Agonist-induced down regulation of type 1 and type 3 inositol 1,4,5-tris-phosphate receptors in A7r5 and DDT1 MF-2 smooth muscle cells

Autor: Leo E. Deelman, Jan B. Parys, Robert H. Henning, Ludwig Missiaen, Henk Sipma, Humbert De Smedt, Rik Casteels, Sara Vanlingen
Jazyk: angličtina
Rok vydání: 1998
Předmět:
Calcium Channel Blockers/pharmacology
Physiology
Vascular/chemistry
Gene Expression
Receptors
Cytoplasmic and Nuclear
Down-Regulation/drug effects
Stimulation
Muscle
Smooth
Vascular
chemistry.chemical_compound
Adenosine Triphosphate
Genes
Reporter
Cricetinae
Receptors
Aorta/cytology
Inositol 1
4
5-Trisphosphate Receptors
Promoter Regions
Genetic
Receptor
Aorta
5-Trisphosphate Receptors
Voltage-dependent calcium channel
Transfection
Calcium Channel Blockers
Parasympathomimetics
cardiovascular system
Muscle
Smooth
Promoter Regions
Genetic/physiology
Muscle
Smooth
Vascular/chemistry
Histamine
Histamine/pharmacology
endocrine system
Cell type
Calcium/metabolism
Vasopressins
Down-Regulation
Receptors
Cytoplasmic and Nuclear/chemistry
Gene Expression/drug effects
Vasopressins/pharmacology
Biology
Protein degradation
Bradykinin
Promoter Regions
Parasympathomimetics/pharmacology
Animals
Humans
Channel blocker
Carbachol/pharmacology
Verapamil/pharmacology
Molecular Biology
Reporter
Calcium Channels/chemistry
Genetic/physiology
Cytoplasmic and Nuclear/chemistry
Cell Biology
Inositol 1
Molecular biology
Rats
carbohydrates (lipids)
Verapamil
chemistry
Bradykinin/pharmacology
Genes
Calcium
Carbachol
Calcium Channels
Adenosine Triphosphate/pharmacology
HeLa Cells
Zdroj: Cell calcium, 23(1), 11-21. Churchill Livingstone
ISSN: 0143-4160
DOI: 10.1016/s0143-4160(98)90070-7
Popis: Prolonged stimulation of rat A7r5 aortic smooth muscle cells with 3 mu M vasopressin, or of hamster DDT1 MF-2 smooth muscle cells with 10 mu M bradykinin or 100 mu M histamine led within 4 h to a 40-50% down-regulation of the type 1 InsP(3) receptor (InsP(3)R-1) and of the type 3 InsP(3) receptor (InsP(3)R-3). InsP(3)R down-regulation was a cell- and agonist-specific process, since several other agonists acting on PLC-coupled receptors did not change the expression level of the InsP(3)R isoforms in these cell types and since no agonist-induced down-regulation of InsP(3)Rs was observed in HeLa cells. Down-regulation of InsP(3)Rs was prevented by an inhibitor of proteasomal protease activity, N-acetyl-Leu-Leu-norleucinal (ALLN). The Ca2+ channel blocker verapamil (2 mu M) also induced InsP(3)R-l down-regulation (43%) in A7r5 cells, which was inhibited by ALLN. In A7r5 cells transiently transfected with a cDNA construct, bearing a luciferase coding sequence under control of the rat InsP(3)R-l promoter, reduced luciferase activity could be demonstrated upon stimulation of cells with vasopressin or verapamil. Thus, besides enhanced protein degradation, a reduction of InsP(3)R promoter activity might contribute to the down-regulation of InsP(3)Rs in A7r5 cells. We next investigated the effect of InsP(3)R down-regulation on Ca2+ responses in A7r5 cells. A rightward shift in the dose-response curve for InsP(3)-induced Ca2+ release was observed in permeabilized monolayers of vasopressin-pretreated A7r5 cells (EC50 630 nM and 400 nM for pretreated and non-pretreated cells, respectively). The Ca2+ responses to threshold doses of vasopressin were markedly reduced in intact vasopressin-pretreated cells. We conclude that prolonged agonist-exposure leads to down-regulation of InsP(3)Rs in A7r5 and DDT1 MF-2 smooth muscle cells. The mechanism of down-regulation likely involves proteasomal degradation and reduction of InsP(3)R promoter activity. Moreover, down-regulation of InsP(3)Rs resulted in desensitization of Ca2+ release from InsP(3) sensitive stores.
Databáze: OpenAIRE
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