Properties of pro-inflammatory cell type-specific leukocyte chemotactic cytokines, interleukin 8 (IL-8) and monocyte chemotactic and activating factor (MCAF)

PoCXCL8, a teleost chemokine, exerts direct bactericidal, chemotactic/phagocytic, and NETs releasing properties, promoting host anti-bacterial immunity

As an important CXC chemokine, CXCL8 plays pleiotropic roles in immunological response. In teleost, CXCL8 is involved in cell migration and bacterial invasion. However, the immune antibacterial function of CXCL8 in Japanese flounder (Paralichthys olivaceus) (PoCXCL8) is largely scarce. In this research, we investigated the antibacterial property and leukocyte activation of PoCXCL8. PoCXCL8 consists of 100 amino acid residues, with a conserved chemokine CXC domain. PoCXCL8 was expressed in various tissues, with the highest level in liver and the lowest level in muscle, and sharply induced by V. harveyi or E. tarda in liver, spleen, and head kidney. In vitro, the recombinant PoCXCL8 (rPoCXCL8) could bind to Bacillus subtilis, Edwardsiella tarda, Escherichia coli, Pseudomonas fluorescens, Vibrio anguillarum, Vibrio harveyi, Staphylococcus aureus, and Micrococcus luteus, affect the growth of E. coli, E. tarda, M. luteus, and P. fluorescens, and have a direct bactericidal effect on E. coli and E. tarda. Moreover, rPoCXCL8 was able to bind the outer membranal protein rPilA of E. tarda. In addition, rPoCXCL8 could bind to PBLs, activating the PBLs activity including chemotaxis, proliferation, phagocytosis, reactive oxygen species, acid phosphatase activity. At same time, rPoCXCL8 could induce neutrophil to generate neutrophil extracellular traps (NETs) and promote the expression of inflammatory genes including IL-1β, IL6, MMP13, TNF-α, and NF-κB. In flounder, the presence of rPoCXCL8 could enhance the in vivo resistance to E. tarda in liver, spleen, and head kidney. Moreover, the PoCXCL8-deficient could attenuate the fish defense against E. tarda infection in in spleen and head kidney. In conclusion, these results provided new insights into the antibacterial properties of CXCL8 in P. olivaceus.

Abnormal Fetal Lung of Hoxa1-/- Piglets Is Rescued by Maternal Feeding with All-Trans Retinoic Acid

Neonatal Hoxa1-/- piglets were characterized by dyspnea owing to the Hoxa1 mutation, and maternal administration with ATRA alleviated the dyspnea of neonatal Hoxa1-/- piglets. The purpose of this experiment was to explore how maternal ATRA administration rescued the abnormal fetal lungs of Hoxa1-/- piglets. Samples of the lungs were collected from neonatal Hoxa1-/- and non-Hoxa1-/- piglets delivered by sows in the control group, and from neonatal Hoxa1-/- piglets born by sows administered with ATRA at 4 mg/kg body weight on dpc 12, 13, or 14, respectively. These were used for the analysis of ELISA, histological morphology, immunofluorescence staining, immunohistochemistry staining, and quantitative real-time PCR. The results indicate that the Hoxa1 mutation had adverse impacts on the development of the alveoli and pulmonary microvessels of Hoxa1-/- piglets. Maternal administration with ATRA at 4 mg/kg body weight on dpc 14 rescued the abnormal lung development of Hoxa1-/- piglets by increasing the IFN-γ concentration (p < 0.05), airspace area (p < 0.01) and pulmonary microvessel density (p < 0.01); increasing the expression of VEGFD (p < 0.01), PDGFD (p < 0.01), KDR (p < 0.01), ID1 (p < 0.01), and NEDD4 (p < 0.01); and decreasing the septal wall thickness (p < 0.01) and the expression of SFTPC (p < 0.01) and FOXO3 (p < 0.01). Maternal administration with ATRA plays a vital role in rescuing the abnormal development of lung of Hoxa1-/- fetal piglets.

Cytokines in Febrile Diseases

The human body has a perfect thermoregulatory system to meet the needs of normal life activities. The central regulation of body temperature is mainly explained by the theory of "setting point (setpoint, SP)". Fever is a positive but nonspecific response of the body to infections and other pyrogens, which causes immune cells to release cytokines, leading to a brain protein-mediated rise in body temperature. Cytokines can be roughly divided into 2 categories: proinflammatory cytokines and anti-inflammatory cytokines. IL-1, TNF-α, and IL-6 are proinflammatory cytokines, whereas IL-4 and IL-10 are anti-inflammatory cytokines. IL-2 is a cytokine that can both activate and inhibit immunity. IL-8 is a neutrophil chemotactic factor, and IFN is a cytokine that plays a key role in the proper induction and maintenance of innate and acquired immunity. This article reviews the pathophysiological characteristics of fever and the cytokines related to fever (IL-2, 4, 6, 8, 10, IFN, TNF, etc.).

Biliary Tract Carcinogenesis Model Based on Bile Metaproteomics

Purpose: To analyze human and bacteria proteomic profiles in bile, exposed to a tumor vs. non-tumor microenvironment, in order to identify differences between these conditions, which may contribute to a better understanding of pancreatic carcinogenesis.

Patients and Methods: Using liquid chromatography and mass spectrometry, human and bacterial proteomic profiles of a total of 20 bile samples (7 from gallstone (GS) patients, and 13 from pancreatic head ductal adenocarcinoma (PDAC) patients) that were collected during surgery and taken directly from the gallbladder, were compared. g:Profiler and KEGG (Kyoto Encyclopedia of Genes and Genomes) Mapper Reconstruct Pathway were used as the main comparative platform focusing on over-represented biological pathways among human proteins and interaction pathways among bacterial proteins.

Results: Three bacterial infection pathways were over-represented in the human PDAC group of proteins. IL-8 is the only human protein that coincides in the three pathways and this protein is only present in the PDAC group. Quantitative and qualitative differences in bacterial proteins suggest a dysbiotic microenvironment in the PDAC group, supported by significant participation of antibiotic biosynthesis enzymes. Prokaryotes interaction signaling pathways highlight the presence of zeatin in the GS group and surfactin in the PDAC group, the former in the metabolism of terpenoids and polyketides, and the latter in both metabolisms of terpenoids, polyketides and quorum sensing. Based on our findings, we propose a bacterial-induced carcinogenesis model for the biliary tract.

Conclusion: To the best of our knowledge this is the first study with the aim of comparing human and bacterial bile proteins in a tumor vs. non-tumor microenvironment. We proposed a new carcinogenesis model for the biliary tract based on bile metaproteomic findings. Our results suggest that bacteria may be key players in biliary tract carcinogenesis, in a long-lasting dysbiotic and epithelially harmful microenvironment, in which specific bacterial species' biofilm formation is of utmost importance. Our finding should be further explored in future using in vitro and in vivo investigations.

An impedimetric immunosensor for highly sensitive detection of IL-8 in human serum and saliva samples: A new surface modification method by 6-phosphonohexanoic acid for biosensing applications

In this study, we fabricated a sensitive and label-free impedimetric immunosensor based on 6-phosphonohexanoic acid (PHA) modified ITO electrode for detection of interleukin-8 (IL-8) in human serum and saliva. PHA was first employed to cancer biomarker sensing platform. Anti-IL-8 antibody was used as a biorecognition element and the detection principle of this immunosensor was based on monitoring specific interaction between anti-IL-8 antibody and IL-8 antigen. The morphological characterization of each electrode modification step was analyzed by scanning electron microscopy (SEM), SEM-energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) while electrochemical characterization was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and single frequency impedance (SFI) techniques. Moreover, the antibody immobilization on the electrode surface was proved Fourier-transform infrared spectroscopy (FTIR) and Raman Spectroscopy. This proposed impedimetric immunosensor exhibited good performances with a wide linear in the range from 0.02 pg/mL to 3 pg/mL as well as a relative low detection limit of 6 fg/mL. The impedimetric immunosensor had a good specificity, stability and reproducibility. This study proved that PHA was a suitable interface material to fabricate an electrochemical biosensor.

Opposing Regulation of Interleukin-8 and NF-kB Responses by Lipoxin A4 and Serum Amyloid a via the Common Lipoxin a Receptor

Lipoxin A4 (LXA4) is a potent eicosanoid that inhibits IL-1β-induced activation of human fibroblast-like synoviocytes (FLS) via the LXA4 receptor (ALXR). Serum amyloid A (SAA) is an acute phase reactant with cytokine-like properties. SAA has been shown to bind the same seven transmembrane G protein-coupled receptor ligated by LXA4. Here we compared the inflammatory responses of lipid (LXA4) and peptide (SAA) ligands in human FLS via the shared ALX and characterized their downstream signaling. LXA4 induced stimulation of tissue inhibitors of metalloproteinase-2, whereas SAA induced interleukin-8 and matrix metalloproteinase-3 production. SAA up-regulated NF-kB and AP-1 DNA binding activity, while LXA4 markedly inhibited these responses after IL-1β stimulation. A human IL-8 promoter luciferase construct was transfected into CHO cells stably expressing ALXR in order to determine the role of NF-kB and/or AP-1 in the regulation of IL-8 gene expression. The NF-kB pathway proved to be the preeminent for the biological responses elicited by both ligands. These findings suggest that two endogenous molecules, targeting a common receptor, could participate in the pathogenesis of inflammatory arthritis by differentially regulating inflammatory responses in tissues expressing the ALXR.

Cytokine profile after oral food challenge in infants with food protein-induced enterocolitis syndrome

BACKGROUND

Although food protein-induced enterocolitis syndrome (FPIES) is supposed to be caused by inflammation, the role of cytokines has not yet been clarified.

METHODS

To elucidate the role of cytokines in the development of symptoms and abnormal laboratory findings at an oral food challenge (OFC), changes in serum cytokine levels were analyzed for 6 OFCs in 4 patients with FPIES. The result of OFC was judged positive if any gastrointestinal (GI) symptoms (vomiting, diarrhea, or bloody stool) were induced.

RESULTS

Among 11 cytokines profiled, serum levels of interleukin (IL)-2, IL-5, and IL-8 were clearly increased in all 4 positive OFCs in which elevations of the serum level of C-reactive protein (CRP) and peripheral blood neutrophilia were also seen. The level of serum IL-10 also rose in 2 positive OFCs. Remarkable increases in the serum level of interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), IL-6, and IL-12 were observed in a positive OFC where the serum level of CRP rose markedly (6.75 mg/dL). The serum levels of IL-5 were also elevated in 2 negative OFCs. No apparent specific correlations were found between cytokines and GI symptoms.

CONCLUSIONS

These results suggest that IL-2 and IL-8 are involved in the antigen-specific immune responses in most patients with FPIES. Further studies are needed to elucidate the significance of these cytokine in the pathogenesis of FPIES.

Early gestation chorionic villi-derived stromal cells for fetal tissue engineering

AIM: To investigate the potential for early gestation placenta-derived mesenchymal stromal cells (PMSCs) for fetal tissue engineering.

METHODS: PMSCs were isolated from early gestation chorionic villus tissue by explant culture. Chorionic villus sampling (CVS)-size tissue samples (mean = 35.93 mg) were used to test the feasibility of obtaining large cell numbers from CVS within a clinically relevant timeframe. We characterized PMSCs isolated from 6 donor placentas by flow cytometry immunophenotyping, multipotency assays, and through immunofluorescent staining. Protein secretion from PMSCs was examined using two cytokine array assays capable of probing for over 70 factors in total. Delivery vehicle compatibility of PMSCs was determined using three common scaffold systems: fibrin glue, collagen hydrogel, and biodegradable nanofibrous scaffolds made from a combination of polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). Viral transduction of PMSCs was performed using a Luciferase-GFP-containing lentiviral vector and efficiency of transduction was tested by fluorescent microscopy and flow cytometry analysis.

RESULTS: We determined that an average of 2.09 × 10⁶ (SD ± 8.59 × 10⁵) PMSCs could be obtained from CVS-size tissue samples within 30 d (mean = 27 d, SD ± 2.28), indicating that therapeutic numbers of cells can be rapidly expanded from very limited masses of tissue. Immunophenotyping by flow cytometry demonstrated that PMSCs were positive for MSC markers CD105, CD90, CD73, CD44, and CD29, and were negative for hematopoietic and endothelial markers CD45, CD34, and CD31. PMSCs displayed trilineage differentiation capability, and were found to express developmental transcription factors Sox10 and Sox17 as well as neural-related structural proteins NFM, Nestin, and S100β. Cytokine arrays revealed a robust and extensive profile of PMSC-secreted cytokines and growth factors, and detected 34 factors with spot density values exceeding 10³. Detected factors had widely diverse functions that include modulation of angiogenesis and immune response, cell chemotaxis, cell proliferation, blood vessel maturation and homeostasis, modulation of insulin-like growth factor activity, neuroprotection, extracellular matrix degradation and even blood coagulation. Importantly, PMSCs were also determined to be compatible with both biological and synthetic material-based delivery vehicles such as collagen and fibrin hydrogels, and biodegradable nanofiber scaffolds made from a combination of PLA and PLGA. Finally, we demonstrated that PMSCs can be efficiently transduced (> 95%) with a Luciferase-GFP-containing lentiviral vector for future in vivo cell tracking after transplantation.

CONCLUSION: Our findings indicate that PMSCs represent a unique source of cells that can be effectively utilized for in utero cell therapy and tissue engineering.

Molecular characterization, expression analysis, and biological effects of interleukin-8 in grass carp Ctenopharyngodon idellus

Interleukin-8 (IL-8) is a CXC chemokine that plays key regulatory roles in the immune and inflammatory responses implicated in many human diseases. In this study, we identified and characterized an IL-8 homologue from the grass carp, Ctenopharyngodon idellus. A sequence alignment of the full-length cDNA and genomic DNA showed that the exon/intron organization of grass carp IL-8 (gcIL-8) is identical to those of other known CXC chemokine genes. A multiple alignment analysis showed that gcIL-8 is an ELR(-)CXC chemokine, and its deduced amino acid sequence shares 81% and 36% identity with common carp IL-8s L1 (GenBank ID: ABE47600) and L2 (GenBank ID: AB470924), respectively, suggesting that it belongs to the lineage 1 group of fish IL-8 proteins. On a phylogenetic tree, gcIL-8 clustered with other teleost IL-8 proteins to form a fish-specific clade, clearly distinct from those of bird, mammal, and amphibian proteins. Real-time quantitative PCR analysis indicated that gcIL-8 is differentially expressed in various tissues under normal conditions and that the expression of gcIL-8 mRNA in immune-related tissues is clearly upregulated by Aeromonas hydrophila infection. To explore the biological effects of gcIL-8, we produced a recombinant protein, rgcIL-8, in a prokaryotic expression system. Purified rgcIL-8 was confirmed to be chemoattractive for head kidney neutrophils and mononuclear leukocytes in vitro. Our histopathological study also revealed that rgcIL-8 exerts proinflammatory effects by inducing neutrophil infiltration and erythrocyte extravasation. Overall, these results suggest that IL-8 is crucially involved in the inflammatory responses of fish.

Enhancing neutralizing antibody production by an interferon-inducing porcine reproductive and respiratory syndrome virus strain

Porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) continues to cause substantial economic losses to the global swine industry. PRRSV appears to inhibit synthesis of type I interferons (IFNs), such as IFN-α and -β, which are critical for the innate immunity and play an important role in the modulation of adaptive immunity. An atypical PRRSV strain, A2MC2, is able to induce type I IFNs in vitro. In this study, A2MC2 induction of neutralizing antibodies in vivo was compared with the Ingelvac PRRS modified live virus (MLV) vaccine strain and VR-2385 (a moderate virulent strain). Three-week-old pigs were exposed to these PRRSV strains via intranasal or intramuscular routes to also account for a possible effect of inoculation routes. The interferon-inducing A2MC2 resulted in earlier onset and significantly higher levels of PRRSV neutralizing antibodies than the MLV. In addition, the A2MC2-induced neutralizing antibodies were capable of neutralizing VR-2385, a heterologous strain. The pigs exposed via intranasal route had higher titers of neutralizing antibodies than those injected via intramuscular route. Macroscopic and microscopic lung lesions 14 days post-exposure indicated that A2MC2 had similar virulence in vivo as VR-2385. Pulmonary alveolar macrophages (PAMs) collected during the necropsy 14 days post-exposure in the A2MC2 group had higher level expression of IFN-γ than the MLV group. These results indicate that A2MC2 can be further explored for development of an improved vaccine against PRRS.

Increased levels of serum and gingival crevicular fluid monocyte chemoattractant protein-1 in smokers with periodontitis

BACKGROUND

Smoking alters the host response, including vascular function, neutrophil/monocyte activities, adhesion molecule expression, antibody production, and cytokine and inflammatory mediator release. Monocyte chemoattractant protein-1 (MCP-1) is involved in the activation and recruitment of inflammatory and immune cells to infected sites, thereby mediating a variety of pathophysiologic conditions. Estimation of serum and gingival crevicular fluid (GCF) MCP levels could be a reliable indicator of periodontal disease activity. Hence, the objective of this study is to analyze the serum and GCF MCP-1 levels of smokers and never-smokers with periodontitis and compare them with those in periodontally healthy individuals.

METHODS

A total of 90 participants (30 periodontally healthy individuals, 30 non-smoking individuals with periodontitis, and 30 smokers with periodontitis) formed the study group. Serum and GCF samples were collected, and MCP-1 levels were estimated using enzyme-linked immunosorbent assay.

RESULTS

Mean MCP-1 levels in serum and GCF were found to be highest in smokers with periodontitis, followed by the periodontitis group, and then by the healthy controls. The values were statistically significant (P <0.001).

CONCLUSIONS

It can be concluded that the high levels of both serum and GCF MCP-1 found in smokers could explain the severity of periodontitis in smokers. More longitudinal, prospective studies will help to verify the observations of the present study. Further research in this direction could reveal reliable markers to forecast the progression of periodontitis in high-risk groups.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

HCl-induced and ATP-dependent upregulation of TRPV1 receptor expression and cytokine production by human esophageal epithelial cells

The pathogenesis of gastroesophageal reflux disease (GERD) remains elusive, but recent evidence suggests that early secretion of inflammatory cytokines and chemokines by the mucosa leads to influx of immune cells followed by tissue damage. We previously showed that exposure of esophageal mucosa to HCl causes ATP release, resulting in activation of acetyl-CoA:1-O-alkyl-sn-glycero-3-phosphocholine acetyltransferase (lyso-PAF AT), the enzyme responsible for the production of platelet-activating factor (PAF). In addition, HCl causes release of IL-8 from the esophageal mucosa. We demonstrate that esophageal epithelial cells secrete proinflammatory mediators in response to HCl and that this response is mediated by ATP. Monolayers of the human esophageal epithelial cell line HET-1A were exposed to acidified cell culture medium (pH 5) for 12 min, a total of seven times over 48 h, to simulate the recurrent acid exposure clinically occurring in GERD. HCl upregulated mRNA and protein expression for the acid-sensing transient receptor potential cation channel, subfamily vanilloid member 1 (TRPV1), lyso-PAF AT, IL-8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α, and monocyte chemoattractant protein-1. The chemokine profile secreted by HET-1A cells in response to repeated HCl exposure parallels similar findings in erosive esophagitis patients. In HET-1A cells, the TRPV1 agonist capsaicin reproduced these findings for mRNA of the inflammatory mediators lyso-PAF AT, IL-8, and eotaxin-1. These effects were blocked by the TRPV1 antagonists iodoresiniferatoxin and JNJ-17203212. These effects were imitated by direct application of ATP and blocked by the nonselective ATP antagonist suramin. We conclude that HCl/TRPV-induced ATP release upregulated secretion of various chemoattractants by esophageal epithelial cells. These chemoattractants are selective for leukocyte subsets involved in acute inflammatory responses and allergic inflammation. The data support the validity of HET-1A cells as a model of the response of the human esophageal mucosa in GERD.

Host-bacteria crosstalk at the dentogingival junction

The dentogingival junction is of crucial importance in periodontal host defense both structurally and functionally. Oral bacteria exert a constant challenge to the host cells and tissues at the dentogingival junction. The host response is set up to eliminate the pathogens by the innate and adaptive defense mechanisms. In health, the commensal bacteria and the host defense mechanisms are in a dynamic steady state. During periodontal disease progression, the dental bacterial plaque, junctional epithelium (JE), inflammatory cells, connective tissue, and bone all go through a series of changes. The tissue homeostasis is turned into tissue destruction and progression of periodontitis. The classical study of Slots showed that in the bacterial plaque, the most remarkable change is the shift from gram-positive aerobic and facultatively anaerobic flora to a predominantly gram-negative and anaerobic flora. This has been later confirmed by several other studies. Furthermore, not only the shift of the bacterial flora to a more pathogenic one, but also bacterial growth as a biofilm on the tooth surface, allows the bacteria to communicate with each other and exert their virulence aimed at favoring their growth. This paper focuses on host-bacteria crosstalk at the dentogingival junction and the models studying it in vitro.

Liver interleukin-8 messenger RNA expression and interferon sensitivity-determining region mutations relate to treatment response in hepatitis C 1b

BACKGROUND

In vitro study has shown that mechanisms for inhibiting interferon (IFN)-α antiviral action by non-structural 5A protein include interaction with IFN-induced RNA-dependent protein kinase and induction of interleukin (IL)-8 expression. Mutations in the non-structural 5A IFN sensitivity-determining region (ISDR) were reported to correlate with sustained virological response (SVR). IL-8 is associated with the inhibition of IFN-α action. We investigated whether pretreatment ISDR mutations and hepatic IL-8 messenger RNA (mRNA) expression had an effect on the SVR rate under combination therapy.

METHODS

A total of 53 HCV-1b patients who completed 24 weeks of pegylated-IFN-α2b plus ribavirin, a 24-week follow-up and had enough tissue specimens were enrolled. Liver biopsy was performed within 6 months before antiviral therapy. Hepatic IL-8 mRNA expression was measured by real-time reverse transcriptase PCR.

RESULTS

Of 53 patients, 30 exhibited SVR. Multivariate analysis revealed that hepatic IL-8 mRNA expression <1.5×10(-4) (OR 6.66, 95% CI 1.77-25.05) and ISDR mutations ≥4 (OR 12.20, 95% CI 1.23-125.00) were independent predictors of SVR. Fibrosis scores and alanine aminotransferase levels were predictive of hepatic IL-8 mRNA expression by multiple linear regression analysis (r(2)=0.204).

CONCLUSIONS

SVR to combination therapy in hepatitis C 1b patients was associated with down-regulated hepatic IL-8 mRNA expression and ISDR mutations. Fibrosis scores and alanine aminotransferase levels were predictive of hepatic IL-8 mRNA expression.

Circulating levels of visfatin, resistin and pro-inflammatory cytokine interleukin-8 in acute pancreatitis

BACKGROUND

Resistin and visfatin, hormones produced by adipose tissue, have pro-inflammatory potential; however, their role in acute pancreatitis (AP) has been investigated only rarely.

METHODS

The study group comprised 32 patients with alcoholic AP and 30 controls. In all cases AP was classified as C according to Balthazar's CT score and as severe according to Ranson's criteria. The serum level of visfatin, resistin, and interleukin(IL)-8 immunoassays were measured by ELISA on admission and on the third and fifth day of hospitalization.

RESULTS

On the admission day serum resistin and IL-8 concentrations in AP patients were significantly higher than in controls and they further increased on the third and fifth day of hospitalization. On the admission day serum visfatin levels in AP patients were significantly higher than in controls and further increased on the third day of hospitalization. On the fifth day the levels decreased; however, they were still higher than on admission. The correlation between visfatin and resistin as well as between C-reactive protein and visfatin, resistin and IL-8 levels has been found.

CONCLUSION

In the course of AP, visfatin and resistin levels increase in parallel with C-reactive protein. We speculate that those parameters may provide an additional tool for the prognosis and monitoring of AP. and IAP.

Expression of biologically active recombinant ferret (Mustela putorius furo) interleukin-8 from Escherichia coli

The authors expressed recombinant ferret interleukin-8 protein (rfrIL-8) in Escherichia coli as a glutathione-S-transferase fusion protein. Western blot analyses revealed that anti-ovine IL-8 antibody reacted with rfrIL-8 at 10 kDa. To confirm that the rfrIL-8 was biologically active, the authors examined chemotaxis and respiratory burst activity of ferret polymorphonuclear blood cells (PMNs) exposed to rfrIL-8. The rfrIL-8 strongly induced chemotactic and respiratory burst activities in a statistically significant manner as compared with a negative control. Thus, the authors were able to successfully express biologically active rfrIL-8.

The role of serum interleukin-8 in hepatic resections

PURPOSE

Interleukin-8 (IL-8) is a neutrophil chemotactic factor, which is associated with some inflammatory diseases and various types of surgical stress. The aim of this study was to investigate whether the early postoperative serum IL-8 level may potentially be a new indicator of a surgical stress in patients undergoing a hepatic resection.

METHODS

The serum IL-8 levels were measured in 37 patients who underwent a hepatectomy. The serum IL-8 levels were serially measured using an enzyme-linked immunosorbent assay both before and after a hepatic resection. In addition, the correlation between the postoperative IL-8 value and several clinical variables were examined.

RESULTS

The mean level of IL-8 significantly increased immediately after the operation (P < 0.01 vs before the operation) and decreased on the first postoperative day (POD 1, P < 0.05 vs after the operation). The early postoperative IL-8 levels positively correlated with the length of the procedure (r = 0.383; P < 0.05), the estimated blood loss (r = 0.483; P < 0.01) and the serum bilirubin level on POD 1 (r = 0.390; P < 0.05), and inversely correlated with the white blood cell counts (r = -0.388; P < 0.05) and lymphocyte counts on POD 1 (r = -0.424; P < 0.05). In a comparison of the postoperative IL-8 levels with the surgical factors, there was a significant difference in the extension of the resection (P < 0.05) and in blood transfusion. The patients with a fever of more than 38 degrees C showed higher levels of IL-8 immediately after the operation than those without fever (P < 0.01).

CONCLUSIONS

The early postoperative serum IL-8 level was found to correlate with the degree of the severity of surgery in patients undergoing a hepatic resection, and it is also considered to be a new indicator of surgical stress and liver injury.

Immune and Inflammatory Responses in GERD and Lansoprazole

The exact pathophysiological mechanisms responsible for gastroesophageal reflux disease (GERD) remain unclear. Recent studies have shown that mucosal immune and inflammatory responses, characterized by specific cytokine and chemokine profiles, may underlie the diverse esophageal phenotypes of GERD. Interleukin 8 (IL-8), a representative chemokine, mediates neutrophil trafficking via its receptors, mainly CXCR-1. The IL-8 mRNA and protein levels are increased in the esophageal mucosa, not only in reflux esophagitis (RE), but also in endoscopy-negative GERD (NERD), through activation of nuclear factor-kappaB (NF-kappaB), which is a pivotal transcription factor. Mucosal IL-8 concentrations have been found to parallel the endoscopic severity of RE, implying that this cytokine is a key player in the development of GERD. The mucosal levels of the C-C chemokines, macrophage chemoattractant protein 1 (MCP-1) and regulated on activation normal T-cell-expressed and presumably secreted (RANTES), which primarily attract monocytes and lymphocytes to the site of inflammation, respectively, are also elevated in RE. The secreted levels of IL-8 and IL-1beta, a prototype of proinflammatory cytokine, are maximal at the proximal segment within Barrett esophagus (BE) tissue. The expression of the two pleiotrophic proinflammatory cytokines, IL-6 and tumor necrosis factor alpha, is enhanced in the intestinal epithelium of BE, which places this epithelium at a higher risk for developing malignancy. BE is characterized by a distinct Th-2 predominant cytokine profile (IL-4 and -10), compared to the proinflammatory nature of RE (interferone-gamma). Treatment with a proton pump inhibitor, lansoprazole reduces the mucosal levels of IL-8 mRNA and protein in GERD, including RE and NERD. This may occur in part through an anti-inflammatory action of proton pump inhibitors beyond gastric acid inhibition.

Cytokine--chemokine and apoptotic signatures in patients with hepatitis C

Cytokines and chemokines are proteins that play a critical role in the regulation of immunity and inflammation in patients with chronic Hepatitis C. The aim of our study was to correlate serum cytokines, chemokines and apoptosis in non-treated chronic hepatitis C patients with various degrees of inflammation and fibrosis. We studied 778 patients: 59 had low Knodell fibrosis score and low Knodell histological activity index; 372 had mild fibrosis and low histological activity index; 270 had moderate fibrosis and moderate histological activity index; and, 77 had high fibrosis and high histological activity index on their biopsy. Serum cytokines, chemokines and apoptosis were measured by enzyme-linked-immunosorbent-assay. Multivariate analysis was employed for statistical purposes. A positive correlation was seen between the degree of inflammation and tumor necrosis factor-alpha (TNF-alpha) levels (r = 0.92) in non-cirrhotic patients and between interleukin 2 in all patients (r = 0.85). Interleukin-8 increased significantly at higher histological activity indices and continued to increase in patients with cirrhosis. Transforming growth factor-beta (TGF-beta) levels increased significantly with the severity of fibrosis, but decreased in cirrhotics. In conclusion, cytokines, chemokines and apoptosis levels reflect the progression of inflammation and fibrosis in hepatitis C infected patients, but their signatures differ.

Regulation of CXCL-8 (interleukin-8) induction by double-stranded RNA signaling pathways during hepatitis C virus infection

Hepatitis C virus (HCV) infection induces the alpha-chemokine interleukin-8 (CXCL-8), which is regulated at the levels of transcription and mRNA stability. In the current study, CXCL-8 regulation by double-stranded (ds)RNA pathways was analyzed in the context of HCV infection. A constitutively active mutant of the retinoic acid-inducible gene I (RIG-I), RIG-N, activated CXCL-8 transcription. Promoter mutagenesis experiments indicated that NF-kappaB and interferon (IFN)-stimulated response element (ISRE) binding sites were required for the RIG-N induction of CXCL-8 transcription. IFN-beta promoter stimulator 1 (IPS-1) expression also activated CXCL-8 transcription, and mutations of the ISRE and NF-kappaB binding sites reduced and abrogated CXCL-8 transcription, respectively. In the presence of wild-type RIG-I, transfection of JFH-1 RNA or JFH-1 virus infection of Huh7.5.1 cells activated the CXCL-8 promoter. Expression of IFN regulatory factor 3 (IRF-3) stimulated transcription from both full-length and ISRE-driven CXCL-8 promoters. Chromatin immunoprecipitation assays demonstrated that IRF-3 and NF-kappaB bound directly to the CXCL-8 promoter in response to virus infection and dsRNA transfection. RIG-N stabilized CXCL-8 mRNA via the AU-rich element in the 3' untranslated region of CXCL-8 mRNA, leading to an increase in its half-life following tumor necrosis factor alpha induction. The data indicate that HCV infection triggers dsRNA signaling pathways that induce CXCL-8 via transcriptional activation and mRNA stabilization and define a regulatory link between innate antiviral and inflammatory cellular responses to virus infection.

The 6-fluoro-8-methoxy quinolone gatifloxacin down-regulates interleukin-8 production in prostate cell line PC-3

Fluoroquinolones exhibit immunomodulatory effects on monocytes and macrophages, in addition to their bactericidal activities. It remains unknown even whether the quinolones act directly on the prostate. This study was based on the understanding of the molecular mechanisms of the actions of the fluoroquinolones that can be used for the treatment of chronic prostatitis/chronic pelvic pain syndrome. We investigated whether the 6-fluroro-8-methoxy quinolone gatifloxacin (GFLX) affected the production and secretion of interleukin-8 (IL-8) in the prostate cell line PC-3. GFLX decreased the level of IL-8 release from unstimulated PC-3 cells. GFLX also attenuated IL-8 secretion from PC-3 cells stimulated with peptidoglycan, Mycoplasma hominis, phorbol ester, and tumor necrosis factor alpha (TNF-alpha), indicating that GFLX exhibits an anti-inflammatory effect on the prostate cell line. However, GFLX failed to alter activation of the NF-kappaB and AP-1 elicited by these stimulants. GFLX significantly attenuated the expression of IL-8 mRNA in TNF-alpha-stimulated PC-3 cells and down-regulated the transcriptional activity of the 5'-flanking region of the IL-8 gene from -1481 to +44 bp. The deletion construct without the 5'-flanking region from -1481 to -170 bp but not the construct without the region from -1481 to -188 bp reversed the suppressive effect of GFLX on IL-8 promoter activity. These results demonstrate that GFLX suppresses IL-8 expression in the prostate cell line by decreasing the promoter activity of the IL-8 gene.

Host-bacterial interaction in the development of gastric precancerous lesions in a high risk population for gastric cancer in Venezuela

Helicobacter pylori (HP) infection affects over 50% of the world's population. The prevalence is over 90% in populations at high risk for gastric cancer, but clinical outcomes of the infection are highly variable and thus host genetic factors have been suggested to play a role in its outcomes in addition to bacterial factors. In this study, we examined the effects of common functional genetic polymorphisms of several proinflammatory cytokines known to be overexpressed in HP-infected gastric mucosa on the risk of various stages of gastric premalignant lesions. The odds ratios (ORs) and 95% confidence intervals (CI) for atrophic gastritis, intestinal metaplasia and dysplasia were estimated by multinominal logistic regression analysis among 2,033 Venezuelan subjects. There was a significant effect of IL8 -251A allele on the prevalence of dysplasia (p = 0.021). The OR associated with the A-allele was 1.34 (95% CI: 0.82-2.18) for heterozygotes and 2.00 (95% CI: 1.13-3.56) for homozygotes, compared with the TT genotype. Furthermore, there was a statistically significant interaction between the number of A-alleles and HP cag A genotype (p = 0.009), suggesting that the A-allele increased the risk of dysplasia only when cag A was present. The OR for the AA compared with TT genotype was 3.22 (95% CI: 1.60-6.52) in this group. There were no associations with other proinflammatory cytokines studied, i.e., IL1 beta, IL6, monocyte chemoattractant protein 1 (MCP1) and TNF alpha, or with other stages of premalignant lesions. The present study provides important evidence suggesting host-bacterial interactions in the development of gastric precancerous lesions.

Neutrophil elastase induces IL-8 gene transcription and protein release through p38/NF-{kappa}B activation via EGFR transactivation in a lung epithelial cell line

In this study, we investigated the regulation and mechanism of IL-8 expression by A549 human lung carcinoma cells treated with neutrophil elastase (NE). NE-treated cells exhibited significantly higher IL-8 protein levels in culture media compared with cells treated with vehicle alone. Blocking of gene transcription with actinomycin D suggested that NE stimulated IL-8 synthesis via increased mRNA expression, which was verified by real-time RT-PCR. NE activated the IL-8 promoter but did not alter the stability of its mRNA, confirming that the protease induced IL-8 synthesis through increased gene transcription. The results from the use of chemical inhibitors and mutant gene constructs against various signal transduction components seem to suggest the linear signaling pathway involving the activation of PKC-delta --> dual oxidase 1 --> reactive oxygen species --> TNF-alpha-converting enzyme --> EGF receptor --> p38 --> NF-kappaB for NE-activated IL-8 gene expression. A NF-kappaB potential binding site, located between nucleotides -82 and -69 of the IL-8 promoter, was identified as necessary for NE-induced IL-8 transcription. We conclude that NE increases IL-8 transcription through p38/NF-kappaB activation via EGFR transactivation.

Monocyte chemotactic protein-1 in the follicle of the menstrual and IVF cycle

Ovulation constitutes an inflammatory-like process, with macrophages migrating into the follicle. This study evaluates the production of two macrophage-specific chemokines, monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha), in the human follicle at ovulation. Blood samples, follicular fluids and follicular cells were collected during menstrual and IVF cycles. Levels of MCP-1 and MIP-1alpha were measured in follicular fluid, blood plasma and cultured media (granulosa, theca and granulosa-lutein cells [GLCs]). Cells were cultured with or without LH, FSH, interleukin (IL)-1alpha, IL-1beta, tumour necrosis factor (TNF) alpha, progesterone or estradiol. The levels of MCP-1 were markedly higher in follicular fluid as compared with blood plasma in both menstrual and IVF cycles. The difference in MCP-1 levels between follicular fluid and plasma in menstrual cycles increased from the follicular phase (three-fold difference) to the late ovulatory phase (25-fold). Levels of MIP-1alpha were low in plasma and follicular fluid of both menstrual and IVF cycles. Theca cells from follicles of menstrual cycles secreted both MCP-1 and MIP-1alpha under basal conditions, and the secretion was increased by addition of IL-1beta (MCP-1 and MIP-1alpha) and IL-1alpha (MCP-1). GLCs secreted MCP-1 under basal conditions and also MIP-1alpha after IL-1beta stimulation. The macrophage-specific chemokine MCP-1 is highly expressed and is induced by IL-1 in the theca layer of the human follicle at ovulation.

Expression and one-step ion-exchange purification of (AAR)IL-8 (human IL-8 receptor antagonist)

Interleukin-8 (IL-8) is C-X-C chemokine, which is produced by a variety of cells. IL-8 plays an important role in the inflammatory response and may be a therapeutic target for some inflammatory diseases. To develop an IL-8 receptor antagonist, (AAR)IL-8 (IL-8 receptor antagonist) was constructed and successfully expressed in Escherichia coli. (AAR)IL-8 could be easily purified by one-step SP-Sepharose fast flow column after the lysate of recombinant bacterial cells was heated at 70 degrees C for 10 min. The purity of (AAR)IL-8 is more than 95%. This purification process resulted in final purified yields of 4.29 mg (AAR)IL-8/g cell paste. In addition, the purified (AAR)IL-8 can significantly inhibit the chemotaxis that was induced by human IL-8 in vitro and in vivo. These results showed that this purification process is very simple and effective. It could be easily amplified at a larger scale. (AAR)IL-8 might find use as a new therapeutic IL-8 receptor antagonist for some acute and chronic inflammatory diseases.

All-trans-retinoic acid induces interleukin-8 via the nuclear factor-kappaB and p38 mitogen-activated protein kinase pathways in normal human keratinocytes

Retinoic acid derivatives have been used successfully for the treatment of various dermatoses, such as psoriasis; however, topical application of these compounds often elicits skin irritation. We hypothesized that this irritation was as a result of the local production of interleukin-8 (IL-8). To test this hypothesis, we investigated whether all-trans-retinoic acid (ATRA) induced IL-8 production in normal human keratinocytes. Stimulation with 10(-7) M ATRA enhanced IL-8 mRNA expression and induced IL-8 production. We also studied the intracellular signaling mechanisms of ATRA-induced IL-8 production in keratinocytes. ATRA increased the expression of RelA (p65), RelB, nuclear factor (NF)-kappaB2 (p52), and NF-kappaB1 (p50), and elevated the DNA-binding activity of p65 and phosphorylation of inhibitor kappaB (IkappaB) alpha. Introduction of a dominant-negative mutant of IkappaBalpha completely abolished ATRA-induced IL-8 production, which indicates that this process is NF-kappaB-dependent. We also studied the role of the p38 mitogen-activated protein kinase (MAPK) pathway in this phenomenon. ATRA phosphorylated the p38 MAPK, and SB202180 inhibited ATRA-induced IL-8 production, which indicates that the p38 MAPK is also involved in ATRA-induced IL-8 production. In summary, ATRA induces IL-8 production in both NF-kappaB- and p38 MAPK-dependent manners in normal human keratinocytes.

Increased CXCL8 (IL-8) expression in Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic inflammatory disease of the CNS which is characterized by large mononuclear cell infiltration and significant demyelination. CXCL8 is a chemo-attractant for both neutrophils and monocytes and triggers their firm adhesion to endothelium. In this study, we demonstrate that serum CXCL8 and CXCL8 secretion from PBMCs are significantly higher in untreated MS patients compared to controls and are significantly reduced in MS patients receiving interferon-beta1a therapy. We suggest that CXCL8 may serve as a marker of monocyte activity in MS and may play a role in monocyte recruitment to the CNS.

Importance of respiratory viruses in acute otitis media

Acute otitis media is usually considered a simple bacterial infection that is treated with antibiotics. However, ample evidence derived from studies ranging from animal experiments to extensive clinical trials supports a crucial role for respiratory viruses in the etiology and pathogenesis of acute otitis media. Viral infection of the upper respiratory mucosa initiates the whole cascade of events that finally leads to the development of acute otitis media as a complication. The pathogenesis of acute otitis media involves a complex interplay between viruses, bacteria, and the host's inflammatory response. In a substantial number of children, viruses can be found in the middle-ear fluid either alone or together with bacteria, and recent studies indicate that at least some viruses actively invade the middle ear. Viruses appear to enhance the inflammatory process in the middle ear, and they may significantly impair the resolution of otitis media. Prevention of the predisposing viral infection by vaccination against the major viruses would probably be the most effective way to prevent acute otitis media. Alternatively, early treatment of the viral infection with specific antiviral agents would also be effective in reducing the occurrence of acute otitis media.

Pathophysiological roles of interleukin-8/CXCL8 in pulmonary diseases

Fifteen years have passed since the first description of interleukin (IL)-8/CXCL8 as a potent neutrophil chemotactic factor. Accumulating evidence has demonstrated that various types of cells can produce a large amount of IL-8/CXCL8 in response to a wide variety of stimuli, including proinflammatory cytokines, microbes and their products, and environmental changes such as hypoxia, reperfusion, and hyperoxia. Numerous observations have established IL-8/CXCL8 as a key mediator in neutrophil-mediated acute inflammation due to its potent actions on neutrophils. However, several lines of evidence indicate that IL-8/CXCL8 has a wide range of actions on various types of cells, including lymphocytes, monocytes, endothelial cells, and fibroblasts, besides neutrophils. The discovery of these biological functions suggests that IL-8/CXCL8 has crucial roles in various pathological conditions such as chronic inflammation and cancer. Here, an overview of its protein structure, mechanisms of production, and receptor system will be discussed as well as the pathophysiological roles of IL-8/CXCL8 in various types of lung pathologies.

Macrophages in human reproductive tissues contain luteinizing hormone/chorionic gonadotropin receptors

PROBLEM

To determine whether macrophages in human reproductive tissues contain luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptor mRNA and receptor protein that can bind 125I-hCG.

METHOD OF STUDY

Macrophages isolated from term pregnancy human decidua were used for LH/hCG receptor detection by in situ hybridization for receptor mRNA and immunocytochemistry for a macrophage marker, CD68, performed alone and in combination, reverse transcription-nested polymerase chain reaction, Western and ligand blotting. The LH/hCG receptor presence in macrophages in late luteal phase human endometria and corpora lutea was determined by sequential performance of in situ hybridization and immunocytochemistry.

RESULTS

The macrophages present in term pregnancy human decidua and late luteal phase human endometria and corpora lutea contain LH/hCG receptors.

CONCLUSIONS

This is the first demonstration of macrophages present in human reproductive tissues containing LH/hCG receptors. The receptor presence suggests that LH and hCG may regulate macrophage functions in gonadal as well as in non-gonadal target tissues.

Addition of a 2-month low-dose course of levofloxacin to long-term erythromycin therapy in sinobronchial syndrome

BACKGROUND

We previously reported that a 6-month low-dose course of ofloxacin combined with long-term low-dose erythromycin therapy (EM therapy) was superior to EM therapy alone for sinobronchial syndrome (SBS), especially during the initial 2 months of treatment. However, there was no data as to whether discontinuation of low-dose ofloxacin after 2 months results in symptom relapse. This study was designed to clarify this issue.

METHODOLOGY

Twenty-three patients with SBS received a 2-month course of levofloxacin (LVFX) therapy (100 mg once a day) concurrent with a 6-month course of EM therapy (200 mg three times a day) (group A). Eighteen other patients were given the EM therapy alone (group B). Clinical parameters, including quantity of morning sputum, were recorded in a daily symptom diary, and reviewed by each doctor in charge at 2-4 week intervals.

RESULTS

The quantity of morning sputum decreased more rapidly in group A than in group B. No relapse of symptoms was recognized after discontinuation of LVFX in group A.

CONCLUSIONS

A 2-month low-dose course of LVFX in conjunction with long-term EM therapy may be efficacious for the treatment of SBS, as evidenced by rapid improvement of expectoration without any relapse after LVFX discontinuation.

Secretion of monocyte chemoattractant protein-1 by endothelial cells of the bovine corpus luteum: regulation by cytokines but not prostaglandin F2alpha

Information regarding the regulation of monocyte chemoattractant protein-1 (MCP-1) in regression of the corpus luteum (CL) is limited. This study tested the hypothesis that endothelial cells derived from bovine CL are a source of MCP-1, and that proinflammatory cytokines, prostaglandin F2alpha (PGF2alpha), and progesterone regulate MCP-1 expression. Endothelial cells were treated without (Control) or with PGF2alpha (1 micro M), TNFalpha (100 ng/ml), interferon-gamma (IFNgamma, 200 IU/ml), and TNFalpha + IFNgamma for 24 and 48 h in the absence or presence of progesterone (P4, 250 ng/ml). Increases in MCP-1 mRNA and protein were observed in response to TNFalpha within 24 and 48 h of culture, respectively (P < 0.05). Interferon-gamma stimulated (P < 0.05) both MCP-1 mRNA and protein after 24 h of culture, and this effect was also sustained through 48 h of culture (P < 0.05). Cotreatment of cultures with TNFalpha + IFNgamma lead to further increases (P < 0.05) in MCP-1 in both 24- and 48-h cultures. Surprisingly, neither PGF2alpha nor P4 affected MCP-1 production. Subsequent experiments revealed that the endothelial cells lacked prostaglandin F2alpha receptor mRNA, and the MAPK pathway, although present and responsive to growth factor stimulation, was unresponsive to PGF2alpha stimulation. In summary, endothelial cells derived from bovine CL respond to TNFalpha and IFNgamma stimulation with an increase in MCP-1 secretion. In contrast, neither PGF2alpha nor P4 directly influenced endothelial expression of MCP-1. These results suggest that cytokines stimulate the synthesis of MCP-1 observed during PGF2alpha-induced luteal regression.

Ammonia and Alzheimer's disease

Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder. Behavioural, cognitive and memory dysfunctions are characteristic symptoms of AD. The formation of amyloid plaques is currently considered as the key event of AD. Other histological hallmarks of the disease are the formation of fibrillary tangles, astrocytosis, and loss of certain neuronal systems in cortical areas of the brain. A great number of possible aetiologic and pathogenetic factors of AD have been published in the course of the last two decades. Among the toxic factors, which have been considered to contribute to the symptoms and progression of AD, ammonia deserves special interest for the following reasons: (a) Ammonia is formed in nearly all tissues and organs of the vertebrate organism; it is the most common endogenous neurotoxic compounds. Its effects on glutamatergic and GABAergic neuronal systems, the two prevailing neuronal systems of the cortical structures, are known for many years. (b) The impairment of ammonia detoxification invariably leads to severe pathology. Several symptoms and histologic aberrations of hepatic encephalopathy (HE), of which ammonia has been recognised as a pathogenetic factor, resemble those of AD. (c) The excessive formation of ammonia in the brains of AD patients has been demonstrated, and it has been shown that some AD patients exhibit elevated blood ammonia concentrations. (d) There is evidence for the involvement of aberrant lysosomal processing of beta-amyloid precursor protein (beta-APP) in the formation of amyloid deposits. Ammonia is the most important natural modulator of lysosomal protein processing. (e) Inflammatory processes and activation of microglia are widely believed to be implicated in the pathology of AD. Ammonia is able to affect the characteristic functions of microglia, such as endocytosis, and cytokine production. Based on these facts, an ammonia hypothesis of AD has first been suggested in 1993. In the present review old and new observations are discussed, which are in support of the notion that ammonia is a factor able to produce symptoms of AD and to affect the progression of the disease.

A novel pathway for nickel-induced interleukin-8 expression

Inhalation of particulate nickel subsulfide (Ni3S2) causes chronic active inflammation and fibrosis of the lungs. However, the mechanisms for these effects are not well understood. Therefore, cell culture experiments with BEAS-2B human airway epithelial cells were conducted to test the hypothesis that exposure to non-cytotoxic levels of Ni3S2 induces expression of inflammatory cytokines such as interleukin-8 (IL-8). Exposure to Ni3S2 for 48 h was required to significantly increase IL-8 protein levels. Transcriptional stimulation of IL-8 mRNA levels preceded the increase in protein. Transient exposure to soluble nickel sulfate failed to increase IL-8 mRNA. Transfection with truncated IL-8 promoter constructs linked to the luciferase gene demonstrated that nickel-induced IL-8 transcription required -272 bp of the promoter relative to the transcriptional start site. A -133-bp construct, containing cytokine and hypoxia-sensitive AP-1, NF-IL6, and NF-kappaB sites, was insufficient for induction by nickel. Transfection with a dominant negative AP-1 construct or mutation of the AP-1, GATA, or C/EBP sites in the -272-bp IL-8 promoter construct blocked induction by nickel. Inhibiting ERK, phosphatidylinositol 3-kinase, but not p38 kinase, diacylglycerol kinase, or hypoxia-inducible factor-1alpha, attenuated nickel induction of IL-8. These studies indicate that nickel induced IL-8 transcription through a novel pathway that requires both AP-1 and non-traditional transcription factors.

Age-related differences in cell-specific cytokine production by acutely ill Malawian patients

Age-related changes in human cell-specific cytokine responses to acute illness have not been well examined. We therefore evaluated age-related differences in T, B and natural killer (NK) peripheral blood lymphocyte cytokine responses of 309 acutely ill hospitalized people in Malawi, Africa, < 1 month-61 years of age. We used four-colour flow cytometry and performed Wilcoxon rank sum and Kruskal-Wallis tests, Pearson (rp) and Spearman (rs) correlations, and linear and logistic regression analyses to control for human immunodeficiency virus infection (HIV) status, the percentages of lymphocytes expressing CD4, and the nature of the acute infection. The percentages of CD8- and CD8+ T cells producing induced IL-8 decreased with age (rs = -0.44 and -0.53). The percentages of T cells producing TNF-alpha were higher, and the percentages producing IL-10 were lower, in those > or =13 than those < 13 years old (medians: 17.7 versus 10.5 and 1.4 versus 3.0, respectively). The percentages of CD8- T cells producing IFN-gamma were higher and stable in those > or =1 year old compared to infants (medians: 23.5 versus 10.4); the percentages of NK producing IFN-gamma were higher post-infancy and then declined to relatively low levels with increasing age. The percentages of T cells producing IL-2 were highest in those 5- <31 years old (median 5.6) and lowest in those > or =31 years old (median 1.9). The ratios of the percentages of T cells producing IL-4 to those producing IL-8 and to those producing IL-10 both increased with age. These data suggest that innate immunity, represented by NK IFN-gamma production, dominates in early life. A number of shifts occur after infancy and before adolescence, including a proinflammatory shift from IL-8 to TNF-gamma and a type 2 shift from IL-10 to IL-4 dominance. These findings suggest distinct age-related differences in the human response to acute illness and may be useful in directing future efforts at immunomodulatory therapies.

Profiles of pro-inflammatory cytokines in the serum of rabbits after experimentally induced acute pancreatitis

In a recent study we have demonstrated that interleukin 8 (IL-8) and tumour necrosis factor alpha (TNF-alpha) serum levels correlate positively with the severity of acute pancreatitis (AP), induced by bile acid injected into the pancreatic duct of rabbits. In this article we describe the effect of an IL-10 analogue IT9302 and a monoclonal anti-IL-8 (mon. IL-8) antibody on the content of several pro-inflammatory cytokines in the serum of rabbits, after induction of AP. We found that the serum content of inflammatory cytokines IL-8, IL-1beta, TNF-alpha and monocyte chemoattractant protein 1 (MCP-1) are increased during AP. Injection of IT9302 or mon. IL-8 antibody, diminish the concentration of these cytokines in the serum, with the exception that mon. IL-8 antibody actually increased the circulating level of MCP-1. In addition, intravenous administration of IT9302 increased the serum levels of IRAP, an IL-1beta receptor antagonistic cytokine. Furthermore, intravenous injection of mon. IL-8 antibody increased serum levels of IL-4. It can be concluded that both the human IL-10 analogue IT9302 and mon. IL-8 antibody are able to alter the pro-inflammatory cytokine levels in rabbits suffering from experimentally induced AP.

Enhanced contact hypersensitivity in human monocyte chemoattractant protein-1 transgenic mouse

Monocyte chemoattractant protein (MCP)-1 is a chemotactic cytokine for monocytes, memoryT cells and dendritic cells (DC). However, the precise role of MCP-1 in a variety of immunological responses remains unclear. In the present study, we analyzed contact hypersensitivity (CHS) using human MCP-1 transgenic mice (hMCP-1Tgm) that constitutively produce high levels of hMCP-1 in the sera. Following 2,4-dinitrofluorobenzene (DNFB) sensitization, enhancement of CHS was demonstrated in Tgm as compared with that in non-Tgm. Anti-hMCP-1 antibodies significantly inhibited the CHS in Tgm. A prominent accumulation of B7-1+I-Ad+ Langerhans' cells (LC) bearing haptens was detected in draining lymph nodes (DLN) of Tgm 24 h after DNFB or fluorescein isothiocyanate (FITC) sensitization. Similar results were obtained with BALB/c mice administrated recombinant (r) hMCP-1. Langerhans' cells (LC) in the epidermal sheets of Tgm increased in size and expressed high levels of I-Ad and B7-1 12 h after FITC application compared with those of non-Tgm. After 18 h, the number of LC in the epidermis was reduced in Tgm. It was also shown that the B7-1 expression on LC of BALB/c mice was augmented after culture with rhMCP-1. These findings demonstrate that MCP-1 not only accelerates LC migration from epidermis into the DLN after sensitization with haptens but also up-regulates the I-Ad and B7-1 expressions, which results in the enhanced T cell activation and CHS.

Characteristics of the human ocular surface epithelium

An appreciation of the biological characteristics of the human ocular surface epithelium affords us a great insight into the physiology of the human ocular surface in health and disease. Here, we review five important aspects of the human ocular surface epithelium. First, we recognize the discovery of corneal epithelial stem cells, and note how the palisades of Vogt have been suggested as a clinical marker of their presence. Second, we introduce the concept of the gene expression profile of the ocular surface epithelium as arrived at using a new strategy for the systematic analysis of active genes. We also provide a summary of several genes abundantly or uniquely expressed in the human corneal epithelium, namely clusterin, keratin 3, keratin 12, aldehyde dehydrogenase 3 (ALDH3), troponin-I fast-twitch isoform, ssig-h3, cathepsin L2 (cathepsin V), uroplakin Ib, and Ca(2+)-activated chloride channel. Genes related to limbal and conjunctival epithelia are also described. Third, we touch upon the genetic abnormalities thought to be involved with epithelial dysfunction in Meesmann's dystrophy, gelatinous drop-like corneal dystrophy, and the ssig-h3-mutated corneal dystrophies. Fourth, we provide an update regarding the current state of knowledge of the role of cytokines, growth factors and apoptosis in relation to ocular surface homeostasis and tissue reconstruction; the main factors being epidermal growth factor (EGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), transforming growth factor-ss (TGF-ss), and some inflammatory cytokines. Fifth, corneal epithelial barrier function and dysfunction as measured by fluorophotometry is remarked upon, with an explanation of the FL-500 fluorophotometer and its ability to detect corneal epithelial dysfunction at a subclinical level. The research described in this review has undoubtedly generated a complete understanding of corneal epithelial pathophysiology-an understanding that, directly or indirectly, has helped advance the development of new therapeutic modalities for ocular surface reconstruction.

Cytokines and malaria parasitemia

The balance between pro- and antiinflammatory cytokines may be important in malaria presentation and outcome. Malaria tends to be more severe in children than in adults, presumably because partial immunity develops with age. However, the full nature of, and age-related differences in, anti-malarial immunity are unknown. We compared: (1) serum and cell-specific cytokines of patients with acute malaria to those of patients with other acute illnesses and to those of healthy adults and (2) the cytokine responses of parasitemic children and parasitemic adults. Flow cytometry was done on the peripheral blood mononuclear cells of 148 hospitalized children, 161 febrile hospitalized adults, and 20 healthy adults in Malawi, Africa, a malaria-endemic country. Serum cytokines were also assessed for 80 of these patients. Thirty-eight participants were parasitemic with Plasmodium falciparum. Serum interleukin (IL)-10 (an antiinflammatory, immunoregulatory, and type 2 cytokine) levels were higher in malaria patients than in other patients (medians 502 pg/mL vs 16 pg/mL, P = 0.002), and the percentages of various lymphocyte populations making IL-6 (a proinflammatory, type 2 cytokine regulating iron distribution) were lower in malaria patients than in other patients (e.g., for spontaneous production by children's CD8(+) T cells: medians 1.4% vs 33.1%, P = 0.004). For adult patients, the percentages of lymphocytes spontaneously making IL-4 (a type 2 cytokine) were significantly lower in those with malaria than in those without malaria (medians 0.9% vs 2.1%, P = 0.005). The percentages of monocytes spontaneously making IL-8 (a chemotactic, proinflammatory chemokine) were higher in parasitemic children than in parasitemic adults (medians 5.8% vs 1.7%, P = 0.003). A number of cellular proinflammatory, type 1 parameters were significantly higher in all children (with or without malaria) than in all adults; these included the percentages of various lymphocyte populations making IL-6, both IL-6 and interferon-gamma, or IL-8. These data support the importance of IL-10 in malaria parasitemia. Given the lack of an IL-4 (type 2) response, IL-10's primary role may be immunoregulatory rather than type 2 in nature. In this study, the immune response to malaria was more proinflammatory in children than in adults. This difference, if corroborated by other studies, could be related to malaria's greater severity in children.

Hepatitis C virus nonstructural 5A protein induces interleukin-8, leading to partial inhibition of the interferon-induced antiviral response

Hepatitis C virus (HCV), a major cause of liver disease worldwide, is frequently resistant to the antiviral alpha interferon (IFN). The HCV nonstructural 5A (NS5A) protein has been implicated in HCV antiviral resistance in many studies. NS5A antagonizes the IFN antiviral response in vitro, and one mechanism is via inhibition of a key IFN-induced enzyme, the double-stranded-RNA-activated protein kinase (PKR). In the present study we determined if NS5A uses other strategies to subvert the IFN system. Expression of full-length NS5A proteins from patients who exhibited a complete response (FL-NS5A-CR) or were nonresponsive (FL-NS5A-NR) to IFN therapy in HeLa cells had no effect on IFN induction of IFN-stimulated gene factor 3 (ISGF-3). Expression of mutant NS5A proteins lacking 110 (NS5A-DeltaN110), 222 (NS5A-DeltaN222), and 334 amino-terminal amino acids and mutants lacking 117 and 230 carboxy-terminal amino acids also had no effect on ISGF-3 induction by IFN. Expression of FL-NS5A-CR and FL-NS5A-NR did not affect IFN-induced STAT-1 tyrosine phosphorylation or upregulation of PKR and major histocompatibility complex class I antigens. However, NS5A expression in human cells induced interleukin 8 (IL-8) mRNA and protein, and this effect correlated with inhibition of the antiviral effects of IFN in an in vitro bioassay. NS5A induced transcription of a reporter gene driven by the IL-8 promoter, and the first 133 bp of the IL-8 promoter made up the minimal domain required for NS5A transactivation. NS5A-DeltaN110 and NS5A-DeltaN222 stimulated the IL-8 promoter to higher levels than did the full-length NS5A protein, and this correlated with increased nuclear localization of the proteins. Additional mutagenesis of the IL-8 promoter suggested that NF-kappaB and AP-1 were important in NS5A-DeltaN222 transactivation in the presence of tumor necrosis factor alpha and that NF-IL-6 was inhibitory to this process. This study suggests that NS5A inhibits the antiviral actions of IFN by at least two mechanisms and provides the first evidence for a biological effect of the transcriptional activity of the NS5A protein. During HCV infection, viral proteins may induce chemokines that contribute to HCV antiviral resistance and pathogenesis.