interleukin-8 and Pneumonia--Pneumococcal

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide. During pneumococcal pneumonia, the human airway epithelium is exposed to large amounts of H2O2 as a product of host and pathogen oxidative metabolism. Airway cells are known to be highly vulnerable to oxidant damage, but the pathophysiology of oxidative stress induced by S. pneumoniae and the role of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant systems of the host are not well characterized.. For gluthation/gluthathion disulfide analysis BEAS-2B cells, primary broncho-epithelial cells (pBEC), explanted human lung tissue and mouse lungs were infected with different S. pneumoniae strains (D39, A66, R6x, H2O2/pneumolysin/LytA- deficient mutants of R6x). Cell death was proven by LDH assay and cell viability by IL-8 ELISA. The translocation of Nrf2 and the expression of catalase were shown via Western blot. The binding of Nrf2 at the catalase promoter was analyzed by ChIP.. We observed a significant induction of oxidative stress induced by S. pneumoniae in vivo, ex vivo, and in vitro. Upon stimulation, the oxidant-responsive transcription factor Nrf2 was activated, and catalase was upregulated via Nrf2. The pneumococci-induced oxidative stress was independent of S. pneumoniae-derived H2O2 and pneumolysin but depended on the pneumococcal autolysin LytA. The Nrf2 inducer resveratrol, as opposed to catalase, reversed oxidative stress in lung epithelial cells.. These observations indicate a H2O2-independent induction of oxidative stress in lung epithelial cells via the release of bacterial factors of S. pneumoniae. Resveratrol might be an option for prevention of acute lung injury and inflammatory responses observed in pneumococcal pneumonia.

Topics: Animals; Antioxidants; Autolysis; Bacterial Proteins; Cell Line; Cell Survival; Epithelial Cells; Glutathione; Glutathione Disulfide; Humans; Hydrogen Peroxide; Interleukin-8; Lung; Mice; NF-E2-Related Factor 2; Oxidative Stress; Pneumonia, Pneumococcal; Resveratrol; Stilbenes; Streptococcus pneumoniae; Streptolysins

In severe pneumococcal pneumonia, the delicate balance between a robust inflammatory response necessary to kill bacteria and the loss of organ function determines the outcome of disease. In this study, we tested the hypothesis that Krueppel-like factor (KLF) 4 may counter-regulate Streptococcus pneumoniae-related human lung epithelial cell activation using the potent proinflammatory chemokine IL-8 as a model molecule. Pneumococci induced KLF4 expression in human lung, in primary human bronchial epithelial cells, and in the lung epithelial cell line BEAS-2B. Whereas proinflammatory cell activation depends mainly on the classical Toll-like receptor 2-mitogen-activated protein kinase or phosphatidylinositide 3-kinase and NF-κB pathways, the induction of KLF4 occurred independently of these molecules but relied, in general, on tyrosine kinase activation and, in part, on the src kinase family member yamaguchi sarcoma viral oncogene homolog (yes) 1. The up-regulation of KLF4 depended on the activity of the main pneumococcal autolysin LytA. KLF4 overexpression suppressed S. pneumoniae-induced NF-κB and IL-8 reporter gene activation and release, whereas small interfering RNA-mediated silencing of KLF4 or yes1 kinase led to an increase in IL-8 release. The KLF4-dependent down-regulation of NF-κB luciferase activity could be rescued by the overexpression of the histone acetylase p300/cAMP response element-binding protein-associated factor. In conclusion, KLF4 acts as a counter-regulatory transcription factor in pneumococci-related proinflammatory activation of lung epithelial cells, thereby potentially preventing lung hyperinflammation and subsequent organ failure.

Topics: Bacterial Proteins; Cell Line; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Interleukin-8; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; N-Acetylmuramoyl-L-alanine Amidase; Pneumonia, Pneumococcal; Promoter Regions, Genetic; Respiratory Mucosa; Signal Transduction; Streptococcus pneumoniae; Toll-Like Receptor 9

The advanced-age, frail elderly are especially vulnerable to developing pneumococcal infection and disease. Macrophages are critical mediators in the defence against Streptococcus pneumoniae at the upper respiratory tract, however, little is known of their anti-pneumococcal capacity in the elderly. Herein we demonstrate that monocyte-derived macrophages (MDMs) from the advanced-age, frail elderly produce less TNF, IL-6, IL-1β and IL-8 in response to heat-killed S. pneumoniae, which does not appear to be related to mRNA stability or decay. Furthermore, despite maintaining the ability to bind and phagocytose bacteria, MDMs from these individuals have a reduced capacity to kill S. pneumoniae. These defects parallel reduced PI3K-AKT signaling, which can significantly abrogate bacterial killing, but does not affect cytokine responses. Since macrophages are critical in the defence against S. pneumoniae, this study adds valuable insight into the susceptibility of the elderly to pneumococcal disease and highlights the PI3K-AKT signaling pathway as a potential therapeutic target.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Androstadienes; Chromones; Disease Susceptibility; Frail Elderly; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; Macrophages; Middle Aged; Morpholines; Phagocytosis; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Pneumonia, Pneumococcal; Proto-Oncogene Proteins c-akt; Signal Transduction; Streptococcus pneumoniae; Tumor Necrosis Factor-alpha; Wortmannin; Young Adult

Twenty‑three clinical Streptococcus pneumoniae (SP) strains were isolated from blood and sputum specimens from the Second Affiliated Hospital of Wenzhou Medical College in 2009. These strains and the ATCC 49619 standard strain were cultured and suspended in normal saline (at a turbidity of 1.0 McFarland). The production of interleukin (IL)‑8, intracellular adhesion molecule‑1 (ICAM‑1) and IL‑10 in THP‑1 cells following stimulation with the SP suspension was analyzed by an enzyme-linked immunosorbent assay. The concentrations of IL‑8, ICAM‑1 and IL‑10 from the THP‑1 monocytes were greater than those of the blank control following stimulation with the SP suspension. No significant difference was identified in the levels of IL‑8, ICAM‑1 and IL‑10 secretion between THP‑1 monocytes stimulated by blood‑borne SP (bb‑SP) and sputum‑borne SP (sb‑SP).

Topics: Aminoacyltransferases; Cells, Cultured; DNA, Bacterial; Enzyme-Linked Immunosorbent Assay; Humans; Intercellular Adhesion Molecule-1; Interleukin-10; Interleukin-8; Monocytes; Penicillin-Binding Proteins; Pneumonia, Pneumococcal; Real-Time Polymerase Chain Reaction; Sputum; Streptococcus pneumoniae

Cell surface expression of sialic acid has been reported to decrease during immune cell activation, but the significance and regulation of this phenomenon are still being investigated. The major human bacterial pathogen Streptococcus pneumoniae causes pneumonia, sepsis and meningitis, often accompanied by strong inflammatory responses. S. pneumoniae expresses a sialidase (NanA) that contributes to mucosal colonization, platelet clearance, and blood-brain barrier penetration. Using wild-type and isogenic NanA-deficient mutant strains, we showed that S. pneumoniae NanA can desialylate the surface of human THP-1 monocytes, leading to increased ERK phosphorylation, NF-κB activation, and proinflammatory cytokine release. S. pneumoniae NanA expression also stimulates interleukin-8 release and extracellular trap formation from human neutrophils. A mechanistic contribution of unmasking of inhibitory Siglec-5 from cis sialic acid interactions to the proinflammatory effect of NanA is suggested by decreased SHP-2 recruitment to the Siglec-5 intracellular domain and RNA interference studies. Finally, NanA increased production of proinflammatory cytokines in a murine intranasal challenge model of S. pneumoniae pneumonia.

Topics: Animals; Bacterial Proteins; Cell Line; Humans; Interleukin-8; Leukocytes; Mice; Neuraminidase; Pneumonia, Pneumococcal; Streptococcus pneumoniae

Adherence of Streptococcus pneumoniae bacteria to lung cells is a first step in the progression from asymptomatic carriage to pneumonia. Adherence abilities vary widely among S. pneumoniae patient isolates. In this study, the binding properties of S. pneumoniae isolates and the effects of binding on activation of the Nuclear Factor-Kappa-B (NFkappaB) pathway and cytokine secretion by type II pneumocytes were measured.. Mechanisms of high- and low-binding S. pneumoniae adherence to A549 cells were investigated by blocking putative receptors on bacteria and host cells with antibody and by eluting choline-binding proteins off of bacterial surfaces. NFkappaB activation was measured by western blot and immunocytochemistry and cytokine secretion was detected by a protein array.. This study shows that S. pneumoniae isolates from pneumonia patients (n = 298) can vary by as much as 1000-fold in their ability to bind to human lung epithelial cells. This difference resulted in differential activation of the NFkappaB pathway. High-, but not low-binding S. pneumoniae used Choline-binding protein A (CbpA) to bind to complement component C3 on epithelial cell surfaces. Interleukin-8 (IL-8) was the only cytokine secreted by cells treated with either low- or high-binding S. pneumoniae.. These results indicate that S. pneumoniae clinical isolates are not homogeneous in their interaction with host epithelial cells. The differential activation of host cells by high- and low-binding S. pneumoniae strains could have implications for the treatment of pneumococcal pneumonia and for vaccine development.

Topics: Bacterial Adhesion; Cell Line; Humans; Inflammation; Interleukin-8; NF-kappa B; Pneumonia, Pneumococcal; Pulmonary Alveoli; Streptococcus pneumoniae

Interleukin (IL)-8 is a chemotactic cytokine that binds with high affinity to receptors on neutrophils. Previously we showed that (99m)Tc-labeled IL-8 is highly suitable for scintigraphic imaging in rabbit models of IM infection and of colitis.. (99m)Tc-labeled IL-8 was tested for its potential to image pulmonary infection in three experimental rabbit models: aspergillosis in immunocompromised rabbits, pneumococcal (Gram-positive) pneumonia, and Escherichia coli-induced (Gram-negative) pneumonia in immunocompetent rabbits (four rabbits in each group). A derivative of hydrazinonicotinamide was used as bifunctional coupling agent to label IL-8 with (99m)Tc. Biodistribution of (99m)Tc IL-8 was determined both by gamma-camera imaging and by counting dissected tissues at 6 h after injection.. (99m)Tc IL-8 enabled early (within 2 h after injection) and excellent visualization of localization and extent of pulmonary infection in each of the three experimental models of pulmonary infection. Uptake of (99m)Tc IL-8 in the infected lung and the contralateral lung was (in percentage of the injected dose per gram of tissue +/- SEM) at 6 h after injection 0.63 +/- 0.12 and 0.12 +/- 0.02 (aspergillosis), 0.89 +/- 0.04 and 0.44 +/- 0.04 (pneumococcal pneumonia), and 1.53 +/- 0.12 and 0.36 +/- 0.06 (E coli pneumonia), respectively. In the E coli model, uptake of (99m)Tc IL-8 in the focus of infection even exceeded uptake in the kidneys, the main clearing organs.. (99m)Tc IL-8 offers many advantages over the conventionally used radiopharmaceuticals to image pulmonary infection, (67)Ga citrate and radiolabeled leukocytes, ie, rapid and easy preparation, short time span between injection and imaging, low radiation burden and, most importantly, clear delineation of the infectious foci.

Topics: Animals; Aspergillosis; Escherichia coli Infections; Immunocompromised Host; Interleukin-8; Lung; Lung Diseases, Fungal; Organotechnetium Compounds; Pneumonia, Bacterial; Pneumonia, Pneumococcal; Rabbits; Radionuclide Imaging; Radiopharmaceuticals

To understand how neutrophils are recruited to the lung in pneumococcal pneumonia, the ability of pneumococcal components to elicit the chemokine interleukin (IL)-8 from monolayers of cultured human type II cells was assessed. Heat-killed clinical and laboratory strains of Streptococcus pneumoniae and secreted proteins from exponentially growing pneumococci elicited significant quantities of IL-8 from A549 cells. All strains that elicited IL-8 production secreted a protein ( approximately 90 kDa) that comigrated on SDS-PAGE with a C3-binding protein previously identified in S. pneumoniae. As little as 7 pmol of the purified 90-kDa protein readily elicited levels of IL-8 production equivalent to those obtained with 1 U of IL-1alpha. Supernatant proteins and heat-killed cells of an isogenic mutant that failed to produce the C3-binding protein elicited significantly less IL-8 than did supernatant proteins or heat-killed cells of the parent strain. These results implicate the C3-binding protein of S. pneumoniae in a novel pathway of pulmonary inflammation.

Topics: Bacterial Proteins; Carrier Proteins; Cells, Cultured; Electrophoresis, Polyacrylamide Gel; Epithelial Cells; Humans; Interleukin-8; Lung; Molecular Weight; Pneumonia, Pneumococcal; Streptococcus pneumoniae

The role of cytokines in the pathogenesis of pneumonia is still poorly understood. In a previous study the diagnostic value of measuring blood concentrations of interleukin 6 and interferon gamma was established. In the present study the value of blood concentrations of interleukin 8, granulocyte-colony stimulating factor, and lactoferrin as markers of bacteraemic pneumonia is evaluated.. The circulating concentrations of interleukin 8 (IL-8), granulocyte-colony stimulating factor (G-CSF), and lactoferrin were measured in 14 patients with bacteraemic pneumococcal pneumonia and 49 patients with atypical pneumonia or influenza A infection using enzyme immunoassays.. Serum G-CSF concentrations were higher in the group with bacteraemic pneumococcal pneumonia, and G-CSF values correlated with the white blood cell count and levels of C-reactive protein (CRP). The levels of IL-8 were higher in the group with bacteraemic pneumococcal pneumonia than the groups with Chlamydia pneumonia, Legionella pneumonia, or influenza A infection, but there was no difference when compared with the group with Mycoplasma pneumonia. A white blood cell count of > 15 x 10(9)/l was highly suggestive of bacteraemic pneumonia. The concentrations of lactoferrin were raised in all groups except those with influenza A infection, but no difference was found between the different aetiological groups. A correlation was found between lactoferrin and white blood cell counts.. Serum G-CSF and IL-8 concentrations are potential markers of bacteraemic pneumonia.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Biomarkers; Chlamydia Infections; Cytokines; Female; Granulocyte Colony-Stimulating Factor; Humans; Influenza A virus; Influenza, Human; Interleukin-8; Lactoferrin; Legionnaires' Disease; Leukocyte Count; Male; Middle Aged; Pneumonia, Bacterial; Pneumonia, Mycoplasma; Pneumonia, Pneumococcal

One hundred five (70%) of 151 patients hospitalized in the intensive care unit and undergoing mechanical ventilation had bronchial secretions that tested positive for interleukin-8 within 36 hours of admission. Arterial blood, mixed venous blood, and urine collected simultaneously all tested negative, except for 11 patients admitted with intra-abdominal septic foci. The presence of interleukin-8 in the pulmonary air space early in the course of hospitalization was significantly associated with patients with multiple injuries, the need for greater ventilatory support, the occurrence of pulmonary dysfunction, and a 66% incidence of nosocomial bacterial pneumonia. We conclude that the early local production of interleukin-8 in the lungs is an early marker of pulmonary injury and may be involved in the pathogenesis of nosocomial bacterial pneumonia.

Topics: Adult; Blotting, Northern; Bronchi; Cross Infection; Female; Humans; Intensive Care Units; Interleukin-8; Male; Middle Aged; Multiple Trauma; Pneumonia, Pneumococcal; Prospective Studies

To evaluate the influence of vitamin C on pulmonary antibacterial mechanisms, normal CD-1 mice were administered sodium ascorbate (200 mg/kg/24 h) and challenged intratracheally with type 3 Streptococcus pneumoniae. Survival rates were similar in ascorbate-treated and control animals. When infected with a high inoculum (1 X 10(6) cfu), animals given vitamin C demonstrated a significant enhancement in their capacity to clear viable pneumococci from the lungs at 24 h after challenge; the augmented pulmonary clearance was associated with an increased influx of granulocytes at 6 and 24 h. After infection with a lower inoculum (1 X 10(5) cfu), animals treated with the vitamin exhibited a significant advantage in pulmonary clearance and granulocyte recruitment but at 6 h only. After a very low inoculum challenge (1 X 10(4) cfu), the clearance of viable pneumococci was retarded in ascorbate-treated mice. In vitro, the pneumococcidal capacity of resident alveolar macrophages from animals given vitamin C was significantly reduced, but the ability of these cells to generate leukocyte chemoattractant activity after stimulation with the calcium ionophore A23187 remained unaltered. We conclude that in the mouse, large doses of vitamin C alter pulmonary defense mechanisms against S. pneumoniae; however, these changes do not appear to convey a substantial advantage to the host.

Topics: Animals; Ascorbic Acid; Biomechanical Phenomena; Chemotactic Factors; Inflammation; Interleukin-8; Lung; Macrophages; Mice; Mice, Inbred Strains; Neutrophils; Pneumonia, Pneumococcal; Pulmonary Alveoli; Streptococcus pneumoniae