Type I and III interferons (IFNs) activate similar downstream signaling cascades, but unlike type I IFNs, type III IFNs (IFNl) do not elicit strong inflammatory responses in vivo. Here, we examined the molecular mechanisms underlying this disparity. Type I and III IFNs displayed kinetic differences in expression of IFN-stimulated genes and proinflammatory responses, with type I IFNs preferentially stimulating expression of the transcription factor IRF1. Type III IFNs failed to induce IRF1 expression because of low IFNl receptor abundance and insufficient STAT1 activation on epithelial cells and thus did not activate the IRF1 proinflammatory gene program. Rather, IFNl stimulation preferentially induced factors implicated in tissue repair. Our findings suggest that IFN receptor compartmentalization and abundance confer a spatiotemporal division of labor where type III IFNs control viral spread at the site of the infection while restricting tissue damage; the transient induction of inflammatory responses by type I IFNs recruits immune effectors to promote protective immunity.

Natural killer (NK) cells play an important role in the detection and elimination of tumors and virus-infected cells by the innate immune system. Human NK cells use cell surface receptors (KIR) for class I MHC to sense alterations of class I on potential target cells. Individual NK cells only express a subset of the available KIR genes, generating specialized NK cells that can specifically detect alteration of a particular class I molecule or group of molecules. The probabilistic behavior of human KIR bi-directional promoters is proposed to control the frequency of expression of these variegated genes. Analysis of a panel of donors has revealed the presence of several functionally relevant promoter polymorphisms clustered mainly in the inhibitory KIR family members, especially the KIR3DL1 alleles. We demonstrate for the first time that promoter polymorphisms affecting the strength of competing sense and antisense promoters largely explain the differential frequency of expression of KIR3DL1 allotypes on NK cells. KIR3DL1/S1 subtypes have distinct biological activity and coding region variants of the KIR3DL1/S1 gene strongly influence pathogenesis of HIV/AIDS and other human diseases. We propose that the polymorphisms shown in this study to regulate the frequency of KIR3DL1/S1 subtype expression on NK cells contribute substantially to the phenotypic variation across allotypes with respect to disease resistance.

Two recent genome-wide association studies have independently identified a prostate cancer susceptibility locus on chromosome 10q11.2. The most significant single-nucleotide polymorphism (SNP) marker reported, rs10993994, is 57 bp centromeric of the first exon of the MSMB gene, which encodes ␤-microseminoprotein (prostatic secretory protein 94). In this study, a fine-mapping analysis using HapMap SNPs was conducted across a Ϸ65-kb region (chr10: 51168330 -51234020) flanking rs10993994 with 13 tag SNPs in 6,118 prostate cancer cases and 6,105 controls of European origin from the Cancer Genetic Markers of Susceptibility (CGEMS) project. rs10993994 remained the most strongly associated marker with prostate cancer risk [P ‫؍‬ 8.8 ؋ 10 ؊18 ; heterozygous odds ratio (OR) ‫؍‬ 1.20, 95% confidence interval (CI): 1.11-1.30; homozygous OR ‫؍‬ 1.64, 95% CI: 1.47-1.86 for the adjusted genotype test with 2 df]. In follow-up functional analyses, the T variant of rs10993994 significantly affected expression of in vitro luciferase reporter constructs. In electrophoretic mobility shift assays, the C allele of rs10993994 preferentially binds to the CREB transcription factor. Analysis of tumor cell lines with a CC or CT genotype revealed a high level of MSMB gene expression compared with cell lines with a TT genotype. These findings were specific to the alleles of rs10993994 and were not observed for other SNPs determined by sequence analysis of the proximal promoter. Together, our mapping study and functional analyses implicate regulation of expression of MSMB as a plausible mechanism accounting for the association identified at this locus. Further investigation is warranted to determine whether rs10993994 alone or in combination with additional variants contributes to prostate cancer susceptibility.genome-wide association studies ͉ prostate cancer genetics ͉ CREB transcription factor P rostate cancer is the most common noncutaneous malignancy and the second leading cause of cancer-related deaths of men in the developed world, with an incidence of Ϸ170 per 100,000 in the United States (1). Well-established risk factors include age, ethnicity, and family history (2), and although it is believed that genetic factors contribute to disease etiology, until recently, there have been few validated genetic candidates associated with prostate cancer risk. To date, many hypothesis-based candidate gene studies have been performed, but none have been convincingly replicated; most were underpowered or had design problems (3).

Differential HLA-C levels influence several human diseases, but the mechanisms responsible are incompletely characterized. Using a validated prediction algorithm, we imputed HLA-C cell surface levels in 228 individuals from the 1000 Genomes dataset. We tested 68,726 SNPs within the MHC for association with HLA-C level. The HLA-C promoter region variant, rs2395471, 800 bp upstream of the transcription start site, gave the most significant association with HLA-C levels (p = 4.2 × 10). This imputed expression quantitative trait locus, termed impeQTL, was also shown to associate with HLA-C expression in a genome-wide association study of 273 donors in which HLA-C mRNA expression levels were determined by quantitative PCR (qPCR) (p = 1.8 × 10) and in two cohorts where HLA-C cell surface levels were determined directly by flow cytometry (n = 369 combined, p < 10). rs2395471 is located in an Oct1 transcription factor consensus binding site motif where the A allele is predicted to have higher affinity for Oct1 than the G allele. Mobility shift electrophoresis demonstrated that Oct1 binds to both alleles in vitro, but decreased HLA-C promoter activity was observed in a luciferase reporter assay for rs2395471_G relative to rs2395471_A on a fixed promoter background. The rs2395471 variant accounts for up to 36% of the explained variation of HLA-C level. These data strengthen our understanding of HLA-C transcriptional regulation and provide a basis for understanding the potential consequences of manipulating HLA-C levels therapeutically.

4,5 Therefore, an elucidation of the factors that influence KIR gene transcription and a more thorough understanding of how KIR signaling affects NK-cell development are needed to understand how to manipulate the innate immune system for therapeutic purposes.Progress in the elucidation of how KIR genes are regulated has been limited because of the complexity of the KIR gene locus and the fact that KIR genes are not present in model rodent species, which are amenable to genomic manipulation. The conventional 250-bp core promoter located in the 5Ј region just proximal to the translational start site has been characterized in detail for many KIR genes. 6-8 However, an entire 2-kb intergenic region exists upstream of the translational start site for each KIR gene, with the exception of KIR2DL4, which has a 14-kb upstream intergenic region. 9 A recent report has identified the presence of active distal KIR promoter elements and spliced transcripts originating from these elements. 10 Because the distal promoter contains a Myc-binding site, 10 we hypothesized that c-Myc can bind to the distal promoter element and directly affect KIR expression. c-Myc is a basic helix-loophelix leucine zipper transcription factor that binds E-box DNA motifs as a heterodimer with Max, resulting in transcriptional activation or silencing of target genes. 11-13 Many major cellular processes, including cell cycle entry, 14 proliferation, 15 cell size regulation, 16 and apoptosis, 17 are influenced by c-Myc. 18,19 c-Myc is particularly interesting in the context of KIR transcriptional regulation because c-Myc functions as a downstream component of the interleukin-15 (IL-15) signaling pathway during CD8 ϩ T-cell homeostasis, 20 and the IL-15 pathway is critical for NK-cell maturation, 21 activation on infection in the periphery, 22 and homeostasis. 23 In the present study, we demonstrate a direct, functional interaction between c-Myc induced by IL-15 and the distal KIR promoter element and show that full-length KIR transcripts are transcribed from the distal promoter element early during development of the NK-cell KIR repertoire. MethodsElectric mobility shift assay of c-Myc binding to the distal KIR promoter element Nuclear extracts were prepared from YT-Indy cells using the CellLytic NuCLEAR extraction kit (Sigma-Aldrich, St Louis, MO). Protein concentration was measured with a Bio-Rad protein assay (Hercules, CA), and

The HLA-C gene appears to have evolved in higher primates to serve as a dominant source of ligands for the KIR2D family of inhibitory MHC class I receptors. The expression of NK cell-intrinsic MHC class I has been shown to regulate the murine Ly49 family of MHC class I receptors due to the interaction of these receptors with NK cell MHC in cis. However, cis interactions have not been demonstrated for the human KIR and HLA proteins. We report the discovery of an elaborate NK cell-specific system regulating HLA-C expression, indicating an important role for HLA-C in the development and function of NK cells. A large array of alternative transcripts with differences in intron/exon content are generated from an upstream NK-specific HLA-C promoter, and exon content varies between HLA-C alleles due to SNPs in splice donor/acceptor sites. Skipping of the first coding exon of HLA-C generates a subset of untranslatable mRNAs, and the proportion of untranslatable HLA-C mRNA decreases as NK cells mature, correlating with increased protein expression by mature NK cells. Polymorphism in a key Ets-binding site of the NK promoter has generated HLA-C alleles that lack significant promoter activity, resulting in reduced HLA-C expression and increased functional activity. The NK-intrinsic regulation of HLA-C thus represents a novel mechanism controlling the lytic activity of NK cells during development.

A conserved regulatory element in intron 1 of UNC13D regulates Munc13-4 expression.

Recognition of microbial components via innate receptors including the C-type lectin receptor Dectin-1, together with the inflammatory environment, programs dendritic cells (DCs) to orchestrate the magnitude and type of adaptive immune responses. The exposure to β-glucan, a known Dectin-1 agonist and component of fungi, yeasts, and certain immune support supplements, activates DCs to induce T helper (Th)17 cells that are essential against fungal pathogens and extracellular bacteria but may trigger inflammatory pathology or autoimmune diseases. However, the exact mechanisms of DC programming by β-glucan have not yet been fully elucidated. Using a gene expression/perturbation approach, we demonstrate that in human DCs β-glucan transcriptionally activates via an interleukin (IL)-1- and inflammasome-mediated positive feedback late-induced genes that bridge innate and adaptive immunity. We report that in addition to its known ability to directly prime T cells toward the Th17 lineage, IL-1 by promoting the transcriptional cofactor inhibitor of κB-ζ (IκB-ζ) also programs β-glucan-exposed DCs to express cell adhesion and migration mediators, antimicrobial molecules, and Th17-polarizing factors. Interferon (IFN)-γ interferes with the IL-1/IκB-ζ axis in β-glucan-activated DCs and promotes T cell-mediated immune responses with increased release of IFN-γ and IL-22, and diminished production of IL-17. Thus, our results identify IL-1 and IFN-γ as regulators of DC programming by β-glucan. These molecular networks provide new insights into the regulation of the Th17 response as well as new targets for the modulation of immune responses to β-glucan-containing microorganisms.