| 1. |
- Alling, Christer, et al.
(författare)
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Adaptation of signal transduction in brain
- 1994
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Ingår i: EXS. - 1023-294X. ; 71, s. 19-28
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Tidskriftsartikel (refereegranskat)abstract
- Cell culture models were used to study the effects of long-term ethanol exposure on neuronal cells. Effects on phospholipase C and phospholipase D mediated signal transduction were investigated by assaying receptor-binding, G protein function, activities of lipases, formation of second messengers and c-fos mRNA. The signal transduction cascades displayed abnormal activities from 2 to 7 days of exposure which differed from the acute effects. Phosphatidylethanol formed by phospholipase D is an abnormal lipid that may harmfully affect nerve cell function.
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| 2. |
- Alling, Christer, et al.
(författare)
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Evaluation of ethanol effects on PLC signal transduction pathways using cell lines of neuronal origin
- 1993
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Ingår i: Alcohol and alcoholism. Supplement. - 1358-6173. ; 2, s. 295-299
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Tidskriftsartikel (refereegranskat)abstract
- Human neuroblastoma cells SH-SY5Y and neuroblastoma-glioma cells NG 108-15 have been used as models for the elucidation of the effects of ethanol on receptor-mediated phospholipase C activity, c-fos mRNA expression and protein kinase C activity. Cells were exposed to ethanol (0-200 mM) for varying periods up to seven days. Agonist stimulated events were obtained in NG 108-15 cells with bradykinin and in SH-SY5Y cells with carbachol. Chronic ethanol exposure reduced the agonist-stimulated formation of inositol 1,4,5-trisphosphate in NG 108-15 cells and in SH-SY5Y cells. 100 mM ethanol for seven days increased the membrane bound and cytosolic forms of protein kinase C activity in SH-SY5Y cells. Carbachol (1 mM) induced a maximal c-fos mRNA response after 40 minutes in SH-SY5Y cells, an effect that could be mimicked through protein kinase C stimulation by phorbol esters.
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| 3. |
- Alling, Christer, et al.
(författare)
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Muscarinic receptor-stimulated expression of c-fos in neuroblastoma cells
- 1994
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Ingår i: Alcohol and alcoholism. Supplement. - 1358-6173. ; :2, s. 103-108
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Tidskriftsartikel (refereegranskat)abstract
- The intracellular signal cascade transducing muscarinic-receptor-stimulation to gene expression was investigated in human neuroblastoma SH-SY5Y cells. Naive and ethanol-exposed SH-SU5Y cells were stimulated with carbachol (CCh) and inositol 1,4-5-trisphosphate (IP3), 1,2-diacylglycerol (DAG), and c-fos mRNA levels were analyzed using a radioreceptor assay (IP3) thin-layer chromatography (DAG) and Northern blot (c-fos mRNA). Application of the muscarinic agonist CCh induced a rapid increase in (IP3), peaking within seconds after the CCh-addition. There was also an accumulation of DAG reaching maximum after 5 min of receptor-stimulation. Stimulation with CCh also induced expression of the immediate-early gene c-fos in these cells. These events were mediated via muscarinic M1 receptors and the inhibitory effects of H7, staurosporin, and RO31-7549 on the c-fos expression indicated that it was mediated via protein kinase C. Acute exposure to 100 mM ethanol inhibited the formation of IP3 and the expression of c-fos. These effects were due to an increase in the EC50 of CCh for the events. Exposure to 100 mM ethanol for 4 days caused a potentiation of these two events. The EC50 was unaffected but the maximal response was increased. These data indicate that this signal transduction system is inhibited by acute exposure to 100 mM ethanol, an effect that is compensated for after exposure to ethanol for 4 days.
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| 4. |
- Ding, W Q, et al.
(författare)
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Acute ethanol exposure attenuates expression of junD in human neuroblastoma cells
- 1998
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Ingår i: Neurochemistry International. - 0197-0186. ; 33:6, s. 525-530
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Tidskriftsartikel (refereegranskat)abstract
- This study describes the effects of acute ethanol exposure on the mRNA levels of c-jun,junB and junD in the human neuroblastoma SH-SY5Y cell line. An acute exposure to 100 mM ethanol did not influence the basal and phorbol ester-induced expression of c-jun and junB, whereas the basal mRNA level of junD was attenuated by 30%. This effect was dose- and time-dependent with maximal inhibition being detected 2 h after 100 mM ethanol treatment and the mRNA levels gradually returned towards normal afterwards. Ethanol also inhibited phorbol ester-induced expression of junD. The fact that ethanol did not influence degradation of the junD mRNA suggests that acute ethanol suppresses the transcription of the gene. These results indicate that acute ethanol exerts different effects on expression of Jun transcription factors, suggesting that as compared to c-jun and junB, the junD gene may be more sensitive to acute ethanol treatment in neuronal cells.
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| 5. |
- Ding, W Q, et al.
(författare)
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Effects of ethanol on muscarinic receptor-stimulated c-fos expression in human neuroblastoma cells
- 1997
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 46:1-2, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- The effect of ethanol exposure on muscarinic receptor-stimulated expression of c-fos was investigated in SH-SY5Y cells. Four days of ethanol exposure enhanced carbachol-stimulated c-fos mRNA expression, analyzed with Northern blot, and Fos/AP-1 binding activity, measured with gel mobility super shift assay. Pre-incubation with muscarinic antagonists or the protein kinase C inhibitor GF109203X demonstrated that, in both control and ethanol-treated cells, carbachol-induced c-fos expression was mediated via muscarinic M1 receptors and to a large extent through protein kinase C. However, phorbol ester-induced c-fos expression was unaffected in ethanol-treated cells. Acute exposure to ethanol caused a suppression of both carbachol- and phorbol ester-stimulated c-fos expression. These results demonstrate that muscarinic receptor-stimulated gene expression is sensitive to both acute and long-term ethanol exposure.
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| 6. |
- Ding, Wei-Qun, et al.
(författare)
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Ethanol exposure increases expression of c-jun and junD in human neuroblastoma cells
- 1996
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Ingår i: NeuroReport. - 1473-558X. ; 7:13, s. 2191-2195
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effect of ethanol exposure on the expression of fos and jun genes. Exposure of human neuroblastoma SH-SY5Y cells to ethanol for 2-4 days caused a dose-dependent increase in c-jun and junD mRNA levels, whereas mRNAs for c-fos, fosB and junB were not detectable in control or ethanol-treated cells. Four days of ethanol exposure also enhanced the AP-1 binding activity. Experiments with actinomycin D demonstrated that ethanol did not influence the degradation of c-jun and junD mRNAs. These results demonstrate that long-term exposure to ethanol increases c-jun and junD expression. This effect may be one of the mechanisms through which ethanol influences the gene regulatory system in neuronal cells.
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| 7. |
- Ding, Wei-Qun, et al.
(författare)
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Ethanol exposure potentiates fosB and junB expression induced by muscarinic receptor stimulation in neuroblastoma SH-SY5Y cells
- 1998
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Ingår i: Alcoholism: Clinical and Experimental Research. - : Wiley. - 0145-6008 .- 1530-0277. ; 22:1, s. 225-230
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Tidskriftsartikel (refereegranskat)abstract
- Muscarinic receptor stimulation and activation of protein kinase C cause an increase in fosB and junB transcripts in human neuroblastoma SH-SY5Y cells. In this study, the effect of long-term ethanol exposure on these events was investigated. Carbachol-stimulated fosB and junB expression was elevated in ethanol-exposed cells compared with control cells. The potentiation was time- and dose-dependent on ethanol. Preincubation with muscarinic antagonists or protein kinase C inhibitor demonstrated that the carbachol-stimulated increase in fosB and junB mRNA levels was primarily mediated via M1 receptors and dependent on the activity of protein kinase C in both control and ethanol-exposed cells. Long-term ethanol exposure did not influence the expression of fosB and junB induced by activation of protein kinase C with phorbol ester. These results demonstrate that the muscarinic receptor-stimulated fosB and junB expression is sensitive to ethanol exposure in SH-SY5Y cells, suggesting that these genes participate in the regulation of neuronal function in response to chronic ethanol treatment.
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| 8. |
- Ding, Wei-Qun, et al.
(författare)
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Stimulation of muscarinic receptors induces expression of individual fos and jun genes through different transduction pathways
- 1998
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 70:4, s. 1722-1729
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Tidskriftsartikel (refereegranskat)abstract
- The transduction pathways coupling muscarinic receptors to induction of fos and jun genes were investigated in neuroblastoma SH-SY5Y cells. Stimulation with carbachol induced expression of c-fos, fosB, c-jun, junB, and junD. This effect was abolished by pretreatment with atropine, indicating an involvement of muscarinic receptors. These genes were also induced by activation of protein kinase C with phorbol ester or by elevating the intracellular Ca2+ concentration with a Ca2+ ionophore. The Ca2+ effect was inhibited by KN-62, suggesting an induction through Ca2+/calmodulin-dependent kinase II. Inhibition of protein kinase C with GF109203X suppressed the carbachol-stimulated increase in mRNA levels of c-fos, fosB, and junB by approximately 70% but had only minor effects on the expression of c-jun and junD. On the other hand, preincubation with KN-62 attenuated the carbachol-induced increase in c-jun and junD expression by 70% but had no effect on c-fos, fosB, and junB mRNA levels. Simultaneous inhibition of both protein kinase C and Ca2+/calmodulin-dependent kinase II completely abolished the carbachol-stimulated expression of c-jun and junD, but c-fos, fosB, and junB were still expressed to a certain extent under this condition. Comparison of the inhibitory effects of GF109203X and Go 6976 suggests the involvement of classical protein kinase C isozymes in muscarinic receptor-stimulated expression of fos and jun genes. These results demonstrate that the muscarinic receptor-induced expression of individual fos and jun genes is regulated via different pathways, primarily protein kinase C or Ca2+/calmodulin-dependent kinase II.
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| 9. |
- Larsson, Christer, et al.
(författare)
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An okadaic acid-sensitive protein phosphatase counteracts protein kinase C-induced phosphorylation in SH-SY5Y cells
- 1993
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Ingår i: Cellular Signalling. - 1873-3913. ; 5:3, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- Protein phosphorylation and subsequent dephosphorylation was studied in digitonin-permeabilized neuroblastoma SH-SY5Y cells by measuring the incorporation of [32P]phosphate into myelin basic protein (MBP). 1,2-Dioctanoyl-sn-glycerol (DOG) and calcium synergistically induced phosphorylation of MBP, which was inhibited by the protein kinase C (PKC) pseudosubstrate peptide (PKC19-36). The phosphorylation increased for 10 min when a net dephosphorylation started to appear. The dephosphorylation was inhibited by okadaic acid. Regardless of calcium concentration, the presence of DOG was necessary for significant effects of okadaic acid on MBP phosphorylation. H7 and staurosporine dose-dependently inhibited the phosphorylation of MBP, induced by DOG and calcium in the presence of okadaic acid. Different PKC pseudosubstrate peptides were applied and all showed an inhibitory effect on the phosphorylation of MBP under these conditions. These results demonstrate the presence, in SH-SY5Y cells, of a protein phosphatase, possibly protein phosphatase 2A, with a high basal activity that counteracts PKC-induced phosphorylation.
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| 10. |
- Larsson, Christer, et al.
(författare)
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Calmidazolium inhibits muscarinic receptor-mediated PLC activation in SH-SY5Y cells
- 1995
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Ingår i: NeuroReport. - 1473-558X. ; 6:9, s. 1333-1337
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effect of a calmodulin antagonist, calmidazolium, on the muscarinic receptor-mediated increase in inositol 1,4,5-trisphosphate [I(1,4,5)P3] in SH-SY5Y cells. Exposure to 10 microM calmidazolium suppressed the initial I(1,4,5)P3 peak increase (IC50 1 microM) whereas the steady-state was less affected. Furthermore, calmidazolium displayed non-competitive antagonistic properties of [3H]quinuclidinyl benzylate binding to intact SH-SY5Y cells and to membranes from these cells. These effects were also obtained with another calmodulin inhibitor, trifluoperazine (10 microM). These results demonstrate that novel finding that the calmodulin inhibitors calmidazolium and trifluoperazine act as non-competitive muscarinic antagonists in SH-SY5Y cells and inhibit muscarinic receptor-stimulated phospholipase C activation in these cells.
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