ABSTRACT: Chronic exposure to fluticasone propionate shapes gene expression and modulates innate and adaptive activation pathways in human macrophages (LPS)
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 (INF)
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: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: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:Innate immune memory is the phenomenon whereby innate immune cells such as monocytes or macrophages undergo functional reprogramming after exposure to microbial components such as LPS. We apply an integrated epigenomic approach to characterize the molecular events involved in LPS-induced tolerance in a time dependent manner. ChIP-seq, RNA-seq, WGBS and ATAC-seq data were generated. This analysis identified epigenetic programs in tolerance and trained macrophages, and the potential transcription factors involved.
Experimental set-up
Time-course in vitro culture of human monocytes. Two innate immune memory states can be induced in culture through an initial exposure of primary human monocytes to either LPS or BG for 24 hours, followed by removal of stimulus and differentiation to macrophages for an additional 5 days. Cells were collected at baseline (day 0), 1 hour, 4 hour, 24 hour and 6 days.
Project description:A wide variety of electrophilic derivatives of the Kreb’s cycle-derived metabolite, itaconate, are immunomodulatory, yet these derivatives have overlapping and sometimes contradictory activities. Therefore, we generated a genetic system to interrogate the immunomodulatory functions of endogenously produced itaconate in human macrophages. Endogenous itaconate is driven by multiple innate signals restraining inflammatory cytokine production. Endogenous itaconate directly targets cysteine 13 in IRAK4 disrupting IRAK4 autophosphorylation and activation, drives the degradation of NFκB, and modulates global ubiquitination patterns. As a result, cells unable to make itaconate overproduce inflammatory cytokines such as TNFα, IL6, and IL-1β in response to these innate activators. In contrast, the production of IFNβ, downstream of LPS, requires the production of itaconate. These data demonstrate that itaconate is a critical arbiter of inflammatory cytokine production downstream of multiple innate signaling pathways laying the groundwork for the development of itaconate mimetics for the treatment of autoimmunity.
Project description:RNA-seq of 24 M-CSF differentiated human peripheral monocyte-derived macrophages (MDMs) activated with short exposure (3hours) to LPS, or long exposure (24 hours) to LPS, LPS with IFNγ, IFNγ, IL-4, IL-10, and dexamethasone.
