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Thrombin-promoted release of UDP-glucose from human astrocytoma cells.
- Source :
-
British Journal of Pharmacology . Apr2008, Vol. 153 Issue 7, p1528-1537. 10p. 5 Graphs. - Publication Year :
- 2008
-
Abstract
- Background and purpose:The P2Y14 receptor is activated by UDP-sugars, most potently by UDP-glucose, but not by free nucleotides, suggesting that UDP-glucose is the cognate agonist for this receptor. However, evidence for regulated release of UDP-glucose is scarce. In the present study, the occurrence of receptor-promoted release of UDP-glucose was investigated, using 1321N1 human astrocytoma cells.Experimental approach:UDP-glucose release and hydrolysis were measured using HPLC-based techniques. Phospholipase C activation and actin cytoskeleton reorganization were assessed by measuring inositol phosphate formation and fluorescence confocal microscopy, respectively.Key results:Thrombin and the protease-activating receptor-1 (PAR1) peptide TFLLRNPNDK (PAR1-AP) evoked the release of UDP-glucose and ATP, which was accompanied by enhanced inositol phosphate formation. Although carbachol promoted fourfold greater inositol phosphate formation than thrombin, it failed to promote nucleotide release. Thrombin-promoted nucleotide release was inhibited by BAPTA-AM, brefeldin A and cytochalasin D, and was insensitive to Pertussis toxin and PI3-kinase inhibitors. Thrombin, but not carbachol, induced actin cytoskeleton reorganization, a hallmark of Rho activation in 1321N1 cells. However, PAR-promoted UDP-glucose release was not affected by Rho kinase inhibition.Conclusions and implications:PAR1-evoked UDP-glucose release reflected a Ca2+-dependent mechanism, engaging additional signalling independently of Gi and Rho kinase activation and requiring a functional actin cytoskeleton and Golgi structures. Our study demonstrates the occurrence of Ca2+-dependent release of UDP-glucose from astrocytoma cells in response to a physiologically relevant stimulus, that is, a G-protein-coupled receptor agonist. Given the presence of P2Y14 receptors in astrocytes, UDP-glucose may have important autocrine/paracrine functions in the brain.British Journal of Pharmacology (2008) 153, 1528–1537; doi:10.1038/sj.bjp.0707692; published online 21 January 2008 [ABSTRACT FROM AUTHOR]
- Subjects :
- *THROMBIN
*GLUCOSE
*ASTROCYTOMAS
*NUCLEOTIDES
*PHOSPHOLIPASE C
*CALCIUM metabolism
*MUSCLE protein metabolism
*NUCLEOTIDE metabolism
*CELL lines
*CELL receptors
*CELLULAR signal transduction
*PHYSICAL & theoretical chemistry
*CYTOPLASM
*ESTERASES
*GLIOMAS
*HIGH performance liquid chromatography
*MEMBRANE proteins
*PARASYMPATHOMIMETIC agents
*PHOSPHOTRANSFERASES
*RESEARCH funding
*PHARMACODYNAMICS
Subjects
Details
- Language :
- English
- ISSN :
- 00071188
- Volume :
- 153
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- British Journal of Pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 31470616
- Full Text :
- https://doi.org/10.1038/sj.bjp.0707692