Project description:Lambda interferons (IFN?s, type III IFNs or interleukins-28/29) were described fifteen years ago as novel cytokines sharing structural and functional homology with IL-10 and type I IFNs, respectively. IFN?s engage a unique receptor complex comprising IFNLR1 and IL10R2, nevertheless they share signaling cascade and many functions with type I IFNs, questioning their possible non-redundant roles and overall biological importance. Here, we review the latest evidence establishing the primacy of IFN?s in front line protection at anatomical barriers, mediating antiviral immunity before type I IFNs. We also discuss their emerging role in regulating inflammation and limiting host damage, a major difference to type I IFNs. IFN?s come thus to light as dual function cytokines mediating antiviral immunity and damage control.
Project description:Balanced production of type I interferons and proinflammatory cytokines after engagement of Toll-like receptors (TLRs), which signal through adaptors containing a Toll-interleukin 1 receptor (TIR) domain, such as MyD88 and TRIF, has been proposed to control the pathogenesis of autoimmune disease and tumor responses to inflammation. Here we show that TRAF3, a ubiquitin ligase that interacts with both MyD88 and TRIF, regulated the production of interferon and proinflammatory cytokines in different ways. Degradative ubiquitination of TRAF3 during MyD88-dependent TLR signaling was essential for the activation of mitogen-activated protein kinases (MAPKs) and production of inflammatory cytokines. In contrast, TRIF-dependent signaling triggered noncanonical TRAF3 self-ubiquitination that activated the interferon response. Inhibition of degradative ubiquitination of TRAF3 prevented the expression of all proinflammatory cytokines without affecting the interferon response.
Project description:HIV-1 replication in macrophages can be regulated by cytokines and infection is restricted in macrophages activated by type I interferons and polarizing cytokines. Here, we observed that the expression levels of the cellular factors Trim5?, CypA, APOBEC3G, SAMHD-1, Trim22, tetherin and TREX-1, and the anti-HIV miRNAs miR-28, miR-150, miR-223 and miR-382 was upregulated by IFN-? and IFN-? in macrophages, which may account for the inhibiting effect on viral replication and the antiviral state of these cells. Expression of these factors was also increased by IFN-? +/- TNF-?, albeit to a lesser extent; yet, HIV-1 replication in these cells was not restricted at the level of proviral synthesis, indicating that these cellular factors only partially contribute to the observed restriction. IL-4, IL-10 or IL-32 polarization did not affect the expression of cellular factors and miRNAs, suggesting only a limited role for these cellular factors in restricting HIV-1 replication in macrophages.
Project description:The effect of human immunodeficiency virus (HIV) infection and high-level HIV replication on the function of monocytes was investigated. HIV-positive patients had elevated levels of spontaneous production of some or all of the monocyte proinflammatory cytokines measured (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor alpha [TNF-alpha]) compared to uninfected controls. In patients on therapy with high frequencies of monocytes producing proinflammatory cytokines, this frequency was diminished in the context of viremia during an interruption of therapy. Diminished production of proinflammatory cytokines during viremia was restored by culture with autologous CD4(+) T cells or monocytes from an on-therapy time point or lipopolysaccharide (LPS). Microarray analysis demonstrated that diminished monocyte production of proinflammatory cytokines was correlated with elevated type I interferon-stimulated gene transcripts. The addition of exogenous alpha 2A interferon diminished the spontaneous production of IL-1beta, IL-6, and TNF-alpha but did not affect responses to LPS, recapitulating the changes observed for HIV-viremic patients. These results suggest that monocyte function is diminished during high-level HIV viremia and that this effect is mediated by chronic stimulation by type I interferons. This effect on monocytes during viremia may play a role in diminished innate or adaptive immune system functions in HIV-infected patients. In addition, the restoration of these functions may also play a role in some immune reconstitution syndromes observed during initiation of therapy.
Project description:Cross-regulation of Toll-like receptor (TLR) responses by cytokines is essential for effective host defense, avoidance of toxicity and homeostasis, but the underlying mechanisms are not well understood. Our comprehensive epigenomics approach to the analysis of human macrophages showed that the proinflammatory cytokines TNF and type I interferons induced transcriptional cascades that altered chromatin states to broadly reprogram responses induced by TLR4. TNF tolerized genes encoding inflammatory molecules to prevent toxicity while preserving the induction of genes encoding antiviral and metabolic molecules. Type I interferons potentiated the inflammatory function of TNF by priming chromatin to prevent the silencing of target genes of the transcription factor NF-?B that encode inflammatory molecules. The priming of chromatin enabled robust transcriptional responses to weak upstream signals. Similar chromatin regulation occurred in human diseases. Our findings reveal that signaling crosstalk between interferons and TNF is integrated at the level of chromatin to reprogram inflammatory responses, and identify previously unknown functions and mechanisms of action of these cytokines.
Project description:Type I Interferons encompasses a large family of closely related cytokines comprising of at least 13 IFN-α isotypes and single IFN-β. Both IFN-α and IFN-β exert their activity through a common receptor IFNAR. Type I Interferons have broad regulatory effects and various subtypes of dendritic cells are influenced by this cytokines. In our study we asked question whether the low, constitutive levels of type I Interferons produced under steady state conditions are important for proper function of splenic conventional dendritic cells. In this approach we sorted out two populations (CD8α+ and CD8α-) of splenic dendritic cells (DCs) from untreated WT, IFN-β-/- and IFNAR-/- C57Bl/6 mice. All mice were between 8-10 weeks old. Further we isolated RNA and performed microarray analysis. Each DCs population was repeated twice.
Project description:Inflammation is an essential physiological process, which enables survival during infection and maintains tissue homeostasis. Interferons (IFNs) and pro- and anti-inflammatory cytokines are crucial for appropriate response to pathogens, damaged cells, or irritants in inflammatory response. The inflammasom is multiprotein complex, which initiates cleavage of pro-inflammatory cytokines IL-1β and IL-18 into active forms. In addition, inflammasomes initiate pyroptotic cell death. In the present review, I summarize and analyze recent findings regarding the cross talk of IFNs and inflammasomes.
Project description:Primary RNAseq data from carefully sorted immunocyte populations, sequenced using ImmGen's SOP for 'ultra-low-input' population RNAseq (typically 500 to 1,000 cells) performed by Smartseq2. Overall design: This Superseries is an umbrella for all datasets generated by ImmGen labs using a joint low-input population RNAseq protocol. The actual datasets that use this joint protocol are listed below. In practice, cell samples collected across ImmGen participating labs (or collaborating labs for OpenSource projects) are prepared to very high purity (2 rounds or more of cell sorting) using the ImmGen SOP (immgen.org; see below). After direct lysis, samples are frozen and shipped to the ImmGen Core team for common library construction and sequencing using ImmGen's standard RNA-seq (SmartSeq2) pipeline at the Broad Institute’s Technology Lab. After the final sort of 500 to 1,000 cells directly into 5ul lysis buffer (TCL Buffer (Qiagen) with 1% 2- Mercaptoethanol), Smart-seq2 libraries were prepared as previously described (Picelli et al., 2013; Picelli et al., 2014) with slight modifications. Briefly, total RNA was captured and purified on RNAClean XP beads (Beckman Coulter). Polyadenylated mRNA was then selected using an anchored oligo(dT) primer (5'AAGCAGTGGTATCAACGCAGAGTACT30VN-3') and converted to cDNA via reverse transcription. First strand cDNA was subjected to limited PCR amplification followed by Tn5 transposon based fragmentation using the Nextera XT DNA Library Preparation Kit (Illumina). Samples were then PCR amplified for 18 cycles using barcoded primers such that each sample carries a specific combination of eight base Illumina P5 and P7 barcodes and pooled together prior to Smart sequencing. Smart-seq paired-end sequencing was performed on an Illumina NextSeq500 using 2 x 25bp reads with no further trimming.
Project description:Type I Interferons encompasses a large family of closely related cytokines comprising of at least 13 IFN-α isotypes and single IFN-β. Both IFN-α and IFN-β exert their activity through a common receptor IFNAR. Type I Interferons have broad regulatory effects and various subtypes of dendritic cells are influenced by this cytokines. In our study we asked question whether the low, constitutive levels of type I Interferons produced under steady state conditions are important for proper function of splenic conventional dendritic cells. Overall design: In this approach we sorted out two populations (CD8α+ and CD8α-) of splenic dendritic cells (DCs) from untreated WT, IFN-β-/- and IFNAR-/- C57Bl/6 mice. All mice were between 8-10 weeks old. Further we isolated RNA and performed microarray analysis. Each DCs population was repeated twice.