title: Essential role of the 90-kilodalton heat shock protein in mediating nongenomic estrogen signaling in coronary artery smooth muscle.
abstract: Under normal physiological conditions, estrogen is a coronary vasodilator, and this response involves production of NO from endothelial cells. In addition, estrogen also stimulates NO production in coronary artery smooth muscle (CASM); however, the molecular basis for this nongenomic effect of estrogen is unclear. The purpose of this study was to investigate a potential role for the 90-kDa heat shock protein (Hsp90) in estrogen-stimulated neuronal nitric-oxide synthase (nNOS) activity in coronary artery smooth muscle. 17Beta-estradiol produced a concentration-dependent relaxation of endothelium-denuded porcine coronary arteries in vitro, and this response was attenuated by inhibiting Hsp90 function with 1 microM geldanamycin (GA) or 100 microg/ml radicicol (RAD). These inhibitors also prevented estrogen-stimulated NO production in human CASM cells and reversed the stimulatory effect of estrogen on calcium-activated potassium (BK(Ca)) channels. These functional studies indicated a role for Hsp90 in coupling estrogen receptor activation to NOS stimulation in CASM. Furthermore, coimmunoprecipitation studies demonstrated that estrogen stimulates bimolecular interaction of immunoprecipitated nNOS with Hsp90 and that either GA or RAD could inhibit this association. Blocking estrogen receptors with ICI182780 (fulvestrant) also prevented this association. These findings indicate an essential role for Hsp90 in nongenomic estrogen signaling in CASM and further suggest that Hsp90 might represent a prospective therapeutic target to enhance estrogen-stimulated cardiovascular protection.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, Georgia, USA. ghan@mcg.edu
authors.forename: Guichun
authors.initials: G
authors.lastname: Han
authors.forename: Handong
authors.initials: H
authors.lastname: Ma
authors.forename: Rajesh
authors.initials: R
authors.lastname: Chintala
authors.forename: David J R
authors.initials: DJ
authors.lastname: Fulton
authors.forename: Scott A
authors.initials: SA
authors.lastname: Barman
authors.forename: Richard E
authors.initials: RE
authors.lastname: White
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism / Q000494:pharmacology*; D000077267:Fulvestrant; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D006801:Humans; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000187:drug effects / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D034421:Sus scrofa; D014664:Vasodilation / Q000187:drug effects
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D004965:Estrogen Antagonists; D004967:Estrogens; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D051036:Large-Conductance Calcium-Activated Potassium Channels; D018942:Macrolides; D000077267:Fulvestrant; D009569:Nitric Oxide; D004958:Estradiol; D052248:Nitric Oxide Synthase Type I; C035359:monorden; D019331:NG-Nitroarginine Methyl Ester; C001277:geldanamycin