Project description:Influenza A Virus (IAV) triggers an exuberant host response that promotes acute lung injury. However, the determinants of the pathological host response to IAV remain incompletely understood. In the current study, we identified interferon (IFN)-γ-regulated subset of monocytes, CCR2+ monocytes, as a driver of lung damage during IAV pathogenesis. IFN-γ regulated the recruitment and inflammatory phenotype of CCR2+ monocytes, and CCR2 (CCR2-/-) and IFN-γ (IFN-γ-/-) deficient mice exhibited reduced lung inflammation, pathology, and increased resistance against bacterial co-infection by Streptococcus pneumoniae (Spn). Adoptive transfer of WT (IFN-γR1+), but not IFN-γR1 deficient (IFN-γR1-) CCR2+ monocytes, restored the wild-type (WT)-like pathological phenotype of lung damage in IAV-infected CCR2-/- mice. The CD8+ T cells were the most significant source of IFN-γ in IAV-infected lungs. Collectively, our data highlight that IFN-γ regulates CCR2+ monocyte-mediated lung pathology during IAV pathogenesis.
Project description:Timecourse experiment (0hr, 2hr,6hr and 21hr) where RNA was extracted from non-rested PBMCs which were exposed to 4 different conditions- nothing (mock), interferon (IFN)gamma, IFN gamma and a non-specific antibody and IFN gamma with purified patient antibody. The purified patient antibody is demonstrated to have a specific anti-interferon gamma effect over time, with the expression profile in the arrays with IFN gamma plus patient antibody most closely resembling the mock arrays. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Keywords: disease_state_design
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:Compared to primary human monocytes in whole blood cultures, few B cells activated STAT1 in response to stimulation of 2000 IU/ml IFN-beta for 45 minutes. Because activation of STAT1 leads to apoptosis induction, we tested the hypothesis that less pro-apoptotic genes are induced in B cells as compared to monocytes. Manuscript titled: Major differences in the responses of primary human leukocyte subsets to IFN-beta. Abstract: Treatment of cell lines with type I IFNs activates the formation of ISGF3 (STAT1/STAT2/ IRF9), which induces the expression of many genes. To study this response in primary cells, we treated fresh human blood with IFN-beta and used flow cytometry to analyze phosphorylated STATs1, 3 and 5 in CD4+ and CD8+ T cells, B cells, and monocytes. The activation of STAT1 was remarkably different among these leukocyte subsets. In contrast to monocytes, CD4+ and CD8+ T cells, few B cells activated STAT1 in response to IFN-beta, a finding that could not be explained by decreased levels of IFNAR2 or STAT1 or enhanced levels of SOCS1 or relevant protein tyrosine phosphatases in B cells. Micro-array and real-time PCR analyses revealed the induction of STAT1-dependent pro-apoptotic mRNAs in monocytes but not in B cells. These data show that ISGF3 or STAT1 homodimers are not the main activators of gene expression in primary B cells of healthy humans. Notably, in B cells and especially in CD4+ T cells, IFN-beta activated STAT5 in addition to STAT3, with biological effects often opposite from those driven by activated STAT1. These data help to explain why IFN-beta increases the survival of primary human B cells and CD4+ T cells, but enhances the apoptosis of monocytes, and also to understand how leukocyte subsets are differentially affected by endogenous type I IFNs during viral or bacterial infections, and by type I IFN treatment of patients with multiple sclerosis, hepatitis or cancer. Undiluted whole blood of 2 healthy individuals (HI) was used, and either stimulated with IFN-beta or left untreated (control) for 3 hrs. After 3 hrs, both B cells and monocytes were isolated from whole blood of the first healthy individual, and only B cells were isolated from whole blood of the second healthy individual.
Project description:T-cell activation is a key feature of chronic HIV infection and is predictive of non-AIDS-defining comorbidities in people with HIV (PWH) receiving antiretroviral therapy (ART). Monocytes from PWH display distinct transcriptional programs, yet their role in T-cell activation remains unclear. In this study, we investigated how the response of CD14⁺ monocytes from PWH to type I interferon (IFN-1) influences T-cell activation. Ex vivo transcriptional profiles and in vitro IFN-1 responses of CD14⁺ monocytes were compared between PWH and uninfected individuals (UI). We identified distinct ex vivo transcriptional signatures in CD14⁺ monocytes from PWH versus UI, as well as differential responses to IFN-1. T cells from ART-treated PWH exhibited persistent activation, which correlated positively with IFN-1-stimulated gene expression. In vitro IFN-1 exposure led to increased proportions of activated CD4⁺ T cells in PWH—but not in UI—an effect reproduced by the transfer of IFN-1-primed CD14⁺ monocytes. Finally, JAK inhibitors effectively blocked IFN-1-mediated T-cell activation. Our findings underscore the role of IFN-1-primed CD14⁺ monocytes in sustaining chronic T-cell activation during HIV infection and highlight JAK inhibitors as a potential therapeutic strategy.
Project description:To analyze the effect of type I IFN on global gene expression in differentiating monocytes, we employed microarray-based gene expression profiling. The MACS-purified mouse BM monocytes were cultured in M-CSF and treated with or without IFN for 60 h. The cells were harvested and isolated RNAs were subjected to microarray analyses.
Project description:Timecourse experiment (0hr, 2hr,6hr and 21hr) where RNA was extracted from non-rested PBMCs which were exposed to 4 different conditions- nothing (mock), interferon (IFN)gamma, IFN gamma and a non-specific antibody and IFN gamma with purified patient antibody. The purified patient antibody is demonstrated to have a specific anti-interferon gamma effect over time, with the expression profile in the arrays with IFN gamma plus patient antibody most closely resembling the mock arrays. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Using regression correlation