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Interferon Regulatory Factor (interferon + regulatory_factor)

Distribution by Scientific Domains

Medical Sciences	75%
Life Sciences	12%

Selected Abstracts

Interferon regulatory factor-1 acts as a powerful adjuvant in tat DNA based vaccination,

JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2010
Arianna Castaldello
Genetic vaccines are safe cost-effective approaches to immunization but DNA immunization is an inefficient process. There is, therefore, a pressing need for adjuvants capable of enhancing the immunogenicity and effectiveness of these vaccines. This is particularly important for diseases for which successful vaccines are still lacking, such as cancer and infectious diseases including HIV-1/AIDS. Here we report an approach to enhance the immunogenicity of DNA vaccines involving the use of transcription factors of the Interferon regulatory factor (IRF) family, specifically IRF-1, IRF-3, and IRF-7 using the tat gene as model antigen. Balb/c mice were immunized by three intramuscular inoculations, using a DNA prime-protein boost protocol, with a DNA encoding tat of HIV-1 and the indicated IRFs and immune responses were compared to those induced by vaccination with tat DNA alone. In vivo administration of plasmid DNA encoding IRF-1, or a mutated version of IRF-1 deleted of the DNA-binding domain, enhanced Tat-specific immune responses and shifted them towards a predominant T helper 1-type immune response with increased IFN-, production and cytotoxic T lymphocytes responses. Conversely, the use of IRF-3 or IRF-7 did not affect the tat -induced responses. These findings define IRF-1 and its mutated form as efficacious T helper 1-inducing adjuvants in the context of tat- based vaccination and also providing a new promising candidate for genetic vaccine development. J. Cell. Physiol. 224: 702,709, 2010. © 2010 Wiley-Liss, Inc. [source]

Lack of association between IRF6 polymorphisms (rs2235371 and rs642961) and non-syndromic cleft lip and/or palate in a Brazilian population

ORAL DISEASES, Issue 2 2010
LMR Paranaíba
Oral Diseases (2010) 16, 193,197 Background:, Interferon regulatory factor 6 (IRF6) gene has emerged as a potential susceptibility gene for non-syndromic cleft lip and/or palate (NSCL/P) in different populations. The aim of this study was to determine the association of IRF6 rs2235371 and rs642961 polymorphisms with NSCL/P in a Brazilian population. Methods:, Two hundred and twenty-eight patients affected by NSCL/P and 126 healthy individuals were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Results:, Overall genotype distributions of rs2235371 and rs642961 polymorphisms were as expected by Hardy-Weinberg equilibrium test. The rs2235371 polymorphic genotype GA was identified in 10.1% of the patients with NSCL/P and in 10.3% of the control group, revealing no statistical difference. Similarly, the frequency of rs642961 minor genotypes (GA and AA) was quite similar between control group (28.6%) and NSCL/P group (25.4%), without significant difference. Conclusion:, Our findings are consistent with a lack of involvement of IRF6 rs2235371 and rs642961 polymorphisms in the NSCL/P pathogenesis in the Brazilian population. [source]

The CGGGG insertion/deletion polymorphism of the IRF5 promoter is a strong risk factor for primary Sjögren's syndrome

ARTHRITIS & RHEUMATISM, Issue 7 2009
Corinne Miceli-Richard
Objective Interferon regulatory factor 5 is a transcription factor involved in type I interferon (IFN) secretion. This study was undertaken to investigate whether a 5-bp (CGGGG insertion/deletion) promoter polymorphism is involved in genetic predisposition to primary Sjögren's syndrome (SS) and to assess the functional consequences of this polymorphism. Methods The exploratory cohort consisted of 185 patients with primary SS and 157 healthy controls, and the replication cohort consisted of 200 patients with primary SS and 282 healthy controls. Levels of IRF5 messenger RNA (mRNA) were assessed at baseline and after in vitro infection with reovirus in peripheral blood mononuclear cells (PBMCs) from 30 patients with primary SS and from salivary gland epithelial cells that had been cultured for 4 weeks from patients with primary SS or sicca symptoms. Results Carriage of the IRF5 4R CGGGG allele was associated with a greatly increased risk of primary SS in both cohorts (odds ratio 2.00 [95% confidence interval 1.5,2.7], P = 6.6 × 10,6). The CGGGG insertion/deletion polymorphism alone was sufficient to explain the association of primary SS with IRF5. The level of IRF5 mRNA in PBMCs depended significantly on genotype (P = 0.002) and was correlated with the levels of mRNA for the IFN-induced genes MX1 and IFITM1. Cultured salivary gland epithelial cells from patients carrying the 4R CGGGG IRF5 allele showed a high level of IRF5 mRNA (P = 0.04), which was amplified after reovirus infection (P = 0.026). Conclusion Our findings indicate an association of the CGGGG insertion/deletion polymorphism of the IRF5 promoter with primary SS. Patients carrying the 4R CGGGG IRF5 allele had a high level of mRNA for IRF5 in PBMCs and salivary gland epithelial cells, mainly after in vitro viral infection. Patients with high levels of mRNA for IRF5 also had high levels of mRNA for type I IFN,induced genes in PBMCs. [source]

Association of a functional polymorphism in the IRF5 region with systemic sclerosis in a Japanese population

ARTHRITIS & RHEUMATISM, Issue 6 2009
Ikue Ito
Objective Interferon regulatory factor 5, an established susceptibility factor for systemic lupus erythematosus (SLE), plays a role in type I interferon and proinflammatory cytokine induction. A recent study showed association of a functional single-nucleotide polymorphism (SNP) in intron 1 of IRF5, rs2004640, with systemic sclerosis (SSc) in a European French population. We undertook the present study to determine whether IRF5 polymorphisms are also associated with a predisposition to SSc in Japanese. Methods A case,control association study was performed for rs2004640 as well as for rs10954213 and rs2280714, all of which were previously reported to be associated with SLE, in 281 SSc patients and 477 healthy controls. Patients with SSc complicated by SLE or Sjögren's syndrome were excluded. Association of the rs2280714 genotype with messenger RNA (mRNA) levels of IRF5 and adjacently located transportin 3 (TNPO3) was examined using the GENEVAR database. Results All 3 SNPs were significantly associated with SSc, with the rs2280714 A allele having the strongest association (allele frequency P = 0.0012, odds ratio 1.42 [95% confidence interval 1.15,1.75]). Association was preferentially observed in subsets of patients with diffuse cutaneous SSc (dcSSc) and anti,topoisomerase I antibody positivity. Conditional analysis revealed that rs2280714 could account for most of the association of these SNPs, while an additional contribution of rs2004640 was also suggested for dcSSc. The genotype of rs2280714 was strongly associated with IRF5 mRNA expression, while only marginal association was detected with TNPO3 mRNA expression. Conclusion Association of IRF5 with SSc was replicated in a Japanese population. Whether the causal SNP is different among populations requires further investigation. [source]

Mutation screening of interferon regulatory factor 1 gene (IRF-1) as a candidate gene for atopy/asthma

CLINICAL & EXPERIMENTAL ALLERGY, Issue 11 2000
E. Noguchi
Background IL-4 gene cluster on chromosome 5 contains several candidate genes for atopy and asthma. Several independent studies have shown evidence for linkage between the markers flanking IL-4 gene cluster and asthma and/or asthma-related traits. Interferon regulatory factor 1 (IRF-1) is located approximately 300 kb telomeric to IL-4 and recent study reveals that IRF-1 deficiency results in an elevated production of Th2-related cytokines and a compensatory decrease in the expression of native cell- and Th1-related cytokines. Objective To determine if there are any mutations associated with the development of atopy and asthma present in the coding exons and 5, flanking region of the IRF-1 gene. Methods and results We have screened the promoter and coding regions of the IRF-1 gene in atopic asthmatics and controls by SSCP method. We found three novel nuclear variants (the ,300G/T and 4396 A/G polymorphisms and the 6355G > A rare variant) in the IRF-1 gene. No variants causing amino acid alterations of IRF-1 were detected. The ,300G/T polymorphism was in nearly complete linkage disequilibrium with the 4396 A/G polymorphism. An association between the 4396 A > G polymorphism and atopy/asthma was examined by transmission disequilibrium test in 81 asthmatic families. Either of 4396 A or 4396G alleles was not significantly preferentially transmitted to atopy- or asthma-affected children. Conclusion The IRF-1 gene is less likely to play a substantial role in the development of atopy and asthma in the Japanese population. [source]

Association between the IRF5 rs2004640 functional polymorphism and systemic sclerosis: A new perspective for pulmonary fibrosis

ARTHRITIS & RHEUMATISM, Issue 1 2009
P. Dieudé
Objective There is now growing evidence that connective tissue diseases, including systemic sclerosis (SSc), share a common genetic background. Microarray studies support a pivotal role of type I interferon (IFN) in the pathophysiology of connective tissue diseases. Interferon regulatory factors coordinate the expression of type I IFNs, and the IRF5 gene has been identified as a susceptibility gene of systemic lupus and Sjögren's syndrome. The aim of this study was to determine whether the IRF5 rs2004640 single-nucleotide polymorphism is associated with SSc. Methods The IRF5 rs2004640 (GT) functional polymorphism was genotyped in 1,641 subjects of French European Caucasian origin: a discovery set comprising 427 patients with SSc and 380 control subjects and a replication set comprising 454 patients with SSc and 380 control subjects. Results In both the discovery set and the replication set, the TT genotype was significantly more common in patients with SSc than in control subjects, with an odds ratio (OR) for the combined populations of 1.58 (95% confidence interval [95% CI] 1.18,2.11 [P for trend 0.002]). Analyses of the whole SSc population showed a significant association between homozygosity for the T allele and the presence of antinuclear antibodies (corrected P [Pcorr] = 0.04, OR 1.59, 95% CI 1.16,2.17) and fibrosing alveolitis (Pcorr = 0.001, OR 2.07, 95% CI 1.38,3.11). In a multivariate analysis model including the diffuse cutaneous subtype of SSc and positivity for anti,topoisomerase I antibodies, the IRF5 rs2004640 TT genotype remained associated with fibrosing alveolitis (P = 0.029, OR 1.92, 95% CI 1.07,3.44). Conclusion The IRF5 rs2004640 GT substitution is associated with susceptibility to SSc. These data provide new insight into the pathogenesis of SSc, including clues to the mechanisms leading to fibrosing alveolitis. [source]

DNA methylation of interferon regulatory factors in gastric cancer and noncancerous gastric mucosae

CANCER SCIENCE, Issue 7 2010
Masaki Yamashita
Interferon regulatory factors (IRFs) are transcription factors known to play key roles in innate and adaptive immune responses, cell growth, apoptosis, and development. Their function in tumorigenesis of gastric cancer remains to be determined, however. In the present study, therefore, we examined epigenetic inactivation of IRF1,9 in a panel of gastric cancer cell lines. We found that expression of IRF4, IRF5, and IRF8 was frequently suppressed in gastric cancer cell lines; that methylation of the three genes correlated with their silencing; and that treating the cells with the demethylating agent 5-aza-2,-deoxycytidine (DAC) restored their expression. Expression of IRF5 in cancer cells was enhanced by the combination of DAC treatment and adenoviral vector-mediated expression of p53, p63, or p73. Interferon-,-induced expression of IRF8 was also enhanced by DAC. Moreover, treating gastric cancer cells with DAC enhanced the suppressive effects of interferon-,, interferon-,, and interferon-, on cell growth. Among a cohort of 455 gastric cancer and noncancerous gastric tissue samples, methylation of IRF4 was frequently observed in both gastric cancer specimens and noncancerous specimens of gastric mucosa from patients with multiple gastric cancers, which suggests IRF4 methylation could be a useful molecular marker for diagnosing recurrence of gastric cancers. Our findings indicate that epigenetic IRF inactivation plays a key role in tumorigenesis of gastric cancer, and that inhibition of DNA methylation may restore the antitumor activity of interferons through up-regulation of IRFs. (Cancer Sci 2010) [source]

Mechanism for transcriptional synergy between interferon regulatory factor (IRF)-3 and IRF-7 in activation of the interferon-, gene promoter

FEBS JOURNAL, Issue 18 2004
Hongmei Yang
The interferon-, promoter has been studied extensively as a model system for combinatorial transcriptional regulation. In virus-infected cells the transcription factors ATF-2, c-Jun, interferon regulatory factor (IRF)-3, IRF-7 and NF-,B, and the coactivators p300/CBP play critical roles in the activation of this and other promoters. It remains unclear, however, why most other combinations of AP-1, IRF and Rel proteins fail to activate the interferon-, gene. Here we have explored how different IRFs may cooperate with other factors to activate transcription. First we showed in undifferentiated embryonic carcinoma cells that ectopic expression of either IRF-3 or IRF-7, but not IRF-1, was sufficient to allow virus-dependent activation of the interferon-, promoter. Moreover, the activity of IRF-3 and IRF-7 was strongly affected by promoter context, with IRF-7 preferentially being recruited to the natural interferon-, promoter. We fully reconstituted activation of this promoter in insect cells. Maximal synergy required IRF-3 and IRF-7 but not IRF-1, and was strongly dependent on the presence of p300/CBP, even when these coactivators only modestly affected the activity of each factor by itself. These results suggest that specificity in activation of the interferon-, gene depends on a unique promoter context and on the role played by coactivators as architectural factors. [source]

Transcriptional activity of interferon regulatory factor (IRF)-3 depends on multiple protein,protein interactions

FEBS JOURNAL, Issue 24 2002
Hongmei Yang
Virus infection results in the activation of a set of cellular genes involved in host antiviral defense. IRF-3 has been identified as a critical transcription factor in this process. The activation mechanism of IRF-3 is not fully elucidated, yet it involves a conformational change triggered by the virus-dependent phosphorylation of its C-terminus. This conformational change leads to nuclear accumulation, DNA binding and transcriptional transactivation. Here we show that two distinct sets of Ser/Thr residues of IRF-3, on phosphorylation, synergize functionally to achieve maximal activation. Remarkably, we find that activated IRF-3 lacks transcriptional activity, but activates transcription entirely through the recruitment of the p300/CBP coactivators. Moreover, we show that two separate domains of IRF-3 interact with several distinct regions of p300/CBP. Interference with any of these interactions leads to a complete loss of transcriptional activity, suggesting that a bivalent interaction is essential for coactivator recruitment by IRF-3. [source]

Genetic variants in IRF6 and the risk of facial clefts: single-marker and haplotype-based analyses in a population-based case-control study of facial clefts in Norway

GENETIC EPIDEMIOLOGY, Issue 5 2008
Astanand Jugessur
Abstract Mutations in the gene encoding interferon regulatory factor 6 (IRF6) underlie a common form of syndromic clefting known as Van der Woude syndrome. Lip pits and missing teeth are the only additional features distinguishing the syndrome from isolated clefts. Van der Woude syndrome, therefore, provides an excellent model for studying the isolated forms of clefting. From a population-based case-control study of facial clefts in Norway (1996,2001), we selected 377 cleft lip with or without cleft palate (CL/P), 196 cleft palate only (CPO), and 763 control infant-parent triads for analysis. We genotyped six single nucleotide polymorphisms within the IRF6 locus and estimated the relative risks (RR) conferred on the child by alleles and haplotypes of the child and of the mother. On the whole, there were strong statistical associations with CL/P but not CPO in our data. In single-marker analyses, mothers with a double-dose of the ,a'-allele at rs4844880 had an increased risk of having a child with CL/P (RR=1.85, 95% confidence interval: 1.04,3.25; P=0.036). An RR of 0.38 (95% confidence interval: 0.16,0.92; P=0.031) was obtained when the child carried a single-dose of the ,a'-allele at rs2235371 (the p.V274I polymorphism). The P -value for the overall test was <0.001. In haplotype analyses, several of the fetal and maternal haplotype relative risks were statistically significant individually but were not strong enough to show up on the overall test (P=0.113). Taken together, these findings further support a role for IRF6 variants in clefting of the lip and provide specific risk estimates in a Norwegian population. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source]

The TLR3 ligand polyI:C downregulates connexin 43 expression and function in astrocytes by a mechanism involving the NF-,B and PI3 kinase pathways

GLIA, Issue 8 2006
Yongmei Zhao
Abstract Toll-like receptor 3 (TLR3) is a component of the innate immune response that responds to dsRNA viruses and virus replication intermediates. In this study we show that activation of astrocytes with the dsRNA mimetic polyinosinic-cytidylic acid (pI:C) results in loss of expression of connexin43 (Cx43) mRNA and protein while upregulating the expression of the ionotropic P2 receptor P2X4R. Analysis of the signaling pathways involved failed to demonstrate a role for the p38 MAP kinase, ERK, or JNK signaling pathways whereas an inhibitor of the PI3 kinase/Akt pathway effectively blocked the action of pI:C. Using adenoviral vectors containing a super-repressor of NF-,B (NF-,B SR) construct or a dominant negative interferon regulatory factor 3 (dnIRF3) construct showed that inhibition of both transcription factors also blocked the effects of pI:C. To explore the functional consequences of pI:C activation we used a pore-forming assay for P2X4R activity and a scrape loading assay for gap junction intercellular communication (GJIC). No pore-forming activity consistent with functional P2X4R expression was detected in either control or activated astrocytes. In contrast, robust Lucifer yellow transfer indicative of GJIC was detected in resting cells that was lost following pI:C activation. The dnIRF3 construct failed to restore GJIC whereas the NF-,B SR or the NF-,B inhibitor BAY11-7082 and the PI3K inhibitor LY294002 all significantly reversed the effect of pI:C on GJ connectivity. We conclude that activation of the innate immune response in astrocytes is associated with functional loss of GJIC through a pathway involving NF-,B and PI3 kinase. © 2006 Wiley-Liss, Inc. [source]

Hepatitis C virus escape from the interferon regulatory factor 3 pathway by a passive and active evasion strategy,

HEPATOLOGY, Issue 5 2007
Marco Binder
Hepatitis C virus (HCV) has been known to replicate with extremely varying efficiencies in different host cells, even within different populations of a single human hepatoma cell line, termed Huh-7. Several reports have implicated the retinoic-acid inducible gene I (RIG-I)/ interferon regulatory factor 3 (IRF-3) pathway of the innate antiviral response with differences in host cell permissiveness to HCV. To investigate the general impact of the IRF-3 response onto HCV replication in cell culture, we generated an ample array of stable Huh-7 cell lines with altered IRF-3 responsiveness. Neither blocking IRF-3 activation in various host cells by expression of dominant negative RIG-I or HCV NS3/4A protease nor reconstitution of RIG-I signaling in Huh7.5, a cell clone known to be defective in this pathway, had any impact on HCV replication. Only by overexpressing constitutively active RIG-I or the signaling adaptor Cardif (also known as interferon-beta promoter stimulator 1, mitochondrial anti-viral signaling protein, or virus-induced signaling adaptor), both leading to a stimulation of the IRF-3 pathway in the absence of inducers, was HCV replication significantly inhibited. We therefore assessed the extent of RIG-I, dependent IRF-3 activation by different species of RNA, including full-length HCV genomes and HCV RNA duplexes, and observed strong induction only in response to double-stranded RNAs. Conclusion: Based on these findings, we propose a refined model of innate immune escape by HCV involving limited initial induction and stringent subsequent control of the IRF-3 response. (HEPATOLOGY 2007.) [source]

Expression of interferon-, subtypes in peripheral mononuclear cells from patients with chronic hepatitis C: a role for interferon-,5

JOURNAL OF VIRAL HEPATITIS, Issue 2 2001
E. Larrea
Interferon (IFN)-, is a family of antiviral proteins encoded by different genes. The biological significance of the existence of various IFN-, subtypes is not clear. We have investigated the interferon system in chronic hepatitis C virus (HCV) infection, a disease that responds to interferon-,2 therapy in only a limited proportion of cases. We analysed the expression of interferon regulatory factor (IRF)-1, IRF-2, and IFN-, subtypes in nonstimulated and Sendai virus-stimulated peripheral blood mononuclear cells (PBMC) from HCV infected patients and healthy controls. We observed that the IRF-1 mRNA and IRF-1/IRF-2 ratios were increased in PBMC from hepatitis C patients with respect to normal subjects. Sendai virus stimulation of PBMC led to a significant increase in the levels of IRF-1, IRF-2 and IFN-, mRNAs and in the production of IFN-, protein with respect to basal values in healthy controls as well as in patients with HCV infection. In addition, we found that while natural HCV infection induced increased IFN-,5 expression in PBMC, in vitro infection of these cells with Sendai virus caused a raise in the expression of IFN-,8 in both patients and normal controls. In summary, our results indicate that virus-induced activation of the IFN system in human PBMC is associated with selective expression of individual IFN-, subtypes, IFN-,5 being the specific subtype induced in PBMC from patients with chronic HCV infection. [source]

Gene expression profiling of acute cellular rejection in rat liver transplantation using DNA microarrays

LIVER TRANSPLANTATION, Issue 5 2009
Naoki Hama
Acute cellular rejection (ACR) is still a major problem in organ transplantation, and its genetic and molecular mechanisms remain poorly understood. We used DNA microarrays to investigate the gene expression profiles in ACR. We hypothesized that changes of gene expression in grafts could also be detected in peripheral blood leukocytes. We first compared the gene expression profiles in liver isografts (Lewis to Lewis) and allografts (Dark Agouti to Lewis) harvested from rats at days 1, 3, 5, and 7 after transplantation. Hierarchical clustering analysis indicated that gene expression started to change on day 3, and 89 differentially expressed genes were extracted from allografts in comparison with isografts at day 3. Most of the up-regulated genes were associated with graft-infiltrating leukocytes. We then confirmed the similarity of gene expression changes in peripheral leukocytes by quantitative real-time polymerase chain reaction. We also investigated the gene expression changes in other inflammatory and liver dysfunction models. Two interferon-gamma inducible genes, interferon regulatory factor 1 and guanylate nucleotide binding protein 2, were overexpressed in both the peripheral leukocytes and liver graft during ACR. Although further studies are necessary, these 2 genes in peripheral leukocytes could be potentially useful markers for rejection or immunosuppression. Liver Transpl 15:509,521, 2009. © 2009 AASLD. [source]

Role of mitogen-activated protein kinases, nuclear factor-,B, and interferon regulatory factor 3 in Toll-like receptor 4-mediated activation of HIV long terminal repeat

APMIS, Issue 2 2009
RANDI S. BERG
Monocytes/macrophages are known to represent a potential reservoir of human immunodeficiency virus type 1 (HIV-1), which ensures continuous replication of the virus in patients on highly active antiretroviral therapy (HAART). Infected macrophages are a highly productive source of HIV-1 during infections with common opportunistic pathogens. Previous studies report that toll like receptors (TLR)s play a role in HIV-1 replication in macrophages. Here, we investigate the three main pathways activated through TLR4 and the interactions with the HIV-1 long terminal repeat (LTR), using human embryonic kidney (HEK) 293 cells expressing TLR4 and transfected with a luciferase reporter under the control of the HIV-1 LTR. Here, we demonstrate, that TLR4-mediated activation of HIV-LTR is largely governed by the nuclear factor-,B pathway. Neither of the mitogen-activated protein kinases ERK1/2, JNK, or p38 nor the transcription factor interferon regulatory factor 3 were involved in the direct transactivation of HIV-LTR through stimulation of TLR4. [source]

Genetic variants and disease-associated factors contribute to enhanced interferon regulatory factor 5 expression in blood cells of patients with systemic lupus erythematosus

ARTHRITIS & RHEUMATISM, Issue 2 2010
Di Feng
Objective Genetic variants of the interferon (IFN) regulatory factor 5 gene (IRF5) are associated with susceptibility to systemic lupus erythematosus (SLE). The contribution of these variants to IRF-5 expression in primary blood cells of SLE patients has not been addressed, nor has the role of type I IFNs. The aim of this study was to determine the association between increased IRF-5 expression and the IRF5 risk haplotype in SLE patients. Methods IRF-5 transcript and protein levels in 44 Swedish patients with SLE and 16 healthy controls were measured by quantitative real-time polymerase chain reaction, minigene assay, and flow cytometry. Single-nucleotide polymorphisms rs2004640, rs10954213, and rs10488631 and the CGGGG insertion/deletion were genotyped in these patients. Genotypes of these polymorphisms defined both a common risk haplotype and a common protective haplotype. Results IRF-5 expression and alternative splicing were significantly up-regulated in SLE patients compared with healthy donors. Enhanced transcript and protein levels were associated with the risk haplotype of IRF5; rs10488631 displayed the only significant independent association that correlated with increased transcription from the noncoding first exon 1C. Minigene experiments demonstrated an important role for rs2004640 and the CGGGG insertion/deletion, along with type I IFNs, in regulating IRF5 expression. Conclusion This study provides the first formal proof that IRF-5 expression and alternative splicing are significantly up-regulated in primary blood cells of patients with SLE. Furthermore, the risk haplotype is associated with enhanced IRF-5 transcript and protein expression in patients with SLE. [source]

Association of interferon regulatory factor 5 haplotypes, similar to that found in systemic lupus erythematosus, in a large subgroup of patients with rheumatoid arthritis

ARTHRITIS & RHEUMATISM, Issue 5 2008
Rebeca Dieguez-Gonzalez
Objective Previous studies have shown either a lack of effect of IRF5 polymorphisms or an association of the IRF5 gene in only a minor subset of rheumatoid arthritis (RA) patients in whom anti,citrullinated protein antibodies (ACPAs) are absent. The present study was undertaken to investigate the role of genetic variation in IRF5 in susceptibility to RA. Methods Nine IRF5 single-nucleotide polymorphisms (SNPs) were studied in 1,338 patients with RA and 1,342 control subjects in analyses of exploratory and replication sample collections, with stratification according to sex and by the presence or absence of ACPAs, rheumatoid factor, the shared epitope, the 620W PTPN22 allele, and erosions. A meta-analysis that included results from previous studies was also carried out. Results Our findings together with those from previous studies, in a total of 4,620 RA patients and 3,741 controls, showed a significant association of the rs2004640 IRF5 SNP in RA patients as a whole (odds ratio [OR] 0.88, 95% confidence interval [95% CI] 0.83,0.94; P = 6.5 × 10,5 versus controls). This association was stronger in ACPA, patients, but was also present in ACPA+ patients (from 3 sample collections). Further analysis of our exploratory sample collection showed that only patients in the ACPA+ and SE, group lacked an association with IRF5 SNPs. All of the remaining RA patients (ACPA, or SE+) showed a strong association with IRF5 SNPs, which followed a complex pattern of opposing effects mediated by independent haplotypes. The susceptibility haplotype showed an OR of 1.8 (95% CI 1.4,2.3; P = 1.2 × 10,6 versus controls), whereas the protective haplotype showed an OR of 0.76 (95% CI 0.6,0.98; P = 0.046 versus controls). Conclusion IRF5 polymorphisms seem to influence RA susceptibility in a large subgroup of patients, following a pattern of association very similar to that described in patients with systemic lupus erythematosus. [source]

Antiviral gene expression in rheumatoid arthritis: Role of IKK, and interferon regulatory factor 3

ARTHRITIS & RHEUMATISM, Issue 3 2007
Susan E. Sweeney
Objective The rheumatoid synovium displays characteristics of Toll-like receptor (TLR) activation and antiviral gene expression, including production of RANTES and interferon-, (IFN,). The mechanism of this activation in rheumatoid synovial tissue is unknown. This study was designed to investigate the role of the IKK-related kinase IKK, and IFN regulatory factor 3 (IRF-3) in the activation of antiviral genes in rheumatoid arthritis (RA). Methods Kinase assay and immunostaining were performed on synovial tissue. Dominant-negative (DN) IKK, adenoviral infection of human fibroblast-like synoviocytes (FLS) was followed by poly(I-C) stimulation and Western blotting. Quantitative polymerase chain reaction was performed on DN IKK,,infected FLS and IKK,,/, and IKK,+/+ mouse FLS. Results Western blotting showed that IKK, phosphorylation was significantly greater in RA synovium compared with osteoarthritis synovium. Kinase assay confirmed that IKK, was activated in RA synovium, and immunostaining showed localization of pIKK, to the intimal lining. Western blot analysis demonstrated that activation of IRF-3 was also increased in RA synovium. Poly(I-C), lipopolysaccharide, and tumor necrosis factor , (TNF,) activated phosphorylation of IKK, and IRF-3 in FLS. DN IKK, inhibited IRF-3 phosphorylation as well as RANTES and IFN, protein production in synoviocytes. Antiviral gene expression was also reduced in FLS from IKK,,/, mice compared with IKK,+/+ mice. Conclusion Antiviral gene expression in RA, especially due to TLR ligands and TNF,, is dependent on IKK, and IRF-3, and this pathway plays a key role in the production of type I IFNs and chemokines such as RANTES. These findings indicate that the IKK, pathway may have potential as a therapeutic target in RA. [source]

Mutation screening of interferon regulatory factor 1 gene (IRF-1) as a candidate gene for atopy/asthma

Nucleic acid sensing receptors in systemic lupus erythematosus: development of novel DNA- and/or RNA-like analogues for treating lupus

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2010
P. Lenert
Summary Double-stranded (ds) DNA, DNA- or RNA-associated nucleoproteins are the primary autoimmune targets in SLE, yet their relative inability to trigger similar autoimmune responses in experimental animals has fascinated scientists for decades. While many cellular proteins bind non-specifically negatively charged nucleic acids, it was discovered only recently that several intracellular proteins are involved directly in innate recognition of exogenous DNA or RNA, or cytosol-residing DNA or RNA viruses. Thus, endosomal Toll-like receptors (TLR) mediate responses to double-stranded RNA (TLR-3), single-stranded RNA (TLR-7/8) or unmethylated bacterial cytosine (phosphodiester) guanine (CpG)-DNA (TLR-9), while DNA-dependent activator of IRFs/Z-DNA binding protein 1 (DAI/ZBP1), haematopoietic IFN-inducible nuclear protein-200 (p202), absent in melanoma 2 (AIM2), RNA polymerase III, retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) mediate responses to cytosolic dsDNA or dsRNA, respectively. TLR-induced responses are more robust than those induced by cytosolic DNA- or RNA- sensors, the later usually being limited to interferon regulatory factor 3 (IRF3)-dependent type I interferon (IFN) induction and nuclear factor (NF)-,B activation. Interestingly, AIM2 is not capable of inducing type I IFN, but rather plays a role in caspase I activation. DNA- or RNA-like synthetic inhibitory oligonucleotides (INH-ODN) have been developed that antagonize TLR-7- and/or TLR-9-induced activation in autoimmune B cells and in type I IFN-producing dendritic cells at low nanomolar concentrations. It is not known whether these INH-ODNs have any agonistic or antagonistic effects on cytosolic DNA or RNA sensors. While this remains to be determined in the future, in vivo studies have already shown their potential for preventing spontaneous lupus in various animal models of lupus. Several groups are exploring the possibility of translating these INH-ODNs into human therapeutics for treating SLE and bacterial DNA-induced sepsis. [source]