Regulator Of Neutrophil Production Research Articles

Whole blood transcriptomics reveals granulocyte colony-stimulating factor as a mediator of cardiopulmonary bypass-induced systemic inflammatory response syndrome.

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. Twenty-one 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 and whole blood transcriptomics and measured individual mediators in plasma/serum to characterise SIRS induced by CPB. 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 h 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. 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.

Socs3b regulates the development and function of innate immune cells in zebrafish.

Suppressor of cytokine signaling 3 (SOCS3) is a critical component of the negative feedback regulation that controls signaling by cytokines and other factors thereby ensuring that important processes such as hematopoiesis and inflammation occur at appropriate levels. To gain further insights into SOCS3 function, the zebrafish socs3b gene was investigated through analysis of a knockout line generated using CRISPR/Cas9-mediated genome editing. Zebrafish socs3b knockout embryos displayed elevated numbers of neutrophils during primitive and definitive hematopoiesis but macrophage numbers were not altered. However, the absence of socs3b reduced neutrophil functionality but enhanced macrophage responses. Adult socs3b knockout zebrafish displayed reduced survival that correlated with an eye pathology involving extensive infiltration of neutrophils and macrophages along with immune cell dysregulation in other tissues. These findings identify a conserved role for Socs3b in the regulation of neutrophil production and macrophage activation.

Elevated Granulocyte Colony-stimulating Factor Levels in Patients With Active Phase of Adult-onset Still Disease.

Neutrophilia is a hallmark of adult-onset Still disease (AOSD). We aimed to investigate the levels of granulocyte colony-stimulating factor (G-CSF), an essential regulator of neutrophil production and function, in the pathogenesis of AOSD. Sera were collected from 70 patients with AOSD and 20 healthy controls (HCs). The levels of G-CSF were determined by ELISA. Low-density granulocytes (LDGs) were quantified by flow cytometry. Correlations between G-CSF levels and disease activity, laboratory variables, and LDG levels in patients with AOSD were analyzed by Spearman correlation test. Patients with active AOSD presented significantly higher levels of G-CSF compared to inactive AOSD patients (P < 0.001) and HCs (P < 0.0001). The G-CSF levels were significantly decreased after active AOSD patients achieved disease remission (P = 0.0015). The G-CSF levels were significantly correlated with C-reactive protein, erythrocyte sedimentation rate, ferritin, and systemic score in AOSD (P < 0.0001). Significant correlations between the levels of G-CSF and circulating neutrophils (P < 0.0001), neutrophil-to-lymphocyte ratio (P < 0.0001), percentages of LDGs in the peripheral blood mononuclear cells (P = 0.004), as well as absolute numbers of circulating LDGs (P = 0.018) were identified. Patients with fever, evanescent rash, sore throat, arthralgia, myalgia, lymphadenopathy, or hepatomegaly/elevated liver enzymes displayed significantly higher levels of G-CSF compared to patients without these manifestations (P < 0.05). Our findings indicate that G-CSF is implicated in the pathogenesis of AOSD, and targeting G-CSF may have therapeutic potential for AOSD. In addition, introducing circulating G-CSF levels into the clinical assessment system may help to monitor disease activity.

G-CSF and Neutrophils Are Nonredundant Mediators of Murine Experimental Autoimmune Uveoretinitis

Granulocyte colony-stimulating factor (G-CSF) is a regulator of neutrophil production, function, and survival. Herein, we investigated the role of G-CSF in a murine model of human uveitis-experimental autoimmune uveoretinitis. Experimental autoimmune uveoretinitis was dramatically reduced in G-CSF-deficient mice and in anti-G-CSF monoclonal antibody-treated, wild-type (WT) mice. Flow cytometric analysis of the ocular infiltrate in WT mice with experimental autoimmune uveoretinitis showed a mixed population, comprising neutrophils, macrophages, and T cells. The eyes of G-CSF-deficient and anti-G-CSF monoclonal antibody-treated WT mice had minimal neutrophil infiltrate, but no change in other myeloid-derived inflammatory cells. Antigen-specific T-cell responses were maintained, but the differentiation of pathogenic type 17 helper T cells in experimental autoimmune uveoretinitis was reduced with G-CSF deficiency. We show that G-CSF controls the ocular neutrophil infiltrate by modulating the expression of C-X-C chemokine receptors 2 and 4 on peripheral blood neutrophils, as well as actin polymerization and migration. These data reveal an integral role for G-CSF-driven neutrophil responses in ocular autoimmunity, operating within and outside of the bone marrow, and also identify G-CSF as a potential therapeutic target in the treatment of human uveoretinitis.

Mice lacking both G-CSF and IL-6 are more susceptible to Candida albicans infection: Critical role of neutrophils in defense against Candida albicans

Neutrophils play an important role in the host's defense against infection with various pathogenic organisms. Granulocyte colony stimulating factor (G-CSF) is regarded as a major regulator of neutrophil production and function. Mice lacking G-CSF or its receptor are neutropenic. IL-6 is another cytokine that has been shown to promote neutrophil production and modulate the function of many types of immune cells. We have analyzed G-CSF/IL-6 double deficient (G-CSF− / − /IL-6− / − ) mice to gain an insight into the possible contribution of IL-6 to the residual granulopoiesis in G-CSF-deficient (G-CSF− / − ) mice. Furthermore, we have evaluated the ability of G-CSF− / − /IL-6− / − mice to combat an experimental infection with Candida albicans. Our data shows that IL-6 plays a role in granulopoiesis during early post natal period but it is dispensable for steady-state granulopoiesis in adult mice. However, adult G-CSF− / − /IL-6− / − mice are more susceptible to Candida infection than similarly infected G-CSF− / − mice. Although, the candidacidal function of neutrophils of G-CSF− / − /IL-6− / − mice is deficient, the ability to produce IFN-γ and TNF-α in response to Candida infection is not compromised. Similarly, nitric oxide production by peritoneal macrophages from G-CSF− / − /IL-6− / − mice in response to Candida is comparable to G-CSF− / − mice.