Interleukin-8 (IL-8) and monocyte chemotactic and activating factor (MCAF/MCP-1), chemokines essentially involved in inflammatory and immune reactions

Semaphorin 7A on keratinocytes induces interleukin-8 production by monocytes

BACKGROUND

Semaphorin 7A (Sema7A) expressed on activated T cells stimulates cytokine production in monocytes through its receptor, α1β1 integrin.

OBJECTIVE

To study the significance of Sema7A expressed on keratinocytes in skin inflammation where interaction between keratinocytes and β1-integrin expressing inflammatory cells, such as monocytes, takes place.

METHODS

The regulation of Sema7A expression on keratinocytes by various cytokines was studied by flow cytometry and immunoblot. β1-integrin expressing human monocyte cell line, THP-1 cells, were co-cultured with paraformaldehyde-fixed normal human epidermal keratinocytes (NHK) and IL-8 production by THP-1 cells was studied. The significance of β1-integrin or Sema7A within this cell interaction was examined by the experiments using β1-integrin blocking antibody or Sema7A siRNA.

RESULTS

IFN-γ and TNF-α slightly increased Sema7A expression, while IL-4 decreased it. Among cytokines tested, TGF-β1 most strikingly increased the Sema7A expression on NHK. When NHK was stimulated by TGF-β1, paraformaldehyde-fixed, and co-cultured with THP-1 cells, IL-8 production by THP-1 cells was increased compared to THP-1 cells only. When THP-1 cells were pretreated with β1-integrin blocking antibody, this increase in IL-8 production by THP-1 cells was inhibited. Likewise, when NHK were pretreated with Sema7A siRNA before fixation and co-cultured with THP-1 cells, increase in IL-8 production by THP-1 cells was inhibited.

CONCLUSION

Our results suggest that Sema7A on keratinocytes and β1-integrin on monocytes contribute to monocyte activation by keratinocytes within skin inflammation, such as psoriasis or wound.

Interferon-λ in HCV Infection and Therapy

Chronic infection with hepatitis C virus (HCV) is associated with significant liver disease and is therefore an important public health problem. The current standard-of-care therapy for chronic HCV infection consists of a combination of pegylated (PEG) interferon (IFN)-α and ribavirin. Although this therapy effectively generates a sustained viral response in approximately half of treated individuals, it is associated with significant hematological and neurological side effects. A new family of IFN-related proteins (IFN-λ1, 2, and 3; or alternately, IL-29, 28A, 28B, respectively) possesses properties that may make these cytokines superior to PEG-IFN-α for HCV therapy. Genetic studies have also implicated these proteins in both the natural and therapy-induced resolution of HCV infection. This review summarizes the basic aspects of IFN-λ biology, the potential role of these cytokines in HCV infection, and the outlook for their therapeutic application.

Monocyte chemotactic protein-1 (MCP-1/CCL2) is associated with prostatic growth dysregulation and benign prostatic hyperplasia

BACKGROUND

Chronic inflammation is commonly observed in benign prostate hyperplasia (BPH), and prostate tissue often contains increased inflammatory infiltrates, including T cells and macrophages. Cytokines are not only key mediators of inflammation but may also play important roles in the initiation and progression of BPH.

METHODS

In order to determine what cytokines might be involved in prostatic enlargement, expressed prostatic secretions (EPS) from ex vivo prostates were analyzed by human cytokine antibody microarray and ELISA. Prostate epithelial cells (PrEC) and prostate stromal cells (PrSC) were used for ELISA, proliferation, and Western blot assays.

RESULTS

Monocyte chemotactic protein-1 (MCP-1/CCL2) was one of the most elevated proteins in secretions from large prostate glands. PrSC were found to secrete MCP-1; Western blotting showed that both PrSC and PrEC express the MCP-1 receptor CCR2 which by RT-PCR was the CCR2b isoform. Proliferation assays showed that MCP-1 stimulates the proliferation of PrEC, but not PrSC, and that a specific MCP-1 antagonist (RS102895) suppressed this effect. Conditioned medium from PrSC stimulated the proliferation of PrEC as well, an effect completely inhibited by both RS102895 and a neutralizing anti-MCP-1 monoclonal antibody. The inflammatory cytokines interleukin (IL)-1 beta, interferon-gamma, and IL-2 enhanced the secretion of MCP-1 from PrEC and PrSC. In addition, MCP-1 levels in EPS correlated with mRNA levels of the macrophage marker CD68 in the same secretions.

CONCLUSIONS

The cytokine MCP-1, of apparent prostatic stromal cell origin, may play an important role in prostatic enlargement and BPH, and is a candidate biomarker for these pathologic processes.

Increased CCL2 expression and macrophage/monocyte migration during microbicide-induced vaginal irritation

Despite availability of successful prevention strategies, HIV continues to spread at alarming rates, especially among women in developing countries. Vaginal microbicides offer a promising approach for blocking transmission of HIV when condom use cannot be negotiated with male partners. A major problem in the development of vaginal microbicides is chemically induced vaginal irritation, which can enhance the risk of HIV transmission. Evaluation of vaginal irritation prior to clinical trials typically uses an expensive and animal-intensive rabbit vaginal irritation model, which could be supplemented by measuring additional inflammatory biomarkers. We studied several immunological parameters as potential biomarkers of vaginal irritation, using the spermicides nonoxynol-9 and benzalkonium chloride as test microbicides. We measured amounts of cytokines, as well as inflammatory cells, in vaginal tissue lysates and on the vaginal surface. We observed that treatment with the selected microbicides increases quantities of the inflammatory cytokines interleukin-1beta, CXCL8, and CCL2 in the vaginal tissue parenchyma, and of CCL2 on the vaginal surface. This observation was correlated with increases in macrophages in the vaginal parenchyma. We suggest that measurements of CCL2 and macrophages can serve as new inflammatory biomarkers to evaluate the safety of promising novel microbicides for prevention of HIV.

Mammary gene expression profiles during an intramammary challenge reveal potential mechanisms linking negative energy balance with impaired immune response

Our objective was to compare mammary tissue gene expression profiles during a Streptococcus uberis (S. uberis) mastitis challenge between lactating cows subjected to dietary-induced negative energy balance (NEB; n = 5) and cows fed ad libitum to maintain positive energy balance (PEB; n = 5) to better understand the mechanisms associated with NEB and risk of mastitis during the transition period. The NEB cows were feed-restricted to 60% of calculated net energy for lactation requirements for 7 days, and cows assigned to PEB were fed the same diet for ad libitum intake. Five days after feed restriction, one rear mammary quarter of each cow was inoculated with 5,000 cfu of S. uberis (O140J). At 20 h postinoculation, S. uberis-infected mammary quarters from all cows were biopsied for RNA extraction. Negative energy balance resulted in 287 differentially expressed genes (DEG; false discovery rate ≤ 0.05), with 86 DEG upregulated and 201 DEG downregulated in NEB vs. PEB. Canonical pathways most affected by NEB were IL-8 signaling (10 genes), glucocorticoid receptor signaling (13), and NRF2-mediated oxidative stress response (10). Among the genes differentially expressed by NEB, cell growth and proliferation (48) and cellular development (36) were the most enriched functions. Regarding immune response, HLA-A was upregulated due to NEB, whereas the majority of genes involved in immune response were downregulated (e.g., AKT1, IRAK1, MAPK9, and TRAF6). This study provided new avenues for investigation into the mechanisms relating NEB and susceptibility to mastitis in lactating dairy cows.

Iodide-induced chemokines and genes related to immunological function in cultured human thyroid follicles in the presence of thyrotropin

BACKGROUND

It is well known that iodide exacerbates thyroid function in subclinical hypothyroid patients with autoimmune thyroiditis. To investigate the immunological mechanism of iodine-induced thyroid dysfunction, we studied the effect of iodide in cultured human thyroid follicles, which respond to physiological concentrations of human thyrotropin (TSH) (0.3-10 microU/mL) and maintain the Wolff-Chaikoff effect.

MATERIALS AND METHODS

Thyroid follicles obtained from Graves' patients at subtotal thyroidectomy were precultured in medium containing 0.5% fetal calf serum and 10(-8) M iodide for 5 days, and then cultured with the medium containing bovine TSH (30 microU/mL) and low (10(-8)M) or high (10(-5)M) concentrations of iodide. After 3-72 hours of culture, the effect of iodide on thyroid cell mRNA expression was analyzed by microarray and reverse transcriptase-polymerase chain reaction.

RESULTS

After 48 hours of culture, iodide nearly doubled the mRNA expression levels of the immunity-associated genes (intercellular adhesion molecule-1, transforming growth factor beta 1-induced protein, early growth response gene 1, guanylate-binding protein 1, and annexin A1) and decreased the mRNA expression of sodium-iodide symporter to less than 20%. Further, the mRNA expression levels of chemokines (CCL2, CXCL8, and CXCL14) increased nearly twofold, whereas their receptors did not show any significant response. Real-time polymerase chain reaction analyses confirmed that iodide increased the mRNA expression levels of these genes in a time- and concentration-dependent manner. Immunohistochemical studies revealed that the chemokines were expressed mainly in the thyroid follicular cells in addition to the immune cells. The iodide-induced increase in CCL2 was greater in thyroid follicles obtained from thyroid gland that had been moderately infiltrated with the immunocompetent cells.

CONCLUSION

We have demonstrated that iodide stimulates thyroid follicular cells to produce chemokines, particularly CCL2, CXCL8, and CXCL14. These chemokines and intercellular adhesion molecule-1 would attract immunocompetent cells into thyroid gland. These in vitro findings suggest that iodide at high concentrations may induce thyroid dysfunction through not only biochemical but also immunological mechanisms, particularly in patients with autoimmune thyroid disorders.

A synthetic curcuminoid derivative inhibits nitric oxide and proinflammatory cytokine synthesis

Curcumin is a highly pleiotropic molecule with significant regulatory effects upon inflammation and inflammatory related diseases. However curcumin has one major important limitation in which it has poor bioavailability. Design of synthetic structural derivatives of curcumin is but one approach that has been used to overcome its poor bioavailability while retaining, or further enhancing, its drug-like effects. We have synthesized a series of curcumin analogues and describe the effects of 2,6-bis-4-(hydroxyl-3-methoxy-benzylidine)-cyclohexanone or BHMC upon nitric oxide and cytokine synthesis in cellular models of inflammation. BHMC showed a significant dose-response inhibitory action upon the synthesis of NO and we have shown that this effect was due to suppression of both iNOS gene and enzyme expression without any effects upon scavenging of nitrite. We also demonstrated that BHMC has a very minimal effect upon iNOS activity with no effect at all upon the secretion of PGE(2) but has a strong inhibitory effect upon MCP-1 and IL-10 secretion and gene expression. Secretion and gene expression of TNF-alpha and IL-6 were moderately inhibited whereas IL-8 and IL-1beta were not altered. We conclude that BHMC selectively inhibits the synthesis of several inflammatory mediators. BHMC should be considered a promising drug lead for preclinical and further pharmacological studies.

Evaluation of efficacy, biodistribution, and inflammation for a potent siRNA nanoparticle: effect of dexamethasone co-treatment

Despite recent progress, systemic delivery remains the major hurdle for development of safe and effective small inhibitory RNA (siRNA)-based therapeutics. Encapsulation of siRNA into liposomes is a promising option to overcome obstacles such as low stability in serum and inefficient internalization by target cells. However, a major liability of liposomes is the potential to induce an acute inflammatory response, thereby increasing the risk of numerous adverse effects. In this study, we characterized a liposomal siRNA delivery vehicle, LNP201, which is capable of silencing an mRNA target in mouse liver by over 80%. The biodistribution profile, efficacy after single and multiple doses, mechanism of action, and inflammatory toxicity are characterized for LNP201. Furthermore, we demonstrate that the glucocorticoid receptor (GR) agonist dexamethasone (Dex) inhibits LNP201-induced cytokine release, inflammatory gene induction, and mitogen-activated protein kinase (MAPK) phosphorylation in multiple tissues. These data present a possible clinical strategy for increasing the safety profile of siRNA-based drugs while maintaining the potency of gene silencing.

Human monocyte activation by biologic and biodegradable meshes in vitro

BACKGROUND

Inflammation and wound healing play critical roles in the integration of biologic and biodegradable meshes (BMs) at hernia repair sites. Monocytes/macrophages (M/MØs) are key cells controlling inflammation and wound healing. These cells release inflammatory cytokines and growth factors such as interleukin (IL)-1beta, IL-6, IL-8, and vascular endothelial growth factor (VEGF) upon activation. Although BMs have been increasingly used in hernia repairs worldwide, to date, investigations of inflammatory responses to various BMs have been limited.

METHODS

Mesh samples of three acellular human dermis-derived biologic meshes (AlloDerm, AlloMax, FlexHD) and one biodegradable synthetic mesh (Bio-A) were placed in 96-well plates. Human peripheral blood mononuclear cells (PBMCs) were isolated from six healthy subjects, added to each well, and incubated for 7 days. Culture supernatants were assayed for IL-1beta, IL-6, IL-8, and VEGF levels using a multiplex bead-base immunoassay system (Bio-Plex).

RESULTS

All four meshes induced cytokine expression from activated M/MØs to varying degrees in vitro. FlexHD induced significantly more IL-1beta (2,591 pg/ml) than AlloMax (517 pg/ml), AlloDerm (48 pg/ml), or Bio-A (28 pg/ml) (p < 0.001). AlloMax stimulated a significantly greater quantity of IL-6 (38,343 pg/ml) than FlexHD (19,317 pg/ml), Bio-A (191 pg/ml), or AlloDerm (103 pg/ml) (p < 0.05). Interleukin-8 and VEGF displayed trends similar to that of IL-6. There were no significant differences in cytokine production between AlloDerm and Bio-A.

CONCLUSION

This study demonstrated that human macrophages are activated by human dermis-derived biologic and biodegradable meshes in vitro. A wide range of cytokine and growth factor induction was seen among the different mesh products. These differences in M/MØ activation may be related to the proprietary processing technologies of the studied meshes. The study results raise the possibility that these differences in M/MØ activation could indicate varying intensities of inflammation that control integration of different biologic meshes at the sites of hernia repair.

The role of CC chemokine receptor 2 on microglia activation and blood-borne cell recruitment after transient focal cerebral ischemia in mice

The chemokine receptor 2 (CCR2) is involved in inflammatory reactions following cerebral ischemia. Monocyte chemoattractant protein-1 (MCP-1) binds with high affinity to CCR2. MCP-1 is necessary for recruiting blood-borne cells to the injury site whereas it does not affect microglia activation and migration. MCP-1-deficient mice develop smaller infarcts and show a better functional outcome. CCR2-deficient mice also develop smaller infarcts and have a reduced expression of inflammatory cytokines during reperfusion. In the present study we investigated the differential role of inflammatory cells in CCR2-deficient mice, using green fluorescent protein (GFP)-transgenic bone marrow chimeras. After 30 min of transient middle cerebral artery occlusion (MCAO), activation of local microglia was similar in CCR2-deficient animals and their littermate controls over the study period, whereas an influx of GFP-positive cells was diminished in CCR2-deficient mice. Infiltrating macrophages were significantly reduced at day seven in the deficient animals (26.04+/-25.19 cells/mm(2)) compared to control mice (86.83+/-44.41 cells/mm(2), p<0.001). Neutrophils were also significantly reduced in CCR2-deficient mice (83% on day 2, 76% on day 4 and 89% on day 7, p<0.001). A significant reduction of infarct volume in CCR2-deficient animals could not be detected. In this study a clear differentiation of local and blood-borne inflammatory cell reaction after cerebral ischemia could be shown, demonstrating that CCR2-deficiency attenuates hematogenous cell recruitment to the injury site whereas microglia activation and migration is not affected.

Antiinflammatory effects of the ETS factor ERG in endothelial cells are mediated through transcriptional repression of the interleukin-8 gene

ERG (Ets-related gene) is an ETS transcription factor that has recently been shown to regulate a number of endothelial cell (EC)-restricted genes including VE-cadherin, von Willebrand factor, endoglin, and intercellular adhesion molecule-2. Our preliminary data demonstrate that unlike other ETS factors, ERG exhibits a highly EC-restricted pattern of expression in cultured primary cells and several adult mouse tissues including the heart, lung, and brain. In response to inflammatory stimuli, such as tumor necrosis factor-alpha, we observed a marked reduction of ERG expression in ECs. To further define the role of ERG in the regulation of normal EC function, we used RNA interference to knock down ERG. Microarray analysis of RNA derived from ERG small interfering RNA- or tumor necrosis factor-alpha-treated human umbilical vein (HUV)ECs revealed significant overlap (P<0.01) in the genes that are up- or downregulated. Of particular interest to us was a significant change in expression of interleukin (IL)-8 at both protein and RNA levels. Exposure of ECs to tumor necrosis factor-alpha is known to be associated with increased neutrophil attachment. We observed that knockdown of ERG in HUVECs is similarly associated with increased neutrophil attachment compared to control small interfering RNA-treated cells. This enhanced adhesion could be blocked with IL-8 neutralizing or IL-8 receptor blocking antibodies. ERG can inhibit the activity of the IL-8 promoter in a dose dependent manner. Direct binding of ERG to the IL-8 promoter in ECs was confirmed by chromatin immunoprecipitation. In summary, our findings support a role for ERG in promoting antiinflammatory effects in ECs through repression of inflammatory genes such as IL-8.

Vacuum-assisted closure therapy increases local interleukin-8 and vascular endothelial growth factor levels in traumatic wounds

BACKGROUND

Clinical observations are suggesting accelerated granulation tissue formation in traumatic wounds treated with vacuum-assisted closure (VAC). Aim of this study was to determine the impact of VAC therapy versus alternative Epigard application on local inflammation and neovascularization in traumatic soft tissue wounds.

METHODS

Thirty-two patients with traumatic wounds requiring temporary coverage (VAC n = 16; Epigard n = 16) were included. At each change of dressing, samples of wound fluid and serum were collected (n = 80). The cytokines interleukin (IL)-6, IL-8, vascular endothelial growth factor (VEGF), and fibroblast growth factor-2 were measured by ELISA. Wound biopsies were examined histologically for inflammatory cells and degree of neovascularization present.

RESULTS

All cytokines were found to be elevated in wound fluids during both VAC and Epigard treatment, whereas serum concentrations were negligible or not detectable. In wound fluids, significantly higher IL-8 (p < 0.001) and VEGF (p < 0.05) levels were detected during VAC therapy. Furthermore, histologic examination revealed increased neovascularization (p < 0.05) illustrated by CD31 and von Willebrand factor immunohistochemistry in wound biopsies of VAC treatment. In addition, there was an accumulation of neutrophils as well as an augmented expression of VEGF (p < 0.005) in VAC wound biopsies.

CONCLUSION

This study suggests that VAC therapy of traumatic wounds leads to increased local IL-8 and VEGF concentrations, which may trigger accumulation of neutrophils and angiogenesis and thus, accelerate neovascularization.

Cytokine profiling using monocytes/macrophages cultured on common biomaterials with a range of surface chemistries

Cytokines, chemokines, and growth factors were assayed from the supernatants of monocytes and macrophages cultured on common biomaterials with a range of surface chemistries. TNF-alpha, MCP-1, MIP-1alpha, IL-8, IL-6, IL-1beta, VEGF, IL-1ra, and IL-10 were measured from monocyte/macrophage cultures at different stages of activation and differentiation seeded onto polyethylene, polyurethane, expanded polytetrafluoroethylene, polymethyl methacrylate, and a hydrogel copolymer of 2-hydroxyethyl methacrylate, 1-vinyl-2-pyrrolidinone, and polyethylene glycol acrylate in tissue culture polystyrene (TCPS) plates. Empty TCPS wells and organo-tin polyvinyl chloride served as "blanks" and positive controls, respectively. Results showed an overall increase in cytokine, chemokine, and growth factor production as monocytes are activated or differentiated into macrophages and that proinflammatory and anti-wound healing cytokines and chemokines dominate this profile. However, cytokine production was only modestly affected by the surface chemistry of these four stable and noncytotoxic biomaterials.

Effects of synthetic monocyte chemotactic protein-1 fragment 65-76 on neointima formation after carotid artery balloon injury in rats

The effects of the synthetic monocyte chemotactic protein-1 (MCP-1) peptide fragment 65-76 (peptide X) on the development of neointima after balloon injury to the carotid artery were studied. The agent was given i.m. at a dose of 33 microg/kg once daily for 28 days after balloon injury. Animals given peptide showed significant suppression of neointima growth 4 and 7 days after lesioning, as indicated by morphometric analysis of sections of lesioned arteries. On days 14 and 28, there were no significant differences in neointima formation in rats given and not given peptide. Peptide administration was not accompanied by any changes in C-reactive peptide concentrations, leukocyte counts, or the population composition of peripheral blood lymphocytes. Use of synthetic peptide X as an inhibitor of leukocyte migration during angioplasty may, along with traditional treatments, decrease the risk of restenosis.

Interleukin (IL)-1beta stimulates migration and survival of first-trimester villous cytotrophoblast cells through endometrial epithelial cell-derived IL-8

IL-1, secreted by human embryos and trophoblast cells, is important for successful implantation and pregnancy. We previously reported that IL-1beta induced IL-8 production in human endometrial stromal cells (ESCs) and that induction was regulated by substances implicated in implantation. In the present study using human primary cells in culture, we measured IL-1beta-induced production of IL-8 from endometrial epithelial cells (EECs) and ESCs and examined effects of the endometrium-derived IL-8 on migration and number of first-trimester villous cytotrophoblast cells (vCTs). Both basal and IL-1beta-induced IL-8 levels of cell supernatants were much higher in EECs than ESCs. Addition of IL-1beta to EECs increased the chemotactic activity of the supernatants to vCTs, and this effect was suppressed by immunoneutralization with anti-IL-8 antibody. Supernatants of IL-1beta-stimulated EECs yielded significantly higher number of vCTs compared with those of untreated EECs, and the effect was inhibited by IL-8 antibody. These findings suggest that IL-1 promotes implantation by stimulating EECs to produce IL-8, which subsequently induces migration of vCTs and contributes to survival of vCTs.

Altered kinetics of interleukin-6 and other inflammatory mediators during exercise in children with type 1 diabetes

BACKGROUND

Leukocyte mobilization and secretions of cytokines, chemokines, and growth factors in children during exercise are necessary biochemical signals for physiological growth and long-term cardiovascular protection. Because of glycemic instability, altered exercise responses, particularly the proinflammatory cytokine interleukin (IL)-6, may occur in type 1 diabetes mellitus (T1DM) that could influence the onset/progression of diabetic vascular complications. Relatively little is known, however, on most molecular aspects of immunomodulatory adaptation to exercise in diabetic children.

METHODS

We therefore studied 21 children (age, 13.4 +/- 0.3 years; 13 boys/8 girls) with T1DM and 21 age-matched healthy controls during 30 minutes of intense and intermittent cycling exercise. Euglycemia was maintained during and for greater than 90 minutes before exercise; blood samples for IL-6 and other cytokines/chemokines were drawn before, during (every 6 minutes), and after (every 15 minutes) exercise.

RESULTS

In T1DM, exercise-induced IL-6 peak occurred earlier and with greater magnitude than that in controls; an exploratory analysis of additional inflammatory mediators displayed a similarly accelerated/exaggerated pattern in T1DM, including the kinetic profiles of tumor necrosis factor alpha, IL-4, IL-12p70, IL-17, granulocyte-monocyte colony-stimulating factor, monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha, and eotaxin (interferon-inducible protein-10 was the only measured variable essentially indistinguishable between groups).

CONCLUSION

Therefore, during intense and intermittent exercise, significant alterations in the immunologic pattern of inflammatory regulation occurred in children with T1DM as compared with healthy controls. Our findings underscore how the understanding of all the underlying molecular mechanisms is a necessary prerequisite for achieving effective use of exercise and the full manifestation of its health benefits, particularly in understudied populations such as children with T1DM who are at increased risk for cardiovascular complications.

Immune mediators in idiopathic nephrotic syndrome: evidence for a relation between interleukin 8 and proteinuria

The pathogenesis of idiopathic nephrotic syndrome (INS) remains unknown. Several findings suggest a role for the immune system. This study aimed to evaluate immune mediators in INS by measuring plasma and urinary levels of transforming growth factor beta1 (TGF-beta1), monocyte chemoattractant protein-1 (MCP-1/CCL2), regulated on activation normal T-cell expressed and secreted (RANTES/CCL5) and IL-8 (IL-8/CXCL8) in pediatric patients with INS and in age-matched healthy controls. Patients were divided according to their response to corticosteroids: steroid-sensitive (SS, n = 8), or steroid-resistant (SR, n = 24). Immune mediators were also compared in regard with disease activity (relapse and remission). Immune mediators were measured by ELISA. Plasma TGF-beta1 levels in SR patients were approximately 2.8-fold higher than control values (p < 0.05). Urinary IL-8/CXCL8 was 2.9-fold higher in INS patients in relapse (proteinuria >100 mg/m2/24 h) when compared with patients in remission (p < 0.05), and levels had a positive correlation with individual proteinuria values (p < 0.05). Urinary IL-8/CXCL8 was significantly higher in relapsed SR than in SS patients in remission. No changes in MCP-1/CCL2 and RANTES/CCL5 levels were detected. Our findings suggest that IL-8/CXCL8 and TGF-beta1 are involved in the pathogenesis of INS: IL-8/CXCL8 associated with local changes in glomerular permeability and TGF-beta1 could be related to worse response to corticosteroids.

Characterization of interleukin 8 in woodchucks with chronic hepatitis B and hepatocellular carcinoma

The eastern woodchuck, Marmota monax, represents a useful animal model to study hepatitis B virus infection in humans. However, immunological studies in this model have been impeded by a lack of basic information about the components of the immune system such as cytokines and chemokines. To clarify the role(s) of interleukin 8 (IL-8) in chronic hepatitis B and hepatocellular carcinoma (HCC) in the woodchuck model, we cloned and characterized the woodchuck IL-8 cDNA and genomic DNA. Sequence analysis revealed that the organization of the wk-IL-8 gene is similar to that of the human IL-8 gene and consists of four exons and three introns. Woodchuck IL-8 protein exhibits the conserved ELRCXC motif of IL-8 and shows 87, 82, 82 and 79% similarity with rabbit, ovine, bovine and human IL-8 proteins, respectively. The biological activity of wk-IL-8 was demonstrated using neutrophil chemotaxis assays. Wk-IL-8 could be readily detected in both tumor and non-tumor tissues with higher expression in the non-tumor tissues in most cases. The results from this study will facilitate the investigation of IL-8 in the immunopathogenesis of hepadnavirus-related diseases by the woodchuck model.

Genetic polymorphism of MCP-1-2518, IL-8-251 and susceptibility to acute pancreatitis: a pilot study in population of Suzhou, China

AIM

To study the relationship between MCP-1-2518A/G, IL-8-251A/T polymorphism and acute pancreatitis (AP) in the Han population of Suzhou, China.

METHODS

A case-control study was conducted to compare the distribution of genotype and genetic frequency of MCP-1-2518A/G, IL-8-251A/T gene polymorphism among AP (n = 101), including mild AP (n = 78) and severe AP (n = 23) and control healthy individuals (n = 120) with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing, and analyze the relationship between the MCP-1-2518A/G, IL-8-251A/T gene polymorphism and the susceptibility to AP.

RESULTS

Significant differences were found in the distribution of genotype of MCP-1-2518A/G between the healthy control group and mild AP group (chi2 = 32.015, P < 0.001), the same was evident between the healthy control group and severe AP group (chi2 = 12.932, P < 0.05) in Suzhou. However, no difference of genotypic distribution was noted between MAP and SAP (chi2 = 0.006, P = 0.997). The genetic frequencies of G allele in mild AP were 72.4% (113/156) and 76.1% (35/46) in severe AP, both were higher than the controls, 47.1% (113/240) (chi2 = 24.804; P < 0.001, and chi2 = 13.005; P < 0.001), but no difference was found between severe AP and mild AP (chi2 = 0.242; P = 0.623). No difference was found in the distribution of genotype of IL-8-251A/T between the healthy control group and AP group neither in the frequency of A and T allele.

CONCLUSION

The MCP-1-2518 AA genotype of the population in Suzhou may be a protective genotype of AP, while one with higher frequency of G allele is more likely to suffer from pancreatitis. But the genotype of AA and the frequency of G allele could not predict the risk of severe AP. No correlation is found between the IL-8-251 polymorphism and the liability of AP.

Pathogen-dependent induction of cytokines and other soluble inflammatory mediators during intramammary infection of dairy cows

Mastitis is a highly prevalent and costly disease of dairy cows that is commonly caused by intramammary bacterial infection. The innate immune response to bacterial penetration of the mammary gland is evoked within hours of infection, and the rapidity and magnitude of this response have been demonstrated to influence the resolution of this disease. Cytokines and other mediators of inflammation are known to play critical roles in the innate immune response to intramammary infection. The objectives of this review are to summarize the current understanding of the cytokine response to intramammary infection, highlight recent findings identifying differences in the cytokine response to various bacterial pathogens, and discuss future research directions that will increase our knowledge of the role of inflammatory mediators in predicting and governing the outcome of mastitis.

Elevation of monocyte chemoattractant protein-1 in patients experiencing neurocognitive decline following carotid endarterectomy

BACKGROUND

Previous studies have demonstrated that elevated pre-operative monocyte count is an independent predictor of acute neurocognitive decline following carotid endarterectomy (CEA). Monocyte chemoattractant protein-1 (MCP-1), secreted by human endothelial and monocyte-like cells, is a potent mediator of inflammation and mononuclear cell trafficking. This study examines the relationship between peri-operative serum MCP-1 elevation and post-operative neurocognitive injury following CEA.

METHODS

Fifty-two patients undergoing CEA and 67 lumbar laminectomy (LL) controls were administered a battery of five neuropsychological tests pre-operatively and on post-operative day 1 (POD 1). Change in individual test scores from baseline to POD 1 were converted into Z-score and used to develop a point system quantifying the degree of neurocognitive dysfunction relative to change within the LL group. Neurocognitive injury following CEA was defined as a score greater than 2 standard deviations above mean total deficit scores of LL controls. Serum MCP-1 levels were measured pre-operatively and on POD 1 by enzyme-linked immunosorbent assay.

FINDINGS

Mean percent MCP-1 elevation was higher for the 13 injured CEA patients (147.7 +/- 32.4%) in our cohort compared to 39 age- and sex-matched uninjured CEA patients (76.0 +/- 16.5%). In unconditional multivariate logistic regression analysis, percent elevation in serum MCP-1 level was associated with neurocognitive injury one day after CEA (OR = 2.19, 95% CI = 1.13-4.26, P = 0.021, for a 100% elevation from pre-operative levels).

CONCLUSIONS

Peri-operative elevations in serum MCP-1 levels correlate with acute neurocognitive dysfunction following CEA. These data implicate an inflammatory mechanism in the pathogenesis of Ischaemic neurocognitive decline.

Association between IL-8 cytokine and cognitive performance in an elderly general population—The MEMO-Study

OBJECTIVES

To investigate the associations between circulating cytokines and specific neuropsychological domains of cognitive functioning (memory, processing speed and motor function) and general cognitive function (MMSE) in healthy elderly individuals.

METHODS

In a cross-sectional study of 369 community dwelling elderly subjects, we examined the relationship between serum IL-1beta, sIL-4R, IL-6, IL-8, IL-10, IL-12 and TNF-alpha concentrations and cognitive performance using an extensive standardized and validated cognitive test battery assessing memory, word fluency, perceptual/cognitive speed, attention and executive functioning, and motor speed.

RESULTS

Multivariate analysis adjusted for various confounders and Bonferroni correction for multiple comparisons demonstrated that increased serum concentrations of IL-8 were associated with poor performance in the memory and speed domains and in motor function. No significant associations were found between the remaining cytokines and domains of cognitive functioning. Global cognitive functioning, as measured with MMSE, was not associated with any cytokine.

CONCLUSIONS

This study suggests an association between circulating IL-8 concentrations and cognitive dysfunction in the elderly. An interaction between this cytokine and glial cells may help explain the pathophysiological mechanisms leading to cognitive impairment in our study group.

Vaginal IL-8 levels are positively associated with Candida albicans and inversely with lactobacilli in HIV-infected women

IL-8/CXCL8 is induced during infections, but has not been reported for Candida albicans colonization of the female genital tract. Cervicovaginal lavage (CVL) samples were collected from 406 HIV-infected women. IL-8 levels were evaluated by ELISA and compared with levels of C. albicans detected by potassium hydroxide (KOH) and PCR. Levels of lactobacilli, Gardnerella vaginalis and Mycoplasma hominis were also determined by PCR. IL-8 was significantly higher in samples from women with Candida, and regression analysis showed a positive association between IL-8 and Candida. In contrast, there was an inverse relationship between lactobacilli and IL-8. G. vaginalis and M. hominis were not significantly associated with IL-8. This study has shown an association between C. albicans and levels of IL-8 in mucosal genital fluid.

Reactive oxygen species and chemokines: Are they elevated in the esophageal mucosa of children with gastroesophageal reflux disease?

AIM: To determine the role of inflammatory cytokines and reactive oxygen species (ROS) in childhood reflux esophagitis.

METHODS: A total of 59 subjects who had complaints suggesting GERD underwent esophagogastroduodenoscopy. Endoscopic and histopathologic diagnosis of reflux esophagitis was established by Savary-Miller and Vandenplas grading systems, respectively. Esophageal biopsy specimens were taken from the esophagus 20% proximal above the esophagogastric junction for conventional histopathological examination and the measurements of ROS and cytokine levels. ROS were measured by chemiluminescence, whereas IL-8 and MCP-1 levels were determined with quantitative immunometric ELISA on esophageal tissue. Esophageal tissue ROS, IL-8 and MCP-1 levels were compared among groups with and without endoscopic/histo-pathologic esophagitis.

RESULTS: Of 59 patients 28 (47.5%) had normal esophagus whereas 31 (52.5%) had endoscopic esophagitis. In histopathological evaluation, almost 73% of the cases had mild and 6.8% had moderate degree of esophagitis. When ROS and chemokine levels were compared among groups with and without endoscopic esophagitis, statistical difference could not be found between patients with and without esophagitis. Although the levels of ROS, IL-8 and MCP-1 were found to be higher in the group with histopathological reflux esophagitis, this difference was not statistically significant.

CONCLUSION: These results suggest that the grade of esophagitis is usually mild or moderate during childhood and factors apart from ROS, IL-8 and MCP-1 may be involved in the pathogenesis of reflux esophagitis in children.

Effects of endothelial basement membrane on neutrophil adhesion and migration

The influence of the sub-endothelial basement membrane (BM) on the adhesion and migration of leukocytes is not well-defined. We therefore investigated the behaviour of human neutrophils on purified BM proteins and on BM deposited by short- or long-term cultures of endothelial cells (EC). The adhesion, but not migration velocities, of neutrophils activated with interleukin-8 was dependent on the coating concentrations of purified collagen, laminin or fibronectin. In contrast, adhesion was similar on matrices deposited by 3-day or 20-day cultures of EC, but neutrophils migrated more slowly on the distinct BM that formed over 20 days. In addition, while adhesion on all surfaces was greatly reduced when neutrophils were treated with antibody against beta(2)-integrins, antibody against beta(1)-integrins only inhibited adhesion to the 20-day BM. Thus, the native BM has distinct effects on integrin usage and migration by neutrophils, which are not reproduced by purified proteins or matrix deposited early during endothelial culture.

The cytosolic pattern recognition receptor NOD1 induces inflammatory interleukin-8 during Chlamydia trachomatis infection

Inflammation is a hallmark of chlamydial infections, but how inflammatory cytokines are induced is not well understood. Pattern recognition receptors (PRR) of the host innate immune system recognize pathogen molecules and activate intracellular signaling pathways that modulate immune responses. The role of PRR such as Toll-like receptors (TLR) and nucleotide-binding oligomerization domain (NOD) proteins in the endogenous interleukin-8 (IL-8) response induced during Chlamydia trachomatis infection is not known. We hypothesized that a PRR is essential for the IL-8 response induced by C. trachomatis infection. RNA interference was used to knock down the TLR signaling partner MyD88 as well as NOD1 and its signaling molecule receptor-interacting protein 2 (RIP2). IL-8 induced at 30 h postinfection by C. trachomatis was dependent on NOD1 signaling through RIP2; however, the IL-8 response was independent of MyD88-dependent TLR signaling. Activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cellular signaling pathway, which is essential for up-regulation of IL-8 in response to C. trachomatis infection, was independent of NOD1 or RIP2. We conclude that the endogenous IL-8 response induced by C. trachomatis infection is dependent upon NOD1 PRR signaling through RIP2 as part of a signal system requiring multiple inputs for optimal IL-8 induction. Since ERK is not activated through this pathway, a concomitant interaction between the host and bacteria is additionally required for full activation of the endogenous IL-8 response.

Caspase-4 interacts with TNF receptor-associated factor 6 and mediates lipopolysaccharide-induced NF-kappaB-dependent production of IL-8 and CC chemokine ligand 4 (macrophage-inflammatory protein-1 )

Human caspase-4 does not have a corresponding mouse ortholog. Caspase-4 falls within the class of "inflammatory caspases," being homologous with human caspases 1 and 5 and mouse caspases 1, 11, and 12. To address the function of caspase-4, we generated caspase-4-deficient human THP1 monocytic cell lines which exhibited substantially reduced LPS-induced secretion of several chemokines and cytokines, including IL-8 (CXCL8), CCL4 (macrophage-inflammatory protein-1beta), CCL20 (macrophage-inflammatory protein-3alpha), and IL-1beta. The LPS-induced expression of the mRNAs encoding these cytokines was correspondingly reduced in the caspase-4-deficient clones. Because a specific NF-kappaB inhibitor blocked LPS-induced IL-8 and CCL4 mRNA expression as well as IL-8 and CCL4 secretion in THP1 cells, we investigated the role of caspase-4 in NF-kappaB signaling. LPS-induced NF-kappaB nuclear translocation and activation were inhibited in all caspase-4-deficient clones. LPS stimulation led to the interaction of endogenous caspase-4 and TNFR-associated factor 6 (TRAF6) via a TRAF6-binding motif (PPESGE), which we identified in caspase-4. Mutation of this site in caspase-4 resulted in the loss of the TRAF6-caspase-4 interaction. Similar TRAF6-binding motifs are known to be functionally important for TRAF6 interactions with other molecules including caspase-8, and for mediating NF-kappaB activation in various immune and nonimmune cell types. Our data suggest that the TRAF6-caspase-4 interaction, triggered by LPS, leads to NF-kappaB-dependent transcriptional up-regulation and secretion of important cytokines and chemokines in innate immune signaling in human monocytic cells.

Necrotic foci, elevated chemokines and infiltrating neutrophils in the liver of glycogen storage disease type Ia

BACKGROUND/AIMS

Glycogen storage disease type Ia (GSD-Ia) patients manifest the long-term complication of hepatocellular adenoma (HCA) of unknown etiology. We showed previously that GSD-Ia mice exhibit neutrophilia and elevated serum cytokine levels. This study was conducted to evaluate whether human GSD-Ia patients exhibit analogous increases and whether in GSD-Ia mice a correlation exists between immune abnormalities and, biochemical and histological alterations in the liver.

METHODS

Differential leukocyte counts and cytokine levels were investigated in GSD-Ia patients. Hepatic chemokine production, neutrophil infiltration, and histological abnormalities were investigated in GSD-Ia mice.

RESULTS

We show that GSD-Ia patients exhibit increased peripheral neutrophil counts and serum interleukin-8 (IL-8). Compared to normal subjects, HCA-bearing GSD-Ia patients have a 2.8-fold higher serum IL-8 concentration, while GSD-Ia patients without HCA have a 1.4-fold higher concentration. Hepatic injury in GSD-Ia mice is evidenced by necrotic foci, markedly elevated infiltrating neutrophils, and increased hepatic production of chemokines.

CONCLUSIONS

Peripheral neutrophilia and elevated serum chemokines are characteristic of GSD-Ia with HCA-bearing GSD-Ia patients having the highest serum IL-8. In GSD-Ia mice these elevations correlate with elevated hepatic chemokine levels, neutrophil infiltration, and necrosis. Taken together, peripheral neutrophilia and increased serum chemokines may indicate hepatic injuries in GSD-Ia.

Cytokine Profiling in Abacavir Hypersensitivity Patients

Background

Abacavir hypersensitivity in genetically susceptible individuals implicates an abacavir-specific T-cell response to either the parent drug or a metabolite generated in vivo. We have analysed the cytokine profile in antigen-presenting cells and the T-lymphocytes that are involved in the pathological immune response to abacavir.

Methods

In this study, we compared abacavir-specific cytokine responses in cultured peripheral blood mononuclear cells (PBMCs) from HIV-infected abacavir hypersensitive, tolerant and naive individuals. Cells were cultured in the presence or absence of abacavir. Cytokine expression was determined by microarray analysis, enzyme-linked immunosorbent assays and flow cytometry.

Results

We demonstrated using in vitro models of immune activation that the production of interferon-γwas specifically induced by abacavir treatment in PBMCs obtained from hypersensitive patients carrying the HLA-B*5701 allele (median 123.86 compared with -30.83 for tolerant controls, P=0.001).

Conclusion

These results provide further insight into the immunological and metabolic basis of abacavir hypersensitivity syndrome. In vitro assays could assist in the identification of susceptible loci by providing a surrogate marker for the hypersensitivity reaction. Such a marker could be studied in unexposed individuals to shed further light on the immunopathogenesis of the abacavir hypersensitivity syndrome.

Associations of interleukin-6 with interleukin-1beta, interleukin-8 and macrophage inflammatory protein-1beta in midlife women

OBJECTIVE

The aim of the present study was to determine the associations of interleukin (IL)-6 with other cytokines and chemokines and to compare these associations in peri- and postmenopausal women.

METHODS

Ninety-nine perimenopausal and 92 postmenopausal women were enrolled in this study. Serum concentrations of IL-6, IL-1beta, IL-2, IL-4, IL-5, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor (TNF)-alpha, interferon gamma, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage (GM)-CSF, macrophage inflammatory protein (MIP)-1beta and monocyte chemotactic protein (MCP)-1 were measured simultaneously using a multiplexed cytokine assay.

RESULTS

Among the 17 cytokines, IL-6, IL-1beta, IL-5, IL-7, IL-8, IL-10, MCP-1 and MIP-1beta were detected in serum in more than 50% of the women. Serum levels of IL-4 and MCP-1 in postmenopausal women were significantly higher than those in perimenopausal women. Serum IL-6 concentrations showed significant and positive correlations with serum concentrations of IL-1beta, IL-8, MIP-1beta, IL-7 and MCP-1 in women regardless of menopausal status, and these correlations were still significant after adjustment for age and body mass index.

CONCLUSION

Serum IL-6 concentration was found to be closely associated with serum concentrations of IL-1beta, IL-8, MIP-1beta, IL-7 and MCP-1 in women regardless of menopausal status, suggesting that these cytokines act in concert with the progression of several symptoms and various diseases.

Inflammation and cancer: an ancient link with novel potentials

Infection and chronic inflammation contribute to about 1 in 4 of all cancer cases. Mediators of the inflammatory response, e.g., cytokines, free radicals, prostaglandins and growth factors, can induce genetic and epigenetic changes including point mutations in tumor suppressor genes, DNA methylation and post-translational modifications, causing alterations in critical pathways responsible for maintaining the normal cellular homeostasis and leading to the development and progression of cancer. Recent discovery of an interaction between microRNAs and innate immunity during inflammation has further strengthened the association between inflammation and cancer.

Apoptotic myocytes generate monocyte chemoattractant protein-1 and mediate macrophage recruitment

The mechanisms by which apoptotic myocytes are removed by macrophages have not been fully elucidated. This study examined whether apoptotic myocytes actively recruit macrophages by generating monocyte chemoattractant protein-1 (MCP-1) in experiments in vitro and in vivo. Neonatal rat cardiac myocytes were incubated for 4 h in the presence or absence of staurosporine (STS, 0.2-1 mumol/l), an apoptosis inducer. Nuclear staining with DAPI showed that STS induced apoptosis in a dose-dependent fashion. STS (1 mumol/l) caused extensive DNA fragmentation and increased caspase-3 activity compared with a serum-deprived control. MCP-1 mRNA and protein levels in myocytes increased twofold and fourfold, respectively, on STS treatment, and immunochemical staining revealed that apoptotic myocytes expressed MCP-1. To elucidate the role of MCP-1 expressed in apoptotic myocytes to recruit macrophages/monocytes, rat monocytes were incubated in the supernatant of STS-treated myocytes using a trans-well system. The culture medium of STS-treated myocytes recruited monocytes in a MCP-1-dependent fashion. In addition, experiments were performed in vivo using ischemia-reperfused rat hearts. Rats were subjected to 30 min of ligation of the left coronary artery followed by 24 h of reperfusion. After the reperfusion, in the ischemic border myocardium, 17.1 +/- 1.1% of myocytes were terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) positive. Moreover, double staining using the TUNEL technique and immunohistochemistry with MCP-1 antibody showed that 69.8 +/- 3.9% of TUNEL-positive myocytes expressed MCP-1 protein. Concomitantly, activated macrophages infiltrated the areas of apoptosis remarkably. These results suggest that apoptotic myocytes produce MCP-1, which have a critical role in the active recruitment of macrophages.

Mechanisms of Legionella pneumophila-induced interleukin-8 expression in human lung epithelial cells

BACKGROUND

Legionella pneumophila is a facultative intracellular bacterium, capable of replicating within the phagosomes of macrophages and monocytes, but little is known about its interaction with human lung epithelial cells. We investigated the effect of L. pneumophila on the expression of interleukin-8 (IL-8) in human A549 alveolar and NCI-H292 tracheal epithelial cell lines.

RESULTS

Infection of L. pneumophila strain, but not heat-killed strain, resulted in upregulation of IL-8. IL-8 mRNA expression was induced immediately after the infection and its signal became gradually stronger until 24 h after infection. On the other hand, IL-8 expression in A549 cells infected with L. pneumophila lacking a functional type IV secretion system was transient. The IL-8 expression was slightly induced at 16 h and increased at 24 h after infection with flagellin-deficient Legionella. Activation of the IL-8 promoter by L. pneumophila infection occurred through the action of nuclear factor-kappaB (NF-kappaB). Transfection of dominant negative mutants of NF-kappaB-inducing kinase, IkappaB kinase and IkappaB inhibited L. pneumophila-mediated activation of IL-8 promoter. Treatment with hsp90 inhibitor suppressed L. pneumophila-induced IL-8 mRNA due to deactivation of NF-kappaB.

CONCLUSION

Collectively, these results suggest that L. pneumophila induces activation of NF-kappaB through an intracellular signaling pathway that involves NF-kappaB-inducing kinase and IkappaB kinase, leading to IL-8 gene transcription, and that hsp90 acts as a crucial regulator in L. pneumophila-induced IL-8 expression, presumably contributing to immune response in L. pneumophila. The presence of flagellin and a type IV secretion system are critical for Legionella to induce IL-8 expression in lung epithelial cells.

Glycated human serum albumin induces interleukin 8 mRNA expression through reactive oxygen species and NADPH oxidase-dependent pathway in monocyte-derived U937 cells

Glycated human serum albumin (Glc-HSA) has previously been reported (Higai K., et al., 2006) to induce E-selectin expression on human umbilical vein endothelial cells through activation of NADPH oxidase; however, Glc-HSA signaling in monocytes remains obscure. To clarify the influence on human monocyte-derived U937 cells, U937 cells were stimulated with Glc-HSA and glycoaldehyde-dimer-modified HSA (GA-HSA) for 2 h in the absence and presence of the protein kinase C (PKC) inhibitor calphostin and the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) and NADPH oxidase inhibitor apocynin; interleukin-8 (IL-8) mRNA expression was determined by RT-PCR. As a result, IL-8 mRNA expression in U-937 cells was time- and dose-dependently enhanced by stimulation with Glc-HSA and GA-HSA. Furthermore, promoter activity of the IL-8 reporter gene was enhanced approximately 2-fold by stimulation with Glc-HSA and GA-HSA. Nuclear factor kappaB (NFkappaB) and activator protein-1 (AP-1) reporter genes were also enhanced although CCAAT/enhancer binding protein (C/EBP) was not affected. IL-8 mRNA expression was suppressed by NAC and apocynin but not calphostin in cells stimulated with Glc-HSA; however, its expression in cells stimulated with GA-HSA was suppressed by calphostin but not NAC. These results indicated that IL-8 mRNA expression was upregulated by NFkappaB and AP-1 in U937 cells stimulated with Glc-HSA and GA-HSA, but the signaling pathways were different.

Stromal fibroblasts in colorectal liver metastases originate from resident fibroblasts and generate an inflammatory microenvironment

Cancer-associated stromal fibroblasts (CAFs) are the main cellular constituents of reactive stroma in primary and metastatic cancer. We analyzed phenotypical characteristics of CAFs from human colorectal liver metastases (CLMs) and their role in inflammation and cancer progression. CAFs displayed a vimentin(+), alpha-smooth-muscle actin(+), and Thy-1(+) phenotype similar to resident portal-located liver fibroblasts (LFs). We demonstrated that CLMs are inflammatory sites showing stromal expression of interleukin-8 (IL-8), a chemokine related to invasion and angiogenesis. In vitro analyses revealed a striking induction of IL-8 expression in CAFs and LFs by tumor necrosis factor-alpha (TNF-alpha). The effect of TNF-alpha on CAFs is inhibited by the nuclear factor-kappaB inhibitor parthenolide. Conditioned medium of CAFs and LFs similarly stimulated the migration of DLD-1, Colo-678, HuH7 carcinoma cells, and human umbilical vein endothelial cells in vitro. Pretreatment of CAFs with TNF-alpha increased the chemotaxis of Colo-678 colon carcinoma cells by conditioned medium of CAFs; however, blockage of IL-8 activity showed no inhibitory effect. In conclusion, these data raise the possibility that the majority of CAFs in CLM originate from resident LFs. TNF-alpha-induced up-regulation of IL-8 via nuclear factor-kappaB in CAFs is an inflammatory pathway, potentially permissive for cancer invasion that may represent a novel therapeutic target.