Molecular cloning of a human monocyte-derived neutrophil chemotactic factor (MDNCF) and the induction of MDNCF mRNA by interleukin 1 and tumor necrosis factor

The expression of chemokine genes correlates with nuclear factor-kappaB activation in human pancreatic cancer cell lines

Chemokines may regulate the process of immune cell infiltration that is often found in pancreatic cancer. In this study, we investigated the secretion of the chemokines [interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, and RANTES (regulated on activation, normal T cell expressed and secreted)] in human pancreatic cancer cell lines. The chemokine secretion in three pancreatic cancer cell lines (PANC-1, MIA PaCa-2, and BxPC-3) was evaluated by enzyme-linked immunosorbent assay (ELISA) and Northern blot, and the activation of nuclear factor-kappaB (NF-kappaB) and NF-IL6 was assessed by an electrophoretic gel mobility shift assay (EMSA). Without any stimulation, IL-8 secretion was detected in all cell lines, and MCP-1 secretion was detected in PANC-1 and MIA PaCa-2 cells. However, RANTES secretion was not detected in all cells. The addition of IL-1beta and tumor necrosis factor (TNF)-alpha strongly enhanced IL-8, MCP-1, and RANTES secretion; these responses were observed at the mRNA level as well as at the protein level. IL-1beta and TNF-alpha induced a rapid activation of nuclear factor (NF)-kappaB in PANC-1 cells, and the increase in chemokine mRNA expression correlated with NF-kappaB activation. The activation of NF-IL6 was modest. A blockade of NF-kappaB activation by TPCK markedly reduced the IL-1beta- and TNF-alpha-induced chemokine gene expression. Our findings indicate that chemokines are produced by pancreatic cancer cells, and suggest that these factors may contribute to the accumulation of tumor-associated immune cells. In addition, the transcriptional activation of chemokine genes in pancreatic cancer cells may be closely associated with NF-kappaB activation.

Activation of transcription factors NF-kappaB and NF-IL-6 by human immunodeficiency virus type 1 protein R (Vpr) induces interleukin-8 expression

Human immunodeficiency virus (HIV)-positive individuals express elevated levels of interleukin-8 (IL-8), which is believed to be responsible for some of the clinical manifestations occurring during AIDS. We report here that virion-derived HIV type 1 (HIV-1) protein R (Vpr) increased IL-8 expression in primary T cells and macrophages, as well as in the T-cell line Jurkat, the monocytic cell line U937, and the epithelial cell line A549. Vpr appeared to increase IL-8 expression and IL-8 promoter activity by activating transcription factors NF-kappaB and NF-IL-6. Elevated Vpr was also shown to increase transcription of the NF-kappaB and NF-IL-6 enhancer-containing viral promoters for HIV, cytomegalovirus, and simian virus 40, as well as increase the expression of IL-6 and IL-10 in primary macrophages and in A549 cells, tumor necrosis factor alpha expression in primary T cells, and IL-6 and gamma interferon expression in U937 cells. These results suggest a new role for Vpr in the pathogenesis of HIV infection, namely, the activation of transcription factors NF-IL-6 and NF-kappaB.

Effects of human IL-8 isoforms on bovine neutrophil function in vitro

Interleukin 8 (IL-8) is a potent chemotactic and activating agent for human neutrophils and bovine IL-8 is chemotactic for bovine neutrophils; however, it is unclear whether IL-8 activates bovine neutrophils. Two isoforms of human recombinant (hr) IL-8 protein (77 and 72 amino acid) were used to stimulate bovine neutrophils in vitro. Bovine neutrophils exhibited significant migration in the presence of 0.1, 0.5, 1.0 and 5.0ngml(-1) hr IL-8 when incubated for 30min at 37 degrees C in a modified Boyden chamber assay. Both the 77 and 72 aa forms were equally effective in inducing migration in this assay. At the highest doses of IL-8 examined (1 and 5ngml(-1)), migration was similar to migration in the presence of 20% zymosan-activated serum (ZAS) or 12h lipopolysaccharide (LPS)-stimulated blood monocyte supernatants (CM). Significant (p<0. 05) release of alkaline phosphatase (ALK-P) (from specific granules) occurred but myeloperoxidase (MPO) release and superoxide anion production were not enhanced in bovine neutrophils by either form of hrIL-8 at any of the doses tested. Significant (p<0.05) alkaline phosphatase release was observed in the presence of 10 and 100ngml(-1) for the 72 aa form of IL-8 and only at the higher dose for the 77 aa form of IL-8. The ZAS and CM significantly enhanced neutrophil degranulation of ALK-P and MPO as well as inducing superoxide anion production. These results suggest that IL-8 may play a role in both neutrophil recruitment and activation during bovine inflammatory processes.

Calcitonin gene-related peptide induces IL-8 synthesis in human corneal epithelial cells

Calcitonin gene-related peptide (CGRP), a neuropeptide with proinflammatory activities, is released from termini of corneal sensory neurons in response to pain stimuli. Because neutrophil infiltration of the clear corneal surface is a hallmark of corneal inflammation in the human eye, we determined whether CGRP can bind to human corneal epithelial cells (HCEC) and induce expression of the neutrophil chemotactic protein IL-8. It was found that HCEC specifically bound CGRP in a saturable manner with a Kd of 2.0 x 10-9 M. Exposure of HCEC to CGRP induced a significant increase in intracellular cAMP levels and enhanced IL-8 synthesis nearly 4-fold. The capacity of CGRP to stimulate cAMP and IL-8 synthesis was abrogated in the presence of the CGRP receptor antagonist CGRP8-37. CGRP stimulation had no effect on the half-life of IL-8 mRNA while increasing IL-8 pre-mRNA synthesis >2-fold. In contrast to IL-8, CGRP did not induce monocyte chemotactic protein-1 or RANTES synthesis, nor did the neuropeptide enhance detectable increases in steady state levels of mRNA specific for these two beta-chemokines. The results suggest that HCEC possess CGRP receptors capable of initiating a signal transduction cascade that differentially activates expression of the IL-8 gene but not the genes for monocyte chemotactic protein-1 or RANTES. The capacity of CGRP to stimulate IL-8 synthesis in HCEC suggests that sensory neurons are involved in induction of acute inflammation at the eye surface.

Reactive nitrogen and oxygen species attenuate interleukin- 8-induced neutrophil chemotactic activity in vitro

Peroxynitrite, formed by the reaction between nitric oxide and superoxide, has been shown to induce protein nitration, which compromises protein function. We hypothesized that peroxynitrite may regulate cytokine function during inflammation. To test this hypothesis, the neutrophil chemotactic activity (NCA) of interleukin-8 (IL-8) incubated with peroxynitrite was evaluated. Peroxynitrite attenuated IL-8 NCA in a dose-dependent manner (p < 0.01) but did not significantly reduce NCA induced by leukotriene B(4) or complement-activated serum. The reducing agents, dithionite, deferoxamine, and dithiothreitol, reversed and exogenous L-tyrosine abrogated the peroxynitrite-induced NCA inhibition. Papa-NONOate [N-(3-ammoniopropyl)-N-(n-propyl)amino]diazen-1-ium-1, 2-dialase or sodium nitroprusside, NO donors, or a combination of xanthine and xanthine oxidase to generate superoxide did not show an inhibitory effect on NCA induced by IL-8. In contrast, small amounts of SIN-1, a peroxynitrite generator, caused a concentration-dependent inhibition of NCA by IL-8. Consistent with its capacity to reduce NCA, peroxynitrite treatment reduced IL-8 binding to neutrophils. Nitrotyrosine was detected in the IL-8 incubated with peroxynitrite by enzyme-linked immunosorbent assay. These findings are consistent with nitration of tyrosine by peroxynitrite with subsequent inhibition of IL-8 binding to neutrophils and a reduction in NCA and suggest that oxidants may play an important role in regulation of IL-8-induced neutrophil chemotaxis.

Interleukin-8 overexpression is present in pyoderma gangrenosum ulcers and leads to ulcer formation in human skin xenografts

Interleukin-8 (IL-8) is a potent chemotactic polypeptide for neutrophils. However, the role of this cytokine during inflammation remains unclear. Skin specimens from patients with pyoderma gangrenosum demonstrated IL-8 overexpression in skin ulcers, which suggests a role for IL-8 in the development of the disease. We therefore constructed a recombinant adenovirus expressing the complementary deoxyribonucleic acid encoding human IL-8 (IL-8/Ad5) that induces a 2000-fold increase in IL-8 expression of infected human fibroblasts in vitro. Human skin engrafted to severe combined immunodeficiency mice and then injected with the recombinant virus demonstrated erythema, an intense perivascular infiltration of neutrophils, and extravasation of erythrocytes after 8 hours. By 12 hours after injection, neutrophils had accumulated beneath the epidermis, which then necrotized, and one or more ulcers that remained for approximately 2 weeks were observed. Clinically and histologically, the ulcers resembled pyoderma gangrenosum. These clinical and experimental findings suggest an etiologic role of IL-8 in the pathogenesis of pyoderma gangrenosum.

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.

Pharmacologic doses of interleukin 8 suppositories induce follicular maturation in rabbits

Interleukin 8 (IL-8) is a neutrophil chemoattractant/activating factor that plays a role in the ovarian physiology leads to investigate the effects of IL-8 on follicular maturation. Experiments were conducted using suppositories containing 100 ng, 200 ng, 400 ng IL-8, 500 microl Witepsol-base (control), human menopausal gonadotropin (im) and conjugate of fluorescein isithiocyanate-labelled IL-8. The levels of IL-8 in ovarian fluid were also measured. Histology of ovaries treated with 200 ng IL-8 showed large antral follicles filled with follicular fluid. The theca layer was divided into an interna and an externa with large extracellular spaces. The granulosa cells were loosened and appeared to be detaching from the granulosa layer. Neutrophils were localized predominantly in the theca and medulla (P<0.0001, P<0.004), and relative collagen concentration was significantly decreased in ovaries of 200 ng IL-8 (P<0.0001) compared with controls. The IL-8 was detected in ovarian fluid after 6 h (P<0.0001), 12 h (P<0.001), and 18 h (P<0.01) compared with 0 h. Fluorescein isithiocyanate-labelled IL-8 conjugate was seen in the follicular wall and endometrium. We conclude that pharmacological dosage of exogenous IL-8 exerts an effect on follicular maturation through granulocyte chemotaxis and activation.

Cadmium-induced acute hepatic injury is exacerbated in human interleukin-8 transgenic mice

It is reported repeatedly that severe hepatocellular necrosis along with infiltration of neutrophils occurs after acute cadmium exposure. Neutrophils, which migrate by the gradient of chemoattractants such as interleukin-8, are believed to play an important role in inflammation at the damaged sites. To investigate whether neutrophils aggravate or repair the liver injury induced by cadmium, we checked the hepatotoxic effects of cadmium on human interleukin-8 transgenic mice (hIL-8Tg), which overexpressed IL-8 and displayed an inability of neutrophil migration resulting from both the lack of chemotactic gradient and the downregulation of l-selectin on the surface of neutrophils. A significantly lower survival rate was observed in hIL-8Tg compared with wild-type mice after subcutaneous administration of cadmium. Evident liver injury characterized by abrupt increases in plasma GOT and GPT levels was found in hIL-8Tg at 18 h after cadmium administration. Histological examinations, including H & E staining and esterase staining, revealed the infiltration of numerous neutrophils into the damaged liver tissues in wild-type mice, and the inhibition of the neutrophil migration into the liver as well as enhanced hepatocellular necrosis in hIL-8Tg. Peripheral white blood cell and polymorphonuclear cell counts increased and reached their peaks at 12 h after cadmium administration in wild-type mice, whereas the increase in blood leukocyte counts was delayed in hIL-8Tg. There was no significant difference in the amounts of cadmium accumulated in liver and kidneys between wild-type mice and hIL-8Tg. In conclusion, an acute cadmium hepatotoxic effect was exacerbated in hIL-8Tg resulting from inhibited neutrophil migration, suggesting that migrated neutrophils can prevent aggravation of liver injury by acute cadmium administration.

Transforming growth factor-beta1 acts as a potent inhibitor of complement C3 biosynthesis in human pancreatic cancer cell lines

In this study, we attempted to determine how transforming growth factor (TGF)-beta1 affects complement C3 secretion in the pancreatic cancer cell lines PANC-1 and BxPC-3. We also compared the responses in C3 secretion with those in interleukin (IL)-8 secretion. The C3 and IL-8 expression was evaluated at the protein and messenger RNA (mRNA) levels. The activation of nuclear factor-kappaB (NF-kappaB) was assessed by an electrophoretic gel mobility shift assay (EMSA). IL-1beta and tumor necrosis factor (TNF)-alpha both induced a marked increase in C3 and IL-8 secretion. However, TGF-beta1 potently decreased the IL-1beta- and TNF-alpha-induced C3 secretion, whereas the IL-8 secretion was weakly but significantly enhanced. These responses were also observed at the mRNA level. In PANC-1 cells, IL-1beta and TNF-alpha induced a rapid activation of nuclear factor (NF)-kappaB, and TGF-beta1 enhanced this activation slightly. The induction of Fos protein has been reported to be required for the inhibitory action of TGF-beta1, and the translocation of Fos protein into the nucleus was associated with TGF-beta1 stimulation in PANC-1 cells. Our results suggest that TGF-beta1 may act as a potent inhibitor of C3 secretion in pancreatic cancer cell lines under inflammatory conditions. This action of TGF-beta1 did not correlate with NF-kappaB activation, but associated with the translocation of Fos protein into the nucleus.

Level of interleukin-8 expression by metastatic human melanoma cells directly correlates with constitutive NF-kappaB activity

The purpose of this study was to determine whether constitutive NF-kappaB activity regulates the expression level of interleukin-8 (IL-8) in metastatic human melanoma cells. Cultures of metastatic human A375 melanoma cells expressed higher levels of IL-8 mRNA and protein than nonmetastatic A375 human melanoma cells. No discernible differences in IL-8 half-life were found between metastatic and nonmetastatic cells, but cells that overexpressed IL-8 had a higher transcription rate and increased IL-8 promoter activity. Analysis of the IL-8 promoter using deletion mutants revealed that the region within -133 was essential for constitutive IL-8 promoter activity and that mutation of NF-kappaB binding sites eliminated the constitutive IL-8 promoter activity. The activation of constitutive IL-8 transcription directly correlated with the level of constitutive NF-kappaB activity. Transfection of melanoma cells with a dominant-negative mutant IkappaBalpha expression vector (pLXSN-IkappaBalphaM) significantly decreased the level of constitutive NF-kappaB activity and expression of IL-8, demonstrating that constitutive NF-kappaB/relA activities contribute to overexpression of IL-8 in highly metastatic human melanoma cells.

Interleukin-8 gene repression by clarithromycin is mediated by the activator protein-1 binding site in human bronchial epithelial cells

Macrolide antibiotics are known to be effective for the treatment of chronic inflammatory airway diseases including diffuse panbronchiolitis, chronic bronchitis, and bronchial asthma. Other than having antimicrobial activities, macrolides have antiinflammatory effects, such as the inhibition of cytokine production. In the present study we investigated the effects of clarithromycin (CAM) on interleukin (IL)-8 gene expression and protein levels, using the human bronchial epithelial cell line BET-1A. Northern blot analyses showed that CAM inhibited tumor necrosis factor (TNF)-alpha-induced IL-8 gene expression in a dose- and incubation time-dependent manner. The half-life of IL-8 messenger RNA transcripts in TNF-alpha-treated BET-1A cells did not change with CAM. Transfection studies with BET-1A cells, using fusion genes composed of the 5'-flanking sequences of the IL-8 gene and a luciferase reporter gene, demonstrated potent promoter activity in a 174-bp segment (-130 to +44 bp relative to the transcription start site). This segment includes activator protein (AP)-1 and nuclear factor (NF)-kappaB-like sites, and exhibited its strongest response to TNF-alpha. TNF-alpha-induced promoter activity in this segment showed a significant repression by CAM. However, a 156-bp segment (-112 to +44 bp) that does not include an AP-1 site but includes an NF-kappaB-like site did not show a significant repression of TNF-alpha-induced promoter activity by CAM. Mutation of the AP-1 binding site abrogated the suppression by CAM of TNF-alpha-induced enhancement of luciferase activity. In accord with promoter analyses, an electrophoretic mobility shift assay showed that CAM repressed AP-1 binding in TNF-alpha-treated BET-1A cells; however, TNF-alpha induced both AP-1 and NF-kappaB binding activities in BET-1A cells. These data suggest that macrolides such as CAM repress IL-8 gene transcription mainly via the AP-1 binding site in human bronchial epithelial cells. Our findings provide a novel mechanism for the antiinflammatory function of macrolides, implicating a target for the development of new drugs for treating chronic airway inflammation.

Cetirizine counter-regulates interleukin-8 release from human epithelial cells (A549)

BACKGROUND

Cetirizine, a H1-receptor antagonist, exerts besides its well-known anti-allergic potential an array of anti-inflammatory activities. In particular epithelial cells activated in the presence of cetirizine showed a reduced ICAM-1 cell surface expression and a diminished release of sICAM-1.

OBJECTIVE

We wondered whether cetirizine might influence the release of interleukin-8 (IL-8) from human epithelial cells activated with agonists distinct from histamine.

METHODS

We used the human lung epithelial cell line A549 for our in vitro studies. IL-8 release was determined by IL-8 enzyme immunoassay, the intracellular staining for IL-8 and NF-kB was analysed by FACS analysis and IL-8 mRNA steady state level was studied by Northern blot analysis. Confluent epithelial cell monolayer were pre-incubated with cetirizine (0.01 -1.0 micromol/L) for 30 min and afterwards activated with pro-inflammatory cytokines (TNF-alpha IL-1beta, IL-6, IFN-gamma) or different agonists (PMA, NaF, respiratory syncytial virus [RSV]) for 24 h.

RESULTS

Epithelial cells stimulated with TNF-alpha IL-1beta, PMA and RSV, respectively, showed a significantly increased release of IL-8. Pre-incubation with cetirizine diminished the IL-8 release from cells activated with TNF-alpha or PMA in a significant manner. The reduced IL-8 release coincided with a diminished percentage of cells expressing IL-8. Northern blot analysis revealed a reduced steady state level of IL-8 mRNA in cells pretreated with cetirizine and stimulated with TNF-alpha. Furthermore, a decreased amount of accessible DNA-binding sites of the nuclear factor kappa B (NF-kB) was determined by FACS analysis.

CONCLUSIONS

These results suggest that cetirizine reduced the release of IL-8 from A549 cells stimulated with PMA and TNF-alpha, respectively, by lowering IL-8 gene expression. Therefore, cetirizine might exert anti-inflammatory effects beyond its H1-receptor antagonistic activity in the course of inflammatory respiratory tract disorders such as bronchial asthma and allergic rhinitis.

Plasma IL-8 and IL-6 levels can be used to define a group with low risk of septicaemia among cancer patients with fever and neutropenia

The standard therapy for patients with fever and chemotherapy-related neutropenia is hospitalization and infusion of broad-spectrum antibiotics. Early discharge of a defined group of patients at low risk for septicaemia would be of great advantage for these patients. In this study plasma interleukin-8 (IL-8) and interleukin-6 (IL-6) levels measured at start of fever (n = 72) could define a low-risk group of febrile patients with neutropenia due to chemotherapy. For this purpose we collected and analysed data on 72 fever episodes from 53 patients with chemotherapy-related neutropenia, aged between 1 and 66 years. Of the 72 episodes, 18 were classified as bacteraemia and/or clinical sepsis (sepsis group). The IL-6 and IL-8 plasma concentration were significantly increased in patients with chemotherapy-related neutropenia and fever due to bacteraemia versus fever of non-bacterial origin (P = 0.043 and P = 0.022 respectively). Logistic regression analysis, with sepsis as the outcome variable, revealed significant effects of age combined with either IL-6 or IL-8. Sepsis occurrence was lowest for patients <16 years and highest in patients between 16 and 50 years, and was higher in patients with increased IL-6 (P = 0.032) or IL-8 (P = 0.049). No significant effect of leucocyte count, C-reactive protein, sex or underlying malignancy at presentation was detected. The plasma IL-6 and IL-8 levels were fairly strongly correlated (Pearson r = 0.62). Using a cut-off value with 100% sensitivity, both IL-8 and IL-6 could define a low-risk group of neutropenic patients of 28% (CI 15-40%) at the start of the febrile period. Intervention studies are warranted to confirm this result and to investigate whether an early discharge based on IL-8 or IL-6 measurement is safe, increases the quality of life, and results in cost savings.

Counter-regulatory effect of sodium butyrate on tumour necrosis factor-alpha (TNF-alpha)-induced complement C3 and factor B biosynthesis in human intestinal epithelial cells

The various biological activities of butyrate have been well documented. In this study, we tested the effects of butyrate on TNF-alpha-induced complement C3 and factor B biosynthesis in human intestinal epithelial cells. The biosynthesis of C3, factor B and IL-8 was evaluated at the protein and mRNA levels. To evaluate transcriptional activation, the nuclear run-on assay was performed. The transcription factor-DNA binding activity was assessed by an electrophoretic gel mobility shift assay (EMSA). In the intestinal epithelial cell lines HT-29, T84 and Caco-2, sodium butyrate enhanced TNF-alpha-induced C3 secretion, but suppressed TNF-alpha-induced factor B and IL-8 secretion. Nuclear run-on assay revealed that transcriptional regulatory mechanisms are involved in the effects of sodium butyrate. The EMSAs indicated that sodium butyrate suppressed TNF-alpha-induced nuclear factor (NF)-kappaB- and activation protein (AP)-1-DNA binding activity, but enhanced TNF-alpha-induced activation of CCAAT/enhancer-binding protein (C/EBP)beta (NF-IL-6)-DNA binding activity. Sodium butyrate induced a counter-regulatory effect on TNF-alpha-induced C3 and factor B biosynthesis in human intestinal epithelial cells. Butyrate action has been discussed with its activity to induce histone hyperacetylation, but its counter-regulatory effect on complement biosynthesis may be closely associated with the modulation of transcription factor activation.

Transfection of interleukin-8 increases angiogenesis and tumorigenesis of human gastric carcinoma cells in nude mice

The growth and spread of tumour cells depends on adequate vasculature. We have previously reported that the expression of interleukin-8 (IL-8) directly correlates with the vascularity of human gastric carcinomas. To provide evidence for a causal role of IL-8 in angiogenesis and tumorigenicity of human gastric cancer, we used the lipofectin method to stably transfect the human TMK-1 gastric carcinoma cells (low endogenous IL-8) with an IL-8 expression vector or control vector. Transfection with IL-8 did not affect the proliferation of cultured cells, yet the culture supernatants of the transfected (but not control) cells stimulated proliferation of human umbilical vein endothelial cells. The IL-8-transfected and control cells were injected into the gastric wall of nude mice. IL-8-transfected cells produced rapidly growing, highly vascular neoplasms as compared to control cells. These results provide direct evidence for the role of IL-8 in the angiogenesis and tumorigenicity of human gastric carcinomas.

Compartmentalization of the inflammatory response to inhaled grain dust

Interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha, and the secreted form of the IL-1 receptor antagonist (sIL-1RA) are involved in the inflammatory response to inhaled grain dust. Previously, we found considerable production of these cytokines in the lower respiratory tract of workers exposed by inhalation to aqueous extracts of corn dust extract. Alveolar macrophages (AM) have long been considered the cell type responsible for producing these cytokines, and only recently has it been realized that airway epithelial cells may also be involved in cytokine production. In order to determine whether airway epithelia are involved in the inflammatory response to inhaled corn dust extract and to compare the magnitude of response of bronchial epithelial cells (BE) and bronchoalveolar lavage (BAL) cells, we used the reverse transcriptase/polymerase chain reaction (RT/PCR) technique in a semiquantitative manner to evaluate the concentration of IL-1beta, IL-6, IL-8, TNF-alpha, and sIL-1RA. Alveolar cells were obtained by BAL, and BE were obtained by endobronchial brush biopsy from 15 grain handlers 6 h after experimental inhalation of saline or an aqueous corn dust extract. After inhalation of saline, BE expressed low but detectable levels of IL-6, IL-8, and IL-1beta (> 1 complementary DNA [cDNA] molecule/cell). After inhalation of corn dust extract, the expression of messenger RNA (mRNA) for IL-1beta and IL-8 in the BE were significantly increased, whereas no change was seen in IL-6, sIL-1RA, and TNF-alpha mRNA expression. Comparing cytokine mRNA levels in BE and BAL cells from the same subjects after inhalation of corn dust extract, BE and BAL cells expressed equivalent amounts of IL-8 mRNA; IL-1beta was 11-fold higher in BAL cells; and TNF-alpha and sIL-1RA were expressed exclusively by BAL cells. Immunostaining for the cytokines in BAL cells showed cytokine protein expression in AMs but not in polymorphonuclear cells (PMNs). On the other hand, sIL-1RA was strongly expressed in both AMs and PMNs. Analysis of cytokine protein levels in endobronchial lavage (EBL) fluid demonstrated that only IL-8 was released in detectable amounts into the airway lumen, whereas all the other cytokines of interest were exclusively found in the BAL fluid. Thus, within 6 h after inhalation exposure to corn dust extract, BE appear to contribute to airway inflammation by producing IL-8. AMs are responsible for most of the IL-1beta and IL-6 production in the alveolar region, whereas AMs and PMNs both produce sIL-1RA. Our findings suggest that the inflammatory response to inhaled grain dust is compartmentalized, involving specific mediators of inflammation released by macrophages, neutrophils, and airway epithelial cells.

Chemokines and allergic disease

Understanding the chemokine network has become one of the great challenges for researchers interested in inflammatory mechanisms and inflammation-based diseases. The complexity and diversity of the system provide not only a daunting task for its comprehension but also numerous opportunities for development of new, targeted therapies. It is now certain that chemokines are involved as important mediators of allergic inflammation; the fine details and scope of their roles are now under investigation. Presumably, because of distinct pressures on the immune systems of people living in different geographic regions, genetic variation of ligands, receptors, and regulatory regions in the network have emerged. Establishing the roles of these polymorphisms in determining disease susceptibility or progression among individuals and in distinct ethnic groups will provide a basis for improved understanding and treatment of allergic diseases.

Nuclear Factor-κB–Dependent Induction of Interleukin-8 Gene Expression by Tumor Necrosis Factor : Evidence for an Antioxidant Sensitive Activating Pathway Distinct From Nuclear Translocation

Tumor necrosis factor  (TNF) is a pluripotent activator of inflammation by inducing a proinflammatory cytokine cascade. This phenomenon is mediated, in part, through inducible expression of the CXC chemokine, interleukin-8 (IL-8). In this study, we investigate the role of TNF-inducible reactive oxygen species (ROS) in IL-8 expression by “monocyte-like” U937 histiocytic lymphoma cells. TNF is a rapid activator of IL-8 gene expression by U937, producing a 50-fold induction of mRNA within 1 hour of treatment. In gene transfection assays, the effect of TNF requires the presence of an inducible nuclear factor-κB (NF-κB) (Rel A) binding site in the IL-8 promoter. TNF treatment induces a rapid translocation of the 65 kD transcriptional activator NF-κB subunit, Rel A, whose binding in the nucleus occurs before changes in intracellular ROS. Pretreatment (or up to 15 minutes posttreatment) relative to TNF with the antioxidant dimethyl sulfoxide (DMSO) (2% [vol/vol]) blocks 80% of NF-κB–dependent transcription. Surprisingly, however, DMSO has no effect on inducible Rel A binding. Similar selective effects on NF-κB transcription are seen with the unrelated antioxidants, N-acetylcysteine (NAC) and vitamin C. These data indicate that TNF induces a delayed ROS-dependent signalling pathway that is required for NF-κB transcriptional activation and is separable from that required for its nuclear translocation. Further definition of this pathway will yield new insights into inflammation initiated by TNF signalling.

Nuclear Factor-κB–Dependent Induction of Interleukin-8 Gene Expression by Tumor Necrosis Factor : Evidence for an Antioxidant Sensitive Activating Pathway Distinct From Nuclear Translocation

Tumor necrosis factor  (TNF) is a pluripotent activator of inflammation by inducing a proinflammatory cytokine cascade. This phenomenon is mediated, in part, through inducible expression of the CXC chemokine, interleukin-8 (IL-8). In this study, we investigate the role of TNF-inducible reactive oxygen species (ROS) in IL-8 expression by “monocyte-like” U937 histiocytic lymphoma cells. TNF is a rapid activator of IL-8 gene expression by U937, producing a 50-fold induction of mRNA within 1 hour of treatment. In gene transfection assays, the effect of TNF requires the presence of an inducible nuclear factor-κB (NF-κB) (Rel A) binding site in the IL-8 promoter. TNF treatment induces a rapid translocation of the 65 kD transcriptional activator NF-κB subunit, Rel A, whose binding in the nucleus occurs before changes in intracellular ROS. Pretreatment (or up to 15 minutes posttreatment) relative to TNF with the antioxidant dimethyl sulfoxide (DMSO) (2% [vol/vol]) blocks 80% of NF-κB–dependent transcription. Surprisingly, however, DMSO has no effect on inducible Rel A binding. Similar selective effects on NF-κB transcription are seen with the unrelated antioxidants, N-acetylcysteine (NAC) and vitamin C. These data indicate that TNF induces a delayed ROS-dependent signalling pathway that is required for NF-κB transcriptional activation and is separable from that required for its nuclear translocation. Further definition of this pathway will yield new insights into inflammation initiated by TNF signalling.

Chemokine responses and accumulation of inflammatory cells in the lungs of mice infected with highly virulent Cryptococcus neoformans: effects of interleukin-12

We examined the mechanisms involved in the development of lung lesions after infection with Cryptococcus neoformans by comparing the histopathological findings and chemokine responses in the lungs of mice infected with C. neoformans and assessed the effect of interleukin (IL) 12 which protects mice from lethal infection. In mice infected intratracheally with a highly virulent strain of C. neoformans, the yeast cells multiplied quickly in the alveolar spaces but only a poor cellular inflammatory response was observed throughout the course of infection. Very little or no production of chemokines, including MCP-1, RANTES, MIP-1alpha, MIP-1beta and IP-10, was detected at the mRNA level using RT-PCR as well as at a protein level in MCP-1, RANTES and MIP-1alpha. In contrast, intraperitoneal administration of IL-12 induced the synthesis of these chemokines and a marked cellular inflammatory response involving histiocytes and lymphocytes in infected mice. Our findings were confirmed by flow cytometry of intraparenchymal leukocytes obtained from lung homogenates which showed IL-12-induced accumulation of inflammatory cells consisting mostly of macrophages and CD4+ alphabeta T cells. On the other hand, C-X-C chemokines including MIP-2 and KC, which attract neutrophils, were produced in infected and PBS-treated mice but treatment with IL-12 showed a marginal effect on their level, and neutrophil accumulation was similar in PBS- and IL-12-treated mice infected with C. neoforman. Our results demonstrate a close correlation between chemokine levels and development of lung lesions, and suggest that the induction of chemokine synthesis may be one of the mechanisms of IL-12-induced protection against cryptococcal infection.

Interleukin-8 release from human gestational tissue explants: effects of gestation, labor, and chorioamnionitis

Interleukin-8 (IL-8) is a chemotactic cytokine that has been implicated in the process of human parturition, including the processes of cervical ripening and rupture of fetal membranes. In this study, the in vitro release of IL-8 from human amnion, choriodecidua, and placenta tissues obtained before and after spontaneous labor onset both at term and preterm, was assessed. The effect of chorioamnionitis on IL-8 release was also established. All tissue explants examined released IL-8; however, IL-8 release from choriodecidual explants was significantly (p < 0.02) greater than that observed from amnion and placenta. Furthermore, choriodecidual IL-8 release was significantly (p < 0.001) greater from term tissues (850 +/- 134.4 ng/mg DNA, n = 18) than from preterm tissues (458 +/- 68.8 ng/mg DNA, n = 17). Spontaneous onset of labor, irrespective of the eventual mode of delivery, was not associated with any significant changes in IL-8 release from human gestational tissues compared to not-in-labor tissues, both at term and preterm. IL-8 release from gestational tissues was not significantly different in the absence or presence of chorioamnionitis. These data are in contrast to the previously reported stimulatory effects of bacterial endotoxin on IL-8 release from human gestational tissues. The data are consistent, however, with the suggestion that IL-8 release is an early event in chorioamnionitis that precedes the appearance of clinically overt symptoms.

Human placental cells show enhanced production of interleukin (IL)-8 in response to lipopolysaccharide (LPS), IL-1 and tumour necrosis factor (TNF)-alpha, but not to IL-6

Interleukin-8 (IL-8) is a chemotactic and activating factor for neutrophils which play important roles in host defence mechanisms. The human placenta constitutively produces IL-8 during pregnancy and enhances its production in chorioamnionitis. The present study was designed to investigate in vitro the regulatory mechanism for IL-8 production in the placentas in normal and inflammatory states. Placental cells produced IL-8 in a dose-dependent fashion when stimulated with lipopolysaccharide (LPS). The purified trophoblasts showed significantly higher IL-8 production than untreated placental cells. The expression of IL-8 gene in the trophoblasts in the third trimester was observed by reverse transcription-polymerase chain reaction (RT-PCR). The placental cells also release IL-8 in a dose-dependent manner, in response to r-(recombinant) IL-1alpha and tumour necrosis factor (TNF)-alpha, but not rIL-6. Moreover, LPS-activated placental cells spontaneously produced a much larger amount of IL-8 and showed increased responses to rIL-1alpha and TNF-alpha. It may, therefore, be proposed that placental cells with multiple endocrine functions exert immunological functions by constitutive production of IL-1 and TNF-alpha, which stimulate placental IL-8 release. This cytokine cascade in the placenta may be augmented by LPS in chorioamnionitis, thereby potentiating the feto-maternal defence mechanisms against infection.

Airway epithelial cell-induced activation of monocytes and eosinophils in respiratory syncytial viral infection

The early inflammatory events in respiratory syncytial viral (RSV) infection are likely to be crucial in the development of clinical disease, which is characterized by bronchiolitis with mononuclear cell inflammation, some eosinophil involvement and airway hyperreactivity. Since RSV replication is restricted to airway epithelial cells, our working hypothesis is that inflammatory cell recruitment by the infected cells will set the stage for late immunopathology. We have identified the selective induction and release of mononuclear cell and eosinophil-attracting beta-chemokines MIP-1alpha and RANTES, but not eotaxin, by RSV-infected airway epithelial cells and herein demonstrated the recruitment of eosinophils and monocytes, but not neutrophils, in response to chemokines produced by infected epithelial cells during viral replication and dissemination. The chemotactic response of both eosinophils and monocytes was inhibited by antibodies to RANTES but not to MIP-1alpha. Interaction of eosinophils or monocytes with RSV-infected epithelial cells resulted in the production of additional beta-chemokines MCP-1 and MIP-1beta, and increased levels of MIP-1alpha. The monocyte containing cultures produced >10 fold the amount of these chemokines compared to eosinophil containing cultures. On the other hand, the levels of RANTES and the lack of eotaxin were not altered in the cocultures, RSV-infected monocytes appeared to be the main source of MIP-1alpha and MIP-1beta, while MCP-1 was derived from monocytes as well as epithelial cells following coculture. These data implicate RANTES as the primary chemokine responsible for selectively recruiting eosinophils and monocytes to the site of RSV infection. This inflammatory response results in the production of high levels of additional chemokines capable of setting up a full-fledged inflammatory response including lymphocytes.

Induction of interleukin 8 (IL-8) production by Pseudomonas nitrite reductase in human alveolar macrophages and epithelial cells

Interleukin-8 (IL-8) participates in the generation of dense neutrophil accumulations in bronchopulmonary infections caused by Pseudomonas aeruginosa (P. aeruginosa). We have recently reported that nitrite reductase, a bifunctional enzyme located in the periplasmic space of P. aeruginosa, induces IL-8 generation in bronchial epithelial cells (K. Oishi et al. Infect. Immun. 65: 2648-2655, 1997). We examined whether or not Pseudomonas nitrite reductase (PNR) could also stimulate human alveolar macrophages (AM) and pulmonary type II epithelial-like cells (A549) to induce IL-8 production and mRNA expression as well as the production of TNF alpha and IL-1beta. We demonstrated a time- and dose-dependent IL-8 protein synthesis and IL-8 mRNA expression, but no TNF alpha or IL-1beta production, by A549 cells in response to PNR. New protein translation was not required for PNR-mediated IL-8 mRNA expression in the same cells. Furthermore, simultaneous stimulation of PNR with serial doses of TNF alpha or IL-1beta resulted in additive IL-8 production in A549 cells. In adherent AM, PNR enhanced IL-8 protein synthesis and IL-8 mRNA expression in a time-dependent fashion. PNR similarly induced a time-dependent production of TNF alpha and IL-1beta by human adherent AM. Neutralization of TNF alpha or IL-1beta did not influence the levels of IL-8 production in adherent AM culture. We also evaluated whether the culture supernatants of the A549 cells or AM stimulated with PNR could similarly mediate neutrophil migration in vitro. When anti-human IL-8 immunoglobulin G was used for neutralizing neutrophil chemotactic factor (NCF) activities in the culture supernatants of these cells stimulated with 5 microg/ml of PNR, the mean percent reduction of NCF activities were 49-59% in A549 cells and 24-34% in AM. Our present data support that PNR directly stimulates AM and pulmonary epithelial cells to produce IL-8. PNR also mediates neutrophil migration, in part, through IL-8 production from AM and pulmonary epithelial cells. These data suggest the contribution of PNR to the pathogenesis of bronchopulmonary infections due to P. aeruginosa.

Secretion of TNF-alpha, IL-8 and nitric oxide by macrophages activated with polyanions, and involvement of interferon-gamma in the regulation of cytokine secretion

When macrophages derived from rat bone marrow were cultured in the presence of polyanions such as acetyl lignin (EP3), sulfonyl lignin (LS) or dextran sulfate (DS), the cells secreted TNF-alpha, IL-8 and nitric oxide (NO). EP3 had a dose-dependent effect on the secretion of TNF-alpha, IL-8 and NO. EP3 significantly affected secretion at concentrations greater than 5 microg/ml. The EP3 effect was at its maximum between concentrations of 50 and 100 microg/ml. LS and DS induced a slight increase in the secretion of cytokines and NO at a concentration of 100 microg/ml. The use of the reverse-transcription polymerase chain reaction (RT-PCR) showed that the increases in cytokine and NO secretion were due to an increase in cytokine mRNAs or NO synthase mRNA. Anti-TNF-alpha antibodies partially inhibited NO secretion by EP3-activated macrophages, although IL-8 secretion was independent of antibody treatment. The secretion of TNF-alpha and NO was also unaffected by the addition of anti-IL-8 antibodies. The addition of interferon-gamma (IFN-gamma) to the culture medium did not alter TNF-alpha and NO secretion by the EP3-activated macrophages, however, IL-8 secretion was increased when a low concentration of IFN-gamma (0.2 U/ml) was added, but was reduced in the presence of a high concentration of IFN-gamma (2000 U/ml). IFN-gamma produced similar effects on cytokine and NO secretion in macrophages activated with lipopolysaccharide (LPS). Therefore, it is concluded that macrophages treated with polyanions secrete cytokines and NO, and that INF-gamma is involved in the regulatory mechanism of cytokine and NO secretion.

Interleukin-8 stimulates the adhesion of endometrial stromal cells to fibronectin

OBJECTIVE

To study the effect of interleukin-8 (IL-8) and mouse anti-human IL-8 monoclonal antibody on endometrial stromal cell adhesion to fibronectin.

DESIGN

Prospective, controlled in vitro study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing benign gynecologic surgery for indications other than endometrial disease.

INTERVENTION(S)

Endometrial stromal cells were treated with IL-8 and mouse anti-human IL-8 monoclonal antibody at different concentrations and adhesion assays were performed by labeling the cells with calcein.

MAIN OUTCOME MEASURE(S)

Fluorescence in calcein-labeled endometrial stromal cells.

RESULT(S)

IL-8 induced a concentration-dependent increase of cell adhesion to fibronectin matrix (twofold at 10 ng/mL; P = .006). Treatment of endometrial stromal cells with anti-IL-8 neutralizing antibody inhibited partially the cell adhesion.

CONCLUSION(S)

IL-8 stimulates the adhesion of endometrial stromal cells to fibronectin in a concentration-dependent manner. IL-8 may thus be relevant for the attachment of endometrial implants in the pathogenesis of endometriosis.

Stretch induces cytokine release by alveolar epithelial cells in vitro

Mechanical ventilation can injure the lung, causing edema and alveolar inflammation. Interleukin-8 (IL-8) plays an important role in this inflammatory response. We postulated that cyclic cell stretch upregulates the production and release of IL-8 by human alveolar epithelium in the absence of structural cell damage or paracrine stimulation. To test this hypothesis, alveolar epithelial cells (A549 cells) were cultured on a deformable silicoelastic membrane. When stretched by 30% for up to 48 h, the cells released 49 +/- 34% more IL-8 (P < 0.001) than static controls. Smaller deformations (20% stretch) produced no consistent increase in IL-8. Stretch of 4 h duration increased IL-8 gene transcription fourfold above baseline. Stretch had no effect on cell proliferation, cell viability as assessed by (51)Cr release assay, or the release of granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha. We conclude that deformation per se can trigger inflammatory signaling and that alveolar epithelial cells may be active participants in the alveolitis associated with ventilator-induced lung injury.

Specific detection by flow cytometry of histidine-tagged ligands bound to their receptors using a tag-specific monoclonal antibody

Engineering proteins to contain a histidine (His)-tag has proved to be very useful for the purification and analyses of these molecules. In the present study, we demonstrate that the binding of His-tagged ligands to their receptors may be visualised by flow cytometry making use of a selected monoclonal antibody (mAb) against the His-tag. Employing this method, a recombinant C3a (rC3a) anaphylatoxin with a His-tag at its N-terminus could be shown to bind to C3a receptor (C3aR)-expressing RBL-2H3 transfectants with a half-maximal effective concentration (EC50) of about 3 nM which is well within the range of published affinity constants. Binding of a recombinant interleukin-8 (rIL-8) molecule with a C-terminal His-tag to RBL-2H3 cells which stably express the IL-8 receptors CXCR1 or CXCR2 could also be demonstrated using the tag-specific mAb. Furthermore, aminoterminally tagged C5a molecules of rat or human origin could be shown to bind to the human C5a receptor (C5aR). However, the fluorescence signal of the binding of rat rC5a to the human C5aR was distinctly higher over a wide range of ligand concentrations than the signal of human rC5a binding although both ligands were equally potent in the induction of chemotaxis in C5aR-expressing cells. Thus, the tag-specific mAb was able to interfere with the binding of human but not rat rC5a to the human C5aR. This observation is in agreement with the hypothesis of a two binding site model for the interaction of human C5a with its receptor whereas a different binding mode may apply for rat C5a. Our data demonstrate that the selected His-tag specific mAb may be a valuable tool for the visualisation of the binding of recombinant ligands to their receptors and may also provide useful information on the specific binding properties of the ligands.

Migration inhibitory factor related protein-8 (MRP-8) is an autocrine chemotactic factor for periodontal ligament cells

Previous studies have suggested that human periodontal ligament (PDL) cells secrete a chemotactic factor which stimulates motility in an autocrine manner. Here we report the partial amino acid sequence of a purified factor which shows 100% homology with human migration inhibitory factor related protein-8 (MRP-8). In addition, reverse-transcription polymerase chain-reaction (RT-PCR) analysis revealed that mRNA encoding MRP-8 was expressed in cultured human PDL cells. To confirm that MRP-8 is chemotactic for PDL cells, we synthesized 25 mer peptides overlapped by 5 amino acids covering the entire MRP-8 protein and tested them for their chemotactic activities. The data indicated that amino acid residues 21-45 showed chemotactic activity for cultured human PDL cells. The maximum chemotactic response was observed at the concentration of 10(-15) mol/mL for human PDL cells. The chemotactic activity was estimated to be approximately 1000-fold higher than that of platelet-derived growth factor (PDGF), insulin-like growth factors-I and -II (IGF-I, -II), and epidermal growth factor (EGF) when compared on a molar basis. Since MRP-8 is reported to be produced mainly by neutrophils and monocytes, the result of the current study may suggest another important role of MRP-8 in human PDL cells.

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.

Mast Cell Migratory Response to Interleukin-8 Is Mediated Through Interaction With Chemokine Receptor CXCR2/Interleukin-8RB

To explore the role of chemokines in mast cell chemotaxis and accumulation at sites of inflammation, we first investigated the response of human mast cells to 18 different chemokines by induction of intracellular calcium mobilization in the human mast cell line, HMC-1. Only a subgroup of CXC chemokines defined by the conserved sequence motif glutamic acid-leucine-arginine (ELR) tripeptide motif, which included interleukin-8 (IL-8), growth-regulated oncogene  (GRO), neutrophil-activating peptide-2 (NAP-2), and epithelial cell–derived neutrophil activating peptide-78 (ENA-78), induced calcium flux in the cells. These observations suggested that the receptor CXCR2 (IL-8RB) should be expressed on the surface of these cells. Using the RNAse protection assay, CXCR2 mRNA, but not CXCR1 (IL-8RA) mRNA expression was detected in HMC-1 cells. Flow cytometry analysis documented the surface expression of CXCR2. A binding analysis performed with125I-IL-8 determined that there were approximately 3,600 high affinity IL-8 binding sites per HMC-1 cell, with a calculated kd of 1.2 to 2 nmol/L. The activity of this receptor was further explored using IL-8, which was found to induce dose-dependent chemotactic and haptotactic responses in both HMC-1 cells and in vitro cultured human cord blood–derived mast cells. These results show the expression of functional CXCR2 receptors on the surface of human mast cells, which may play an important role in mast cell recruitment during the genesis of an inflammatory response.

Mast Cell Migratory Response to Interleukin-8 Is Mediated Through Interaction With Chemokine Receptor CXCR2/Interleukin-8RB

To explore the role of chemokines in mast cell chemotaxis and accumulation at sites of inflammation, we first investigated the response of human mast cells to 18 different chemokines by induction of intracellular calcium mobilization in the human mast cell line, HMC-1. Only a subgroup of CXC chemokines defined by the conserved sequence motif glutamic acid-leucine-arginine (ELR) tripeptide motif, which included interleukin-8 (IL-8), growth-regulated oncogene  (GRO), neutrophil-activating peptide-2 (NAP-2), and epithelial cell–derived neutrophil activating peptide-78 (ENA-78), induced calcium flux in the cells. These observations suggested that the receptor CXCR2 (IL-8RB) should be expressed on the surface of these cells. Using the RNAse protection assay, CXCR2 mRNA, but not CXCR1 (IL-8RA) mRNA expression was detected in HMC-1 cells. Flow cytometry analysis documented the surface expression of CXCR2. A binding analysis performed with125I-IL-8 determined that there were approximately 3,600 high affinity IL-8 binding sites per HMC-1 cell, with a calculated kd of 1.2 to 2 nmol/L. The activity of this receptor was further explored using IL-8, which was found to induce dose-dependent chemotactic and haptotactic responses in both HMC-1 cells and in vitro cultured human cord blood–derived mast cells. These results show the expression of functional CXCR2 receptors on the surface of human mast cells, which may play an important role in mast cell recruitment during the genesis of an inflammatory response.

Regulation of interleukin-8 gene expression

Interleukin-8 (IL-8), a member of the CXC chemokine family, is an important activator and chemoattractant for neutrophils and has been implicated in a variety of inflammatory diseases. IL-8 is secreted in a stimulus-specific manner by a wide variety of cell types and is regulated primarily at the level of gene transcription. Functional studies indicate that IL-8 transcriptional responses to proinflammatory mediators are rapid and require only 100 nucleotides of 5'-flanking DNA upstream of the TATA box. Within the IL-8 promoter sequence are DNA binding sites for the inducible transcription factors AP-1, NF-IL-6, and NF-kappaB. Transcription factors in these families bind the IL-8 promoter as dimers, and several distinct subunit combinations have been identified as important for IL-8 transcription. In addition, these factors can act in concert to synergistically activate the IL-8 promoter. AP-1 and NF-IL-6 physically interact with NF-kappaB, and functional cooperativity among the factors appears to be critical for optimal IL-8 promoter activity in different cell types. IL-8 transcription appears to be activated by a promoter recruitment mechanism where inducible transcription factor binding to the IL-8 promoter is required for binding of constitutively active TATA box-binding proteins and formation of a stable preinitiation complex. This review discusses the regulatory role these higher-order synergistic interactions play in IL-8 transcription and in generation of the stimulus-specific and cell type-specific patterns of IL-8 expression.

The participation of IL-8 in the synovial lesions at an early stage of rheumatoid arthritis

Synovial tissues from Rheumatoid Arthritis (RA) were divided into three groups based on their histopathological findings and compared for their expression of IL-8 and monocyte chemotactic and activating factor (MCAF) by using immunohistochemistry and in situ hybridization. The levels of IL-8 as well as those of MCAF were markedly higher in the synovial fluid from RA joints. Synovial lining cells (SLC) and macrophages had an ability to produce IL-8 at an early phase of the disease. The presence of MCAF was restricted in macrophages at this stage. On the other hand, the production of IL-8 as well as MCAF were prominent in most components of the joints such as SLC, migrated monocytes, sublining fibroblastoid cells, endothelial cells or migrated neutrophils at an active phase. The expression of IL-8 or MCAF was low in fibrotic synovitis of RA. These data indicate that IL-8 generated from SLC and macrophages may participate to the inflammatory process in the early synovitis of RA.

In vivo selection and characterization of metastatic variants from human pancreatic adenocarcinoma by using orthotopic implantation in nude mice

We determined whether the implantation of human pancreatic cancer cells into the pancreas of nude mice can be used to select variants with increasing metastatic potential. COLO 357 line fast-growing cells were injected into the spleen or pancreas of nude mice. Hepatic metastases were harvested, and tumor cells were reinjected into the spleen or pancreas. This cycle was repeated several times to yield cell lines L3.6sl (spleen to liver) and L3.6pl (pancreas to liver). The variant cells produced significantly higher incidence and number of lymph node and liver metastases than the parental cells. Their increased metastatic potential was associated with increased expression (mRNA and protein) of the proangiogenic molecules basic fibroblast growth factor, vascular endothelial growth factor, and interleukin-8. The metastatic cells also exhibited increased motility and invasiveness, which were associated with increased expression of collagenase type IV (MMP-9) and decreased expression of E-cadherin. Collectively, the data show that the orthotopic implantation of human pancreatic cancer cells in nude mice is a relevant model with which to study the biology of pancreatic cancer metastasis and to select variant cell lines with enhanced metastatic potential.

Interleukin 6 in bile as an indicator of liver function after hepatectomy in patients with biliary tract carcinoma

BACKGROUND

Interleukin (IL) 6 is one of the important components of the early signalling pathways leading to liver regeneration, and has been detected in the bile after liver transplantation. IL-6 concentrations in the bile were studied in an attempt to predict liver function after major hepatectomy for biliary tract carcinoma.

METHODS

This study involved 24 patients without cirrhosis who underwent major hepatectomy for biliary tract carcinoma. The bile was sampled regularly through external biliary drainage tubes. IL-6 concentrations in bile and serum were measured using an enzyme-linked immunosorbent assay.

RESULTS

Bile IL-6 concentrations increased 37-fold (from mean(s.e.) 56(13) pg/ml before hepatectomy to 2071(398) pg/ml on day 1 after operation) in patients without liver failure after hepatectomy (n = 18) and increased sevenfold (from 71(24) to 530(76) pg/ml) in patients with liver failure after hepatectomy (n = 6). The values were significantly lower in patients with liver failure than in those without liver failure (P < 0.05). The bile IL-6 concentration on day 1 after operation exhibited a significant negative correlation with the maximum serum total bilirubin concentration after hepatectomy. Although serum IL-6 concentrations were also increased in both groups after hepatectomy, there was no significant correlation with postoperative liver function.

CONCLUSION

Increased bile IL-6 concentrations after hepatectomy may reflect liver regenerative capacity. Measurement of bile IL-6 concentrations may be clinically useful for the early identification of liver failure after hepatectomy.

Interleukin-8 inhalation directly provokes bronchoconstriction in guinea pigs

BACKGROUND

Although it has been reported that the concentration of interleukin (IL)-8 in nasal lavage fluid and sputum and its production in bronchial epithelium were increased in asthmatic subjects, the direct effects of IL-8 on the airways in vivo is unclear.

METHODS

We examined bronchoconstriction in response to IL-8 inhalation through an endotracheal cannula in anesthetized, artificially ventilated guinea pigs.

RESULTS

Inhalation of IL-8 at concentrations of 1 and 10 microg/ml caused significant bronchoconstriction, as revealed by the elevation of pressure at the airway opening. Moreover, the bronchoconstriction induced by IL-8 was significantly inhibited by the antihistamines diphenhydramine and terfenadine, suggesting the involvement of histamine release in the IL-8-induced bronchoconstriction. No significant leukocyte infiltration was observed in the bronchoalveolar lavage fluid or histologic findings 25 min after the first IL-8 inhalation.

CONCLUSIONS

IL-8 provokes bronchoconstriction without leukocyte accumulation in the airways, mediated in part by histamine release, in guinea pigs.

The serum interleukin 8 level reflects hepatic mitochondrial redox state in hyperthermochemohypoxic isolated liver perfusion with use of a venovenous bypass

BACKGROUND

We have recently developed a simple method of hyperthermochemohypoxic isolated liver perfusion (HILP) as a regional therapy for unrecognized liver micrometastases. However, little is known about the influence of HILP on cytokine production and liver function. We investigated the influence of HILP on interleukin 8 (IL-8) production and the hepatic mitochondrial function and assessed the relationship between these 2 parameters. We also measured the serum tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) levels to examine the involvement of HILP-induced cytokines in the tumor response.

METHODS

Sixteen patients with metastatic liver tumors were randomly assigned to undergo hepatectomy with HILP (group A, n = 9) or hepatectomy alone (group B, n = 7). The isolated liver was perfused for 30 minutes with Ringer's lactate solution containing chemotherapeutic agents warmed to 42 degrees C to 43 degrees C without oxygenation.

RESULTS

The serum IL-8 levels in group A were markedly increased, with peaks at 3 hours after reperfusion, which was significantly higher than levels in group B (P < .01). In group A the arterial ketone body ratio, which reflects the hepatic mitochondrial redox state, decreased during perfusion and was gradually restored to the preperfusion level 1 hour after reperfusion. However, in group B it decreased during hepatectomy but rapidly recovered 5 minutes after hepatectomy. There was a significant negative correlation between the peak serum IL-8 level and the initial velocity of arterial ketone body ratio recovery for the first 5 minutes after reperfusion r = -0.83, P < .001). The serum TNF-alpha and IL-1 beta were temporarily detected only in 3 of 9 patients in group A.

CONCLUSIONS

We have shown that HILP resulted in augmented IL-8 release but not TNF-alpha and IL-1 beta and that the serum IL-8 level reflects the hepatic mitochondrial redox state. These findings suggest that IL-8 production may be associated with hepatic mitochondrial impairment during ischemia. This work may contribute to new therapeutic strategies not only for hepatic ischemia reperfusion injury but also for metastatic liver tumors.

The molecular pathogenesis of endotoxic shock and organ failure

Sepsis is still associated with a high mortality rate. Septic shock and sequential multiple organ failure have a strong correlation with poor outcome. Lipopolysaccharide (LPS) plays a pivotal role in the initiation of host responses to Gram-negative infection. A number of mediators, such as cytokines, nitric oxide and eicosanoids, are responsible for most of the manifestations caused by LPS, and circulatory failure, leukocyte-induced tissue injury and coagulation disorder appear to be critical determinants in the development of sequential organ failure. Although several anti-LPS or anti-cytokine clinical trials have been attempted, none of them has so far been successful.

Sinus mucosal IL-8 gene expression in chronic rhinosinusitis

BACKGROUND

Epithelial hyperplasia and mucosal infiltration of leukocytes are common features of chronic rhinosinusitis. The epithelium can produce chemoattractant cytokines that may contribute to leukocyte infiltration in rhinosinusitis.

OBJECTIVE

We sought to determine whether mucosal IL-8 gene expression is increased in chronic rhinosinusitis and to relate IL-8 gene expression to disease severity.

METHODS

We used both a noncompetitive and a quantitative, competitive reverse transcription-polymerase chain reaction to examine IL-8 gene expression in samples of sinus mucosal tissue obtained during surgery from 22 patients with chronic rhinosinusitis and 9 normal control subjects. IL-8 gene expression was related to disease severity assessed by sinus computed tomography (CT) scores and to symptom scores assessed by means of a questionnaire.

RESULTS

Sinus mucosal IL-8 gene expression was not detected in any of the control subjects but was present in 12 of 22 (55%) patients with rhinosinusitis. Sinus CT scores and symptom scores were both significantly higher in patients with positive mucosal IL-8 gene expression than in subjects with no detectable IL-8 gene expression. Positive IL-8 gene expression was not predicted by history of prior surgery nor by atopic or asthmatic status. In 9 subjects with positive IL-8 gene expression, levels of mRNA expression, assessed by competitive reverse transcription-polymerase chain reaction, correlated significantly (rho = 0.72, P <.05) with sinus CT scores.

CONCLUSION

Sinus mucosal expression of the gene for IL-8 is increased in patients with chronic rhinosinusitis, and the level of IL-8 gene expression correlates with disease severity.

Integrin signalling defects in T-lymphocytes in systemic lupus erythematosus

OBJECTIVE

To establish the relationship between T cell responses to integrin coreceptor stimulation and B cell hyperreactivity as measured by pathologic autoantibody production.

METHODS

Peripheral blood mononuclear cells from 42 patients with SLE according to the American Rheumatism Association criteria were examined for their ability to adhere to plate-immobilised fibronectin. Co-stimulation assays were performed on the same cells using anti-CD3 antibody alone or co-immobilised with an anti-beta1-integrin antibody. Proliferative responses were measured by 3[H]thymidine pulsing on day 3 and activation was determined using a commercial protein kinase C assay, the protocol being established by our group in association with Promega. Beta-integrin expression was established by FACS analysis.

RESULTS

An impaired PKC response to integrin-mediated activation was found in T-lymphocytes from 6/21 (29%) SLE patients, which correlated significantly with an absence of anti-dsDNA antibody in patient sera, irrespective of prednisolone treatment. Integrin co-stimulation of TcR/CD3-induced proliferation and T cell adhesion to fibronectin were also impaired among 5/21 (24%) and 6/15 (40%) patients studied, respectively.

CONCLUSION

We hypothesise that the integrity of beta1-integrin signalling pathways may influence pathological antibody production in SLE by affecting T-lymphocyte activation and interactions between T- and B-lymphocytes.

Detection of serum TNF-α, IFN-γ, IL-6 and IL-8 in patients with hepatitis B

AIM To assess the possible roles of cytokines (TNF-α, IFN-γ, IL-6 and IL-8) in liver damage of hepatitis B.

METHODS The serum TNF-α, IFN-γ, IL-6 and IL-8 were detected by ELISA in 66 patients with hepatitis B and 20 healthy blood donors.

RESULTS TNF-α and IL-6 in all types of clinical hepatitis B were significantly higher than those in healthy blood donors (P < 0.05 ); meanwhile the levels of TNF-α, IFN-γ, IL-6 and IL-8 in the patients with fulminant hepatitis B were much higher than those in the patients with acute hepatitis B(P < 0.05); the level of TNF-α was positively correlated with the levels of IFN-γ, Il-6 and IL-8 in all types of hepatitis B (r_IFN = 0.24, r_IL-6 = 0.35, r_IL-8 = 0.44) and the TNF-α, IFN-γ, IL-6 and IL-8 were positively correlated with serum bilirubin (P < 0.05). Dynamic changes of these cytokines were observed in the course of acute and fulminant hepatitis. The level of IFN-γ peaked in the initial period of acute hepatitis and early stage of hepatic coma in fulminant hepatitis; TNFα, IL-6 and IL-8 increased with exacer-bation, and reached a peak when the liver da-mage was most serious, then decreased when patient conditions were improved.

CONCLUSION The increased cytokines were re-lated to the inflamm ation of liver cells and multi-ple factors may play certain roles in liver dam-age.

Involvement of mitogen-activated protein kinase pathways in interleukin-8 production by human monocytes and polymorphonuclear cells stimulated with lipopolysaccharide or Mycoplasma fermentans membrane lipoproteins

Interleukin-8 (IL-8) is a chemokine that belongs to the alpha-chemokine or CXC subfamily and is produced by a wide variety of human cells, including monocytes and polymorphonuclear cells (PMN). IL-8 is secreted in response to inflammatory stimuli, notably bacterial products such as lipopolysaccharide (LPS), but little is known about the mechanisms by which these agents mediate IL-8 induction. In this report, we show that Mycoplasma fermentans lipid-associated membrane proteins (LAMPf) induce the production of high levels of IL-8 by THP-1 (human monocyte) cells and PMN at the same extent as LPS. It was previously demonstrated that stimulation of monocytic cells with either LPS or LAMPf led to a series of common downstream signaling events, including the activation of protein tyrosine kinase and of mitogen-activated protein kinase cascades. By using PD-98059 and SB203580, two potent and selective inhibitors of MEK1 (a kinase upstream of ERK1/2) and p38, respectively, we have demonstrated that both ERK1/2 and p38 cascades play a key role in the production of IL-8 by monocytes and PMN stimulated with bacterial fractions.

Induction of cytokines in a human colon epithelial cell line by Shiga toxin 1 (Stx1) and Stx2 but not by non-toxic mutant Stx1 which lacks N-glycosidase activity

Stx1 and Stx2 produced by Shiga toxin-producing Escherichia coli are cytotoxic due to their N-glycosidase activity on 28S rRNA. In this study, we have shown that proinflammatory cytokine mRNAs, especially IL-8, were induced by Stx1 and Stx2 in Caco-2 cells. A non-toxic mutant of Stxl which lacks N-glycosidase activity did not induce cytokine mRNAs. IL-8 production at the protein level was enhanced by Stx1 and Stx2, but not by the mutant Stx1. These results demonstrate that Shiga toxins induce expression and synthesis of cytokines in Caco-2 cells and their N-glycosidase activity is essential for the induction.

CC-Chemokine Receptor 6 Is Expressed on Diverse Memory Subsets of T Cells and Determines Responsiveness to Macrophage Inflammatory Protein 3α

CC-chemokine receptor (CCR) 6 is the only known receptor for macrophage inflammatory protein (MIP)-3α, a CC chemokine chemotactic for lymphocytes and dendritic cells. Using anti-serum that we raised against the N-terminal residues of CCR6, we have characterized the surface expression of CCR6 on peripheral blood leukocytes and we have correlated CCR6 expression with responses to MIP-3α. We found that CCR6 was expressed only on memory T cells, including most α4β7 memory cells and cutaneous lymphocyte-associated Ag-expressing cells, and on B cells. Accordingly, chemotaxis of T cells to MIP-3α was limited to memory cells. Moreover, calcium signals on T cells in response to MIP-3α were confined to CCR6-expressing cells, consistent with CCR6 being the only MIP-3α receptor on peripheral blood T cells. Unlike many CC chemokines, MIP-3α produced a calcium signal on freshly isolated T cells, and CCR6 expression was not increased by up to 5 days of treatment with IL-2 or by cross-linking CD3. Despite their surface expression of CCR6, freshly isolated B cells did not respond to MIP-3α. In addition to staining peripheral blood leukocytes, our anti-serum detected CCR6 on CD34+ bone marrow cell-derived dendritic cells. Our data are the first to analyze surface expression of CCR6, demonstrating receptor expression on differentiated, resting memory T cells, indicating differences in receptor signaling on T cells and B cells and suggesting that CCR6 and MIP-3α may play a role in the physiology of resting memory T cells and in the interactions of memory T cells, B cells, and dendritic cells.