Lipocalin-2 Functions as Inhibitor of Innate Resistance to .

Lipocalin-2 is a constituent of the neutrophil secondary granules and is expressed by macrophages and epithelium in response to inflammation. Lipocalin-2 acts in a bacteriostatic fashion by binding iron-loaded siderophores required for bacterial growth. (M.

Human adult HSCs can be discriminated from lineage-committed HPCs by the expression of endomucin.

EMCN is a novel marker of human HSCs. EMCN is a more specific marker of HSCs than CD34 as it can discriminate HSCs from lineage-committed HPCs.

Applying label-free dynamic mass redistribution assay for studying endogenous FPR1 receptor signalling in human neutrophils.

Introduction: The label-free dynamic mass redistribution-based assay (DMR) is a powerful method for studying signalling pathways of G protein-coupled receptors (GPCRs). Herein we present the label-free DMR assay as a robust readout for pharmacological characterization of formyl peptide receptors (FPRs) in human neutrophils.

Methods: Neutrophils were isolated from fresh human blood and their responses to FPR1 and FPR2 agonists, i.

Prolonged pharmacological inhibition of cathepsin C results in elimination of neutrophil serine proteases.

Cathepsin C (CatC) is a tetrameric cysteine dipeptidyl aminopeptidase that plays a key role in activation of pro-inflammatory serine protease zymogens by removal of a N-terminal pro-dipeptide sequence. Loss of function mutations in the CatC gene is associated with lack of immune cell serine protease activities and cause Papillon-Lefèvre syndrome (PLS). Also, only very low levels of elastase-like protease zymogens are detected by proteome analysis of neutrophils from PLS patients.

MicroRNA-941 Expression in Polymorphonuclear Granulocytes Is Not Related to Granulomatosis with Polyangiitis.

Jumonji Domain-Containing Protein 3 (JMJD3)/lysine demethylase 6B (KDM6B) is an epigenetic modulator that removes repressive histone marks on genes. Expression of KDM6B mRNA is elevated in leukocytes from patients with ANCA-associated vasculitis (AAV) and has been suggested to be the reason for higher proteinase 3 (PR3) mRNA expression in these cells due to derepression of PRTN3 gene transcription. MicroRNA-941 (miR-941) has been shown to target KDM6B mRNA and inhibit JMJD3 production.

Granulopoiesis and granules of human neutrophils.

Granules are essential for the ability of neutrophils to fulfill their role in innate immunity. Granule membranes contain proteins that react to environmental cues directing neutrophils to sites of infection and initiate generation of bactericidal oxygen species. Granules are densely packed with proteins that contribute to microbial killing when liberated to the phagosome or extracellularly.

Changes in Gene Expression during G-CSF-Induced Emergency Granulopoiesis in Humans.

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 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.

Extracellular superoxide dismutase is present in secretory vesicles of human neutrophils and released upon stimulation.

Extracellular superoxide dismutase (EC-SOD) is an antioxidant enzyme present in the extracellular matrix (ECM), where it provides protection against oxidative degradation of matrix constituents including type I collagen and hyaluronan. The enzyme is known to associate with macrophages and polymorphonuclear leukocytes (neutrophils) and increasing evidence supports a role for EC-SOD in the development of an inflammatory response. Here we show that human EC-SOD is present at the cell surface of isolated neutrophils as well as stored within secretory vesicles.

Neutrophil extracellular traps - the dark side of neutrophils.

Neutrophil extracellular traps (NETs) were discovered as extracellular strands of decondensed DNA in complex with histones and granule proteins, which were expelled from dying neutrophils to ensnare and kill microbes. NETs are formed during infection in vivo by mechanisms different from those originally described in vitro. Citrullination of histones by peptidyl arginine deiminase 4 (PAD4) is central for NET formation in vivo.

Impact of microRNA-130a on the neutrophil proteome.

Background: MicroRNAs (miRNAs) are important for the development and function of neutrophils. miR-130a is highly expressed during early neutrophil development and regulates target proteins important for this process. miRNA targets are often identified by validating putative targets found by in silico prediction algorithms one at a time.

Plasma levels of OLFM4 in normals and patients with gastrointestinal cancer.

Olfactomedin 4 (OLFM4) is a secreted glycoprotein predominantly expressed in bone marrow and gastrointestinal tissues. Aberrant expression of OLFM4 has been shown in several cancers. However, the clinical significance hereof is currently controversial.

A novel mechanism for NETosis provides antimicrobial defense at the oral mucosa.

Neutrophils are essential for host defense at the oral mucosa and neutropenia or functional neutrophil defects lead to disordered oral homeostasis. We found that neutrophils from the oral mucosa harvested from morning saliva had released neutrophil extracellular traps (undergone NETosis) in vivo. The NETosis was mediated through intracellular signals elicited by binding of sialyl Lewis(X) present on salival mucins to l-selectin on neutrophils.

The antimicrobial propeptide hCAP-18 plasma levels in neutropenia of various aetiologies: a prospective study.

The underlying cause of neutropenia may be difficult to determine due to similar clinical presentation in many neutropenic conditions. The neutrophil protein hCAP-18 (pro-LL-37) is a major component of neutrophil secondary granules and in this prospective study we assessed the use of hCAP-18 levels in blood plasma for differential diagnosis of neutropenic patients (n = 133) of various aetiologies. Plasma levels of hCAP-18 were determined using immunoblot and ELISA.

Interplay between enterobactin, myeloperoxidase and lipocalin 2 regulates E. coli survival in the inflamed gut.

During an inflammatory response in the gut, some commensal bacteria such as E. coli can thrive and contribute to disease. Here we demonstrate that enterobactin (Ent), a catecholate siderophore released by E.

Processing of Neutrophil α-Defensins Does Not Rely on Serine Proteases In Vivo.

The α-defensins, human neutrophil peptides (HNPs) are the predominant antimicrobial peptides of neutrophil granules. They are synthesized in promyelocytes and myelocytes as proHNPs, but only processed in promyelocytes and stored as mature HNPs in azurophil granules. Despite decades of search, the mechanisms underlying the posttranslational processing of neutrophil defensins remain unidentified.

Papillon-Lefèvre syndrome patient reveals species-dependent requirements for neutrophil defenses.

Papillon-Lefèvre syndrome (PLS) results from mutations that inactivate cysteine protease cathepsin C (CTSC), which processes a variety of serine proteases considered essential for antimicrobial defense. Despite serine protease-deficient immune cell populations, PLS patients do not exhibit marked immunodeficiency. Here, we characterized a 24-year-old woman who had suffered from severe juvenile periodontal disease, but was otherwise healthy, and identified a homozygous missense mutation in CTSC indicative of PLS.

Liver is the major source of elevated serum lipocalin-2 levels after bacterial infection or partial hepatectomy: a critical role for IL-6/STAT3.

Unlabelled: Lipocalin-2 (LCN2) was originally isolated from human neutrophils and termed neutrophil gelatinase-associated lipocalin (NGAL). However, the functions of LCN2 and the cell types that are primarily responsible for LCN2 production remain unclear. To address these issues, hepatocyte-specific Lcn2 knockout (Lcn2(Hep-/-)) mice were generated and subjected to bacterial infection (with Klesbsiella pneumoniae or Escherichia coli) or partial hepatectomy (PHx).

ADAM9 is a novel product of polymorphonuclear neutrophils: regulation of expression and contributions to extracellular matrix protein degradation during acute lung injury.

A disintegrin and a metalloproteinase domain (ADAM) 9 is known to be expressed by monocytes and macrophages. In this study, we report that ADAM9 is also a product of human and murine polymorphonuclear neutrophils (PMNs). ADAM9 is not synthesized de novo by circulating PMNs.

Neutrophils at work.

In this Review we discuss data demonstrating recently recognized aspects of neutrophil homeostasis in the steady state, granulopoiesis in 'emergency' conditions and interactions of neutrophils with the adaptive immune system. We explore in vivo observations of the recruitment of neutrophils from blood to tissues in models of blood-borne infections versus bacterial invasion through epithelial linings. We examine data on novel aspects of the activation of NADPH oxidase and the heterogeneity of phagosomes and, finally, consider the importance of two neutrophil-derived biological agents: neutrophil extracellular traps and ectosomes.

Human α-defensin expression is not dependent on CCAAT/enhancer binding protein-ε in a murine model.

Specific granule deficiency (SGD) is a rare congenital disorder characterized by recurrent infections. The disease is caused by inactivating mutations of the CCAAT/enhancer binding protein-ε (C/EBP-ε) gene. As a consequence, specific and gelatinase granules lack most matrix proteins.

Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells.

Production of the human cathelicidin antimicrobial peptide gene (hCAP18/LL-37), is regulated by 1α,25-dihydroxyvitamin D3 (1,25D3) and is critical in the killing of pathogens by innate immune cells. In addition, secreted LL-37 binds extracellular receptors and modulates the recruitment and activity of both innate and adaptive immune cells. Evidence suggests that during infections activated immune cells locally produce increased levels of 1,25D3 thus increasing production of hCAP18/LL-37.