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Sasai T, Nakashima R, Handa T, Yamano Y, Kondo Y, Matsuda S, Kotani T, Tomioka H, Tachikawa R, Tomii K, Tanizawa K, Nohda Y, Kogame T, Shirakashi M, Hiwa R, Tsuji H, Akizuki S, Yoshifuji H, Mimori T, Kabashima K, Morinobu A. Anti-interferon gamma-inducible protein 16 antibodies: Identification of a novel autoantigen in idiopathic interstitial pneumonia and its clinical characteristics based on a multicenter cohort study. Clin Immunol 2024; 268:110372. [PMID: 39357632 DOI: 10.1016/j.clim.2024.110372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Revised: 09/20/2024] [Accepted: 09/25/2024] [Indexed: 10/04/2024]
Abstract
Autoantibodies are detected in idiopathic interstitial pneumonias (IIPs) without a clear connective tissue disease diagnosis, and their clinical significance is unclear. This study aimed to identify a novel autoantibody in IIPs. We screened 295 IIP patients using a 35S-methionine labeled protein immunoprecipitation assay. Candidate autoantigens were identified via protein array and confirmed by immunoprecipitation. Six sera from 295 IIP patients immunoprecipitated common tetrameric proteins (100 kDa). The protein array identified interferon gamma-inducible protein 16 (IFI16) as the candidate autoantigen. Patients with anti-IFI16 antibodies received immunosuppressants less frequently. Five-year survival rates were 50 %, 69 %, and 63 % (P = 0.60), and acute exacerbation-free rates were 50 %, 96 %, and 84 % (P = 0.15) for patients with anti-IFI16, anti-aminoacyl tRNA antibodies, and others. Anti-IFI16 is a novel autoantibody in IIPs. Patients with this antibody often receive less immunosuppressive therapy and could have a poor prognosis. Further research is needed to refine patient stratification and management.
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Affiliation(s)
- Tsuneo Sasai
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ran Nakashima
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Tomohiro Handa
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuhiko Yamano
- Department of Respiratory Medicine and Clinical Immunology, Tosei General Hospital, Aichi, Japan
| | - Yasuhiro Kondo
- Department of Respiratory Medicine and Clinical Immunology, Tosei General Hospital, Aichi, Japan
| | - Shogo Matsuda
- Department of Internal Medicine IV, Division of Rheumatology, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Takuya Kotani
- Department of Internal Medicine IV, Division of Rheumatology, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Hiromi Tomioka
- Department of Respiratory Medicine, Kobe City Medical Center West Hospital, Kobe, Japan
| | - Ryo Tachikawa
- Department of Respiratory Medicine, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Keisuke Tomii
- Department of Respiratory Medicine, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Kiminobu Tanizawa
- Respiratory Medicine, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
| | - Yasuhiro Nohda
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toshiaki Kogame
- Department of Dermatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mirei Shirakashi
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryosuke Hiwa
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hideaki Tsuji
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shuji Akizuki
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hajime Yoshifuji
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | | | - Kenji Kabashima
- Department of Dermatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akio Morinobu
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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2
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Perurena-Prieto J, Callejas-Moraga EL, Sanz-Martínez MT, Colobran R, Guillén-Del-Castillo A, Simeón-Aznar CP. Prognostic value of anti-IFI16 autoantibodies in pulmonary arterial hypertension and mortality in patients with systemic sclerosis. Med Clin (Barc) 2024; 162:370-377. [PMID: 38302398 DOI: 10.1016/j.medcli.2023.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 02/03/2024]
Abstract
OBJECTIVES To determine the diagnostic value of anti-interferon gamma inducible protein 16 (IFI16) autoantibodies in systemic sclerosis (SSc) patients negative for all tested SSc-specific autoantibodies (SSc-seronegative patients) and to evaluate the clinical significance of these autoantibodies, whether isolated or in the presence of anti-centromere autoantibodies (ACA). METHODS Overall, 58 SSc-seronegative and 66 ACA-positive patients were included in the study. All patients were tested for anti-IFI16 autoantibodies by an in-house direct ELISA. Associations between clinical parameters and anti-IFI16 autoantibodies were analysed. RESULTS Overall, 17.2% of SSc-seronegative and 39.4% of ACA-positive patients were positive for anti-IFI16 autoantibodies. Anti-IFI16 autoantibodies were found only in patients within the limited cutaneous SSc (lcSSc) subset. A positive association between anti-IFI16 positivity and isolated pulmonary arterial hypertension (PAH) was found (odds ratio [OR]=5.07; p=0.014) even after adjusting for ACA status (OR=4.99; p=0.019). Anti-IFI16-positive patients were found to have poorer overall survival than negative patients (p=0.032). Cumulative survival rates at 10, 20 and 30 years were 96.9%, 92.5% and 68.7% for anti-IFI16-positive patients vs. 98.8%, 97.0% and 90.3% for anti-IFI16-negative-patients, respectively. Anti-IFI16-positive patients also had worse overall survival than anti-IFI16-negative patients after adjusting for ACA status in the multivariate Cox analysis (hazard ratio [HR]=3.21; p=0.043). CONCLUSION Anti-IFI16 autoantibodies were associated with isolated PAH and poorer overall survival. Anti-IFI16 autoantibodies could be used as a supplementary marker of lcSSc in SSc-seronegative patients and for identifying ACA-positive patients with worse clinical outcome.
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Affiliation(s)
- Janire Perurena-Prieto
- Immunology Division, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain; Translational Immunology Group, Vall d'Hebron Research Institute (VHIR), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain; Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Bellaterra, Spain
| | | | - María T Sanz-Martínez
- Immunology Division, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Roger Colobran
- Immunology Division, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain; Translational Immunology Group, Vall d'Hebron Research Institute (VHIR), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain; Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Bellaterra, Spain; Department of Clinical and Molecular Genetics, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain.
| | - Alfredo Guillén-Del-Castillo
- Systemic Autoimmune Diseases Unit, Internal Medicine Department, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain.
| | - Carmen P Simeón-Aznar
- Systemic Autoimmune Diseases Unit, Internal Medicine Department, Vall d'Hebron University Hospital (HUVH), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
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Senécal JL, Hoa S, Yang R, Koenig M. Pathogenic roles of autoantibodies in systemic sclerosis: Current understandings in pathogenesis. JOURNAL OF SCLERODERMA AND RELATED DISORDERS 2020; 5:103-129. [PMID: 35382028 PMCID: PMC8922609 DOI: 10.1177/2397198319870667] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/29/2019] [Indexed: 09/12/2023]
Abstract
The potential pathogenic role for autoantibodies in systemic sclerosis has captivated researchers for the past 40 years. This review answers the question whether there is yet sufficient knowledge to conclude that certain serum autoantibodies associated with systemic sclerosis contribute to its pathogenesis. Definitions for pathogenic, pathogenetic and functional autoantibodies are formulated, and the need to differentiate these autoantibodies from natural autoantibodies is emphasized. In addition, seven criteria for the identification of pathogenic autoantibodies are proposed. Experimental evidence is reviewed relevant to the classic systemic sclerosis antinuclear autoantibodies, anti-topoisomerase I and anticentromere, and to functional autoantibodies to endothelin 1 type A receptor, angiotensin II type 1 receptor, muscarinic receptor 3, platelet-derived growth factor receptor, chemokine receptors CXCR3 and CXCR4, estrogen receptor α, and CD22. Pathogenic evidence is also reviewed for anti-matrix metalloproteinases 1 and 3, anti-fibrillin 1, anti-IFI16, anti-eIF2B, anti-ICAM-1, and anti-RuvBL1/RuvBL2 autoantibodies. For each autoantibody, objective evidence for a pathogenic role is scored qualitatively according to the seven pathogenicity criteria. It is concluded that anti-topoisomerase I is the single autoantibody specificity with the most evidence in favor of a pathogenic role in systemic sclerosis, followed by anticentromere. However, these autoantibodies have not been demonstrated yet to fulfill completely the seven proposed criteria for pathogenicity. Their contributory roles to the pathogenesis of systemic sclerosis remain possible but not yet conclusively demonstrated. With respect to functional autoantibodies and other autoantibodies, only a few criteria for pathogenicity are fulfilled. Their common presence in healthy and disease controls suggests that major subsets of these immunoglobulins are natural autoantibodies. While some of these autoantibodies may be pathogenetic in systemic sclerosis, establishing that they are truly pathogenic is a work in progress. Experimental data are difficult to interpret because high serum autoantibody levels may be due to polyclonal B-cell activation. Other limitations in experimental design are the use of total serum immunoglobulin G rather than affinity-purified autoantibodies, the confounding effect of other systemic sclerosis autoantibodies present in total immunoglobulin G and the lack of longitudinal studies to determine if autoantibody titers fluctuate with systemic sclerosis activity and severity. These intriguing new specificities expand the spectrum of autoantibodies observed in systemic sclerosis. Continuing elucidation of their potential mechanistic roles raises hope of a better understanding of systemic sclerosis pathogenesis leading to improved therapies.
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Affiliation(s)
- Jean-Luc Senécal
- Scleroderma Research Chair, Université de Montréal, Montreal, QC, Canada
- Division of Rheumatology, Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
- Autoimmunity Research Laboratory, Research Centre of the Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
| | - Sabrina Hoa
- Division of Rheumatology, Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
- Autoimmunity Research Laboratory, Research Centre of the Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
| | - Roger Yang
- Division of Rheumatology, Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
| | - Martial Koenig
- Autoimmunity Research Laboratory, Research Centre of the Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
- Division of Internal Medicine, Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
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De Andrea M, De Santis M, Caneparo V, Generali E, Sirotti S, Isailovic N, Guidelli GM, Ceribelli A, Fabbroni M, Simpatico A, Cantarini L, Gisondi P, Idolazzi L, Gariglio M, Selmi C. Serum IFI16 and anti-IFI16 antibodies in psoriatic arthritis. Clin Exp Immunol 2019; 199:88-96. [PMID: 31571199 DOI: 10.1111/cei.13376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
Nuclear interferon-inducible protein 16 (IFI16) and anti-IFI16 antibodies have been detected in subjects with several rheumatic diseases, often correlating with disease severity, and in this study we investigated their prevalence and clinical associations in psoriatic arthritis (PsA) compared to psoriasis (Pso). We tested sera and synovial fluids of patients with PsA for IFI16 protein levels by capture enzyme-linked immunosorbent assay (ELISA) and for anti-IFI16 immunoglobulin (Ig)G and IgA by ELISA, protein radio-immunoprecipitation and immunoprecipitation-Western blot of IgG. Sera from patients with Pso and healthy subjects were used as controls, and in a subgroup of patients with PsA we also studied sera after treatment with etanercept. IFI16 was detectable in the sera of 66% of patients with Pso, 46% with PsA and 19% of controls. Among PsA cases, 51% of IFI16-positive cases had elevated levels of C-reactive protein (CRP) compared to 31% of patients with undetectable IFI16. Anti-IFI16 of both IgG and IgA isoforms were detected with significantly higher frequency in PsA and Pso compared to healthy controls, with higher IgG titres in patients with elevated C-reactive protein (CRP) (P = 0·015). Immunoprecipitation confirmed the presence of anti-IFI16 IgG antibodies and these preferentially recognized epitopes outside the N-terminus of the protein. Lastly, IFI16 was detected in one of seven and anti-IFI16 in three of seven synovial fluids from patients with PsA. Therefore, IFI16 and anti-IFI16 are detectable in serum and synovial fluid of PsA patients, especially in cases of elevated CRP.
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Affiliation(s)
- M De Andrea
- Department of Public Health and Paediatric Sciences, Turin Medical School, Turin, Italy.,Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD, Center for Translational Research on Autoimmune and Allergic Diseases, University of Piemonte Orientale, Novara, Italy
| | - M De Santis
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - V Caneparo
- Department of Public Health and Paediatric Sciences, Turin Medical School, Turin, Italy.,Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD, Center for Translational Research on Autoimmune and Allergic Diseases, University of Piemonte Orientale, Novara, Italy
| | - E Generali
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - S Sirotti
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - N Isailovic
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - G M Guidelli
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - A Ceribelli
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - M Fabbroni
- Department of Rheumatology, University of Siena, Siena, Italy
| | - A Simpatico
- Department of Rheumatology, University of Siena, Siena, Italy
| | - L Cantarini
- Department of Rheumatology, University of Siena, Siena, Italy
| | - P Gisondi
- Department of Dermatology, University of Verona, Verona, Italy
| | - L Idolazzi
- Department of Rheumatology, University of Verona, Verona, Italy
| | - M Gariglio
- Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD, Center for Translational Research on Autoimmune and Allergic Diseases, University of Piemonte Orientale, Novara, Italy
| | - C Selmi
- Rheumatology and Clinical Immunology Unit, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy.,Humanitas University, Rozzano, Milan, Italy
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5
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Abstract
PURPOSE OF REVIEW New research continues to provide important insights into the utility of antibody specificities. This review provides an update of recent findings, and the important insights they provide into disease mechanism. RECENT FINDINGS A growing number of autoantibodies have been discovered in scleroderma patients with unique clinical associations. A subgroup of these antibodies may have functional consequences and contribute to disease pathogenesis, driving the vascular and fibrotic phenotype. Recent research into the relationship between malignancy and scleroderma onset provides important new insights into disease mechanism, and highlights the utility of autoantibodies as unique research probes. SUMMARY Continued advances in the study of scleroderma antibody specificities has led to important insights into disease pathogenesis and clinical subgrouping. These advances include newly described specificities, functional antibodies and an emerging understanding of the cancer-scleroderma relationship.
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6
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Caneparo V, Landolfo S, Gariglio M, De Andrea M. The Absent in Melanoma 2-Like Receptor IFN-Inducible Protein 16 as an Inflammasome Regulator in Systemic Lupus Erythematosus: The Dark Side of Sensing Microbes. Front Immunol 2018; 9:1180. [PMID: 29892303 PMCID: PMC5985366 DOI: 10.3389/fimmu.2018.01180] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/11/2018] [Indexed: 12/22/2022] Open
Abstract
Absent in melanoma 2 (AIM2)-like receptors (ALRs) are a newly characterized class of pathogen recognition receptors (PRRs) involved in cytosolic and nuclear pathogen DNA recognition. In recent years, two ALR family members, the interferon (IFN)-inducible protein 16 (IFI16) and AIM2, have been linked to the pathogenesis of various autoimmune diseases, among which systemic lupus erythematosus (SLE) has recently gained increasing attention. SLE patients are indeed often characterized by constitutively high serum IFN levels and increased expression of IFN-stimulated genes due to an abnormal response to pathogens and/or incorrect self-DNA recognition process. Consistently, we and others have shown that IFI16 is overexpressed in a wide range of autoimmune diseases where it triggers production of specific autoantibodies. In addition, evidence from mouse models supports a model whereby ALRs are required for IFN-mediated host response to both exogenous and endogenous DNA. Following interaction with cytoplasmic or nuclear nucleic acids, ALRs can form a functional inflammasome through association with the adaptor ASC [apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD)] and with procaspase-1. Importantly, inflammasome-mediated upregulation of IL-1β and IL-18 production positively correlates with SLE disease severity. Therefore, targeting ALR sensors and their downstream pathways represents a promising alternative therapeutic approach for SLE and other systemic autoimmune diseases.
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Affiliation(s)
- Valeria Caneparo
- Viral Pathogenesis Unit, Department of Public Health and Pediatric Sciences, Turin Medical School, Turin, Italy.,Virology Unit, Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD - Center for Translational Research on Autoimmune and Allergic Disease, University of Piemonte Orientale, Novara, Italy
| | - Santo Landolfo
- Viral Pathogenesis Unit, Department of Public Health and Pediatric Sciences, Turin Medical School, Turin, Italy
| | - Marisa Gariglio
- Virology Unit, Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD - Center for Translational Research on Autoimmune and Allergic Disease, University of Piemonte Orientale, Novara, Italy
| | - Marco De Andrea
- Viral Pathogenesis Unit, Department of Public Health and Pediatric Sciences, Turin Medical School, Turin, Italy.,Virology Unit, Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Department of Translational Medicine, Novara Medical School, Novara, Italy.,Intrinsic Immunity Unit, CAAD - Center for Translational Research on Autoimmune and Allergic Disease, University of Piemonte Orientale, Novara, Italy
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7
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Matsushita T, Takehara K. An update on biomarker discovery and use in systemic sclerosis. Expert Rev Mol Diagn 2017; 17:823-833. [DOI: 10.1080/14737159.2017.1356722] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Takashi Matsushita
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Kazuhiko Takehara
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
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McMahan ZH, Shah AA, Vaidya D, Wigley FM, Rosen A, Casciola-Rosen L. Anti-Interferon-Inducible Protein 16 Antibodies Associate With Digital Gangrene in Patients With Scleroderma. Arthritis Rheumatol 2017; 68:1262-71. [PMID: 26714268 DOI: 10.1002/art.39558] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/15/2015] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To examine the association between anti-interferon-inducible protein 16 (anti-IFI-16) antibodies and clinical features of scleroderma. METHODS Sera from a discovery sample of 94 patients with scleroderma and 47 healthy controls were assayed for anti-IFI-16 antibodies by enzyme-linked immunosorbent assay, and associations were examined using regression analyses. Since anti-IFI-16 autoantibodies were found to be strongly associated with digital gangrene in the discovery sample, a subsequent case-control study (with subjects matched 1:1 on disease duration) was designed for further exploration. Cases were patients with scleroderma and digital gangrene, while controls were patients with scleroderma and Raynaud's phenomenon alone (n = 39 matched pairs). Nonparametric, unadjusted matched pairs analysis as well as univariate and multivariable conditional logistic regression analyses were performed. RESULTS In the discovery sample, anti-IFI-16 antibodies were more prevalent in patients with scleroderma than in healthy controls (18% versus 2%; P = 0.01). Patients with anti-IFI-16 antibodies, compared to anti-IFI-16 antibody-negative patients, were more likely to have limited scleroderma (77% versus 46%; P = 0.03), a longer disease duration (median 15.2 years [interquartile range 10.6-18.3] versus 6.0 years [interquartile range 3.4-13.8]; P < 0.01), digital gangrene (24% versus 4%; P = 0.02), and a low diffusing capacity for carbon monoxide (DLco) (P < 0.01). In the case-control study, 35 (45%) of 78 patients were anti-IFI-16 antibody positive. Anti-IFI-16 antibody levels were significantly higher in cases with digital gangrene than in matched controls (P = 0.02). In analyses adjusted for age, cutaneous scleroderma subtype, smoking, and DLco, high anti-IFI-16 antibody levels were associated with the presence of digital gangrene (adjusted odds ratio 2.3, 95% confidence interval 1.0-5.6, P = 0.05). The odds of having digital gangrene increased with higher anti-IFI-16 antibody titers, in a dose-dependent manner. CONCLUSION Anti-IFI-16 antibodies are associated with digital gangrene in patients with scleroderma. Longitudinal prospective studies exploring anti-IFI-16 antibodies as a disease biomarker, and biologic studies investigating the pathogenicity of these antibodies, are warranted.
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Affiliation(s)
| | - Ami A Shah
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Dhananjay Vaidya
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Antony Rosen
- Johns Hopkins University School of Medicine, Baltimore, Maryland
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Mostmans Y, Cutolo M, Giddelo C, Decuman S, Melsens K, Declercq H, Vandecasteele E, De Keyser F, Distler O, Gutermuth J, Smith V. The role of endothelial cells in the vasculopathy of systemic sclerosis: A systematic review. Autoimmun Rev 2017; 16:774-786. [PMID: 28572048 DOI: 10.1016/j.autrev.2017.05.024] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 04/13/2017] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Systemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by fibroproliferative vasculopathy, immunological abnormalities and progressive fibrosis of multiple organs including the skin. In this study, all English speaking articles concerning the role of endothelial cells (ECs) in SSc vasculopathy and representing biomarkers are systematically reviewed and categorized according to endothelial cell (EC) (dys)function in SSc. METHODS A sensitive search on behalf of the EULAR study group on microcirculation in Rheumatic Diseases was developed in Pubmed, The Cochrane Library and Web of Science to identify articles on SSc vasculopathy and the role of ECs using the following Mesh terms: (systemic sclerosis OR scleroderma) AND pathogenesis AND (endothelial cells OR marker). All selected papers were read and discussed by two independent reviewers. The selection process was based on title, abstract and full text level. Additionally, both reviewers further searched the reference lists of the articles selected for reading on full text level for supplementary papers. These additional articles went through the same selection process. RESULTS In total 193 resulting articles were selected and the identified biomarkers were categorized according to description of EC (dys)function in SSc. The most representing and reliable biomarkers described by the selected articles were adhesion molecules for EC activation, anti-endothelial cell antibodies for EC apoptosis, vascular endothelial growth factor (VEGF), its receptor VEGFR-2 and endostatin for disturbed angiogenesis, endothelial progenitors cells for defective vasculogenesis, endothelin-1 for disturbed vascular tone control, Von Willebrand factor for coagulopathy and interleukin (IL)-33 for EC-immune system communication. Emerging, relatively new discovered biomarkers described in the selected articles, are VEGF165b, IL-17A and the adipocytokines. Finally, myofibroblasts involved in tissue fibrosis in SSc can derive from ECs or epithelial cells through a process known as endothelial-to-mesenchymal transition. CONCLUSION This systematic review emphasizes the growing evidence that SSc is primarily a vascular disease where EC dysfunction is present and prominent in different aspects of cell survival (activation and apoptosis), angiogenesis and vasculogenesis and where disturbed interactions between ECs and various other cells contribute to SSc vasculopathy.
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Affiliation(s)
- Y Mostmans
- Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Dermatology, Laarbeeklaan 101, 1090 Brussels, Belgium; Department of Immunology and Allergology (CIA) Centre Hospitalier Universitaire (CHU) Brugmann, Université Libre de Bruxelles (ULB), Van Gehuchtenplein 4, 1020 Brussels, Belgium.
| | - M Cutolo
- Research Laboratory and Academic Unit of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Genova, Italy
| | - C Giddelo
- Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Dermatology, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - S Decuman
- Ghent University, Department of Internal Medicine, Ghent, Belgium
| | - K Melsens
- Ghent University, Department of Internal Medicine, Ghent, Belgium; Ghent University Hospital, Department of Rheumatology, Ghent, Belgium
| | - H Declercq
- Department of Basic Medical Sciences, Tissue Engineering and Biomaterials Group, Ghent University, Ghent, Belgium
| | - E Vandecasteele
- Department of Cardiology, Ghent University Hospital, Ghent, Belgium
| | - F De Keyser
- Ghent University, Department of Internal Medicine, Ghent, Belgium; Ghent University Hospital, Department of Rheumatology, Ghent, Belgium
| | - O Distler
- Department of Rheumatology, University Hospital Zurich, Zurich, Switzerland
| | - J Gutermuth
- Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Dermatology, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - V Smith
- Ghent University, Department of Internal Medicine, Ghent, Belgium; Ghent University Hospital, Department of Rheumatology, Ghent, Belgium
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10
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Alunno A, Bartoloni E, Bistoni O, Gerli R, Caneparo V, Carubbi F, Landolfo S. Relevance of Interferon-Inducible Protein-16 Rather than Anti-Interferon-Inducible Protein-16 Autoantibodies as a Clinical and Pathogenic Biomarker in Primary Sjögren's Syndrome: Comment on the Article by Baer et al. Arthritis Care Res (Hoboken) 2017; 69:453-454. [DOI: 10.1002/acr.22918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Distinct Anti-IFI16 and Anti-GP2 Antibodies in Inflammatory Bowel Disease and Their Variation with Infliximab Therapy. Inflamm Bowel Dis 2016; 22:2977-2987. [PMID: 27636380 DOI: 10.1097/mib.0000000000000926] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Inflammatory bowel disease (IBD) is characterized by a chronic inflammation of the gut, partly driven by defects in the expression and function of pattern recognition receptors, including the IFI16 protein. Because this protein is a target for autoantibodies and its aberrant expression was reported in colonic mucosa from active patients with ulcerative colitis, we studied its expression and specific seroresponse in patients with IBD before and after infliximab (IFX) therapy. METHODS Anti-IFI16 antibodies (IgG and IgA subtypes) were measured in the sera of 74 patients with IBD: 48 patients with Crohn's disease (CD) and 26 patients with ulcerative colitis, prospectively harvested before and after IFX therapy. Anti-GP2 antibodies (both IgG and IgA subtypes) were also tested for comparison. The patient antibody statuses were qualitatively and quantitatively associated with disease phenotype and response to IFX therapy. RESULTS Significantly higher titers of anti-IFI16 IgG were found in both CD and ulcerative colitis patients compared with healthy controls. Anti-IFI16 IgA titers were also present in patients with CD. Anti-GP2 IgG subtype titers were significantly increased in patients with CD, as were IgA subtype titers. Significant changes in anti-IFI16 IgG subtype titers were observed after IFX in patients with CD who correlated with clinical remission or response. CONCLUSIONS Our results highlight the importance of IFI16 in IBD pathogenesis showing that its de novo overexpression in the gut epithelial cells leads to a breakdown in immune tolerance and the subsequent development of specific autoantibodies. Anti-IFI16 IgG antibodies hold the potential to serve as a biomarker of response to IFX therapy.
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Baer AN, Petri M, Sohn J, Rosen A, Casciola-Rosen L. Association of Antibodies to Interferon-Inducible Protein-16 With Markers of More Severe Disease in Primary Sjögren's Syndrome. Arthritis Care Res (Hoboken) 2016; 68:254-60. [PMID: 26037655 DOI: 10.1002/acr.22632] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/24/2015] [Accepted: 05/26/2015] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Interferon-inducible protein-16 (IFI16) is an intracellular DNA receptor involved in innate immunity. We evaluated the frequency, phenotypic characteristics, and clinical associations of anti-IFI16 antibodies in patients with primary Sjögren's syndrome (SS), and quantitated expression levels of IFI16 in SS and control salivary gland lysates. METHODS Anti-IFI16 antibodies were assayed by enzyme-linked immunosorbent assay using sera from patients with primary SS (n = 133) and from healthy controls (n = 47). Sera from systemic lupus erythematosus (SLE) patients (n = 132) were included as disease controls. Immunoprecipitation of in vitro transcription-translated IFI16 was used to determine which portion of IFI16 the antibodies recognized. Expression of IFI16 in salivary gland lysates was quantitated by immunoblotting. RESULTS Anti-IFI16 antibodies were present in the sera of 38 of 133 SS patients (29%) compared to 1 of 47 healthy controls (2.1%) (SS versus controls; P < 0.0002) and in 31 of 132 SLE controls (24%). In SS, anti-IFI16 antibodies were associated with an abnormal Schirmer's test (P = 0.003), hyperglobulinemia (P = 0.02), antinuclear antibody ≥1:320 (P = 0.01), germinal center-like structures in labial salivary gland lymphoid infiltrates (P = 0.01), and higher focus scores (3.4 versus 2.4; P = 0.005). High-titer IFI16 antibodies were directed against an epitope outside the N-terminus in 9 of 13 SS patients (69%). IFI16 was expressed in 4 of 5 (80%) of SS and 1 of 6 (17%) of control labial salivary glands. CONCLUSION Anti-IFI16 antibodies are a prominent specificity in primary SS and are associated with markers of severe disease. IFI16 is expressed at higher levels in SS salivary glands compared to controls. These high levels in disease target tissue may contribute to the ongoing anti-IFI16 immune response.
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Affiliation(s)
- Alan N Baer
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michelle Petri
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jungsan Sohn
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Antony Rosen
- Johns Hopkins University School of Medicine, Baltimore, Maryland
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Alunno A, Caneparo V, Bistoni O, Caterbi S, Terenzi R, Gariglio M, Bartoloni E, Manzo A, Landolfo S, Gerli R. Circulating Interferon-Inducible Protein IFI16 Correlates With Clinical and Serological Features in Rheumatoid Arthritis. Arthritis Care Res (Hoboken) 2016; 68:440-5. [DOI: 10.1002/acr.22695] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 08/05/2015] [Accepted: 08/11/2015] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Antonio Manzo
- IRCCS Policlinico S. Matteo Foundation/University of Pavia; Pavia Italy
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Alunno A, Caneparo V, Carubbi F, Bistoni O, Caterbi S, Bartoloni E, Giacomelli R, Gariglio M, Landolfo S, Gerli R. Interferon gamma-inducible protein 16 in primary Sjögren's syndrome: a novel player in disease pathogenesis? Arthritis Res Ther 2015; 17:208. [PMID: 26271464 PMCID: PMC4536589 DOI: 10.1186/s13075-015-0722-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/21/2015] [Indexed: 11/19/2022] Open
Abstract
Introduction There is evidence that interferon is involved in the pathogenesis of primary Sjögren’s syndrome (pSS). The interferon-inducible IFI16 protein, normally expressed in cell nuclei, may be overexpressed, mislocalized in the cytoplasm and secreted in the extracellular milieu in several autoimmune disorders. This leads to tolerance breaking to this self-protein with consequent development of anti-IFI16 antibodies. The aim of this study was to identify the pathogenic and clinical significance of IFI16 and anti-IFI16 in pSS. Methods IFI16 and anti-IFI16 were assessed in the serum of 67 pSS patients and over 100 healthy donors by enzyme-linked immunosorbent assay. IFI16 was also evaluated by immunohistochemistry in minor salivary glands of 15 pSS patients and 10 subjects with sicca symptoms but without any clinical, serological or histological features of pSS. Results pSS patients display higher serum levels of both IFI16 and anti-IFI16 compared to healthy donors. IFI16 concentration was directly correlated with disease duration and focus score and inversely correlated with age at diagnosis. Moreover, IFI16 positivity was associated with concurrent positivity for rheumatoid factor. Interestingly, the direct correlation between IFI16 positivity and focus score was independent of disease duration and age at diagnosis. pSS minor salivary glands display marked expression and cytoplasmic mislocalization of IFI16 by acinar and ductal epithelial cells as well as infiltrating lymphocytes and peri/intralesional endothelium compared to minor salivary glands with normal architecture or nonspecific chronic sialadenitis. Within the mononuclear cell infiltrate, IFI16 expression appears to parallel the distribution of T lymphocytes. Conclusion Our data suggest that the IFI16 protein may be involved in the pathogenesis of glandular inflammation occurring in pSS.
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Affiliation(s)
- Alessia Alunno
- Rheumatology Unit, Department of Medicine, University of Perugia, Perugia, Italy.
| | - Valeria Caneparo
- Virology Unit, Department of Translational Medicine, Novara Medical School, Novara, Italy.
| | - Francesco Carubbi
- Rheumatology Unit, Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | - Onelia Bistoni
- Rheumatology Unit, Department of Medicine, University of Perugia, Perugia, Italy.
| | - Sara Caterbi
- Rheumatology Unit, Department of Medicine, University of Perugia, Perugia, Italy.
| | - Elena Bartoloni
- Rheumatology Unit, Department of Medicine, University of Perugia, Perugia, Italy.
| | - Roberto Giacomelli
- Rheumatology Unit, Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | - Marisa Gariglio
- Virology Unit, Department of Translational Medicine, Novara Medical School, Novara, Italy.
| | - Santo Landolfo
- Viral Pathogenesis Unit, Department of Public Health and Pediatric Sciences, Turin Medical School, Turin, Italy.
| | - Roberto Gerli
- Rheumatology Unit, Department of Medicine, University of Perugia, Perugia, Italy.
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Bawadekar M, De Andrea M, Lo Cigno I, Baldanzi G, Caneparo V, Graziani A, Landolfo S, Gariglio M. The Extracellular IFI16 Protein Propagates Inflammation in Endothelial Cells Via p38 MAPK and NF-κB p65 Activation. J Interferon Cytokine Res 2015; 35:441-53. [PMID: 25715050 DOI: 10.1089/jir.2014.0168] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The nuclear interferon-inducible-16 (IFI16) protein acts as DNA sensor in inflammasome signaling and as viral restriction factor. Following Herpesvirus infection or UV-B treatment, IFI16 delocalizes from the nucleus to the cytoplasm and is eventually released into the extracellular milieu. Recently, our group has demonstrated the occurrence of IFI16 in sera of systemic-autoimmune patients that hampers biological activity of endothelia through high-affinity membrane binding. As a continuation, we studied the activity of endotoxin-free recombinant IFI16 (rIFI16) protein on primary endothelial cells. rIFI16 caused dose/time-dependent upregulation of IL-6, IL-8, CCL2, CCL5, CCL20, ICAM1, VCAM1, and TLR4, while secretion of IL-6 and IL-8 was amplified with lipopolysaccharide synergy. Overall, cytokine secretion was completely inhibited in MyD88-silenced cells and partially by TLR4-neutralizing antibodies. By screening downstream signaling pathways, we found that IFI16 activates p38, p44/42 MAP kinases, and NF-kB. In particular, activation of p38 is an early event required for subsequent p44/42 MAP kinases activity and cytokine induction indicating a key role of this kinase in IFI16 signaling. Altogether, our data conclude that extracellular IFI16 protein alone or by synergy with lipopolysaccharide acts like Damage-associated molecular patterns propagating "Danger Signal" through MyD88-dependent TLR-pathway.
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Affiliation(s)
- Mandar Bawadekar
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy .,2 Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) , Novara, Italy .,3 Division of Rheumatology, Department of Medicine, University of Wisconsin-Madison , Wisconsin
| | - Marco De Andrea
- 4 Department of Public Health and Pediatric Sciences, University of Turin , Medical School, Turin, Italy
| | - Irene Lo Cigno
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy .,2 Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) , Novara, Italy
| | - Gianluca Baldanzi
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy
| | - Valeria Caneparo
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy .,2 Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) , Novara, Italy
| | - Andrea Graziani
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy
| | - Santo Landolfo
- 4 Department of Public Health and Pediatric Sciences, University of Turin , Medical School, Turin, Italy
| | - Marisa Gariglio
- 1 Department of Translational Medicine, University of Eastern Piedmont , Novara, Italy .,2 Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) , Novara, Italy
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Mislocalization of the interferon inducible protein IFI16 by environmental insults: implications in autoimmunity. Cytokine Growth Factor Rev 2014; 26:213-9. [PMID: 25466628 DOI: 10.1016/j.cytogfr.2014.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 10/22/2014] [Indexed: 12/30/2022]
Abstract
The nuclear DNA sensor IFI16, a member of PYHIN family of proteins, was previously studied for its role in cell cycle regulation, tumor suppression, apoptosis and DNA damage signaling. Autoantibodies against IFI16 are prevalent in the sera of patients with systemic autoimmunity, thus depicting physiological significance as an autoantigen. At present, the nuclear IFI16 protein has been thoroughly investigated for its role as an innate immune sensor involved in inflammasome signaling and viral restriction. While the sub-cellular localization of IFI16 during such events has been known, very little knowledge about its presence and significance in the extracellular space is available. Recently our group has discovered the presence of circulating IFI16 in the sera from systemic autoimmune patients indicating that in this setting it may be mislocalized form its nuclear site and secreted in the extracellular milieu. In this review, we will discuss the leakage of endogenous IFI16 that has been experimentally proved using in vivo and in vitro models. Also we will comment on the significance of mislocalized inflammasome components in the extracellular space and how it can be responsible for chronic inflammation.
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Connolly DJ, Bowie AG. The emerging role of human PYHIN proteins in innate immunity: implications for health and disease. Biochem Pharmacol 2014; 92:405-14. [PMID: 25199457 DOI: 10.1016/j.bcp.2014.08.031] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 02/07/2023]
Abstract
The innate immune response depends on the ability of immune cells to detect pathogens through germline-encoded pattern recognition receptors (PRRs). Recently discovered PRRs include some members of the Pyrin and HIN domain (PYHIN) family, which are encoded on an interferon-inducible gene cluster located on chromosome 1q23. There are five human PYHIN proteins; Absent in melanoma 2 (AIM2), IFN-γ inducible protein 16 (IFI16), Myeloid cell nuclear differentiation antigen (MNDA), Pyrin and HIN domain family member 1 (PYHIN1) and the recently identified Pyrin domain only protein 3 (POP3). Early studies reported roles for these proteins in cell cycle control, tumour suppression and transcriptional regulation. AIM2 and IFI16 have now been shown to be immune sensors of non-self DNA, such as that produced by viruses in infected cells. AIM2 binds DNA to activate the inflammasome, while IFI16 detection of DNA can lead to the up-regulation of type I interferons or inflammasome activation. Recent studies have shown how IFI16 senses DNA viruses, and also how viruses evade detection by IFI16, while structural studies have greatly advanced our understanding of how AIM2 and IFI16 bind DNA to activate these immune responses. Furthermore, following the identification of POP3, interplay between members of this gene cluster has been established, with POP3 acting as a negative regulator of the AIM2 and IFI16 inflammasomes. In this review we discuss the current understanding of how PYHIN proteins function in innate immunity, their role in disease and the therapeutic possibilities that arise as a result.
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Affiliation(s)
- Dympna J Connolly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Andrew G Bowie
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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Unterholzner L. The interferon response to intracellular DNA: why so many receptors? Immunobiology 2013; 218:1312-21. [PMID: 23962476 DOI: 10.1016/j.imbio.2013.07.007] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/11/2013] [Accepted: 07/17/2013] [Indexed: 12/22/2022]
Abstract
The detection of intracellular DNA has emerged to be a key event in the innate immune response to viruses and intracellular bacteria, and during conditions of sterile inflammation and autoimmunity. One of the consequences of the detection of DNA as a 'stranger' and a 'danger' signal is the production of type I interferons and pro-inflammatory cytokines. Much work has been dedicated to the elucidation of the signalling cascades that activate this DNA-induced gene expression programme. However, while many proteins have been proposed to act as sensors for intracellular DNA in recent years, none has been met with universal acceptance, and a theory linking all the recent observations is, as yet, lacking. This review presents the evidence for the various interferon-inducing DNA receptors proposed to date, and examines the hypotheses that might explain why so many different receptors appear to be involved in the innate immune recognition of intracellular DNA.
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Affiliation(s)
- Leonie Unterholzner
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, DD1 5EH, UK.
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Nuclear DNA sensor IFI16 as circulating protein in autoimmune diseases is a signal of damage that impairs endothelial cells through high-affinity membrane binding. PLoS One 2013; 8:e63045. [PMID: 23690979 PMCID: PMC3653904 DOI: 10.1371/journal.pone.0063045] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/28/2013] [Indexed: 01/30/2023] Open
Abstract
IFI16, a nuclear pathogenic DNA sensor induced by several pro-inflammatory cytokines, is a multifaceted protein with various functions. It is also a target for autoantibodies as specific antibodies have been demonstrated in the sera of patients affected by systemic autoimmune diseases. Following transfection of virus-derived DNA, or treatment with UVB, IFI16 delocalizes from the nucleus to the cytoplasm and is then eventually released into the extracellular milieu. In this study, using an in-house capture enzyme-linked immunsorbent assay we demonstrate that significant levels of IFI16 protein can also exist as circulating form in the sera of autoimmune patients. We also show that the rIFI16 protein, when added in-vitro to endothelial cells, does not affect cell viability, but severely limits their tubulogenesis and transwell migration activities. These inhibitory effects are fully reversed in the presence of anti-IFI16 N-terminal antibodies, indicating that its extracellular activity resides within the N-terminus. It was further demonstrated that endogenous IFI16 released by apoptotic cells bind neighboring cells in a co-culture. Immunofluorescence assays revealed existence of high-affinity binding sites on the plasma membrane of endothelial cells. Free recombinant IFI16 binds these sites on HUVEC with dissociation constant of 2.7 nM, radioiodinated and unlabeled IFI16 compete for binding sites, with inhibition constant (Ki) of 14.43 nM and half maximal inhibitory concentration (IC50) of 67.88 nM; these data allow us to estimate the presence of 250,000 to 450,000 specific binding sites per cell. Corroborating the results from functional assays, this binding could be completely inhibited using anti-IFI16 N-terminal antibody, but not with an antibody raised against the IFI16 C-terminal. Altogether, these data demonstrate that IFI16 may exist as circulating protein in the sera of autoimmune patients which binds endothelial cells causing damage, suggesting a new pathogenic and alarmin function through which this protein triggers the development of autoimmunity.
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Caneparo V, Cena T, De Andrea M, Dell'Oste V, Stratta P, Quaglia M, Tincani A, Andreoli L, Ceffa S, Taraborelli M, Magnani C, Landolfo S, Gariglio M. Anti-IFI16 antibodies and their relation to disease characteristics in systemic lupus erythematosus. Lupus 2013; 22:607-13. [DOI: 10.1177/0961203313484978] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Objective Several studies have shown the presence of anti-IFI16 antibodies in systemic lupus erythematosus (SLE), Sjögren Syndrome (SjS), systemic sclerosis (SSc) and other autoimmune diseases. However, the significance of anti-IFI16 antibodies in SLE has not been fully characterized. The aim of this study was to investigate associations between anti-IFI16 antibodies and clinical and serologic parameters of SLE. Methods An enzyme-linked immunosorbent assay (ELISA) kit was used to measure anti-IFI16 antibodies in the sera of 168 SLE patients, 46 patients with any type of primary glomerulonephritis (GN) and 182 healthy controls (HCs). Associations between anti-IFI16 antibodies and clinical and serologic parameters of SLE were statistically evaluated using both univariate and multivariate analysis. Results Significantly higher anti-IFI16 titres were observed in SLE patients compared to both non-SLE GN and HCs (median levels: 270.1 U/ml vs 132.1 U/ml, p = 0.001, and 52.9 U/ml, p < 0.0001, respectively). With cut-off levels corresponding to the 95th percentile of the control population (113 U/ml), 63% of the SLE patients tested positive for anti-IFI16 autoantibodies, compared to just 24% of patients with primary non-SLE GN and 5% of HCs. The presence of anti-IFI16 antibodies inversely correlated with proteinuria (univariate analysis) and C3 hypocomplementaemia (univariate and multivariate analyses). Conclusions The inverse correlations observed between anti-IFI16 positivity, proteinuria and C3 hypocomplementaemia suggest that anti-IFI16 antibodies do not contribute to renal inflammation in SLE; indeed they may even prevent complement consumption. Anti-IFI16 antibodies hold the potential to serve as a new biomarker of disease activity in SLE.
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Affiliation(s)
- V Caneparo
- Department of Translational Medicine, Medical School of Novara, Italy
- NoToPharm s.r.l, Italy
| | - T Cena
- Department of Translational Medicine, Medical School of Novara, Italy
- Unit of Medical Statistics and Cancer Epidemiology, University-Hospital “Maggiore della Carità”, Italy
| | - M De Andrea
- Department of Translational Medicine, Medical School of Novara, Italy
- Department of Public Health and Pediatric Sciences, Medical School of Turin, Italy
| | - V Dell'Oste
- NoToPharm s.r.l, Italy
- Department of Public Health and Pediatric Sciences, Medical School of Turin, Italy
| | - P Stratta
- Department of Translational Medicine, Medical School of Novara, Italy
- Nephrology Unit, University-Hospital “Maggiore della Carità”, Italy
| | - M Quaglia
- Department of Translational Medicine, Medical School of Novara, Italy
- Nephrology Unit, University-Hospital “Maggiore della Carità”, Italy
| | - A Tincani
- Department of Clinical and Experimental Science, University of Brescia, Italy
- Rheumatology and Clinical Immunology Unit, Spedali Civili, Italy
| | - L Andreoli
- Department of Clinical and Experimental Science, University of Brescia, Italy
- Rheumatology and Clinical Immunology Unit, Spedali Civili, Italy
| | - S Ceffa
- Department of Clinical and Experimental Science, University of Brescia, Italy
- Rheumatology and Clinical Immunology Unit, Spedali Civili, Italy
| | - M Taraborelli
- Department of Clinical and Experimental Science, University of Brescia, Italy
- Rheumatology and Clinical Immunology Unit, Spedali Civili, Italy
| | - C Magnani
- Department of Translational Medicine, Medical School of Novara, Italy
- Unit of Medical Statistics and Cancer Epidemiology, University-Hospital “Maggiore della Carità”, Italy
- Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Medical School of Novara, Italy
| | - S Landolfo
- NoToPharm s.r.l, Italy
- Department of Public Health and Pediatric Sciences, Medical School of Turin, Italy
| | - M Gariglio
- Department of Translational Medicine, Medical School of Novara, Italy
- NoToPharm s.r.l, Italy
- Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Medical School of Novara, Italy
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