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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously demonstrated that vascular endothelial growth factor (VEGF)-elicited increase in the permeability of coronary venules was blocked by the nitric oxide (NO) synthase inhibitor NG-monomethyl-L-arginine (L-NMMA). The aim of this study was to delineate in more detail the signaling pathways upstream from NO production in VEGF-induced venular hyperpermeability. The apparent permeability coefficient of albumin (Pa) and endothelial cytosolic Ca2+ concentration ([Ca2+]i) were measured in intact perfused porcine coronary venules using fluorescence microscopy. VEGF (10(-10) M) induced a two- to threefold increase in Pa, which was blocked by a monoclonal antibody directed against the VEGF receptor Flk-1/KDR, the phospholipase C (PLC) antagonist U-73122, or the protein kinase C (PKC) antagonist bisindolylmaleimide (BIM). In 12 venules that displayed the [Ca2+]i response to bradykinin (10(-6) M) and ionomycin (10(-6) M), only 4 vessels responded to VEGF with a transient increase in [Ca2+]i. Furthermore, Western blot analysis of cultured human umbilical vein endothelial cells showed that VEGF increased tyrosine phosphorylation of PLC-gamma and serine phosphorylation of endothelial constitutive NO synthase (ecNOS). The hyperphosphorylation of PLC-gamma was greatly attenuated by the KDR receptor antibody and U-73122, but not by BIM or L-NMMA. In contrast, U-73122 and BIM were able to inhibit VEGF-elicited serine phosphorylation of ecNOS. The results suggest that VEGF induces venular hyperpermeability through a KDR receptor-mediated activation of PLC. In turn, ecNOS is activated by PLC-mediated PKC and/or cytosolic Ca2+ elevation stimulation.
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PMID:Role of phospholipase C, protein kinase C, and calcium in VEGF-induced venular hyperpermeability. 995 Aug 55

The melanocortin 1 receptor (MC1R), mast/stem cell growth factor receptor (KIT), and platelet-derived growth factor receptor alpha (PDGFRA) are loci that all belong to equine linkage group 2 (LG2). Of these, KIT was fluorescent in situ hybridization (FISH) mapped to ECA3q21 with equine cDNA and heterologous porcine BAC probes, while MC1R was localized to ECA3p12 and PDGFRA to ECA3q21 with heterologous porcine BAC probes. A three-step comparison between ECA3 and donkey chromosomes was carried out. First, microdissected ECA3 painting probe was used on donkey chromosomes, which showed disruption of the equine synteny. Next, human (HSA) Chromosomes (Chrs) 16q and 4 specific paints, known to be homologous to ECA3p and 3q, respectively, were applied to detect homologous chromosomal segment(s) in donkey. Finally, four genes (MC1R, ALB, PDGFRA, KIT) and two equine microsatellite markers (SGCV18 and SGCV33) located on ECA3 were FISH mapped to donkey chromosomes. The findings refined the cross species painting homology results and added six new markers to the nascent donkey gene map. The hypothesis that Tobiano coat color in horses may be associated with a chromosomal inversion involving genes within LG2 was tested by G-banding-based cytogenetic analysis and ordering of four loci-KIT, PDGFRA, albumin (ALB), and MC1R-in Tobiano and non-tobiano (homozygous as well as heterozygous) horses. However, no difference either in banding patterns or location/relative order of the genes was observed in the three classes. The study highlights successful FISH mapping of BAC probes across evolutionarily diverged species, viz., pig and horse/donkey, and represents the first use of large-sized individual clones across distantly related farm animals.
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PMID:Comparison of horse chromosome 3 with donkey and human chromosomes by cross-species painting and heterologous FISH mapping. 1005 24

Poly(lactic-co-glycolic)-D,L-85/15 (PLAGA) nanocapsules and poly(epsilon caprolactone) (PCL) nanocapsules were labeled with a relatively long half-life compound that is usually used in humans; that is, 111In-labelled oxine (111In oxine). This labeling technique led to a high 111In oxine entrapment efficiency and good stability during dialysis against phosphate buffer and phosphate buffered albumin solution. Because of these characteristics, the nanocapsules biodistribution was followed up after intravenous administration for up to 96 h by determining the gamma activity in the tissues after sampling. The administration of the PCL-encapsulated 111In oxine led to a decrease in the blood radioactivity and an increase in the liver radioactivity compared with the solution. This effect was even more pronounced with the PLAGA nanocapsules. Finally, the activity level in other tissues, such as the kidneys, the lungs, and the spleen, appeared to be rather low and only slightly affected by the encapsulation into one or the other polymer.
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PMID:Comparison of the biodistribution in mice of 111indium oxine encapsulated into poly(lactic-co-glycolic)-D,L-85/15 and poly(epsilon caprolactone) nanocapsules. 1018 56

This work evaluates the efficacy of the spray-drying technique to prepare poly(epsilon-caprolactone) (PCL) microparticles containing an entrapped model antigen (bovine albumin, BSA). The presence of a stabiliser was found to be an important parameter when preparing PCL microparticles containing a hydrophilic antigen. The effect of various technological parameters (concentration of the polymer and protein solutions, organic/aqueous phases ratio, nature of solvents and emulsion parameters such as duration and speed of agitation) on microparticle morphology and size, BSA entrapment and encapsulation efficiency was studied. Microparticles were characterized by a mean size from 9.56+/-0.25 to 24.31+/-2.87 microm and a BSA entrapment from 0.80+/-0.02 to 24.21+/-0.23% (w/w). SDS-PAGE electrophoresis and isoelectric focusing (IEF) confirmed the conservation of the physicochemical characteristics of the BSA entrapped within PCL microparticles produced by spray-drying. Together, these results showed that spray-drying is an efficient technique to overcome the key obstacle that represents the scaling-up of the manufacturing process to produce sufficient quantities of vaccine for clinical trials and, ultimately, commercialization.
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PMID:Influence of various technological parameters on the preparation of spray-dried poly(epsilon-caprolactone) microparticles containing a model antigen. 1089 88

Nanoparticles possessing poly(ethylene glycol) (PEG) chains on their surface have been described as blood persistent drug delivery system with potential applications for intravenous drug administration. Considering the importance of protein interactions with injected colloidal dug carriers with regard to their in vivo fate, we analysed plasma protein adsorption onto biodegradable PEG-coated poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA) and poly(varepsilon-caprolactone) (PCL) nanoparticles employing two-dimensional gel electrophoresis (2-D PAGE). A series of corona/core nanoparticles of sizes 160-270 nm were prepared from diblock PEG-PLA, PEG-PLGA and PEG-PCL and from PEG-PLA:PLA blends. The PEG Mw was varied from 2000-20000 g/mole and the particles were prepared using different PEG contents. It was thus possible to study the influence of the PEG corona thickness and density, as well as the influence of the nature of the core (PLA, PLGA or PCL), on the competitive plasma protein adsorption, zeta potential and particle uptake by polymorphonuclear (PMN) cells. 2-D PAGE studies showed that plasma protein adsorption on PEG-coated PLA nanospheres strongly depends on the PEG molecular weight (Mw) (i.e. PEG chain length at the particle surface) as well as on the PEG content in the particles (i.e. PEG chain density at the surface of the particles). Whatever the thickness or the density of the corona, the qualitative composition of the plasma protein adsorption patterns was very similar, showing that adsorption was governed by interaction with a PLA surface protected more or less by PEG chains. The main spots on the gels were albumin, fibrinogen, IgG, Ig light chains, and the apolipoproteins apoA-I and apoE. For particles made of PEG-PLA45K with different PEG Mw, a maximal reduction in protein adsorption was found for a PEG Mw of 5000 g/mole. For nanospheres differing in their PEG content from 0.5 to 20 wt %, a PEG content between 2 and 5 wt % was determined as a threshold value for optimal protein resistance. When increasing the PEG content in the nanoparticles above 5 wt % no further reduction in protein adsorption was achieved. Phagocytosis by PMN studied using chemiluminescence and zeta potential data agreed well with these findings: the same PEG surface density threshold was found to ensure simultaneously efficient steric stabilization and to avoid the uptake by PMN cells. Supposing all the PEG chains migrate to the surface, this would correspond to a distance of about 1.5 nm between two terminally attached PEG chains in the covering 'brush'. Particles from PEG5K-PLA45K, PEG5K-PLGA45K and PEG5K-PCL45K copolymers enabled to study the influence of the core on plasma protein adsorption, all other parameters (corona thickness and density) being kept constant. Adsorption patterns were in good qualitative agreement with each other. Only a few protein species were exclusively present just on one type of nanoparticle. However, the extent of proteins adsorbed differed in a large extent from one particle to another. In vivo studies could help elucidating the role of the type and amount of proteins adsorbed on the fate of the nanoparticles after intraveinous administration, as a function of the nature of their core. These results could be useful in the design of long circulating intravenously injectable biodegradable drug carriers endowed with protein resistant properties and low phagocytic uptake.
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PMID:'Stealth' corona-core nanoparticles surface modified by polyethylene glycol (PEG): influences of the corona (PEG chain length and surface density) and of the core composition on phagocytic uptake and plasma protein adsorption. 1091 52

The chelating and antioxidant effects of pyrrolidine dithiocarbamate (PDTC) have been investigated extensively for preventing cell death induced by different insults. However, the toxic effects of PDTC have been studied only recently and fewer studies on the toxic effects on astrocytes have been reported. In our study, we demonstrated that both PDTC and Cu(2+) alone were rated as only weakly toxic in inducing cell death in cortical astrocytes with IC(50) of 300 microM and 180 microM, respectively. However, PDTC and Cu(2+) in the complex form markedly potentiated with each other by about 1,000-fold with IC(50) of 0.3 microM PDTC plus 10 microM Cu(2+). Other metals at concentrations of 3-10 microM (VO(4)(5+), Cr(6+), Mn(2+), Fe(2+), Co(2+), Ni(2+), Zn(2+), Pb(2+), Bi(2+), Ba(2+), UO(2+), Cs(+), SeO(4)(2-), La(3+)) had no such potentiating effects on PDTC. Changes in morphology (nuclear condensation), apoptotic body formation, and hypodiploidity of DNA suggested that the PDTC-Cu(2+) complex induced cell death through an apoptotic process. Further studies showed that the PDTC-Cu(2+) complex decreased mitochondrial membrane potential, increased hydrogen peroxide production, and depleted GSH contents. After the increased oxidative stress, PDTC-Cu(2+) complex differentially activated JNKs, ERK, p38 and caspase 3, which caused PARP degradation in a time-dependent manner. All these effects were consistent with the increased cellular Cu contents. The nonpermeable copper-specific chelator bathocuproine disulfonate (BCPS), but not the permeable Cu(2+) chelator neocuproine, abolished all the observed effects. Antioxidants (N-acetylcysteine [NAC], vitamin C), catalase, and Cu(2+)-binding proteins (albumin, hemoglobin, and higher serum) reduced the cytotoxic effects of PDTC-Cu(2+) complex. We concluded that the death signaling pathway of PDTC-Cu(2+) complex was mediated by oxidative stress and subsequent JNK activation. These findings imply that PDTC, a widely used pesticide and medicine that is capable of penetrating the blood-brain barrier, may cause neurotoxicity through astrocyte dysfunction.
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PMID:Death signaling pathway induced by pyrrolidine dithiocarbamate-Cu(2+) complex in the cultured rat cortical astrocytes. 1094 Nov 51

Proliferation of vascular smooth muscle cells (VSMC) contributes to the pathogenesis of atherosclerosis, and glycated serum albumin (GSA, Amadori adduct of albumin) might be a mitogen for VSMC proliferation, which may further be associated with diabetic vascular complications. In this study, we investigated the involvement of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK), and protein kinase C (PKC), in GSA-stimulated mitogenesis, as well as the functional relationship between these factors. VSMC stimulation with GSA resulted in a marked activation of ERK. The MAPK kinase (MEK) inhibitor, PD98059, blocked GSA-stimulated MAPK activation and resulted in an inhibition of GSA-stimulated VSMC proliferation. GSA also increased PKC activity in VSMC in a dose-dependent manner. The inhibition of PKC by the PKC inhibitors, GF109203X and Rottlerin (PKCdelta specific inhibitor), as well as PKC downregulation by phorbol 12-myristate 13-acetate (PMA), inhibited GSA-induced cell proliferation and blocked ERK activation. This indicates that phorbol ester-sensitive PKC isoforms including PKCdelta are involved in MAPK activation. Thus, we show that the MAPK cascade is required for GSA-induced proliferation, and that phorbol ester-sensitive PKC isoforms contribute to cell activation and proliferation in GSA-stimulated VSMC.
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PMID:Glycated serum albumin-induced vascular smooth muscle cell proliferation through activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway by protein kinase C. 1123 43

We have previously shown that carboxymethyl dextran benzylamide (CMDB7), a heparin-like molecule, inhibits the growth of tumors xenografted in nude mice, angiogenesis, and metastasis by altering the binding of angiogenic growth factors, including platelet-derived growth factor, transforming growth factor beta, and fibroblast growth factor 2, to their specific receptors. In this study, we explore the effect of CMDB7 on the most specific angiogenic growth factor, vascular endothelial growth factor 165 (VEGF(165)). We demonstrate here that CMDB7 inhibits the mitogenic effect of VEGF(165) on human umbilical vein endothelial cells (HUV-ECs) by preventing the VEGF(165)-induced VEGF receptor-2 (KDR) autophosphorylation and consequently a specific intracellular signaling. In competition experiments, the binding of (125)I-VEGF(165) to HUV-ECs is inhibited by CMDB7 with an IC(50) of 2 microm. Accordingly, CMDB7 inhibits the cross-linking of (125)I-VEGF(165) to the surface of HUV-ECs, causing the disappearance of both labeled complexes, 170-180 and 240-250 kDa. We show that CMDB7 increases the electrophoretic mobility of VEGF(165), thus evidencing formation of a stable complex with this factor. Moreover, CMDB7 reduces the (125)I-VEGF(165) binding to coated heparin-albumin and prevents a heparin-induced increase in iodinated VEGF(165) binding to soluble (125)I-KDR-Fc chimera. Concerning KDR, CMDB7 has no effect on (125)I-KDR-Fc electrophoretic migration and does not affect labeled KDR-Fc binding to coated heparin-albumin. In the presence of VEGF(165), (125)I-KDR-Fc binding to heparin is enhanced, and under these conditions, CMDB7 interferes with KDR binding. These data indicate that CMDB7 effectively inhibits the VEGF(165) activities by interfering with heparin binding to VEGF(165) and VEGF(165).KDR complexes but not by direct interactions with KDR.
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PMID:Vascular endothelial growth factor 165 (VEGF(165)) activities are inhibited by carboxymethyl benzylamide dextran that competes for heparin binding to VEGF(165) and VEGF(165).KDR Complexes. 1151 38

Advanced glycation end products (AGEs) are generated during long term diabetes and are correlated with the development of diabetic complications, such as retinopathy. Diabetic retinopathy is characterized by an increased retinal neovascularization due to the action of the angiogenic factor, vascular endothelial growth factor (VEGF). In this report, we show that injection of insulin and glycated albumin (Alb-AGE) to mice increases VEGF mRNA expression in eyes. Insulin and Alb-AGE stimulate VEGF mRNA and protein expression in retinal epithelial cells (ARPE-19). Alb-AGE-induced VEGF expression is not modulated by the use of antioxidants, N-acetyl-l-cysteine or pyrrolidinedithiocarbamate, or by an inhibitor of phosphatidylinositol 3-kinase (PI3K), wortmannin. However, using an inhibitor of ERK activation, U0126, we show that Alb-AGE stimulates VEGF expression through an ERK-dependent pathway. Accordingly, we found that Alb-AGE activated mitogen-activate protein kinase, ERK1/2, JNK1/2, but not p38, and that Alb-AGE did not activate PI3K and PKB. Moreover, Alb-AGE activated the transcription factor, hypoxia inducible factor-1 (HIF-1) DNA binding activity. This activation is mediated by an increase in accumulation of the HIF-1alpha protein through an ERK-dependent pathway. Thus, stimulation of VEGF expression by Alb-AGE, through the activation of HIF-1, could play an important role in the development of diabetic retinopathy.
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PMID:Regulation of vascular endothelial growth factor expression by advanced glycation end products. 1157 Dec 95

The mechanism by which tumor necrosis factor alpha (TNFalpha) increases endothelial permeability is unclear. Vascular endothelial (VE) cadherin (cadherin 5) is an important contributor to endothelial monolayer integrity. The purpose of our study was to determine the effect of TNFalpha on VE-cadherin cell-surface expression and to identify the signaling pathways involved in TNF-induced changes in cadherin expression. Human umbilical vein endothelial cell monolayer permeability was measured by enzyme-linked immunosorbent assay for biotin-labeled albumin. Immunofluorescence, laser confocal microscopy, and Western immunobloting were used to assess VE cadherin distribution. Mitogen-activated protein kinase (MAPK) activity was determined using functional kinase assays and was inhibited with the compounds SB202190 and PD98059. TNFalpha significantly increased permeability and induced p38 and ERK MAPK activation compared with controls (P < 0.05). These changes were associated with a loss of membrane-associated VE cadherin. Inhibition of p38 but not ERK MAPK significantly reduced the effect of TNFalpha on endothelial permeability and cell-surface VE cadherin expression. p38 MAP kinase activation appears to be an important upstream signaling event associated with increased endothelial permeability and vascular endothelial cadherin redistribution.
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PMID:The role of p38 map kinase in tumor necrosis factor-induced redistribution of vascular endothelial cadherin and increased endothelial permeability. 1209 40


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