Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis.
OBJECTIVE: To examine synovial fluid as a site for generating citrullinated antigens, including the candidate autoantigen citrullinated alpha-enolase, in rheumatoid arthritis (RA). METHODS: Synovial fluid was obtained from 20 patients with RA, 20 patients with spondylarthritides (SpA), and 20 patie...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2008
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| _version_ | 1797066783236030464 |
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| author | Kinloch, A Lundberg, K Wait, R Wegner, N Lim, N Zendman, A Saxne, T Malmström, V Venables, P |
| author_facet | Kinloch, A Lundberg, K Wait, R Wegner, N Lim, N Zendman, A Saxne, T Malmström, V Venables, P |
| author_sort | Kinloch, A |
| collection | OXFORD |
| description | OBJECTIVE: To examine synovial fluid as a site for generating citrullinated antigens, including the candidate autoantigen citrullinated alpha-enolase, in rheumatoid arthritis (RA). METHODS: Synovial fluid was obtained from 20 patients with RA, 20 patients with spondylarthritides (SpA), and 20 patients with osteoarthritis (OA). Samples were resolved using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by staining with Coomassie blue and immunoblotting for citrullinated proteins, alpha-enolase, and the deiminating enzymes peptidylarginine deiminase type 2 (PAD-2) and PAD-4. Proteins from an RA synovial fluid sample were separated by 2-dimensional electrophoresis, and each protein was identified by immunoblotting and mass spectrometry. Antibodies to citrullinated alpha-enolase peptide 1 (CEP-1) and cyclic citrullinated peptide 2 were measured by enzyme-linked immunosorbent assay. RESULTS: Citrullinated polypeptides were detected in the synovial fluid from patients with RA and patients with SpA, but not in OA samples. Alpha-enolase was detected in all of the samples, with mean levels of 6.4 ng/microl in RA samples, 4.3 ng/microl in SpA samples, and <0.9 ng/microl in OA samples. Two-dimensional electrophoresis provided evidence that the alpha-enolase was citrullinated in RA synovial fluid. The citrullinating enzyme PAD-4 was detected in samples from all 3 disease groups. PAD-2 was detected in 18 of the RA samples, in 16 of the SpA samples, and in none of the OA samples. Antibodies to CEP-1 were found in 12 of the RA samples (60%), in none of the SpA samples, and in 1 OA sample. CONCLUSION: These results highlight the importance of synovial fluid for the expression of citrullinated autoantigens in inflammatory arthritis. Whereas the expression of citrullinated proteins is a product of inflammation, the antibody response remains specific for RA. |
| first_indexed | 2024-03-06T21:46:56Z |
| format | Journal article |
| id | oxford-uuid:49e9a4e7-6b96-456e-b5e9-d465fa15087f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:46:56Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | oxford-uuid:49e9a4e7-6b96-456e-b5e9-d465fa15087f2022-03-26T15:34:31ZSynovial fluid is a site of citrullination of autoantigens in inflammatory arthritis.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:49e9a4e7-6b96-456e-b5e9-d465fa15087fEnglishSymplectic Elements at Oxford2008Kinloch, ALundberg, KWait, RWegner, NLim, NZendman, ASaxne, TMalmström, VVenables, P OBJECTIVE: To examine synovial fluid as a site for generating citrullinated antigens, including the candidate autoantigen citrullinated alpha-enolase, in rheumatoid arthritis (RA). METHODS: Synovial fluid was obtained from 20 patients with RA, 20 patients with spondylarthritides (SpA), and 20 patients with osteoarthritis (OA). Samples were resolved using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by staining with Coomassie blue and immunoblotting for citrullinated proteins, alpha-enolase, and the deiminating enzymes peptidylarginine deiminase type 2 (PAD-2) and PAD-4. Proteins from an RA synovial fluid sample were separated by 2-dimensional electrophoresis, and each protein was identified by immunoblotting and mass spectrometry. Antibodies to citrullinated alpha-enolase peptide 1 (CEP-1) and cyclic citrullinated peptide 2 were measured by enzyme-linked immunosorbent assay. RESULTS: Citrullinated polypeptides were detected in the synovial fluid from patients with RA and patients with SpA, but not in OA samples. Alpha-enolase was detected in all of the samples, with mean levels of 6.4 ng/microl in RA samples, 4.3 ng/microl in SpA samples, and <0.9 ng/microl in OA samples. Two-dimensional electrophoresis provided evidence that the alpha-enolase was citrullinated in RA synovial fluid. The citrullinating enzyme PAD-4 was detected in samples from all 3 disease groups. PAD-2 was detected in 18 of the RA samples, in 16 of the SpA samples, and in none of the OA samples. Antibodies to CEP-1 were found in 12 of the RA samples (60%), in none of the SpA samples, and in 1 OA sample. CONCLUSION: These results highlight the importance of synovial fluid for the expression of citrullinated autoantigens in inflammatory arthritis. Whereas the expression of citrullinated proteins is a product of inflammation, the antibody response remains specific for RA. |
| spellingShingle | Kinloch, A Lundberg, K Wait, R Wegner, N Lim, N Zendman, A Saxne, T Malmström, V Venables, P Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title | Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title_full | Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title_fullStr | Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title_full_unstemmed | Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title_short | Synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis. |
| title_sort | synovial fluid is a site of citrullination of autoantigens in inflammatory arthritis |
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