ABSTRACT: Chronic exposure to fluticasone propionate shapes gene expression and modulates innate and adaptive activation pathways in human macrophages (INF)
Project description:Chronic exposure to fluticasone propionate shapes gene expression and modulates innate and adaptive activation pathways in human macrophages
Project description:Chronic exposure to fluticasone propionate shapes gene expression and modulates innate and adaptive activation pathways in human macrophages (LPS)
Project description:Here we investigate how glucocorticoids affect the response to LPS in human macrophages. Total RNA obtained from monocyte-derived macrophages exposed to lipopolysacharide presceding exposure to fluticasone propionate or left untreated.
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:Synthetic amorphous silica (SAS) is a nanomaterial used in a wide variety of applications, including the use as a food additive. Two types of SAS are commonly employed as a powder additive, precipitated silica and fumed silica. Numerous studies have investigated the effects of synthetic amorphous silica on mammalian cells. However, most of them have used an exposure scheme based on a single dose of SAS. In this study, we have used instead a repeated 10-days exposure scheme, closer to the occupational exposure encountered in daily life. As a biological model we have used the murine macrophage cell line J774A.1, as macrophages are very important innate immune cells in the response to particulate materials. In order to get a better appraisal of the macrophage responses to this repeated exposure to SAS, we have used proteomics as a wide-scale approach. Furthermore, some of the biological pathways detected as modulated by the exposure to SAS by the proteomic experiments have been validated through targeted experiments. Overall, proteomics showed that precipitated SAS induced a more important macrophage response than fumed SAS at equal dose. Nevertheless, validation experiments showed that most of the responses detected by proteomics are indeed adaptive, as the cellular homeostasis appeared to be maintained at the end of the exposure. For example, the intracellular glutathione levels or the mitochondrial transmembrane potential at the end of the 10 days exposure were similar for SAS-exposed cells and for unexposed cells. Nevertheless, important functions of macrophages such as phagocytosis, TNF and interleukin-6 secretion were up-modulated after exposure, as was the expression of important membrane proteins such as the scavenger receptor or the MAC-1 receptor. These results suggest that repeated exposure to low doses of SAS slightly modulates the immune functions of macrophages, which may alter the homeostasis of the immune system.
Project description:Rationale: Lipopolysaccharide (LPS) is ubiquitous in the environment. Inhalation of LPS has been implicated in the pathogenesis and/or severity of several lung diseases, including pneumonia, chronic obstructive pulmonary disease and asthma. Alveolar macrophages are the main resident leukocytes exposed to inhaled antigens. Objectives: To obtain insight into which innate immune pathways become activated within human alveolar macrophages upon exposure to LPS in vivo.
Project description:Chronic obstructive pulmonary disease (COPD) is characterized by a progressive decline in lung function, caused by exposure to exogenous particles, mainly cigarette smoke (CS). COPD pathogenesis is initiated and perpetuated by an abnormal CS-induced inflammatory response of the lungs, involving both innate and adaptive immunity. Specifically, B cells organized in iBALT structures, as well as macrophages, accumulate in the lungs and contribute to CS-induced emphysema, but the mechanisms thereof remain unclear. Here, we demonstrate that B cell-deficient mice are significantly protected against CS-induced emphysema. Chronic CS exposure led to increased lung compliance, total lung capacity, and mean linear chord length in WT, but not B cell-deficient mice, associated with an increased size and number of iBALT structures. The increased accumulation of macrophages around iBALT and in emphysematous alveolar areas in CS-exposed WT mice coincided with upregulated MMP12 expression. In vitro co-culture experiments using B cells and macrophages demonstrated that B cell-derived IL-10 drives macrophage activation and MMP12 upregulation. In summary, B cell function in iBALT formation in CS-induced emphysema provides a new innovative mechanism, which could be explored as a target for therapeutic intervention in COPD patients. Expression data of mice treated with cigarette smoke. Lung tissue was analysed at four and six months of age.
Project description:Rationale: Lipopolysaccharide (LPS) is ubiquitous in the environment. Inhalation of LPS has been implicated in the pathogenesis and/or severity of several lung diseases, including pneumonia, chronic obstructive pulmonary disease and asthma. Alveolar macrophages are the main resident leukocytes exposed to inhaled antigens. Objectives: To obtain insight into which innate immune pathways become activated within human alveolar macrophages upon exposure to LPS in vivo. In seven healthy humans sterile saline was instilled into a lung segment by bronchoscope, followed by instillation of LPS into the contralateral lung. Six hours later a bilateral bronchoalveolar lavage was performed and whole-genome transcriptional profiling was done (Affymetrix HG-U133 Plus 2.0) on purified alveolar macrophages, comparing cells exposed to saline or LPS from the same individuals.
Project description:Sensing of microbes activates the immune system, depending on functional mitochondria. However, pathogenic bacteria inhibit mitochondria activity by delivering toxins via outer membrane vesicles (OMVs). How innate immune cells respond to pathogenic microbes that target mitochondria remains unclear. Here, we show that macrophages induce mitochondrial apoptosis and the NLRP3 inflammasome in response OMVs. Macrophages treated with OMVs and toxins that cause mitochondria dysfunction cease host protein translation which depletes pro-survival BCL-2 family member, MCL-1, and induces BAK-dependent mitochondrial apoptosis. Mitochondrial apoptosis and potassium ion efflux activate the NLRP3 inflammasome after OMV exposure. Importantly, mitochondrial apoptosis modulates IL-1 serum levels in response to OMVs. Our data highlight how innate immune cells sense infections by monitoring mitochondrial health.
