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)

Effect of new calcium antagonist m-nisoldipine (m-Nis) on MCT-induced PH in rats and its mechanisms were investigated. Rats were injected with a single dose (60 mg x kg(-1)) of MCT subcutaneously to induce PH. Pulmonary haemodynamic measurement and lung tissue morphological investigations were undertaken. The MDA production and SOD activity in the serum were tested. PCNA, ERK1 and p-ERK expressions were analyzed by Western blotting. The expressions of 5-HT and PCNA were observed with immunohistochemistry. Results suggested that the PAP, right ventricular index and the degree of muscularization of small pulmonary artery were elevated markedly in MCT group, which was attenuated by m-Nis treatment. A significant reduction in MDA production and an increase in the SOD activity in the serum were also observed in all three m-Nis groups. The number of PCNA and 5-HT positive smooth muscle cells increased significantly in MCT group, and m-Nis treatment attenuated the expression obviously. Western blotting results suggested that the protein expression of PCNA and the ratio of p-ERK/ ERK1 increased markedly in MCT group and decreased by m-Nis. In conclusion, m-Nis protected against MCT-induced PH by decreasing PAP, right ventricular index, PAMSCs proliferation and pulmonary artery remodelling, which may be related to the reduction of 5-HT and the suppression of the ERK/MAPK signal pathway.
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PMID:m-Nisoldipine attenuates monocrotaline-induced pulmonary hypertension by suppressing 5-HT/ERK MAPK pathway. 1912 64

Aldosterone (Aldo) stimulates glomerular mesangial cell (MC) proliferation, in part, through an ERK1/2-dependent pathway. In this study, we examined whether Aldo activation of ERK1/2 in MC is mediated through redox-dependent EGF receptor (EGFR) transactivation, as well as the involvement of other signaling mechanisms in Aldo-induced MC proliferation. Aldo increased human MC proliferation, as determined by [(3)H]thymidine incorporation and cell counts. This increase in proliferation was blocked by inhibition of the mineralocorticoid receptor (MR). Continuing our observations downstream in the signaling pathway, we examined the ability of Aldo to activate both the Ras/MAPK and the PI3K signaling pathways. Aldo increased Ki-RasA and Ki-RasA:GTP levels, and sequentially phosphorylated c-Raf, MAPK kinase (MEK1/2), and ERK1/2. Ki-RasA small interfering RNA (siRNA), the c-Raf inhibitor GW5074, and the MEK1/2 inhibitor PD98059 reduced Aldo-induced cell proliferation by approximately 65%. Aldo also increased phosphorylation of PI3K, Akt, the mammalian target of rapamycin (mTOR), and the 70-kDa ribosomal S6 kinase (p70S6K1). Inhibition of the PI3K pathways by the selective PI3K inhibitor LY 294002, an Akt inhibitor, or the mTOR inhibitor rapamycin reduced cell proliferation by 51%. Combining LY 294002 and PD98059 completely blocked Aldo-induced MC proliferation. Next, we confirmed that Aldo exerts its effect on MAPK and PI3K activation, as well as on cell proliferation, by activating the EGFR. Pretreatment with the EGFR antagonist AG1478 inhibited MC proliferation, as well as the activation of Ras/MAPK and PI3K/Akt, suggesting that Ras/MAPK and PI3K/Akt activation occur downstream of EGFR activation. Finally, we examined the role of reactive oxygen species (ROS) in Aldo-induced transactivation of the EGFR. Aldo-induced ROS were predominantly generated by mitochondria. Pretreatment with the antioxidant N-acetyl-l-cysteine, catalase, SOD, mitochondrial respiratory chain complex I inhibitor rotenone (Rot), NADPH oxidase inhibitor apocynin, and DPI significantly inhibited Aldo-stimulated MC proliferation as well as EGFR transactivation. However, Rot reduced MC proliferation more potently than apocynin and DPI. In conclusion, Aldo stimulated cell proliferation through MR-mediated, redox-sensitive EGFR transactivation, which was dependent on the Ki-RasA/c-Raf/MEK/ERK and PI3K/Akt/mTOR/p70S6K1 signaling pathways in human MCs.
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PMID:Aldosterone-induced mesangial cell proliferation is mediated by EGF receptor transactivation. 1933 32

The present study was undertaken to investigate whether chronic endurance exercise affects tau phosphorylation levels in the brain with Alzheimer's disease (AD)-like pathology. To address this, the transgenic (Tg) mouse model of tauopathies, Tg-NSE/htau23, which expresses human tau23 in the brain, was chosen. Animals were subjected to chronic exercise for 3 months from 16 months of age. The exercised Tg mouse groups were treadmill run at speeds of 12 m/min (intermediate exercise group) or 19 m/min (high exercise group) for 1 hr/day, 5 days/week, during the 3-month period. Chronic endurance exercise in Tg mice increased the expression of Cu/Zn-superoxide dismutase (SOD) and catalase, and also their enzymatic activities in the brain. In parallel, chronic exercise in Tg mice up-regulated the expression of phospho-PKCalpha, phospho-AKT, and phospho-PI3K, and down-regulated the expressions of phospho-PKA, phosphor-p38, phospho-JNK, and phospho-ERK. Moreover, chronic exercise up-regulated both cytosolic and nuclear levels of beta-catenin, and the expression of T-cell factor-4 (Tcf-4) and cyclin D1 in the brain. As a consequence of such changes, the levels of phospho-tau in the brain of Tg mice were markedly decreased after exercise. Immunohistochemical analysis showed an exercised-induced decrease of the phospho-tau levels in the CA3 subregion of the hippocampus. These results suggest that chronic endurance exercise may provide a therapeutic potential to alleviate the tau pathology.
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PMID:Repression of tau hyperphosphorylation by chronic endurance exercise in aged transgenic mouse model of tauopathies. 1936 Sep 3

To investigate the protective effects of penehyclidine hydrochloride (PHC) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the underlying molecular mechanism. ALI was induced by intravenous injection of LPS (5mg/kg). Male Sprague-Dawley (SD) rats challenged with or without LPS were pretreated with varied doses of PHC 0.5h before injection of LPS or saline. Blood gas in arterial blood, lung weight gain, bronchoalveolar lavage fluid (BALF), and neutrophils sequestration were examined 6h after administration of LPS. Pathological changes of lung tissue were measured by light microscopy. Phosphorylation of mitogen-activated protein kinase (MAPK) family and NF-kappaB were detected by western blot. All animals demonstrated drops in arterial oxygen tension (PaO(2)) after LPS application, which were significantly reversed by PHC pretreatment. Administration of PHC reduced lung water gain, bronchoalveolar lavage protein content, infiltration of neutrophils, malondialdehyde (MDA) content, and lactate dehydrogenase (LDH) activity and enhanced superoxide dismutase (SOD) activity. Histopathological study also indicated that PHC treatment markedly attenuated lung histopathological changes, alveolar hemorrhage, and inflammatory cells infiltration with evidence of decreasing of myeloperoxidase (MPO) activity. Furthermore, p38MAPK, ERK, and NF-kappaB were activated in 6h after LPS treatment, which could be blunted by PHC, while JNK remained unchanged. These findings confirmed significant protection by PHC against LPS-induced lung vascular leak and inflammation and implicated inhibition of p38MAPK activation signaling a potential role for PHC in the management of ALI.
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PMID:Penehyclidine hydrochloride attenuates LPS-induced acute lung injury involvement of NF-kappaB pathway. 1938 82

Constitutive ERK activation, superoxide dismutases (SOD) and p53 mutations are implicated in modulating tumor apoptotic response. We now investigated whether human melanoma survival in response to sodium nitroprusside (SNP) is modulated by: (a) stable introduction of a DN-mutant p53; (b) pharmacologically inhibiting ERK activation with UO126; (c) addition of exogenous SOD. Nitroprusside releases nitric oxide (NO) when intact, or acts in a NO-independent manner via iron and residual cyanide after light exposure (lex-SNP). When tested at 300 microM in 72 h treatments by cytometric live-dead assays, intact SNP caused a 50% lethality versus a 30% lethality induced by lex-SNP. No protection from SNP toxicity was seen when inhibiting the PI3-kinase pathway with LY294002 or c-Jun NH(2) kinase signaling with SP600125. However, pretreatment with UO126 protected from SNP-mediated cell death including counteracting apoptosis-associated Bax expression and PARP cleavage, plus reversing loss of Cu,Zn-SOD. Moreover, addition of exogenous SOD also protected cells from SNP toxicity. In spite of the greater earlier effects of intact SNP, cells treated with single doses of either intact or lex-SNP, revealed about a 90% mortality in longer 120 h treatments, and these were also counteracted by UO126 or exogenous SOD. This report is the first to show that: constitutive ERK activation characteristic of cancer cells, increases a nitroprusside-induced apoptosis modulated by SOD.
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PMID:ERK activation increases nitroprusside induced apoptosis in human melanoma cells irrespective of p53 status: role of superoxide dismutases. 1939 58

Neprilysin (NEP, neutral endopeptidase, EC3.4.24.11), a zinc metallopeptidase expressed on the surface of endothelial cells, influences vascular homeostasis primarily through regulated inactivation of natriuretic peptides and bradykinin. Earlier in vivo studies reporting on the anti-atherosclerotic effects of NEP inhibition and on the atheroprotective effects of flow-associated laminar shear stress (LSS) have lead us to hypothesize that the latter hemodynamic stimulus may serve to down-regulate NEP levels within the vascular endothelium. To address this hypothesis, we have undertaken an investigation of the effects of LSS on NEP expression in vitro in bovine aortic endothelial cells (BAECs), coupled with an examination of the signalling mechanism putatively mediating these effects. BAECs were exposed to physiological levels of LSS (10 dynes/cm(2), 24h) and harvested for analysis of NEP expression using real-time PCR, Western blotting, and immunocytochemistry. Relative to unsheared controls, NEP mRNA and protein were substantially down-regulated by LSS (>or=50%), events which could be prevented by treatment of BAECs with either N-acetylcysteine, superoxide dismutase, or catalase, implicating reactive oxygen species (ROS) involvement. Employing pharmacological and molecular inhibition strategies, the signal transduction pathway mediating shear-dependent NEP suppression was also examined, and roles implicated for G beta gamma, Rac1, and NADPH oxidase activation in these events. Treatment of static BAECs with angiotensin-II, a potent stimulus for NADPH oxidase activation, mimicked the suppressive effects of shear on NEP expression, further supporting a role for NADPH oxidase-dependent ROS production. Interestingly, inhibition of receptor tyrosine kinase signalling had no effect. In conclusion, we confirm for the first time that NEP expression is down-regulated in vascular endothelial cells by physiological laminar shear, possibly via a mechanotransduction mechanism involving NADPH oxidase-induced ROS production.
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PMID:Down-regulation of neprilysin (EC3.4.24.11) expression in vascular endothelial cells by laminar shear stress involves NADPH oxidase-dependent ROS production. 1946 87

In this study, the potentially harmful effect of the exposure to fumed and porous silicon dioxide (silica) nanoparticles was investigated using human bronchial epithelial cell, Beas-2B, with a focus on the involvement of oxidative stress as the toxic mechanism. Silica nanoparticles-induced oxidative stress was assessed by examining the formation of reactive oxygen species (ROS) and induction of antioxidant enzymes, such as superoxide dismutase (SOD) and heme oxygenase-1 (HO-1). Subsequently, to understand the mechanism of nanoparticles-induced oxidative stress, the involvement of oxidative stress-responding transcription factors, such as, nuclear factor-kappaB (NF-kappaB) and nuclear factor-E2-related factor-2 (Nrf-2), as well as the mitogen-activated protein (MAP) kinase signal transduction pathway were investigated. From the overall results, silica nanoparticles exerted toxicity via oxidative stress, which lead to the induction of HO-1 via the Nrf-2-ERK MAP kinase signaling pathway; cells exposed to porous silica nanoparticles showed a more sensitive response than those exposed to fumed silica. Nevertheless, the parameters tested were rather limited in terms of gaining a full understanding of the oxidative stress and cellular response due to exposure to silica nanoparticles. Further studies on the mechanism by which silica nanoparticles induce the Nrf-2-ERK MAP kinase pathway, to more clearly elucidate the silica-induced oxidative stress, as well as on the relationship between the physico-chemical properties of nanoparticles and their cytotoxicity are warranted to gain an understanding of the phenomenon of different sensitivities between porous and fumed silica.
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PMID:Oxidative stress of silica nanoparticles in human bronchial epithelial cell, Beas-2B. 1960 32

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder characterized by selective loss of motor neurons (MNs). Twenty percent of familial ALS cases are associated with mutations in Cu(2+)/Zn(2+) superoxide dismutase (SOD1). To specifically understand the cellular mechanisms underlying mutant SOD1 toxicity, we have established an in vitro model of ALS using rat primary MN cultures transfected with an adenoviral vector encoding a mutant SOD1, G93A-SOD1. Transfected cells undergo axonal degeneration and alterations in biochemical responses characteristic of cell death such as activation of caspase-3. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can increase axonal outgrowth, block neuronal apoptosis, and promote neurogenesis. Decreased VEGF gene expression in mice results in a phenotype similar to that seen in patients with ALS, thus linking loss of VEGF to the pathogenesis of MN degeneration. Decreased neurotrophic signals prior to and during disease progression may increase MN susceptibility to mutant SOD1-induced toxicity. In this study, we demonstrate a decrease in VEGF and VEGFR2 levels in the spinal cord of G93A-SOD1 ALS mice. Furthermore, in isolated MN cultures, VEGF alleviates the effects of G93A-SOD1 toxicity and neuroprotection involves phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling. Overall, these studies validate the usefulness of VEGF as a potential therapeutic factor for the treatment of ALS and give valuable insight into the responsible signaling pathways and mechanisms involved.
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PMID:Vascular endothelial growth factor prevents G93A-SOD1-induced motor neuron degeneration. 1967 55

Mast cells are immune effector cells that are involved in allergies and inflammation through the release of mediators such as histamine, PGs, and cytokines. Uncoupling protein 2 (UCP2) is a mitochondrial protein that inhibits insulin secretion from beta cells, possibly through down-regulation of reactive oxygen species production. We hypothesized that UCP2 could also regulate mast cell activation. In this study, we show that mouse bone marrow mast cells (BMMCs) and human leukemic LAD2 mast cells express UCP2. BMMCs from Ucp2(-/-) mice exhibited greater histamine release, whereas overexpression of UCP2 in LAD2 cells reduced histamine release after both allergic and nonallergic triggers. Ucp2(-/-) BMMCs also had elevated histamine content and histidine decarboxylase expression. Histamine content was reduced by overexpression of UCP2 or treatment with the mitochondrial-targeted superoxide dismutase-mimetic (TBAP) tetrakis(4-benzoic acid) porphyrin manganese(III). Furthermore, Ucp2(-/-) BMMCs also had greater production of both IL-6 and PGD(2) as well as ERK phosphorylation, which is known to regulate PG synthesis. Intradermal administration of substance P, an activator of skin mast cells, and challenge with DNP-human serum albumin after passive sensitization induced significantly greater vascular permeability in the skin of Ucp2(-/-) mice in vivo. Our results suggest that UCP2 can regulate mast cell activation.
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PMID:Mitochondrial uncoupling protein 2 inhibits mast cell activation and reduces histamine content. 1984 69

2-Methoxyestradiol (2ME2) is a normal physiological metabolite of 17beta-estradiol with anti-proliferative and anti-angiogenic activities. The purpose of this study is to elucidate the mechanism whereby 2ME2 induces endoreduplication of the well-differentiated nasopharyngeal carcinoma (NPC) cells. We report here that 2ME2 induces G2/M phase cell cycle arrest followed by endoreduplication of the well-differentiated HK-1 cells. The increase in chromosome number was confirmed by cytogenetic study. Analysis of stress signaling pathways revealed the phosphorylation activation of ERK, JNK and p38 MAPKs at various times after 2ME2 treatment. Pre-treatment of 2ME2-treated HK-1 cells with JNK inhibitor (SP600125), ERK inhibitor (PD98059) and p38 MAPK inhibitor (SB203580) resulted in the reduction of endoreduplicating cells. Furthermore, the increase in the phosphorylation of JNK was accompanied by an increase in the reactive oxygen species. In addition, endoreduplication was observed in cells after treatment with superoxide donor, 2,3-dimethoxy-1,4-naphoquinone (DMNQ). Confocal microscopic analysis also revealed the increase in mitochondrial superoxide anion in 2ME2-treated HK-1 cells. Pre-treatment of HK-1 cells with superoxide dismutase mimetic 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or overexpressing the mitochondrial enzyme MnSOD resulted in the reduction of phosphorylation of JNK and the formation of endoreduplicating cells. Furthermore, the tubulin filaments in cytoplasm remain intact in 2ME2-treated HK-1 cells after pre-treatment of TEMPO. Our results suggest that 2ME2 induces endoreduplication through the induction of oxidative stress and the activation of MAPK signal pathways. The biological significance of drug-induced endoreduplication will also be discussed.
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PMID:2-Methoxyestradiol induces endoreduplication through the induction of mitochondrial oxidative stress and the activation of MAPK signaling pathways. 1988 29


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