Monokine-induced Neutrophil Chemotactic Factor Gene Expression in Human Fibroblasts

Circ_0026579 knockdown ameliorates lipopolysaccharide-induced human lung fibroblast cell injury by regulating CXCR1 via miR-370-3p

Pneumonia is an inflammatory disease in lower respiratory tracts and its development involves the regulation of RNAs. Circular RNAs are a class of RNA subgroups that can mediate the progression of pneumonia. However, the molecular mechanism of circ_0026579 in regulating pneumonia occurrence remains unclear. The study is designed to reveal the role of circ_0026579 in lipopolysaccharide (LPS)-induced human lung fibroblast cell injury and the underlying mechanism. The expression levels of circ_0026579, miR-370-3p and C-X-C motif chemokine receptor 1 (CXCR1) were detected by quantitative real-time polymerase chain reaction or by western blotting. The production of tumour necrosis factor-α, interleukin (IL)-1β and IL-6 was assessed by enzyme-linked immunosorbent assays. Malondialdehyde and superoxide dismutase levels were analysed using commercial kits. Cell viability, proliferation and apoptosis were analysed by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay and flow cytometry analysis, respectively. The binding relationship between miR-370-3p and circ_0026579 or CXCR1 was identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Circ_0026579 and CXCR1 expression were significantly upregulated, whereas miR-370-3p was downregulated in the serum of pneumonia patients. LPS treatment induced inflammatory response, oxidative stress and cell apoptosis and inhibited cell proliferation in MRC-5 cells; however, these effects were reversed after circ_0026579 depletion. In terms of the mechanism, circ_0026579 acted as a miR-370-3p sponge, and miR-370-3p combined with CXCR1. Additionally, circ_0026579 depletion ameliorated LPS-induced MRC-5 cell disorder by increasing miR-370-3p expression. CXCR1 overexpression also relieved the miR-370-3p-mediated effects in LPS-treated MRC-5 cells. Further, circ_0026579 induced CXCR1 expression by interacting with miR-370-3p. Circ_0026579 absence ameliorated MRC-5 cell dysfunction induced by LPS through the regulation of the miR-370-3p/CXCR1 axis.

Intravital Imaging of Myeloid Cells: Inflammatory Migration and Resident Patrolling

Myeloid cell recruitment to sites of infection and injury started out as a simple model that has been referred to as the universal concept of leukocyte recruitment. However, as we gain more insight into the different mechanisms, it is becoming clear that each organ and perhaps even each cell has its own unique mechanism of recruitment. Moreover, as the ability to visualize specific cell types in specific organs becomes more accessible, it is also becoming clear that there are resident populations of leukocytes, some within the tissues and others attached to the vasculature of tissues, the latter poised to affect the local environment. In this review, we will first highlight the imaging approaches that have allowed us to gain spectacular insight into locale and function of specific cell types, and then we will discuss what we have learned from this approach as far as myeloid cells are concerned. We will also highlight some of the gaps in our knowledge, which exist almost certainly because of the challenges of being able to visualize certain compartments of the body.

Effect of Amentoflavone on the Inhibition of Pulmonary Metastasis Induced by B16F-10 Melanoma Cells in C57BL/6 Mice

This study was an investigation of the antimetastatic activity of amentoflavone using B16F-10 melanoma—induced experimental lung metastasis in C57BL/6 mice. Amentoflavone treatment significantly reduced tumor nodule formation accompanied by reduced lung collagen hydroxyproline, hexosamine, and uronic acid levels. Serum sialic acid and γglutamyl transpeptidase levels were also significantly inhibited after amentoflavone treatment. Amentoflavone treatment up-regulated the lung tissue inhibitor of metalloprotease-1 and tissue inhibitor of metalloprotease-2 expression. The cytokine profile and growth factors such as interleukin-1β , interleukin-6, tumor necrosis factor-α, granulocyte monocyte— colony stimulating factor, vascular endothelial growth factor, interleukin-2, and tissue inhibitor of metalloprotease-1 in the serum of these animals were markedly altered after amentoflavone treatment. This altered level of cytokines after amentoflavone treatment was also accompanied by enhanced natural killer cell antibody—dependent cellular cytotoxicity. The study reveals that amentoflavone treatment could alter proinflammatory cytokine production and could inhibit the activation and nuclear translocation of p65, p50, c-Rel subunits of nuclear factor—κB, and other transcription factors such as c-fos, activated transcription factor—2, and cyclic adenosine monophosphate response element—binding protein in B16F-10 melanoma cells.

Macrophage-secreted IL-8 induces epithelial-mesenchymal transition in hepatocellular carcinoma cells by activating the JAK2/STAT3/Snail pathway

Macrophages are a major component of the leukocyte infiltrate of tumors and play a pivotal role in the progression of hepatocellular carcinoma (HCC). However, the molecular mechanisms by which macrophages promote HCC invasion are poorly understood. The present study was undertaken to investigate the relationship between macrophages and epithelial-mesenchymal transition (EMT) of HCC. Double-staining immunohistochemistry was used to observe the association between macrophages and EMT markers in clinical HCC samples and it showed that EMT primarily occurred at the edge of the tumor nest, in which infiltrating macrophages were always observed. This indicated that CD68 which is a marker of macrophages, was correlated with EMT marker levels. In addition, after being cultured with macrophages for 24 h, the ability of HCC cells to migrate and invade increased, Snail and N-Cadherin expression was upregulated, and E-Cadherin was downregulated. An antibody array assay was applied to analyze the supernatant of these cultures and it demonstrated IL-8 increased significantly in the macrophage co-culture system. Finally, the role of macrophage-derived IL-8 in the invasion of HCC cells was assayed, and downstream signaling pathways were also investigated. We found that IL-8: i) may induce EMT and promote HCC cell migration and invasion and ii) is associated with the JAK2/STAT3/Snail signaling pathway. Taking together, these findings revealed that macrophages that have infiltrated tumors may induce epithelial-mesenchymal transition of HCC cells via the IL-8 activated JAK2/STAT3/Snail pathway. Thus, this may offer a potential target for developing new HCC therapies.

The chemokine receptors CXCR1 and CXCR2 regulate oral cancer cell behaviour

BACKGROUND

Chemokines regulate physiological and pathological leucocyte trafficking, and chemokine receptors play a role in tumorigenesis. Expression of interleukin-8 (IL-8) receptors CXCR1 and CXCR2 has been shown in oral squamous cell carcinoma (OSCC) but remains poorly characterised. This aim of this study was to investigate CXCR1 and CXCR2 expression on normal oral keratinocytes (NOKs) and oral cancer cell lines (OCCL) and their relative response when exposed to IL-8 and growth-related oncogene-α (which selectively binds CXCR2).

METHODS

mRNA and protein expression was studied using RT-PCR, immunocytochemistry and flow cytometry. ELISAs were used to investigate ERK1/2 phosphorylation and MMP production, whereas a MTS-based assay was employed to study proliferation. Migration assays were carried out using modified Boyden chambers with a matrigel coating used for invasion assays.

RESULTS

mRNA expression of CXCR1 and CXCR2 was seen in both NOKs and OCCL with significantly higher protein expression in OCCL. Exposure to IL-8 and GROα increased intracellular ERK phosphorylation, proliferation, migration and invasion with OCCL showing a greater response than NOKs. These effects were mediated through CXCR1 and CXCR2 (for IL-8) and CXCR2 (for GROα) as receptor-blocking antibodies significantly inhibited the responses. IL-8 and GROα also increased MMP-9 release from NOKs and OCCL with significantly higher amounts released by OCCL. However, an increase in MMP-7 production was only seen in OCCL.

CONCLUSIONS

Functional CXCR1 and CXCR2 exist on normal and cancerous oral epithelial cells, and our data suggests a role for these receptors in oral cancer biology.

Fibroblasts stimulated via HLA-II molecules produce prostaglandin E₂ and regulate cytokine production from helper T cells

Fibroblasts act as important immune regulatory cells via their ability to cross-talk with T cells accumulating in lesions. Our previous study showed that fibroblasts produce several cytokines and chemokines by crosslinking HLA class II (HLA-II) molecules with monoclonal antibodies or by making T-cell receptor-peptide-HLA complexes. It is thus conceivable that the interaction of T cells and fibroblasts via HLA-II affects fibroblast responses to stimuli. This study used human gingival fibroblasts (HGF) to investigate possible effects of these fibroblast-derived soluble factors on the differentiation of naïve T cells and on the subsequent fibroblast responses. After mixed lymphocyte reaction culture between naïve T cells and allogeneic dendritic cells in the presence of culture supernatant from HGF stimulated via HLA-DQ molecules (DQ-sup), but not via DR, T cells exhibited a Th2-shifted phenotype, thereby producing quantitatively more IL-13 and IL-5 compared with interferon-γ. Astonishingly, analyses to identify possible factors affecting the Th2 polarization secreted from HLA-II-stimulated HGF, prostaglandin E₂, was detected only in DQ-sup. The Th2 polarization of naïve T cells was blocked in the presence of supernatants from indomethacin-treated HGF with HLA-DQ stimulation. In addition, we found that the culture supernatants of Th cells activated following mixed lymphocyte reaction culture in the presence of DQ-sup had the potential to induce gene expression of type I and III collagens in HGF. These results suggested that fibroblasts stimulated via HLA-DQ molecules promote Th2 polarization in Th-cell responses and showed the counter activation of collagen synthesis, implicating orchestrated responses among these cells in the fibrosis of chronic inflammatory lesions.

TNF-α induces vectorial secretion of IL-8 in Caco-2 cells

INTRODUCTION

Intestinal epithelial cells represent an important component of innate immunity, with sophisticated responses to inflammatory stimuli. The manner in which intestinal epithelial cell polarity affects responses to inflammatory stimuli is largely unknown. We hypothesized that polarized intestinal epithelial cells exhibit a bidirectional inflammatory response dependent upon the location of the stimulus.

METHODS

Caco-2 cells were grown on semi-permeable inserts in a dual-compartment culture system and treated with tumor necrosis factor-α (TNF-α; 100 ng/ml) or serum-free media in the apical or basolateral chamber. Interleukin-8 (IL-8) production in each chamber was measured by enzyme-linked immunosorbent assay. To determine receptor specificity, anti-TNF receptor antibodies were added to the apical or basolateral chamber.

RESULTS

Basolateral stimulation with TNF-α resulted in increased apical and basolateral IL-8 production. Apical TNF-α stimulation resulted in increased apical, but not basolateral IL-8 production. Receptor blockade suggested TNF receptor 1 involvement on both apical and basolateral membranes, while TNF receptor 2 was only active on the apical membrane.

CONCLUSION

Polarized intestinal epithelial cells respond to TNF-α stimulation with focused, directional secretion of the proinflammatory cytokine IL-8. These findings are important because they suggest that intestinal epithelial cells are capable of organizing their response to inflammatory signals and producing inflammatory mediators in a bidirectional, vectorial fashion.

Systemic and local cytokine production in quiescent ulcerative colitis and its relationship to future relapse: a prospective pilot study

BACKGROUND

The main aim of this prospective study was to examine whether systemic (plasma) and local (mucosal) cytokine production is a predictor of future relapse in patients with quiescent ulcerative colitis (UC). The impact of other clinical and laboratory parameters on relapse was also studied.

METHODS

Fifty consecutive patients with quiescent UC were included. At enrollment, blood and mucosal (rectal biopsies) samples were collected. All patients were followed up regularly for 1 year after enrollment. Plasma and mucosal cytokine levels were measured by enzyme-linked immunosorbent assay. To identify independent significant predictive factors for relapse, time-dependent analyses using the Kaplan-Meier method and the Cox proportional hazard model were performed.

RESULTS

Thirty-four patients remained in remission, and 16 patients relapsed during the 1-year follow-up. Higher interleukin (IL)-8 levels in the rectal mucosa were significantly associated with relapse. In contrast, IL-1beta, IL-6, and tumor necrosis factor-alpha levels in the rectal mucosa were not associated with relapse. Conventional blood markers and plasma cytokines (IL-1beta, IL-6, IL-8, and tumor necrosis factor-alpha) did not correlate with relapse. Among clinical factors, age and number of prior relapses were significantly associated with relapse. In multivariate analysis, a higher rectal mucosal IL-8 level (> or = 160 pg/mg of tissue; hazard ratio, 4.7), younger age (<30 yr; hazard ratio, 7.3), and a greater number of prior relapses (> or = 5; hazard ratio, 4.3) were independent significant risk factors for future relapse.

CONCLUSIONS

Rectal mucosal IL-8 measurement might be an additional objective diagnostic tool that can predict relapse in patients with quiescent UC.

The selective prostaglandin EP4 agonist, APS-999 Na, induces follicular growth and maturation in the rat ovary

OBJECTIVE

It is known that prostaglandin E2 (PGE2) plays a crucial role in the ovulation process. PGE2 mediates its actions through four subtypes of receptors designated EP1-EP4. However, the nature of the ovulation-promoting effect of PGE2 is not well understood. We have carried out this in vivo research utilizing a new selective EP4 receptor agonist (EP4A; APS-999 Na) to investigate its role in folliculogenesis aiming at more understanding of the biological mechanism of action of PGE2.

DESIGN AND METHODS

Immature, 22 day old Wistar rats were used. Animals were injected once either with placebo, 20 IU pregnant mare serum gonadotrophin (PMSG), or EP4A (10, 20 or 50 microg). In other experiments, EP4A was injected in PMSG stimulated rats. Ovarian follicle growth and development was assessed through total count and size measurement of ovulatory follicles in whole ovaries of the investigated groups. Utilizing immunohistochemistry, the spatial localization of the EP4 receptor in immature rat ovary and IL-8 pattern of expression after EP4A injection was also investigated.

RESULTS

Our study showed that injection of EP4A resulted in increased follicle growth and development compared with the control, in a time- and dose-dependent manner. The highest values for follicle count and size were observed 12 and 24 h after EP4A injection. EP4A induced follicle growth with morphological characteristics similar to that induced by the standard PMSG. Most dense immune staining for EP4 receptor was noticed in proliferating granulosa cells of the secondary follicles while those of the primordial and primary follicles were not stained. EP4A injection induced the expression of IL-8 in the follicles.

CONCLUSIONS

Our study revealed that: (i) the localization of EP4 receptor in the ovary implies a role in follicle growth, (ii) PGE2 induced ovarian follicle growth and development is mediated at least in part through the EP4 receptor, (iii) the action of EP4A is mediated through IL-8 up regulation and (iv) the new EP4A could be a promising reagent for various systems used to induce follicle maturation in clinical or agricultural fields. This knowledge may provide useful targets for manipulation of infertility.

Role of neutrophils in mucus hypersecretion in COPD and implications for therapy

Airway mucus hypersecretion is a serious and presently untreatable symptom of COPD. Over the past several years, emerging evidence has implicated epidermal growth factor receptor (EGFR) expression and activation in mucin production by airway epithelial (goblet) cells. Activated neutrophils recruited to the airways (and their secreted products) play several key roles in EGFR-dependent mucus hypersecretion: (i) activated neutrophils secrete tumor necrosis factor (TNF)-alpha, which induces EGFR expression in airway epithelial cells; (ii) activated neutrophils release reactive oxygen species, which activate EGFR; (iii) neutrophil elastase cleaves the EGFR proligand, pro-transforming growth factor (TGF)-alpha, releasing mature TGF alpha which activates EGFR in a ligand-dependent fashion; and (iv) neutrophil elastase causes potent goblet cell degranulation. The secretion of active products by neutrophils appears carefully regulated. The local release of neutrophil elastase requires close contact between the neutrophil and another cell, mediated by surface adhesion molecules, thus limiting proteolysis to the immediate pericellular environment. In the airway lumen, neutrophils undergo apoptosis and are cleared by macrophages without releasing their intracellular contents. In contrast, neutrophils that die by necrosis disgorge proteases and reactive oxygen species into the lumen. In COPD, conditions within the airway lumen promote neutrophil necrosis. It is concluded that neutrophil death via necrosis leads to the high concentrations of free neutrophil elastase and reactive oxygen species in the sputum of patients with airway neutrophilia and mucus hypersecretion. Inflammatory cells (neutrophils), molecules (neutrophil elastase and reactive oxygen species), signaling pathways (EGFR), and cellular processes (neutrophil necrosis) contribute to mucus hypersecretion in COPD, and are potential targets for therapy. Interventions that target EGFR, neutrophil elastase, and reactive oxygen species exist and can be evaluated as treatments for neutrophil-dependent mucus hypersecretion.

Role of inducible nitric oxide synthase-derived nitric oxide in lipopolysaccharide plus interferon-gamma-induced pulmonary inflammation

Exposure of mice to lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma) increases nitric oxide (NO) production, which is proposed to play a role in the resulting pulmonary damage and inflammation. To determine the role of inducible nitric oxide synthase (iNOS)-induced NO in this lung reaction, the responses of inducible nitric oxide synthase knockout (iNOS KO) versus C57BL/6J wild-type (WT) mice to aspirated LPS + IFN-gamma were compared. Male mice (8-10 weeks) were exposed to LPS (1.2 mg/kg) + IFN-gamma (5000 U/mouse) or saline. At 24 or 72 h postexposure, lungs were lavaged with saline and the acellular fluid from the first bronchoalveolar lavage (BAL) was analyzed for total antioxidant capacity (TAC), lactate dehydrogenase (LDH) activity, albumin, tumor necrosis factor-alpha (TNF-alpha), and macrophage inflammatory protein-2 (MIP-2). The cellular fraction of the total BAL was used to determine alveolar macrophage (AM) and polymorphonuclear leukocyte (PMN) counts, and AM zymosan-stimulated chemiluminescence (AM-CL). Pulmonary responses 24 h postexposure to LPS + IFN-gamma were characterized by significantly decreased TAC, increased BAL AMs and PMNs, LDH, albumin, TNF-alpha, and MIP-2, and enhanced AM-CL to the same extent in both WT and iNOS KO mice. Responses 72 h postexposure were similar; however, significant differences were found between WT and iNOS KO mice. iNOS KO mice demonstrated a greater decline in total antioxidant capacity, greater BAL PMNs, LDH, albumin, TNF-alpha, and MIP-2, and an enhanced AM-CL compared to the WT. These data suggest that the role of iNOS-derived NO in the pulmonary response to LPS + IFN-gamma is anti-inflammatory, and this becomes evident over time.

The effect of TNF-α, PMA, and LPS on plasma and cell-associated IL-8 in human leukocytes

INTRODUCTION/AIM

This study was performed to examine the proficiency of mononuclear cells (MNC) and polymorphonuclear cells (PMN) in a whole blood model to expressing interleukin-8 (IL-8) in response to various stimuli.

METHODS

Isolated cells that had been recombined with heparinized plasma were incubated with lipopolysaccharide (LPS), phorbol myristate acetate (PMA) and tumor necrosis factor (TNF)-alpha.

RESULTS

IL-8 release by MNC was most potently induced by LPS, reaching significant levels after 2-h incubation in the presence of 0.2 ng/ml LPS. In contrast, 5.0 ng/ml LPS was required for PMN to release significant amounts of the cytokine (P<0.001). When PMN and MNC were coincubated (MNC/PMN), LPS-induced IL-8 release was reduced compared to the release from MNC alone, regardless of the concentration of LPS used. IL-8 release by PMN was much more strongly induced by TNF-alpha, increasing by 1050% in the presence of 10 ng/ml TNF-alpha (P<0.005), whereas MNC or MNC/PMN subjected to this stimulus alone did not significantly enhance their IL-8 release. PMA had no effect on IL-8 release from either cell type. Since a high portion of IL-8 in blood is associated with cells, the IL-8 levels in isolated and lysed cell suspensions were also quantified. Thus, a considerably higher level of IL-8 was found in freshly isolated PMN (0.58+/-0.09 ng/ml) than in MNC (0.010+/-0.007 ng/ml). PMN remained the main source for cell-associated IL-8 after 2-h incubation in the absence of any added stimuli, harbouring a relatively high level of the cytokine (3.37+/-1.38 ng/ml), which was significantly enhanced in the presence of TNF-alpha (8.99+/-1.46 ng/ml, P<0.001).

CONCLUSION

This study shows that LPS is an effective inducer of IL-8 in MNC, whereas TNF-alpha is a potent agonist for IL-8 release from PMN. The main portion of cell-associated IL-8 is present in PMN when the cells are stimulated in their normal environment of plasma.

Intestinal cytokines in children with pervasive developmental disorders

OBJECTIVES

A relationship between autism and gastrointestinal (GI) immune dysregulation has been postulated based on incidence of GI complaints as well as macroscopically observed lymphonodular hyperplasia and microscopically determined enterocolitis in pediatric patients with autism. To evaluate GI immunity, we quantitatively assessed levels of proinflammatory cytokines, interleukin (IL)-6, IL-8, and IL-1beta, produced by intestinal biopsies of children with pervasive developmental disorders.

METHODS

Fifteen patients, six with pervasive developmental disorders and nine age-matched controls, presenting for diagnostic colonoscopy were enrolled. Endoscopic biopsies were organ cultured, supernatants were harvested, and IL-6, IL-8, and IL-1beta levels were quantified by ELISA. Tissue histology was evaluated by blinded pathologists.

RESULTS

Concentrations of IL-6 from intestinal organ culture supernatants of patients with pervasive developmental disorders (median 318.5 pg/ml, interquartile range 282.0-393.0 pg/ml) when compared with controls (median 436.9 pg/ml, interquartile range 312.6-602.5 pg/ml) were not significantly different (p = 0.0987). Concentrations of IL-8 (median 84,000 pg/ml, interquartile range 16,000-143,000 pg/ml) when compared with controls (median 177,000 pg/ml, interquartile range 114,000-244,000 pg/ml) were not significantly different (p = 0.0707). Concentrations of IL-1beta (median 0.0 pg/ml, interquartile range 0.0-94.7 pg/ml) when compared with controls (median 0.0 pg/ml, interquartile range 0.0-60.2 pg/ml) were not significantly different (p = 0.8826). Tissue histology was nonpathological for all patients.

CONCLUSIONS

We have demonstrated no significant difference in production of IL-6, IL-8, and IL-1beta between patients with pervasive developmental disorders and age-matched controls. In general, intestinal levels of IL-6 and IL-8 were lower in patients with pervasive developmental disorders than in age-matched controls. These data fail to support an association between autism and GI inflammation.

The role of interleukin-8 in interstitial pneumonia

OBJECTIVE

A variety of inflammatory cells accumulate in the lungs of patients with interstitial lung disease. The potential for IL-8 to be released from these cells into the lungs of patients with idiopathic interstitial pneumonia (IIP), interstitial pneumonia with collagen vascular disease (IP-CVD), sarcoidosis (SAR) and hypersensitivity pneumonitis (HP) was investigated.

METHODOLOGY

IL-8 levels were assessed by enzyme-linked immunosorbent assay in BAL fluid and serum, and the expression of IL-8 in the lungs of these patients was evaluated by immunohistochemistry.

RESULTS

Serum IL-8 levels were significantly elevated in patients with IIP (P < 0.05) and SAR (P < 0.01). In BAL fluid, the IL-8 level was significantly higher in patients with IIP (P < 0.05), IP-CVD (P < 0.01), SAR (P < 0.01) and HP (P < 0.01). In several cases, IL-8 level correlated with neutrophil density. The IL-8 immunopositive cells were type II pulmonary epithelial cells and alveolar and interstitial macrophages in patients with IIP and IP-CVD.

CONCLUSIONS

IL-8 is likely to be a key factor in the pathogenesis of fibrosis of the lung and in lung injury.

Interleukin-10 inhibits expression of interleukin-6 and -8 mRNA in human dental pulp cell cultures via nuclear factor-kappaB deactivation

The effects of interleukin (IL)-10 on the expression of IL-6 and IL-8 mRNA in human dental pulp cell cultures were investigated by using the Northern blot analysis. On stimulation with Prevotella intermedia lipopolysaccharide (PiLPS), IL-10 was produced in peripheral blood but was not detected in human dental pulp cell culture supernatants. IL-10 inhibited IL-8 mRNA expression, which is normally stimulated by PiLPS, IL-1alpha, and tumor necrosis factor-alpha and inhibited IL-6 mRNA expression, which is normally stimulated by IL-1alpha. In addition, IL-10 inhibited the activation of nuclear factor-kappaB, which is normally induced by PiLPS. We conclude that IL-10 inhibits expression of IL-6 and IL-8 mRNA in dental pulp cell cultures by inhibiting the activation of nuclear factor-kappaB.

Counter-antigen presentation: fibroblasts produce cytokines by signalling through HLA class II molecules without inducing T-cell proliferation

Fibroblasts are known to express histocompatibility leukocyte antigen DR (HLA-DR) molecules on their cell surface upon stimulation with interferon gamma (IFN- gamma), while the exact roles of HLA-DR on fibroblasts remain undetermined. To understand the role of HLA-DR molecules on fibroblasts, we examined whether: (1) fibroblasts act as antigen presenting cells (APC) which activate helper T (Th) cells; and/or (2) fibroblasts are activated via HLA-II molecules by making a T-cell receptor (TCR)-peptide-major histocompatibility complex (MHC) complex. We used Th(0) clone HT8.3, which recognizes an antigenic peptide (Ag53 p141-161) in the context of DRB1*1501, as well as IFN - gamma - treated and irradiated periodontal ligament fibroblasts (PDL) expressing DRB1*1501 molecules. When peptide-pulsed fibroblasts were co-incubated with HT8.3 treated by the protein synthesis inhibitor emetine, peptide-induced de novo expression of lymphokines and cell-surface molecules on T cells can be neglected. The antigen presenting capacity of these fibroblasts was evaluated by examining the proliferative responses of Th cells. Possible activation of fibroblasts by stimulation via HLA-DR molecules was evaluated by quantitating secreted cytokines in the supernatants after 18-h culture with or without anti-HLA-DR monoclonal antibody (mAb) or emetine-treated HT8.3. Indeed, Th cells did not show proliferative responses when peptide-pulsed PDL were used as APC, whereas PDL produced larger amounts of interleukin (IL) 6, IL-8, monocyte chemoattractant protein 1 (MCP-1) and regulated upon activation, normal T expressed and secreted (RANTES) compared with controls, when cultured with anti-HLA-DR mAb or emetine-treated HT8.3. These findings suggest that HLA-DR expressed on fibroblasts do not present antigens to induce T-cell proliferation, but may act as receptor molecules that transmit signals into fibroblasts, based on DR-peptide-TCR interaction, resulting in the secretion of several cytokine species.

The role of interleukin-8 and its receptors in inflammatory lung disease: implications for therapy

Neutrophils have been implicated in the pathogenesis of many inflammatory lung diseases, including the acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. The CXC chemokine interleukin (IL)-8, is a potent neutrophil recruiting and activating factor and the detection of IL-8 in clinical samples from patients with these diseases has led clinicians to believe that antagonism of IL-8 may be a practicable therapeutic strategy for disease management. Work over the last decade has concentrated on both the molecular mechanisms by which IL-8 is produced in the inflammatory setting and also on the manner in which IL-8 activates the neutrophil. Expression of the IL-8 gene appears to be controlled by several components of the inflammatory milieu. Whilst lipopolysaccharide, IL-1beta and tumor necrosis factor-alpha are capable of augmenting IL-8 production, IL-10 is a potent inhibitor of IL-8 synthesis and appears to play an auto-regulatory role. Regulation of the IL-8 gene is under the control of nuclear factor kappaB which appears to be a primary target for corticosteroid-mediated repression of IL-8 production. IL-8 exerts is effects on neutrophils by binding with high affinity to two receptors on its cell surface, the chemokine receptors CXCR1 and CXCR2. These closely related receptors belong to the superfamily of G-protein coupled receptors, proteins that historically have proved amenable to antagonism by small molecules. The recent descriptions in the literature of highly potent small molecule antagonists of CXCR2 and their success in blocking in vivo trafficking of neutrophils suggest that antagonism of IL-8 at the receptor level is a viable therapeutic strategy. Clinical trials of such compounds will ultimately provide crucial information currently lacking and will define whether or not IL-8 blockade provides future therapy in pulmonary disease.

Cyclophosphamide stimulates lung fibroblasts to release neutrophil and monocyte chemoattractants

Cyclophosphamide is an alkylating antineoplastic agent used in several conditions. However, little is known about the mechanism of its pulmonary toxicity. In the present study, we determined that human lung fibroblasts release activity for neutrophils and monocytes in response to cyclophosphamide in a dose- and time-dependent manner. Checkerboard analysis revealed that both neutrophil and monocyte activities were chemotactic. The release of chemotactic activity was inhibited by lipoxygenase inhibitors and cycloheximide. Molecular-sieve column chromatography revealed that both neutrophil (NCA) and monocyte (MCA) chemotactic activities had multiple peaks. NCA was inhibited by a leukotriene B4receptor antagonist and anti-interleukin-8 and anti-granulocyte colony-stimulating factor antibodies. MCA was attenuated by a leukotriene B4receptor antagonist and anti-monocyte chemoattractant protein-1 and anti-granulocyte-macrophage colony-stimulating factor antibodies. The concentrations of interleukin-8, granulocyte colony-stimulating factor, monocyte chemoattractant protein-1, and granulocyte-macrophage colony-stimulating factor significantly increased in response to cyclophosphamide. These data suggest that lung fibroblasts may modulate inflammatory cell recruitment into the lung by releasing NCA and MCA in response to cyclophosphamide.

Interleukin-8 serum and urine concentrations after kidney transplantation

We conducted a prospective study of 12 patients undergoing kidney transplantation. In these patients, we monitored interleukin-8 (IL-8) in both serum and urine before and after kidney transplantation. Levels of IL-8 were analyzed by a solid-phase double ligand ELISA method. Three patients with an uneventful recovery after transplantation showed IL-8 serum levels below the detection limit, whereas some small amounts were detected in the urine of these patients. IL-8 serum levels markedly increased with acute graft rejection and infection. Increments in serum and urine preceded clinical complications in all patients. Highest levels were observed in bacterial infection and lowest in acute rejection. Although nonspecific, IL-8 can be considered as an indicator molecule of inflammatory processes occurring during kidney transplantation.

Determination of Total Interleukin-8 in Whole Blood after Cell Lysis

Background: It has been shown that a high percentage of interleukin-8 (IL-8) in blood is cell associated. Recently, a simple method for determination of cell-associated IL-8 in whole blood after cell lysis has been described. The purpose of this study was to evaluate this method, to examine the influence of preanalytic sample handling, and to establish the concentration range of total IL-8 and its relation to age and sex in healthy subjects.

Methods: Total IL-8 content of whole blood was determined after lysing blood cells with Milenia® cell lysis solution. IL-8 in the resulting blood lysate was measured with the IMMULITE® IL-8 immunoassay.

Results: When freshly drawn blood was stored up to 48 h on ice, no significant changes in total IL-8 were measured in the subsequently prepared lysate, whereas with storage at room temperature, total IL-8 increased after 3 h from 94 ± 13 ng/L to 114 ± 16 ng/L (n = 10). In lysate stored for 48 h at 4 °C, marginal changes of the IL-8 concentration were noted, with storage at room temperature, only 76% ± 5% (n = 12) of initial concentration was recovered. From lysate frozen at −20 and −80 °C, respectively, 84% ± 4% and 93% ± 2% of initial IL-8 was recovered after 70 days (n = 10). IL-8 was measured with comparable precision in plasma (CV, 3.2–4.2%) and blood lysate (CV, 3.7–4.1%). When plasma was diluted with cell lysis solution, a slightly overestimated recovery (125% ± 3%) was observed; for lysate specimens with a cell lysis solution content ≥75%, the recovery after dilution was 98% ± 2%. In lysate prepared from 12 blood samples with exogenous IL-8 added, IL-8 recovery was 104% ± 2% (recovery from plasma &lt;35%). The median total IL-8 in blood lysates from 103 healthy subjects (22–61 years) was 83 ng/L of blood (2.5–97.5 percentile range, 49–202 ng/L of blood). In females but not in males, total IL-8 increased significantly with advancing age (P &lt;0.002). We found grossly increased total IL-8 in six pregnant women with amniotic infection syndrome.

Conclusions: The evaluated method allows the assessment of total IL-8 in blood with good performance when appropriate conditions of sample pretreatment are considered. The values in healthy volunteers all were above the detection limit of the IL-8 assay; therefore, slight changes of total IL-8 could be noted. Thus, the present method is a suitable tool to study the diagnostic relevance of total IL-8 in blood.

IL-8 is an angiogenic factor in human coronary atherectomy tissue

BACKGROUND

Interleukin-8 (IL-8), a CXC chemokine that induces the migration and proliferation of endothelial cells and smooth muscle cells, is a potent angiogenic factor that may play a role in atherosclerosis. Previously, IL-8 has been reported in atherosclerotic lesions and circulating macrophages from patients with atherosclerosis. Therefore, we sought to determine whether IL-8 plays a role in mediating angiogenic activity in atherosclerosis.

METHODS AND RESULTS

Homogenates from 16 patients undergoing directional coronary atherectomy (DCA) and control samples from the internal mammary artery (IMA) of 7 patients undergoing bypass graft surgery were assessed for IL-8 content by specific ELISA, immunohistochemistry, and in situ hybridization for IL-8 mRNA. The contribution of IL-8 to net angiogenic activity was assessed using the rat cornea micropocket assay and cultured cells. IL-8 expression was significantly elevated in DCA samples compared with IMA samples (1.71+/-0.6 versus 0.05+/-0.03 ng/mg of total protein; P<0.01). Positive immunolocalization of IL-8 was found exclusively in DCA tissue sections, and it correlated with the presence of factor VIII-related antigen. In situ reverse transcriptase polymerase chain reaction revealed the expression of IL-8 mRNA in DCA tissue. Corneal neovascular response, defined by ingrowth of capillary sprouts toward the implant, was markedly positive with DCA pellets, but no constitutive vessel ingrowth was seen with IMA specimens. Neutralizing IL-8 attenuated both the in vivo corneal neovascular response and the in vitro proliferation of cultured cells.

CONCLUSIONS

The results suggest that, in human coronary atherosclerosis, IL-8 is an important mediator of angiogenesis and may contribute to plaque formation via its angiogenic properties.

Interleukin 8 (IL-8) and the release of leukocytes from the bone marrow

Interleukin 8 (IL-8) is produced by various cells upon stimulation and influences a variety of functions of leukocytes in particular neutrophils. Systemic administration of IL-8 induces a rapid neutropenia associated by sequestration of neutrophils in the lung that is followed by a neutrophilia characterized by the rapid release of neutrophils from the bone marrow. These cells are released predominantly from the bone marrow venous sinusoids. In addition, several studies have shown the potential role of IL-8 in hematopoiesis and trafficking of hematopoietic stem cells. Systemic administration of IL-8 induces a rapid mobilization of progenitors from the bone marrow with long-term myelo-lymphoid repopulation capacity. It has been employed clinically to mobilize hematopoietic progenitor cells into the peripheral blood and used for autologous or allogeneic bone marrow transplantation. The mechanism for these effects of IL-8 is largely speculative. This report summarizes current ideas on the possible mechanisms how IL-8 influences cell trafficking in and from the bone marrow.

Migration of CD18-deficient neutrophils in vitro: evidence for a CD18-independent pathway induced by IL-8

Neutrophils isolated from a child with severe leukocyte adhesion deficiency 1 (LAD1) had a complete absence of expression of the CD11/CD18 beta2 integrin family of adhesion molecules, and were shown to be deficient in the in vitro adhesion and migration properties. However, we found that interleukin-8 (IL8), a potent chemoattractant for neutrophils, and sputum sol phase induced these LAD1 neutrophils to migrate through an endothelial cell layer in vitro, and confirmed that this migration was CD18-independent. These findings add to evidence of CD18-independent mechanisms of neutrophil recruitment, in particular neutrophil infiltration into the lungs, where IL8 may be an important recruitment factor.

Bradykinin stimulates lung fibroblasts to release neutrophil and monocyte chemotactic activity

Activation of the kallikrein-kinin system in lung injury has long been recognized. However, the effects of bradykinin (BK) on human lung fibroblasts (HLF) remain to be elucidated. We determined whether BK stimulates HLF to release chemotactic activity for neutrophils and monocytes (NCA and MCA, respectively). We evaluated HLF supernatant fluids for chemotactic activity through a blind-well chamber technique. HLF released NCA and MCA in a dose- and time-dependent manner in response to BK. The release of chemotactic activity was inhibited by lipoxygenase inhibitors and cycloheximide. Molecular sieve column chromatography revealed that both NCA and MCA had multiple chemotactic peaks. NCA was inhibited by a leukotriene (LT) B(4) receptor antagonist and by antibodies to interleukin (IL)-8 and granulocyte colony-stimulating factor (G-CSF). MCA was attenuated by the LTB(4) receptor antagonist and by antibodies to monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), and transforming growth factor (TGF)-beta. Both the LTB(4) receptor antagonist and these antibodies inhibited chemotactic activity of the molecular weights corresponding to MCP-1, GM-CSF, and TGF-beta, separated by column chromatography. The concentrations of IL-8, G-CSF, MCP-1, GM-CSF, and TGF-beta in supernatant fluids increased significantly in a time-dependent manner in response to BK. The receptors responsible for the release of NCA, MCA, and individual chemokines included both BKB(1) and BKB(2) receptors. These data suggest that BK may stimulate lung fibroblasts to release inflammatory cytokines, which may modulate lung inflammation.

Chemokines and their role in airway hyper-reactivity

Airway hyper-reactivity is a characteristic feature of many inflammatory lung diseases and is defined as an exaggerated degree of airway narrowing. Chemokines and their receptors are involved in several pathological processes that are believed to contribute to airway hyper-responsiveness, including recruitment and activation of inflammatory cells, collagen deposition and airway wall remodeling. These proteins are therefore thought to represent important therapeutic targets in the treatment of airway hyper-responsiveness. This review highlights the processes thought to be involved in airway hyper-responsiveness in allergic asthma, and the role of chemokines in these processes. Overall, the application of chemokines to the prevention or treatment of airway hyper-reactivity has tremendous potential.

Bleomycin Stimulates Lung Fibroblasts to Release Neutrophil and Monocyte Chemotactic Activity

We determined whether human lung fibroblasts might release chemotactic activity for neutrophils (NCA) and monocytes (MCA) in response to bleomycin. The human lung fibroblasts supernatant fluids were evaluated for chemotactic activity by a blind well chamber technique. Human lung fibroblasts released NCA and MCA in a dose- and time-dependent manner in response to bleomycin. Checkerboard analysis of supernatant fluids revealed that both NCA and MCA were chemotactic. Partial characterization revealed that NCA was partly heat labile, trypsin sensitive, and predominantly ethyl acetate extractable. In contrast, MCA was partly trypsin sensitive and ethyl acetate extractable. The release of chemotactic activity was inhibited by lipoxygenase inhibitors and cycloheximide. Molecular sieve column chromatography revealed that both NCA and MCA had multiple chemotactic peaks. NCA was inhibited by leukotriene B4 receptor antagonist and anti-IL-8 and G-CSF Abs. MCA was attenuated by leukotriene B4 receptor antagonist, and monocyte chemoattractant protein-1, GM-CSF, and TGF-β Abs. Leukotriene B4 receptor antagonist and these Abs inhibited the corresponding m.w. chemotactic activity separated by column chromatography. The concentrations of IL-8, G-CSF, monocyte chemoattractant protein-1, GM-CSF, and TGF-β in the supernatant fluids significantly increased in response to bleomycin. These data suggest that lung fibroblasts may modulate inflammatory cell recruitment into the lung by releasing NCA and MCA in response to bleomycin.

Interleukin-8 induces lymphocyte chemotaxis into the pleural space. Role of pleural macrophages

The pleural space is a potential compartment between the lung and chest wall that becomes filled with fluid and inflammatory cells in a number of respiratory diseases. In an attempt to understand one aspect of the inflammatory process in the pleural space, we compared the responses in three different diseases (congestive heart failure [CHF], tuberculosis [TB], and cancer). Large concentrations of interleukin-8 (IL-8) were detected in cancer and TB effusions, but not in CHF. Surprisingly, the concentration of IL-8 correlated best with lymphocyte recruitment and not with neutrophil recruitment. Pleural fluid from cancer and TB patients was chemotactic for lymphocytes, and this activity was partly blocked by an anti-IL-8 antibody in cancer and completely blocked in TB. To determine whether there was the potential for a chemotactic gradient into the pleural space, pleural effusion cells were analyzed for the expression of IL-8. Cells in the effusions of cancer patients expressed IL-8, whereas IL-8 could not be detected from the cells of TB and CHF effusions. To explore the possible role of pleural macrophages in the regulation of IL-8, pleural effusion cells were treated with culture supernatants from stimulated pleural macrophages. Stimulated pleural macrophages were able to induce expression of messenger RNA (mRNA) for IL-8 and IL-8 protein production, and this activity was abrogated by blocking tumor necrosis factor-alpha. These findings suggest that soluble IL-8 is an important factor for the recruitment of lymphocytes into the pleural space, and that this cytokine is produced by both pleural structural and cancer cells after their activation by macrophage-derived, cytokine-mediated signals.

Bradykinin stimulates interleukin-8 production by human lung fibroblasts

Bradykinin (BK) is a potent inflammatory mediator that is generated from kininogens by the actions of plasma and tissue kallikreins. Lung fibroblasts have the potential to participate in the inflammatory responses by releasing proinflammatory cytokines in response to a variety of stimuli. We postulated that human lung fibroblasts might produce interleukin-8 (IL-8) in response to BK stimulation. The present study showed that BK stimulated human lung fibroblasts to produce IL-8 in a dose- and time-dependent manner. Furthermore, Northern blot analysis showed that BK increased IL-8 mRNA expression. The stimulatory effect of BK on IL-8 production was detected at the concentration of 10 nm, and the maximal stimulation was achieved with 100 to 1000 nm. Phorbol 12-myristate 13-acetate pretreatment diminished the ability of BK to stimulate IL-8 production. In addition, GF109203X, a selective protein kinase C inhibitor, blocked BK-induced IL-8 production. These observations suggest that the stimulatory effect of BK on IL-8 production by lung fibroblasts is, at least partially, mediated through protein kinase C. These data suggest that BK may be involved in the inflammatory reaction leading to interstitial lung disorders through stimulating IL-8 production by lung fibroblasts.

Bradykinin stimulates type II alveolar cells to release neutrophil and monocyte chemotactic activity and inflammatory cytokines

In the present study, we evaluated the potential of bradykinin (BK) to induce the release of neutrophil and monocyte chemotactic activity (NCA and MCA) and cytokines from an alveolar type II epithelial cell line, A549 cells. BK stimulated A549 cells to release NCA and MCA in a dose- and time-dependent manner (P < 0.001). Checkerboard analysis revealed that both NCA and MCA involved chemotactic and chemokinetic activity. Molecular sieve column chromatography showed three molecular weight masses (near 19 kd, 8 kd, and 400 d) for NCA and several molecular weight peaks (near 66 kd, 25 kd, 19 kd, 16 kd, and 400 d) for MCA. The release of NCA and MCA was inhibited by cycloheximide and lipoxygenase inhibitors (P < 0.01). The NCA and MCA were inhibited by leukotriene B4 (LTB4) receptor antagonist (P < 0.01), and the concentration of LTB4 was high enough for NCA and MCA. Antibodies to interleukin (IL)-8 and granulocyte colony-stimulating factor (G-CSF) attenuated NCA (P < 0.01), and antibodies to monocyte chemotactic protein-1 (MCP-1), G-CSF, and transforming growth factor (TGF)-beta attenuated MCA (P < 0.01). The levels of IL-8, G-CSF, MCP-1, and TGF-beta increased time dependently (P < 0.01). BK also stimulated the release of ILeukin-6 from A549 cells (P < 0.001). The receptors responsible for the release of NCA, MCA, and individual chemokines involved both BKB1 and BKB2 receptors. These data suggest that BK may stimulate alveolar type II pneumocytes to release inflammatory cytokines, which then may modulate the lung inflammation.

Alveolar type II-like cells release G-CSF as neutrophil chemotactic activity

We evaluated the potential of A549 cells, an alveolar type II epithelial cell line, to release granulocyte colony-stimulating factor (G-CSF), in addition to interleukin (IL)-8 and leukotriene B4, as neutrophil chemotactic activity (NCA). Human recombinant IL-1beta stimulated A549 cells to release NCA in a time- and dose-dependent fashion. The released NCA was blocked by mouse anti-human G-CSF polyclonal antibody. Molecular-sieve column chromatography revealed that IL-1beta induced the release of a 19- to 20-kDa chemotactic mass that was inhibited by anti-human G-CSF antibody. IL-1beta stimulated the release of G-CSF in a dose-dependent fashion, but the time-dependent profile of G-CSF showed that the concentration of G-CSF declined after 48 h. Tumor necrosis factor (TNF)-alpha, Escherichia coli lipopolysaccharide (LPS), and bradykinin (BK) stimulated A549 cells to release NCA that was inhibited by anti-G-CSF antibody. The release of G-CSF in response to TNF-alpha, LPS, and BK was significantly increased. The similar concentrations of human recombinant G-CSF (10-1,000 pg/ml) as in the supernatant fluid induced neutrophil chemotaxis. G-CSF mRNA was expressed time and dose dependently at 4 h and declined after 4 h in response to IL-1beta as evaluated by RT-PCR. The expression of G-CSF mRNA was also observed by TNF-alpha, LPS, and BK stimulation. These data suggest that type II alveolar epithelial cells may produce G-CSF as NCA and may participate in the regulation of leukocyte extravasation.

The biphasic mRNA expression pattern of bovine interleukin-8 in Pasteurella haemolytica lipopolysaccharide-stimulated alveolar macrophages is primarily due to tumor necrosis factor alpha

Pasteurella haemolytica serotype 1 is the bacterial agent responsible for the pathophysiological events associated with bovine pneumonic pasteurellosis. Our previous studies support a role for the lipopolysaccharide (LPS) from P. haemolytica in the induction of proinflammatory cytokines. One of the pathological hallmarks of bovine pneumonic pasteurellosis is an influx of neutrophils into the alveolar spaces. This pronounced influx suggests the local production of a chemotactic factor(s) such as interleukin-8 (IL-8). In the context of the lung, the alveolar macrophage appears to be the major producer of IL-8, a proinflammatory cytokine with potent neutrophil chemotactic activity. By using Northern blot analysis, we have examined the kinetics of IL-8 mRNA expression in P. haemolytica LPS-stimulated bovine alveolar macrophages and found that 1 ng of LPS per ml induces maximal expression of IL-8 mRNA. The results also indicate a biphasic time course expression pattern in which IL-8 mRNA levels peak between 1 and 2 h in the first phase and between 16 and 24 h in the second phase (P < 0.01). In addition, monospecific polyclonal antibodies were used to demonstrate the role of tumor necrosis factor alpha (TNF-alpha) in the second phase of IL-8 mRNA expression. Our findings support a role for P. haemolytica LPS and TNF-alpha in the induction of IL-8 from bovine alveolar macrophages.

Human lung fibroblasts release chemokinetic activity for monocytes constitutively

We determined whether human lung fibroblasts (HLFs) might release mediators that are responsible for monocyte chemokinetic activity (MCA) constitutively. HLF supernatant fluids showed MCA in a time-dependent manner (P < 0.001). Checkerboard analysis of 24- and 72-h supernatant fluids showed that the activity was chemokinetic. Partial characterization of 24- and 72-h supernatant fluids revealed that the mediators released after 24 h were predominantly composed of lipid-soluble activity, and MCA was blocked by lipoxygenase inhibitors. The mediators released after 72 h were predominantly trypsin sensitive and blocked by cycloheximide. Molecular-sieve column chromatography identified four peaks of MCA. A polyclonal antibody to monocyte chemoattractant protein-1 (MCP-1) inhibited MCA by 20% after 24 h and by 40% after 72 h. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor-beta (TGF-beta) antibodies attenuated MCA released after 72 h by 30 and 10%, respectively. These antibodies inhibited corresponding molecular-weight peaks separated by molecular-sieve column. The concentrations of MCP-1, GM-CSF, and TGF-beta were 4,698 +/- 242, 26.8 +/- 3.8, and 550 +/- 15 pg/ml, respectively. A leukotriene B4 (LTB4)-receptor antagonist attenuated the total MCA and the lowest molecular weight peak of MCA. The concentrations of LTB4 were 153.4 +/- 12.4 (24 h) and 212 +/- 16.6 (72 h) pg/ml. These findings suggest that HLFs may modulate the recruitment of monocytes into the lung by releasing MCP-1, GM-CSF, TGF-beta, and LTB4 constitutively.

Cigarette smoking decreases interleukin-8 secretion by human alveolar macrophages

Cigarette smoking can impair pulmonary immune function, and hence influences the development of lung diseases. Interleukin-8 (IL-8) is a proinflammatory peptide and a potent chemotactic factor for neutrophils, and is produced by both immune and non-immune cells including monocytes and alveolar macrophages (AM). We investigated the effect of cigarette smoking on the secretion of IL-8 by human AM. The IL-8 concentration in bronchoalveolar lavage fluid (BALF) was much higher in smokers than in non-smokers (18.4 +/- 3.9 vs 4.1 +/- 1.0 pg ml-1; P < 0.005). However, spontaneous IL-8 secretion by cultured AM was lower in smokers than in non-smokers (46.8 +/- 12.7 vs 124.1 +/- 24.0 ng ml-1; P < 0.01). When stimulated with lipopolysaccharide (LPS), AM from smokers secreted significantly less IL-8 than those from non-smokers at all tested concentrations of LPS. In contrast, the amount of IL-8 secreted by peripheral blood monocytes with or without LPS stimulation was comparable in smokers and non-smokers. These observations indicate that smoking decreases IL-8 secretion by AM, which may modify or decrease the inflammatory response in the lung.

Heterogeneous expression and release of CD14 by human gingival fibroblasts: characterization and CD14-mediated interleukin-8 secretion in response to lipopolysaccharide

To identify the role in periodontal inflammatory diseases of human gingival fibroblasts (HGF), the major constituents of gingival tissue, the expression of CD14, a possible lipopolysaccharide (LPS) receptor, and the release of soluble CD14 (sCD14) by HGF were examined. Among the HGF samples from the nine donors tested, more than 50% of the HGF from five donors expressed CD14 but less than 20% of HGF from the other four donors did so, as determined by flow cytometric analysis. The CD14 expression on the cell surface was correlated with the expression of CD14 mRNA. The HGF and skin and lung fibroblasts tested expressed no CD18, which indicates that fibroblasts do not possess other LPS receptors, such as CD11b/CD18 and CD11c/CD18. The CD14 expression by the HGF was decreased after subculturing and was highest at the confluent stage of culture. The treatment of high-CD14-expressing (CD14(high)) HGF with phosphatidylinositol-phospholipase C reduced CD14 expression; this result and the increase in a 55-kDa CD14 indicate that the membrane CD14 (mCD14) on the HGF may be a 55-kDa glycosylphosphatidylinositol-anchored protein. CD14(high) HGF spontaneously released 48- and 57-kDa sCD14. The total release of sCD14 by the HGF was augmented by gamma interferon and Escherichia coli LPS in accordance with the increased expression of mCD14. The CD14(high) HGF secreted interleukin-8 in response to LPS, and the secretion was completely inhibited by anti-CD14 antibody. These results suggest that (i) HGF consist of populations that are heterogeneous on the basis of different levels of expression of CD14 and (ii) CD14(high) HGF secrete inflammatory cytokines in response to LPS via CD14.

Involvement of interleukin-8 in dialysis-related arthritis

To elucidate the role of interleukin (IL)-8, a chemotactic factor for neutrophils, in dialysis-related arthritis (DRA) of patients on long-term hemodialysis, the concentration of IL-8 was measured in the synovial fluids of DRA patients with acute arthralgia and joint swelling, and was compared with those in patients with rheumatoid arthritis (RA) and patients with osteoarthritis (OA). We noted a marked elevation of IL-8 in the joint fluids of patients with DRA and RA as compared with OA. Furthermore, to determine the role of IL-8 in synovitis, we examined the in vivo effect of intra-articular injection of human recombinant IL-8 on leukocyte infiltration into the joint space of rabbits. A single injection of IL-8 to the joints of rabbits induced rapid infiltration of neutrophils into the joint space and synovial tissues, which reached a maximum in four hours. The oral administration of indometacin farnesil (a prodrug that is converted to indomethacin after intestinal absorption) before the injection of IL-8 alleviated the infiltration of neutrophils. When human synovial cells were incubated with tumor necrosis factor (TNF)-alpha, the expression of IL-8 mRNA and IL-8 production in the cultured synovial cells were increased. The TNF-alpha-stimulated expression of IL-8 mRNA and IL-8 production in the cultured synovial cells were markedly inhibited by dexamethasone. In conclusion, IL-8 levels were markedly elevated in the joint fluids of patients with DRA. Interleukin-8 released from synovial cells may be an important factor to induce acute inflammation in DRA. Dexamethasone and indomethacin may be effective for DRA by inhibiting the production and chemotactic actions of IL-8, respectively.

Chemokine receptor CXCR4 expression in endothelium

The expression of chemokine receptor and viral coreceptor CXCR4 is reported in cultured endothelial cells and in arterial endothelium. A 1.9 kb transcript was cloned from cultured bovine aortic (BAEC) and human umbilical vein endothelial cells (HUVEC). CXCR4 mRNA was expressed at high levels in BAEC and HUVEC but was not expressed by cultured bovine arterial smooth muscle cells (BASM) or human umbilical vein smooth muscle cells (HUVSM). Western blotting with polyclonal antibodies demonstrated an approximate 46KD protein in endothelial cells only. In situ hybridization and immunocytochemistry (anti-CXCR4 monoclonal antibody 12G5) revealed both transcript and protein expression in cultured endothelial cells, and in the endothelium of normal aorta but not in aortic smooth muscle. The ligand for CXCR4, stromal cell derived factor 1 (SDF-1) stimulated mobilization of intracellular calcium at a moderate level (37% of the peak response to thrombin), confirming the expression of functional receptor at the endothelial surface. The involvement of CXCR4 in chemokine signaling, chemoattraction (through SDF-1), and its potential viral coreceptor activity suggest a multifunctional role in vascular homeostasis and pathophysiology.

Human thyroid fibroblasts exhibit a distinctive phenotype in culture: characteristic ganglioside profile and functional CD40 expression

Fibroblasts from different regions of the human body exhibit substantial phenotypic diversity, some of which relates to the capacity for cross-talk with cells of the immune system. We examine, for the first time, thyroid fibroblast biology in culture. Thyroid explants were placed in culture, and fibroblasts were outgrown and serially passaged. These fibroblasts take on a morphology in culture resembling cells from other anatomic regions. When treated with PGE2, they assume a stellate morphology similar to that of prostanoid-treated orbital fibroblasts. The ganglioside profile exhibited by these cells is distinct from that observed previously in orbital and dermal fibroblasts. They uniformly express Thy-1, a surface glycoprotein. Messenger RNA encoding CD40, a surface receptor found on bone marrow-derived cells, and CD40 protein were expressed constitutively at low levels. Interferon-gamma (500 U/ml) treatment for 48-72 h resulted in high levels of surface HLA-DR and CD40 display. When CD40 is engaged with CD40 ligand (CD40L), nuclear factor-kappaB binding activity is up-regulated as is interleukin (IL)-6 and IL-8 expression. IL-1beta treatment up-regulates the expression of IL-1alpha, IL-1beta, and PGE2. These observations suggest that thyroid fibroblasts possess the molecular machinery necessary for cross-talk with immunocompetent cells such as lymphocytes and mast cells through the CD40/CD40L complex, as well as through classic cytokine networks, and to participate potentially in the inflammatory response of the thyroid gland.

Cell-associated human retinal pigment epithelium interleukin-8 and monocyte chemotactic protein-1: immunochemical and in-situ hybridization analyses

Human retinal pigment epithelial (RPE) cells secrete chemokines, interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) in response to pro-inflammatory cytokines. In this study we (1) examined the efficiency of human RPE IL-8 and MCP-1 secretion, (2) determined the amount of neutrophil and monocyte chemotactic activity in human RPE cell conditioned media and cell extracts that is attributable to IL-8 and MCP-1, respectively, and (3) assessed the sensitivity of immunohistochemistry and in situ hybridization for detecting chemokine production by cytokine-stimulated human RPE cells. Conditioned media and extracts from human RPE cells stimulated with various physiologic concentrations of interleukin-1 beta (IL-1 beta) (0.2-20 ng ml-1), tumor necrosis factor (TNF-alpha) (0.2-20 ng ml-1) or interferon-gamma (IFN-gamma) (10-1000 U ml-1) were examined to compare secreted and cell associated levels of IL-8 and MCP-1 at various time points up to 24 hr. ELISA demonstrated that IL-8 and MCP-1 are both efficiently secreted by pro-inflammatory cytokine treated human RPE cells. Substantial dose- and time-dependent RPE secretion of IL-8 was observed following stimulation with IL-1 beta or TNF-alpha, but cell associated IL-8 was detectable only after high dose (20 ng ml-1) IL-1 beta stimulation and comprised less than 1% of the total IL-8 induced. Dose- and time-dependent RPE cell MCP-1 secretion was also observed following IL-1 beta > TNF-alpha > IFN-gamma stimulation, with an average of 4% of the total MCP-1 retained within RPE. Bioassays demonstrated neutrophil and monocyte chemotactic activity in conditioned media from stimulated RPE cells, but not in human RPE cell extracts. Inhibition of conditioned media-induced chemotaxis by specific anti-IL-8 or anti-MCP-1 antibodies demonstrated that IL-8 and MCP-1 were responsible for the majority of HRPE-derived neutrophil (> 60%) and monocyte (53-57%) chemotactic activity, respectively. Using in situ hybridization IL-8 mRNA was readily detected within IL-1 beta > TNF-alpha stimulated RPE cells and MCP-1 mRNA easily visualized within IL-1 beta > TNF-alpha > or IFN-gamma stimulated cells. Immunohistochemistry to detect IL-8 was positive only in RPE cells exposed to high dose IL-1 beta (20 ng ml-1) for 8 or 24 hr and was weak. Immunohistochemical staining for MCP-1 in RPE cells was more intense and was visualized within RPE cells stimulated with IL-beta, TNF-alpha, or IFN-gamma. This study demonstrates that: (1) RPE cells efficiently secrete IL-8 and MCP-1 upon stimulation with pro-inflammatory cytokines; (2) secreted IL-8 and MCP-1 account for the majority of human RPE neutrophil and monocyte chemotactic activity; (3) in situ hybridization readily detects IL-8 and MCP-1 mRNA in cytokine stimulated RPE cells; and (4) immunohistochemistry demonstrates cell-associated MCP-1 in cytokine stimulated RPE cells, but only minimal cell-associated IL-8.

Interleukin-8 Expression in Human Nasal Polyps

The cytokine Interleukin 8 (IL-8) has been shown to be a potent mediator of leukocyte recruitment and neovascularization in inflammatory and neoplastic diseases. In this study we hypothesize that IL-8 produced in the nasal polyp microenvironment is responsible for the leukocyte recruitment seen in nasal polyposis. To test this hypothesis we evaluated nasal polyps for distribution and content of IL-8 antigen with immunohistochemical techniques and radioimmunoassay to determine tissue levels of IL-8. The immunohistochemical results demonstrated that IL-8 antigen staining occurred predominantly within inflammatory cells and epithelium. IL-8 was detected in all nasal polyp tissue homogenates (a mean value of 1767 ± 1633 pg/mg total protein (TP) with a range of 134 to 3668 pg/mg TP vs control specimens with a mean value of 77 pg/mg TP with a range of 0.09 to 255 pg/mg TP). These data demonstrate the presence and distribution and levels of IL-8 antigen in nasal polyps in vivo, supporting our hypothesis that local production of IL-8 could be an important factor in the sustained recruitment of leukocytes in nasal polyposis. Thus IL-8 likely plays a significant role in the pathogenesis of this disease process and therefore is a potential target for therapeutic intervention.

Induction of interleukin-1 and interleukin-8 mRNAs and proteins by TGF beta 1 in rat lung alveolar epithelial cells

The transforming growth factor-beta (TGF-beta) has been shown to increase in lung injury and in fibrotic states of the lung. In the current study, we sought to investigate whether TGF beta 1 induced the expression of IL-1 alpha and IL-8 in rat alveolar epithelial cells. We evaluated TGF beta 1, IL-1 alpha, and IL-8 expression by immunofluorescence in silica-injured and saline-treated control rat lungs. Antibodies to IL-1 alpha, IL-8, and TGF beta 1 showed intense staining in silica-injured lungs as compared to saline-instilled lungs. Primary isolated type II cells from silica-injured lungs showed increased expression of IL-1 alpha as compared to saline-instilled lungs. To evaluate the effects of TGF beta 1, we treated an immortalized rat type II cell-derived cell line (LM5) with 100 pg/ml of TGF beta 1 in serum-free medium for 0-24 hours and analyzed the expression of IL-1 alpha and IL-8 mRNAs and proteins using semiquantitative RT-PCR, Northern blot analysis, Western blot analysis, and immunohistochemistry. Densitometric analysis of Northern blots showed modest constitutive expression of IL-1 alpha gene in untreated control LM5 cells. TGF beta 1 treatment resulted in an increase in IL-1 alpha mRNA, that reached maximum levels (4-fold) by 2 hours and remained elevated for 4-16 hours, with a subsequent decline by 24 hours. Similarly, Northern blot and RT-PCR analysis demonstrated that TGF beta 1 treatment resulted in maximum induction of IL-8 mRNA (6- 8.5-fold) within 1-4 hours. The levels remained elevated for up to 24 hours afterwards. Western blot analysis results further confirmed the expression of both IL-1 alpha and IL-8 proteins by LM5 cells. TGF beta 1 treatment resulted in increased expression of both IL-1 alpha and IL-8 proteins. Immunofluorescence studies demonstrated increased staining of IL-1 alpha by TGF beta 1 as compared to untreated cells. These results suggest that TGF beta 1 may regulate IL-1 alpha and IL-8 expression in alveolar epithelial cells and contribute to polymorphonuclear leukocyte recruitment and lung injury in clinical states with increased TGF beta 1.

Increased interleukin-8 concentrations in the pulmonary edema fluid of patients with acute respiratory distress syndrome from sepsis

OBJECTIVE

To test the hypothesis that significantly higher concentrations of interleukin-8 (IL-8) are found in the pulmonary edema fluid and plasma of patients with a septic vs. a nonseptic etiology of acute respiratory distress syndrome (ARDS).

DESIGN

Prospective measurement of IL-8 concentrations in previously collected edema fluid and plasma.

SETTING

Adult intensive care units at a university medical center.

PATIENTS

There were 27 patients with ARDS (16 patients with a septic etiology and nine patients with a nonseptic etiology) plus eight control patients with hydrostatic pulmonary edema.

MEASUREMENTS AND MAIN RESULTS

IL-8 was present in the pulmonary edema fluid of all patients with ARDS, but the median IL-8 concentration was higher in the edema fluid of patients with ARDS associated with sepsis (84.2 ng/mL, n = 16) compared with the ARDS patients without sepsis (14.8 ng/mL, n = 11) (p < .05). In patients with cardiogenic edema, IL-8 concentration (5.0 ng/mL,n = 8, p < .05) was significantly lower than those values in patients with ARDS. Median plasma concentration of IL-8 was increased in septic individuals (1.3 ng/mL), but these concentrations were not significantly higher than in patients with a nonseptic etiology of ARDS (0.35 ng/mL) (p = .14) or those patients with cardiac failure (0.21 ng/mL).

CONCLUSIONS

The high concentrations of IL-8 in pulmonary edema fluid, coupled with the relatively low concentrations of IL-8 in the plasma, suggest that the lung was the primary source of IL-8 in the patients with ARDS. The markedly increased concentrations of IL-8 in the pulmonary edema fluid of patients with ARDS from sepsis suggests that this group of patients may be particularly suitable for potential trials directed at inhibiting the activity of this important chemokine.

Interferon-beta prevents the upregulation of interleukin-8 expression in human melanoma cells

The constitutive expression of interleukin-8 (IL-8) by human melanoma cells correlates with their metastatic potential. The exposure of human melanoma cells to the inflammatory cytokines IL-1 beta or tumor necrosis factor-alpha (TNF-alpha) upregulated IL-8 expression in a time-dependent and concentration-dependent manner. This enhanced expression of IL-8 was inhibited by cycloheximide or actinomycin-D. Treatment of melanoma cells with interferon (IFN) alpha, beta, or gamma did not affect the constitutive expression of IL-8, but IFN-alpha and IFN-beta blocked the upregulation of IL-8 expression in cells treated with IL-1 beta or TNF-alpha subsequent to or simultaneously with the IFN. These data suggest that the expression of IL-8 in human melanoma cells can be upregulated by inflammatory cytokines and that IFN-alpha and IFN-beta can counterregulate this stimulation.

Costimulation of fibroblast collagen and transforming growth factor beta1 gene expression by monocyte chemoattractant protein-1 via specific receptors

Recent studies indicate potential roles of monocyte chemotactic protein-1 (MCP-1) in recruitment of monocytes to sites of inflammation. However, their increased expression does not always correlate with monocyte influx, suggesting other possible biological activities for this member of the C-C chemokine family. In view of its potential role in regulating extracellular matrix expression in fibrotic disorders, the effects of MCP-1 on lung fibroblast collagen expression were evaluated. Isolated rat lung fibroblasts were treated with increasing doses of MCP-1 for variable periods of time and examined for effects on collagen synthesis and expression of procollagen alpha1(I) mRNA expression. The results show that MCP-1 was able to stimulate collagen expression in these cells in a dose-dependent manner but required over 24 h for significant elevation to occur. In view of this delayed time course, the possibility of mediation via endogenous transforming growth factor beta (TGFbeta) was tested by the ability of anti-TGFbeta antibody to inhibit this MCP-1 stimulation of collagen expression. Significant but incomplete inhibition by this antibody was observed. Pretreatment of the cells with antisense but not by sense or missense TGFbeta1 oligodeoxyribonucleotides caused essentially complete inhibition of this MCP-1 stimulatory effect. Furthermore, MCP-1 treatment was found to also stimulate TGFbeta secretion and mRNA expression, which was also abolished by pretreatment with antisense TGFbeta1 oligodeoxyribonucleotides. The kinetics of TGFbeta expression indicates that significant increase preceded that for collagen expression. Binding studies using 125I-labeled MCP-1 indicated the presence of specific and saturable binding sites with a dissociation constant consistent with the dose response curves for stimulation of fibroblast collagen synthesis and TGFbeta activity by MCP-1. These results taken together suggest that MCP-1 stimulates fibroblast collagen expression via specific receptors and endogenous up-regulation of TGFbeta expression. The latter then results in autocrine and/or juxtacrine stimulation of collagen gene expression.

Role of interleukin 8 on leucocyte-endothelial cell adhesion in intestinal inflammation

BACKGROUND

An important action of interleukin 8 (IL8) is stimulation of granulocytes. The object of this study was to assess the contribution of IL8 to the leucocyte-endothelial cell interactions associated with intestinal inflammation in the rat.

METHODS

Two indomethacin injections (48 and 24 hours prior to the experiments) induced a longlasting ileitis in rats. The number of adherent and emigrated leucocytes, leucocyte rolling velocity, and shear rate were monitored in normal and inflamed mesenteric postcapillary venules. Some animals received a monoclonal antibody (MAb) against IL8 or CD11b/CD18 at 24 and 12 hours prior to the experiment.

RESULTS

Indomethacin elicited a seven-fold increase in leucocyte adherence and a 5.4-fold increase in leucocyte emigration, while leucocyte rolling velocity was reduced by nearly 80%. The indomethacin induced increases in leucocyte adherence and emigration were significantly reduced (by 57% and 67%, respectively) while leucocyte rolling velocity was increased (to 63% of control) by the IL8-specific MAb. The level of inhibition seen with the IL8 MAb was similar to that associated with administration of a MAb directed against the leucocyte adhesion molecule CD11b/CD18.

CONCLUSIONS

IL8 contributes to the leucocyte-endothelial cell interactions elicited in mesenteric venules by indomethacin.