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Ray D, Strickland FM, Richardson BC. Oxidative stress and dietary micronutrient deficiencies contribute to overexpression of epigenetically regulated genes by lupus T cells. Clin Immunol 2018; 196:97-102. [PMID: 29654844 DOI: 10.1016/j.clim.2018.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 11/30/2022]
Abstract
Patients with active lupus have altered T cells characterized by low DNA methyltransferase levels. We hypothesized that low DNA methyltransferase levels synergize with low methionine levels to cause greater overexpression of genes normally suppressed by DNA methylation. CD4+ T cells from lupus patients and controls were stimulated with PHA then cultured in custom media with normal or low methionine levels. Oxidative stress was induced by treating the normal CD4+ T cells with peroxynitrite prior to culture. Methylation sensitive gene expression was measured by flow cytometry. Results showed low methionine levels caused greater overexpression of methylation sensitive genes in peroxynitrite treated T cells relative to untreated T cells, and in T cells from lupus patients relative to T cells from healthy controls. In conclusion, low dietary transmethylation micronutrient levels and low DNA methyltransferase levels caused either by oxidative stress or lupus, have additive effects on methylation sensitive T cell gene expression.
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Affiliation(s)
- Donna Ray
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Faith M Strickland
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Bruce C Richardson
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, United States.
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Strickland FM, Li Y, Johnson K, Sun Z, Richardson BC. CD4(+) T cells epigenetically modified by oxidative stress cause lupus-like autoimmunity in mice. J Autoimmun 2015; 62:75-80. [PMID: 26165613 DOI: 10.1016/j.jaut.2015.06.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/01/2015] [Accepted: 06/07/2015] [Indexed: 10/23/2022]
Abstract
Lupus develops when genetically predisposed people encounter environmental agents such as UV light, silica, infections and cigarette smoke that cause oxidative stress, but how oxidative damage modifies the immune system to cause lupus flares is unknown. We previously showed that oxidizing agents decreased ERK pathway signaling in human T cells, decreased DNA methyltransferase 1 and caused demethylation and overexpression of genes similar to those from patients with active lupus. The current study tested whether oxidant-treated T cells can induce lupus in mice. We adoptively transferred CD4(+) T cells treated in vitro with oxidants hydrogen peroxide or nitric oxide or the demethylating agent 5-azacytidine into syngeneic mice and studied the development and severity of lupus in the recipients. Disease severity was assessed by measuring anti-dsDNA antibodies, proteinuria, hematuria and by histopathology of kidney tissues. The effect of the oxidants on expression of CD40L, CD70, KirL1 and DNMT1 genes and CD40L protein in the treated CD4(+) T cells was assessed by Q-RT-PCR and flow cytometry. H2O2 and ONOO(-) decreased Dnmt1 expression in CD4(+) T cells and caused the upregulation of genes known to be suppressed by DNA methylation in patients with lupus and animal models of SLE. Adoptive transfer of oxidant-treated CD4(+) T cells into syngeneic recipients resulted in the induction of anti-dsDNA antibody and glomerulonephritis. The results show that oxidative stress may contribute to lupus disease by inhibiting ERK pathway signaling in T cells leading to DNA demethylation, upregulation of immune genes and autoreactivity.
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Affiliation(s)
- Faith M Strickland
- Department of Internal Medicine, Rheumatology Division, The University of Michigan, Ann Arbor, MI 48109, USA.
| | - YePeng Li
- Department of Internal Medicine, Rheumatology Division, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Kent Johnson
- Department of Pathology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhichao Sun
- Department of Biostatistics, School of Public Health, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Bruce C Richardson
- Department of Internal Medicine, Rheumatology Division, The University of Michigan, Ann Arbor, MI 48109, USA; Department of Medicine, Ann Arbor VA Medical Center, USA
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Kennedy WP, Maciuca R, Wolslegel K, Tew W, Abbas AR, Chaivorapol C, Morimoto A, McBride JM, Brunetta P, Richardson BC, Davis JC, Behrens TW, Townsend MJ. Association of the interferon signature metric with serological disease manifestations but not global activity scores in multiple cohorts of patients with SLE. Lupus Sci Med 2015; 2:e000080. [PMID: 25861459 PMCID: PMC4379884 DOI: 10.1136/lupus-2014-000080] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/03/2015] [Accepted: 03/11/2015] [Indexed: 01/01/2023]
Abstract
Objectives The interferon (IFN) signature (IS) in patients with systemic lupus erythematosus (SLE) includes over 100 genes induced by type I IFN pathway activation. We developed a method to quantify the IS using three genes—the IS metric (ISM)—and characterised the clinical characteristics of patients with SLE with different ISM status from multiple clinical trials. Methods Blood microarray expression data from a training cohort of patients with SLE confirmed the presence of the IS and identified surrogate genes. We assayed these genes in a quantitative PCR (qPCR) assay, yielding an ISM from the IS. The association of ISM status with clinical disease characteristics was assessed in patients with extrarenal lupus and lupus nephritis from four clinical trials. Results Three genes, HERC5, EPSTI and CMPK2, correlated well with the IS (p>0.96), and composed the ISM qPCR assay. Using the 95th centile for healthy control data, patients with SLE from different studies were classified into two ISM subsets—ISM-Low and ISM-High—that are longitudinally stable over 36 weeks. Significant associations were identified between ISM-High status and higher titres of anti-dsDNA antibodies, presence of anti extractable nuclear antigen autoantibodies, elevated serum B cell activating factor of the tumour necrosis factor family (BAFF) levels, and hypocomplementaemia. However, measures of overall clinical disease activity were similar for ISM-High and ISM-Low groups. Conclusions The ISM is an IS biomarker that divides patients with SLE into two subpopulations—ISM-High and ISM-Low—with differing serological manifestations. The ISM does not distinguish between high and low disease activity, but may have utility in identifying patients more likely to respond to treatment(s) targeting IFN-α. Clinicaltrials.gov registration number NCT00962832.
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Affiliation(s)
- William P Kennedy
- Departments of Early Clinical Development , Genentech , South San Francisco, California , USA
| | - Romeo Maciuca
- Department of Biostatistics, Genentech , South San Francisco , California , USA
| | - Kristen Wolslegel
- Department of ITGR Diagnostics Discovery , Genentech , South San Francisco, California , USA
| | - Wei Tew
- Department of ITGR Diagnostics Discovery , Genentech , South San Francisco, California , USA
| | - Alexander R Abbas
- Department of Bioinformatics and Computational Biology , Genentech , South San Francisco, California , USA
| | - Christina Chaivorapol
- Department of Bioinformatics and Computational Biology , Genentech , South San Francisco, California , USA
| | - Alyssa Morimoto
- Department of Bioanalytical Sciences , Genentech , South San Francisco, California , USA
| | - Jacqueline M McBride
- Department of Pharmacodynamic Biomarkers ITGR , Genentech , South San Francisco, California , USA
| | - Paul Brunetta
- Department of Late Stage Immunology Product Development , Genentech , South San Francisco, California , USA
| | - Bruce C Richardson
- Department of Medicine , University of Michigan and the Ann Arbor VA Hospital , Ann Arbor, Michigan , USA
| | - John C Davis
- Departments of Early Clinical Development , Genentech , South San Francisco, California , USA
| | - Timothy W Behrens
- Department of ITGR Human Genetics , Genentech , South San Francisco, California , USA
| | - Michael J Townsend
- Department of ITGR Diagnostics Discovery , Genentech , South San Francisco, California , USA
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Patel DR, Richardson BC. Drug-induced lupus. Rheumatology (Oxford) 2015. [DOI: 10.1016/b978-0-323-09138-1.00132-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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5
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Abstract
A dose-dependent combination of environmental exposures, estrogenic hormones and genetic predisposition is thought to be required for lupus to develop and flare, but how the environment modifies the immune system in genetically predisposed people is unclear. Current evidence indicates that environmental agents that inhibit DNA methylation can convert normal antigen-specific CD4+ T lymphocytes into autoreactive, cytotoxic, pro-inflammatory cells that are sufficient to cause lupus-like autoimmunity in animal models, and that the same changes in DNA methylation characterize CD4+ T cells from patients with active lupus. Environmental agents implicated in inhibiting T-cell DNA methylation include the lupus-inducing drugs procainamide and hydralazine, as well as diet, and agents causing oxidative stress, such as smoking, UV light exposure, and infections, which have been associated with lupus onset or disease activity. Other studies demonstrate that demethylated T cells cause only anti-DNA antibodies in mice lacking a genetic predisposition to lupus, but are sufficient to cause lupus-like autoimmunity in genetically predisposed mice and likely people, and that estrogens augment the disease. Collectively, these studies suggest that environmental agents that inhibit DNA methylation, together with lupus genes and estrogens or endocrine disruptors, combine in a dose-dependent fashion to cause lupus flares.
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Affiliation(s)
- E C Somers
- 1Department of Medicine, University of Michigan, Ann Arbor, USA
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Li Y, Gorelik G, Strickland FM, Richardson BC. Oxidative stress, T cell DNA methylation, and lupus. Arthritis Rheumatol 2014; 66:1574-82. [PMID: 24577881 PMCID: PMC4141415 DOI: 10.1002/art.38427] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/13/2014] [Indexed: 12/30/2022]
Abstract
Objective Lupus develops when genetically predisposed people encounter environmental agents, such as ultraviolet light, silica, infections, and cigarette smoke, that cause oxidative stress, but how oxidative damage modifies the immune system to cause lupus flares is unknown. We previously showed that inhibiting DNA methylation in CD4+ T cells by blocking ERK pathway signaling is sufficient to alter gene expression, and that the modified cells cause lupus-like autoimmunity in mice. We also reported that T cells from patients with active lupus have decreased ERK pathway signaling, have decreased DNA methylation, and overexpress genes normally suppressed by DNA methylation. This study was undertaken to test whether oxidizing agents decrease ERK pathway signaling in T cells, decrease DNA methyltransferase levels, and cause demethylation and overexpression of T cell genes similar to that found in T cells from patients with active lupus. Methods CD4+ T cells were treated with the oxidizers H2O2 or ONOO−. Effects on ERK pathway signaling were measured by immunoblotting, DNA methyltransferase 1 (DNMT-1) levels were measured by reverse transcriptase–polymerase chain reaction (RT-PCR), and the methylation and expression of T cell genes were measured using flow cytometry, RT-PCR, and bisulfite sequencing. Results H2O2 and ONOO− inhibited ERK pathway signaling in T cells by inhibiting the upstream regulator protein kinase Cδ, decreased DNMT-1 levels, and caused demethylation and overexpression of genes previously shown to be suppressed by DNA methylation in T cells from patients with active lupus. Conclusion Our findings indicate that oxidative stress may contribute to human lupus flares by inhibiting ERK pathway signaling in T cells to decrease DNMT-1 and cause DNA demethylation.
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Gorelik GJ, Yarlagadda S, Richardson BC. Omission of Author Name in the Article by Gorelik et al (Arthritis Rheum, September 2012). Arthritis Rheumatol 2014. [DOI: 10.1002/art.38395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Several advances in 2013 have improved our understanding of how epigenetic mechanisms affect autoimmune disorders. Many new insights were made into the regulation of gene expression by DNA methylation in systemic lupus erythematosus. For rheumatoid arthritis, complex interrelationships between DNA methylation and microRNAs in regulating gene expression were described.
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Affiliation(s)
- Bruce C Richardson
- Ann Arbor Veterans Administration Medical Center, Department of Medicine, University of Michigan, 3007 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
| | - Dipak R Patel
- Department of Rheumatology/Immunology, University of Michigan, 3007 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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Strickland FM, Hewagama A, Wu A, Sawalha AH, Delaney C, Hoeltzel MF, Yung R, Johnson K, Mickelson B, Richardson BC. Diet influences expression of autoimmune-associated genes and disease severity by epigenetic mechanisms in a transgenic mouse model of lupus. Arthritis Rheum 2013; 65:1872-81. [PMID: 23576011 PMCID: PMC3735138 DOI: 10.1002/art.37967] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 04/02/2013] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Lupus flares occur when genetically predisposed individuals encounter appropriate environmental agents. Current evidence indicates that the environment contributes by inhibiting T cell DNA methylation, causing overexpression of normally silenced genes. DNA methylation depends on both dietary transmethylation micronutrients and ERK-regulated DNA methyltransferase 1 (DNMT-1) levels. We used transgenic mice to study the effect of interactions between diet, DNMT-1 levels, and genetic predisposition on the development and severity of lupus. METHODS A doxycycline-inducible ERK defect was bred into lupus-resistant (C57BL/6) and lupus-susceptible (C57BL/6 × SJL) mouse strains. Doxycycline-treated mice were fed a standard commercial diet for 18 weeks and then switched to a transmethylation micronutrient-supplemented (MS) or -restricted (MR) diet. Disease severity was assessed by examining anti-double-stranded DNA (anti-dsDNA) antibody levels, the presence of proteinuria and hematuria, and by histopathologic analysis of kidney tissues. Pyrosequencing was used to determine micronutrient effects on DNA methylation. RESULTS Doxycycline induced modest levels of anti-dsDNA antibodies in C57BL/6 mice and higher levels in C57BL/6 × SJL mice. Doxycycline-treated C57BL/6 × SJL mice developed hematuria and glomerulonephritis on the MR and standard diets but not the MS diet. In contrast, C57BL/6 mice developed kidney disease only on the MR diet. Decreasing ERK signaling and methyl donors also caused demethylation and overexpression of the CD40lg gene in female mice, consistent with demethylation of the second X chromosome. Both the dietary methyl donor content and the duration of treatment influenced methylation and expression of the CD40lg gene. CONCLUSION Dietary micronutrients that affect DNA methylation can exacerbate or ameliorate disease in this transgenic murine lupus model, and contribute to lupus susceptibility and severity through genetic-epigenetic interactions.
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Abstract
Systemic lupus erythematosus is a chronic relapsing autoimmune disease that primarily
afflicts women, and both a genetic predisposition and appropriate environmental
exposures are required for lupus to develop and flare. The genetic requirement is
evidenced by an increased concordance in identical twins and by the validation of at
least 35 single-nucleotide polymorphisms predisposing patients to lupus. Genes alone,
though, are not enough. The concordance of lupus in identical twins is often
incomplete, and when concordant, the age of onset is usually different. Lupus is also
not present at birth, but once the disease develops, it typically follows a chronic
relapsing course. Thus, genes alone are insufficient to cause human lupus, and
additional factors encountered in the environment and over time are required to
initiate the disease and subsequent flares. The nature of the environmental
contribution, though, and the mechanisms by which environmental agents modify the
immune response to cause lupus onset and flares in genetically predisposed people
have been controversial. Reports that the lupus-inducing drugs procainamide and
hydralazine are epigenetic modifiers, that epigenetically modified T cells are
sufficient to cause lupus-like autoimmunity in animal models, and that patients with
active lupus have epigenetic changes similar to those caused by procainamide and
hydralazine have prompted a growing interest in how epigenetic alterations contribute
to this disease. Understanding how epigenetic mechanisms modify T cells to contribute
to lupus requires an understanding of how epigenetic mechanisms regulate gene
expression. The roles of DNA methylation, histone modifications, and microRNAs in
lupus pathogenesis will be reviewed here.
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Sánchez E, Comeau ME, Freedman BI, Kelly JA, Kaufman KM, Langefeld CD, Brown EE, Alarcón GS, Kimberly RP, Edberg JC, Ramsey-Goldman R, Petri M, Reveille JD, Vilá LM, Merrill JT, Tsao BP, Kamen DL, Gilkeson GS, James JA, Vyse TJ, Gaffney PM, Jacob CO, Niewold TB, Richardson BC, Harley JB, Alarcón-Riquelme ME, Sawalha AH. Identification of novel genetic susceptibility loci in African American lupus patients in a candidate gene association study. ACTA ACUST UNITED AC 2013; 63:3493-501. [PMID: 21792837 DOI: 10.1002/art.30563] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Candidate gene and genome-wide association studies have identified several disease susceptibility loci in lupus patients. These studies have largely been performed in lupus patients who are Asian or of European ancestry. This study was undertaken to examine whether some of these same susceptibility loci increase lupus risk in African American individuals. METHODS Single-nucleotide polymorphisms tagging 15 independent lupus susceptibility loci were genotyped in a set of 1,724 lupus patients and 2,024 healthy controls of African American descent. The loci examined included PTPN22, FCGR2A, TNFSF4, STAT4, CTLA4, PDCD1, PXK, BANK1, MSH5 (HLA region), CFB (HLA region), C8orf13-BLK region, MBL2, KIAA1542, ITGAM, and MECP2/IRAK1. RESULTS We found the first evidence of genetic association between lupus in African American patients and 5 susceptibility loci (C8orf13-BLK, BANK1, TNFSF4, KIAA1542, and CTLA4; P = 8.0 × 10⁻⁶, P = 1.9 × 10⁻⁵, P = 5.7 × 10⁻⁵, P = 0.00099, and P = 0.0045, respectively). Further, we confirmed the genetic association between lupus and 5 additional lupus susceptibility loci (ITGAM, MSH5, CFB, STAT4, and FCGR2A; P = 7.5 × 10⁻¹¹, P = 5.2 × 10⁻⁸, P = 8.7 × 10⁻⁷ , P = 0.0058, and P = 0.0070, respectively), and provided evidence, for the first time, of genome-wide significance for the association between lupus in African American patients and ITGAM and MSH5 (HLA region). CONCLUSION These findings provide evidence of novel genetic susceptibility loci for lupus in African Americans and demonstrate that the majority of lupus susceptibility loci examined confer lupus risk across multiple ethnicities.
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Affiliation(s)
- Elena Sánchez
- Oklahoma Medical Research Foundation, Oklahoma City, USA
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Gorelik GJ, Yarlagadda S, Patel DR, Richardson BC. Protein kinase Cδ oxidation contributes to ERK inactivation in lupus T cells. ACTA ACUST UNITED AC 2012; 64:2964-74. [PMID: 22549474 DOI: 10.1002/art.34503] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE CD4+ T cells from patients with active lupus have impaired ERK pathway signaling that decreases DNA methyltransferase expression, resulting in DNA demethylation, overexpression of immune genes, and autoimmunity. The ERK pathway defect is due to impaired phosphorylation of T(505) in the protein kinase Cδ (PKCδ) activation loop. However, the mechanisms that prevent PKCδ T(505) phosphorylation in lupus T cells are unknown. Others have reported that oxidative modifications, and nitration in particular, of T cells as well as serum proteins correlate with lupus disease activity. We undertook this study to test our hypothesis that nitration inactivates PKCδ, contributing to impaired ERK pathway signaling in lupus T cells. METHODS CD4+ T cells were purified from lupus patients and controls and then stimulated with phorbol myristate acetate (PMA). Signaling protein levels, nitration, and phosphorylation were quantitated by immunoprecipitation and immunoblotting of T cell lysates. Transfections were performed by electroporation. RESULTS Treating CD4+ T cells with peroxynitrite nitrated PKCδ, preventing PKCδ T(505) phosphorylation and inhibiting ERK pathway signaling similar to that observed in lupus T cells. Patients with active lupus had higher nitrated T cell PKCδ levels than did controls, which correlated directly with disease activity, and antinitrotyrosine immunoprecipitations demonstrated that nitrated PKCδ, but not unmodified PKCδ, was refractory to PMA-stimulated T(505) phosphorylation, similar to PKCδ in peroxynitrite-treated cells. CONCLUSION Oxidative stress causes PKCδ nitration, which prevents its phosphorylation and contributes to the decreased ERK signaling in lupus T cells. These results identify PKCδ as a link between oxidative stress and the T cell epigenetic modifications in lupus.
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Huang SK, Scruggs AM, Donaghy J, McEachin RC, Fisher AS, Richardson BC, Peters-Golden M. Prostaglandin E₂ increases fibroblast gene-specific and global DNA methylation via increased DNA methyltransferase expression. FASEB J 2012; 26:3703-14. [PMID: 22645246 DOI: 10.1096/fj.11-203323] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although alterations in DNA methylation patterns have been associated with specific diseases and environmental exposures, the mediators and signaling pathways that direct these changes remain understudied. The bioactive lipid mediator prostaglandin E(2) (PGE(2)) has been shown to exert a myriad of effects on cell survival, proliferation, and differentiation. Here, we report that PGE(2) also signals to increase global DNA methylation and DNA methylation machinery in fibroblasts. HumanMethylation27 BeadChip array analysis of primary fetal (IMR-90) and adult lung fibroblasts identified multiple genes that were hypermethylated in response to PGE(2). PGE(2), compared with nontreated controls, increased expression and activity (EC(50)∼10(7) M) of one specific isoform of DNA methyltransferase, DNMT3a. Silencing of DNMT3a negated the ability of PGE(2) to increase DNMT activity. The increase in DNMT3a expression was mediated by PGE(2) signaling via its E prostanoid 2 receptor and the second messenger cAMP. PGE(2), compared with the untreated control, increased the expression and activity of Sp1 and Sp3 (EC(50)∼3×10(7) M), transcription factors known to increase DNMT3a expression, and inhibition of these transcription factors abrogated the PGE(2) increase of DNMT3a expression. These findings were specific to fibroblasts, as PGE(2) decreased DNMT1 and DNMT3a expression in RAW macrophages. Taken together, these findings establish that DNA methylation is regulated by a ubiquitous bioactive endogenous mediator. Given that PGE(2) biosynthesis is modulated by environmental toxins, various disease states, and commonly used pharmacological agents, these findings uncover a novel mechanism by which alterations in DNA methylation patterns may arise in association with disease and certain environmental exposures.
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Affiliation(s)
- Steven K Huang
- Division of Pulmonary and Critical Care Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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Hughes T, Adler A, Kelly JA, Kaufman KM, Williams A, Langefeld CD, Brown EE, Alarcón GS, Kimberly RP, Edberg JC, Ramsey-Goldman R, Petri M, Boackle SA, Stevens AM, Reveille JD, Sanchez E, Martin J, Niewold TB, Vilá LM, Scofield RH, Gilkeson GS, Gaffney PM, Criswell LA, Moser KL, Merrill JT, Jacob CO, Tsao BP, James JA, Vyse TJ, Alarcón-Riquelme ME, Harley JB, Richardson BC, Sawalha AH. Evidence for gene-gene epistatic interactions among susceptibility loci for systemic lupus erythematosus. Arthritis Rheum 2012; 64:485-92. [PMID: 21952918 PMCID: PMC3268866 DOI: 10.1002/art.33354] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Several confirmed genetic susceptibility loci for lupus have been described. To date, no clear evidence for genetic epistasis in lupus has been established. The aim of this study was to test for gene-gene interactions in a number of known lupus susceptibility loci. METHODS Eighteen single-nucleotide polymorphisms tagging independent and confirmed lupus susceptibility loci were genotyped in a set of 4,248 patients with lupus and 3,818 normal healthy control subjects of European descent. Epistasis was tested by a 2-step approach using both parametric and nonparametric methods. The false discovery rate (FDR) method was used to correct for multiple testing. RESULTS We detected and confirmed gene-gene interactions between the HLA region and CTLA4, IRF5, and ITGAM and between PDCD1 and IL21 in patients with lupus. The most significant interaction detected by parametric analysis was between rs3131379 in the HLA region and rs231775 in CTLA4 (interaction odds ratio 1.19, Z = 3.95, P = 7.8 × 10(-5) [FDR ≤0.05], P for multifactor dimensionality reduction = 5.9 × 10(-45)). Importantly, our data suggest that in patients with lupus, the presence of the HLA lupus risk alleles in rs1270942 and rs3131379 increases the odds of also carrying the lupus risk allele in IRF5 (rs2070197) by 17% and 16%, respectively (P = 0.0028 and P = 0.0047, respectively). CONCLUSION We provide evidence for gene-gene epistasis in systemic lupus erythematosus. These findings support a role for genetic interaction contributing to the complexity of lupus heritability.
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Affiliation(s)
- Travis Hughes
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Adam Adler
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Jennifer A. Kelly
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kenneth M. Kaufman
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Adrienne Williams
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC, USA
| | - Carl D. Langefeld
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC, USA
| | - Elizabeth E. Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Graciela S. Alarcón
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert P. Kimberly
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeffrey C. Edberg
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rosalind Ramsey-Goldman
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Michelle Petri
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Susan A. Boackle
- Division of Rheumatology, School of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Anne M. Stevens
- Division of Rheumatology, Department of Pediatrics, University of Washington, and Center for Immunity and Immunotherapies, Seattle Children’s Research Institute, Seattle, WA, USA
| | - John D. Reveille
- Department of Medicine, University of Texas-Houston Health Science Center, Houston, TX, USA
| | - Elena Sanchez
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Javier Martin
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Timothy B. Niewold
- Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Luis M. Vilá
- Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
| | - R Hal Scofield
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Gary S. Gilkeson
- Department of Medicine, Division of Rheumatology, Medical University of South Carolina, Charleston, SC, USA
| | - Patrick M. Gaffney
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Lindsey A. Criswell
- Rosalind Russell Medical Research Center for Arthritis, University of California, San Francisco, San Francisco, CA, USA
| | - Kathy L. Moser
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Joan T. Merrill
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Clinical Pharmacology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Chaim O. Jacob
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Betty P. Tsao
- Division of Rheumatology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Judith A. James
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Timothy J. Vyse
- Divisions of Genetics and Molecular Medicine and Immunology, Infection and Inflammatory Disease, King’s College London, Guy’s Hospital, London, UK
| | - Marta E. Alarcón-Riquelme
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Center for Genomics and Oncological Research Pfizer-University of Granada-Junta de Andalucia, Granada, Spain
| | - John B. Harley
- Rheumatology Division and Autoimmune Genomics Center, Cincinnati Children’s Hospital Medical Center; and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Bruce C. Richardson
- Division of Rheumatology, University of Michigan; and US Department of Veterans Affairs Medical Center, Ann Arbor, Michigan
| | - Amr H. Sawalha
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
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15
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Strickland FM, Hewagama A, Lu Q, Wu A, Hinderer R, Webb R, Johnson K, Sawalha AH, Delaney C, Yung R, Richardson BC. Environmental exposure, estrogen and two X chromosomes are required for disease development in an epigenetic model of lupus. J Autoimmun 2011; 38:J135-43. [PMID: 22142890 DOI: 10.1016/j.jaut.2011.11.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 11/03/2011] [Accepted: 11/08/2011] [Indexed: 10/14/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease primarily afflicting women. The reason for the gender bias is unclear, but genetic susceptibility, estrogen and environmental agents appear to play significant roles in SLE pathogenesis. Environmental agents can contribute to lupus susceptibility through epigenetic mechanisms. We used (C57BL/6xSJL)F1 mice transgenic for a dominant-negative MEK (dnMEK) that was previously shown to be inducibly and selectively expressed in T cells. In this model, induction of the dnMEK by doxycycline treatment suppresses T cell ERK signaling, decreasing DNA-methyltransferase expression and resulting in DNA demethylation, overexpression of immune genes Itgal (CD11a) and Tnfsf7 (CD70), and anti-dsDNA antibody. To examine the role of gender and estrogen in this model, male and female transgenic mice were neutered and implanted with time-release pellets delivering placebo or estrogen. Doxycycline induced IgG anti-dsDNA antibodies in intact and neutered, placebo-treated control female but not male transgenic mice. Glomerular IgG deposits were also found in the kidneys of female but not male transgenic mice, and not in the absence of doxycycline. Estrogen enhanced anti-dsDNA IgG antibodies only in transgenic, ERK-impaired female mice. Decreased ERK activation also resulted in overexpression and demethylation of the X-linked methylation-sensitive gene CD40lg in female but not male mice, consistent with demethylation of the second X chromosome in the females. The results show that both estrogen and female gender contribute to the female predisposition in lupus susceptibility through hormonal and epigenetic X-chromosome effects and through suppression of ERK signaling by environmental agents.
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Affiliation(s)
- Faith M Strickland
- Department of Internal Medicine, Rheumatology Division, The University of Michigan, Ann Arbor, MI 48109-2200, USA.
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Hughes T, Adler A, Merrill JT, Kelly JA, Kaufman KM, Williams A, Langefeld CD, Gilkeson GS, Sanchez E, Martin J, Boackle SA, Stevens AM, Alarcón GS, Niewold TB, Brown EE, Kimberly RP, Edberg JC, Ramsey-Goldman R, Petri M, Reveille JD, Criswell LA, Vilá LM, Jacob CO, Gaffney PM, Moser KL, Vyse TJ, Alarcón-Riquelme ME, James JA, Tsao BP, Scofield RH, Harley JB, Richardson BC, Sawalha AH. Analysis of autosomal genes reveals gene-sex interactions and higher total genetic risk in men with systemic lupus erythematosus. Ann Rheum Dis 2011; 71:694-9. [PMID: 22110124 DOI: 10.1136/annrheumdis-2011-200385] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVES Systemic lupus erythematosus (SLE) is a sexually dimorphic autoimmune disease which is more common in women, but affected men often experience a more severe disease. The genetic basis of sexual dimorphism in SLE is not clearly defined. A study was undertaken to examine sex-specific genetic effects among SLE susceptibility loci. METHODS A total of 18 autosomal genetic susceptibility loci for SLE were genotyped in a large set of patients with SLE and controls of European descent, consisting of 5932 female and 1495 male samples. Sex-specific genetic association analyses were performed. The sex-gene interaction was further validated using parametric and non-parametric methods. Aggregate differences in sex-specific genetic risk were examined by calculating a cumulative genetic risk score for SLE in each individual and comparing the average genetic risk between male and female patients. RESULTS A significantly higher cumulative genetic risk for SLE was observed in men than in women. (P=4.52x10-8) A significant sex-gene interaction was seen primarily in the human leucocyte antigen (HLA) region but also in IRF5, whereby men with SLE possess a significantly higher frequency of risk alleles than women. The genetic effect observed in KIAA1542 is specific to women with SLE and does not seem to have a role in men. CONCLUSIONS The data indicate that men require a higher cumulative genetic load than women to develop SLE. These observations suggest that sex bias in autoimmunity could be influenced by autosomal genetic susceptibility loci.
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Affiliation(s)
- Travis Hughes
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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17
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Sanchez E, Nadig A, Richardson BC, Freedman BI, Kaufman KM, Kelly JA, Niewold TB, Kamen DL, Gilkeson GS, Ziegler JT, Langefeld CD, Alarcón GS, Edberg JC, Ramsey-Goldman R, Petri M, Brown EE, Kimberly RP, Reveille JD, Vilá LM, Merrill JT, Anaya JM, James JA, Pons-Estel BA, Martin J, Park SY, Bang SY, Bae SC, Moser KL, Vyse TJ, Criswell LA, Gaffney PM, Tsao BP, Jacob CO, Harley JB, Alarcón-Riquelme ME, Sawalha AH. Phenotypic associations of genetic susceptibility loci in systemic lupus erythematosus. Ann Rheum Dis 2011; 70:1752-7. [PMID: 21719445 DOI: 10.1136/ard.2011.154104] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Systemic lupus erythematosus is a clinically heterogeneous autoimmune disease. A number of genetic loci that increase lupus susceptibility have been established. This study examines if these genetic loci also contribute to the clinical heterogeneity in lupus. MATERIALS AND METHODS 4001 European-derived, 1547 Hispanic, 1590 African-American and 1191 Asian lupus patients were genotyped for 16 confirmed lupus susceptibility loci. Ancestry informative markers were genotyped to calculate and adjust for admixture. The association between the risk allele in each locus was determined and compared in patients with and without the various clinical manifestations included in the ACR criteria. RESULTS Renal disorder was significantly correlated with the lupus risk allele in ITGAM (p=5.0 × 10(-6), OR 1.25, 95% CI 1.12 to 1.35) and in TNFSF4 (p=0.0013, OR 1.14, 95% CI 1.07 to 1.25). Other significant findings include the association between risk alleles in FCGR2A and malar rash (p=0.0031, OR 1.11, 95% CI 1.17 to 1.33), ITGAM and discoid rash (p=0.0020, OR 1.20, 95% CI 1.06 to 1.33), STAT4 and protection from oral ulcers (p=0.0027, OR 0.89, 95% CI 0.83 to 0.96) and IL21 and haematological disorder (p=0.0027, OR 1.13, 95% CI 1.04 to 1.22). All these associations are significant with a false discovery rate of <0.05 and pass the significance threshold using Bonferroni correction for multiple testing. CONCLUSION Signifi cant associations were found between clinical manifestations and the FCGR2A, ITGAM, STAT4, TNSF4 and IL21 genes. The findings suggest that genetic profiling might be a useful tool to predict disease manifestations in lupus patients in the future.
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Affiliation(s)
- Elena Sanchez
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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18
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Huang SK, Fisher AS, Scruggs AM, White ES, Hogaboam CM, Richardson BC, Peters-Golden M. Hypermethylation of PTGER2 confers prostaglandin E2 resistance in fibrotic fibroblasts from humans and mice. Am J Pathol 2010; 177:2245-55. [PMID: 20889571 DOI: 10.2353/ajpath.2010.100446] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease that is characterized by excessive proliferation of fibroblasts. The lipid mediator prostaglandin E2 (PGE2) has the capacity to limit fibrosis through its inhibition of numerous functions of these fibroblasts; however, in the setting of fibrosis, fibroblasts have been shown to be resistant to PGE2. We have linked such resistance to decreased expression levels of the E prostanoid 2 (EP2) receptor. In this study, in fibroblasts from both mice and humans with pulmonary fibrosis, we show that DNA hypermethylation is responsible for diminished EP2 expression levels and PGE2 resistance. Bisulfite sequencing of the prostaglandin E receptor 2 gene (PTGER2) promoter revealed that fibrotic fibroblasts exhibit greater PTGER2 methylation than nonfibrotic control cells. Treatment with the DNA methylation inhibitors 5-aza-2'-deoxycytidine and zebularine as well as DNA methyltransferase-specific siRNA decreased PTGER2 methylation, increased EP2 mRNA and protein expression levels, and restored PGE2 responsiveness in fibrotic fibroblasts but not in nonfibrotic controls. PTGER2 promoter hypermethylation was driven by an increase in Akt signal transduction. In addition to results described for the PTGER2 promoter, fibrotic fibroblasts also exhibited increased global DNA methylation. These findings demonstrate that the down-regulation of PTGER2 and consequent PGE2 resistance are both mediated by DNA hypermethylation; we identified increased Akt signal transduction as a novel mechanism that promotes DNA hypermethylation during fibrogenesis.
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Affiliation(s)
- Steven K Huang
- Department of Internal Medicine, University of Michigan Medical School, 6301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA.
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19
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Webb R, Kelly JA, Somers EC, Hughes T, Kaufman KM, Sanchez E, Nath SK, Bruner G, Alarcón-Riquelme ME, Gilkeson GS, Kamen DL, Richardson BC, Harley JB, Sawalha AH. Early disease onset is predicted by a higher genetic risk for lupus and is associated with a more severe phenotype in lupus patients. Ann Rheum Dis 2010; 70:151-6. [PMID: 20881011 DOI: 10.1136/ard.2010.141697] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Systemic lupus erythematosus (SLE) is a chronic, multiorgan, autoimmune disease that affects people of all ages and ethnicities. OBJECTIVES To explore the relationship between age at disease onset and many of the diverse manifestations of SLE. Additionally, to determine the relationship between age of disease onset and genetic risk in patients with SLE. METHODS The relationship between the age at disease onset and SLE manifestations were explored in a multi-racial cohort of 1317 patients. Patients with SLE were genotyped across 19 confirmed genetic susceptibility loci for SLE. Logistic regression was used to determine the relationships between the number of risk alleles present and age of disease onset. RESULTS Childhood-onset SLE had higher odds of proteinuria, malar rash, anti-dsDNA antibody, haemolytic anaemia, arthritis and leucopenia (OR=3.03, 2.13, 2.08, 2.50, 1.89, 1.53, respectively; p values <0.0001, 0.0004, 0.0005, 0.0024, 0.0114, 0.045, respectively). In female subjects, the odds of having cellular casts were 2.18 times higher in childhood-onset than in adult-onset SLE (p=0.0027). With age of onset ≥50, the odds of having proteinuria, cellular casts, anti-nRNP antibody, anti-Sm antibody, anti-dsDNA antibody and seizures were reduced. However, late adult-onset patients with SLE have higher odds of developing photosensitivity than early adult-onset patients. Each SLE-susceptibility risk allele carried within the genome of patients with SLE increased the odds of having a childhood-onset disease in a race-specific manner: by an average of 48% in Gullah and 25% in African-Americans, but this was not significant in Hispanic and European-American lupus patients. CONCLUSIONS The genetic contribution towards predicting early-onset disease in patients with SLE is quantified for the first time. A more severe SLE phenotype is found in patients with early-onset disease in a large multi-racial cohort, independent of gender, race and disease duration.
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Affiliation(s)
- Ryan Webb
- Arthritis & Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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20
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Wahl DR, Petersen B, Warner R, Richardson BC, Glick GD, Opipari AW. Characterization of the metabolic phenotype of chronically activated lymphocytes. Lupus 2010; 19:1492-501. [PMID: 20647250 DOI: 10.1177/0961203310373109] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Activated lymphocytes proliferate, secrete cytokines, and can make antibodies. Normally activated B and T cells meet the bioenergetic demand for these processes by up-regulating aerobic glycolysis. In contrast, several lines of evidence suggest that pathogenic lymphocytes in autoimmune diseases like lupus meet ATP demands through oxidative phosphorylation. Using (13)C-glucose as a stable tracer, we found that splenocytes from mice with lupus derive the same fraction of lactate from glucose as control animals, suggesting comparable levels of glycolysis and non-oxidative ATP production. However, lupus splenocytes increase glucose oxidation by 40% over healthy control animals. The ratio between pentose phosphate cycle (PPC) activity and glycolysis is the same for each group, indicating that increased glucose oxidation is due to increased activity of the TCA cycle in lupus splenocytes. Repetitive stimulation of cultured human T cells was used to model chronic lymphocyte activation, a phenotype associated with lupus. Chronically activated T cells rely primarily on oxidative metabolism for ATP synthesis suggesting that chronic antigen stimulation may be the basis for the metabolic findings observed in lupus mice. Identification of disease-related bioenergetic phenotypes should contribute to new diagnostic and therapeutic strategies for immune diseases.
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Affiliation(s)
- D R Wahl
- Chemical Biology Doctoral Program, University of Michigan, Ann Arbor, MI 48109, USA
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21
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Chen Y, Gorelik GJ, Strickland FM, Richardson BC. Decreased ERK and JNK signaling contribute to gene overexpression in "senescent" CD4+CD28- T cells through epigenetic mechanisms. J Leukoc Biol 2009; 87:137-45. [PMID: 19843577 DOI: 10.1189/jlb.0809562] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
An inflammatory and cytotoxic CD4+CD28- T cell subset infiltrates atherosclerotic plaques and is implicated in plaque rupture and myocardial infarctions. This pathologic subset develops with replicative stress and is found in patients with chronic inflammatory diseases such as RA as well as with aging. CD4+CD28- cells overexpress genes normally suppressed by DNA methylation in CD4+CD28+ T cells, such as KIR, perforin, and CD70. How this subset over expresses methylation-sensitive genes is unknown. DNA methylation patterns are maintained in proliferating cells by Dnmts, which are up-regulated during mitosis by the ERK and JNK signaling pathways. We hypothesized that defects in these signaling pathways contribute to altered gene expression in human CD4+CD28- cells through effects on DNA methylation. We report that signaling through the ERK and JNK pathways is decreased in CD4+CD28- relative to CD4+CD28+ cells from the same individuals and that ERK and JNK pathway inhibition decreases Dnmt1 and -3a levels, which in turn, causes demethylation and overexpression of the TNFSF7 (CD70) gene. We also report that CD4+CD28- T cells overexpress PP5, a stress-induced inhibitor of the ERK and JNK signaling pathways that may contribute to the signaling defects. We conclude that decreased ERK and JNK signaling in the CD4+CD28- subset, arising with replicative stress, can lead to the overexpression of normally suppressed genes through effects on Dnmts and consequently, chromatin structure.
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Affiliation(s)
- Yingxuan Chen
- Department of Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA
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22
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Basu D, Liu Y, Wu A, Yarlagadda S, Gorelik GJ, Kaplan MJ, Hewagama A, Hinderer RC, Strickland FM, Richardson BC. Stimulatory and inhibitory killer Ig-like receptor molecules are expressed and functional on lupus T cells. J Immunol 2009; 183:3481-7. [PMID: 19675166 DOI: 10.4049/jimmunol.0900034] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cells from lupus patients have hypomethylated DNA and overexpress genes normally suppressed by DNA methylation that contribute to disease pathogenesis. We found that stimulatory and inhibitory killer cell Ig-like receptor (KIR) genes are aberrantly overexpressed on experimentally demethylated T cells. We therefore asked if lupus T cells also overexpress KIR, and if the proteins are functional. T cells from lupus patients were found to overexpress KIR genes, and expression was proportional to disease activity. Abs to the stimulatory molecule KIR2DL4 triggered IFN-gamma release by lupus T cells, and production was proportional to disease activity. Similarly, cross-linking the inhibitory molecule KIR3DL1 prevented the autoreactive macrophage killing that characterizes lupus T cells. These results indicate that aberrant T cell KIR expression may contribute to IFN overproduction and macrophage killing in human lupus, and they suggest that Abs to inhibitory KIR may be a treatment for this disease.
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Affiliation(s)
- Dhiman Basu
- Department of Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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23
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Ray D, Richardson BC. Diet and DNA methylation in lupus (50.29). The Journal of Immunology 2009. [DOI: 10.4049/jimmunol.182.supp.50.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
T cell DNA demethylation contributes to human lupus. The mechanisms causing demethylation are incompletely understood. DNA methylation depends on DNA methyltransferase activity and S-adenosylmethionine (SAM), and is inhibited by S-adenosylhomocysteine (SAH). SAM levels are determined by Zn, B2, B6, B12, folate, Met and choline, and SAH by homocysteine (Hcy). We hypothesized that decreasing nutrients required for SAM or increasing Hcy increases expression of methylation sensitive T cell genes, and that levels of these nutrients are abnormal in lupus patients. PHA stimulated T cells were cultured in custom media with variable concentrations of each nutrient, and effects on methylation sensitive gene expression (CD70, KIR and perforin) compared by flow cytometry. T cells cultured in media adjusted to median serum levels of each nutrient overexpressed all methylation sensitive genes relative to complete media. Increasing Hcy caused further increases in CD70 while increasing folate or B6 concentrations suppressed perforin overexpression. Lupus patients had lower B6 and Zn levels, and higher Hcy levels than controls. These results suggest that a poor diet may contribute to abnormal T cell gene expression in lupus, and that dietary supplementation may have a beneficial effect.
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Affiliation(s)
- Donna Ray
- 1University of Michigan, Ann Arbor, MI
| | - Bruce C Richardson
- 1University of Michigan, Ann Arbor, MI
- 2VA Ann Arbor Health System, Ann Arbor, MI
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24
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Hewagama A, Patel D, Yarlagadda S, Strickland FM, Richardson BC. Stronger inflammatory/cytotoxic T-cell response in women identified by microarray analysis. Genes Immun 2009; 10:509-16. [PMID: 19279650 PMCID: PMC2735332 DOI: 10.1038/gene.2009.12] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Women develop chronic inflammatory autoimmune diseases more often than men. The mechanisms causing the increased susceptibility are incompletely understood. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T cell response in women than men. Microarrays were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days following a single stimulation only 25% of differentially expressed, gender-biased genes were expressed at higher levels in women. In contrast, following restimulation 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women and among the immune response genes, the inflammatory/cytotoxic effector genes interferon gamma (IFNG), lymphotoxin beta (LTB), granzyme A (GZMA), interleukin-12 receptor beta2 (IL12RB2), and granulysin (GNLY) were among those overexpressed to the greatest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half the overexpressed immune genes in women, and in <10% of the male biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men.
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Affiliation(s)
- A Hewagama
- Department of Internal Medicine, Rheumatology Division, The University of Michigan, Ann Arbor, MI 48109-2200, USA
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25
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Strickland FM, Richardson BC. Epigenetics in human autoimmunity. Epigenetics in autoimmunity - DNA methylation in systemic lupus erythematosus and beyond. Autoimmunity 2008; 41:278-86. [PMID: 18432408 DOI: 10.1080/08916930802024616] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epigenetic mechanisms are essential for normal development and function of the immune system. Similarly, a failure to maintain epigenetic homeostasis in the immune response due to factors including environmental influences, leads to aberrant gene expression, contributing to immune dysfunction and in some cases the development of autoimmunity in genetically predisposed individuals. This is exemplified by systemic lupus erythematosus, where environmentally induced epigenetic changes contribute to disease pathogenesis in those genetically predisposed. Similar interactions between genetically determined susceptibility and environmental factors are implicated in other systemic autoimmune diseases such as rheumatoid arthritis and scleroderma, as well as in organ specific autoimmunity. The skin is exposed to a wide variety of environmental agents, including UV radiation, and is prone to the development of autoimmune conditions such as atopic dermatitis, psoriasis and some forms of vitiligo, depending on environmental and genetic influences. Herein we review how disruption of epigenetic mechanisms can alter immune function using lupus as an example, and summarize how similar mechanisms may contribute to other human autoimmune rheumatic and skin diseases.
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Affiliation(s)
- Faith M Strickland
- The Department of Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA.
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26
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Affiliation(s)
- Bruce C Richardson
- The Department of Medicine, University of Michigan, 3018 BSRB, 109 Zina Pitcher Pl, Ann Arbor, MI 48109-2200, USA.
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27
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Cooper GS, Gilbert KM, Greidinger EL, James JA, Pfau JC, Reinlib L, Richardson BC, Rose NR. Recent advances and opportunities in research on lupus: environmental influences and mechanisms of disease. Environ Health Perspect 2008; 116:695-702. [PMID: 18560522 PMCID: PMC2430222 DOI: 10.1289/ehp.11092] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/05/2008] [Indexed: 05/26/2023]
Abstract
OBJECTIVES In this review we summarize research on mechanisms through which environmental agents may affect the pathogenesis of lupus, discuss three exposures that have been the focus of research in this area, and propose recommendations for new research initiatives. DATA SOURCES AND SYNTHESIS We examined studies pertaining to key mechanistic events and specific exposures. Apoptosis leading to increased production or decreased clearance of immunogenic intracellular self-antigens and defective apoptosis of autoreactive immune cells both have been implicated in the loss of self-tolerance. The adjuvant or bystander effect is also needed to produce a sustained autoimmune response. Activation of toll-like receptors is one mechanism through which these effects may occur. Abnormal DNA methylation may also contribute to the pathogenesis of lupus. Each of the specific exposures we examined--Epstein-Barr virus, silica, and trichloroethylene--has been shown, in humans or in mice, to act upon one or more of these pathogenic steps. Specific recommendations for the continued advancement of our understanding of environmental influences on lupus and other autoimmune diseases include the development and use of mouse models with varying degrees of penetrance and manifestations of disease, identification of molecular or physiologic targets of specific exposures, development and use of improved exposure assessment methodologies, and multisite collaborations designed to examine understudied environmental exposures in humans. CONCLUSIONS The advances made in the past decade concerning our understanding of mechanisms involved in the development of lupus and the influence of environmental agents on this process provide a strong foundation for further developments in this field.
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Affiliation(s)
- Glinda S Cooper
- National Center for Environmental Assessment, US Environmental Protection Agency, Washington, DC 20460, USA.
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28
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Hewagama A, Patel D, Yarlagadda S, Strickland FM, Richardson BC. Evaluation of gender differences in methylation‐sensitive immune gene expression in T cells by cDNA microarray. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.825.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Dipak Patel
- Division RheumatologyUniversity of MichiganAnn ArborMI
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29
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Lu Q, Qiu X, Hu N, Wen H, Su Y, Richardson BC. Epigenetics, disease, and therapeutic interventions. Ageing Res Rev 2006; 5:449-67. [PMID: 16965942 DOI: 10.1016/j.arr.2006.07.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 07/20/2006] [Accepted: 07/24/2006] [Indexed: 12/13/2022]
Abstract
Heritable changes in gene expression that do not involve coding sequence modifications are referred to as "epigenetic". Epigenetic mechanisms principally include DNA methylation and a variety of histone modifications, of which the best characterized is acetylation. DNA hypermethylation and histone hypoacetylation are hallmarks of gene silencing, while DNA hypomethylation and acetylated histones promote active transcription. Aberrant DNA methylation and histone acetylation have been linked to a number of age related disorders including cancer, autoimmune disorders and others. Since epigenetic alterations are reversible, modifying epigenetic marks contributing to disease development may provide an approach to designing new therapies. Herein we review the role of epigenetic changes in disease development, and recent advances in the therapeutic modification of epigenetic marks.
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Affiliation(s)
- Q Lu
- Department of Dermatology and Epigenetic Research Center, Second Xiangya Hospital, Central South University, Hunan 410011, PR China
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30
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Abstract
Systemic lupus erythematosus (SLE) is an archetypical systemic, autoimmune inflammatory disease characterized by the production of autoantibodies to multiple nuclear Ags. Apoptotic defects and impaired removal of apoptotic cells contribute to an overload of autoantigens that become available to initiate an autoimmune response. Besides the well-recognized genetic susceptibility to SLE, epigenetic factors are important in the onset of the disease, as even monozygotic twins are usually discordant for the disease. Changes in DNA methylation and histone modifications, the major epigenetic marks, are a hallmark in genes that undergo epigenetic deregulation in disease. In SLE, global and gene-specific DNA methylation changes have been demonstrated to occur. Moreover, histone deacetylase inhibitors reverse the skewed expression of multiple genes involved in SLE. In the present study, we discuss the implications of epigenetic alterations in the development and progression of SLE and how epigenetic drugs constitute a promising source of therapy to treat this disease.
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Affiliation(s)
- Esteban Ballestar
- Cancer Epigenetics Laboratory, Molecular Pathology Programme, Spanish National Cancer Centre (CNIO), Madrid, Spain.
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Denny MF, Chandaroy P, Killen PD, Caricchio R, Lewis EE, Richardson BC, Lee KD, Gavalchin J, Kaplan MJ. Accelerated macrophage apoptosis induces autoantibody formation and organ damage in systemic lupus erythematosus. J Immunol 2006; 176:2095-104. [PMID: 16455965 DOI: 10.4049/jimmunol.176.4.2095] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increased monocyte/macrophage (Mphi) apoptosis occurs in patients with systemic lupus erythematosus (SLE) and is mediated, at least in part, by an autoreactive CD4(+) T cell subset. Furthermore, autoreactive murine CD4(+) T cells that kill syngeneic Mphi in vitro induce a lupus-like disease in vivo. However, it is unclear whether increased Mphi apoptosis in SLE per se is sufficient to accelerate/promote autoimmunity. We have investigated whether increased Mphi apoptosis in vivo, induced by the administration of clodronate liposomes, can exacerbate the autoimmune phenotype in NZB x SWR (SNF(1)) lupus-prone mice, and induce autoantibody production in haplotype-matched BALB/c x DBA1 (DBF(1)) non-lupus-prone mice. Lupus-prone mice SNF(1) mice that were treated with clodronate liposomes, but not mice treated with vehicle, developed significant increases in autoantibodies to dsDNA, nucleosomes, and the idiotypically related family of nephritic Abs Id(LN)F(1), when compared with untreated SNF(1) mice. Furthermore, clodronate treatment hastened the onset of proteinuria and worsened SNF(1) lupus nephritis. When compared with vehicle-treated controls, clodronate-treated non-lupus-prone DBF(1) mice developed significantly higher levels of anti-nucleosome and Id(LN)F(1) Abs but did not develop lupus nephritis. We propose that Mphi apoptosis contributes to the pathogenesis of autoantibody formation and organ damage through both an increase in the apoptotic load and impairment in the clearance of apoptotic material. This study suggests that mechanisms that induce scavenger cell apoptosis, such as death induced by autoreactive cytotoxic T cells observed in SLE, could play a pathogenic role and contribute to the severity of the disease.
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Affiliation(s)
- Michael F Denny
- Department of Internal Medicine, University of Michigan, Ann Arbor, 48109, USA
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32
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Abstract
Estrogen has been implicated in the observed female bias in autoimmune diseases. However, the mechanisms behind this gender dimorphism are poorly defined. We have previously reported that in vivo T cell trafficking is gender- and estrogen-dependent. Chemokine receptors are critical determinants of T cell homing and immune response. In this study, we show that the female gender is associated with increased CD4(+) T cell CCR1-CCR5 gene and protein expression in mice. The increased CCR expression correlates with enhanced in vitro chemotaxis response to MIP-1beta (CCL4). In vivo treatment of young oophorectomized and postmenopausal female mice with 17beta-estradiol also increased CD4(+) T cell CCR expression. Finally, 17beta-estradiol enhances tyrosine phosphorylation in T cells stimulated with MIP-1alpha in a time-dependent manner. Our results indicate an important role of estrogen in determining T cell chemokine response that may help explain the increased susceptibility and severity of autoimmune diseases in females.
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MESH Headings
- Animals
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Cell Line
- Chemokine CCL3
- Chemokine CCL4
- Chemokine CXCL12
- Chemokines, CC/metabolism
- Chemokines, CXC/pharmacology
- Chemotaxis, Leukocyte/immunology
- Estrogens/administration & dosage
- Estrogens/physiology
- Female
- Gene Expression Regulation/immunology
- Macrophage Inflammatory Proteins/pharmacology
- Male
- Mice
- Mice, Inbred AKR
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Ovariectomy
- Receptors, CCR4
- Receptors, CCR5/biosynthesis
- Receptors, CCR5/genetics
- Receptors, CCR5/physiology
- Receptors, Chemokine/biosynthesis
- Receptors, Chemokine/genetics
- Receptors, Chemokine/physiology
- Sex Characteristics
- Species Specificity
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- RuRan Mo
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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33
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Lu Q, Wu A, Richardson BC. Demethylation of the same promoter sequence increases CD70 expression in lupus T cells and T cells treated with lupus-inducing drugs. J Immunol 2005; 174:6212-9. [PMID: 15879118 DOI: 10.4049/jimmunol.174.10.6212] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exposing genetically predisposed individuals to certain environmental agents is believed to cause human lupus. How environmental agents interact with the host to cause lupus is poorly understood. Procainamide and hydralazine are drugs that cause lupus in genetically predisposed individuals. Understanding how these environmental agents cause lupus may indicate mechanisms relevant to the idiopathic disease. Abnormal T cell DNA methylation, a repressive epigenetic DNA modification, is implicated in procainamide and hydralazine induced lupus, as well as idiopathic lupus. Procainamide is a competitive DNA methyltransferase (Dnmt) inhibitor, hydralazine inhibits ERK pathway signaling thereby decreasing Dnmt expression, and in lupus T cells decreased ERK pathway signaling causing a similar Dnmt decrease. T cells treated with procainamide, hydralazine, and other Dnmt and ERK pathway inhibitors cause lupus in mice. Whether the same genetic regulatory elements demethylate in T cells treated with Dnmt inhibitors, ERK pathway inhibitors, and in human lupus is unknown. CD70 (TNFSF7) is a B cell costimulatory molecule overexpressed on CD4(+) lupus T cells as well as procainamide and hydralazine treated T cells, and contributes to excessive B cell stimulation in vitro and in lupus. In this report we identify a genetic element that suppresses CD70 expression when methylated, and which demethylates in lupus and in T cells treated with Dnmt and ERK pathway inhibitors including procainamide and hydralazine. The results support a model in which demethylation of specific genetic elements in T cells, caused by decreasing Dnmt expression or inhibiting its function, contributes to drug-induced and idiopathic lupus through altered gene expression.
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MESH Headings
- 5' Flanking Region/drug effects
- Adult
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Base Sequence
- CD27 Ligand
- Cells, Cultured
- DNA Methylation/drug effects
- Enzyme Inhibitors/pharmacology
- Female
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/immunology
- Humans
- Hydralazine/pharmacology
- Jurkat Cells
- Lupus Erythematosus, Systemic/chemically induced
- Lupus Erythematosus, Systemic/genetics
- Lupus Erythematosus, Systemic/immunology
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Middle Aged
- Molecular Sequence Data
- Procainamide/pharmacology
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/immunology
- RNA, Messenger/biosynthesis
- T-Lymphocyte Subsets/drug effects
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
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Affiliation(s)
- Qianjin Lu
- Department of Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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Murphy HS, Sun Q, Murphy BA, Mo R, Huo J, Chen J, Chensue SW, Adams M, Richardson BC, Yung R. Tissue-specific effect of estradiol on endothelial cell-dependent lymphocyte recruitment. Microvasc Res 2004; 68:273-85. [PMID: 15501247 DOI: 10.1016/j.mvr.2004.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Indexed: 02/02/2023]
Abstract
Estrogen profoundly affects onset and severity of many immune-mediated diseases. In our murine model of drug-induced autoimmunity, female-specific, estrogen-dependent increase in splenic lymphocyte homing was directly implicated in increased disease severity. The present study evaluated the effect of estradiol on microvascular endothelial cells from the spleen compared to endothelial cells from the dermis, which has no disease manifestation in this model. Estradiol increased spleen endothelial cell estrogen receptor (ER) alpha 2.9-fold and decreased estrogen receptor beta 2.1-fold while decreasing both receptors on dermal cells. Estradiol enhanced adhesion of D10 cells to spleen but not dermal endothelial cells 1.53-fold (P < 0.001), an increase that was inhibited by antibodies to VCAM-1 and ICAM-1, and by the estrogen receptor antagonists tamoxifen and ICI 182,780. Estradiol induced greater VCAM-1 expression on spleen than dermal endothelial cells (P < 0.05). Estradiol increased spleen endothelial cell estrogen receptor alpha 2.9-fold and decreased estrogen receptor beta 2.1-fold while decreasing both receptors on the dermal cells. Estrogen specifically and preferentially promoted spleen chemokine protein expression for MCP-1 and MCP-3, while having no effect on dermal protein expression for these chemokines. Estradiol-mediated effects on splenic chemokines were abrogated by tamoxifen and ICI 182,780. The gender-specific increase in lymphocyte homing to spleen may be attributable, at least in part, to tissue-specific estrogen-mediated effects on microvascular endothelial cells.
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Affiliation(s)
- Hedwig S Murphy
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA.
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35
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Rajagopalan S, Somers EC, Brook RD, Kehrer C, Pfenninger D, Lewis E, Chakrabarti A, Richardson BC, Shelden E, McCune WJ, Kaplan MJ. Endothelial cell apoptosis in systemic lupus erythematosus: a common pathway for abnormal vascular function and thrombosis propensity. Blood 2004; 103:3677-83. [PMID: 14726373 DOI: 10.1182/blood-2003-09-3198] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractWomen with systemic lupus erythematosus (SLE) are at risk for premature atherothrombosis independent of Framingham risk factors. We investigated whether endothelial cell (EC) apoptosis predicts abnormal vasomotor tone and contributes to circulating tissue factor (TF) levels in this disease. Brachial artery flow-mediated dilation (FMD) and nitroglycerin-mediated dilation were determined in women with SLE, healthy control subjects, and subjects with coronary artery disease (CAD) (n = 43/group). Quantification of circulating apoptotic ECs was performed by flow cytometry (CD146+ cells that stained for Annexin V [CD146AnnV+]) and immunofluorescent microscopy. Plasma TF was measured by enzyme-linked immunosorbent assay (ELISA). Compared with healthy control and CAD subjects, patients with SLE had higher numbers of circulating CD146AnnV+ cells (10 ± 3, 18 ± 5, and 89 ± 32 cells/mL, respectively, mean ± SEM; P < .01). Increased CD146AnnV+ cells correlated strongly with abnormal vascular function (P = .037). After adjusting for known predictors of endothelial function, CD146AnnV+ was the only variable that predicted FMD (β = –4.5, P < .001). Increased CD146AnnV+ was strongly associated with elevated levels of circulating TF (r = .46, P = .002). Circulating apoptotic ECs are elevated in young women with SLE and strongly correlate with markedly abnormal vascular function and elevated TF levels. Heightened endothelial apoptosis may represent an important mechanism for development of atherothrombosis in SLE.
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Affiliation(s)
- Sanjay Rajagopalan
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-0680, USA
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36
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Bednarski JJ, Warner RE, Rao T, Leonetti F, Yung R, Richardson BC, Johnson KJ, Ellman JA, Opipari AW, Glick GD. Attenuation of autoimmune disease in Fas-deficient mice by treatment with a cytotoxic benzodiazepine. Arthritis Rheum 2003; 48:757-66. [PMID: 12632430 DOI: 10.1002/art.10968] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Elimination of autoreactive cells relies on Fas-dependent activation-induced cell death mechanisms, an important component of peripheral tolerance. Defects in Fas or its cognate ligand lead to inefficient activation-induced cell death and are specific causes of lymphoproliferative and autoimmune diseases. The present study was undertaken to investigate a novel 1,4-benzodiazepine (Bz-423) that induces apoptosis and limits autoimmune disease in NZB/NZW mice, to determine its activity against lupus-like disease associated with defective Fas expression. We investigated the Fas-dependence of its cytotoxic actions, its therapeutic potential in mice deficient in Fas, and its therapeutic mechanism of action. METHODS Primary lymphocytes isolated from Fas-deficient MRL/MpJ-Fas(lpr) (MRL-lpr) mice were tested for sensitivity to Bz-423. Bz-423 was administered to MRL-lpr mice for short (1-week) or long (14-week) periods, and its effects on cell survival were determined along with measures of nephritis, arthritis, antibody titers, and Th subpopulations. BALB/c mice were similarly treated to determine if Bz-423 alters normal immune functions in vivo. RESULTS Administration of Bz-423 to MRL-lpr mice significantly reduced autoimmune disease including glomerulonephritis and arthritis. Treatment was associated with decreases in CD4+ T cells and an alteration in the Th1/Th2 balance. At the therapeutic dosage, Bz-423 did not interfere with normal T and B cell responses in BALB/c mice, suggesting that this agent is not globally immunosuppressive. CONCLUSION Bz-423 is a novel immunomodulatory agent that is active against disease even in the context of defective Fas signaling. It is a leading compound for further investigation into the development of selective therapies for lupus.
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Kaplan MJ, Lewis EE, Shelden EA, Somers E, Pavlic R, McCune WJ, Richardson BC. The apoptotic ligands TRAIL, TWEAK, and Fas ligand mediate monocyte death induced by autologous lupus T cells. J Immunol 2002; 169:6020-9. [PMID: 12421989 DOI: 10.4049/jimmunol.169.10.6020] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Individuals with systemic lupus erythematosus show evidence of a significant increase in monocyte apoptosis. This process is mediated, at least in part, by an autoreactive T cell subset that kills autologous monocytes in the absence of nominal Ag. We have investigated the apoptotic pathways involved in this T cell-mediated process. Expression of the apoptotic ligands TRAIL, TNF-like weak inducer of apoptosis (TWEAK), and Fas ligand on lupus T cells was determined, and the role of these molecules in the monocyte apoptotic response was examined. We report that these apoptotic ligands mediate the autologous monocyte death induced by lupus T cells and that this cytotoxicity is associated with increased expression of these molecules on activated T cells, rather than with an increased susceptibility of lupus monocytes to apoptosis induced by these ligands. These results define novel mechanisms that contribute to increased monocyte apoptosis characterizing patients with lupus. We propose that this mechanism could provide a source of potentially antigenic material for the autoimmune response and interfere with normal clearing mechanisms.
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Affiliation(s)
- Mariana J Kaplan
- Department of Internal Medicine, University of Michigan, 1150 West Medical Center Drive, 5220 Medical Science Research Building I, Ann Arbor, MI 48109, USA.
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Hale TJ, Richardson BC, Sweet LI, McElligott DL, Riggs JE, Chu EB, Glynn JM, LaFrenz D, Ernst DN, Rochford R, Hobbs MV. Age-related changes in mature CD4+ T cells: cell cycle analysis. Cell Immunol 2002; 220:51-62. [PMID: 12718939 DOI: 10.1016/s0008-8749(03)00007-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
T cell proliferative responses decrease with age, but the mechanisms responsible are unknown. We examined the impact of age on memory and naive CD4(+) T cell entry and progression through the cell cycle using acridine orange to identify cell cycle stage. For both subsets, fewer stimulated cells from old donors were able to enter and progress through the first cell cycle, with an increased number of cells arrested in G(0) and fewer cells in post G(0) phases. The number of dead cells as assessed by sub-G(0) DNA was also significantly greater in the old group. CD4(+) T cells from old mice also exhibited a significant reduction in clonal history as assessed by CFSE staining. This was associated with a significant decline in cyclin D2 mRNA and protein. We propose that decreases in cyclin D2 are at least partially responsible for the proliferative decline found in aged CD4(+) T cells.
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Affiliation(s)
- Timothy J Hale
- Department of Epidemiology, University of Michigan, Ann Arbor, MI 48109-0940, USA
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39
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Blatt NB, Bednarski JJ, Warner RE, Leonetti F, Johnson KM, Boitano A, Yung R, Richardson BC, Johnson KJ, Ellman JA, Opipari AW, Glick GD. Benzodiazepine-induced superoxide signals B cell apoptosis: mechanistic insight and potential therapeutic utility. J Clin Invest 2002; 110:1123-32. [PMID: 12393848 PMCID: PMC150800 DOI: 10.1172/jci16029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The properties of a proapoptotic 1,4-benzodiazepine, Bz-423, identified through combinatorial chemistry and phenotype screening are described. Bz-423 rapidly generated superoxide (O(2)(-)) in transformed Ramos B cells. This O(2)(-) response originated from mitochondria prior to mitochondrial transmembrane gradient collapse and opening of the permeability transition pore. Bz-423-induced O(2)(-) functioned as an upstream signal that initiated an apoptotic program characterized by cytochrome c release, mitochondrial depolarization, and caspase activation. Pretreatment of cells with agents that either block the formation of Bz-423-induced O(2)(-) or scavenge free radicals attenuated the death cascade, which demonstrated that cell killing by Bz-423 depends on O(2)(-). Parallels between Ramos cells and germinal center B cells prompted experiments to determine whether Bz-423 had therapeutic activity in vivo. This possibility was tested using the (NZB x NZW)F(1) murine model of lupus, in which the pathologically enhanced survival and expansion of germinal center B cells mediate disease. Administration of Bz-423 for 12 weeks specifically controlled germinal center hyperplasia and reduced the histological evidence of glomerulonephritis. Collectively, these studies define a new structure-function relationship for benzodiazepines and point to a new target and mechanism that could be of value for developing improved drugs to manage systemic lupus erythematosus and related disorders.
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Affiliation(s)
- Neal B Blatt
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, USA
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40
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Blatt NB, Bednarski JJ, Warner RE, Leonetti F, Johnson KM, Boitano A, Yung R, Richardson BC, Johnson KJ, Ellman JA, Opipari AW, Glick GD. Benzodiazepine-induced superoxide signalsB cell apoptosis: mechanistic insight and potential therapeutic utility. J Clin Invest 2002. [DOI: 10.1172/jci0216029] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
DNA methylation plays an essential role in maintaining cellular function, and changes in methylation patterns may contribute to the development of autoimmunity, aging and cancer. Evidence for a role in autoimmunity comes from studies demonstrating that inhibiting T lymphocyte DNA methylation causes autoreactivity in vitro and a lupus-like disease in vivo. The autoimmunity is due in part to the heterodimeric beta(2) integrin lymphocyte function-associated antigen-1 (LFA-1) (CD11a/CD18) overexpression, and T lymphocytes from lupus patients hypomethylate the same CD11a promoter sequences, overexpress LFA-1 and demonstrate the same autoreactivity. Procainamide and hydralazine, two drugs that cause a lupus-like disease, also inhibit T cell DNA methylation, increase LFA-1 expression and induce autoreactivity in vitro and autoimmunity in vivo, supporting the association of DNA hypomethylation and autoimmunity. Methylation patterns also change with age in T lymphocytes as well as other tissues, typically with an overall decrease in methylcytosine content, but with increases in some cytosine guanine dinucleotide (CpG) islands. Age-dependent hypomethylation contributes to LFA-1 overexpression with aging, which may play a role in the development of autoimmunity in the elderly and age-dependent methylation of CpG islands in the promoters of tumor suppressor genes is an early event in the development of some cancers. DNA hypomethylation also may contribute to carcinogenesis by promoting overexpression of proto-oncogenes, chromosomal translocations and loss of imprinting. The mechanisms causing altered DNA methylation in autoimmunity, aging and carcinogenesis are incompletely characterized but include exposure to environmental agents and drugs, diet, altered signaling in pathways regulating DNA methyltransferase expression and changes in endogenous regulatory mechanisms. Other mechanisms are likely to be identified as well.
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Affiliation(s)
- Bruce C Richardson
- Department of Medicine, University of Michigan and the Veterans Affairs Hospital, Ann Arbor 48109-0940, USA.
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Affiliation(s)
- Gary M Kammer
- Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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Abstract
The regulation of gene transcription is not simply dependent on the presence or absence of DNA-binding transcription factors that turn genes on or off, but also involves processes determining the ability of transcription factors to gain access to and bind their target DNA. Methylation of DNA cytosine bases leads to the inaccessibility of DNA regulatory elements to their transcription factors by a number of mechanisms. Our understanding of DNA methylation has advanced rapidly in recent years with the identification of an increasingly large number of novel proteins involved in this process. These include methylcytosine-binding proteins as well as additional members of the DNA methyltransferase family. The creation of mice with targeted deletions in a number of genes involved in DNA methylation has further elucidated the functions of many of these proteins. The characterization of complexes that contain proteins known to be involved in DNA methylation has led to the identification of additional proteins, especially those involved in histone deacetylation, indicating that DNA methylation and histone deacetylation very likely act in a synergistic fashion to regulate gene transcription. Finally, the implication of DNA methylation in tumorigenesis and the realization that some congenital diseases are caused by deficiency of proteins involved in DNA methylation has confirmed the importance of this process in regulating gene expression.
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Affiliation(s)
- J T Attwood
- Department of Internal Medicine, University of Michigan, Taubman Center, Ann Arbor 48109, USA
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44
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Deng C, Kaplan MJ, Yang J, Ray D, Zhang Z, McCune WJ, Hanash SM, Richardson BC. Decreased Ras-mitogen-activated protein kinase signaling may cause DNA hypomethylation in T lymphocytes from lupus patients. Arthritis Rheum 2001; 44:397-407. [PMID: 11229472 DOI: 10.1002/1529-0131(200102)44:2<397::aid-anr59>3.0.co;2-n] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Previous studies have shown that inhibiting T cell DNA methylation causes a lupus-like disease by modifying gene expression. T cells from patients with lupus exhibit diminished levels of DNA methyltransferase (MTase) enzyme activity, hypomethylated DNA, and changes in gene expression similar to those exhibited by T cells treated with methylation inhibitors, suggesting that DNA hypomethylation may contribute to human lupus. Since it is known that DNA MTase levels are regulated by the ras-mitogen-activated protein kinase (MAPK) pathway, this study sought to determine whether decreased ras-MAPK signaling could account for the DNA hypomethylation in lupus T cells. METHODS DNA MTase messenger RNA (mRNA) from lupus patients and from healthy controls was quantitated by Northern analysis, and ras-MAPK signaling was determined by immunoblotting with antibodies to the activated forms of extracellular receptor-associated kinase (ERK). Results were compared with those in T cells in which ras-MAPK signaling was inhibited with a soluble inhibitor of MAPK ERK I (MEK1). RESULTS T cells from patients with active lupus had diminished DNA MTase mRNA levels and decreased signaling through the ras-MAPK pathway. Inhibiting signaling through the ras-MAPK pathway with the MEK1 inhibitor decreased DNA MTase mRNA and enzyme activity to the levels seen in lupus T cells, and resulted in DNA hypomethylation resembling that seen in lupus T cells. CONCLUSION These results suggest that a decrease in signaling through the ras-MAPK pathway may be responsible for the decreased MTase activity and DNA hypomethylation in patients with lupus.
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Affiliation(s)
- C Deng
- University of Michigan and the Ann Arbor VA Hospital, USA
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45
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Kaplan MJ, Beretta L, Yung RL, Richardson BC. LFA-1 overexpression and T cell autoreactivity: mechanisms. Immunol Invest 2000; 29:427-42. [PMID: 11130784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Overexpressing LFA-1 (CD11a/CD18) on antigen specific CD4+ T cells makes the cells proliferate to normally subthreshold stimuli, including self-Ia molecules without specific antigen. The mechanisms by which this occurs are unknown, but potentially include transmission of an increased costimulatory signal, overstabilization of normally low affinity TCR-Ia interactions, or both. A role for increased costimulatory signaling was tested by culturing control and CD18-transfected antigen-specific T cells clones with anti-CD3 and anti-CD11a. Minimal calcium fluxes were detected, but increased protein tyrosine phosphorylation was observed in the transfectants. However, the proliferative response to graded amounts of these antibodies were identical in the transfectants and controls, suggesting that increased signaling alone was insufficient to cause the increased responsiveness. To test for overstabilization, transfected and control clones were cultured with syngeneic Mø with or without antigen. The transfected but not control cells downregulated TCR expression in response to Mø alone, thus demonstrating successful TCR signaling to a low affinity interaction. These results indicate that LFA-1 overexpression permits TCR signal transmission to a normally subthreshold stimulus presented by Mø, consistent with overstabilization. LFA-1 overexpression also causes increased tyrosine phosphorylation, but this alone is not sufficient to cause a proliferative response to low level stimuli.
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Affiliation(s)
- M J Kaplan
- Dept. of Medicine, University of Michigan, Ann Arbor 48109, USA
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46
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Kaplan MJ, Deng C, Yang J, Richardson BC. DNA methylation in the regulation of T cell LFA-1 expression. Immunol Invest 2000; 29:411-25. [PMID: 11130783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Inducing T cell LFA-1 overexpression by transfection, or by treatment with DNA methylation inhibitors including 5-azacytidine, procainamide and hydralazine, causes MHC-specific T cell autoreactivity in vitro and autoimmunity in vivo. How DNA methylation inhibitors increase LFA-1 expression is unknown. In this report we identify a mechanism by which DNA methylation affects LFA-1 expression. Nuclear run-on assays demonstrated that inhibiting DNA methylation increased transcription of CD11a but not CD18 or beta-actin mRNA. CD11a mRNA stability was not affected. Transfection of hypomethylated cells with reporter constructs containing the CD11a promoter showed no role for overexpression of transcription factors. However, the CD11a promoter demethylated following treatment with DNA methyltransferase inhibitors, and in vitro methylation of the construct suppressed its expression. Together, these results indicate that DNA methylation inhibitors can cause LFA-1 overexpression directly by demethylating the CD11a promoter. This mechanism could contribute to T cell autoreactivity, and potentially to autoimmunity.
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Affiliation(s)
- M J Kaplan
- Department of Internal Medicine, University of Michigan, Ann Arbor 48109, USA
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Kaplan MJ, Ray D, Mo RR, Yung RL, Richardson BC. TRAIL (Apo2 ligand) and TWEAK (Apo3 ligand) mediate CD4+ T cell killing of antigen-presenting macrophages. J Immunol 2000; 164:2897-904. [PMID: 10706675 DOI: 10.4049/jimmunol.164.6.2897] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The human marrow produces approximately 1010 monocytes daily, and this production must be balanced by a similar rate of destruction. Monocytes/macrophages can undergo apoptosis after activating CD4+ T cells, suggesting one mechanism that may contribute to macrophage homeostasis. Previous reports indicate that Fas-Fas ligand interactions are the principle molecules mediating this response. However, D10, an Iak-restricted cloned Th2 line, will similarly induce apoptosis in Ag-presenting macrophages, and D10 cells lack Fas ligand. To confirm that D10 cells kill macrophages through Fas-independent pathways, D10 cells were shown to kill MRL lpr/lpr (Iak) macrophages in an Ag-dependent fashion, indicating additional mechanisms. Recent reports demonstrate that TNF-related apoptosis-inducing ligand (TRAIL), interacting with Apo2, and TNF-like weak inducer of apoptosis (TWEAK), interacting with Apo3, will induce apoptosis in some cells. Using Abs to TRAIL and an Apo3-IgG Fc fusion protein, we demonstrated that D10 cells express both TRAIL and TWEAK. The Apo3 fusion protein, but not human IgG, inhibited D10-induced macrophage apoptosis, as did anti-TRAIL. Further studies demonstrated that AE7, a cloned Th1 line, and splenic T cells express TWEAK, TRAIL, and Fas ligand, and inhibiting these molecules also inhibited macrophage killing. These results indicate that D10 cells induce macrophage apoptosis through TRAIL- and TWEAK-dependent pathways. Because normal T cells also express these molecules, these results support the concept that T cells have multiple pathways by which to induce macrophage apoptosis. These pathways may be important in immune processes such as macrophage homeostasis as well as in down-regulation of immune responses and elimination of macrophages infected with intracellular organisms.
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Affiliation(s)
- M J Kaplan
- Department of Medicine, University of Michigan, and Veterans Affairs Medical Center, Ann Arbor MI 48109, USA
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Abstract
Our group reported that inhibiting DNA methylation in human T cells increases DNA methyltransferase expression and activity, and suggested that this may represent a response to DNA hypomethylation. The increase correlates with increases in Ha-ras and c-jun, suggesting that increased signaling through the ras-MAPK pathway, due to overexpression of some elements, may be responsible. However, whether human DNA MTase is regulated by the ras-MAPK pathway, and whether overexpression of elements in this pathway will increase DNA MTase, is unknown. We report that treating cells with a DNA methylation inhibitor increases transcription regulated by a putative DNA MTase promoter, and that this increase requires AP-1 sites. Additional studies demonstrate that overexpression of an unmutated Ha-ras causes an increase in DNA MTase, and that human T cell DNA MTase can be decreased by inhibiting signaling through the ras-MAPK pathway. Together, these studies suggest that human T cell DNA MTase is regulated through the ras-MAPK pathway, and that overexpression of Ha-ras is sufficient to increase DNA MTase expression. These results thus provide a mechanism for the increase in DNA MTase observed after inducing DNA hypomethylation, a response which may have relevance to some disease states.
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Affiliation(s)
- C Deng
- Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0940, USA
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Yang J, Deng C, Hemati N, Hanash SM, Richardson BC. Effect of mitogenic stimulation and DNA methylation on human T cell DNA methyltransferase expression and activity. J Immunol 1997; 159:1303-9. [PMID: 9233626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
DNA methylation, a mechanism modifying gene expression, is mediated in part by the enzyme DNA methyltransferase. Reduced levels of T cell DNA methyltransferase have been observed in lupus-like diseases, and increased levels have been reported in malignancies. Little is known concerning the regulation of human DNA methyltransferase. In this report we demonstrate that mitogenic T cell stimulation causes an increase in DNA methyltransferase mRNA and enzyme activity. We also show that pharmacologic inhibition of T cell DNA methylation causes an increase in the rate of DNA methyltransferase mRNA transcription and a corresponding increase in mRNA levels and enzyme activity. This suggests that DNA methyltransferase is itself regulated in part by DNA methylation status, possibly representing a feedback mechanism. DNA methylation inhibition also resulted in an increase in Ha-ras and c-jun mRNA levels, overexpression of which increases DNA methyltransferase in murine systems. These results thus identify two mechanisms regulating levels of human T cell DNA methyltransferase and raise the possibility that abnormalities in either could contribute to disorders associated with altered DNA methylation.
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Affiliation(s)
- J Yang
- Department of Internal Medicine, University of Michigan, Ann Arbor 48109, USA
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