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)

Hyperglycemia is considered a primary cause of diabetic vascular complications. A hallmark of vascular disease is endothelial cell dysfunction characterized by diminished nitric-oxide (NO)-dependent phenomena such as vasodilation, angiogenesis, and vascular maintenance. This study was designed to investigate the effects of a high level of D-glucose on endothelial NO response, oxidative stress, and glucose metabolism. Bovine aortic endothelial cells (BAECs) were pretreated with a high concentration of glucose (HG) (22 mmol/L) for at least 2 weeks and compared with control cells exposed to 5 mmol/L glucose (NG). The effect of chronic hyperglycemia on endothelial NO-synthase (eNOS) activity and expression, glycogen synthase (GS) activity, extracellular-signal-regulated kinase (ERK 1,2), p38, Akt expression, and Cu/Zn superoxide-dismutse (SOD-1) activity and expression were determined. Western blot analysis showed that eNOS protein expression decreased in HG cells and was accompanied by diminished eNOS activity. The activity of GS was also significantly lower in the HG cells than in NG cells, 25.0+/-17.4 and 89+/-22.5 nmol UDP-glucose.mg protein(-1)x min(-1), respectively. Western blot analysis revealed a 40-60% decrease in ERK 1,2 and p38 protein levels, small modification of phosphorylated Akt expression, and a 30% increase in SOD-1 protein expression in HG cells. Although SOD expression was increased, no change was observed in SOD activity. These results support the findings that vascular dysfunction due to exposure to pathologically high D-glucose concentrations may be caused by impairment of the NO pathway and increased oxidative stress accompanied by altered glucose metabolism.
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PMID:Hyperglycemia reduces nitric oxide synthase and glycogen synthase activity in endothelial cells. 1238 15

We investigated the effects of high concentrations of glucose on plasminogen activator inhibitor-1 (PAI-1) gene expression in cultured rat vascular smooth muscle cells (VSMC). In response to a high glucose concentration (27.5 mM), PAI-1 mRNA increased within 2 h, peaked at 4 h, remained elevated for another 4 h, then decreased to basal levels at 24 h. On the other hand, mannose at the same concentration (22.5 mM mannose plus 5.5 mM glucose) as an osmotic control had little effect on PAI-1 mRNA expression. The expression of PAI-1 mRNA that was also increased by H(2)O(2), angiotensin II, or phorbol myristate acetate, was reversed by the MAPK kinase (MEK) inhibitor PD98059 or the specific protein kinase C (PKC) inhibitor GF109203X. High glucose appeared to activate MAPK and PKC in VSMC judging from Elk-1 and AP-1 activation, respectively. PD98059 inhibited and GF109203X prevented subsequent PAI-1 induction by glucose. These results suggest that glucose at high concentrations induces PAI-1 gene expression in VSMC at least partially via MAPK and PKC activation. This direct effect of glucose might have important implications for the increased plasma concentrations of PAI-1 and possibly atherosclerosis that are associated with diabetes.
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PMID:Glucose upregulates plasminogen activator inhibitor-1 gene expression in vascular smooth muscle cells. 1240 45

The yeast Saccharomyces cerevisiae has four genes, MCK1, MDS1 (RIM11), MRK1, and YOL128c, that encode homologues of mammalian glycogen synthase kinase 3 (GSK-3). A gsk-3 null mutant in which these four genes are disrupted showed growth defects on galactose medium. We isolated several multicopy suppressors of this growth defect. Two of them encoded Msn2p and phosphoglucomutase (PGM). Msn2p is a transcription factor that binds to the stress-response element (STRE). PGM is an enzyme that interconverts glucose-1 phosphate and glucose-6 phosphate and is regulated by Msn2p at the transcriptional level. Expression of the mRNAs of PGM2 and DDR2, whose promoter regions possess STRE sequences, on induction by heat shock or salt stress was reduced not only in an msn2 msn4 (msn2 homologue) double mutant but also in the gsk-3 null mutant. STRE-dependent transcription was greatly inhibited in the gsk-3 null mutant or mck1 mds1 double mutant, and this phenotype was suppressed by the expression of Mck1p but not of a kinase-inactive form of Mck1p. Although Msn2p accumulated in the nucleus of the gsk-3 null mutant as well as in the wild-type strain under various stress conditions, its STRE-binding activity was reduced in extracts prepared from the gsk-3 null mutant or mck1 mds1 double mutant. These results suggest that yeast GSK-3 promotes formation of a complex between Msn2p and DNA, which is required for the proper response to different forms of stress. Because neither Msn2p-GSK-3 complex formation nor GSK-3-dependent phosphorylation of Msn2p could be detected, the regulation of Msn2p by GSK-3 may be indirect.
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PMID:Yeast glycogen synthase kinase-3 activates Msn2p-dependent transcription of stress responsive genes. 1252 45

Based on the reported gene sequences, the segments containing 2-keto aldose reductase (2-KRA and B) genes were amplified by PCR from the plasmids and Erwinia sp. SCB125 each for gene expression and gene knocking out. Then cloning them into expression vector pBL and successfully expressing them with high enzyme activity in E. coli DH5 alpha. After their enzyme activities were proved, the work on gene knock out followed. Introducing the knock-out vector which distribute unstably during the cell division to the host strains Erwinia sp. SCB125. Screening firstly by the positive marker, one resistance which resulted from the expression of the resistance gene inserting inside the reductase genes and the negative marker, another resistance which outside the reductase genes in the vector. The strains selected out will be tested by further study. This work was the bases of blocking the pathway metabolism and constructing a recombinant strain that can produce 2-KLG directly from D-glucose by one-step fermentation.
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PMID:[Studies on gene knocking out of 2-keto aldose reductases from Erwinia sp. SCB125]. 1254 57

Two different 2,5-DKG reductases was purified from Corynebacterium sp. SCB3058, then its genomic DNA was used as template, a segment containing 2,5-DKG reductase I was amplified by PCR and cloned into pGEM3zf(+) to obtain the recombinant plasmid pGEM813. The sequence analysis showed that the cloned segment was 1107 bp in length, contained a single open reading frame of 834 nucleotides, which encoded a 34 kD protein consisted of 278 amino acids. After the primary control sequence was deleted, the expression vector pBL4 was constructed by plasmid pBL. With induction of temperature, a 34 kD protein was specifically expressed in E. coli DH5 alpha in high level. The expressed recombinant protein accounted for 20% of the total cell protein and had high specific enzyme activity. In spite of 30 degrees C, 37 degrees C or 42 degrees C induction, the specific activity of enzyme was almost the same level. These results indicate that most of the recombinant protein induced at 42 degrees C was existed with inclusion bodies. This work was the bases of constructing a recombinant Erwinia which can produce 2-KLG directly from D-glucose by one-step fermentation.
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PMID:[Cloning and expression in E. coli of 2,5-DKG reductase I from Corynebacterium]. 1254 22

We previously demonstrated that left ventricular hypertrophy (LVH) induced by angiotensin II infusion requires epidermal growth factor receptor (EGFR) activation to mediate the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway. To test whether the EGFR-mediated MAPK/ERK activation plays an important role in development and maintenance of LVH in spontaneously hypertensive rats (SHR), we investigated the effects of antisense oligodeoxynucleotide to EGFR (EGFR-AS) on LVH and blood pressure in young and adult SHR. EGFR-AS, sense oligonucleotide to EGFR (EGFR-S; 1.5 mg/kg), or vehicle control (5% dextrose) with liposome was injected once a week for 2 months in 5- or 13-week-old SHR. The effect of EGFR-AS on the expression of EGFR and phosphorylated ERK in the heart were examined by Western blots. After treatment, EGFR-AS significantly (P<0.05) decreased left ventricular weight/body weight and blood pressure in young SHR compared with EGFR-S or control-treated rats. In adult SHR, EGFR-AS did not affect left ventricular weight/body weight and blood pressure. EGFR and phosphorylated ERK significantly declined from 5 to 20 weeks (P<0.05). EGFR-AS, but not EGFR-S, significantly (P<0.05) decreased the expression of EGFR and phosphorylated ERK in young SHR, but had no significant effect in adult SHR. These results suggests that EGFR-mediated ERK activation is critically important for LVH in young SHR. This may be related to the high levels of EGFR and phosphorylated ERK in young SHR, suggesting a critical role of the EGFR-activated ERK pathway in cardiovascular development but not in the maintenance of established LVH in adult SHR.
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PMID:Antisense to epidermal growth factor receptor prevents the development of left ventricular hypertrophy. 1262 3

The nucleic acid sequence of the human gene, MUC17, indicates that this mucin contains an SEA domain, a transmembrane domain, and putative N-glycosylation sites in the carboxyl terminus. Mucins that possess an SEA domain are usually proteolytically cleaved within that domain to yield two subunits, the smaller of which is associated with the surface membrane. Homogenates of ASPC-1 pancreatic cancer cells showed three main bands of immunoreactivity with alpha-SEA (a polyclonal antibody directed against a site downstream of the postulated cleavage site) after SDS-PAGE and Western blotting (38, 45, and 49 kDa). Experiments utilizing N-glycan specific hydrolases showed that the 38 kDa band contained high mannose glycans whereas the 45 and 49 kDa bands contained complex-type glycans. Only two smaller alpha-SEA reactive bands (30 and 32 kDa) were present after cells had been treated with the N-glycosylation inhibitor tunicamycin. Surface biotinylation studies showed that only the forms possessing complex-type N-glycans were localized to the cell surface. Both tunicamycin and brefeldin A, an inhibitor of protein transport, reduced surface localization. In summary, our results indicate that the surface localization of the smaller subunit of MUC17 is dependent on its N-glycosylation status.
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PMID:N-glycosylation is required for the surface localization of MUC17 mucin. 1288 91

Cold exposure provides a reproducible model of improved glucose turnover accompanied by reduced steady state and glucose-induced insulin levels. In the present report we performed immunoprecipitation and immunoblot studies to evaluate the initial and intermediate steps of the insulin-signalling pathway in white and brown adipose tissues, liver and skeletal muscle of rats exposed to cold. Basal and glucose-induced insulin secretion were significantly impaired, while glucose clearance rates during a glucose tolerance test and the constant for glucose decay during a 15 min insulin tolerance test were increased, indicating a significantly improved glucose turnover and insulin sensitivity in rats exposed to cold. Evaluation of protein levels and insulin-induced tyrosine (insulin receptor, insulin receptor substrates (IRS)-1 and -2, ERK (extracellular signal-related kinase)) or serine (Akt; protein kinase B) phosphorylation of proteins of the insulin signalling cascade revealed a tissue-specific pattern of regulation of the molecular events triggered by insulin such that in white adipose tissue and skeletal muscle an impaired molecular response to insulin was detected, while in brown adipose tissue an enhanced response to insulin was evident. In muscle and white and brown adipose tissues, increased 2-deoxy-D-glucose (2-DG) uptake was detected. Thus, during cold exposure there is a tissue-specific regulation of the insulin-signalling pathway, which seems to favour heat-producing brown adipose tissue. Nevertheless, muscle and white adipose tissue are able to take up large amounts of glucose, even in the face of an apparent molecular resistance to insulin.
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PMID:Cold exposure induces tissue-specific modulation of the insulin-signalling pathway in Rattus norvegicus. 1289 67

NUCLEI CAN BE ISOLATED FROM THE EGGS AND EMBRYOS OF THE SEA URCHIN BY A FOUR STEP METHOD: (1) washing with dextrose solution until the cells become weak, (2) cytolysis in 0.002 M Mg(++) solution, (3) homogenization of the cytolyzed cells by agitation, and (4) separation of the nuclei from the rest of the homogenate by centrifugation on a layered sucrose gradient. Contamination of the isolated nuclei is less than 1 per cent. The yield varies between 20 per cent and 80 per cent depending on the developmental stage used.
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PMID:The isolation of nuclei from eggs and embryos of the sea urchin. 1395 43

Paeoniflorin (PF) is an active glucoside in Shaoyao (peony root), and is transformed into an antispasmodic metabolite, paeonimetabolin-I (PM-I), by intestinal bacteria in the gut after oral administration of Shaoyao or Shaoyao-Gancao-tang (SGT, Shakuyaku-Kanzo-To in Japanese). SGT is a pain-relieving traditional Chinese formulation (Kampo-medicine in Japanese) and is often used together with antibacterial synthetic drugs, such as amoxicillin and metronidazole (AMPC-MET), in peptic ulcer therapy. Since the bioavailability of PF in SGT has been reported to be significantly reduced by co-administered antibacterial drugs, we investigated how to minimize this reducing effect of antibacterial treatment in the present study. We found that repetitive administration of SGT starting 24 h after AMPC-MET treatment rapidly restored the plasma PM-I concentration from SGT reduced by AMPC-MET, due to its restorative effect on the decreased PF-metabolizing activity of intestinal bacteria in rat feces. The present findings suggest that it may be clinically useful to administer SGT repetitively, starting 1 or 2 d after treatment with a mixture of AMPC-MET during their combination therapy, to accelerate the recovery of the reduced bioavailability of PF in SGT. Similar administration regimens may also be useful in other combination therapies involving traditional Chinese formulations and antibacterial synthetic drugs to ensure the efficacy of the bioactive glycosides in the formulations.
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PMID:Restorative effect of repetitive administration of Shaoyao-Gancao-tang on bioavailability of paeoniflorin reduced by antibacterial synthetic drugs treatment in rats. 1460 Apr 6


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