Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have determined that abnormal DNA methylation in T cells coincides with the development of autoimmunity, using a mouse model that exhibits an age-dependent lupus-like disease (MRL/lpr mice). Splenic CD4(+) T cells were isolated from these mice at 5 and 16 wk of age (before and after autoimmunity is established) and the expression of DNA methyltransferase 1 (Dnmt1) and the methylation-sensitive gene Tnfsf7 (CD70) was measured. Bisulfite DNA sequencing was used to monitor the methylation status of the Tnfsf7 gene. We found that Dnmt1 steady-state mRNA levels were significantly lower in 16-wk-old MRL/lpr mice, which had established autoimmunity, compared to the 5-wk-old MRL/lpr mice. Furthermore, the expression of CD70 was higher in MRL/lpr mice at 16 wk. CD70 was overexpressed in MRL/lpr mice compared to age- and sex-matched MRL(+/+) controls. Bisulfite DNA sequencing of the Tnfsf7 gene in MRL/lpr mice revealed that at 16 wk, CG pairs were hypomethylated compared to 5-wk-old mice, and that Tnfsf7 from MRL/lpr mice was hypomethylated at 16 wk relative to age-matched MRL(+/+) controls. Our data indicate that decreased expression of Dnmt1 and the corresponding T cell DNA hypomethylation correlate with the development of age-dependent autoimmunity in MRL/lpr mice.
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PMID:Defective DNA methylation and CD70 overexpression in CD4+ T cells in MRL/lpr lupus-prone mice. 1742 46

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies against a host of nuclear antigens. The pathogenesis of lupus is incompletely understood. Environmental factors may play a role via altering DNA methylation, a mechanism regulating gene expression. In lupus, genes including CD11a and CD70 are overexpressed in T cells as a result of promoter hypomethylation. T-cell DNA methyltransferase expression is regulated in part by the extracellular signal-regulated kinase (ERK) signaling pathway. In this study, we investigate the effects of decreased ERK pathway signaling in T cells using transgenic animals. We generated a transgenic mouse that inducibly expresses a dominant-negative MEK in T cells in the presence of doxycycline. We show that decreased ERK pathway signaling in T cells results in decreased expression of DNA methyltransferase 1 and overexpression of the methylation-sensitive genes CD11a and CD70, similar to T cells in human lupus. Our transgenic animal model also develops anti-dsDNA antibodies. Interestingly, microarray expression assays revealed overexpression of several interferon-regulated genes in the spleen similar to peripheral blood cells of lupus patients. This model supports the contention that ERK pathway signaling defects in T cells contribute to the development of autoimmunity.
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PMID:Defective T-cell ERK signaling induces interferon-regulated gene expression and overexpression of methylation-sensitive genes similar to lupus patients. 1852 34

The pathogenesis of systemic lupus erythematosus (SLE) is incompletely understood. Studies in both lupus animal models and human disease indicate a clear role for epigenetic defects, particularly DNA methylation, in the pathogenesis of lupus. T-cell DNA from active lupus patients is hypomethylated, which results in overexpression of methylation-regulated genes, T-cell autoreactivity, and autoimmunity in vivo. Inducing an extracellular signal-regulated kinase (ERK) signaling defect in T cells using a transgenic mouse model resulted in reduced DNA methyltransferase 1 (DNMT1) expression, overexpression of methylation-sensitive genes, and anti-double-stranded DNA (anti-dsDNA) antibody production. ERK signaling is known to be defective in lupus T cells, and this defect is now explained by impaired T-cell protein kinase C (PKC) delta activation. Herein, we discuss how defective epigenetic regulation is involved in the pathogenesis of lupus, which includes both DNA methylation and histone modification changes.
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PMID:Epigenetic regulation and the pathogenesis of systemic lupus erythematosus. 1913 48

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease, in which sunlight (especially ultraviolet B (UVB) 290-320 nm) is known to induce exacerbation of disease. DNA methylation regulates gene expression, and hypomethylation is associated with abnormal cell function in SLE. The purpose of this study was to investigate the effect of UVB on DNA methylation in SLE and its significance in the pathogenesis of SLE. Forty-five patients with SLE and 20 healthy controls were enrolled in the study, which involved the investigation of DNA methylation and DNA methyltransferase 1 (DNMT1) of peripheral blood mononuclear cells with UVB irradiation. Our results demonstrate the following: The level of DNA methylation in patients with SLE was lower than that in the control group. DNA methylation was decreased after UVB irradiation at different dosages especially in patients with marlar rashes and leucopenia, but no significant difference was observed in the DNMT1 mRNA expression. DNA methylation levels in patients with active SLE were more sensitive to UVB. In conclusion, UVB exposure is able to inhibit DNA methylation, which subsequently takes part in the pathogenesis of SLE.
Lupus 2009 Oct
PMID:Ultraviolet B exposure of peripheral blood mononuclear cells of patients with systemic lupus erythematosus inhibits DNA methylation. 1976 76

T cell DNA methylation levels decline with age, activating genes such as KIR and TNFSF7 (CD70), implicated in lupus-like autoimmunity and acute coronary syndromes. The mechanisms causing age-dependent DNA demethylation are unclear. Maintenance of DNA methylation depends on DNA methyltransferase 1 (Dnmt1) and intracellular S-adenosylmethionine (SAM) levels, and is inhibited by S-adenosylhomocysteine (SAH). SAM levels depend on dietary micronutrients including folate and methionine. SAH levels depend on serum homocysteine concentrations. T cell Dnmt1 levels also decline with age. We hypothesized that age-dependent Dnmt1 decreases synergize with low folate, low methionine or high homocysteine levels to demethylate and activate methylation-sensitive genes. T cells from healthy adults ages 22-81, stimulated and cultured with low folate, low methionine, or high homocysteine concentrations showed demethylation and overexpression of KIR and CD70 beginning at age approximately 50 and increased further with age. The effects were reproduced by Dnmt1 knockdowns in T cells from young subjects. These results indicate that maintenance of T cell DNA methylation patterns is more sensitive to low folate and methionine levels in older than younger individuals, due to low Dnmt1 levels, and that homocysteine further increases aberrant gene expression. Thus, attention to proper nutrition may be particularly important in the elderly.
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PMID:Age-dependent decreases in DNA methyltransferase levels and low transmethylation micronutrient levels synergize to promote overexpression of genes implicated in autoimmunity and acute coronary syndromes. 2003 56

DNA demethylation and histone hyperacetylation of CD11a and CD70 regulatory regions contribute to the development of autoreactivity and autoantibody overstimulation in CD4(+) T cells of patients with systemic lupus erythematosus (SLE). However, the mechanisms causing these changes remain largely unknown. We report that the expression and activity of the transcription factor RFX1 are decreased in SLE CD4(+) T cells. We demonstrate that RFX1 affects DNA methylation and histone acetylation in CD4(+) T cells by recruiting the co-repressors DNMT1 and HDAC1 to the CD11a and CD70 promoters, and thereby represses their expression. Reducing RFX1 in CD4(+) T cells is sufficient to cause lupus-like T and B cell hyperactivity, whereas overexpressing RFX1 suppresses T cell reactivity. These findings reveal a crucial role for RFX1 in regulating the epigenetic status of T cells, and demonstrate that autoimmune responses in SLE are due in part to RFX1 downregulation.
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PMID:Epigenetics and SLE: RFX1 downregulation causes CD11a and CD70 overexpression by altering epigenetic modifications in lupus CD4+ T cells. 2022 37

Systemic lupus erythematosus is a complex autoimmune disease caused by genetic and epigenetic alterations. DNA methylation abnormalities play an important role in systemic lupus erythematosus disease processes. MicroRNAs (miRNAs) have been implicated as fine-tuning regulators controlling diverse biological processes at the level of posttranscriptional repression. Dysregulation of miRNAs has been described in various disease states, including human lupus. Whereas previous studies have shown miRNAs can regulate DNA methylation by targeting the DNA methylation machinery, the role of miRNAs in aberrant CD4+ T cell DNA hypomethylation of lupus is unclear. In this study, by using high-throughput microRNA profiling, we identified that two miRNAs (miR-21 and miR-148a) overexpressed in CD4+ T cells from both patients with lupus and lupus-prone MRL/lpr mice, which promote cell hypomethylation by repressing DNA methyltransferase 1 (DNMT1) expression. This in turn leads to the overexpression of autoimmune-associated methylation-sensitive genes, such as CD70 and LFA-1, via promoter demethylation. Further experiments revealed that miR-21 indirectly downregulated DNMT1 expression by targeting an important autoimmune gene, RASGRP1, which mediated the Ras-MAPK pathway upstream of DNMT1; miR-148a directly downregulated DNMT1 expression by targeting the protein coding region of its transcript. Additionally, inhibition of miR-21 and miR-148a expression in CD4+ T cells from patients with lupus could increase DNMT1 expression and attenuate DNA hypomethylation. Together, our data demonstrated a critical functional link between miRNAs and the aberrant DNA hypomethylation in lupus CD4+ T cells and could help to develop new therapeutic approaches.
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PMID:MicroRNA-21 and microRNA-148a contribute to DNA hypomethylation in lupus CD4+ T cells by directly and indirectly targeting DNA methyltransferase 1. 2048 47

In recent years, compelling evidence has been gathered that supports a role for epigenetic alterations in the pathogenesis of systemic lupus erythematosus (SLE). Different blood cell populations of SLE patients are characterized by a global loss of DNA methylation. This process is associated with defects in ERK pathway signalling and consequent DNMT 1 downregulation. Hypomethylation of gene promoters has been described, which permits transcriptional activation and therefore functional changes in the cells and also hypomethylation of the ribosomal RNA gene cluster. Among the identified targets undergoing demethylation are genes involved in autoreactivity (ITGAL), osmotic lysis and apoptosis (PRF1, MMP14 and LCN2), antigen presentation (CSF3R), inflammation(MMP 14), B- T-cell interaction (CD70 and CD40LG) and cytokine pathways (CSF3R, IL-4, IL-6 and IFNGR2). DNA methylation inhibitors are also known to induce autoreactivity in vitro and cause a lupus-like disease in vivo. Further, altered patterns of histone modifications have been described in SLE. CD4+ lymphocytes undergo global histone H3 and H4 deacetylation and consequent skewed gene expression. Although multiple lines of evidence highlight the contribution of epigenetic alterations to the pathogenesis of lupus in genetically predisposed individuals, many questions remain to be answered. Attaining a deeper understanding of these matters will create opportunities in the promising area of epigenetic treatments.
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PMID:A new epigenetic challenge: systemic lupus erythematosus. 2162 46

The focus of the present review is on the extent to which epigenetic alterations influence the development of systemic lupus erythematosus. Lupus is a systemic autoimmune disease characterized by the production of autoantibodies directed at nuclear self-antigens. A DNA methylation defect in CD4+ T cells has long been observed in idiopathic and drug-induced lupus. Recent studies utilizing high-throughput technologies have further characterized the nature of the DNA methylation defect in lupus CD4+ T cells. Emerging evidence in the literature is revealing an increasingly interconnected network of epigenetic dysregulation in lupus. Recent reports describe variable expression of a number of regulatory microRNAs in lupus CD4+ T cells, some of which govern the expression of DNA methyltransferase 1. While studies to date have revealed a significant role for epigenetic defects in the pathogenesis of lupus, the causal nature of epigenetic variation in lupus remains elusive. Future longitudinal epigenetic studies in lupus are therefore needed.
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PMID:The role of epigenetic variation in the pathogenesis of systemic lupus erythematosus. 2204 22

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder of an unclearly determined etiology. Past studies, both epidemiological and biological, have implicated epigenetic influences in disease etiology and pathogenesis. Epigenetics describes changes in gene expression not linked to alterations in the underlying genomic sequence, and is most often typified by three modifications: methylation of DNA, addition of various side chains to histone groups and transcriptional regulation via short ncRNA sequences. The purpose of this article is to review the most important advances that link epigenetic changes to lupus. The contribution of DNA methylation changes to lupus pathogenesis is discussed. These include the role of apoptotic DNA, ultraviolet radiation, endogenous retroviruses, dietary contributions and aging. Hypomethylation of specific genes overexpressed in lupus T cells such as ITGAL (CD11a), CD40LG (CD40L), TNFSF7 (CD70), KIR2DL4 and PRF1 (perforin), and CD5 in lupus B cells seem to play an important role. Moreover, histone modifications such as increased global H4 acetylation in monocytes are highly associated with SLE. NcRNAs, especially miR-21, miR-148a and miR-126, control other elements of epigenetic regulation; particularly, transcription of the maintenance DNA methylation enzyme DNMT1. Epigenetic contributions to SLE etiology have been well established, but much is still unknown. Epigenome-wide studies coupled with functional analysis of the epigenomic changes discovered will uncover novel pathways important in disease pathogenesis. Epigenetic therapies for SLE may be feasible in the future, particularly if they are designed to target specific regions within the genome.
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PMID:Epigenetics in systemic lupus erythematosus: leading the way for specific therapeutic agents. 2218 3


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