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Johar AS, Mastronardi C, Rojas-Villarraga A, Patel HR, Chuah A, Peng K, Higgins A, Milburn P, Palmer S, Silva-Lara MF, Velez JI, Andrews D, Field M, Huttley G, Goodnow C, Anaya JM, Arcos-Burgos M. Novel and rare functional genomic variants in multiple autoimmune syndrome and Sjögren's syndrome. J Transl Med 2015; 13:173. [PMID: 26031516 PMCID: PMC4450850 DOI: 10.1186/s12967-015-0525-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/08/2015] [Indexed: 12/16/2022] Open
Abstract
Background Multiple autoimmune syndrome (MAS), an extreme phenotype of autoimmune disorders, is a very well suited trait to tackle genomic variants of these conditions. Whole exome sequencing (WES) is a widely used strategy for detection of protein coding and splicing variants associated with inherited diseases. Methods The DNA of eight patients affected by MAS [all of whom presenting with Sjögren’s syndrome (SS)], four patients affected by SS alone and 38 unaffected individuals, were subject to WES. Filters to identify novel and rare functional (pathogenic–deleterious) homozygous and/or compound heterozygous variants in these patients and controls were applied. Bioinformatics tools such as the Human gene connectome as well as pathway and network analysis were applied to test overrepresentation of genes harbouring these variants in critical pathways and networks involved in autoimmunity. Results Eleven novel and rare functional variants were identified in cases but not in controls, harboured in: MACF1, KIAA0754, DUSP12, ICA1, CELA1, LRP1/STAT6, GRIN3B, ANKLE1, TMEM161A, and FKRP. These were subsequently subject to network analysis and their functional relatedness to genes already associated with autoimmunity was evaluated. Notably, the LRP1/STAT6 novel mutation was homozygous in one MAS affected patient and heterozygous in another. LRP1/STAT6 disclosed the strongest plausibility for autoimmunity. LRP1/STAT6 are involved in extracellular and intracellular anti-inflammatory pathways that play key roles in maintaining the homeostasis of the immune system. Further; networks, pathways, and interaction analyses showed that LRP1 is functionally related to the HLA-B and IL10 genes and it has a substantial impact within immunological pathways and/or reaction to bacterial and other foreign proteins (phagocytosis, regulation of phospholipase A2 activity, negative regulation of apoptosis and response to lipopolysaccharides). Further, ICA1 and STAT6 were also closely related to AIRE and IRF5, two very well known autoimmunity genes. Conclusions Novel and rare exonic mutations that may account for autoimmunity were identified. Among those, the LRP1/STAT6 novel mutation has the strongest case for being categorised as potentially causative of MAS given the presence of intriguing patterns of functional interaction with other major genes shaping autoimmunity. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0525-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Angad S Johar
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Claudio Mastronardi
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Adriana Rojas-Villarraga
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia.
| | - Hardip R Patel
- Genome Discovery Unit, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Aaron Chuah
- Genome Discovery Unit, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Kaiman Peng
- Biomolecular Resource Facility, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Angela Higgins
- Biomolecular Resource Facility, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Peter Milburn
- Biomolecular Resource Facility, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Stephanie Palmer
- Biomolecular Resource Facility, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Maria Fernanda Silva-Lara
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Jorge I Velez
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Dan Andrews
- Immunogenomics and Bioinformatics Group, Immunology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Matthew Field
- Immunogenomics and Bioinformatics Group, Immunology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Gavin Huttley
- Biomolecular Resource Facility, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Chris Goodnow
- Immunogenomics and Bioinformatics Group, Immunology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
| | - Juan-Manuel Anaya
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia.
| | - Mauricio Arcos-Burgos
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology and Environment, The Australian National University, Canberra, ACT, Australia.
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Boon ACM, Williams RW, Sinasac DS, Webby RJ. A novel genetic locus linked to pro-inflammatory cytokines after virulent H5N1 virus infection in mice. BMC Genomics 2014; 15:1017. [PMID: 25418976 PMCID: PMC4256927 DOI: 10.1186/1471-2164-15-1017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 10/22/2014] [Indexed: 12/15/2022] Open
Abstract
Background Genetic variation in the human population is a key determinant of influenza disease severity. A single nucleotide polymorphism in the antiviral gene IFITM3 was linked to outcomes during the 2009 H1N1 pandemic. To identify variant host genes associated with increased virus replication and severe disease, we performed a quantitative trait locus analysis on pro-inflammatory cytokine production 48 hours after intranasal infection with highly pathogenic H5N1 influenza virus. Results Pro-inflammatory cytokines CCL2, TNFα and IFN-α, were measured by ELISA in lung homogenates of DBA/2J (D2), C57BL/6J (B6) and 44 different BXD recombinant inbred mouse strains. Virus titer was also assessed in a subset of these animals. CCL2 (8-fold), TNFα (24-fold) and IFN-α (8-fold) concentrations varied significantly among the different BXD RI strains. Importantly, cytokine concentration correlated very well (r =0.86-0.96, P <0.0001) with virus titer suggesting that early cytokine production is due to increased virus infection and replication. Linkage analysis of cytokine concentration revealed a significant locus on chromosome 6 associated with differences in TNFα, IFN-α and CCL2 cytokine concentration (LRS =26). This locus accounted for nearly 20% of the observed phenotypic variation in the BXD population studied. Sequence and RNA expression analysis identified several candidate host genes containing missense mutations or deletions; Samd9l, Ica1, and Slc25a13. To study the role of Slc25a13, we obtained Slc25a13 knockout line, but upon challenge with H5N1 influenza virus observed no effect on CCL2 production, or morbidity and mortality. Conclusion A novel genetic locus on chromosome 6 modulates early pro-inflammatory cytokine production and virus replication after highly pathogenic influenza virus infection. Candidate genes, Samd9l and Ica1, may be important for the control of influenza virus infection and pathogenesis. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1017) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adrianus C M Boon
- Departments of Internal Medicine, Division of Infectious Diseases, Molecular Microbiology and Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
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Fernando R, Vonberg A, Atkins SJ, Pietropaolo S, Pietropaolo M, Smith TJ. Human fibrocytes express multiple antigens associated with autoimmune endocrine diseases. J Clin Endocrinol Metab 2014; 99:E796-803. [PMID: 24517144 PMCID: PMC4010713 DOI: 10.1210/jc.2013-3072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Factors common to multiple autoimmune diseases have been sought vigorously. Graves' disease (GD) and type 1 diabetes mellitus (T1DM) involve end-organ remodeling. Fibrocytes participate in inflammatory diseases and were recently shown to express thyroid-specific proteins such as the thyrotropin receptor and thyroglobulin. OBJECTIVE The objective of the study was to determine whether a broader repertoire of autoantigen expression, such as proteins associated with T1DM, can be ascribed to fibrocytes. DESIGN, SETTING, AND PARTICIPANTS Fibrocytes and fibroblasts were collected and analyzed from healthy individuals and those with autoimmune diseases in an academic clinical practice. MAIN OUTCOME MEASURES Real-time PCR, Western blot analysis, gene promoter analysis, cell transfections, and flow cytometric cell sorting were performed. RESULTS Islet cell antigen ICA512 (IA-2) and islet cell autoantigen of 69 kDa (ICA69), two islet-specific proteins implicated in T1DM, are expressed by fibrocytes from healthy donors and those with T1DM, GD, and multiple sclerosis. Both transcripts are detected by PCR, the proteins are resolved on Western blots, and both gene promoters are active in fibrocytes. Levels of ICA69 are substantially higher than those of IA-2 in fibrocytes. ICA69 localizes to CD34(+) GD orbital fibroblasts putatively derived from fibrocytes, whereas higher levels of IA-2 are found in CD34(-) fibroblasts. CONCLUSIONS In addition to autoantigens implicated in thyroid autoimmunity, fibrocytes and derivative fibroblasts express multiple autoantigens associated with T1DM. This expression results from active gene promoters and abundant steady-state mRNA encoding ICA69 and IA-2. These latest findings demonstrate that fibrocytes express antigens relevant to multiple forms of endocrine autoimmunity. They suggest the potential for these cells playing a direct role in immune reactivity directed at the thyroid and pancreatic islets.
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Affiliation(s)
- Roshini Fernando
- Department of Ophthalmology and Visual Sciences (R.F., S.J.A., T.J.S.), Kellogg Eye Center and Division of Metabolism, Endocrinology, and Diabetes (A.V., S.P., M.P., T.J.S.), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48105
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Delaleu N, Nguyen CQ, Peck AB, Jonsson R. Sjögren's syndrome: studying the disease in mice. Arthritis Res Ther 2011; 13:217. [PMID: 21672284 PMCID: PMC3218871 DOI: 10.1186/ar3313] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by inflammation of exocrine tissues accompanied by a significant loss of their secretory function. Clinical symptoms develop late and there are no diagnostic tests enabling early diagnosis of SS. Thus, particularly to study these covert stages, researchers turn to studying animal models where mice provide great freedom for genetic manipulation and testing the effect of experimental intervention. The present review summarizes current literature pertaining to both spontaneous and extrinsic-factor induced SS-like diseases in mouse models, discussing advantages and disadvantages related to the use of murine models in SS research.
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Affiliation(s)
- Nicolas Delaleu
- Broegelmann Research Laboratory, The Gade Institute, University of Bergen, New Laboratory Building, 5th floor, #5305, 5021 Bergen, Norway.
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Abstract
Sjögren's syndrome is an autoimmune, chronic inflammatory disease characterized by focal mononuclear cell infiltration of exocrine tissues, accompanied by loss of secretory function. The pathogenesis of autoimmune diseases is complex and, therefore, difficult to study in vitro. As of today, the role of initiating factors remains obscure, clinical symptoms develop late, and there are no tests for early diagnosis of SS. Hence, the disease is difficult to detect and treat. Animal models may provide insights into the identification of target antigens, narrowing the relevant pathological immune mechanisms, and to study the evolution of tissue pathology. This review summarizes current knowledge on murine strains, both spontaneous and induced models, used to study Sjögren's syndrome. Special attention is paid to the characteristics of different strains regarding their properties to mimic specific aspects or stages of the disease.
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Affiliation(s)
- Malin V Jonsson
- Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Armauer Hansen Building, 5021, Bergen, Norway
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Neufing PJ, Clancy RM, Jackson MW, Tran HB, Buyon JP, Gordon TP. Exposure and binding of selected immunodominant La/SSB epitopes on human apoptotic cells. ARTHRITIS AND RHEUMATISM 2005; 52:3934-42. [PMID: 16320341 DOI: 10.1002/art.21486] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Opsonization of apoptotic cells by autoantibodies bound to surface membrane-translocated La/SSB antigens may initiate tissue damage in the setting of congenital heart block. By injecting pregnant mice with human anti-La antibodies, we previously demonstrated the formation of IgG-apoptotic cell complexes in the developing mouse fetus; however, the binding of anti-La antibodies to human-specific epitopes could not be addressed. Accordingly, the objective of the current study was to delineate the epitope specificity of human La antibodies that are exposed on the surface of apoptotic cells. METHODS We used fluorescence microscopy and flow cytometry to assess the binding of human anti-La antibodies affinity purified against immunodominant epitopes of La to human cells undergoing spontaneous apoptosis, in a murine xenograft model in vivo and in cultured human fetal cardiocytes rendered apoptotic in vitro, respectively. RESULTS Anti-La antibodies bound to immunodominant epitopes of La within the NH(2)-terminus and the RNA recognition motif (RRM) region of apoptotic human cells, in both xenografts and fetal cardiocytes. In contrast, human antibodies affinity purified against the COOH-terminal La epitope did not bind apoptotic cells in either model. This defines the topology of redistributed La during apoptosis, with surface exposure of the NH(2)-terminus and RRM regions. The potential importance of anti-La NH(2)-terminal and anti-La RRM specificity was confirmed by detection of this reactivity in mothers of children with congenital heart block. CONCLUSION These findings provide insight into both the molecular modification of the La autoantigen during apoptosis and the specificity of antibodies capable of binding to surface-exposed La. Subsequent formation of surface immune complexes may lead to tissue injury in patients with autoimmune diseases such as congenital heart block.
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Affiliation(s)
- Petra J Neufing
- Department of Immunology, Allergy and Arthritis, Flinders University, Adelaide, South Australia, Australia.
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