Project description:Here we investigate how glucocorticoids affect the response to Interferon gamma in human macrophages. Total RNA obtained from monocyte-derived macrophages exposed to Interferon gamma presceding exposure to fluticasone propionate or left untreated.
Project description:Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, a bacterium that mainly infects endothelial cells in vitro and in vivo. Evidence suggests that the interaction of O. tsutsugamushi with myeloid cells may play a pivotal role in O. tsutsugamushi infection. We showed here that O. tsutsugamushi intensively replicated within human monocyte-derived macrophages. Bacterial organisms stimulated the expression of a large panel of genes including type I interferon, interferon-stimulated, inflammatory, apoptosis-related genes and induced an M1-type gene response in macrophages. This transcriptional signature was accompanied by functional consequences such as the release of inflammatory cytokines such as Tumor Necrosis Factor and interleukin-gamma. Live O. tsutsugamushi organisms were necessary for type I interferon response and, to a lesser degree, to inflammatory response. As interferon-gamma is known to elicit M1 polarization, we assessed the effect of interferon-gamma on O. tsutsugamushi fate in macrophages. Exogenous interferon-gamma partly inhibited O. tsutsugamushi replication within macrophages. Our results suggest that the inflammatory response induced by O. tsutsugamushi may account for the local and systemic inflammation observed in scrub typhus and that interferon-gamma may be useful as an adjuvant treatment of patients with scrub typhus. Macrophages (4 M-CM-^W 10.5 cells per assay) were incubated with O. tsutsugamushi at a bacterium-to-cell ratio of 20:1 for 8 hours. RNA samples (four samples per experimental condition) were processed for microarray analysis.
Project description:Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, a bacterium that mainly infects endothelial cells in vitro and in vivo. Evidence suggests that the interaction of O. tsutsugamushi with myeloid cells may play a pivotal role in O. tsutsugamushi infection. We showed here that O. tsutsugamushi intensively replicated within human monocyte-derived macrophages. Bacterial organisms stimulated the expression of a large panel of genes including type I interferon, interferon-stimulated, inflammatory, apoptosis-related genes and induced an M1-type gene response in macrophages. This transcriptional signature was accompanied by functional consequences such as the release of inflammatory cytokines such as Tumor Necrosis Factor and interleukin-gamma. Live O. tsutsugamushi organisms were necessary for type I interferon response and, to a lesser degree, to inflammatory response. As interferon-gamma is known to elicit M1 polarization, we assessed the effect of interferon-gamma on O. tsutsugamushi fate in macrophages. Exogenous interferon-gamma partly inhibited O. tsutsugamushi replication within macrophages. Our results suggest that the inflammatory response induced by O. tsutsugamushi may account for the local and systemic inflammation observed in scrub typhus and that interferon-gamma may be useful as an adjuvant treatment of patients with scrub typhus.
Project description:Glucocorticoids are extensively used to treat inflammatory diseases, however their chronic intake increases the risk of mycobacterial infections. Meanwhile, the effects of glucocorticoids on innate host responses are incompletely understood. Here, we studied the direct effects of glucocorticoids on antimycobacterial host defense in primary human macrophages. We found that glucocorticoids triggered the expression of cathelicidin, an antimicrobial critical for antimycobacterial response, independent of the intracellular vitamin D metabolism. Despite upregulating cathelicidin, glucocorticoids failed to promote macrophage antimycobacterial activity. Gene expression profiles of human macrophages treated with glucocorticoids and/or IFN-gamma, which promotes induction of cathelicidin, as well as antimycobacterial activity, were investigated. Using weighted gene coexpression network analysis (WGCNA), we identified a module of highly connected genes that was strongly inversely correlated with glucocorticoid treatment and associated with IFN-gamma stimulation. This module was linked to the biological functions âautophagyâ, âphagosome maturationâ and âlytic vacuole/lysosomeâ, and contained the vacuolar H+-ATPase (v-ATPase) subunit a3, alias TCIRG1, a known antimycobacterial host defense gene, as a top hub gene. We next found that glucocorticoids, in contrast to IFN-gamma, failed to trigger expression and phagolysosome recruitment of TCIRG1, as well as to promote lysosome acidification. Finally, we demonstrated that the tyrosine kinase inhibitor imatinib induces lysosome acidification and antimicrobial activity in glucocorticoid-treated macrophages without reversing the anti-inflammatory effects of glucocorticoids. Taken together, we provide evidence that the induction of cathelicidin by glucocorticoids is not sufficient for macrophage antimicrobial activity, and identify the v-ATPase as a potential target for host-directed therapy in the context of glucocorticoid therapy. Peripheral blood mononuclear cells (PBMCs) of three healthy human donors were isolated by Ficoll-Paque (GE Healthcare). Monocytes were isolated via CD14+ MACS cell separation (Miltenyi Biotec) according to the manufacturers instructions. Monocyte-derived macrophages (MDMs) were prepared by culturing peripheral blood monocytes in RPMI media containing 10% FCS for four to seven days in the presence of M-CSF (50 ng/ml). Afterwards cells were cultured in fresh media with 10% vitamin D-sufficient human AB serum. Cells were stimulated with media, dexamethasone, interferon-gamma and dexamethasone/interferon-gamma for 20h. Total RNA of was isolated with TRIZOL (Life Technologies) and RNA quality was confirmed using micro capillary electrophoresis (2100 Bioanalyzer, Agilent). 100ng RNA was labeled and hybridized to Sureprint G3 human GE 8x60K whole genome mRNA microarray according to the manufacturerâs specifications. The arrays were scanned (Agilent G2595C scanner), data extracted and processed using the Genespring XII software (Agilent).
Project description:Macrophages are known to be polarized into inflammatory (M1) and immunoregulatory (M2) cells when they are stimulated by agonists such as IFN-gamma and IL-4, respectively. If circulating monocytes may be polarized in response to T cell signals is often misguidedly deduced from macrophage results. Here the transcriptional responses of human CD14+ monocytes to IFN-gamma and IL-4 were analyzed using whole genome microarrays. A principal component analysis and hierarchical clustering showed that monocyte and macrophage responses were distinct. Monocytes stimulated with IFN-gamma and IL-4 for 6 hours exhibited some features of macrophage polarization. Indeed, when 80 genes considered as M1 and M2 genes were analyzed, we found that M1 genes were modulated in response to IFN-gamma and that M2 genes were modulated in response to IL-4. The M1 polarization of monocytes was transient because only M2 genes were modulated when monocytes were stimulated with IFN-gamma and IL-4 for 18 hours. However, the activation of monocytes by IFN-gamma and IL-4 could not be reduced to M1/M2 polarization status. Indeed, monocytes exhibited early specific signatures composed of 46 and 39 up-regulated genes in response to IFN-gamma and IL-4, respectively, and a late signature common to both molecules that consisted of 57 up-regulated genes. Taken together, these results demonstrated the extreme plasticity of human monocytes and suggested the existence of a core transcriptional termination program. Using early and late signatures might be pertinent to investigate monocyte activation in inflammatory or infectious diseases. Monocytes were stimulated with IFN-gamma (20ng/mL) or IL-4 (20ng/mL) for 6 and 18 hours or culture for 6 and 18 hours without agonist (Unstimulated samples). Monocytes-derived-macrophages (MDM) stimulated with IFN-gamma and IL-4 for 18 hours were used as controls. Each microarray is derived from a single biological sample.
Project description:Transcriptome profiles for innate and adaptive immune stimuli important for host response against mycobacteria. Human monocyte-derived macrophages were stimulated with TLR2/1 ligand and interferon-g, stimuli present during innate and adaptive immune responses, respectively.