Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10145 (IL-8)
 23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Matrix metalloproteinases (MMPs) are a family of zinc-dependent enzymes, capable of degrading proteins found in the extracellular matrix. MMPs 2 and 9 are known to be produced by microglia, the resident macrophages of the central nervous system. The control of the secretion of these proteases and the activation of proenzymes by other proteases such as plasmin, as well as the balance between MMP secretion and the secretion of their natural inhibitors (TIMPs), have an important relevance in the pathogenesis of multiple sclerosis (MS). The in vitro control of MMPs 2 and 9, TIMPs 1 and 2, and urokinase-type plasminogen activator by microglia was examined in response to a panel of chemokines (chemotactic cytokines), using ELISA and zymography techniques. The chemokines MCP1, MIP1beta, RANTES, IL-8, and Fractalkine were all found significantly to increase the secretion of MMPs and TIMPs by a human foetal microglial cell line, CHME3, after 24 h stimulation. The chemokines tested, MCP1, MIP1beta, and Fractalkine, were also shown to increase MMP9 secretion by primary isolated rat brain microglia in vitro. MCP1, MIP1alpha/beta, and RANTES significantly decreased the secretion of uPA into culture supernatants in ELISA experiments. These findings suggest an important potential role for the involvement of chemokines in the breakdown of the blood-brain barrier and also the destruction of myelin basic protein in MS.
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PMID:Chemokine modulation of matrix metalloproteinase and TIMP production in adult rat brain microglia and a human microglial cell line in vitro. 1055 77

Chemokines are mediators in inflammatory and autoimmune disorders. Aminoterminal truncation of chemokines results in altered specific activities and receptor recognition patterns. Truncated forms of the CXC chemokine interleukin (IL)-8 are more active than full-length IL-8 (1-77), provided the Glu-Leu-Arg (ELR) motif remains intact. Here, a positive feedback loop is demonstrated between gelatinase B, a major secreted matrix metalloproteinase (MMP-9) from neutrophils, and IL-8, the prototype chemokine active on neutrophils. Natural human neutrophil progelatinase B was purified to homogeneity and activated by stromelysin-1. Gelatinase B truncated IL-8(1-77) into IL-8(7-77), resulting in a 10- to 27-fold higher potency in neutrophil activation, as measured by the increase in intracellular Ca(++) concentration, secretion of gelatinase B, and neutrophil chemotaxis. This potentiation correlated with enhanced binding to neutrophils and increased signaling through CXC chemokine receptor-1 (CXCR1), but it was significantly less pronounced on a CXCR2-expressing cell line. Three other CXC chemokines-connective tissue-activating peptide-III (CTAP-III), platelet factor-4 (PF-4), and GRO-alpha-were degraded by gelatinase B. In contrast, the CC chemokines RANTES and monocyte chemotactic protein-2 (MCP-2) were not digested by this enzyme. The observation of differing effects of neutrophil gelatinase B on the proteolysis of IL-8 versus other CXC chemokines and on CXC receptor usage by processed IL-8 yielded insights into the relative activities of chemokines. This led to a better understanding of regulator (IL-8) and effector molecules (gelatinase B) of neutrophils and of mechanisms underlying leukocytosis, shock syndromes, and stem cell mobilization by IL-8. (Blood. 2000;96:2673-2681)
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PMID:Neutrophil gelatinase B potentiates interleukin-8 tenfold by aminoterminal processing, whereas it degrades CTAP-III, PF-4, and GRO-alpha and leaves RANTES and MCP-2 intact. 1102 97

Gelatinase B is a matrix metalloproteinase (MMP-9) expressed under strict control by many cell types including neutrophils, monocytes, macrophages, and tumor cells. MMP-9 is a key mediator in the physiological maintenance of the extracellular matrix both in tissue remodeling and development, while uncontrolled enzyme activity contributes to pathologies such as cancer and inflammation. Neutrophils release MMP-9 from granules in response to IL-8 stimulation. Human MMP-9 has three potential N-linked glycosylation sites and contains a Ser/Pro/Thr rich domain, known as the type V collagen-like domain, which is expected to be heavily O-glycosylated. Indeed, approximately 85% of the total sugars on human neutrophil MMP-9 are O-linked. This paper presents the detailed analysis of picomole amounts of these O-glycans using a novel HPLC-based strategy for O-glycan analysis that provides linkage and arm specific information in addition to monosaccharide sequence. The initial structural assignments were confirmed using HPLC with online MS/MS fragmentation analysis. Twelve sugars were identified that contained from two to nine monosaccharide residues. Most of these contained type 2 core structures with Galbeta1-4GlcNAc (N-acetyl lactosamine) extensions, with or without sialic acid or fucose. The O-glycans were modeled using the oligosaccharide structural database. On the basis of the structure of gelatinase A (MMP-2), a model of MMP-9 suggests that the type V collagen-like domain in gelatinase B is located on a loop remote from the active site. Fourteen potential O-glycosylation sites are multiply presented on this loop of 52 amino acids. Many of the O-glycans identified contain terminal galactose residues that may provide recognition epitopes. Importantly, heavy glycosylation of this loop region, absent in gelatinase A, has considerable implications for the domain organization of MMP-9.
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PMID:O-glycan analysis of natural human neutrophil gelatinase B using a combination of normal phase-HPLC and online tandem mass spectrometry: implications for the domain organization of the enzyme. 1112 94

Matrix metalloproteinase-9 (MMP-9) may play an important role in the development of inflammatory bowel disease (IBD). However, the cellular source of MMP-9 in the inflamed mucosa of IBD remains unclear. Here we report that MMP-9 mRNA is expressed in CaCO-2 cells, an intestinal epithelial cell line, and that its expression is upregulated by inflammatory stimuli. Stimulation of CaCO-2 cells with interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha) led to a dose-dependent increase in expression and secretion of MMP-9. In contrast, bacterial lipopolysaccharide (LPS) failed to induce expression or secretion of MMP-9, suggesting that an inflammatory reaction leading to cytokine release is a necessary step for the induction of MMP-9 release in intestinal epithelial cells. Additional studies show that induction of MMP-9 mRNA peaked at 16 h of IL-1beta stimulation, whereas expression of monocyte chemoattractant protein-1 (MCP-1) and IL-8 both peaked at 3 h of stimulation. Treatment of CaCO-2 cells with rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, significantly reduced secretion of MMP-9, indicating that agents that activate PPAR-gamma may have therapeutic use in patients with IBD.
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PMID:Production of matrix metalloproteinase-9 in CaCO-2 cells in response to inflammatory stimuli. 1124 73

Matrix metalloproteinases (MMPs) form a family of enzymes with major actions in the remodeling of extracellular matrix (ECM) components. Gelatinase B (MMP-9) is the most complex family member in terms of domain structure and regulation of its activity. Gelatinase B activity is under strict control at various levels: transcription of the gene by cytokines and cellular interactions; activation of the pro-enzyme by a cascade of enzymes comprising serine proteases and other MMPs; and regulation by specific tissue inhibitors of MMPs (TIMPs) or by unspecific inhibitors, such as alpha2-macroglobulin. Thus, remodeling ECM is the result of the local protease load, i.e., the net balance between enzymes and inhibitors. Glycosylation has a limited effect on the net activity of gelatinase B, and in contrast to the all-or-none effect of enzyme activation or inhibition, it results in a higher-level, fine-tuning effect on the ECM catalysis by proteases in mammalian species. Fast degranulation of considerable amounts of intracellularly stored gelatinase B from neutrophils, induced by various types of chemotactic factors, is another level of control of activity. Neutrophils are first-line defense leukocytes and do not produce gelatinase A or TIMP. Thus, neutrophils contrast sharply with mononuclear leukocytes, which produce gelatinase A constitutively, synthesize gelatinase B de novo after adequate triggering, and overproduce TIMP-1. Gelatinase B is also endowed with functions other than cleaving the ECM. It has been shown to generate autoimmune neo-epitopes and to activate pro-IL-1beta into active IL-1beta. Gelatinase B ablation in the mouse leads to altered bone remodeling and subfertility, results in resistance to several induced inflammatory or autoimmune pathologies, and indicates that the enzyme plays a crucial role in development and angiogenesis. The major human neutrophil chemoattractant, IL-8, stimulates fast degranulation of gelatinase B from neutrophils. Gelatinase B is also found to function as a regulator of neutrophil biology and to truncate IL-8 at the amino terminus into a tenfold more potent chemokine, resulting in an important positive feedback loop for neutrophil activation and chemotaxis. The CXC chemokines GRO-alpha, CTAP-III, and PF-4 are degraded by gelatinase B, whereas the CC chemokines MCP-2 and RANTES are not cleaved.
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PMID:Gelatinase B functions as regulator and effector in leukocyte biology. 1140 67

SDF-1 is a potent chemoattractant for mature white blood cells and hemopoietic stem/progenitor cells (HPCs). An important role for this chemokine in mobilization has been postulated, but in vivo studies directly addressing its effects are lacking. After one injection of fucan sulfate (FucS) or dextran sulfate, plasma levels of SDF-1 are greatly increased in mice or primates. Increases are dose-dependent and correlate with mobilization of HPCs. Elevated levels of circulating SDF-1 appear to be uniquely associated with this treatment, as it was not seen with cytokine or anti-integrin antibody treatments that induce mobilization. In vitro, these sulfated glycans specifically bind to SDF-1 and inhibit SDF-1/heparin binding, suggesting a mechanism of release from sequestration on heparan sulfate proteoglycans in vivo. Although other chemokines including IL8 and cytokines like G-CSF also increase, evidence in GCSFR-deficient mice suggests that at least these two factors are unlikely participants in FucS-induced mobilization. Likewise, although the activity of the metallo-protease MMP9 increases after FucS treatment, experiments in MMP9-/- mice indicate its presence is dispensable for mobilization or SDF-1 release. However, effects of other proteases cannot be ruled out by these experiments. Finally, anti-SDF-1 antibodies partially inhibit FucS-induced mobilization, supporting a causative relationship. Our data offer a unique insight into the mechanism of sulfated glycan-induced mobilization and suggest a novel way of disturbing SDF-1 gradients between bone marrow and peripheral blood.
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PMID:Increase in circulating SDF-1 after treatment with sulfated glycans. The role of SDF-1 in mobilization. 1145 25

Leukocytosis is a physiopathological mechanism primarily to combat infections, whereas stem cell mobilization is induced for therapeutical purposes. Both processes are dependent on the balance between leukocyte and stem cell retention and mobilization. The retention is mediated by the specific architecture of the bone marrow, adhesion molecules and the production of chemokines in the bone marrow, which attract escaped immature cells to the marrow. Mobilization is the effect of the action of "peripheral" chemokines, such as interleukin-8 (IL-8 or CXCL8) and the remodeling of the matrix and basement membranes by matrix enzymes, such as gelatinase B (MMP-9). Recent studies lead to the conclusion that neutrophils, IL-8/CXCL8 and gelatinase B/MMP-9 play control roles in leukocytosis and stem cell mobilization. Neutrophils are the predominant circulating leukocyte type and IL-8/CXCL8 is the major neutrophil chemoattractant in humans. Gelatinase B and no gelatinase A is rapidly released from prestored granules after activation of neutrophils by IL-8/CXCL8. Moreover, neutrophils do not produce TIMP-1 and can chemically activate latent progelatinase B. Activated gelatinase B catalyses the aminoterminal truncation of IL-8/CXCL8 into a tenfold more potent chemokine. This implies that, when IL-8/CXCL8 appears in the circulation, the bone marrow is instructed to release neutrophils and concomitantly stem cells. These studies suggest that IL-8/CXCL8 and gelatinase B/MMP-9 are targets for the modulation of stem cell mobilization.
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PMID:Neutrophil gelatinase B and chemokines in leukocytosis and stem cell mobilization. 1199 52

All-trans retinoic acid (ATRA) has been shown to induce differentiation of human acute promyelocytic leukaemia (APL) cells and eventual elimination of the malignant clone. Matrix metalloproteinase-9 (MMP-9) is produced by neutrophils and its expression appears to be linked with myeloid cell differentiation. We investigated effects of ATRA on MMP expression in two human myeloid leukaemia cell lines, PL-21 and NB4. Both cells could differentiate into neutrophils after exposure to ATRA. Both the activity and antigen levels of MMP-9 were much higher in NB4 cells than in PL-21 cells. Stimulation with ATRA significantly increased MMP-9 levels approximately three- to fivefold in both PL-21 and NB4-conditioned media. MMP-9 mRNA levels increased in ATRA-treated cells and was almost in parallel with the increase in MMP-9 activity, suggesting that ATRA induced MMP-9 by activating its gene expression. ATRA can induce interleukin 8 (IL-8) in APL cells. IL-8, chemokine for neutrophils and a potent inducer of MMP-9, was also induced by ATRA in PL-21 cells. However, recombinant IL-8 did not induce MMP-9 expression. In addition, a neutralizing antibody against IL-8 did not inhibit ATRA-induced MMP-9 expression in either cell type. These observations suggest that ATRA can induce both MMP-9 and IL-8, but IL-8 is not involved in ATRA-induced MMP-9 expression. As MMP-9 can truncate and activate IL-8, simultaneous induction of MMP-9 and IL-8 by ATRA could activate leucocytes excessively, causing the hyper-inflammatory events in retinoic acid syndrome.
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PMID:Simultaneous induction of matrix metalloproteinase-9 and interleukin 8 by all-trans retinoic acid in human PL-21 and NB4 myeloid leukaemia cells. 1213 25

On chemokine stimulation, leucocytes produce and secrete proteolytic enzymes for innate immune defence mechanisms. Some of these proteases modify the biological activity of the chemokines. For instance, neutrophils secrete gelatinase B (matrix metalloproteinase-9, MMP-9) and neutrophil collagenase (MMP-8) after stimulation with interleukin-8/CXCL8 (IL-8). Gelatinase B cleaves and potentiates IL-8, generating a positive feedback. Here, we extend these findings and compare the processing of the CXC chemokines human and mouse granulocyte chemotactic protein-2/CXCL6 (GCP-2) and the closely related human epithelial-cell derived neutrophil activating peptide-78/CXCL5 (ENA-78) with that of human IL-8. Human GCP-2 and ENA-78 are cleaved by gelatinase B at similar rates to IL-8. In addition, GCP-2 is cleaved by neutrophil collagenase, but at a lower rate. The cleavage of GCP-2 is exclusively N-terminal and does not result in any change in biological activity. In contrast, ENA-78 is cleaved by gelatinase B at eight positions at various rates, finally generating inactive fragments. Physiologically, sequential cleavage of ENA-78 may result in early potentiation and later in inactivation of the chemokine. Remarkably, in the mouse, which lacks IL-8 which is replaced by GCP-2/LIX as the most potent neutrophil activating chemokine, N-terminal clipping and twofold potentiation by gelatinase B was also observed. In addition to the similarities in the potentiation of IL-8 in humans and GCP-2 in mice, the conversion of mouse GCP-2/LIX by mouse gelatinase B is the fastest for any combination of chemokines and MMPs so far reported. This rapid conversion was also performed by crude neutrophil granule secretion under physiological conditions, extending the relevance of this proteolytic cleavage to the in vivo situation.
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PMID:Gelatinase B/MMP-9 and neutrophil collagenase/MMP-8 process the chemokines human GCP-2/CXCL6, ENA-78/CXCL5 and mouse GCP-2/LIX and modulate their physiological activities. 1295 Feb 57

Proteolytic processing is an important regulatory mechanism for chemokines. Matrix metalloproteinases (MMPs), such as gelatinase A/MMP-2 and gelatinase B/MMP-9, are known to process the aminoterminal end of various chemokines, including interleukin-8 (IL-8/CXCL-8) and monocyte chemotactic protein-3 (MCP-3/CXCL-7). In the present study, two proteases, gelatinase B and neutrophil collagenase/MMP-8, are shown for the first time to process the carboxyterminal end of two chemokines, monokine induced by interferon (IFN)-gamma (MIG/CXCL-9) and IFN-inducible protein-10 (IP-10/CXCL-10). Neutrophil collagenase degrades MIG into small fragments and cleaves IP-10 behind positions 71 and 73. Gelatinase B degrades IP-10 and cleaves MIG at three different sites in its extended carboxyterminal region. This results in the formation of MIG(1-94), MIG(1-93), and MIG(1-90). In general, gelatinase B was more efficient than neutrophil collagenase in processing these chemokines. Alignment of the CXC chemokines with the respective cleavage sites by both MMPs identified the ELR motif as a possible determinant for amino terminal cleavage by these MMPs.
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PMID:Carboxyterminal cleavage of the chemokines MIG and IP-10 by gelatinase B and neutrophil collagenase. 1455 Feb 88


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