicating MBP as a potential autoantigen and its involvement in pathogenesis of the disease.

Show MeSH

Related in: MedlinePlus

Quantification of circulating antibodies against MBP protein.A. Each boxplot indicates distribution of anti-MBP antibody titers in healthy controls, in RA patients, and in other connective tissue diseases (CTDs) (for detailed composition of the disease patients, see materials and methods). Results were representative of the two independent experiments. *** indicates statistical p-value smaller than 0.001. B. Correlation of autoantibody levels between human brain-derived MBP and recombinant MBP (rMBP). C. Correlation of autoantibody levels between human brain-derived MBP and citrullinated rMBP. Sixty RA patients who were positive for anti-MBP antibody were used for the analysis. In each figure, antibody titers were shown as arbitrary unit (AU).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3108877&req=5

pone-0020457-g004: Quantification of circulating antibodies against MBP protein.A. Each boxplot indicates distribution of anti-MBP antibody titers in healthy controls, in RA patients, and in other connective tissue diseases (CTDs) (for detailed composition of the disease patients, see materials and methods). Results were representative of the two independent experiments. *** indicates statistical p-value smaller than 0.001. B. Correlation of autoantibody levels between human brain-derived MBP and recombinant MBP (rMBP). C. Correlation of autoantibody levels between human brain-derived MBP and citrullinated rMBP. Sixty RA patients who were positive for anti-MBP antibody were used for the analysis. In each figure, antibody titers were shown as arbitrary unit (AU).

Mentions: Antibodies to MBP are the major component of autoantibodies in multiple sclerosis, a human autoimmunity with a neurodegenerative phenotype [29]. To assess a possible association of circulating antibodies to MBP with RA, we quantified these in plasma from 323 RA cases, 131 healthy controls and 162 patients with other connective tissue diseases (disease controls) by Enzyme-linked immunosorbent assay (ELISA) with MBP purified from human brain as antigen. The average levels of anti-MBP antibody in plasma of RA patients were much higher than those of healthy controls and patients with seven other connective tissue diseases (p<0.001; Figure 4A). Specificity in detection of anti-MBP antibody in ELISA experiments was confirmed by immunoblotting using plasma of a subset of RA patients and controls (Figure S5, Method S3). We also confirmed that the enhancement of ELISA signals by non-specific binding of IgG- and IgM-RF in patients' sera was negligible (for details, see Method S4 and Figure S6).


Myelin basic protein as a novel genetic risk factor in rheumatoid arthritis--a genome-wide study combined with immunological analyses.

Terao C, Ohmura K, Katayama M, Takahashi M, Kokubo M, Diop G, Toda Y, Yamamoto N, Human Disease Genomics Working GroupRheumatoid Arthritis (RA) Clinical and Genetic Study ConsortiumShinkura R, Shimizu M, Gut I, Heath S, Melchers I, Manabe T, Lathrop M, Mimori T, Yamada R, Matsuda F - PLoS ONE (2011)

Quantification of circulating antibodies against MBP protein.A. Each boxplot indicates distribution of anti-MBP antibody titers in healthy controls, in RA patients, and in other connective tissue diseases (CTDs) (for detailed composition of the disease patients, see materials and methods). Results were representative of the two independent experiments. *** indicates statistical p-value smaller than 0.001. B. Correlation of autoantibody levels between human brain-derived MBP and recombinant MBP (rMBP). C. Correlation of autoantibody levels between human brain-derived MBP and citrullinated rMBP. Sixty RA patients who were positive for anti-MBP antibody were used for the analysis. In each figure, antibody titers were shown as arbitrary unit (AU).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108877&req=5

pone-0020457-g004: Quantification of circulating antibodies against MBP protein.A. Each boxplot indicates distribution of anti-MBP antibody titers in healthy controls, in RA patients, and in other connective tissue diseases (CTDs) (for detailed composition of the disease patients, see materials and methods). Results were representative of the two independent experiments. *** indicates statistical p-value smaller than 0.001. B. Correlation of autoantibody levels between human brain-derived MBP and recombinant MBP (rMBP). C. Correlation of autoantibody levels between human brain-derived MBP and citrullinated rMBP. Sixty RA patients who were positive for anti-MBP antibody were used for the analysis. In each figure, antibody titers were shown as arbitrary unit (AU).
Mentions: Antibodies to MBP are the major component of autoantibodies in multiple sclerosis, a human autoimmunity with a neurodegenerative phenotype [29]. To assess a possible association of circulating antibodies to MBP with RA, we quantified these in plasma from 323 RA cases, 131 healthy controls and 162 patients with other connective tissue diseases (disease controls) by Enzyme-linked immunosorbent assay (ELISA) with MBP purified from human brain as antigen. The average levels of anti-MBP antibody in plasma of RA patients were much higher than those of healthy controls and patients with seven other connective tissue diseases (p<0.001; Figure 4A). Specificity in detection of anti-MBP antibody in ELISA experiments was confirmed by immunoblotting using plasma of a subset of RA patients and controls (Figure S5, Method S3). We also confirmed that the enhancement of ELISA signals by non-specific binding of IgG- and IgM-RF in patients' sera was negligible (for details, see Method S4 and Figure S6).

Bottom Line: The transcription of MBP was significantly elevated with the risk allele compared to the alternative allele (p<0.001).We also established by immunohistochemistry that MBP was expressed in the synovial lining layer of RA patients, the main target of inflammation in the disease.This is the first report of a genetic study in RA implicating MBP as a potential autoantigen and its involvement in pathogenesis of the disease.

View Article: PubMed Central - PubMed

Affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

ABSTRACT
Rheumatoid arthritis (RA) is a major cause of adult chronic inflammatory arthritis and a typical complex trait. Although several genetic determinants have been identified, they account for only a part of the genetic susceptibility. We conducted a genome-wide association study of RA in Japanese using 225,079 SNPs genotyped in 990 cases and 1,236 controls from two independent collections (658 cases and 934 controls in collection1; 332 cases and 302 controls in collection2), followed by replication studies in two additional collections (874 cases and 855 controls in collection3; 1,264 cases and 948 controls in collection4). SNPs showing p<0.005 in the first two collections and p<10(-4) by meta-analysis were further genotyped in the latter two collections. A novel risk variant, rs2000811, in intron2 of the myelin basic protein (MBP) at chromosome 18q23 showed strong association with RA (p = 2.7×10(-8), OR 1.23, 95% CI: 1.14-1.32). The transcription of MBP was significantly elevated with the risk allele compared to the alternative allele (p<0.001). We also established by immunohistochemistry that MBP was expressed in the synovial lining layer of RA patients, the main target of inflammation in the disease. Circulating autoantibody against MBP derived from human brain was quantified by ELISA between patients with RA, other connective tissue diseases and healthy controls. As a result, the titer of anti-MBP antibody was markedly higher in plasma of RA patients compared to healthy controls (p<0.001) and patients with other connective tissue disorders (p<0.001). ELISA experiment using citrullinated recombinant MBP revealed that a large fraction of anti-MBP antibody in RA patients recognized citrullinated MBP. This is the first report of a genetic study in RA implicating MBP as a potential autoantigen and its involvement in pathogenesis of the disease.

Show MeSH
Related in: MedlinePlus