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- Espinosa, Alexander, et al.
(författare)
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Loss of the lupus autoantigen Ro52/Trim21 induces tissue inflammation and systemic autoimmunity by disregulating the IL-23-Th17 pathway
- 2009
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 206:8, s. 1661-1671
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Tidskriftsartikel (refereegranskat)abstract
- Ro52/Trim21 is targeted as an autoantigen in systemic lupus erythematosus and Sjögren's syndrome. Polymorphisms in the Ro52 gene have been linked to these autoimmune conditions, but the molecular mechanism by which Ro52 may promote development of systemic autoimmune diseases has not been explored. To address this issue, we generated Ro52-null mice (Ro52(-/-)), which appear phenotypically normal if left unmanipulated. However, Ro52(-/-) mice develop severe dermatitis extending from the site of tissue injury induced by ear tags. The affected mice further develop several signs of systemic lupus with hypergammaglobulinemia, autoantibodies to DNA, proteinuria, and kidney pathology. Ro52, which was recently identified as an E3 ligase, mediates ubiquitination of several members of the interferon regulatory factor (IRF) family, and the Ro52-deficient mice have an enhanced production of proinflammatory cytokines that are regulated by the IRF transcription factors, including cytokines involved in the Th17 pathway (interleukin [IL] 6, IL-12/IL-23p40, and IL-17). Loss of IL-23/IL-17 by genetic deletion of IL-23/p19 in the Ro52(-/-) mice conferred protection from skin disease and systemic autoimmunity. These data reveal that the lupus-associated Ro52 protein is an important negative regulator of proinflammatory cytokine production, and they provide a mechanism by which a defective Ro52 function can lead to tissue inflammation and systemic autoimmunity through the IL-23-Th17 pathway.
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| 2. |
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| 3. |
- Strandberg, Linn, et al.
(författare)
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Interferon-alpha induces up-regulation and nuclear translocation of the Ro52 autoantigen as detected by a panel of novel Ro52-specific monoclonal antibodies
- 2008
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Ingår i: Journal of Clinical Immunology. - : Springer Science and Business Media LLC. - 0271-9142 .- 1573-2592. ; 28:3, s. 220-31
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Tidskriftsartikel (refereegranskat)abstract
- Interferon-alpha (IFN-alpha) has been implicated in the pathogenesis of Sjögren's syndrome and systemic lupus erythematosus. Ro52, which was recently identified as an E3 ligase with anti-proliferative and pro-apoptotic properties, is a major autoantigen targeted in both these conditions. Microarray analyses have indicated up-regulation of Ro52 by IFN-alpha, and the objective of the present study was to address the potential link between IFN-alpha and Ro52. To investigate the influence of IFN-alpha on Ro52 protein levels and cellular localization, we generated a panel of monoclonal antibodies to different domains of Ro52. These novel monoclonal antibodies were characterized by immunoprecipitation, Western blot, and enzyme-linked immunosorbent assay using cell lysates, recombinant Ro52 protein, and synthetic peptides. Ro52 was up-regulated in HeLa cells and human B cells at the messenger RNA and protein levels in response to IFN-alpha stimulation as detected by reverse transcriptase polymerase chain reaction and Western blot. After up-regulation, Ro52 translocated from the cytoplasm to the nucleus. The nuclear translocation of Ro52 was observed after staining with generated monoclonal antibodies specific for both the RING, coiled-coil, and B30.2 domains of Ro52 and the nuclear translocation of Ro52 preceded IFN-alpha-induced apoptotic cell death detected by caspase-3 and TUNEL staining in the treated cultures. In conclusion, our data show that IFN-alpha first induces up-regulation of Ro52 protein and then prompts translocation of the up-regulated Ro52 protein in to the nucleus. The translocation precedes apoptosis of the IFN-alpha exposed cells, suggesting a role for Ro52 in mediating the anti-proliferative or pro-apoptotic effects of the autoimmune-related cytokine IFN-alpha.
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