Project description:Ocular immune privilege (IP) limits immune surveillance of intraocular tumors as certain immunogenic tumor cell lines (P815, E.G7-OVA) that are rejected when transplanted in the skin grow progressively when placed in the anterior chamber (a.c.) of the eye. As splenectomy (SPLNX) is known to terminate ocular IP, we characterized immune mechanisms responsible for spontaneous rejection of intraocular tumors in SPLNX mice as a first step toward identifying how to restore tumoricidal activity within the eye. Microarray data showed a 3-fold increase in interferon (IFN)-γ and a 2.7-fold increase in Fas ligand (FasL). There was a robust increase in transcripts (127 of 408 surveyed) from interferon (IFN)-stimulated genes and a marked decrease (in 40 of 192 surveyed) in the expression of cell-cycle-associated genes. Non-microarray data confirmed that IFNγ, FasL and CD8+ T cells but not perforin or TNFα were required for elimination of intraocular E.G7-OVA tumors that culminated in destruction of the eye (ocular phthsis). IFNγ and FasL did not target tumor cells directly as the majority of SPLNX IFNγR1-/- mice and Fas-defective lpr mice failed to eliminate ocular E.G7-OVA tumors that expressed Fas and IFNγR1. Bone marrow chimeras showed that immune cell expression of IFNγR1 and Fas was critical and that SPLNX increased the frequency of activated macrophages within ocular tumors in an IFNγ- and Fas/FasL-dependent manner. Rejection of intraocular tumors was associated with increased ocular mRNA expression of several inflammatory genes including FasL, NOS2, CXCL2 and T-bet. Our data support a model in which IFNγ- and Fas/FasL-dependent activation of intratumoral macrophage by CD8+ T cells promotes severe intraocular inflammation that indirectly eliminates intraocular tumors by inducing phthisis. The immunosuppressive mechanisms which maintain ocular IP likely interfere with the interaction between CD8+ T cells and macrophage to limit immunosurveillance of intraocular tumors. C57BL/6 mice that were splenectomized (Tumor_splnx) or were not surgically manipulated (Tumor_intact) were challenged with 10^4 luciferase-expressing E.G7-OVA cells injected into the anterior chamber of the eye. Fifteen days later, the animals were euthanized and tumor-bearing eyes were removed.
Project description:Ocular immune privilege (IP) limits immune surveillance of intraocular tumors as certain immunogenic tumor cell lines (P815, E.G7-OVA) that are rejected when transplanted in the skin grow progressively when placed in the anterior chamber (a.c.) of the eye. As splenectomy (SPLNX) is known to terminate ocular IP, we characterized immune mechanisms responsible for spontaneous rejection of intraocular tumors in SPLNX mice as a first step toward identifying how to restore tumoricidal activity within the eye. Microarray data showed a 3-fold increase in interferon (IFN)-γ and a 2.7-fold increase in Fas ligand (FasL). There was a robust increase in transcripts (127 of 408 surveyed) from interferon (IFN)-stimulated genes and a marked decrease (in 40 of 192 surveyed) in the expression of cell-cycle-associated genes. Non-microarray data confirmed that IFNγ, FasL and CD8+ T cells but not perforin or TNFα were required for elimination of intraocular E.G7-OVA tumors that culminated in destruction of the eye (ocular phthsis). IFNγ and FasL did not target tumor cells directly as the majority of SPLNX IFNγR1-/- mice and Fas-defective lpr mice failed to eliminate ocular E.G7-OVA tumors that expressed Fas and IFNγR1. Bone marrow chimeras showed that immune cell expression of IFNγR1 and Fas was critical and that SPLNX increased the frequency of activated macrophages within ocular tumors in an IFNγ- and Fas/FasL-dependent manner. Rejection of intraocular tumors was associated with increased ocular mRNA expression of several inflammatory genes including FasL, NOS2, CXCL2 and T-bet. Our data support a model in which IFNγ- and Fas/FasL-dependent activation of intratumoral macrophage by CD8+ T cells promotes severe intraocular inflammation that indirectly eliminates intraocular tumors by inducing phthisis. The immunosuppressive mechanisms which maintain ocular IP likely interfere with the interaction between CD8+ T cells and macrophage to limit immunosurveillance of intraocular tumors.
Project description:Interferon (IFN)γ and interleukin (IL)-4 are central regulators of T helper 1 (Th1) and T helper 2 (Th2) immune responses, respectively. Both cytokines have a major impact on macrophage phenotypes: IFNγ–priming and subsequent TLR4 activation induces so called classically activated macrophages that are characterized by pronounced pro-inflammatory responses, whereas IL-4–treated macrophages, commonly called alternatively activated, are known to develop enhanced capacity for endocytosis, antigen presentation, and tissue repair and are generally considered anti-inflammatory. Considering IL-4 as priming rather than activating stimulus, we now compared the TLR4–dependent global gene activation program in IFNγ– versus IL-4–pretreated mouse macrophages, which has rarely been studied so far. Although both cytokines frequently induced opposing effects on gene transcription, the subsequent activation of bone marrow-derived macrophages by lipopolysaccharide (LPS) produced a strong, priming dependent pro-inflammatory response in both macrophage types. For example, the production of key pro-inflammatory cytokines IL-6 and IL-12 was significantly higher in IL-4– versus IFNγ–primed macrophages and several cytokine genes, including Il19, Ccl17, Ccl22, Ccl24 and Cxcl5, were preferentially induced in alternatively primed and LPS activated mouse macrophages. In a subset of genes, including IL12a, IFNγ priming was actually found to suppress LPS–induced gene expression in a Stat1–dependent manner. Our data suggest that IL-4–priming is not per se anti-inflammatory but generates a macrophage that is “tissue protective” but still capable of mounting a strong inflammatory response after TLR4–dependent activation. Keywords: Gene expression profiling Gene expression was investigated in mouse bone marrow-derived macrophages (BMM). On day 7, BMM were stimulated with either IL-4 or IFNγ overnight (18h in total). LPS treatment was performed in primed and unprimed macrophages 4 h prior to harvesting. At least three independent experiments were performed for each condition.
Project description:SP110b is an interferon (IFN)-induced nuclear protein and may function as a transcriptional co-activator/repressor. IFNγ activates monocytes/macrophages thereby mediating inflammation. However, uncontrolled activation induces monocyte/macrophage cell death, which may cause immunopathology. We have demonstrated that SP110b expression prevented IFNγ-mediated monocyte/macrophage cell death. To explore the molecular mechanisms by which SP110b suppresses IFNγ-induced cell death, we performed a genome-wide microarray analysis to identify genetic determinants associated with IFNγ-induced cell death and regulated by SP110b. We sought to identify genetic determinants associated with IFNγ-induced cell death and regulated by SP110b. To that end, THP1 human monocyte-like cells that could be induced by doxycycline (Dox) to over-express SP110b (THP1-SP110b) were generated and 5 experimental groups of THP1-SP110b cells were harvested for RNA extraction and hybridization on Affymetrix microarrays. The 5 groups are as follows: untreated THP1-SP110b cells as control (CON), cells treated with IFNγ for 2 days (IFN_2D), cells treated with Dox plus IFNγ for 2 days (DoxIFN_2D), cells treated with IFNγ for 4 days (IFN_4D), and cells treated with Dox plus IFNγ for 4 days (DoxIFN_4D).
Project description:Changes in the nuclear positioning of specific genes, depending on their expression status, have been observed in a large diversity of physiological processes. However, gene position is poorly documented in immune cells subjected to activation upon bacterial infection. Using the pig as a model organism, we focused our study on monocytes-derived macrophages and neutrophils, the first lines of defense against pathogens. We examine whether changes in gene expression due to LPS-activation imply genes repositioning in the nuclear space. A transcriptomic analysis was first performed to identify the genes differentially expressed and analyse the networks implicated during LPS-IFNγ activation in monocytes-derived macrophages. This allowed us to select 4 up-regulated (IL1β, IL8, CXCL10 and TNFα) and 4 down-regulated (VIM, LGALS3, TUBA3, and IGF2) genes to be further studied by 3D-FISH for their behavior in the nuclear space, particularly towards their chromosome territories (CT) during macrophages activation. Among the 4 up-regulated genes, 3 changed their position during the activation process while the 4 down-regulated ones did not. The analysis of gene behaviors towards their CT was extended to neutrophils for 3 up- and 2 down-regulated genes and similar results were obtained. Our data suggest that relocation in the nuclear space of genes differentially expressed in activated immune cells is gene specific and concern mostly up-regulated ones. Porcine monocyte-derived macrophages: Control vs. LPS-IFNγ activated vs. T-2 toxin/LPS-IFNγ activated. A common reference hybridization scheme was used to compare the three-condition experiment, CM vs. AM vs. TAM. The reference consisted of a pool of RNA from all samples. Biological replicates: 5 control, 5 LPS-IFNγ activated, 5 T-2 toxin/LPS-IFNγ activated independently. One replicate per array.
Project description:Altered lipid metabolism in macrophages is associated with various important inflammatory conditions. Although lipid metabolism is an important target for therapeutic intervention, the metabolic requirement involved in lipid accumulation during pro-inflammatory activation of macrophages remains incompletely characterized. We show here that macrophage activation with IFNγ results in increased aerobic glycolysis, iNOS-dependent inhibition of respiration, and accumulation of triacylglycerol. Surprisingly, metabolite tracing with 13C-labeled glucose revealed that the glucose contributed to the glycerol groups in triacylglycerol (TAG), rather than to de novo synthesis of fatty acids. This is in stark contrast to the otherwise similar metabolism of cancer cells, and previous results obtained in activated macrophages and dendritic cells. Our results establish a novel metabolic pathway whereby glucose provides glycerol to the headgroup of TAG during classical macrophage activation.
Project description:The cytokine IFNγ differentially impacts on tumors upon immune checkpoint blockade (ICB). Despite our understanding of downstream signaling events, less is known about 36 regulation of its receptor (IFNγ-R1). With an unbiased genome-wide CRISPR/Cas9 screen for critical regulators of IFNγ-R1 cell surface abundance, we identified STUB1 as an E3 ubiquitin ligase for IFNγ-R1 in complex with its signal-relaying kinase JAK1. STUB1 mediates ubiquitination-dependent proteasomal degradation of IFNγ-R1/JAK1 complex through IFNγ-R1K285 and JAK1K249. Conversely, STUB1 inactivation amplifies IFNγ signaling, sensitizing tumor cells to cytotoxic T cells in vitro. This was corroborated by an anticorrelation between STUB1 expression and IFNγ response in ICB-treated patients. Consistent with the context-dependent effects of IFNγ in vivo, anti-PD-1 response was increased in heterogenous tumors comprising both wildtype and STUB1-deficient cells but not full STUB1 knockout tumors. These results uncover STUB1 as a critical regulator of IFNγ-R1, and highlight the context-dependency of STUB1-regulated IFNγ signaling for ICB outcome.
Project description:Interferon (IFN)γ and interleukin (IL)-4 are central regulators of T helper 1 (Th1) and T helper 2 (Th2) immune responses, respectively. Both cytokines have a major impact on macrophage phenotypes: IFNγ–priming and subsequent TLR4 activation induces so called classically activated macrophages that are characterized by pronounced pro-inflammatory responses, whereas IL-4–treated macrophages, commonly called alternatively activated, are known to develop enhanced capacity for endocytosis, antigen presentation, and tissue repair and are generally considered anti-inflammatory. Considering IL-4 as priming rather than activating stimulus, we now compared the TLR4–dependent global gene activation program in IFNγ– versus IL-4–pretreated mouse macrophages, which has rarely been studied so far. Although both cytokines frequently induced opposing effects on gene transcription, the subsequent activation of bone marrow-derived macrophages by lipopolysaccharide (LPS) produced a strong, priming dependent pro-inflammatory response in both macrophage types. For example, the production of key pro-inflammatory cytokines IL-6 and IL-12 was significantly higher in IL-4– versus IFNγ–primed macrophages and several cytokine genes, including Il19, Ccl17, Ccl22, Ccl24 and Cxcl5, were preferentially induced in alternatively primed and LPS activated mouse macrophages. In a subset of genes, including IL12a, IFNγ priming was actually found to suppress LPS–induced gene expression in a Stat1–dependent manner. Our data suggest that IL-4–priming is not per se anti-inflammatory but generates a macrophage that is “tissue protective” but still capable of mounting a strong inflammatory response after TLR4–dependent activation. Keywords: Gene expression profiling
Project description:Blocking the action of the PD-1 protein in lymphocytes results in their activation leading to an effective immune response in cancers and in experimental viral infections. But such immunotherapy in clinical cases results in immune adverse effects among them the development of autoimmune diabetes. In the diabetes susceptible NOD mice, blockade of the PD-L1/PD-1 pathway during the pre-diabetic stage results in severe and acute diabetes. Single-cell RNA sequencing and flow cytometry analysis of islets following blockade of the PD-L1/PD-1 pathway identified a cascade of cellular interactions involving resident macrophages and diabetogenic T cells. Such reactions led to the recruitment of monocyte derived macrophages that caused diabetes. Elimination of the monocyte derived macrophages resulted in protection. The cytocidal activity was highly dependent on IFNγ signaling and the downstream release of nitric oxide by the monocyte derived macrophages. The activation of macrophages required both the participation of CD4 and CD8 T cells. Our studies call attention to macrophages as the major effector cell following blockade of PD-1. Targeting the monocyte-derived macrophage provides a new option to prevent and treat immune checkpoint blockade induced diabetes and perhaps other immune adverse reactions.
Project description:Many cancers recruit monocytes/macrophages and polarize them into tumor-associated macrophages (TAMs). TAMs promote tumor growth and metastasis and inhibit cytotoxic T cells, preventing immune control of the cancer. However, macrophages polarized by lipopolysaccharide (a bacteria-derived toll-like receptor 4 [TLR4] agonist) and interferon gamma (IFNγ) instead kill cancer cells. They do so via nitric oxide (NO), generated by inducible NO synthase (iNOS). Altering the polarization of macrophages might therefore be a strategy for controlling tumors. Here, we show that monophosphoryl lipid A (MPLA, a TLR4 agonist used as a vaccine adjuvant)- and IFNγ-activated human macrophages from metastatic breast cancers to kill the same patients’ cancer cells in vitro. Excitingly, intratumoral injection of MPLA with IFNγ not only controlled local tumor growth but also led to reduced metastasis in mouse models of metastatic luminal and triple negative breast cancers. Furthermore, intraperitoneal administration of MPLA and IFNγ reprogrammed peritoneal macrophages and suppressed metastasis in ID8-p53-/- ovarian tumor-bearing mice. We found that the combination of MPLA and IFNγ reprogrammed the immunosuppressive microenvironment to be immunostimulatory by recruiting leukocytes, stimulating type I interferon signaling, reprogramming tumor-associated (CD206+) macrophages to tumoricidal (iNOS+) macrophages, and activating cytotoxic T cells through macrophage-secreted IL12 and TNFα. Both macrophages and T cells, including memory T cells (CD44+CD62L-), were critical for the anti-metastatic effects of MPLA and IFNγ. MPLA and IFNγ are used individually in humans, so our strategy to engage the anti-tumor immune response, which requires no knowledge of unique tumor antigens, may be ready for near-future clinical testing.