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Impact of Paroxetine on Proximal β‐adrenergic Receptor Signaling
Author(s) -
Guo Shuchi,
Carter Rhonda,
Tilley Douglas
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.992.3
Subject(s) - paroxetine , medicine , beta adrenergic receptor kinase , endocrinology , internalization , stimulation , desensitization (medicine) , citalopram , g protein coupled receptor , adenylyl cyclase , receptor , chemistry , pharmacology , biology , serotonin
β‐adrenergic receptor (βAR) signaling normally relays sympathetic signals to the heart, but during the development of heart failure, aberrant βAR signaling and desensitization can contribute to pathological remodeling. Thus, therapeutics targeting factors involved in the regulation of βAR signaling have been investigated extensively, including G protein‐coupled receptor kinase (GRK) inhibition. Via structural and biochemical analyses, the selective serotonin reuptake inhibitor (SSRI) paroxetine has recently been identified as a GRK2 inhibitor that enhances βAR‐dependent cardiomyocyte and cardiac contractility and reverses cardiac dysfunction and myocardial βAR expression in mouse models of heart failure, whereas another SSRI (fluoxetine) does not. Despite these functional outcomes, consistent with diminished βAR desensitization, the proximal βAR signaling mechanisms sensitive to paroxetine have not been reported. In this project, we aimed to determine whether paroxetine indeed prevents classic βAR desensitization mechanisms at a molecular level. Here we have applied fluorescence resonance energy transfer (FRET) assays to perform a real‐time comparative assessment of the effects of paroxetine versus fluoxetine on cyclic AMP (cAMP) production, β‐arrestin recruitment and interaction between βAR and epidermal growth factor receptor (EGFR). We also investigated whether paroxetine modulates βAR internalization and phosphorylation following catecholamine stimulation via fluorescent microscopy and western blotting. Our results indicate that paroxetine indeed inhibits βAR phosphorylation, β‐arrestin recruitment and internalization in response to catecholamine stimulation, while fluoxetine does not. Further, our data suggests that paroxetine impacts Gs protein/adenylyl cyclase‐dependent cAMP generation in response to catecholamine and acts to disrupt βAR association with EGFR. Thus, paroxetine inhibits classic βAR desensitization mechanisms consistent with GRK inhibition and may be a useful pharmacological tool for studying proximal GPCR signaling.