Cytokine-activated human endothelial cells synthesize and secrete a monocyte chemoattractant, MCP-1/JE.

We have demonstrated inducible expression of the mRNA encoding the monocyte chemoattractant MCP-1, the human homolog of the JE gene, in endothelial cells within 3 hours of treatment with IL-1 beta and tumor necrosis factor. IFN-gamma also induced expression of this mRNA after 24 hours, but to a lesser extent. MCP-1/JE protein steadily accumulated in the medium of endothelial cells during a 48-hour exposure to IL-1 beta. Medium conditioned by IL-1 beta-treated endothelial cells contained monocyte chemoattractant activity that was immunoadsorbed by anti-MCP-1 antibodies. These results suggest that endothelial cells secrete a monocyte chemoattractant, MCP-1/JE, in response to inflammatory mediators, and thus may contribute to the accumulation of monocytes at sites of inflammation.     

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.     

Production of monocyte chemoattractant protein-1 by malignant fibrous histiocytoma: relation to the origin of histiocyte-like cells.

Human malignant fibrous histiocytoma (MFH) comprise both fibroblast-like cells and histiocyte-like cells. We previously showed that the latter are not neoplastic cells, but are infiltrating macrophages. Since migration of blood monocytes into the tumor might be a response to a locally elaborated monocyte chemoattractant, we designed experiments to determine if the fibroblast-like tumor cells produced a chemoattractant for human monocytes. Malignant fibrous histiocytoma from three patients was put into culture. Cells of all three lines had a spindle shape, and showed no reactivity with antibodies against macrophages (MAC387), HLA-DR (LN3), or leukocyte common antigen. Immunohistochemically, they stained with antibody against human monocyte chemoattractant protein-1 (MCP-1). Culture supernatants of the three cell lines had chemotactic activity for monocytes. This activity was due to MCP-1, since it was absorbed by an anti-MCP-1 column. The production of MCP-1 by MFH tumor lines was confirmed by immunoprecipitation of metabolically labeled MCP-1. These results suggest that the histiocyte-like cells are the infiltrated macrophages that originate from blood monocytes attracted by tumor-derived MCP-1.     

Potential role for monocyte chemotactic protein-4 (MCP-4) in monocyte/macrophage recruitment in acute renal inflammation

The CC chemokine, monocyte chemoattractant protein-4 (MCP-4), is an important chemoattractant for monocytes and T cells. Recent data indicate a role in renal inflammation. This study has used in situ hybridization and immunohistochemical analysis of cryostat sections of biopsy material taken from patients with acute renal allograft rejection and vasculitic glomerulonephritis to demonstrate renal expression of MCP-4, both at message and protein level. MCP-4 was primarily expressed at peritubular, periglomerular, and perivascular sites, irrespective of the inflammatory condition, and was associated with infiltrating CD3-positive lymphocytes and CD68-positive monocyte/macrophages. In addition, proximal tubular epithelial cells grown in culture from cortical fragments of human kidney showed low levels of constitutive MCP-4 expression, detectable by western blotting; this expression of MCP-4 was up-regulated in response to the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). CCR3-, CCR5- and CCR2-expressing leukocyte populations were identified at sites of MCP-4 expression. Double-staining techniques revealed that CC chemokine receptor-expressing cells were primarily CD68-positive. These studies suggest an important role for MCP-4 in the recruitment and retention of monocytes/macrophages in renal inflammation.     

Cysteinyl leukotrienes induce monocyte chemoattractant protein 1 in human monocytes/macrophages

BACKGROUND: Monocytes/macrophages have a cysteinyl leukotriene 1 (CysLT1) receptor, but its function is poorly understood. Objective To elucidate the biological function of the CysLT1 receptor of human monocytes/macrophages. METHODS: We examined the production of TNF-alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, monocyte chemoattractant protein 1 (MCP-1), macrophage colony-stimulating factor (M-CSF), and eotaxin induced by CysLTs (leukotriene (LT)C4, -D4, and -E4) in THP-1 cells, a human monocytic leukaemia cell line, and peripheral blood CD14+ monocytes/macrophages. Moreover, we examined the effect of CysLTs on the expression of beta-chemokine receptor 2B (CCR2B) as the receptor of MCP-1 by Western blot analysis. RESULTS: ELISA revealed that CysLTs induced MCP-1 in THP-1 cells and peripheral blood CD14+ monocytes/macrophages, but not other cytokines. PCR demonstrated that CysLTs increased MCP-1 mRNA expression in THP-1 cells, and Western blotting showed that CysLTs increased the expression of CCR2B in THP-1 cells. Moreover, we demonstrated that pranlukast, a CysLT1 receptor antagonist, blocked MCP-1 production by CysLTs in THP-1 cells almost completely, and partially inhibited MCP-1 release by CysLTs in peripheral blood CD14+ monocytes/macrophages and CCR2B expression by CysLTs in THP-1 cells. CONCLUSION: CysLTs induce MCP-1 and increase CCR2B expression in human monocytes/macrophages.     

Synergistic enhancement of cytokine-induced human monocyte matrix metalloproteinase-1 by C-reactive protein and oxidized LDL through differential regulation of monocyte chemotactic protein-1 and prostaglandin E2

C-reactive protein (CRP) and oxidized LDL (ox-LDL) are associated with inflammatory lesions, such as coronary artery disease, in which monocytes and matrix metalloproteinases (MMPs) may play a major role in the rupture of atherosclerotic plaques. Monocytes are recruited to inflammation sites by monocyte chemoattractant protein-1 (MCP-1), which may also participate in the activation of monocytes. The objective of this study was to compare the individual and combined effect of CRP and ox-LDL on human monocyte MMP-1 and the role of MCP-1 in this effect. Although CRP or ox-LDL failed to induce MMP-1 in control monocytes, these molecules enhanced MMP-1 production induced by tumor necrosis factor alpha (TNF-alpha) and granulocyte macrophage-colony stimulating factor (GM-CSF) with a synergistic increase in MMP-1 occurring in the presence of both mediators. Enhancement of MMP-1 by CRP and ox-LDL was attributable to a differential increase in MCP-1 and prostaglandin E2(PGE2). CRP, at physiological concentrations, induced high levels of MCP-1 and relatively low levels of PGE2, whereas ox-LDL caused a significant enhancement of PGE2 with little affect on MCP-1. Accordingly, CRP- and ox-LDL-induced MMP-1 production by monocytes was inhibited by anti-MCP-1 antibodies and indomethacin, respectively. Moreover, addition of exogenous MCP-1 or PGE2 enhanced MMP-1 production by TNF-alpha- and GM-CSF-stimulated monocytes. These results show that the combination of CRP and ox-LDL can cause a synergistic enhancement of the role of monocytes in inflammation, first, by increasing MCP-1, which attracts more monocytes and directly enhances MMP-1 production by activated monocytes, and second, by elevating PGE2 production, which also leads to higher levels of MMP-1.     

Thrombin Regulates Chemokine Induction during Human Retinal Pigment Epithelial Cell/Monocyte Interaction

Thrombin, an important clotting factor, extravasates at sites of blood-retina barrier breakdown that is often associated with many retinal diseases. Here we investigated the effects of thrombin on human retinal pigment epithelial (HRPE) cells, monocytes, and HRPE cell/monocyte co-cultures. Thrombin induced secretion and mRNA expression of HRPE interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1). Thrombin also enhanced IL-8 and MCP-1 by HRPE cell/monocyte co-cultures, by apparently enhancing cell-cell contact mechanisms. The thrombin effects on IL-6 secretion were similar to those on chemokine secretion. Thrombin-induced chemokines by co-cultures were inhibited by anti-tumor necrosis factor-alpha (TNF-alpha) antibody, but not by anti-IL-1beta antibody. TNF-alpha was detected in cell lysates of monocytes detached from HRPE cells after co-culture stimulation with thrombin. HRPE cells mainly produced these chemokines. However, thrombin generally potentiated exogenous IL-1beta- and TNF-alpha-induced chemokine production by HRPE cells, monocytes, and co-cultures. Interferon-gamma potentiated chemokine secretion by co-cultures with or without thrombin. Our results indicate that thrombin may cause leukocyte recruitment by inducing HRPE cell and monocyte chemokine and by enhancing HRPE cell/monocyte interactions, in part because of monocyte TNF-alpha induction, suggesting important mechanisms for ocular inflammation during blood-retina barrier breakdown and intra-ocular hemorrhage.     

An anti-inflammatory drug, propagermanium, may target GPI-anchored proteins associated with an MCP-1 receptor, CCR2.

Monocyte chemoattractant protein-1 (MCP-1) promotes the migration and activation of monocytes and plays a pivotal role in the development of chronic inflammation. Propagermanium (3-oxygermylpropionic acid polymer) has been used as a therapeutic agent against chronic hepatitis B in Japan. We report here that propagermanium specifically inhibits in vitro chemotactic migration of monocytes by MCP-1. Propagermanium did not inhibit binding of MCP-1 to a human monocytic cell line, THP-1 cells, or affect intracellular Ca(2+) mobilization or the cAMP concentration in MCP-1-treated THP-1 cells. The effect of propagermanium seems to require glycosylphosphatidylinositol (GPI)-anchored proteins, as cleavage of GPI anchors by phosphatidylinositol-phospholipase C (PI-PLC) eliminated the inhibitory activity of propagermanium. Anti-GPI-anchored protein antibodies, such as anti-CD55 and anti-CD59, reduced staining of C-C chemokine receptor 2 (CCR2) with an anti-CCR2 antibody against the N-terminus of CCR2 in a flow cytometric analysis, and these antibodies also selectively inhibited MCP-1-induced migration of THP-1 cells. Furthermore, under fluorescence microscopy, GPI-anchored proteins colocalized with CCR2 on THP-1 cells. These results suggest that propagermanium may target GPI-anchored proteins that are closely associated with CCR2 to selectively inhibit the MCP-1-induced chemotaxis, thus providing a mechanistic basis for the anti-inflammatory effects of the drug.     

单核细胞趋化蛋白-1与糖尿病肾病

单核细胞趋化蛋白-1(MCP-1)是一种特异性趋化因子，在糖尿病肾病 (diabetic nephropathy，DN)的发生发展中起重要作用。代谢性因素如高糖（HG）、糖基化白蛋白（glycated albumin， Gly-Alb）、氧化应激，蛋白激酶C(protein kinase C，PKC)等和血流动力学因素如肾素-血管紧张素系统（RAS）等均可上调肾小球内皮细胞、系膜细胞 (mesangial cell，MC)、小管上皮细胞（tubulus epithelial cells，TECs）中MCP-1基因和蛋白的表达，使单核/巨噬细胞在肾组织中聚集，通过多种机制引起肾脏损伤。     

Camostat mesilate attenuates pancreatic fibrosis via inhibition of monocytes and pancreatic stellate cells activity

Camostat mesilate (CM), an oral protease inhibitor, has been used clinically for the treatment of chronic pancreatitis in Japan. However, the mechanism by which it operates has not been fully understood. Our aim was to evaluate the therapeutic efficacy of CM in the experimental pancreatic fibrosis model induced by dibutyltin dichloride (DBTC), and we also determined the effect of CM on isolated monocytes and panceatic stellate cells (PSCs). In vivo, chronic pancreatitis was induced in male Lewis rats by single administration of 7 mg/kg DBTC and a special diet containing 1 mg/g CM was fed to the DBTC+CM-treated group from day 7, while the DBTC-treated group rats were fed a standard diet. At days 0, 7, 14 and 28, the severity of pancreatitis and fibrosis was examined histologically and enzymologically in both groups. In vitro, monocytes were isolated from the spleen of a Lewis rat, and activated with lipopolysaccharide stimulation. Thereafter, the effect of CM on monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) production from monocytes was examined. Subsequently, cultured rat PSCs were exposed to CM and tested to see whether their proliferation, MCP-1 production and procollagen alpha1 messenger RNA expression was influenced by CM. In vivo, the oral administration of CM inhibited inflammation, cytokines expression and fibrosis in the pancreas. The in vitro study revealed that CM inhibited both MCP-1 and TNF-alpha production from monocytes, and proliferation and MCP-1 production from PSCs. However, procollagen alpha1 expression in PSCs was not influenced by CM. These results suggest that CM attenuated DBTC-induced rat pancreatic fibrosis via inhibition of monocytes and PSCs activity.     

Murine cytomegalovirus infection markedly reduces serum MCP-1 levels in MCP-1 transgenic mice

Monocyte chemoattractant protein-1 (MCP-1) is a pro-inflammatory chemokine believed to play a major role in atherogenesis. Injured endothelial cells express MCP-1, which attracts monocytes to the blood vessel wall and leads to the formation of atheromas. Cytomegalovirus infection may also play a role in atherogenesis and accelerates inflammation in tissues that overexpress MCP-1. To examine the relationship of cytomegalovirus infection and MCP-1, we infected MCP-1 transgenic mice with murine cytomegalovirus (MCMV) and collected serum 6 days post-infection to evaluate TH1-related cytokine levels by ELISA. Serum levels of IL-10, IL-12 and IFN-gamma were increased in MCP-1 transgenic mice on day 6 following MCMV infection, while levels of IL-1beta and TNF-alpha were undetectable. However, MCP-1 serum levels were reduced >50% in MCP-1 transgenic mice following MCMV infection compared to uninfected transgenic mice. This effect was not as dramatic when an M33 null MCMV was administered to MCP-1 transgenic mice. The mechanism by which MCMV lowers serum MCP-1 levels is unknown, but this effect may enhance the survival of the virus and thus allow CMV to contribute to the chronic inflammation of atherogenesis.     

Induction of monocyte chemoattractant protein-1 (MCP-1) production by Pseudomonas nitrite reductase in human pulmonary type II epithelial-like cells

Monocyte chemoattractant protein-1 (MCP-1), a chemoattractant for monocytes, is presumed to play a pivotal role in the recruitment and accumulation of monocytes in various diseases including pulmonary infections. We examined here whether or not Pseudomonas nitrite reductase (PNR), a recently identified IL-8 inducer in various respiratory cells, could stimulate human pulmonary type II epithelial-like cells (A549) to induce MCP-1 production. A time- and dose-dependent induction of MCP-1 protein synthesis associated with an increase of MCP-1 mRNA expression by A549 cells was observed in response to PNR. New protein translation was not required for PNR-mediated MCP-1 mRNA expression in the same cells. When anti-human MCP-1 monoclonal antibody was used for neutralizing of monocyte chemotactic factor (MCF) activities in the culture supernatants of these cells stimulated with PNR, significant reductions of MCF activities (the mean reduction rate; 49-59%, P<0. 05) were observed. These data suggest that PNR may contribute to monocyte migration, through inducing pulmonary epithelial cell-derived MCP-1 production in the airway of patients with pneumonia due to P. aeruginosa.     

Expression of monocyte chemotactic protein-1 in human melanoma in vivo.

A common feature of human melanoma is infiltration by monocytes at early stages of tumorigenesis. This infiltration may be highly significant since macrophages have the capacity to alter the behavior of tumor cells. The authors previously demonstrated that the predominant monocyte chemoattractant produced by tumor cells in vitro was monocyte chemotactic protein-1 (MCP-1). The authors identify the expression of MCP-1 in pathologic specimens of both primary and metastatic human melanoma but not in normal skin. The finding that MCP-1 is produced by malignant melanoma suggests that specific genes are expressed in tumor cells that can induce the recruitment of monocytes in vivo.     

Endogenous MCP-1 promotes lung inflammation induced by LPS and LTA

Monocyte chemoattractant protein 1 (MCP-1) plays an important role in leukocyte recruitment to sites of infection and inflammation. In addition, MCP-1 may attenuate inflammation by virtue of its capacity to inhibit the production of proinflammatory cytokines. We here investigated the role of MCP-1 in lung inflammation induced by lipopolysaccharide (LPS) or lipoteichoic acid (LTA), constituents of the gram-negative and gram-positive bacterial cell wall, respectively. Healthy humans demonstrated elevated MCP-1 concentrations in their bronchoalveolar lavage fluid (BALF) 6h after inhalation of LPS. Similarly, intranasal administration of LPS or LTA to mice resulted in a rise in BALF MCP-1 levels. Murine alveolar macrophage-like cells released significant amounts of MCP-1 upon stimulation with LPS or LTA in vitro. Compared to Wt mice, MCP-1(-/-) mice demonstrated lower TNF-α levels and a diminished neutrophil influx into their bronchoalveolar space after either LPS or LTA instillation. After intrapulmonary delivery of LPS MCP-1(-/-) mice had decreased interleukin-6 and KC concentrations and less severe lung inflammation upon histopathological examination. Remarkably, MCP-1 deficiency was associated with an early enhancement of interleukin-10 release in BALF after both LPS and LTA instillation. These data suggest that MCP-1 is a proinflammatory mediator during pulmonary inflammation induced by either LPS or LTA.     

Interaction of Bartonella henselae with endothelial cells promotes monocyte/macrophage chemoattractant protein 1 gene expression and protein production and triggers monocyte migration

Bacillary angiomatosis (BA), one of the many clinical manifestations resulting from infection with the facultative intracellular bacterium Bartonella henselae, is characterized by angiogenic lesions. Macrophages have been identified as important effector cells contributing to the angiogenic process during B. henselae infection by infiltrating BA lesions and secreting vascular endothelial growth factor. Monocyte-macrophage chemoattractant protein 1 (MCP-1) recruits macrophages to sites of inflammation. In this study, we investigated the ability of B. henselae to upregulate MCP-1 gene expression and protein production in the human microvascular endothelial cell line HMEC-1. MCP-1 mRNA was induced at 6 and 24 h after treatment with bacteria, whereas protein production was elevated at 6, 24, and 48 h. This induction was not dependent on the presence of bacterial lipopolysaccharide or endothelial cell toll-like receptor 4. However, MCP-1 production was dependent on NF-kappaB activity. Outer membrane proteins of low molecular weight were able to upregulate MCP-1 production. Furthermore, supernatants from B. henselae-infected HMEC-1 were able to induce chemotaxis of THP-1 monocytes. These data suggest a mechanism by which the macrophage effector cell is recruited to the endothelium during B. henselae infection and then contributes to bacterial-induced angiogenesis.     

Actinobacillus actinomycetemcomitans serotype b-specific polysaccharide antigen stimulates production of chemotactic factors and inflammatory cytokines by human monocytes.

Serotype b-specific polysaccharide antigen (SPA) was extracted from whole cells of Actinobacillus actinomycetemcomitans Y4 by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300. SPA induced the release of monocyte and leukocyte chemotactic factors by human monocytes. Polymyxin B had almost no effect on the release of monocyte chemotactic factor, but a monoclonal antibody against SPA markedly inhibited it. Human monocytes stimulated with SPA exhibited the increased mRNA expression of monocyte chemoattractant protein 1 (MCP-1) and a neutrophil chemotactic factor, interleukin-8 (IL-8). On the other hand, SPA induced the release of IL-1, IL-6, and tumor necrosis factor (TNF) and enhanced the expression of IL-1alpha, IL-1beta, IL-6, and TNF alpha (TNF-alpha) mRNAs. Human monocytes expressed MCP-1 and IL-8 mRNAs when stimulated by human recombinant IL-1alpha, I1-1beta, IL-6, and TNF-alpha, suggesting that these inflammatory cytokines induced by SPA might participate in the production of chemotactic factors in human monocytes.     

MCP-1在胚胎种植中的作用

趋化因子是一类对中性粒细胞、单核细胞、嗜碱性粒细胞等起趋化和激活作用的多功能糖蛋白,介导炎症和免疫反应,单核细胞趋化蛋白-1（MCP-1）属于CC类趋化因子家族的一员。近年来研究表明,在激素的调节作用下,MCP-1在胚胎种植中发挥重要作用,其机制主要为趋化并激活单核巨噬细胞,参与Th2型免疫偏移及促进血管生成。