Project description:Although the accumulation of neutrophils in the lungs and airways is common to many inflammatory lung diseases, including acute lung injury, the alterations that neutrophils undergo as they leave the peripheral circulation and migrate into the lungs have not been well characterized. Human volunteers were exposed to endotoxin by bronchoscopic instillation. The resulting air space neutrophil accumulation and peripheral blood neutrophils were isolated 16 h later, compared with circulating neutrophils isolated before or after to the pulmonary endotoxin exposure, and compared with circulating neutrophils exposed to endotoxin in vitro. Microarray analysis was performed on air space, circulatory, and in vitro endotoxin-stimulated neutrophils. Functional analysis included the determination of neutrophil apoptosis, chemotaxis, release of cytokines and growth factors, and superoxide anion release. Dramatic gene expression differences were apparent between air space and circulating neutrophils: approximately 15% of expressed genes have altered expression levels, including broad increases in inflammatory- and chemotaxis-related genes, as well as antiapoptotic and IKK-activating pathways. Functional analysis of air space compared with circulating neutrophils showed increased superoxide release, diminished apoptosis, decreased IL-8-induced chemotaxis, and a pattern of IL-8, macrophage inflammatory protein-1beta, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha release different from either unstimulated or LPS-stimulated circulating neutrophils. Many of these changes are not elicited by in vitro treatment with endotoxin. Limited differences were detected between circulating neutrophils isolated before and 16 h after pulmonary endotoxin instillation. These results suggest that neutrophils sequestered in the lung become fundamentally different from those resident in the circulation, and this difference is distinct from in vitro activation with endotoxin.
Project description:Compared to circulating neutrophils (NC cells), splenic neutrophils (NBH cells) have an activated phenotype and enhanced B cell-helper activity. The transcriptome analysis of splenic and circulating neutrophils was performed to verify whether the enhanced B cell-helper activity of splenic neutrophils correlated with a specific gene signature. Unstimulated neutrophils were FACS sorted from the peripheral blood and spleen of six adult healthy subjects for RNA isolation and Agilent analysis.
Project description:Compared to circulating neutrophils (NC cells), splenic neutrophils (NBH cells) have an activated phenotype and enhanced B cell-helper activity. The transcriptome analysis of splenic and circulating neutrophils was performed to verify whether the enhanced B cell-helper activity of splenic neutrophils correlated with a specific gene signature.
Project description:Polymorphonuclear cells (neutrophils) play an important role in the systemic inflammatory response syndrome and the development of sepsis. These cells are essential for the defense against microorganisms, but may also cause tissue damage. Therefore, neutrophil numbers and activity are considered to be tightly regulated. Previous studies have investigated gene transcription during experimental endotoxemia in whole blood and peripheral blood mononuclear cells. However, the gene transcription response of the circulating pool of neutrophils to systemic inflammatory stimulation in vivo is currently unclear. We examined neutrophil gene transcription kinetics in healthy human subjects (n=4) administered a single dose of endotoxin (LPS, 2 ng/kg iv). In addition, freshly isolated neutrophils were stimulated ex vivo with LPS, TNFM-NM-1, G-CSF and GM-CSF to identify stimulus-specific gene transcription responses. Whole transcriptome microarray analysis of circulating neutrophils at 2, 4 and 6 hours after LPS infusion revealed activation of inflammatory networks which are involved in signaling of TNFM-NM-1 and IL-1M-NM-1 and IL-1M-NM-2. The transcriptome profile of inflammatory activated neutrophils in vivo reflects extended survival and regulation of inflammatory responses. We show that these changes in neutrophil transcriptome are most likely due to a combination of early activation of circulating neutrophils by TNFM-NM-1 and G-CSF and a mobilization of young neutrophils from the bone marrow. After LPS infusion blood was taken at t=0, t=2, t=4 and t=6 hours. Neutrophils were isolated and gene expression of these cells was assessed. T=2, t=4 and t=6 were related to t=0 as control condition
Project description:Neutrophils are the most abundant leukocytesin human peripheral blood and are essential components of the innate immune system. Until recently, neutrophils were thought to be homogeneous and transcriptionally inactive, but both concepts are being challenged by a growing body of data. To date, neutrophils have been characterized based on discrete parameters like cell-surface markers, buoyancy, maturity, or tissue localization.Single-cell RNA sequencing (scRNA-seq) has been an important addition to the set of analytical tools, as itoffers an unbiased view of cells along a continuum of transcriptional states, including those that fall between theoretically more stable endpoints. However, the use of scRNA-seqto characterize transcriptional variation in neutrophils has proven technically difficult, explaining in part the paucity of published single-cell data on neutrophils compared to other celltypes. We report a modified analysis pipeline that substantially increases the detection of human neutrophils in scRNA-seq. We applied this pipeline to the study of > 185,000 human neutrophils. Our findings indicate that circulating human neutrophils are transcriptionally heterogeneous cells, which can be classified based on their transcriptional state into one of four clusters that are highly reproducible among healthy human subjects. We demonstrate that neutrophils shiftfrom relatively immature (Nh0) cells, through a transitional phenotype (Nh1), into one of two endpoints defined by either relative transcriptional inactivity (Nh2) or high expression oftype I interferon-induciblegenes (Nh3).Transitions among states are characterized by the expression of specific transcription factors. By simultaneouslymeasuring surface proteinand intracellular transcriptabundance at the single-cell level, we show that these four transcriptional subsets are independent of the canonical surface proteins that are commonly used to define and characterize human neutrophils.These findings provide a new view of human neutrophil heterogeneity, along a continuum of transcriptional states, with potential implications for the characterization of neutrophils in health and disease.
Project description:Colorectal cancer represents a major public health problem in France because of its high incidence and severe prognosis. Early stages of the disease are well know and have justified the establishment of a mass screening strategy. Unfortunately, the factors determining the progression to metastatic disease about them much harder to grasp. Various prognostic factors and predictors of treatment response have been identified and are being used but most of them are In practice, they are sometimes coarse and relatively little discriminant for patients.
It is now possible to directly quantify the amount of circulating tumor cells in peripheral blood. Quantification of circulating tumor cells beyond a threshold of 3 cells/7,5 ml has been established as a major prognostic factor, and the rapid decrease in the number of these cells under treatment is also a predictor of response for patients suffering from metastatic colorectal cancer . Furthermore, it has also been shown that the quality and importance of the systemic and peritumoral inflammatory response in carcinomas, including colorectal, played a key role in the prognosis of patients. In particular, the presence of high levels of blood neutrophils has been raised by many studies as being followed by a poorer prognosis.
However, the correlation between the presence of circulating tumor cells and high levels of neutrophils has never been studied. There is a rational to assume that this association exists, and secondly that the presence of circulating tumor cells in a proinflammatory environment represented by a high levels of blood neutrophils promotes metastasis by exerting a negative synergistic effect on the prognosis of patients.
The main objective of this pilot study is to find a correlation between the amount of circulating neutrophils and the presence of circulating tumor cells in patients with colon cancer metastatic unresectable non-pretreated. The secondary objective is to investigate whether this association results in a negative synergistic effect in terms of progression-free survival and survival to one year. This is a non-interventional study. The investigators expect the inclusion in one year of thirty patients in two centers (University Hospital Centre Antoine Lacassagne Nice) to achieve these goals.
Project description:Polymorphonuclear cells (neutrophils) play an important role in the systemic inflammatory response syndrome and the development of sepsis. These cells are essential for the defense against microorganisms, but may also cause tissue damage. Therefore, neutrophil numbers and activity are considered to be tightly regulated. Previous studies have investigated gene transcription during experimental endotoxemia in whole blood and peripheral blood mononuclear cells. However, the gene transcription response of the circulating pool of neutrophils to systemic inflammatory stimulation in vivo is currently unclear. We examined neutrophil gene transcription kinetics in healthy human subjects (n=4) administered a single dose of endotoxin (LPS, 2 ng/kg iv). In addition, freshly isolated neutrophils were stimulated ex vivo with LPS, TNFα, G-CSF and GM-CSF to identify stimulus-specific gene transcription responses. Whole transcriptome microarray analysis of circulating neutrophils at 2, 4 and 6 hours after LPS infusion revealed activation of inflammatory networks which are involved in signaling of TNFα and IL-1α and IL-1β. The transcriptome profile of inflammatory activated neutrophils in vivo reflects extended survival and regulation of inflammatory responses. We show that these changes in neutrophil transcriptome are most likely due to a combination of early activation of circulating neutrophils by TNFα and G-CSF and a mobilization of young neutrophils from the bone marrow.
Project description:It was previously demonstrated that myeloid cells assume a distinct transcriptional profile when infiltrating the brain during chronic inflammation. We demonstrated that neutrophils infiltrate the brain during pancreatic cancer. To determine if the transcriptional profile of brain-infiltrating neutrophils is distinct from those infiltrating other organs, we compared the gene signatures of brain-infiltrating neutrophils, circulating neutrophils, liver-infiltrating neutrophils, and tumor-infiltrating neutrophils to that of circulating neutrophils from healthy mice.
Project description:During systemic inflammation, different neutrophil subsets are mobilized to the blood circulation. These neutrophil subsets can be distinguished from normal circulating neutrophils (CD16bright/CD62Lbright) based on either an immature CD16dim/CD62Lbright or a CD16bright/CD62Ldim phenotype. Interestingly, the latter neutrophil subset is known to suppress lymphocyte proliferation ex vivo, but the underlying mechanism is largely unknown. We performed transcriptome analysis on the different neutrophil subsets to identify changes that are relevant for their functions. Neutrophil subsets were isolated by FACS sorting from the blood of healthy volunteers who were administered a single dose of lipopolysaccharide (LPS). The transcriptome was determined by microarray. The mobilized neutrophil subsets were characterized by specific transcriptome profiles reflecting their phase in neutrophil lifespan. Interestingly, the CD16bright/CD62Ldim suppressive neutrophils showed an interferon-induced transcriptome profile. This was confirmed by stimulation of peripheral neutrophils with IFNgamma. These cells acquired the capacity to suppress lymphocyte proliferation through the expression of programmed death ligand 1 (PD-L1). These data demonstrate that the suppressive phenotype of the neutrophil subset is induced by IFNgamma. Specific stimulation of neutrophils might have a pivotal role in regulating lymphocyte-mediated inflammation and autoimmune disease. After LPS infusion, blood was taken at t=0 and t=4 hours. Neutrophils were FACS sorted based on CD16 and CD62L expression. Gene expression of neutrophil subsets was assessed relative to t=0 as control.
Project description:Pulmonary dendritic cells are heterogenous cells comprise four distinct subsets including two conventional dendritic cell subsets, CD103+ and CD11bhiCD14lo cells, and two monocyte-derived dendritic cell subsets. Their functions in terms of migration and T cell activation are distinct, but genes regulating their features are to be determined. We used microarrays to identify a select set of genes that are expressed in conventinal dendritic cells and in monocyte-derived dendriti cells. Four distinct lung DC subsets were purified by flow cytometry-based sorting after inhalation of lipopolusaccharide and ovalbumin. Each subset has three replicates.