Project description:CSF-1 is a key regulator of the macrophage lineage. Macrophages are key mediators of inflammation, cancer, and homeostasis and in some cases differentiate from infiltrating blood monocytes. To better understand the the impact of CSF-1 on blood monocytes, transcriptomic changes in ex vivo cultured human whole blood were measured 4 and 24 hrs after addition of CSF-1 and compared to blood cultured without adding CSF-1. The expression of more than 50 genes was induced with geometric means >2-fold relative to unstimulated control conditions (p<0.05) at either 4 or 24 hrs.
Project description:Objectives: Systemic inflammatory response syndrome (SIRS) is a frequent complication of cardiopulmonary bypass (CPB). SIRS is associated with significant morbidity and mortality, but its pathogenesis remains incompletely understood, and as a result biomarkers are lacking, and treatment remains expectant and supportive. This study aimed to understand the pathophysiological mechanisms driving SIRS induced by CPB and identify novel therapeutic targets that might reduce systemic inflammation and improve patient outcomes. Methods: 21 patients undergoing cardiac surgery and CPB were recruited, and blood was sampled before, during and after surgery. SIRS was defined using the American College of Chest Physicians/Society of Critical Care Medicine criteria. We performed immune cell profiling, whole blood transcriptomics and measured individual mediators in plasma/serum to characterise SIRS induced by CPB. Results: Nineteen patients fulfilled criteria for SIRS, with a mean duration of 2.7 days. Neutrophil numbers rose rapidly with CPB and remained elevated for at least 48 hours afterwards. Transcriptional signatures associated with neutrophil activation and degranulation were enriched during CPB. We identified a network of cytokines governing these transcriptional changes, including granulocyte colony stimulating factor (G-CSF), a regulator of neutrophil production and function. Conclusions: We identified neutrophils and G-CSF as major regulators of CPB induced systemic inflammation. Short-term targeting of G-CSF could provide a novel therapeutic strategy to limit neutrophil mediated inflammation and tissue damage in SIRS induced by CPB.
Project description:Human and murine studies showed that granulocyte macrophage colony-stimulating factor (GM-CSF) exerts beneficial effects in intestinal inflammation. To explore whether GM-CSF mediates its effects via monocytes, we analyzed effects of GM-CSF on monocytes in vitro and assessed the immunomodulatory potential of GM-CSF-activated monocytes (GMaM). We used microarray technology and functional assays to characterize GMaM in vitro and used a mouse model of colitis to study GMaM functions in vivo. Peripheral blood monocytes where cultured 16 h with media containing AB serum (control monocytes) or media containing 10 ng/mL GM-CSF and AB serum (GM-CSF activated monocytes). In three independent experiments, total RNA from GMaM and control monocytes was isolated and processed for microarray hybridization.
Project description:Granulocyte-colony stimulating factor (G-CSF) is used to boost granulocyte counts in immunocompromised patients, but its effects on the immune system may be counter productive. We tested the hypothesis that G-CSF mobilized peripheral blood stem cell (PBSC) products are immunologically down regulated based on gene microarray analysis. Ten peripheral blood samples from normal donors for allogeneic PBSC transplantation were obtained before and after administration of G-CSF and tested on Affymetrix Human U133 Plus 2.0 GeneChip® microarrays. Significant changes in gene expression after G-CSF mobilization were reported by controlling the false discovery rate at 5%. Immune-related genes were isolated from the data set and categorized according to probe set annotations and a thorough, independent literature search. We found that G-CSF up-regulated inflammatory and neutrophil activation pathway gene expression; however, adaptive immune-related gene expression, such as antigen presentation, co-stimulation, T cell activation and cytolytic effector pathways, were generally down-regulated. Thus, despite significant increases in stem cells, lymphocytes and antigen presenting cells, G-CSF mobilized PBSC allografts exhibit a suppressive adaptive immune-related gene expression profile. Our data provides an explanation for the potentially immunosuppressive effects observed after G-CSF administration. Experiment Overall Design: This study was approved by the University of Florida Institutional Review Board. Five healthy donors (A-E) for allogeneic PBSC transplantation consented and were mobilized with rHu G-CSF at 10µ/kg/day for five days. Approximately 4mL of venous blood was collected before (Pre-G-CSF) and after (Post-G-CSF) mobilization. Whole blood leukocyte RNA was purified from each sample and used to generate cRNAs which were subsequently hybridized onto Affymetrix Human U133 Plus 2.0 GeneChip® microarrays. Representative genes were successfully validated with quantitative RT-PCR.
Project description:Using single-cell RNA sequencing (10X technology) on CD4+T cells, we report that GM-CSF-activated human blood CD1c+ dendritic cells (DC) (cDC2) drive the differentiation of naïve CD4+ T cells into Tfh1. These Tfh1 cells displayed typical Tfh molecular features, including high levels of PD-1, CXCR5, and ICOS. They co-expressed Bcl6 and T-bet, and secreted large amounts of IL-21 and IFN-γ.
Project description:Human and murine studies showed that granulocyte macrophage colony-stimulating factor (GM-CSF) exerts beneficial effects in intestinal inflammation. To explore whether GM-CSF mediates its effects via monocytes, we analyzed effects of GM-CSF on monocytes in vitro and assessed the immunomodulatory potential of GM-CSF-activated monocytes (GMaM). We used microarray technology and functional assays to characterize GMaM in vitro and used a mouse model of colitis to study GMaM functions in vivo.
Project description:Emergency granulopoiesis refers to the increased production of neutrophils in bone marrow and their release into circulation induced by severe infection. Several studies point to a critical role for granulocyte colony-stimulating factor (G-CSF) as the main mediator of emergency granulopoiesis. However, the consequences of G-CSF stimulation on the transcriptome of neutrophils and their precursors have not yet been investigated in humans. Here, we examine the changes in mRNA expression induced by administration of G-CSF in vivo, as a model of emergency granulopoiesis in humans. Blood samples were collected from healthy individuals after five days of G-CSF administration. Neutrophil precursors were sorted into discrete stages of maturation by flow cytometry, and RNA was subjected to microarray analysis. mRNA levels were compared to previously published expression levels in corresponding populations of neutrophil precursors isolated from bone marrow of untreated, healthy individuals. 1110 mRNAs were differentially expressed more than 2-fold throughout terminal granulopoiesis. Major changes were seen in pathways involved in apoptosis, cytokine signaling, and Toll-like receptor pathways. In addition, G-CSF treatment reduced the levels of four out of five measured granule proteins in mature neutrophils including the proantibacterial protein hCAP-18, which was completely deficient in neutrophils from G-CSF-treated donors. These results indicate that multiple biological processes are altered in order to satisfy the increased demand for neutrophils during G-CSF-induced emergency granulopoiesis in humans.