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Transcriptome analysis of murine macrophages in response to infection with Streptococcus pyogenes

ABSTRACT: The complex response of murine macrophages to infection with Streptococcus pyogenes was investigated at the level of gene expression using a high-density oligomer microarray. More than 400 genes were identified as being differentially regulated. Many of the up-regulated genes encoded molecules were involved in immune response and inflammation, transcription, signalling, apoptosis, cell cycle, electron transport and cell adhesion. Of particular interest was the up-regulation of proinflammatory cytokines, typical of the classically activated macrophages (M1 phenotype) such as TNF-?, IL-1 and IL-6, and also the up-regulation of anti-inflammatory mediators such as IL-1ra and IL-10 associated with macrophage alternative activation (M2 phenotype). Furthermore, the gene encoding inducible nitric oxide synthase (iNOS), an enzyme typically implicated in classical activation was not induced in infected macrophages. Instead, the gene encoding arginase, a competitor for the iNOS substrate arginine and involved in the alternative activation pathway was up-regulated in S. pyogenes-infected cells. Thus, the microarray-based gene expression analysis demonstrated that S. pyogenes induced an atypical activation program in macrophages with some but not all features of classically or alternatively activation phenotypes. The microarray data also suggested that the bactericidal activity of macrophages against S. pyogenes is mediated by phagocyte oxydase since p47phox was up-regulated in infected cells. Indeed, the in vivo and in vitro killing of S. pyogenes was markedly diminished in the absence of functional phagocyte (p47phox-/-) but not in the absence of iNOS (iNOS-/-). Understanding how macrophages respond to S. pyogenes at the molecular level may facilitate the development of new therapeutic paradigms. Keywords: infection response

ORGANISM(S): Mus musculus

PROVIDER: GSE7769 | GEO | 2008/03/14

SECONDARY ACCESSION(S): PRJNA99787

REPOSITORIES: GEO

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Project description:The complex response of murine macrophages to infection with Streptococcus pyogenes was investigated at the level of gene expression using a high-density oligomer microarray. More than 400 genes were identified as being differentially regulated. Many of the up-regulated genes encoded molecules were involved in immune response and inflammation, transcription, signalling, apoptosis, cell cycle, electron transport and cell adhesion. Of particular interest was the up-regulation of proinflammatory cytokines, typical of the classically activated macrophages (M1 phenotype) such as TNF-?, IL-1 and IL-6, and also the up-regulation of anti-inflammatory mediators such as IL-1ra and IL-10 associated with macrophage alternative activation (M2 phenotype). Furthermore, the gene encoding inducible nitric oxide synthase (iNOS), an enzyme typically implicated in classical activation was not induced in infected macrophages. Instead, the gene encoding arginase, a competitor for the iNOS substrate arginine and involved in the alternative activation pathway was up-regulated in S. pyogenes-infected cells. Thus, the microarray-based gene expression analysis demonstrated that S. pyogenes induced an atypical activation program in macrophages with some but not all features of classically or alternatively activation phenotypes. The microarray data also suggested that the bactericidal activity of macrophages against S. pyogenes is mediated by phagocyte oxydase since p47phox was up-regulated in infected cells. Indeed, the in vivo and in vitro killing of S. pyogenes was markedly diminished in the absence of functional phagocyte (p47phox-/-) but not in the absence of iNOS (iNOS-/-). Understanding how macrophages respond to S. pyogenes at the molecular level may facilitate the development of new therapeutic paradigms. Experiment Overall Design: Total RNA was isolated from highly purified F4/80+ cells obtained from the peritoneal cavity of C3H/HeN infected and uninfected control mice and hybridized to an Affymetrix GeneChip MOE430A.

Project description:Effects of the matricellular protein CCN1 on macrophage inflammatory gene expression was tested in a macrophage cell line I-13.35. CCN1 (CYR61) is a matricellular protein that is highly expressed at sites of inflammation and wound repair. In these contexts, CCN1 can modify the activities of specific cytokines, enabling TNF-alpha to be cytotoxic without blocking NFkB activity and enhancing the apoptotic activity of FasL and TRAIL. Here we show that CCN1 supports the adhesion of macrophages through integrin alphaMbeta2 and syndecan-4, activates NFkB-mediated transcription, and induces a pro-inflammatory genetic program characteristic of classically activated M1 macrophages that participates in Th1 responses. The effects of CCN1 include upregulation of cytokines (TNFa, IL-1a, IL-1b, IL-6, IL-12b), chemokines (MIP-1a, MCP-3, Gro1, Gro2, IP-10), regulators of oxidative stress and complement (iNOS, C3), and downregulation of specific receptors (TLR4, IL-10rb) and anti-inflammatory factors (TGF-b1). CCN1 regulates this genetic program through at least two distinct mechanisms: an immediate-early response resulting from direct activation of NFkB by CCN1, leading to the synthesis of cytokines including TNFa and IP-10; and a delayed response resulting from CCN1-induced TNFa, which acts as an autocrine/paracrine mediator to activate the expression of other cytokines including IL-1b and IL-6. These results identify CCN1 as a novel component of the extracellular matrix that activates pro-inflammatory genes in macrophages, implicating its role in regulating macrophage function during inflammation. Macrophage cell line I-13.35 (from Tlr4-defective C3H/HeJ) was treated with purified recombinant CCN1 protein for 6 hr. Total RNA was isolated, converted to cRNA probes, and hybridized to a oligonucleotide array representing 113 murine inflammation-related genes (from SA Biosciences at www.sabiosciences.com, Cat. Number OMM-011.) The array is a nylon membrane based DNA microarray on which 60-mer oligonucleotides probes were printed. Gene expression profile of resting cells incubated in serum-free medium (containing albumin, BSA) was used as a control for basal levels of gene expression.

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.

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Transcriptome analysis of murine macrophages in response to infection with Streptococcus pyogenes

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