Genome-wide gene expression analysis during endotoxin tolerance in PBMCs.
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ABSTRACT: Genome-wide gene expression was measured in peripheral blood mononuclear cells (PBMC) from healthy humans donors, four hours post stimulation of a single or double treatment of LPS and compared to untreated control PBMCs. We show that a second treatment with LPS induces endotoxin tolerance, with a transcription profile similar to that seen during alternative polarization (M2) of mononuclear cells. Microarray processing was performed by the Genome BC Microarray Platform. Total RNA obtained from PBMCs from blood from healthy humans after single treatment with LPS, two treatments with LPS, or untreated. Comparison of LPS or LPS/LPS to untreated cells shows the gene expression pattern of endotoxin tolerance.
Project description:Genome-wide gene expression was measured in peripheral blood mononuclear cells (PBMC) from healthy humans donors, four hours post stimulation of a single or double treatment of LPS and compared to untreated control PBMCs. We show that a second treatment with LPS induces endotoxin tolerance, with a transcription profile similar to that seen during alternative polarization (M2) of mononuclear cells. Microarray processing was performed by the Genome BC Microarray Platform.
Project description:Endotoxin/LPS tolerance is a tightly regulated phenomenon, which, during infection, prevents systemic hyper-inflammation. Here we report for the first time that morphine reversal of endotoxin tolerance resulting in persistent inflammation thus contributing to septicemia and septic shock. We further report that this regulation is mediated by LPS-induced down-regulation of microRNAs 146a and 155. However, only over-expression of miR-146a, but not miR-155 abrogates morphine mediated hyper-inflammation, while antagonizing miR-146a (but not miR-155) augments morphine mediated hyper-inflammation. Hence, miR-146a could be the potential therapeutic target for morphine-mediated abrogation of endotoxin tolerance.
Project description:The rapid development in septic patients of features of marked immunosuppression associated with increased risk of nosocomial infections and mortality represents the rational for the initiation of immune targeted treatments in sepsis. However, as there is no clinical sign of immune dysfunctions, the current challenge is to develop biomarkers that will help clinicians identify the patients that would benefit from immunotherapy and monitor its efficacy. Using an in vitro model of endotoxin tolerance (ET), a pivotal feature of sepsis-induced immunosuppression in monocytes, we identified using gene expression profiling by microarray a panel of transcripts associated with the development of ET which expression was restored after immunostimulation with interferon-gamma (IFN-M-NM-3). These results were confirmed by qRT-PCR. Importantly, this short-list of markers was further evaluated in patients. Of these transcripts, six (TNFAIP6, FCN1, CXCL10, GBP1, CXCL5 and PID1) were differentially expressed in septic shock patientsM-bM-^@M-^Y blood compared to healthy blood upon ex vivo LPS stimulation and were restored by IFN-M-NM-3. In this study, by combining a microarray approach in an in vitro model and a validation in clinical samples, we identified a panel of six transcripts that could be used for the identification of septic patients eligible for IFNg therapy. The potential value of these markers should now be evaluated in a larger cohort of patients. Upon favorable results, they could serve as stratification tools prior to immunostimulatory treatment and to monitor drug efficacy. PBMCs from 6 healthy donor were left unstimulated (medium) or with 1 shot of LPS (LPS unprimed), 2 shots of LPS (LPS primed) or 2 shots of LPS and Interferon gamma (LPS primed + IFNg).
Project description:Endotoxin/LPS tolerance is a tightly regulated phenomenon, which, during infection, prevents systemic hyper-inflammation. Here we report for the first time that morphine reversal of endotoxin tolerance resulting in persistent inflammation thus contributing to septicemia and septic shock. We further report that this regulation is mediated by LPS-induced down-regulation of microRNAs 146a and 155. However, only over-expression of miR-146a, but not miR-155 abrogates morphine mediated hyper-inflammation, while antagonizing miR-146a (but not miR-155) augments morphine mediated hyper-inflammation. Hence, miR-146a could be the potential therapeutic target for morphine-mediated abrogation of endotoxin tolerance. All treatments done in vivo. Morphine implanted subcuteniously, LPS administered as intraperitoneal injection.
Project description:Background: Sepsis involves aberrant immune responses to infection, but the exact nature of this immune dysfunction remains poorly defined. Bacterial endotoxins like lipopolysaccharide (LPS) are potent inducers of inflammation, which has been associated with the pathophysiology of sepsis, but repeated exposure can also induce a suppressive effect known as endotoxin tolerance or cellular reprogramming. It has been proposed that endotoxin tolerance might be associated with the immunosuppressive state that was primarily observed during late-stage sepsis. However, this relationship remains poorly characterised. Here we clarify the underlying mechanisms and timing of immune dysfunction in sepsis. Methods: We defined a gene expression signature characteristic of endotoxin tolerance. Gene-set test approaches were used to correlate this signature with early sepsis, both newly and retrospectively analysing microarrays from 593 patients in 11 cohorts. Then we recruited a unique cohort of possible sepsis patients at first clinical presentation in an independent blinded controlled observational study to determine whether this signature was associated with the development of confirmed sepsis and organ dysfunction. Findings: All sepsis patients presented an expression profile strongly associated with the endotoxin tolerance signature (p < 0.01; AUC 96.1%). Importantly, this signature further differentiated between suspected sepsis patients who did, or did not, go on to develop confirmed sepsis, and predicted the development of organ dysfunction. Interpretation: Our data support an updated model of sepsis pathogenesis in which endotoxin tolerance-mediated immune dysfunction (cellular reprogramming) is present throughout the clinical course of disease and related to disease severity. Thus endotoxin tolerance might offer new insights guiding the development of new therapies and diagnostics for early sepsis.
Project description:In this study, the transcriptome of peripheral blood mononuclear cells (PBMCs) of a healthy adult was investigated in response to in vitro treatment with LPS, beta-glucan and 1,25(OH)2D3.
Project description:Background: Sepsis involves aberrant immune responses to infection, but the exact nature of this immune dysfunction remains poorly defined. Bacterial endotoxins like lipopolysaccharide (LPS) are potent inducers of inflammation, which has been associated with the pathophysiology of sepsis, but repeated exposure can also induce a suppressive effect known as endotoxin tolerance or cellular reprogramming. It has been proposed that endotoxin tolerance might be associated with the immunosuppressive state that was primarily observed during late-stage sepsis. However, this relationship remains poorly characterised. Here we clarify the underlying mechanisms and timing of immune dysfunction in sepsis. Methods: We defined a gene expression signature characteristic of endotoxin tolerance. Gene-set test approaches were used to correlate this signature with early sepsis, both newly and retrospectively analysing microarrays from 593 patients in 11 cohorts. Then we recruited a unique cohort of possible sepsis patients at first clinical presentation in an independent blinded controlled observational study to determine whether this signature was associated with the development of confirmed sepsis and organ dysfunction. Findings: All sepsis patients presented an expression profile strongly associated with the endotoxin tolerance signature (p < 0.01; AUC 96.1%). Importantly, this signature further differentiated between suspected sepsis patients who did, or did not, go on to develop confirmed sepsis, and predicted the development of organ dysfunction. Interpretation: Our data support an updated model of sepsis pathogenesis in which endotoxin tolerance-mediated immune dysfunction (cellular reprogramming) is present throughout the clinical course of disease and related to disease severity. Thus endotoxin tolerance might offer new insights guiding the development of new therapies and diagnostics for early sepsis. For the RNA-Seq study reported here, 73 patients were recruited with deferred consent at the time of first examination in an emergency ward based on the opinion of physicians that there was a potential for the patient's condition to develop into sepsis. These were retrospectively divided into groups based on clinical features and compared to 11 non-urgent surgical controls.
Project description:Monocyte exposure to lipopolysaccharide (LPS) induces a transient state in which these cells are refractory to further endotoxin stimulation. Here we demonstrate the transcriptome analysis of in vitro generated LPS refractory monocytes upon subsequent re-exposure to LPS for different time points. Total RNA obtained from human monocyte exposure treated with LPS for 3h, 6h, or 24h, subsequent to endotoxin tolerization or not.
Project description:Monocyte exposure to lipopolysaccharide (LPS) induces a transient state in which these cells are refractory to further endotoxin stimulation. Here we demonstrate the transcriptome analysis of in vitro generated LPS refractory monocytes upon subsequent re-exposure to LPS for different time points.
Project description:As cows progress from pregnancy to lactation, the adipose tissues (AT) undergo adaptations characterized by the mobilization of free fatty acids (FFA) through lipolysis to address energy deficiencies. Typically, in clinically healthy cows, the intensity of lipolysis decreases during lactation. However, when the release of FFA surpasses tissue requirements, it leads to the accumulation of lipid-derived products, heightening the susceptibility of cows to metabolic and infectious diseases. A second factor correlated to disease incidence in dairy cows is the presence of bacterial endotoxins in blood. The last is implicated in AT lipolysis and dysfunction in mammals. However, the mechanisms by which endotoxin activates lipolysis and affects the formation of lipid derived products in bovine adipocyte remains unknown. We hypothesize that endotoxin triggers AT dysfunction by increasing the synthesis and release of lipid-derived products with proinflammatory potential. Preadipocytes were obtained from subcutaneous AT of multiparous Holstein cows (n=9). Adipogenesis was induced for 7 d and cells were incubated with endotoxin [lipopolysaccharide 1µg/mL (LPS)] for up to 7 h. Beta-adrenergic receptor agonist isoproterenol (ISO; 1 µM) was used as an activator of canonical lipolysis. The antilipolytic effect of insulin was evaluated alone or in combination with LPS. Lipolysis was evaluated by the release of glycerol in the media. RNA from adipocytes was sequenced in Illumina NextSeqData, and Differential Expressed Genes (DEG) identified. Enrichment and network analyses were performed in Ingenuity Pathways (IPA). Our findings provide evidence supporting the higher abundance of lipid-derived products with proinflammatory activity and dysfunction related to inflammatory activation.