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1.
Recent reports indicate that murine CD4+ Th1-type cloned T cells are insensitive to IL-1 because specific IL-1R are not detected on these cells and IL-1 does not modulate proliferative responses. However, we have determined that Th1 clones can respond to IL-1, because they function synergistically with IL-2 to induce granulocyte-macrophage-CSF secretion. This response to IL-1 plus IL-2 could be induced by IL-1 alpha or IL-1 beta and by membrane-bound IL-1 on macrophages. However, IL-1R could not be detected, and Th1 cells did not respond to IL-4 in the presence or absence of IL-1, as measured by either proliferation or granulocyte-macrophage-CSF production. Therefore, IL-1 functioned as a cofactor in Th1 cells stimulated with IL-2, but not with IL-4. A possible mechanism whereby IL-1 activates Th1 cells is discussed.  相似文献   

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Matrix metalloproteinase-9 (MMP-9) may play a critical catalytic role in tissue remodeling in vivo, but it is secreted by cells as a stable, inactive zymogen, pro-MMP-9, and requires activation for catalytic function. A number of proteolytic enzymes activate pro-MMP-9 in vitro, but the natural activator(s) of MMP-9 is unknown. To examine MMP-9 activation in a cellular setting we employed cultures of human tumor cells (MDA-MB-231 breast carcinoma cells) that were induced to produce MMP-9 over a 200-fold concentration range (0.03-8.1 nM). The levels of tissue inhibitors of metalloproteinase (TIMPs) in the induced cultures remain relatively constant at 1-4 nM. Quantitation of the zymogen/active enzyme status of MMP-9 in the MDA-MB-231 cultures indicates that even in the presence of potential activators, the molar ratio of endogenous MMP-9 to TIMP dictates whether pro-MMP-9 activation can progress. When the MMP-9/TIMP ratio exceeds 1.0, MMP-9 activation progresses, but through an interacting protease cascade involving plasmin and stromelysin 1 (MMP-3). Plasmin, generated by the endogenous urokinase-type plasminogen activator, is not an efficient activator of pro-MMP-9, neither the secreted pro-MMP-9 nor the very low levels of pro-MMP-9 associated with intact cells. Although plasmin can proteolytically process pro-MMP-9, this limited action does not yield an enzymatically active MMP-9, nor does it cause the MMP-9 to be more susceptible to activation. Plasmin, however, is very efficient at generating active MMP-3 (stromelysin-1) from exogenously added pro-MMP-3. The activated MMP-3 becomes a potent activator of the 92-kDa pro-MMP-9, yielding an 82-kDa species that is enzymatically active in solution and represents up to 50-75% conversion of the zymogen. The activated MMP-9 enhances the invasive phenotype of the cultured cells as their ability to both degrade extracellular matrix and transverse basement membrane is significantly increased following zymogen activation. That this enhanced tissue remodelling capability is due to the activation of MMP-9 is demonstrated through the use of a specific anti-MMP-9 blocking monoclonal antibody.  相似文献   

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Human leukocyte antigen-G (HLA-G) molecules are non-classical HLA class I antigens with an important role in pregnancy immune regulation and inflammation control. Soluble HLA-G proteins can be generated through two mechanisms: alternative splicing and proteolytic release, which is known to be metalloprotease mediated. Among this class of enzymes, matrix metalloproteinases (MMPs) might be involved in the HLA-G1 membrane cleavage. Of particular interest are MMP-2 and MMP-9, which regulate the inflammatory process by cytokine and chemokine modulation. We evaluated the effect of MMP-9 and MMP-2 on HLA-G1 membrane shedding. In particular, we analyzed the in vitro effect of these two gelatinases on the secretion of HLA-G1 via proteolytic cleavage in 221-G1-transfected cell line, in JEG3 cell line, and in peripheral blood mononuclear cells. The results obtained by both cell lines showed the role of MMP-2 in HLA-G1 shedding. On the contrary, MMP-9 was not involved in this process. In addition, we identified three possible highly specific cleavage sites for MMP-2, whereas none were detected for MMP-9. This study suggests an effective link between MMP-2 and HLA-G1 shedding, increasing our knowledge on the regulatory machinery beyond HLA-G regulation in physiological and pathological conditions.  相似文献   

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The zinc-dependent gelatinases belong to the family of matrix metalloproteinases (MMPs), enzymes that have been shown to play a key role in angiogenesis and tumor metastasis. These enzymes are capable of hydrolyzing extracellular matrix (ECM) components under physiological conditions. Specific and selective inhibitors aimed at blocking their activity are highly sought for use as potential therapeutic agents. We report herein on a novel mode of inhibition of gelatinase A (MMP-2) by the recently characterized inhibitors 4-(4-phenoxphenylsulfonyl)butane-1,2-dithiol (inhibitor 1) and 5-(4-phenoxphenylsulfonyl) pentane-1,2-dithiol (inhibitor 2). These synthetic inhibitors are selective for MMP-2 and MMP-9. We show that the dithiolate moiety of these inhibitors chelates the catalytic zinc ion of MMP-2 via two sulfur atoms. This mode of binding results in alternation of the coordination number of the metal ion and the induction of conformational changes at the microenvironment of the catalytic zinc ion; a set of events that is likely to be at the root of the potent slow binding inhibition behavior exhibited by these inhibitors. This study demonstrates a distinct approach for the understanding of the structural mechanism governing the molecular interactions between potent inhibitors and catalytic sites of MMPs, which may aid in the design of effective inhibitors.  相似文献   

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Altered contractility of airway smooth muscle (SM) is one of the main causes of allergic asthma, in which the predominance of Th2 over Th1 cytokines plays a central role. In the present study, we examine the effects of Th2 cytokines on airway SM contraction. Treatment with a low concentration of IL-4 (0.2 ng/ml) for 6 h augmented, whereas higher concentrations (2-20 ng/ml) inhibited, agonist-induced contractions of collagen gels containing bovine tracheal SM cells. Another Th2 cytokine (IL-13) showed an augmentation of gel contraction in the concentration range of 20-200 ng/ml. IL-4 and IL-13 increased mRNA expression and protein secretion of matrix metalloproteinase (MMP)-1, but these cytokines did not affect Ca(2+)-mobilizing properties and phosphorylation levels of myosin L chain in bovine tracheal SM cells. These changes were sensitive to wortmannin, an inhibitor of PI3K, but not to leflunomide, an inhibitor of STAT6. Scanning electron microscope observation revealed that collagen fibers twining around SM cells were completely dissolved in 20 ng/ml IL-4-treated gels and reorganized into basket-like structure in 20 ng/ml IL-13-treated gels. Exogenous application of high and low concentrations of MMP-1 also induced the inhibition and augmentation of gel contraction, respectively. Furthermore, nonselective MMP inhibitor galardin suppressed the effects of IL-4 and IL-13 on gel contraction, and MMP-1-targeted small-interfering RNA reversed the inhibitory effects of IL-4 on gel contraction to the augmentation. This indicates that Th2 cytokines modulate airway contraction without affecting cellular contractility but by secreting MMP-1 from the SM cells via PI3K activation and changing cell-to-matrix interactions.  相似文献   

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Carbamylation refers to chemical modification of protein side chains by cyanate derived e.g. from urea. It alters their structural and functional properties. We have studied the influence of the carbamylation of type I collagen in vitro on its interactions with elutriated human monocytes, and its potential role in atherosclerosis. Adhesion of monocytes onto carbamylated collagen was significantly enhanced compared to native collagen. There was no change in superoxide anion production. On the other hand, there was an increase in the production and the activation of matrix metalloproteinase-9. No effect was found on tissue inhibitor of metalloproteinase-1 production. Thus, the presence of carbamylated collagen may stimulate the remodelling of extracellular matrix mediated by activated monocytes. Such alterations may contribute to enhanced atherosclerosis in renal insufficiency, a pathological condition associated with elevated levels of carbamylation.  相似文献   

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Granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF enhance phagocyte survival and function and are produced by fibroblasts and endothelial cells after induction by inflammatory mediators such as IL-1. Our ability to detect G-CSF and GM-CSF activity in the conditioned medium of the human astroglial tumor cell line, U87MG, and molecularly clone the cDNA for G-CSF from a U87MG cDNA library raised the possibility that astroglial cells are capable of G-CSF and GM-CSF production within the central nervous system; if so, the production of these CSF by astroglial cells may be inducible by IL-1. We examined the effects of IL-1 alpha and IL-1 beta on the production of G-CSF and GM-CSF by U87MG and U373MG, another astroglial tumor cell line that does not constitutively produce CSF. We demonstrate that both U87MG and U373MG can be induced to produce G-CSF and GM-CSF by exposure to IL-1 alpha and IL-1 beta. This response, measured by accumulation of increased CSF mRNA, is rapid, sensitive and due to the enhanced stability of CSF message following IL-1 exposure. The implications of these findings to the immunopathogenesis of central nervous system infections are discussed.  相似文献   

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Thrombospondin-1 (TSP-1) is a 450 kDa matrix bound glycoprotein involved in tumor invasion, metastasis, and angiogenesis. One of the receptors involved in TSP-1 mediated tumor cell adhesion and metastasis is the cysteine-serine-valine-threonine-cysteine-glycine (CSVTCG) receptor. One mechanism of TSP-1 in promoting tumor cell metastasis involves the up-regulation of matrix metalloproteinase-9 (MMP-9) expression, specifically through the CSVTCG TSP-1 receptor. TSP-1 and its CSVTCG receptor has been implicated in tumor progression in a variety of cancers including breast adenocarcinomas, head and neck squamous cell carcinomas, and pancreatic carcinomas. In this study, we examined 99 cases of colorectal cancer by immunohistochemical analysis to investigate 1) the localization of TSP-1 and CSVTCG TSP-1 receptor, 2) the relationship with MMP-9, and 3) the correlation of expression with clinical staging. Strong expression of TSP-1 was observed in the submucosa or the serosa adjacent to the tumor. Positive staining for CSVTCG TSP-1 receptor was observed in tumor cells and microvessels. MMP-9 was also expressed in tumor cells. In addition, staining intensity of CSVTCG TSP-1 receptor was higher in poorly differentiated adenocarcinoma than well or moderately differentiated adenocarcinoma. Tumors in which inflammatory cells stained strongly for CSVTCG TSP-1 receptor correlated with decreased incidence of distant metastasis and angiogenesis. These data were consistent with our previous studies for breast, pancreatic, and head and neck carcinoma. They suggest an important role for TSP-1 and CSVTCG TSP-1 receptor in tumor progression in colorectal cancer.  相似文献   

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IL-4 enhances programmed cell death (apoptosis) in stimulated human monocytes.   总被引:14,自引:0,他引:14  
Because IL-4 down-regulates several proinflammatory functions associated with human monocytes/macrophages, we explored the possibility that IL-4 also decreases monocyte survival. IL-4 caused a concentration-dependent decrease in viability of IL-1 or LPS stimulated, but not unstimulated, monocytes. Nonviable cells demonstrated classic features of programmed cell death or apoptosis, in that they were condensed and contained oligonucleosome-sized (200 bp) DNA fragments. When compared with several other cytokines commonly associated with inflammatory lesions, IL-4 was uniquely effective in enhancing cell death. We found that IL-4 enhanced death more quickly in IL-1-stimulated cells than in LPS-stimulated cells, that stimulated monocytes did not become resistant to the effects of IL-4 during culture, and that the effects of IL-4 on viability were antagonized by IFN-gamma. Enhanced cell death was stimulus-specific in that monocyte viability maintained by certain activating agents, such as Con A or CSF, was unaffected by IL-4. These findings represent the first evidence of cytokine-enhanced programmed cell death in monocytes and suggest that the antiinflammatory effects of IL-4 are mediated in part by reducing survival of stimulated monocytes in chronic lesions.  相似文献   

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Growth of the kidney is a complex process piloted by the collecting duct (CD) ampullae. The dichotomous arborisation and consecutive elongation of this tubular element determines the exact site and time for the induction of nephrons in the overlaying mesenchymal cap condensates. The mechanism by which the CD ampullae find the correct orientation is currently unknown. Recently, we have demonstrated micro-fibres that originate from the basal aspect of the CD ampullae and extend through the mesenchyme to the organ capsule. The micro-fibres are assumed to be involved in the growth and arborisation process of the CD ampulla. Therefore, we have investigated the specific distribution of the micro-fibres during branching morphogenesis. We have also analysed whether the micro-fibres co-localise with extracellular matrix (ECM)-modulating enzymes and whether the co-localisation pattern changes during CD ampulla arborisation. Micro-fibres were detected in all stages of CD ampulla arborisation. Tissue transglutaminase (Tgase2) co-localised with soybean agglutinin (SBA)-positive micro-fibres, whose presence depended upon the degree of CD branching. Matrix metalloproteinase-9 (MMP-9) also co-localised with micro-fibres, but its expression pattern was different from that for Tgase2. Western blotting experiments demonstrated that Tgase2 and MMP-9 co-migrated with SBA-labelled proteins. Thus, the micro-fibres are developmentally modulated by enzymes of the ECM in embryonic kidney cortex. These findings illustrate the importance of micro-fibres in directing CD ampulla growth.  相似文献   

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Cigarette smoke is the major risk factor associated with the development of chronic obstructive pulmonary disease and alters expression of proteolytic enzymes that contribute to disease pathology. Previously, we reported that smoke exposure leads to the induction of matrix metalloproteinase-1 (MMP-1) through the activation of ERK1/2, which is critical to the development of emphysema. To date, the upstream signaling pathway by which cigarette smoke induces MMP-1 expression has been undefined. This study demonstrates that cigarette smoke mediates MMP-1 expression via activation of the TLR4 signaling cascade. In vitro cell culture studies demonstrated that cigarette smoke-induced MMP-1 was regulated by TLR4 via MyD88/IRAK1. Blockade of TLR4 or inhibition of IRAK1 prevented cigarette smoke induction of MMP-1. Mice exposed to acute levels of cigarette smoke exhibited increased TLR4 expression. To further confirm the in vivo relevance of this signaling pathway, rabbits exposed to acute cigarette smoke were found to have elevated TLR4 signaling and subsequent MMP-1 expression. Additionally, lungs from smokers exhibited elevated TLR4 and MMP-1 levels. Therefore, our data indicate that TLR4 signaling, through MyD88 and IRAK1, plays a predominant role in MMP-1 induction by cigarette smoke. The identification of the TLR4 pathway as a regulator of smoke-induced protease production presents a series of novel targets for future therapy in chronic obstructive pulmonary disease.  相似文献   

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A semi-purified fraction obtained from P388 D1 cell line conditioned medium (P388 D1 CM) which contains Interleukin-1 (IL-1) and Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) stimulates murine thymocyte proliferation both in the absence and the presence of a suboptimal dose of phytohemagglutinin (PHA). Because this effect on thymocyte proliferation is always larger than that obtained with optimal concentrations of pure IL-1, we have investigated the possible involvement of GM-CSF in this semi-purified fraction mediated-thymocyte proliferation. We here show that the maximal level of thymocyte proliferation induced by the semi-purified fraction is comparable to that obtained by the co-addition of recombinant GM-CSF and IL-1. In addition, although GM-CSF alone induces no significant thymocyte proliferation, the presence of an anti-GM-CSF antiserum partially blocks the thymocyte proliferation induced by the semi-purified fraction. Thus, the capacity of the semi-purified fraction of P388 D1 to stimulate thymocyte proliferation appears to result from a synergistic action between GM-CSF and IL-1.  相似文献   

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The effect of IL-4 on the IFN-gamma-induced state of activation of cultured human monocytes was investigated with regard to their ability to produce hydrogen peroxide and their antileishmanial capacity towards the intracellular parasite Leishmania donovani. IL-4 was found to inhibit the IFN-gamma-dependent hydrogen peroxide production of monocytes. Treatment of monocytes with IFN-gamma (200 to 600 U/ml) for 48 h increased the hydrogen peroxide production fourfold above background. Coincubation of the monocytes with IL-4 (1 to 1000 U/ml) and IFN-gamma (200 to 600 U/ml) inhibited this increase by 50 to 100%. IL-4 alone did not modulate the hydrogen peroxide production of monocytes. Pretreatment of monocytes with IL-4 for 20 min to 3 h was already effective in preventing the IFN-gamma response. Addition of IL-4 not later than 6 h after the start of incubation with IFN-gamma was necessary for an optimal inhibitory effect. IL-4 also inhibited the IFN-gamma-induced antileishmanial capacity of monocytes: IFN-gamma (1000 U/ml) induced a 54 +/- 10% reduction in the number of parasites. Monocytes treated with combinations of IL-4 (100 to 1000 U/ml) and IFN-gamma (1000 U/ml) were unable to reduce the parasite numbers. IL-4 alone did not alter the uptake of Leishmania donovani nor induce antileishmanial activity. These results demonstrate that IL-4 disables human cultured monocytes to respond to IFN-gamma activation.  相似文献   

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Background  

The aim of this study was to examine the invasiveness of first trimester trophoblasts according to the secretion profile of MMP-2 and -9 at different gestational stages, and to test the similarity between primary trophoblast cell-culture and the JAR choriocarcinoma cell-line.  相似文献   

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