Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.25.1 (proteasome)
28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IL-8 is an important mediator of leukocyte trafficking and activation, participating in tumor angiogenesis, inflammatory processes and coronary atherosclerosis. Under flow conditions IL-8, in conjunction with MCP-1, triggers the firm adhesion of monocytes to the vascular endothelium. While previous studies have suggested the requirement of NF-kappaB for IL-8 secretion by endothelial cells, we investigated the possibility of IL-8 transactivation under conditions of NF-kappaB suppression. Inhibition of the proteasome by MG-132 or lactacystin completely blocked TNF-alpha-induced IkappaBalpha degradation as well as NF-kappaB activity in human arterial endothelial cells. Surprisingly, basal secretion of IL-8 protein was eight- to tenfold induced by proteasome inhibitors, while MCP-1 expression was, as expected, completely down-regulated. IL-8 was up-regulated at the transcriptional level, and promoter studies proved a more than ninefold induction of transcription factor AP-1 activity to be the cause of increased IL-8 transcription. Mutation of the AP-1 binding site in an IL-8 promoter construct completely abrogated this effect, while mutation of the NF-kappaB motif did not influence IL-8 transactivation by proteasome inhibitors. With DNA binding assays we found a seven- to eightfold induction of phosphorylated c-Jun and hence JNK kinase activity under MG-132 treatment. Induction of JNK kinase appeared independent of the cell type, even in tumor cell lines not responding to proteasome inhibitors. Since neither inactivation of p53 in wild-type p53 cells nor reintroduction of functional p53 into p53(-/-) cells affected MG-132-inducible IL-8 secretion, a direct influence of p53 on IL-8 regulation could be excluded. These results show that proteasome inhibitors can not only lead to functional AP-1 induction by enhanced c-Jun phosphorylation, but also transactivate the IL-8 gene in human endothelial cells despite complete suppression of NF-kappaB activity.
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PMID:Proteasome inhibition leads to NF-kappaB-independent IL-8 transactivation in human endothelial cells through induction of AP-1. 1220 33

The levels of platelet-derived microparticles (PDMPs), platelet activation markers (P-selectin, CD63, and PAC-1 on activated platelets), and C-C chemokines (monocyte chemotactic peptide [MCP]-1 and regulated on activation normally T-cell expressed and secreted [RANTES] were measured and compared in patients with acute myocardial infarction (AMI) or stable pectoris angina. These substances are thought to paricipate in the development of complications in patients with AMI. The percentage binding of anti-P-selectin, CD63, and PAC-1 antibody to platelets, and the levels of PDMPs (per 10(4) platelets) were higher in the patients with AMI than in those with stable pectoris angina (P-selectin, 23.1% +/- 2.1% vs. 10.3% +/- 1.2%, p < 0.001; CD63, 24.6% +/- 3.3% vs. 11.2% +/- 3.1%, p < 0.01; PAC-1, 14.1% +/- 1.7% vs. 9.3% +/- 2.1%, p < 0.05; PDMPs, 613 +/- 71 vs. 413 +/- 55, p < 0.01). There were no differences in platelet levels of GPIIb/IIIa and GPIb between groups. Levels of MCP-1 and RANTES were higher in the patients with AMI than in patients with stable pectoris angina (MCP-1, 430 +/- 35 vs. 265 +/- 23, p<0.01; RANTES, 175 +/- 32 vs. 88 +/- 29, p<0.001). The effects of percutaneous transluminal coronary angioplasty (PTCA) on the levels of these agents in patients with AMI were studied. Platelet activation markers were significantly decreased in patients with AMI after PTCA. RANTES level was also significantly decreased after treatment, but MCP-1 level was not changed. In addition, this tendency was clearer in STENT patients. These findings suggest that in patients with AMI PTCA, particularly STENT, may prevent the development of complications in which activated platelet and RANTES participate.
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PMID:Association of platelet-derived microparticles with C-C chemokines on vascular complication in patients with acute myocardial infarction. 1236 Dec 7

Expression of several cytokines involved in signal transduction such as TGFbeta-1 and the inflammatory chemokines including MCP-1 is elevated during the course of AIDS progression. The enhancement of these cellular proteins in astrocytic cells is mediated, at least in part, by HIV-1 Tat protein. Here, we investigate the possible regulation of MCP-1 transcription by Tat and the Smad family of transcription factors whose activities are induced by the TGFbeta-1 pathway. Results from transfection studies revealed that Smad-3 stimulates basal and Tat-mediated transcription of MCP-1 in human astrocytic cells. Smad-4, on the other hand, had no effect on the basal activity of the MCP-1 promoter, but showed the ability to decrease both Smad-3 and Tat-induced transcription of the MCP promoter. Results from protein-binding studies revealed the ability of both Smad-3 and Smad-4 to associate with the region of Tat spanning residues 1-40. Examination of the transcriptional activity of the various domains of Smad including MH1, at the N-terminus, and MH2, at the C-terminus of the protein indicated that neither MH1 or MH2 alone positively cooperate with Tat in modulating MCP-1 transcription. However, ectopic expression of MH1 and, more notably, MH2 severely suppressed transcriptional activation of MCP-1 by Tat in astrocytic cells. Binding studies revealed that similar to the full-length Smad protein, both MH1 and MH2 associate with Tat protein and that the residues between 1 and 40 of Tat are important for their interaction. These observations reveal a novel mechanism for Tat-mediated transcriptional activation via TGFbeta signaling pathway and provide evidence for regulation of MCP-1 gene transcription by this signaling pathway in human astrocytic cells.
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PMID:Regulation of MCP-1 gene transcription by Smads and HIV-1 Tat in human glial cells. 1275 67

Homocystinemia has been identified as an independent risk factor for atherosclerosis. Monocyte chemoattractant protein-l (MCP-l) is a potent chemokine that stimulates the migration of monocytes into the intima of the arterial wall. The authors investigated the role of intracellular redox status in the expression of MCP-l stimulated by homocysteine in endothelial cells. Homocysteine stimulated MCP-1 mRNA expression and protein production in a time-dependent and dose-dependent manner in endothelial cells, decreased intracellular glutathione (GSH) and protein thiol levels, as well as G6PDH activity and NADPH levels. Thiol reduced reagents, GSH, and dithiothreitol levels, and reversed the MCP-l mRNA expression and protein production in endothelial cells; in addition, thiol oxidized reagent, diamide, and BSO levels, and markedly potentiated homocysteine-mediated up-regulation of MCP-l mRNA expression and protein production in endothelial cells. These results demonstrate that homocysteine can trigger overexpression of the MCP-1 gene by altering the intracellular redox status, suggesting that the homocysteine-induced changes in the intracellular redox status play an important role in modulating the expression of MCP-l in endothelial cells.
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PMID:Intracellular redox status modulates monocyte chemoattractant protein-1 expression stimulated by homocysteine in endothelial cells. 1288 31

We previously reported that pyrrolidine dithiocarbamate blocked nuclear factor-kappaB (NF-kappaB) activation and attenuated interstitial inflammation and tubulointerstitial fibrosis in the rat obstructive nephropathy. Since pyrrolidine dithiocarbamate is an anti-oxidant and possesses additional biological properties, present experiment was conducted to clarify further the role of NF-kappaB in the development of tubulointerstitial fibrosis in obstructed kidney using a proteasome inhibitor that blocks NF-kappaB through stabilizing IkappaB, an endogenous inhibitor of NF-kappaB. At 5 days following unilateral ureteral obstruction (UUO) in rats, obstructed kidney exhibited tubulointerstitial fibrosis that was associated with macrophage infiltration. UUO decreased renal cortical IkappaB protein contents with concomitant increases in NF-kappaB DNA-binding activity and gene expression of monocyte chemoattractant protein-1. Administration of PSI, N-benzyloxy-carbonyl-Ile-Glu (O-t-Bu)-Ala-leucinal, a proteasome inhibitor, (3 mg/kg/day, s.c., b.i.d) to UUO rats inhibited proteasome activity and attenuated the changes in IkappaB content, NF-kappaB activity and MCP-1 mRNA expression observed in UUO rats. PSI also decreased macrophage influx and attenuated the development of fibrosis. Furthermore, up-regulated gene expression of pro-fibrogenic molecules observed in the obstructed kidney was attenuated by PSI. These results further support the notion that NF-kappaB plays an important role in the development of renal fibrosis in the obstructive nephropathy.
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PMID:Attenuation of renal fibrosis by proteasome inhibition in rat obstructive nephropathy: possible role of nuclear factor kappaB. 1296 39

Islet allografts are subject to rapid rejection through host cellular immune responses involving mononuclear cell recruitment and tissue injury. Interruption of leukocyte recruitment through chemokine receptor targeting is of therapeutic benefit in various experimental models, but little is known about the contribution of chemokine pathways to islet allograft rejection. We found that murine islets produce monocyte chemoattractant protein-1 (MCP-1; CCL2) in vitro and that islet allograft rejection was associated with intragraft expression of MCP-1 and its receptor, CCR2. We therefore investigated whether MCP-1 and CCR2 are required for the rejection of fully MHC-disparate islet allografts. Wild-type mice treated with blocking anti-MCP-1 mAb plus a brief, subtherapeutic course of rapamycin had long-term islet allograft survival, in contrast to the effect of treatment with either mAb or rapamycin alone. CCR2(-/-) mice treated with rapamycin also maintained islet allografts long-term. Both MCP/CCR2- and rapamycin-sensitive signals were required for maximal proliferation of alloreactive T cells, suggesting that MCP-1/CCR2 induce rejection by promoting alloreactive T cell clonal expansion and homing and migration. Prolonged islet allograft survival achieved by blockade of the MCP-1/CCR2 pathway plus rapamycin therapy was accompanied by a mononuclear cell infiltrate expressing the inhibitory receptor, programmed death-1 (PD-1), and its ligand (PD-L1, B7-H1), and prolongation of islet allograft survival was abrogated by anti-PD-L1 mAb therapy. These data show that the blockade of MCP-1 binding to CCR2 in conjunction with subtherapeutic immunosuppression can have profound effects on islet allograft survival and implicate the expression of the PD-1/PD-L1 pathway in the regulation of physiologic responses in vivo.
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PMID:Blocking the monocyte chemoattractant protein-1/CCR2 chemokine pathway induces permanent survival of islet allografts through a programmed death-1 ligand-1-dependent mechanism. 1466

Estrogen contributes to the development of breast cancer through mechanisms that are not completely understood. Estrogen influences the function of immune effector cells, primarily through alterations in cytokine expression. Chemokines are proinflammatory cytokines that attract various immune cells to the site of tissue injury or inflammation, and activate many cell types, including T lymphocytes and monocytes. As an initial step toward ultimately determining whether regulation of chemokine expression and/or biological activity by estrogen could potentially be a contributing factor to the development and progression of mammary tumors, we evaluated the effect of estrogen on the expression of specific chemokines in murine mammary tissue. We also evaluated whether exposure of female mice to various chemokines could alter the growth of mammary tumors in the presence of estrogen. We report here that estrogen significantly decreases levels of the chemokines MIP-1alpha and MCP-1/JE in murine mammary tissue. Co-treatment with 4-hydroxytamoxifen partially reverses the suppressive effect of estrogen on MIP-1alpha levels. Estrogen increases the growth of CCL- 51 cell-based tumors in the mammary glands of female mice. Co-treatment with the chemokine MIP-1alpha or MCP- 1/JE substantially decreases the ability of estrogen to stimulate the formation of CCL-51 cell-based tumors. Our results show that estrogen might influence the bioactivity of specific chemokines through alteration of chemokine expression in mammary tissue, and further suggest that decreases in murine chemokines evoked by estrogen exposure could contribute to the promotion of mammary tumor growth.
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PMID:Estrogen decreases chemokine levels in murine mammary tissue: implications for the regulatory role of MIP-1 alpha and MCP-1/JE in mammary tumor formation. 1466 21

Small volumes of cervical secretions have limited measurements of immunity at the cervix, which may be important to studies of human papillomavirus (HPV). We report the use of recycling immunoaffinity chromatography to efficiently study immune profiles in cervical secretions. Frozen pairs of plasma and cervical secretions (collected on ophthalmic sponges) were selected randomly from women with normal cervical cytology (n = 50) participating in a natural history study of HPV in Guanacaste, Costa Rica. Single 25- micro l aliquots of plasma and (diluted) cervical secretions were assayed for interleukin (IL) -1 beta, -2, -4, -6, -8, -10, -12, -13, -15, IFN-alpha, -beta, -gamma, tumor necrosis factor-alpha, -beta, RANTES (regulated on activation normal T-cell express and secreted), MCP-1 (monocyte chemoattractant protein), -2, -3, macrophage inflammatory protein-1 alpha, -1 beta (regulated on activation normal T-cell express and secreted), macrophage colony-stimulating factor, IgG, IgA, and cyclooxygenase 2. All of the specimens were tested as blind replicates, and refrozen plasma was retested 4 months later. To evaluate the reproducibility of the repeat measurements and to examine the correlation between plasma and cervical secretions, we calculated kappa values with 95% confidence intervals among categorized analyte values and Spearman correlation coefficients (rho) among detectable, continuous analyte values. Measurements of all of the analytes in either plasma or cervical secretions were highly reproducible, with all of the kappa > or = 0.78 (70% above 0.90), and all of the rho > or = 0.88 (96% above 0.90). Only IL-1 beta (kappa = 0.60 and rho = 0.82) and IL-6 (kappa = 0.50 and rho = 0.78) levels were strongly correlated between plasma and cervical secretions. IFN-gamma, tumor necrosis factor-beta, RANTES, MCP-1, MCP -2, macrophage inflammatory protein-1 alpha, and macrophage colony-stimulating factor levels were especially poorly correlated between plasma and cervical secretions (kappa < or = 0.25 and rho < or = 0.25). We conclude that recycling immunoaffinity chromatography is a reproducible method of measuring immune profiles from biological specimens, and immune profiles are not well correlated between plasma and cervical secretions, perhaps necessitating cervical collections to study cervix-specific immunity in HPV natural history studies.
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PMID:Immune profiling of plasma and cervical secretions using recycling immunoaffinity chromatography. 1469 36

Angiotensin II (Ang II) is implicated in the proinflammatory process in various disease situations. Thus, we sought to determine the role of Ang II in early inflammation-induced fibrosis of pressure-overloaded (PO) hearts. PO was induced by suprarenal aortic constriction (AC) at day 0 in male Wistar rats, and they were orally administered 0.1 mg/kg per day candesartan every day from day -7. This was the maximum dose of candesartan that did not change arterial pressure in hypertensive rats with AC (AC rats). In AC rats, cardiac angiotensin-converting enzyme (ACE) activity was transiently enhanced after day 1 and peaked at day 3, declining to lower levels by day 14, whereas serum ACE activity was not changed. In AC rats, PO induced early fibroinflammatory changes (monocyte chemoattractant factor [MCP]-1 and transforming growth factor [TGF]-beta expression, perivascular macrophage accumulation, and fibroblast proliferation), and thereafter, left ventricular hypertrophy developed, featuring myocyte hypertrophy, intramyocardial arterial wall thickening, and perivascular and interstitial fibroses. Candesartan suppressed the induction of MCP-1 and TGF-beta and reduced macrophage accumulation and fibroblast proliferation in PO hearts. Candesartan significantly prevented perivascular and interstitial fibrosis. However, candesartan did not affect myocyte hypertrophy and arterial wall thickening. In conclusion, a subdepressor dose of candesartan prevented the MCP-1-mediated inflammatory process and reactive myocardial fibrosis in PO hearts. Ang II might play a key role in reactive fibrosis in hypertensive hearts, independent of arterial pressure changes.
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PMID:Pressure-independent effects of angiotensin II on hypertensive myocardial fibrosis. 1469

Intracerebral infection with Theiler's virus induces a demyelinating disease that resembles human MS. In order to delineate the early events in virus-induced inflammatory disease, we have analyzed chemokine gene activation following Theiler's murine encephalomyelitis virus (TMEV) infection. Infection of primary astrocyte cultures results in activation of various chemokine genes (GRO-1, MCP-1, MCP-5, MIP-1alpha, MIP-1beta, MIP-2, RANTES, IP-10 and MCP-3) that are important in the initiation of an inflammatory response. As early as 1-3 h after TMEV infection, chemokine gene expression is strongly activated. In addition, proinflammatory cytokines do not interfere with TMEV-induced chemokine gene expression and some cytokines may function synergistically for virus-induced upregulation of chemokine gene expression. Chemokine gene activation by TMEV appears to be largely independent of the IFNalphabeta pathway and partly dependent on dsRNA-dependent protein kinase (PKR) and MAP kinase pathways. However, TMEV-induced chemokine gene expression is completely dependent on the NFkappaB pathway. These results strongly suggest that the expression of select chemokine genes upon TMEV infection is activated via the NFkappaB pathway, similar to that of proinflammatory cytokine genes, and these cellular gene products appear to synergistically promote inflammatory responses in the CNS.
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PMID:The scope and activation mechanisms of chemokine gene expression in primary astrocytes following infection with Theiler's virus. 1502 72


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