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Identification and pharmacological characterization of the prostaglandin FP receptor and FP receptor variant complexes
- Source :
- British Journal of Pharmacology
- Publication Year :
- 2008
-
Abstract
- Background and purpose: A prostamide analogue, bimatoprost, has been shown to be effective in reducing intraocular pressure, but its precise mechanism of action remains unclear. Hence, to elucidate the molecular mechanisms of this effect of bimatoprost, we focused on pharmacologically characterizing prostaglandin FP receptor (FP) and FP receptor variant (altFP) complexes. Experimental approach: FP receptor mRNA variants were identified by reverse transcription-polymerase chain reaction. The FP-altFP4 heterodimers were established in HEK293/EBNA cells co-expressing FP and altFP4 receptor variants. A fluorometric imaging plate reader was used to study Ca2+ mobilization. Upregulation of cysteine-rich angiogenic protein 61 (Cyr61) mRNA was measured by Northern blot analysis, and phosphorylation of myosin light chain (MLC) by western analysis. Key results: Six splicing variants of FP receptor mRNA were identified in human ocular tissues. Immunoprecipitation confirmed that the FP receptor is dimerized with altFP4 receptors in HEK293/EBNA cells co-expressing FP and altFP4 receptors. In the studies of the kinetic profile for Ca2+ mobilization, prostaglandin F2α (PGF2α) elicited a rapid increase in intracellular Ca2+ followed by a steady state phase. In contrast, bimatoprost elicited an immediate increase in intracellular Ca2+ followed by a second phase. The prostamide antagonist, AGN211335, selectively and dose-dependently inhibited the bimatoprost-initiated second phase of Ca2+ mobilization, Cyr61 mRNA upregulation and MLC phosphorylation, but did not block the action of PGF2α. Conclusion and implications: Bimatoprost lacks effects on the FP receptor but may interact with the FP-altFP receptor heterodimer to induce alterations in second messenger signalling. Hence, FP-altFP complexes may represent the underlying basis of bimatoprost pharmacology.
- Subjects :
- calcium signalling
Myosin Light Chains
Blotting, Western
Molecular Sequence Data
Receptors, Prostaglandin
Dinoprost
Eye
Transfection
Cell Line
Immediate-Early Proteins
Molecular and Cellular Mechanisms
Humans
prostamide
Amino Acid Sequence
RNA, Messenger
Phosphorylation
Dose-Response Relationship, Drug
Reverse Transcriptase Polymerase Chain Reaction
Genetic Variation
Cloprostenol
Blotting, Northern
Amides
Research Papers
receptor dimerization
Alternative Splicing
Kinetics
Bimatoprost
Intercellular Signaling Peptides and Proteins
Calcium
prostaglandin
Dimerization
Cysteine-Rich Protein 61
Signal Transduction
intraocular pressure
Subjects
Details
- ISSN :
- 00071188
- Volume :
- 154
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- British journal of pharmacology
- Accession number :
- edsair.pmid..........e1134e7535062ae0902b635abd5eb216