Production of monocyte chemotactic and activating factor (MCAF) by human dermal fibroblasts in response to interleukin 1 or tumor necrosis factor

Microfluidic-driven mixing of high molecular weight polymeric complexes for precise nanoparticle downsizing

Chitosan (CHIT) and hyaluronic acid (HA) are two polysaccharides (PSs) with high value in several biomedical applications. In this study, we present a microfluidic method to synthetize CHIT-HA NPs to overcome the disadvantages of the dropwise approach generally used for nanoprecipitation of polyelectrolyte complexes. The proposed microfluidic approach enables to generate monodisperse suspensions of NPs with ≈100 nm of size compared to the dropwise method that generated ≈2 times bigger NPs. Finally, we evaluated the potential of obtained NPs in an inflammatory scenario. The treatment with NPs led to the reduction of the main inflammatory molecules produced by macrophages (PGE₂, IL-6, IL-8, MCAF and TNF-α) and fibroblasts (IL-1 α, PGE₂, TNF-α) stimulated with lipopolysaccharide or conditioned medium, respectively. This study demonstrates that our approach can be used to enhance the synthesis of nanocarriers based on bioactive macromolecules.

TNF-α in Uveitis: From Bench to Clinic

Uveitis is an inflammation of the iris, ciliary body, vitreous, retina, or choroid, which has been shown to be the first manifestation of numerous systemic diseases. Studies about the immunopathogenesis and treatment of uveitis are helpful to comprehend systemic autoimmune diseases, and delay the progression of systemic autoimmune diseases, respectively. Tumor necrosis factor-alpha (TNF-α), a pleiotropic cytokine, plays a pivotal role in intraocular inflammation based on experimental and clinical data. Evidence of the feasibility of using anti-TNF-α agents for uveitis management has increased. Although there are numerous studies on TNF-α in various autoimmune diseases, the pathological mechanism and research progress of TNF-α in uveitis have not been reviewed. Therefore, the objective of this review is to provide a background on the role of TNF-α in the immunopathogenesis of uveitis, as well as from bench to clinical research progress, to better guide TNF-α-based therapeutics for uveitis.

Downregulation of the S1P Transporter Spinster Homology Protein 2 (Spns2) Exerts an Anti-Fibrotic and Anti-Inflammatory Effect in Human Renal Proximal Tubular Epithelial Cells

Sphingosine kinase (SK) catalyses the formation of sphingosine 1-phosphate (S1P), which acts as a key regulator of inflammatory and fibrotic reactions, mainly via S1P receptor activation. Here, we show that in the human renal proximal tubular epithelial cell line HK2, the profibrotic mediator transforming growth factor β (TGFβ) induces SK-1 mRNA and protein expression, and in parallel, it also upregulates the expression of the fibrotic markers connective tissue growth factor (CTGF) and fibronectin. Stable downregulation of SK-1 by RNAi resulted in the increased expression of CTGF, suggesting a suppressive effect of SK-1-derived intracellular S1P in the fibrotic process, which is lost when SK-1 is downregulated. In a further approach, the S1P transporter Spns2, which is known to export S1P and thereby reduces intracellular S1P levels, was stably downregulated in HK2 cells by RNAi. This treatment decreased TGFβ-induced CTGF and fibronectin expression, and it abolished the strong induction of the monocyte chemotactic protein 1 (MCP-1) by the pro-inflammatory cytokines tumor necrosis factor (TNF)α and interleukin (IL)-1β. Moreover, it enhanced the expression of aquaporin 1, which is an important water channel that is expressed in the proximal tubules, and reverted aquaporin 1 downregulation induced by IL-1β/TNFα. On the other hand, overexpression of a Spns2-GFP construct increased S1P secretion and it resulted in enhanced TGFβ-induced CTGF expression. In summary, our data demonstrate that in human renal proximal tubular epithelial cells, SK-1 downregulation accelerates an inflammatory and fibrotic reaction, whereas Spns2 downregulation has an opposite effect. We conclude that Spns2 represents a promising new target for the treatment of tubulointerstitial inflammation and fibrosis.

The Hierarchy of Proinflammatory Cytokines in Ocular Inflammation

PURPOSE

The concept of tissue-dependent cytokine hierarchy has been demonstrated in a number of diseases, but it has not been investigated in ophthalmic diseases. Here, we evaluated the functional hierarchy of interleukin-1β (IL-1β), IL-6, IL-17A, and tumor necrosis factor (TNF) in the induction of ocular inflammation.

MATERIALS AND METHODS

We delivered adeno-associated virus (AAV) vectors expressing IL-1β, IL-6, IL-17A, or TNF intravitreally in naïve C57/BL6 mice and compared and contrasted the inflammatory effects in the eye 5 weeks after AAV-mediated gene transfer. We also used an in vitro human system to test the effect of cytokines on barrier function.

RESULTS

We found that IL-1β had the highest ability to initiate ocular inflammation. The continuous overexpression of IL-1β resulted in a significant upregulation of additional proinflammatory mediators in the eye. Using scanning laser ophthalmoscope and optical coherence tomography imaging techniques, we showed that a low dose of AAVIL-1β was sufficient and was as pathogenic as a high dose of TNF in inducing vascular leakage, retinal degeneration, and cellular infiltration. Furthermore, only a marginal increase in IL-1β was enough to cause cellular infiltration, thus confirming the highly pathogenic nature of IL-1β in the eye. Contrary to our expectation, IL-6 or IL-17A had minimal or no effect in the eye. To examine the clinical relevance of our findings, we used an impedance assay to show that IL-1β alone or TNF alone was able to cause primary human retinal endothelial cell barrier dysfunction in vitro. Again, IL-6 alone or IL-17A alone had no effect on barrier function; however, in the presence of IL-1β or TNF, IL-17A but not IL-6 may provide additive proinflammatory effects.

CONCLUSIONS

Our studies demonstrate the existence of a functional hierarchy of proinflammatory cytokines in the eye, and we show that IL-1β is the most pathogenic when it is continuously expressed in the eye.

Interleukin 8 correlates with intestinal involvement in surgically treated infants with necrotizing enterocolitis

PURPOSE

The aim of this study was to test the predictive value of interleukin (IL) 8 in the assessment of intestinal involvement in necrotizing enterocolitis (NEC).

METHODS

Forty infants with surgically treated NEC were classified into 3 groups based on intestinal involvement during laparotomy: focal (n = 11), multifocal (n = 16), and panintestinal (n = 13). Preoperatively obtained serum levels of IL-8, C-reactive protein, white blood cell count, and platelet count were correlated with intestinal involvement using logistic regression models.

RESULTS

Interleukin 8 correlated significantly with intestinal involvement in infants with surgically treated NEC (odds ratio, 1.74; confidence interval, 1.27-2.39; P < .001). An exploratory IL-8 cutoff value of 449 pg/mL provided a specificity of 81.8% and sensitivity of 82.8% to discriminate focal from multifocal and panintestinal disease. An IL-8 cutoff value of 1388 pg/mL provided a specificity of 77.8% and a sensitivity of 76.9% to discriminate panintestinal disease from focal and multifocal disease.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate a significant correlation of IL-8 with intestinal involvement in advanced NEC in a large patient population. Our results indicate that IL-8 may be a promising biomarker for assessing intestinal involvement in infants with advanced NEC.

Monocyte Chemoattractant Protein 1 (MCP-1) in obesity and diabetes

Monocyte Chemoattractant Protein-1 (MCP-1) is the first discovered and most extensively studied CC chemokine, and the amount of studies on its role in the etiologies of obesity- and diabetes-related diseases have increased exponentially during the past two decades. This review attempted to provide a panoramic perspective of the history, regulatory mechanisms, functions, and therapeutic strategies of this chemokine. The highlights of this review include the roles of MCP-1 in the development of obesity, diabetes, cardiovascular diseases, insulitis, diabetic nephropathy, and diabetic retinopathy. Therapies that specifically or non-specifically inhibit MCP-1 overproduction have been summarized.

Origin and function of tumor stroma fibroblasts

Tumor development is critically dependent on the formation of a supporting stroma consisting of neovasculature, inflammatory cells and activated fibroblasts. Activated fibroblasts present a heterogeneous cell population not only in regard to the expression of marker molecules but also to their origin and molecular signaling properties. The plasticity of this cell type is pointed out by the multiple transdifferentiation events that lead to the generation of activated fibroblasts which can arise from resting fibroblasts, epithelial and endothelial cells as well as from mesenchymal stem cells. Cellular in vitro and in vivo experiments have changed the perspective of fibroblasts from passive "bystanders" in the tumor microenvironment to that of important drivers of tumor progression. Here, we describe the multiple origins of fibroblast recruitment to the tumor tissue as well as the function of activated fibroblasts during tumor initiation, progression, metastasis and anti-VEGF resistance. The identification of markers present in activated fibroblasts as well as a better understanding how these cells influence other tumor compartments has led to the clinical development of anti-tumor therapies.

Resveratrol, a Polyphenolic Phytostilbene, Inhibits Endothelial Monocyte Chemotactic Protein-1 Synthesis and Secretion

BACKGROUND/AIMS

Resveratrol is a naturally occurring polyphenol phytoestrogen and one of several constituents of red wine thought to be cardioprotective. We investigated the effect of resveratrol on the expression of the atherogenic chemokine, monocyte chemotactic protein-1 (MCP-1).

METHODS

Human umbilical vein endothelial cells were stimulated with interleukin-1beta (IL-1beta) in the absence or presence of resveratrol. MCP-1 levels were determined by ELISA and MCP-1 mRNA was measured.

RESULTS

Resveratrol (1-100 microM) dose-dependently inhibited IL-1beta-stimulated MCP-1 secretion, with approximately 45% inhibition at 50 microM resveratrol. This was a Gi-protein- and NO-dependent effect. Resveratrol also significantly inhibited MCP-1 gene expression in a Gi-protein-dependent but NO-independent manner. While resveratrol had no effect on MCP-1 mRNA degradation, it inhibited MCP-1 promoter activity and reduced nuclear factor kappaB and activator protein-1 binding activity induced by IL-1beta. Moreover, while hemoxygenase-1 (HO-1) expression was induced by resveratrol in human umbilical vein endothelial cells, neither treatment with the HO-1 inhibitor tin-protoporphyrin IX nor siRNA-directed knockdown of HO-1 had any effect on the inhibition of MCP-1 mRNA or protein secretion by resveratrol.

CONCLUSION

These data demonstrate an inhibitory effect of resveratrol on MCP-1 synthesis and secretion, mediated via distinct signaling pathways. The inhibition of MCP-1 may represent a novel cardioprotective mechanism of resveratrol.

The role of chemokines in Schistosoma mansoni granuloma formation

The eradication of parasitic diseases, such as schistosomiasis, has been the focus of investigations worldwide for many decades. However, attempts to control their continual spread have, at best, been met with limited success. In the face of these results, it is important to attempt to understand and thus to control the pathology of these widespread diseases. In this review, Nicholas Lukacs, Steven Kunkel, Robert Strieter and Stephen Chensue focus on a family of cytokines that play a pertinent role for leukocyte recruitment in chronic inflammation.

Phenotypic change regulates monocyte chemoattractant protein-1 (MCP-1) gene expression in human retinal pigment epithelial cells

We investigated the expression profile of monocyte chemoattractant protein-1 (MCP-1) in human retinal pigment epithelial (RPE) cells under different culture conditions and evaluated the molecular mechanism responsible for MCP-1 gene expression in RPE cells. After cellular confluence, total RNA was extracted and used for RT-PCR. Medium conditioned by RPE was used for ELISA and Western blotting. The result showed that RPE cells cultured on plastic expressed MCP-1 constitutively in the absence of any stimuli. On the other hand, growing human RPE on laminin-coated flasks instead of plastic reduced the production of MCP-1. In the RPE cells cultured on plastic, IkappaB was degraded and A20 protein increased concomitantly. MCP-1 upregulation in RPE cells on plastic was attenuated by the addition of MG-132, a proteasome inhibitor. Also, the addition of pyrolidine dithiocarbonate (PDTC) and hypoxic conditions (0.5% O2) decreased MCP-1 production in these cells. These findings suggested that the expression profile of MCP-1 is regulated by phenotypic alterations of the RPE cells. And the increased MCP-1 expression in RPE cells cultured on plastic is caused via spontaneous activation of NFkappaB induced by susceptibility to oxidative stress.

High levels of interleukin-1 in patients with endemic pemphigus foliaceus

Endemic pemphigus foliaceus (EPF) is an autoimmune disease characterized by blister formation with a loss of cohesion and infiltration of inflammatory cells. We observed that supernatants of peripheral blood mononuclear cells from patients produced significantly more interleukin-1beta (IL-1beta) than those from stimulated healthy controls. Furthermore, a Th2 bias was observed in EPF patients when the IL-5/gamma interferon ratio was analyzed. These results indicate that cells from pemphigus patients react with a vigorous proinflammatory response.

Serine protease inhibitors modulate chemotactic cytokine production by human lung fibroblasts in vitro

Chemotactic chemokines can be released from lung fibroblasts in response to interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. An imbalance between proteases and antiproteases has been observed at inflammatory sites, and, therefore, protease inhibitors might modulate fibroblast release of chemotactic cytokines. To test this hypothesis, serine protease inhibitors (FK-706, alpha(1)-antitrypsin, or N(alpha)-p-tosyl-L-lysine chloromethyl ketone) were evaluated for their capacity to attenuate the release of neutrophil chemotactic activity (NCA) or monocyte chemotactic activity (MCA) from human fetal lung fibroblasts (HFL-1). Similarly, the release of the chemoattractants IL-8, granulocyte colony-stimulating factor, monocyte chemoattractant protein-1, macrophage colony-stimulating factor, and granulocyte/macrophage colony-stimulating factor, from HFL-1, were evaluated in response to IL-1beta and TNF-alpha. NCA, MCA, and chemotactic cytokines were attenuated by FK-706. However, matrix metalloproteinase inhibitors were without effect, and cysteine protease inhibitors only slightly attenuated chemotactic or cytokine release. These data suggest that IL-1beta and TNF-alpha may stimulate lung fibroblasts to release NCA and MCA by a protease-dependent mechanism and that serine protease inhibitors may attenuate the release.

Monocyte chemoattractant protein-1 expression correlates with macrophage infiltration and tumor vascularity in human esophageal squamous cell carcinomas

Tumor angiogenesis requires the production of angiogenic factors by tumor and stromal cells. Macrophages are key effectors of angiogenesis and reported to contribute to tumor angiogenesis in several carcinomas. To investigate interactions between tumor cells and macrophages in angiogenesis, we examined macrophage infiltration, tumor vascularity and expression of monocyte chemoattractant protein (MCP)-1, CC chemokine receptor 2 (CCR2) and vascular endothelial growth factor (VEGF) in 57 archival specimens from patients with esophageal dysplasia (n = 9) and squamous cell carcinomas (n = 48). Expression of MCP-1 mRNA was also examined by reverse transcriptase-polymerase chain reaction (RT-PCR) in 7 esophageal carcinoma cell lines and fresh biopsy specimens from 14 patients. The number of infiltrating macrophages correlated closely with expression of VEGF by tumor cells and with neovascularization. Of the 7 cell lines, 4 (TE-1, 3, 5 and 13) constitutively expressed MCP-1 mRNA. In 9 (64.3%) of the 14 patients, MCP-1 mRNA was expressed at high levels in tumor tissues as compared to normal mucosa. MCP-1 immunoreactivity increased with the depth of tumor invasion (Tis 0%, T1 26.3%, T2, T3 42.1%). Moreover, macrophage and vessel counts were significantly higher in MCP-1-positive tumors than in MCP-1-negative tumors. Normal and dysplastic esophageal squamous epithelium showed no staining or faint cytoplasmic staining of MCP-1. Expression of CCR2 immunoreactivity was detected in the cytoplasm of mononuclear cells but not of vascular endothelial cells. These results suggest that interactions between cancer cells and macrophages are important for tumor angiogenesis. MCP-1 may play a role in progression of human esophageal carcinoma through its role in angiogenesis.

Significant correlation of monocyte chemoattractant protein-1 expression with neovascularization and progression of breast carcinoma

BACKGROUND

Macrophages often infiltrate into solid tumor tissues. Tumor-associated macrophages (TAMs) are known to play a crucial role in tumor progression. Monocyte chemoattractant protein-1 (MCP-1) is one of the major chemokines capable of inducing chemotactic migration of monocytes.

METHODS

With the objective of investigating the clinical significance of MCP-1, the authors analyzed the expression of MCP-1 and of some other molecules by immunohistochemistry in 230 samples of primary breast carcinoma tissue. MCP-1 staining was performed using an anti-MCP-1 monoclonal antibody, and it was assessed by grading the percentage of stained cells.

RESULTS

It was found that 117 breast tumor specimens (51%) had intensive staining in tumor cells. The expression of MCP-1 in tumor cells had a significant correlation with the expression of thymidine phosphorylase and membrane type 1-matrix metalloproteinase. In addition, MCP-1 expression tended to be associated with the accumulation of TAMs, which were counted by CD68 staining, and with microvessel density. MCP-1 expression in TAMs was correlated significantly with the histologic vessel invasion of tumor cells.

CONCLUSIONS

The results of this study suggest that MCP-1 may play key roles in macrophage recruitment, in the expression of angiogenic factors, and in the activation of matrix metalloproteinases in patients with breast carcinoma.

Cyclophosphamide stimulates lung fibroblasts to release neutrophil and monocyte chemoattractants

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

Cytokine release and cytotoxicity in human keratinocytes and fibroblasts induced by phenols and sodium dodecyl sulfate

Phenolic compounds used in pharmaceutical and industrial products can cause irritant contact dermatitis. We studied the effects of resorcinol, phenol, 3,5-xylenol, chloroxylenol, and 4-hexyl-resorcinol on normal human epidermal keratinocytes and dermal fibroblasts for cytotoxicity and cytokine release, determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide methodology and enzyme-linked immunosorbent assay, respectively. An inverse correlation between phenol concentrations causing a 50% reduction in keratinocyte and fibroblast viability at 24 h and their octanol water-partition coefficients (i.e., hydrophobicity) was observed. 3,5-xylenol, chloroxylenol, hexyl-resorcinol, and sodium dodecyl sulfate, but not resorcinol or phenol, induced release of interleukin-1alpha from keratinocytes at cytotoxic concentrations. Variable release of tumor necrosis factor-alpha and interleukin-8 from keratinocytes occurred only at toxic threshold concentrations of the phenols or sodium dodecyl sulfate. Subtoxic concentrations of phenols or sodium dodecyl sulfate did not induce cytokine release from keratinocytes. Neither the phenols nor sodium dodecyl sulfate induced release of the chemokines interleukin-8, growth-related oncogene-alpha or monocyte chemotactic protein-1 from fibroblasts. Conditioned media from keratinocytes treated with cytotoxic concentrations of 3,5-xylenol, chloroxylenol, hexyl-resorcinol, or sodium dodecyl sulfate stimulated further release of the chemokines from fibroblasts above that obtained with control media. Rabbit anti-interleukin-1alpha serum inhibited keratinocyte-conditioned media induction of chemokine release. We have shown a structure-cytotoxicity relationship for a series of phenols as well as an association of interleukin-1alpha release with a cytotoxic effect. We demonstrated a cytokine cascade amplification step by the actions of stimulated keratinocyte media on cultured dermal fibroblasts, identifying interleukin-1alpha as the principal initiator of chemokine synthesis.

Toxoplasma gondii induces the secretion of monocyte chemotactic protein-1 in human fibroblasts, in vitro

Secretion of Monocyte Chemotactic Protein-1 (MCP-1) by fibroblasts infected with Toxoplasma gondii was studied in vitro. A significantly higher MCP-1 secretion was observed 24 h after infection by live tachyzoites. Analysis of chemokine mRNA transcripts by RNase protection assay revealed that this MCP-1 secretion seems associated with increased MCP-1 mRNA expression. However, these increased levels of MCP-1 secretion and expression were not obtained after stimulation by heat-killed tachyzoites or parasites pre-treated by a specific inhibitor of phosphatidylcholine-specific phospholipase C (D609). Inhibition of parasite multiplication by pyrimethamine did not modify MCP-1 secretion. Thus, it appeared that the active penetration of T. gondii in cells was of major importance in the induction of MCP-1 secretion. None of the other chemokines studied by RNase protection assay (lymphotactin, RANTES, IP-10, MIP-1alpha, MIP-1beta, IL-8, and I-309) were expressed after infection by live tachyzoites. We also found that MCP-1 secretion induced by live T. gondii is blocked by inhibitors of nuclear factor (NF)-kappaB activation, ALLN and MG132. Such data indicate that NF-kappaB could be involved in T. gondii-induced MCP-1 production. MCP-1 secretion may contribute to the recruitment of monocytes and lymphocytes and thus participate in the control of T. gondii infection and in its pathogenesis.

Bradykinin stimulates lung fibroblasts to release neutrophil and monocyte chemotactic activity

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

Enhanced interleukin-8 production in THP-1 human monocytic cells by lipopolysaccharide from oral microorganisms and granulocyte-macrophage colony-stimulating factor

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been used to assist in bone marrow recovery during cancer chemotherapy. Interleukin-8 (IL-8) plays an important role in macrophage mediated inflammatory processes including exacerbation of periodontal diseases, one of the most common complications in GM-CSF receiving cancer patients. The effect of GM-CSF supplementation on IL-8 production was investigated in a human monocyte cell line THP-1, stimulated with lipopolysaccharide extracted from two oral microorganisms, Porphyromonas gingivalis and Fusobacterium nucleatum. Resting THP-1 cells were treated with lipopolysaccharide (1 microgram/ml) of P. gingivalis or F. nucleatum and/or GM-CSF (50 IU/ml) for varying time periods. The production of IL-8 in THP-1 cells was measured by a solid-phase enzyme-linked immunosorbent assay (ELISA). A very low level of the cytokine IL-8 was produced constitutive in THP-1 cells. Starting from 8 h of treatment and afterwards GM-CSF alone significantly increased IL-8 production in THP-1 cells. Lipopolysaccharide (1 microgram/ml) extracts from either F. nucleatum or P. gingivalis amplified IL-8 production 500-800 times in comparison to resting THP-1 cells. When lipopolysaccharide of F. nucleatum or P. gingivalis was supplemented with 50 IU/ml of GM-CSF, there was a statistically significant enhanced production of IL-8 by THP-1 cells after 1 day to 7 days of treatment as compared with lipopolysaccharide treatment alone. GM-CSF (50 IU/ml) also significantly increased IL-8 production from 2-7 days of treatment of THP-1 cells when supplemented with a positive control, phorbol-12-myristate-13 acetate (PMA), as compared to PMA treatment alone. These investigations using the in vitro THP-1 human monocyte cell model indicate that there may be an increase in the response on a cellular level to oral endotoxin following GM-CSF therapy as evidenced by enhanced production of the tissue-reactive inflammatory cytokine, IL-8.

Bleomycin Stimulates Lung Fibroblasts to Release Neutrophil and Monocyte Chemotactic Activity

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

The MCP/eotaxin subfamily of CC chemokines

Migration of leukocytes from the bone marrow to the circulation, the primary lymphoid organs and inflammatory sites is directed by chemokines and specific receptor interactions. Besides the role of this group of low molecular weight cytokines in leukocyte attraction and activation, anti-HIV and hematopoietic activities were also attributed to chemokines. On the basis of the number and arrangement of the conserved cysteines, chemokines are subdivided in two multi-member families, namely the CXC and CC chemokines, whereas fractalkine (CX3C) and lymphotactin (C) are unique relatives. The CC chemokines possess four cysteines of which the first two are adjacent. Functionally, they form a rather heterogeneous family. Here, the focus is on the monocyte chemotactic proteins and eotaxin which, on a structural basis, can be considered as a CC chemokine subfamily. Not only the protein sequences, but also the gene structures, chromosomal location, biological activities and receptor usage exhibit considerable similarities. The review is complemented with a comparison of the biological functions of the MCP/eotaxin-subfamily in physiology and pathology.

Expression of monocyte chemoattractant protein-1 in the bovine corpus luteum around the time of natural luteolysis

Monocyte chemoattractant protein (MCP-1) is a specific chemoattractant for monocytes/macrophages that could have a role in the influx of macrophages into the corpus luteum (CL) during structural luteolysis. In this study, reverse transcription-polymerase chain reaction and in situ hybridization were used to investigate MCP-1 mRNA expression in CL collected from 18 heifers between Days 15 and 20 of the estrous cycle. There was expression of mRNA encoding MCP-1 in luteal tissue from all cows; however, expression was greater in animals that had undergone luteolysis at the time of CL collection as compared to animals in which the CL was still functional. Similarly, in situ hybridization showed greater expression of mRNA encoding MCP-1 in CL after functional luteolysis. There was also evidence of increased MCP-1 mRNA expression in an animal with a functional CL where the systemic concentration of prostaglandin F2alpha metabolite was high at the time of tissue collection. T lymphocyte populations, identified by immunohistochemistry, had a distribution similar to that of cells expressing MCP-1 mRNA within the CL, but other cell types were also involved. These results demonstrate an increase in MCP-1 mRNA after functional luteolysis in the cow, which may be related to the influx of macrophages that occurs at this time.

Human lung fibroblasts release chemokinetic activity for monocytes constitutively

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

Expression of monocyte chemotactic protein-1 in human invasive ductal breast cancer

Monocyte chemotactic protein-1 (MCP-1) is a chemokine involved in the macrophage infiltration of tumor tissue. Tumor associated macrophages (TAMs) are a population of mononuclear-phagocytic cells, which can express complex functions related to tumor biology. The present study was designed to analyse the expression of MCP-1 in parenchymal and stromal elements on frozen sections of 27 breast invasive ductal carcinomas not otherwise specified (NOS) by immunohistochemistry. The expression of MCP-1 in tumor parenchyma and the degree of tumor differentiation were assessed. MCP-1 was detected in the parenchyma in 15 of 27 ductal carcinomas. Positive immunoreactivity manifested as diffuse, homogeneous, moderate or strong, cytoplasmic staining, confined to tumor epithelium. Generally, MCP-1-negative tumors tended to be well differentiated, while chemokine-positive tumors exhibited a low level of differentiation. MCP-1 immunoreactivity was also present in TAMs (CD68 positive cells) in 23 of 27 tumors, and in endothelial cells in 11 of 27 tumors. These results indicate that parenchymal and, more variably, stromal elements of human invasive ductal carcinomas NOS can express MCP-1 in vivo. Additionally, these findings suggest that MCP-1 expression in tumor parenchyma is correlated with the histological grade of ductal invasive breast carcinoma.

Alterations in the expression of chemokine mRNA levels in fibrosis-resistant and -sensitive mice after thoracic irradiation

Fibrosis, characterized by the accumulation of collagen, is a consequence of a chronic inflammatory response. The purpose of this study was to determine if the mRNA expression of the chemokines, lymphotactin (Ltn), RANTES, eotaxin, macrophage inflammatory protein (MIP)-1 alpha, -1 beta, and -2, interferon-inducible protein 10 (IP-10), and monocyte chemotactic protein-1 (MCP-1), are altered during the development of radiation-induced pneumonitis and fibrosis. Further, we wished to determine if these changes differ between two strains of mice that vary in their sensitivity to radiation fibrosis. Fibrosis-sensitive (C57BL/6) and fibrosis-resistant (C3H/HeJ) mice were irradiated with a single dose of 12.5 Gy to the thorax. Total lung RNA was prepared and hybridized utilizing RNase protection assays. Data were quantified by phosphorimaging and results normalized to a constituitively expressed mRNA L32. 8 weeks post-irradiation most chemokines measured were elevated to varying degrees. The degree of elevation of each chemokine was identical in both strains. This suggested that chemotactic activity for neutrophils, macrophages, and lymphocytes were occurring during pneumonitis. By 26 weeks post-irradiation, messages encoding Ltn, RANTES, IP-10, and MCP-1 were elevated only in fibrosis sensitive (C57BL/6) mice. In situ hybridization demonstrated that MCP-1 and RANTES transcripts were produced predominantly from macrophages and lymphocytes. These studies suggest that lymphocytic recruitment and activation are key components of radiation-induced fibrosis.

T-cell-independent granuloma formation in response to Mycobacterium avium: role of tumour necrosis factor-alpha and interferon-gamma

We used Mycobacterium avium infection in severe combined immunodeficiency (SCID) mice to examine T-cell-independent mechanisms of inflammatory cell recruitment. SCID mice infected with a virulent strain of M. avium (TMC724) were able to recruit macrophages to sites of mycobacterial replication and formed organized and coherent granulomas in the absence of functional T cells. Phagocyte recruitment was almost totally ablated by neutralization of either tumour necrosis factor-alpha (TNF-alpha) or interferon-gamma (IFN-gamma) in vivo demonstrating that granuloma formation was dependent on the presence of these cytokines. This was concomitant with a reduction in the in situ cytokine mRNA levels otherwise induced in infected mice, for chemokines, pro-inflammatory and regulatory cytokines, including TNF-alpha, IFN-gamma, macrophage inflammatory protein-1 alpha, interleukin-1 beta (IL-1 beta) and IL-10. Furthermore, in vivo treatment of infected mice with anti-asialo GM-1 antisera, which depletes natural killer (NK) cells, prevented recruitment of inflammatory cells. In vitro studies confirmed that M. avium was able to elicit IFN-gamma from SCID spleen in a dose-dependent manner. These data show for the first time that secretion of IFN-gamma from NK cells can mediate a T-cell-independent pathway of granuloma formation and cellular infiltration in response to mycobacteria.

Integrin-mediated stimulation of monocyte chemotactic protein-1 expression

We investigated whether activation of integrin receptors could modulate the expression of monocyte chemotactic protein-1 (MCP-1) in human hepatic stellate cells (HSC), mesenchymal cells responsible for extracellular matrix synthesis within the liver. When compared to non-adherent cells, HSC plated on collagen types I or IV, or fibronectin, showed increased MCP-1 gene expression and protein secretion in the conditioned medium. Increased MCP-1 secretion was also observed when cells were plated on dishes coated with a monoclonal antibody directed against the beta1-integrin subunit, demonstrating that ligation of beta1-integrins is sufficient to stimulate MCP-1 expression. Conversely, integrin-independent cell adhesion on poly-L-lysine did not modify MCP-1 secretion. Disruption of the actin cytoskeleton by cytochalasin D blocked the collagen-dependent increase in MCP-1 secretion. Chemotactic assay of HSC-conditioned medium showed that HSC plated on collagen secrete higher amounts of chemotactic factors for lymphomonocytes, and that MCP-1 accounts for the great majority of this effect. These findings indicate a novel mechanism of MCP-1 regulation possibly relevant in those conditions where HSC interact with an altered extracellular matrix.

Differential and time-dependent expression of monocyte chemoattractant protein-1 mRNA by astrocytes and macrophages in rat brain: effects of ischemia and peripheral lipopolysaccharide administration

Increasing evidence indicates a key role of chemoattractant cytokines in the accumulation of leukocytes in the central nervous system (CNS) during the course of inflammatory processes. Monocyte chemoattractant protein (MCP-1/JE), a member of the beta-chemokine (C-C chemokine) family, functions as a potent chemoattractant and activator for monocytes. We have investigated the induction of MCP-1 mRNA using in situ hybridization histochemistry (ISH) and characterized its cellular source by combination of ISH and immunocytochemistry in ischemic rat brains as well as in brains of endotoxin-treated rats. Our results show that 6 h-2 d after middle cerebral artery occlusion (MCAO), MCP-1 mRNA is present in astrocytes surrounding the ischemic tissue (penumbra). At later time points (after 4 d), MCP-1 mRNA is found in macrophages and reactive microglia in the infarcted tissue. Peripheral administration of the bacterial lipopolysaccharide (LPS) induced MCP-1 mRNA throughout the brain in a time-dependent manner (1 h-1 d, peak of expression 6-8 h) and was found in astrocytes. In summary, we have found expression of MCP-1 in (a) astrocytes and to a lesser extent in macrophages/reactive microglia after MCA-occlusion and in (b) astrocytes after peripheral administration of LPS. These findings support that MCP-1 is involved in the CNS response to acute trauma or infection and thus may play a key role in inflammatory processes of the brain.

Significant reduction of human monocyte chemotactic response to monocyte-chemotactic protein 1 in patients with primary and metastatic malignant melanoma

The recruitment of leukocytes from the peripheral blood is a key event for the development and composition of the inflammatory infiltrate in solid tumors and tumor metastases like malignant melanoma. Tumor-infiltrating lymphocytes (TIL) and tumor-associated macrophages (TAM) are thought to play a crucial rôle in tumor immunosurveillance. In malignant melanoma expression and secretion of monocyte-chemotactic protein 1 (MCP-1) have been demonstrated. MCP-1 serves as an attractant for monocytes and activated T-cells. In this study we addressed the question whether circulating monocytes show altered chemotaxis to MCP-1. Therefore the chemotactic responsiveness of monocytes towards MCP-1 was investigated in patients with primary and metastatic melanoma and compared to patients with basal cell carcinoma and healthy persons. The results show that monocytes from melanoma patients showed a significantly decreased chemotactic migration towards MCP-1 while chemotaxis to the stimulus N-formyl-methionyl-leucyl-phenylalanine (FMLP) remained normal. Patients with basal cell carcinoma showed normal monocyte chemotaxis to all stimuli tested. In primary melanoma, there was no relation of the number of TAM or TIL to the decreased chemotaxis of circulating monocytes to MCP-1. From these data it can be concluded that circulating monocytes from patients with primary and metastatic melanoma show a MCP-1-specific decrease in chemotactic migration. This may be due to deactivation or modulation of the MCP-1-receptor expression on these cells.

Chemokines: a superfamily of chemotactic cytokines

Chemokines are a bipartite family of chemotactic proteins that bear the structural hallmark of four cysteine residues, the first two of which are in tandem. The spectrum of action of chemokines encompasses a large number of leukocyte populations, including monocytes, granulocytes, lymphocytes, NK and dendritic cells. Although the spectrum of action of chemokines largely overlaps, clear differences are still present. Chemokines play an important role in the recruitment of leukocytes at the site of inflammation, allergic reaction and tumors. Available information on receptor usage by MCP-1 and related chemokines and signal transduction pathways is reviewed. The better understanding of signaling mechanisms will provide a new basis for the development of therapeutic strategies.

Immunotherapy for sepsis

In recent years, an improved understanding of the pathogenesis of sepsis, along with an explosion in the biotechnology industry, has led to the development of a variety of agents with potential to interdict the pathogenesis of sepsis at many points. This article reviews the rationale, efficacy and shortcomings of these immunotherapeutic agents as they relate to the management of human septic shock.

Induction of macrophage antiprotozoal activity by monocyte chemotactic and activating factor

To determine if monocyte chemotactic and activating factor (MCAF) induces intracellular antimicrobial activity, human monocyte-derived macrophages were treated with MCAF and challenged with Toxoplasma gondii and Leishmania donovani. Pretreatment with MCAF induced macrophages to inhibit protozoal replication by approximately 50%. These findings suggest a potential host defense role for MCAF in the inflammatory response to intracellular pathogens.

ST2/T1 protein functionally binds to two secreted proteins from Balb/c 3T3 and human umbilical vein endothelial cells but does not bind interleukin 1

The ST2/T1 receptor, a homologue of the interleukin 1 receptor (IL-1R), was expressed in COS and Drosophila S2 cells as a human IgG-Fc fusion protein. While a type I IL-1RFc fusion protein bound human IL-1 in vitro, the ST2Fc fusion protein did not. Furthermore, IL-1 stimulated a synthetic interleukin-8 promoter reporter gene that was cotransfected into Jurkat cells with a full-length IL-1R type I (IL-1RI) or a chimeric receptor composed of the IL-1RI extracellular domain and ST2 intracellular domain. In contrast, IL-1 did not stimulate the interleukin-8 promoter when cotransfected with a full-length ST2 or an ST2 extracellular/IL-1R intracellular domain fusion protein. Both IL-1RI and the IL-1R/ST2R chimeric receptor also activated a receptor-associated kinase and CSBP/p38 MAP kinase. Using ST2Fc receptor, we have identified, through receptor precipitation, receptor-dot blot and surface plasmon resonance, a putative ligand of ST2 secreted from Balb/c 3T3 and human umbilical vein endothelial cells. The putative ligand was also able to stimulate CSBP/p38 MAP kinase through the ST2 receptor. These results suggest that the ST2 is not an IL-1 receptor but rather has its own cognate ligand.

Chemokine response in mice infected with Mycobacterium tuberculosis

We show here that infection of murine macrophages with various strains of Mycobacterium tuberculosis induces the rapid in vitro expression of genes encoding chemokines macrophage inflammatory protein 1 alpha and macrophage inflammatory protein 2, which recruit neutrophils to sites of infection, and macrophage-recruiting chemokines 10-kDa, interferon-inducible protein (IP-10) and macrophage chemotactic protein 1. Three strains of M. tuberculosis, Erdman and the clinical isolates CSU 22 and CSU 46, induced similar levels of secretion of macrophage chemotactic protein 1 from infected macrophage monolayers; however, the Erdman strain failed to induce levels of secretion of tumor necrosis factor alpha similar to those induced by either CSU 22 or CSU 46. Using a low-dose aerosol infection model, we also found that while the Erdman strain induced negligible increases in chemokine mRNA levels in the lungs, infection with either CSU 22 or CSU 46 resulted in greater levels of mRNA production for all four chemokines tested. The growth of these strains in the lungs was, however, equally well contained by acquired host immunity. These data allow us to hypothesize that the chemokine response in the lungs probably does not control the protective granulomatous response and that perhaps other T-cell- or macrophage-associated cytokines such as tumor necrosis factor alpha or interleukin 12 may be involved in this process.

The detection and localization of monocyte chemoattractant protein-1 (MCP-1) in human ovarian cancer

Chemokines may control the macrophage infiltrate found in many solid tumors. In human ovarian cancer, in situ hybridization detected mRNA for the macrophage chemokine monocyte chemoattractant protein-1 (MCP-1) in 16/17 serous carcinomas, 4/4 mucinous carcinomas, 2/2 endometrioid carcinomas, and 1/3 borderline tumors. In serous tumors, mRNA expression mainly localized to the epithelial areas, as did immunoreactive MCP-1 protein. In the other tumors, both stromal and epithelial expression were seen. All tumors contained variable numbers of cells positive for the macrophage marker CD68. MCP-1 mRNA was also detected in the stroma of 5/5 normal ovaries. RT-PCR demonstrated mRNA for MCP-1 in 7/7 serous carcinomas and 6/6 ovarian cancer cell lines. MCP-1 protein was detected by ELISA in ascites from patients with ovarian cancer (mean 4.28 ng/ml) and was produced primarily by the cancer cells. Human MCP-1 protein was also detected in culture supernatants from cell lines and in ascites from human ovarian tumor xenografts which induce a peritoneal monocytosis in nude mice. We conclude that the macrophage chemoattractant MCP-1 is produced by epithelial ovarian cancer and that the tumor cells themselves are probably a major source. MCP-1 may contribute to the accumulation of tumor-associated macrophages, which may subsequently influence tumor behavior.

Regulation of monocyte chemotactic protein-1 gene expression in human endometrial cells in cultures

Bone marrow-derived leukocytes are present in human endometrium/decidua and are believed to serve a variety of functions in this tissue. The number and type of leukocytes in endometrium/decidua vary with the hormonal milieu of the ovarian cycle, with blastocyst implantation, and during pregnancy. The factors that regulate the recruitment of specific leukocytes to the endometrium and those that modulate the function or replication of leukocytes in this tissue are not well defined. In this study, we evaluated the potential for synthesis of monocyte chemotactic protein-1 (MCP-1), a polypeptide with monocyte/macrophage chemotactic and activating properties, in human endometrium and in separated endometrial stromal and epithelial cells. MCP-1 mRNA was readily detected by northern analysis of total RNA isolated from human endometrial tissue (n = 39 tissues from ovulatory women; n = 3 atrophic endometria from anovulatory women; n = 6 from women ingesting oral contraceptives or medroxyprogesterone acetate) and decidua parietalis at midtrimester (n = 6 pregnancies) and at term (n = 6 pregnancies). The levels of MCP-1 mRNA varied considerably among tissues; but in this relatively small number of samples, there was no apparent relationship between day of cycle, endocrine status, or duration of pregnancy and the level of MCP-1 mRNA. MCP-1 mRNA was detected in separated endometrial stromal cells and epithelial cells in culture. In confluent human endometrial stromal cells in the absence or presence of fetal bovine serum (10%, v/v), MCP-1 mRNA was detected by northern analysis of total RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of T cells and cytokines in effecting fibrosis

A number of humoral and cellular immune abnormalities are present in patients with early scleroderma (systemic sclerosis). Most of these abnormalities reflect ongoing autoimmune reactions of the cellular and humoral types, resulting in a variety of autoantibodies to cellular and tissue constituents. Evidence exists for a defect(s) in immunoregulation favoring excessive helper T cell activity. The presence of circulating cytokines and shed interleukin-2 receptors suggest ongoing cellular immune reactions are occurring, generating cytokines and lymphokines that are capable of effecting the vascular and fibrotic lesions that are hallmarks of the disease. Future directions for research are suggested that would focus on determining if, and at what point, fibroblasts might function autonomously to generate excessive matrix components and on determining the nature of the original antigenic stimulus that starts the scleroderma process.

Monocyte-chemoattractant protein 1 gene expression in intestinal epithelial cells and inflammatory bowel disease mucosa

BACKGROUND

Monocyte-chemoattractant protein 1 (MCP-1) activates macrophages and increases the migration of monocytes into tissue during inflammation. It was hypothesized that MCP-1 expression is involved in intestinal inflammation.

METHODS

MCP-1 protein was detected by immunohistochemistry and immunoprecipitation. Biological activity of MCP-1 was assessed using a chemotactic assay. MCP-1 messenger RNA (mRNA) levels were measured by quantitative reverse-transcription polymerase chain reaction.

RESULTS

In normal mucosa, MCP-1 was predominantly present in surface epithelium. In contrast, inflamed mucosa from patients with ulcerative colitis or Crohn's disease contained multiple cells immunoreactive for MCP-1, including spindle cells, mononuclear cells, and endothelial cells. Furthermore, MCP-1 mRNA expression was markedly increased in inflamed intestinal biopsy specimens from patients with inflammatory bowel disease. MCP-1 was detected in isolated intestinal epithelial cells and in conditioned media from Caco-2 cells. Caco-2 cell-conditioned media stimulated monocyte chemotaxis activity that was inhibited by anti-MCP-1 antibodies. Constituitive MCP-1 mRNA levels in Caco-2 cells were up-regulated by interleukin 1 beta and down-regulated by dexamethasone.

CONCLUSIONS

In addition to lamina propria macrophages, endothelial cells, and spindle cells, intestinal epithelial cells are able to produce MCP-1. MCP-1 is expressed constitutively in the intestinal colonic mucosa and is up-regulated during inflammation.

Leukocyte recruitment by monocyte chemotactic proteins (MCPs) secreted by human phagocytes

Phagocyte recruitment is an important immunological phenomenon in inflammation and cancer. A large family of selective chemotactic cytokines, designated chemokines, has recently emerged. Interleukin-8 (IL-8) is the prototype of such neutrophil activating factors, whereas MCP-1 is a well studied monocyte chemotactic protein. In vitro chemotactic assays were used to isolate and identify natural chemokines from mononuclear phagocytes and tumor cells. Additional new chemotactic proteins (MCP-2, MCP-3) attracting monocytes were also discovered by these methods. All chemokines are structurally related and show affinity for heparin. MCP-1, -2 and -3 have a comparable specific activity in monocyte chemotaxis assays. Specific and sensitive radioimmunoassays for MCP-1 and IL-8 were developed to study the regulation of their secretion by leukocytes. Monocytes or monocyte tumor cells produce MCP-1 and/or IL-8 in response to cytokines, virus, double stranded RNA, bacterial endotoxin, mitogen or phorbol ester. Granulocytes were found to secrete only minor amounts of MCP-1 and IL-8.

Localized expression of mRNA for phagocyte-specific chemotactic cytokines in human periodontal infections

In bacterial infections, mononuclear and polymorphonuclear phagocytes are key components of host defenses. Recent investigations have indicated that chemokines are able to recruit and activate phagocytes. In particular, interleukin-8 (IL-8) attracts polymorphonuclear leukocytes (PMNs), while monocyte chemoattractant protein-1 (MCP-1) is selective for cells of the monocyte/macrophage lineage. In this investigation, we analyzed the in situ expression of IL-8 and MCP-1 mRNAs in human periodontal infections. Specific mRNA was detected by in situ hybridization using 35S-labeled riboprobes in frozen tissue sections. Phagocytes (PMNs and macrophages) were specifically detected as elastase-positive or CD68+ cells by a three-stage immunoperoxidase technique. Results indicated that expression of phagocyte-specific cytokines was confined to selected tissue locations and, in general, paralleled phagocyte infiltration. In particular, IL-8 expression was maximal in the junctional epithelium adjacent to the infecting microorganisms; PMN infiltration was more prominent in the same area. MCP-1 was expressed in the chronic inflammatory infiltrate and along the basal layer of the oral epithelium. Cells of the monocyte/macrophage lineage were demonstrated to be present in the same areas. The observed expression pattern may be the most economic way to establish a cell-type-selective chemotactic gradient within the tissue that is able to effectively direct polymorphonuclear phagocyte migration toward the infecting microorganisms and modulate mononuclear phagocyte infiltration in the surrounding tissues. This process may optimize host defenses and contribute to containing leukocyte infiltration to the infected and inflamed area, thus limiting tissue damage.

Cytokine production by keratinocytes and mononuclear infiltrates in oral lichen planus

Cytokine generation by tissue-infiltrating mononuclear cells (TIMC) and by keratinocytes (KC) was investigated in material obtained from the oral mucosal tissues of patients with oral lichen planus (OLP). Peripheral blood mononuclear cells (PBMC) and chronically inflamed and noninflamed gingival KC (CIG-KC, NOR-KC, respectively) were used as the controls. Compared to NOR-KC and CIG-KC, KC from OLP patients (OLP-KC) produced much more interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The OLP-KC superiority in the production of these cytokines was more prominent when the KC were cultured in the presence of interleukin-1 beta (IL-1 beta), lipopolysaccharide and phorbol myristate acetate. OLP-KC also produced more monocyte-chemotactic factor(s) which were not inactivated by the antibodies against GM-CSF, macrophage colony-stimulating factor and monocyte chemoattractant protein-1. TIMC in OLP tissues (OLP-TIMC) were superior to PBMC in the generation of IL-6 and GM-CSF. OLP-TIMC were stimulated to produce more TNF-alpha by IL-1 beta, IL-6 and GM-CSF, more IL-6 by IL-1 beta and GM-CSF, and more GM-CSF by IL-1 beta and IL-6 than PBMC. When compared to cytokine generation in TIMC from the chronically inflamed gingivae, more interferon-gamma, IL-6 and TNF-alpha were generated by OLP-TIMC. These results indicate that KC play a critical role in OLP, producing cytokines including monocyte-chemotactic factor(s), and that the cytokines produced by TIMC and OLP-KC through autocrine and paracrine processes enhance the local inflammatory response.

Detection of monocyte chemotactic and activating factor (MCAF) in normal blood and urine using a sensitive ELISA

We developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) for human monocyte chemotactic and activating factor (MCAF), an inflammatory cytokine that plays an important role in the recruitment of blood monocytes to areas of inflammation. The ELISA, which is based on a sandwich method using two newly-developed monoclonal antibodies, could quantitatively detect MCAF in the range between 2.5 pg/ml (50 fg/sample) to 300 pg/ml after incubation for a total of 2 h, and showed no cross-reactivity with various structurally-related IL-8 superfamily proteins. It was not affected by blood or urine components non-specifically, and thus was directly applicable to clinical specimens. When serum and urine samples from healthy subjects were measured, they all turned out to contain detectable levels of MCAF (more than 30 pg/ml). By gel-filtration column chromatography analysis, MCAF in the body fluids was eluted as a single peak at the position corresponding to the molecular weight of 10 kD, suggesting that it exists as a monomer form, free from carrier proteins. The established ELISA here is expected to be effectively used for the further investigations on the relationship of MCAF with various inflammatory diseases.

Expression of monocyte chemoattractant protein 1 (MCP-1) in adult periodontal disease: increased monocyte chemotactic activity in crevicular fluids and induction of MCP-1 expression in gingival tissues

The present study shows that monocyte chemotactic activity in crevicular fluids increases with severity of the disease and that a monocyte chemoattractant, monocyte chemoattractant protein 1 (MCP-1), is expressed as the predominant cytokine of gingival tissues and their fibroblasts treated with Porphyromonas (Bacteroides) gingivalis lipopolysaccharide (P-LPS). High monocyte chemotactic activity in the crevicular fluids was neutralized significantly by antiserum specific for the JE/MCP-1 protein. Marked expression of the MCP-1 gene was observed in the gingival tissues of all adult periodontal patients tested, but not in those of healthy subjects. Monocyte chemotactic activity was observed in culture supernatants of human normal gingival tissues treated with P-LPS, and the chemotactic activity increased in a dose-related manner. Expression of MCP-1 in P-LPS-treated human gingival fibroblasts was further examined. P-LPS induced the MCP-1 gene expression in a dose- and treatment time-dependent manner. The MCP-1 gene product in the culture supernatant was detected as two forms with molecular masses of 11,000 and 15,000 Da by immunoprecipitation with the specific antiserum. The MCP-1 gene expression was induced in the fibroblasts treated with interleukin-1 beta and tumor necrosis factor alpha, but not with interleukin-6. These results suggest that gingival fibroblasts can participate in monocyte recruitment in gingival tissues of adult periodontal patients via the MCP-1 gene product and that MCP-1 plays an important role in the inflammatory reaction in the disease.

Expression of monocyte chemotactic and activating factor (MCAF) in skin related cells. A comparative study

A significant proportion of the infiltrating cells in several inflammatory skin diseases, including psoriasis and allergic contact dermatitis, are monocytes. Additionally, it is known that the cytokine monocyte chemotactic and activating factor (MCAF) can be produced by several cell types present in the skin, suggesting a significant role for MCAF in the accumulation of monocytes during immunological and inflammatory skin reactions. We have recently developed a precise method for quantification of the amount of a specific mRNA species in a given sample and have used this technique to compare specific MCAF mRNA amounts in cultures of human keratinocytes, dermal fibroblasts, endothelial cells, and monocytes, after stimulation with interleukin 1 alpha (IL-1 alpha) for 6 h. Endothelial cells produced very high, monocytes and fibroblasts intermediate, and keratinocytes low amounts of MCAF mRNA. We have also performed time course studies of MCAF mRNA levels in the four cell types. Our findings suggest that the regulation of MCAF mRNA expression in these cells parallels the regulation of the lymphocyte and neutrophil chemotactic factor interleukin 8.

ETH615, a synthetic inhibitor of leukotriene biosynthesis and function, also inhibits the production of and biological responses towards interleukin-8

ETH615 (4-(2-quinolylmethoxy)-N-(3-fluorobenzyl-phenyl-amino-methyl -4- benzoic-acid), a synthetic inhibitor of leukotriene B4 production and activities, was tested for its effect on the production of and biological responses towards human interleukin-8. We found that ETH615 inhibits lipopolysaccharide-induced (LPS-induced) expression of interleukin-8 messenger-RNA (mRNA) and interleukin-8 production in human peripheral blood mononuclear cells. We also observed that ETH615 completely inhibited interleukin-8 as well as leukotriene B4 directed chemotaxis of human neutrophils in a dose-dependent manner. A moderate effect on fMLP-directed neutrophil chemotaxis was observed. Further, no significant effect on either interleukin-8, leukotriene B4 or fMLP-directed T-cell migration was observed. These results further support the concept of a cytokine-leukotriene regulatory circuit and encourage the establishment of clinical trials testing the effect of ETH615 on inflammatory skin diseases, which are characterized by high levels of interleukin-8 and leukotriene B4 in lesional skin.