Pharmacological inhibition of PI3K class III enhances the production of pro- and anti-inflammatory cytokines in dendritic cells stimulated by TLR agonists.
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ABSTRACT:
SUBMITTER: Pittini A
PROVIDER: S-EPMC4907315 | biostudies-literature | 2016 Jul
REPOSITORIES: biostudies-literature
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Pharmacological inhibition of PI3K class III enhances the production of pro- and anti-inflammatory cytokines in dendritic cells stimulated by TLR agonists.
Pittini Álvaro Á Casaravilla Cecilia C Allen Judith E JE Díaz Álvaro Á
International immunopharmacology 20160508
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Project description:BackgroundPlasmacytoid Dendritic Cells (pDC) comprise approximately 0.2 to 0.8% of the blood mononuclear cells and are the primary type 1 interferon (IFN), producing cells, secreting high levels of IFN in response to viral infections. Plasmacytoid dendritic cells express predominantly TLRs 7 & 9, making them responsive to ssRNA and CpG DNA. The objective of this study was to evaluate the molecular and cellular processes altered upon stimulation of pDC with synthetic TLR 7 and TLR 7/8 agonists. To this end, we evaluated changes in global gene expression upon stimulation of 99.9% pure human pDC with the TLR7 selective agonists 3M-852A, and the TLR7/8 agonist 3M-011.ResultsGlobal gene expression was evaluated using the Affymetrix U133A GeneChip(R) and selected genes were confirmed using real time TaqMan(R) RTPCR. The gene expression profiles of the two agonists were similar indicating that changes in gene expression were solely due to stimulation through TLR7. Type 1 interferons were among the highest induced genes and included IFNB and multiple IFNalpha subtypes, IFNalpha2, alpha5, alpha6, alpha8, alpha1/13, alpha10, alpha14, alpha16, alpha17, alpha21. A large number of chemokines and co-stimulatory molecules as well as the chemokine receptor CCR7 were increased in expression indicating maturation and change in the migratory ability of pDC. Induction of an antiviral state was shown by the expression of several IFN-inducible genes with known anti-viral activity. Further analysis of the data using the pathway analysis tool MetaCore gave insight into molecular and cellular processes impacted. The analysis revealed transcription networks that show increased expression of signaling components in TLR7 and TLR3 pathways, and the cytosolic anti-viral pathway regulated by RIG1 and MDA5, suggestive of optimization of an antiviral state targeted towards RNA viruses. The analysis also revealed increased expression of a network of genes important for protein ISGylation as well as an anti-apoptotic and pro-survival gene expression program.ConclusionThus this study demonstrates that as early as 4 hr post stimulation, synthetic TLR7 agonists induce a complex transcription network responsible for activating pDC for innate anti-viral immune responses with optimized responses towards RNA viruses, increased co-stimulatory capacity, and increased survival.
| S-EPMC2175514 | biostudies-literature
Project description:Toll like receptors (TLRs) sense microbial products and initiate adaptive immune responses by activating dendritic cells (DCs). Since pathogens may contain several agonists we asked whether different TLRs may synergize in DC activation. We report that in human and mouse DC TLR3 or TLR4 potently synergize with TLR7, TLR8 or TLR9 in the induction of selected cytokine genes. Upon synergistic stimulation, IL-12, IL-23 and Delta-4 are induced at levels 50-100 fold higher than those induced by optimal concentrations of single agonists, leading to enhanced and sustained TH1 polarizing capacity. Using microarray analysis we show that only 1.5% of the transcripts induced by single TLR agonists are synergistically regulated by combinations of TLR4 and TLR8 agonists.. These results identify a combinatorial code by which DCs discriminate pathogens and provide (suggest) a rationale to design adjuvants for TH1 responses. Series_overall_design: 3 untreated, 3 treated with LPS at 2h, 3 treated with LPS at 8h, 3 treated with R848 at 2h, 3 treated with R848 at 8h, 3 treated with LPS + R848 at 2h, 3 treated with LPS + R848 at 8h Keywords: other
2005-09-01 | GSE2706 | GEO
Project description:Peptide loading of MHC class II (MHCII) molecules is catalyzed by the nonclassical MHCII-related molecule H2-M. H2-O, another MHCII-like molecule, associates with H2-M and modulates H2-M function. The MHCII presentation pathway is tightly regulated in dendritic cells (DCs), yet how the key modulators of MHCII presentation, H2-M and H2-O, are affected in different DC subsets in response to maturation is unknown. In this study, we show that H2-O is markedly downregulated in vivo in mouse CD8?(-) DCs in response to a broad array of TLR agonists. In contrast, CD8?(+) DCs only modestly downregulated H2-O in response to TLR agonists. H2-M levels were slightly downmodulated in both CD8?(-) and CD8?(+) DCs. As a consequence, H2-M/H2-O ratios significantly increased for CD8?(-) but not for CD8?(+) DCs. The TLR-mediated downregulation was DC specific, as B cells did not show significant H2-O and H2-M downregulation. TLR4 signaling was required to mediate DC H2-O downregulation in response to LPS. Finally, our studies showed that the mechanism of H2-O downregulation was likely due to direct protein degradation of H2-O as well as downregulation of H2-O mRNA levels. The differential H2-O and H2-M modulation after DC maturation supports the proposed roles of CD8?(-) DCs in initiating CD4-restricted immune responses by optimal MHCII presentation and of CD8?(+) DCs in promoting immune tolerance via presentation of low levels of MHCII-peptide.
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Project description:HMGB1 has been identified as a pro-inflammatory mediator which leads to sepsis lethality. Previous studies suggested that CRISPLD2 had anti-inflammatory property and might severe as a therapeutic agent in sepsis. In the present study, we first conducted bioinformatic analysis to explore the expression profile of HMGB1 in septic survivors and non-survivors. We found that the serum HMGB1 level of septic non-survivors was significantly higher than that of septic survivors, and there was a positive correlation between CRISPLD2 and HMGB1 in mRNA expression in most of the cancer and normal tissue types, revealing a co-expression or dependency relationship between the two genes. In vitro, using cultured THP-1 cells, we confirmed that HMGB1 can induce the expression of CRISPLD2 in a time dependent manner through TLR4-dependent pathway. Given that CRISPLD2 and HMGB1 shared a wide range of time scales in gene expression and the anti-inflammatory property of CRISPLD2, we further verified that HMGB1 induced cytokines production might be partially reversed by CRISPLD2. In vivo, intravenously treatment of CRISPLD2 failed to rescue septic mice, although the serum levels of inflammatory cytokines were decreased. In conclusion, our study demonstrated that HMGB1 can act as stimuli to up-regulate the expression of CRISPLD2 in THP-1 cells, and in turn, increased CRISPLD2 can curtail HMGB1 induced pro-inflammatory cytokines production. Unfortunately, the anti-inflammatory effects of CRISPLD2 did not translate into survival benefit in mice with sepsis.
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Project description:Comparison of libraries derived from primary human bronchial epithelial cells which are [i] unstimulated, [ii] stimulated with the pro-inflammatory cytokines IL1beta and TNFalpha and [iii] stimulated with heat-inactivated Pseudomonas aeruginosa (strain PAO1). Keywords: other
2005-02-02 | E-GEOD-2056 | biostudies-arrayexpress
Project description:Heparanase is a β-D-endoglucuronidase that cleaves heparan sulfate (HS), facilitating degradation of the extracellular matrix (ECM) and the release of HS-bound biomolecules including cytokines. The remodeling of the ECM by heparanase is important for various physiological and pathological processes, including inflammation, wound healing, tumour angiogenesis and metastasis. Although heparanase has been proposed to facilitate leukocyte migration through degradation of the ECM, its role in inflammation by regulating the expression and release of cytokines has not been fully defined. In this study, the role of heparanase in regulating the expression and release of cytokines from human and murine immune cells was examined. Human peripheral blood mononuclear cells treated ex vivo with heparanase resulted in the release of a range of pro-inflammatory cytokines including IL-1β, IL-6, IL-8, IL-10 and TNF. In addition, mouse splenocytes treated ex vivo with heparanase resulted in the release of IL-6, MCP-1 and TNF. A similar pattern of cytokine release was also observed when cells were treated with soluble HS. Furthermore, heparanase-induced cytokine release was abolished by enzymatic-inhibitors of heparanase, suggesting this process is mediated via the enzymatic release of cell surface HS fragments. As soluble HS can signal through the Toll-like receptor (TLR) pathway, heparanase may promote the upregulation of cytokines through the generation of heparanase-cleaved fragments of HS. In support of this hypothesis, mouse spleen cells lacking the key TLR adaptor molecule MyD88 demonstrated an abolition of cytokine release after heparanase stimulation. Furthermore, TLR4-deficient spleen cells showed reduced cytokine release in response to heparanase treatment, suggesting that TLR4 is involved in this response. Consistent with these observations, the pathway involved in cytokine upregulation was identified as being NF-κB-dependent. These data identify a new mechanism for heparanase in promoting the release of pro-inflammatory cytokines that is likely to be important in regulating cell migration and inflammation.
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Project description:Comparison of libraries derived from primary human bronchial epithelial cells which are [i] unstimulated, [ii] stimulated with the pro-inflammatory cytokines IL1beta and TNFalpha and [iii] stimulated with heat-inactivated Pseudomonas aeruginosa (strain PAO1). Keywords: other
2005-02-03 | GSE2056 | GEO
Project description:There is mounting evidence that galectin-3 is a prognostic and diagnostic biomarker associated with diverse diseases and conditions, including cancer, cardiovascular disease, autoimmunity, wound healing, allergic disease, and chronic inflammation in general. Yet, whether and exactly how galectin-3 may participate in the pathogenesis of these diseases remains poorly understood. Recently, we have linked the expression of galectin-3 on the A549 epithelial cell line -an adenocarcinoma, to the activation of human basophils for the release of histamine and secretion of IL-4 and IL-13. These responses proved dependent on cell-to-cell contact, basophil expression of IgE, were inhibited by n-acetyllactosamine, and were ablated when basophils were co-cultured with A549 clones lacking galectin-3 expression. While recombinant galectin-3 failed to activate basophils when in solution, microspheres expressing this lectin did so by mimicking the responses seen when using A549 cells. Given the IgE dependency of the basophil responses, and the fact that galectin-3 is long known to bind this immunoglobulin, we hypothesize that a similar mode of activation extends to other IgE-bearing cells. To investigate this possibility, we tested epithelial cell-associated galectin-3 for its capacity to activate human dendritic cells, including the plasmacytoid and myeloid subtypes as well as monocytes, all of which bind IgE. Indeed, results indicate that epithelial cell-associated galectin-3 activated these cells for robust production of TNF-α and IL-6 and up-regulated the expression of activation markers found on dendritic cells. Moreover, many of the same parameters previously observed for basophils applied to the findings herein, including evidence that matrix-bound galectin-3 (whether on epithelial cells or microspheres) facilitates this mode of activation. In contrast, IgE expression was dispensable for these galectin-3-dependent cytokine responses, implying that this lectin activates dendritic cells (and monocytes) by binding to a glycoprotein other than this immunoglobulin. Overall, these findings further demonstrate how galectin-3 mediates immune cell activation, providing novel insight into how this lectin may promote chronic inflammation underlying the pathogenesis of many diseases.
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Project description:On the basis of studies in mouse macrophages, activation of the nucleotide-binding oligomerization domain-like receptor (NLR) pyrin domain-containing 3 (Nlrp3) inflammasome is thought to require two signals. The first signal is provided by TLR stimulation and triggers the synthesis of the IL-1β precursor and Nlrp3. The second signal can be mediated by stimulation of the purinergic receptor P2X ligand-gated ion channel 7 (P2X7) by millimolar concentrations of ATP. However, these high concentrations of ATP are not found normally in the in vivo extracellular milieu, raising concern about the physiological relevance of the ATP-P2X7 pathway of inflammasome activation. In this article, we show that unlike macrophages, murine bone marrow-derived and splenic dendritic cells (DCs) can secrete substantial amounts of mature IL-1β upon stimulation with TLR ligands in the absence of ATP stimulation. The differential ability of DCs to release IL-1β and activate caspase-1 was associated with increased expression of Nlrp3 under steady-state conditions and of pro-IL-1β and Nlrp3 after stimulation with TLR agonists. IL-1β secretion from stimulated DCs was largely dependent on the Nlrp3 inflammasome, but independent of P2X7 and unaffected by incubation with apyrase. More importantly, i.p. administration of LPS induced IL-1β production in serum, which was abrogated in Nlrp3-null mice but was unaffected in P2X7-deficient mice. These results demonstrate differential regulation of the Nlrp3 inflammasome in macrophages and DCs. Furthermore, they challenge the idea that the ATP-P2X7 axis is critical for TLR-induced IL-1β production via the Nlrp3 inflammasome in vivo.
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Project description:Various TLR agonists are currently under investigation in clinical trials for their ability to orchestrate antitumor immunity. The antitumor responses are largely attributed to their aptitude to stimulate APCs such as DCs which in turn, activate tumor-specific T cell responses. However, there is a potential for TLR signaling to occur on cells other than professional APCs that could negate antitumor responses or even worse, promote tumor growth. The impetus for this review is twofold. First, there is accumulating data demonstrating that the engagement of TLRs on different T cell subsets and different cancer types could promote tumor growth or conversely, contribute to antitumor responses. Second, the efficacy of TLR agonists as monotherapies to treat cancer patients has been limited. In this review, we discuss how TLR signaling within different T cell subsets and cancer cells can potentially impact the generation of antitumor responses. Based on evidence from preclinical models and clinical trials, we draw attention to several criteria that we believe must be considered when selecting TLR agonists for developing effective immunotherapeutic strategies against cancer.
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