Interferon Regulatory Factor-1 Gene Research Articles

Expression profile of carp IFN correlate with the up-regulation of interferon regulatory factor-1 (IRF-1) in vivo and in vitro: the pivotal molecules in antiviral defense.

Interferon regulatory factors (IRFs) are a family of transcription factors that mediate the transcriptional regulation of interferon (IFN) genes and IFN-inducible genes. In this study, IRF-1 gene is cloned from the common carp, Cyprinus carpio L., named CcIRF-1. The full-length cDNA of CcIRF-1 is 1427 bp, including an open reading frame of 861 bp encoding a protein of 286 amino acids. The putative CcIRF-1 is characterized by a conserved DNA-binding domain and includes a signature of six conserved tryptophan residues. The genomic sequence of CcIRF-1 is described, which consists of 9 exons and 8 introns. The sequence analysis shows that CcIRF-1 is clustered into IRF-1 subfamily, and has the closest relationship with the zebrafish IRF-1. CcIRF-1 is found constitutively expressed in different organs of healthy common carp. The main findings are that CcIRF-1 is up-regulated following stimulation with poly(I:C) in all tested tissues. Moreover, the downstream gene of IRF-1 - IFN is found to be correlated with the up-regulation of IRF-1 after injection with poly(I:C). Furthermore, we also isolate the peripheral blood leukocytes (PBLs) and find that there is a relevance between the expression profile of CcIRF-1 and IFN in poly(I:C) stimulated PBLs.

Positive Darwinian selection within interferon regulatory factor genes of Gymnocypris przewalskii (Cyprinidae) on the Tibetan Plateau.

Tibetan Plateau (TP) had experienced phased uplift, resulting in inhospitable environment of low temperature, hypoxia and high ultraviolet radiation for Tibetan wildlife. Many organisms can well adapt to TP, it is of ecological and evolutionary interest to untangle how organisms adapt to extreme environment on TP through evolution. Previous studies mainly focused on hypoxia and metabolism related genes, but we know little about the evolutionary history of immune genes in Tibetan wildlife. In this study, we first identified 10 interferon regulatory factor (IRF) genes from Tibetan naked carp Gymnocypris przewalskii. Within this gene family, IRF3, IRF5, IRF7 and IRF8 contained positive selection sites. Evidences indicated that positive selection may lead to IRF genes functional alternations, presumably driving genes towards adaptation to the environmental changes. Taken together, our results suggested 4 candidate genes as interesting targets for further experimental confirmation of their functional variations and contributions to high altitude adaptation in Tibet fish.

Cloning and characterizing of the murine IRF-3 gene promoter region.

The interferon regulatory factor 3 (IRF-3) plays essential roles in inflammation and immune response. Here, we cloned the nucleotide sequence of the 5'-flanking region of the murine IRF-3 gene (mIRF-3) and characterized the molecular mechanisms controlling the mIRF-3 transcriptional activity in NIH3T3 cells. Analyses of a series of 5' deletion constructs demonstrated that a 301bp region (-255/+46) of the mIRF-3 gene is sufficient for full promoter activity. This region contains IK1, Egr2, Cmyb, E2F1 and YY1 putative transcription factor binding sites. Mutation of Egr2 or YY1 site led to 52-68% decrease of the mIRF-3 promoter activity, and double Egr2 and YY1 mutation reduced the promoter activity to 20% of the wild-type promoter activity. Furthermore, knockingdown of endogenous Egr2 or YY1 by a siRNA strategy markedly inhibited the mIRF-3 promoter activity. Chromatin immunoprecipitation assays showed that Egr2 and YY1 interact with the mIRF-3 promoter in vivo. These results suggested that the basal promoter activity of the mIRF-3 gene is regulated by transcription factors Egr2 and YY1 in NIH3T3 cells.

Association of IRF8 gene polymorphisms with autoimmune thyroid disease.

The occurrence of autoimmune thyroid disease (AITD) is known to have a major adverse effect on interferon (INF)-α treatment. The genetic variant of the INF regulatory factor 8 (IRF8), a type 1 INF regulator, is associated with susceptibility to systemic lupus erythematosus and multiple sclerosis. In this study, we investigated possible associations of the IRF8 polymorphisms, rs17445836 and rs2280381, with AITD in an ethnic Chinese population. In total, 278 patients with Graves' disease (GD) and 55 patients with Hashimoto's thyroiditis (HT), and 252 healthy controls were enrolled. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing were used for genotyping. Significantly lower frequencies of the GA genotype and A allele of rs17445836 were found in the HT group than in the control group (P=0·028, odds ratio (OR)=4·71 and P=0·022, OR=4·40, respectively). Both rs17445836 and rs2280381 were associated with the presence of an antimicrosomal antibody (AmiA), and rs2280381 was also associated with the presence of an antithyroglobulin antibody (ATA) in AITD. Moreover, rs17445836 was associated with the level of AmiA in AITD. rs17445836 of IRF8 is a possible genetic variant associated with the development of HT. rs17445836 was associated with the production of thyroid antibody, and the GG genotype of rs17445836 was associated with a higher AmiA titre than the GA genotype.

Reduced IRF7 response to rhinovirus unrelated with DNA methylation in peripheral mononuclear cells of adult asthmatics.

BackgroundHuman rhinoviruses are the major cause of asthma exacerbation in both children and adults. Recently, impaired antiviral interferon (IFN) response in asthmatics has been indicated as a primary reason of the susceptibility to respiratory virus, but the mechanism of defective IFN production is little understood to date. The expression of IFN regulatory factor 7 (IRF7), a transcriptional factor for virus-induced type I IFN production is known to be regulated epigenetically by DNA methylation.ObjectiveWe aimed to investigate the expression of IFN-α, IFN-β, and IRF7 in response to rhinovirus infection in the adult asthmatics and evaluate DNA methylation status of IRF7 gene promotor.MethodsTwenty symptomatic adult asthmatics and 10 healthy subjects were enrolled and peripheral blood was collected from each subject. Peripheral blood mononuclear cells (PBMCs) were isolated, cultured, and ex vivo stimulated with rhinovirus-16. The mRNA expressions of IFN-α, IFN-β, and IRF7 were analyzed using real time quantitative polymerase chain reaction. Genomic DNA was isolated from untreated PBMCs and the methylation status of IRF7 gene promotor was investigated using bisulfite pyrosequencing.ResultsThe mean age of asthmatics was 45.4 ± 15.7 years and 40% was male, which were not different with those of control group. Asthmatics showed significantly decreased mRNA expressions (relative expression to beta-actin) of IFN-α and IFN-β compared with normal control. The mRNA expression of IRF7 in the asthmatics was also significantly lower than those in the normal control. No significant difference of DNA methylation was observed between asthmatics and controls in all analyzed positions of IRF7 promotor CpG loci.ConclusionThe mRNA expression of type I IFN in response to rhinovirus was impaired in the PBMCs of adult asthmatics. The mRNA expression of IRF7, transcriptional factor inducing type I IFN was also reduced, but not caused by altered DNA methylation in the IRF7 gene promotor.

Regulation of myelopoiesis by the transcription factor IRF8.

Interferon regulatory factor-8 (IRF8) is a transcription factor expressed in hematopoietic cells, particularly in mononuclear phagocytes [monocytes/macrophages and dendritic cells (DCs)] and their progenitors. Various studies have demonstrated that IRF8 is essential for the development of monocytes, DCs, eosinophils, and basophils. Conversely, IRF8 suppresses the generation of neutrophils. Accordingly, Irf8 (-/-) mice develop immunodeficiency and a chronic myeloid leukemia (CML)-like disease. Mutations and loss of expression of the human IRF8 gene are also associated with immunodeficiency and CML, respectively. Recent findings have begun to reveal the transcription factor network and epigenetic changes governed by IRF8. For example, in mononuclear phagocyte progenitors, IRF8 cooperates with PU.1 to promote the formation of promoter-distal enhancers to induce monocyte-related genes including the critical downstream transcription factor gene Klf4. On the other hand, IRF8 blocks C/EBPα activity to suppress the neutrophil differentiation program. Indeed, Irf8 (-/-) mononuclear phagocyte progenitors fail to efficiently generate monocytes and DCs and, instead, aberrantly give rise to neutrophils. This article provides an overview of recent advances in our understanding of the role of IRF8 in myelopoiesis and related diseases.

Review of the RNA Interference Pathway in Molluscs Including Some Possibilities for Use in Bivalves in Aquaculture

Generalised reviews of RNA interference (RNAi) in invertebrates, and for use in aquaculture, have taken for granted that RNAi pathways operate in molluscs, but inspection of such reviews show little specific evidence of such activity in molluscs. This review was to understand what specific research had been conducted on RNAi in molluscs, particularly with regard to aquaculture. There were questions of whether RNAi in molluscs functions similarly to the paradigm established for most eukaryotes or, alternatively, was it more similar to the ecdozoa and how RNAi may relate to disease control in aquaculture? RNAi in molluscs appears to have been only investigated in about 14 species, mostly as a gene silencing phenomenon. We can infer that microRNAs including let-7 are functional in molluscs. The genes/proteins involved in the actual RNAi pathways have only been rudimentarily investigated, so how homologous the genes and proteins are to other metazoa is unknown. Furthermore, how many different genes for each activity in the RNAi pathway are also unknown? The cephalopods have been greatly overlooked with only a single RNAi gene-silencing study found. The long dsRNA-linked interferon pathways seem to be present in molluscs, unlike some other invertebrates and could be used to reduce disease states in aquaculture. In particular, interferon regulatory factor genes have been found in molluscs of aquacultural importance such as Crassostrea, Mytilus, Pinctada and Haliotis. Two possible aquaculture scenarios are discussed, zoonotic norovirus and ostreid herpesvirus 1 to illustrate the possibilities. The entire field of RNAi in molluscs looks ripe for scientific exploitation and practical application.

Characterization and expression analyses of five interferon regulatory factor transcripts (Irf4a, Irf4b, Irf7, Irf8, Irf10) in Atlantic cod (Gadus morhua)

The interferon regulatory factor (IRF) family of genes encodes a group of transcription factors that have important roles not only in regulating the expression of Type I interferons (IFNs) and other genes in the IFN pathway, but also in growth, development and the regulation of oncogenesis. In this study, several IRF family members (Irf4a, Irf4b, Irf7, Irf8, Irf10) in Atlantic cod (Gadus morhua) were characterized at the cDNA and putative amino acid levels, allowing for phylogenetic analysis of these proteins in teleost fish, as well as the development of gene-specific primers used in RT-PCR and quantitative PCR (QPCR) analyses. Two Atlantic cod Irf10 splice variants were identified and their presence confirmed by sequencing of the Irf10 genomic region. RT-PCR showed that Irf7, Irf8 and both Irf10 transcripts were expressed in all 15 cod tissues tested, while Irf4a and Irf4b were absent in some tissues. QPCR analysis of spleen expression expanded upon this, and upon previous work. All IRF transcripts in the study were responsive to stimulation by the viral mimic poly(I:C), and all except Irf4a were responsive to exposure to formalin-killed Aeromonas salmonicida (ASAL). These IRF genes, thus, are likely important in the cod immune response to both viral and bacterial infections. Increased temperature (10 °C to 16 °C) was also observed to modulate the antibacterial responses of all IRF transcripts, and the antiviral responses of Irf4b and Irf10-v2. This research supports earlier studies which reported that elevated temperature modulates the expression of many immune genes in Atlantic cod.

Identification and characterization of the lamprey IRF gene

Interferon regulatory factors (IRFs) are named for their ability to bind to and regulate interferon genes when an organism becomes infected with a virus. Numerous studies have revealed the versatile and critical functions of IRFs. In this study, an IRF gene from Lampetra japonica was identified and analyzed using bioinformatic methods. The L. japonica IRF (Lj-IRF) shares high sequence homology with other vertebrate IRFs but low sequence homology with an ascidian IRF-like protein. We also used recombinant Lj-IRF protein (rLj-IRF) to immunize New Zealand rabbits to prepare specific anti-rLj-IRF polyclonal antibodies. Enzyme-linked immunosorbent assays (ELISAs) and Western blotting assays were performed to detect the valence and specificity of the antibody. FACS analysis revealed that the Lj-IRF protein was expressed in approximately 21.14% of leukocytes and 9.60% of supraneural body cells in L. japonica, with immunofluorescence staining indicating a cytoplasmic location. The immunohistochemistry results demonstrated that IRF is distributed in the epithelial cells of the heart, supraneural body, kidneys and gills but is not detectable in intestinals or oral gland tissues. However, the expression of IRF was upregulated in lamprey intestinal tissues upon stimulation with the rLj-HMGB1 protein. Lj-IRF gene expression levels were higher in the rLj-HMGB1-stimulated group than the control group, and the expression level of Lj-IRF was significantly increased in the intestines as determined by quantitative real-time PCR. These results provide a foundation for studying the origin and evolution of the innate immune system in lampreys.

Molecular characterization of interferon regulatory factor 1 in Bubalus bubalis.

Interferon regulatory factor 1 (IRF1) is functionally diverse in the regulation of immune response and is considered to be an important candidate gene for studying disease susceptibility in mammals. In this paper, we characterized the whole sequence of the IRF1 gene in river buffalo (Bubalus bubalis) and compared genomic and the amino acid sequences between different species. The buffalo IRF1 gene was 7099 bp long and organized into 10 exons and nine introns. Its molecular structure showed exactly the same number of exons (10) and introns (nine) in bovids, mice, horses, humans, and chickens. However, rats did not have exon 5, but had the largest exon 4, which suggests that exon 5 was incorporated into exon 4. The coding and the amino acid sequences of the gene showed that identity varied from 73 to 99% at the coding sequence level and from 61 to 100% at the amino acid level when compared with other mammals and chickens. Comparative analysis of the gene sequence between two different buffalo breeds, Murrah and Mediterranean, revealed six potential SNPs that are primarily located in the 5' and 3'UTRs.

Identification of orange-spotted grouper (Epinephelus coioides) interferon regulatory factor 3 involved in antiviral immune response against fish RNA virus

Interferon regulatory factor 3 (IRF3) is an important transcription factor which regulates the expression of interferon (IFN) and IFN-stimulated genes (ISGs) following virus recognition. In this study, a novel IRF3 gene was cloned from grouper Epinephelus coioides (EcIRF3) and its effects against Singapore grouper iridovirus (SGIV) and red spotted grouper nervous necrosis virus (RGNNV) was investigated. The full-length of EcIRF3 cDNA was composed of 2513 bp and encoded a polypeptide of 458 amino acids which shared 82% identity with European seabass (Dicentrarchus labrax). EcIRF3 contained three conserved domains including a DNA-binding domain (DBD), an IRF associated domain (IAD) and a serine-rich domain. Expression profile analysis revealed that EcIRF3 was abundant in head kidney, kidney, spleen and gill. Upon different stimuli in vitro, the transcript of EcIRF3 was significantly up-regulated after RGNNV infection or treatment with polyinosin-polycytidylic acid (poly I:C). During SGIV infection, the increase of the EcIRF3 transcription was only detected at the late stage, suggesting that EcIRF3 was differently regulated by different stimuli. Immune fluorescence assay indicated that the fluorescence signal of EcIRF3 was increased significantly after infection with RGNNV or treatment with poly I:C, but moderately at the late stage of SGIV infection. Reporter gene assay showed that EcIRF3 activated zebrafish type I IFN and type III IFN promoter in vitro. The viral gene transcription and virus production of RGNNV were significantly decreased in EcIRF3 overexpressing cells. However, the ectopic expression of EcIRF3 did not affect the gene transcription and virus production of SGIV. Moreover, the mRNA expression levels of type I IFN and IFN-inducible genes (MxI, ISG15 and ISG56) were increased in RGNNV infected EcIRF3 overexpressing cells compared to empty vector transfected cells. Together, our results demonstrated that IFN immune response mediated by grouper IRF3 was exerted crucial roles for fish RNA virus, but not for DNA virus replication.

Effects of the nuclear localization of the Npro protein of classical swine fever virus on its virulence in pigs

The Npro protein of classical swine fever virus (CSFV) is localized in the cytoplasm and nucleus. However, it is unknown whether the nuclear localization of Npro correlates with the virulence of CSFV in the host. Previously, we showed that the Npro protein fused with interferon regulatory factor 3 (IRF3) was present only in the cytoplasm. Here, we generated and evaluated a recombinant CSFV vSM-IRF3 harboring the IRF3 gene inserted into the Npro gene of the highly virulent CSFV Shimen strain. Compared to the even nuclear and cytoplasmic distribution of the enhanced green fluorescent protein (EGFP)-Npro fusion expressed by the recombinant CSFV EGFP-CSFV, vSM-IRF3 expressed an IRF3-Npro fusion protein that only was localized in the cytoplasm. vSM-IRF3 was markedly attenuated in vitro and in vivo, and the inoculated pigs were completely protected from lethal CSFV challenge, whereas the parental virus as well as EGFP-CSFV exhibited a typical virulent phenotype. Taken together, the nuclear localization of Npro plays a significant role in the CSFV replication and virulence.

Aberrant methylation and silencing of IRF8 expression in non-small cell lung cancer.

The aim of the present study was to investigate the aberrant methylation and altered expression of the interferon regulatory factor 8 (IRF8) gene in non-small cell lung cancer (NSCLC). Pyrosequencing assays were performed on 191 tumor specimens from NSCLC patients. The changes in IRF8 mRNA expression, prior to and following treatment with a demethylating agent and methylation itself, were examined in 13 lung cancer cell lines by quantitative polymerase chain reaction (qPCR) and pyrosequencing. IRF8 protein expression was examined in 94 of the 191 NSCLC specimens by immunohistochemical analysis. The IRF8 methylation level was significantly higher in the tumor tissues than in matched non-malignant lung tissues (P<0.0001). IRF8 was more frequently methylated in tumor tissues compared with matched non-malignant lung tissues, as defined by a predetermined cut-off value (P<0.0001). The IRF8 methylation level was strongly correlated with the change in mRNA expression in lung cancer cell lines and with the protein expression level in primary tumors. The IRF8 gene was more frequently methylated in patients without an epidermal growth factor receptor (EGFR) mutation than in patients with an EGFR mutation (P=0.015). IRF8 methylation correlated with recurrent prognosis in adenocarcinomas (log-rank test, P=0.048). IRF8 protein expression was frequently silenced in males, smokers, patients with non-adenocarcinoma or with wild-type EGFR, or in an advanced stage. IRF8 is often silenced by its methylation, which is a frequent event in NSCLC and, therefore, methylation of IRF8 may act as a prognostic marker for recurrence. Analysis of IRF8 methylation status may provide novel opportunities for improved prognosis and therapy of resected NSCLC.

Association of interferon regulatory factor 4 gene polymorphisms rs12203592 and rs872071 with skin cancer and haematological malignancies susceptibility: a meta-analysis of 19 case-control studies.

BackgroundResearch has indicated that the rs12203592 and rs872071 interferon regulatory factor 4 (IRF4) gene polymorphisms correlate with the risk of cancer, especially skin cancer and haematological malignancies, but the results remain controversial. To understand better the effects of these two polymorphisms on skin cancer and haematological malignancies susceptibility, a cumulative meta-analysis was performed.MethodsWe conducted a search using the PubMed and Web of Science databases for relevant case-control studies published before April 2014. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using fixed- or random-effects models where appropriate. Heterogeneity test, publication bias test, and sensitivity analysis were also performed.ResultsIn total, 11 articles comprised of 19 case–control studies were identified; five focused on the rs12203592 polymorphism with 7,992 cases and 8,849 controls, and six were on the rs872071 polymorphism with 3108 cases and 8300 controls. As for rs12203592, a significant correlation with overall skin cancer and haematological malignancies risk was found with the homozygote comparison model (OR = 1.566, 95% CI 1.087-2.256) and recessive model (OR = 1.526, 95% CI 1.107-2.104). For rs872071, a significantly elevated haematological malignancies risk was observed in all genetic models (homozygote comparison: OR = 1.805, 95% CI 1.402-2.323; heterozygote comparison: OR = 1.427, 95% CI 1.203-1.692; dominant: OR = 1.556, 95% CI 1.281-1.891; recessive: OR = 1.432, 95% CI 1.293-1.587; additive: OR = 1.349, 95% CI 1.201-1.515). Similarly, increased skin cancer and haematological malignancies risk was also identified after stratification of the SNP data by cancer type, ethnicity and source of controls for both polymorphisms.ConclusionsOur meta-analysis indicated that the rs12203592 and rs872071 IRF4 gene polymorphisms are associated with individual susceptibility to skin cancer and haematological malignancies. Moreover, the effect of the rs12203592 polymorphism on skin cancer risk was particularly prominent among Caucasians. Further functional research should be performed to validate the association.

The effect of interferon regulatory factor-1 on apoptosis regulation in osteosarcomawith different p53 status

Objective Detect the effects of interferon regulatory factor-1 (IRF-1) gene on the apoptosisregulation in osteosarcoma with different p53 status and disclose the underlying mechnisms preliminarily.Methods To observe the effects of IRF-1 gene on the apoptosis effects induced by chemotherapeutic agent adriamycin in steosarcoma with different p53 status,p53 +/+ U2OS and p53-/-SaOS-2 were used.Western blotting analysis was firstly used to detect the expression of IRF-1 protein in adriamycin treated p53 +/+ U2OS and p53-/-SaOS-2 cells.And then IRF-1 gene was further overexpressed or knocked out for further detection the apoptosis effect induced by adriamycin respectively.Meanwhile,the target genes of p53,B cell lymphoma/leukemia-2 associated X protein (bax) and p21,were detected by real-time reverse transcriptase-polymerase chain reaction (RT-qPCR).Results Western blotting showed that the expression of IRF-1 has been improved significantly when p53 +/+ U2OS and p53-/-SaOS-2 were treated with adriamycin for 24 h.The significant increase in the death rate of cells has been detected by the release of lactate dehydrogenase (LDH) Activity (P ＜ 0.05).When IRF-1 gene were overexpressed with transient transfection,adriamycin-induced apoptosis effect were increased significantly (P ＜ 0.05),while the knockdown of IRF-1 gene by small interfering RNA (siRNA) transfection were decreased significantly (P ＜ 0.05).RT-qPCR were used to further detected the expression of downstream target genes bax and p21,which do great favor to p53-dependent apoptosis.The results showed that bax and p21 were both upregulated significantly in p53-/-osteosarcoma cells (P ＜ 0.05),but not observed in p53 +/+ osteosarcoma cells (P ＞ 0.05).Conclusion IRF-1 plays a crucial role in adrymycin induced apoptosis by modulating p53 target genes,especially to the cancer cells with p53 gene deficient. Key words: Interferon regulatory factor-1 ; Osteosarcoma cells ; p53 ; Apoptosis

Sublytic C5b-9 triggers glomerular mesangial cell apoptosis via XAF1 gene activation mediated by p300-dependent IRF-1 acetylation.

The apoptosis of glomerular mesangial cells (GMCs) in rat Thy-1 nephritis (Thy-1N), a model of human mesangioproliferative glomerulonephritis (MsPGN), is accompanied by sublytic C5b-9 deposition. However, the mechanism by which sublytic C5b-9 induces GMC apoptosis is unclear. In the present studies, the effect of X-linked inhibitor of apoptosis-associated factor 1 (XAF1) expression on GMC apoptosis and the role of p300 and interferon regulatory factor-1 (IRF-1) in mediating XAF1 gene activation were determined, both in the GMCs induced by sublytic C5b-9 (in vitro) and in the renal tissues of rats with Thy-1N (in vivo). The in vitro studies demonstrated that IRF-1-enhanced XAF1 gene activation and its regulation by p300-mediated IRF-1 acetylation were involved in GMC apoptosis induced by sublytic C5b-9. The element of IRF-1 binding to XAF1 promoter and two acetylated sites of IRF-1 protein were also revealed. In vivo, silence of p300, IRF-1 or XAF1 genes in the renal tissues diminished GMC apoptosis and secondary GMC proliferation as well as urinary protein secretion in Thy-1N rats. Together, these data implicate that sublytic C5b-9 induces the expression of both p300 and IRF-1, as well as p300-dependent IRF-1 acetylation that may contribute to XAF1 gene activation and subsequent GMC apoptosis in Thy-1N rats.

No evidence for a genetic association of IRF4 with systemic lupus erythematosus in a Chinese population

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with immunological defects caused by abnormal immune regulation and excessive production of autoantibodies. Interferon regulatory factor 4 (IRF4) as a lymphocyte-restricted member of the IRF family is expressed exclusively in immune system cells and is essential for the development of T helper-2 (Th2) cells, IL17-producing T helper (Th17) cells, and IL9-producing T helper (Th9) cells. Some studies have shown that IRF4 is important in the development of autoimmune diseases. The role of IRF4 in human SLE has not been extensively studied. This article will discuss the relationship between the IRF4 gene polymorphism (single nucleotide polymorphism rs872071) and the susceptibility to SLE in a Chinese Han population. A case-control study was performed with 663 SLE patients and 658 healthy controls. The results showed that IRF4 gene polymorphism (rs872071) was not significantly different between SLE patients and healthy controls [A/G vs. G/G: p = 0.543, odds ratio (OR) = 0.872, 95 % confidence interval (CI) 0.562-1.355; G vs. A: p = 0.512, OR = 1.058, 95 % CI 0.893-1.254; A/A + A/G vs. G/G: p = 0.475, OR = 0.857, 95 % CI 0.562-1.308]. Similarly, in a subgroup analysis of clinical manifestation of lupus nephritis (LN), no significant differences were found between the non-LN group and the LN group (G/G vs. A/G vs. A/A: χ(2) = 0.611, p = 0.631; G vs. A: χ(2) = 0.411, p = 0.521).These findings suggest that the IRF4 gene polymorphism is not associated with SLE in a Chinese Han population; further studies are needed to establish the role of IRF4 in SLE with a larger sample size.

Copy Number Abnormalities Of The Interferon Regulatory Factor-4 (IRF4) Gene Are Associated With IRF4/MUM1 Expression In Peripheral T-Cell Lymphomas

BackgroundPeripheral T-cell lymphomas (PTCLs) are aggressive non-Hodgkin lymphomas with poor overall survival rates. The genetics of PTCLs are poorly understood. We have described t(6;14)(p25.3;q11.2) translocations in PTCLs involving the T-cell receptor-alpha (TRA@) and interferon regulatory factor-4 (IRF4) genes and overexpressing IRF4 protein (also called MUM1). IRF4/MUM1 is a lymphoid transcription factor involved in differentiation and growth, the expression of which is tightly regulated in normal T cells. However, nearly half of PTCLs constitutively express IRF4/MUM1 and this expression is associated with adverse overall survival in several PTCL subtypes. Because IRF4/TRA@ translocations are rare among PTCLs (<1%), we investigated the presence of other genetic abnormalities of IRF4 in PTCLs and examined their association with IRF4/MUM1 protein expression. MethodsStudies were performed on paraffin tissue sections of PTCL specimens diagnosed by standard WHO criteria. IRF4/MUM1 immunohistochemical staining (IHC) was performed using the MUM1p antibody and considered positive if nuclear staining was present in >30% of tumor cell nuclei. Fluorescence in situ hybridization (FISH) was performed using breakapart probes constructed from bacterial artificial chromosome DNA that hybridized to loci flanking the IRF4 locus on 6p25.3. Cases with 3 or more fusion signals were considered to have extra copies of the IRF4 gene. In a subset of cases, PCR and Sanger sequencing was performed on DNA extracted from frozen PTCL tumor tissue with primer sets that amplified exons 1 to 10 of the IRF4 gene. Data were analyzed using the chi-square test or t test. ResultsPTCLs from 277 patients (175 M:102 F; median age, 61 y) were examined by both IHC and FISH. The subtype distribution was: PTCL, not otherwise specified (NOS), 93; anaplastic large cell lymphoma (ALCL), 89; angioimmunoblastic T-cell lymphoma (AITL), 27; cutaneous T-cell lymphoma (CTCL), 43; and cytotoxic PTCL, 25. IRF4/MUM1 was positive in 116 cases (42%). Extra copies of IRF4 were identified in 18 PTCLs (7%), 83% of which were IRF4/MUM1 protein-positive. In contrast, 39% of cases without extra copies of IRF4 were IRF4/MUM1 protein-positive (p=0.0002). The mean percentage of tumor cells with IRF4/MUM1 staining was 69% in cases with extra copies of IRF4, compared to 30% in cases without extra copies (p=0.0001). Extra copies of IRF4 were seen in 13% of ALCLs, 4% each of PTCLs, NOS and cytotoxic PTCLs, 2% of CTCLs, and 0% of AITLs (p=0.02). Two IRF4/MUM1-positive cases had an IRF4/TRA@ translocation (1%). We selected 30 IRF4/MUM1-positive PTCLs for Sanger sequencing. In this subset, we identified a previously undescribed non-synonymous variant in exon 5 (S309R) in 1 case (3%) without an extra copy of IRF4. ConclusionsExtra copies of IRF4 are seen in ∼7% of PTCLs, are significantly associated with IRF4/MUM1 expression, and are preferentially observed in ALCLs. Both IRF4/TRA@ translocations and IRF4 mutations are rare in PTCLs. These data suggest that genetic abnormalities of the IRF4 gene – specifically extra copies of IRF4 – may contribute to IRF4/MUM1 expression in some PTCLs. Since IRF4/MUM1 expression is seen in ∼42% of PTCLs, these data also imply the existence of other regulatory mechanisms. Characterizing these mechanisms may be important clinically, since IRF4/MUM1 has been proposed as a therapeutic target in human cancers but drugs that directly inhibit its function are currently not available. Disclosures:No relevant conflicts of interest to declare.

NK Cells From CLL Patients Exhibit Down-Regulation Of Interferon Response Genes That Can Be Reversed With Lenalidomide

Chronic lymphocytic leukemia (CLL) is associated with profound defects in immune function, resulting in failure of anti-tumor immunity and increased susceptibility to infection. We have previously demonstrated alterations in gene expression profiles of T cells from CLL patients, which translate into functional defects in T-cell immune synapse formation, motility and cytotoxicity (Gorgun et al. JCI 2005; Ramsay et al. JCI 2008, Blood 2013). However a comparison of the transcriptome of natural killer (NK) cells from CLL patients and controls has not been investigated. NK cells were isolated from the peripheral blood of patients with CLL and healthy donors, followed by gene expression profiling using the Affymetrix U133Plus2.0 platform. 117 probes showed a >2-fold decrease in expression while only 18 probes showed a >2-fold increase in expression (adjusted p-value < 0.05) in CLL NK cells compared to healthy donor NK cells. Strikingly, 52 out of the 117 significantly down-regulated probes (44.4%) were for interferon-inducible genes including STAT1 (Signal Transducers and Activator 1), SOCS1 (Suppressor of cytokine signaling 1), interferon regulatory factor genes IRF7 and IRF9, and oligoadenylate synthetase genes OAS1, OAS2, and OAS3. The majority of these genes were inducible by both type 1 and type 2 interferons. Many of these genes have been implicated in host immunity to viral infections, and so it is possible that decreased NK-cell responsiveness to interferon contributes to the increased susceptibility of CLL patients to viruses. Notably, there was also altered expression of signaling pathways in common with T cells from CLL patients, with dysregulation of the cytoskeleton genes RAB3GAP1, RAB38, and EPHA1 and down-regulation of JUN mirroring the dysregulated JNK-signaling and the altered actin cytoskeleton pathways we have found in T cells from CLL patients. These changes were not due to differences in the relative frequencies of CD56DIM and CD56BRIGHTNK cells.Lenalidomide has significant clinical activity in CLL. It is not directly toxic to tumor cells in vitro, but instead is thought to activate anti-tumor immunity and block pro-tumor micro-environmental factors. NK-cell proliferation has been shown to correlate with clinical response to lenalidomide in CLL (Chanan Khan et al. BJ Haem 2011). Therefore, we investigated the effect of lenalidomide treatment on the gene expression profiles of NK cells from CLL patients in comparison to healthy controls. PBMCs from CLL patients or healthy controls were cultured in the presence of 1μM lenalidomide or vehicle control for 48 hours, followed by NK-cell isolation, RNA extraction and gene expression profiling. There were striking differences in the effect of lenalidomide on NK cells from CLL patients compared with healthy NK cells. In CLL NK cells, lenalidomide repaired the down-regulation of interferon-inducible genes, by increasing the expression of genes such as OAS3, IFIT1, IFI44L, IFIT3, OAS1, PDK4, and ACTN1. Pathway analysis highlighted the effect of lenalidomide on inducing interferon signaling, showing significant activation of interferon α, γ, and λ as upstream regulators. While many of the interferon-inducible genes were up-regulated >3-fold in CLL NK cells, only OAS3 was significantly up-regulated in healthy NK cells with lenalidomide. Furthermore, the gene for IFNγ, IFNG, was actually significantly down-regulated in healthy NK cells by this agent. Lenalidomide also significantly down-regulated the expression of 5 genes encoding killer-cell immunoglobulin-like receptors (KIRs): KIR2DL1, KIR2DL2, KIR2DS3, KIR2DS4, and KIR3DL2, in healthy NK cells, but did not significantly down-regulate KIR genes in the CLL NK-cell dataset. Lenalidomide treatment did have some overlapping effects on CLL and healthy NK cells, including up-regulation of genes ARL11, CYFIP, and CORO1B that regulate the actin cytoskeleton pathway.In conclusion, NK cells from CLL patients have down-regulation of interferon response genes and pathways known to regulate normal immune function in response to bacteria and viruses. Lenalidomide has a differential effect on CLL and healthy NK cells: in CLL NK cells it repairs defective interferon responses, whereas in healthy NK cells it down-regulates inhibitory pathways. Disclosures:Riches:Celgene: Research Funding. Gribben:Celgene: Research Funding; Pharmacyclics: Honoraria; Roche: Honoraria.

The Editor takes a closer look at some of this month's articles

Clinical & Experimental AllergyVolume 43, Issue 10 p. 1091-1091 Editor's ChoiceFree Access The Editor takes a closer look at some of this month's articles First published: 16 September 2013 https://doi.org/10.1111/cea.12190AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Maternal Vitamin D: no association with allergic outcomes in offspring The debate about the role of vitamin D and allergic disease continues to attract a lot of attention 1. Wills and colleagues (pp. 1180–1188) contribute to the discussion with a large epidemiological study of white caucasians relating maternal vitamin D levels to a range of allergic outcomes in their offspring up to 9 years of age. No relationship was found with any allergy related outcome. Only 5% of mothers were deficient in vitamin D with ~30% having insufficient levels of the vitamin. While this study doesn't therefore exclude the possibility that severe vitamin D deficiency can lead to an increased risk of allergic disease, it would seem unlikely that there is a strong link between maternal vitamin D and the risk of childhood allergy. Dr. Andrew Wills Vitamin D Structure (Photo credit: Nwanneka123/Wikimedia Commons). Interferon regulatory factor 1: a role in bronchitis but not asthma? Interferon regulatory factor 1 (IRF-1) is a member of a family of transcription factors that regulate interferon β1 and interferon γ expression as well a differentiation of T cells. Pinto et al. (pp. 1152–1159), demonstrate in this issue a link between polymorphisms in the IRF-1 gene and the risk of developing bronchitis in two cohorts of children. Associations with asthma and airway hyperresponsiveness (AHR) were found in one cohort but not the replication cohort (AHR was not measured). The odds ratios were modest, but it is interesting that the authors were able to genetically dissociate asthma from recurrent bronchitis. This emphasizes that the factors that control airway responses to viruses in childhood are distinct from those associated with asthma. It would be interesting to link the IRF-1 genotype with the endotypes of childhood asthma which are being revealed by epidemiological studies of childhood wheeze 2, 3. Professor Leonardo A. Pinto IRF4 gene map (yellow) with 9 exons (rectangles) and the 3UTR (grey). [See figure 1 in L. A. Pinto et al. (pp. 1152–1159)]. Egg allergy: to challenge or not to challenge Egg allergy is common in early childhood with large effects on dietary restriction. Many children who react to lightly cooked egg can tolerate egg contained in baked products. At the moment only a challenge test can reliably distinguish between the two types of reaction which is burdensome both for the doctor and parent-child. Tan et al. (pp. 1189–1195) have asked whether skin prick tests using either baked muffin or ovomucoid are sufficiently predictive to avoid the need for challenge with a baked egg product. They show that a < 2 mm reaction to the muffin meant that there was an 88% chance of a negative challenge and perhaps even more usefully if there was a > 11 mm wheal to ovomucoid there was a 100% chance of a positive challenge. The practical implications of this for allergist and parent are discussed in an excellent editorial by Wanda Phipatanakul (pp. 1095–1096). Dr. John W Tan Professor Wanda Phipatanakul Blueberry muffin (Photo credit: NCI, Renee Cornet/Wikimedia Commons). References 1Reinholz M, Ruzicka T, Schauber J. Vitamin D and its role in allergic disease. Clin Exp Allergy 2012; 42: 817– 26. 2Spycher BD, Silverman M, Kuehni CE. Phenotypes of childhood asthma: are they real? Clin Exp Allergy 2010; 40: 1130– 41. 3Caliskan M, Bochkov YA, Kreiner-Moller E et al. Rhinovirus wheezing illness and genetic risk of childhood-onset asthma. N Engl J Med 2013; 368: 1398– 407. Caption to cover illustration: House dust mites (Dermatophagoides pteronyssinus), by photographer Gilles San Martin/Wikimedia Commons. This logo highlights the Editor's Choice articles on the cover and the first page of each of the articles. Volume43, Issue10October 2013Pages 1091-1091 ReferencesRelatedInformation