title: Functional interdependence and colocalization of endothelial nitric oxide synthase and heat shock protein 90 in cerebral arteries.
abstract: Heat shock protein 90 (HSP90), an essential component of several signal transduction systems, participates in the activation of endothelial nitric oxide synthase (eNOS) in cells. The objective of the current study was to determine if HSP90 and eNOS were functionally interdependent and colocalized in the cerebral circulation. The authors used isometric force recording, cyclic 3'5'-guanosine monophosphate (cGMP) radioimmunoassay (RIA), and immunogold electron microscopy (EM) to study canine basilar artery. They found that geldanamycin (0.1 to 10 microg/mL), a selective HSP90 inhibitor, caused concentration-dependent contractions in arterial rings (n = 6 dogs). Contractions to geldanamycin were unaffected by a cyclooxygenase inhibitor, indomethacin (10 micromol/L; P < 0.05, n = 6). Functional evidence for interaction between HSP90 and nitric oxide (NO)-mediated signaling included observations that the contractile effect of geldanamycin was the following: (1) endothelium-dependent, (2) abolished by Ng-nitro-L-arginine methylester (L-NAME; 0.3 mmol/L), and (3) non-additive with the contractile effect of this NOS inhibitor (P < 0.01, n = 6 for each). Furthermore, RIA showed significant reduction in cGMP levels in arteries treated with geldanamycin (3 microg/mL; P < 0.02, n = 8), whereas immunogold EM demonstrated areas of colocalization of HSP90 and eNOS selectively in the cytoplasm of endothelial cells. The current findings suggest that in cerebral arteries, endothelial HSP90 plays an important role in modulation of basal NO-mediated signaling. This interaction may be particularly important in stress-induced up-regulation of HSP90 with subsequent alteration of vasomotor function.
authors.affiliation: Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA.
authors.forename: V G
authors.initials: VG
authors.lastname: Khurana
authors.forename: K
authors.initials: K
authors.lastname: Feterik
authors.forename: M J
authors.initials: MJ
authors.lastname: Springett
authors.forename: D
authors.initials: D
authors.lastname: Eguchi
authors.forename: V
authors.initials: V
authors.lastname: Shah
authors.forename: Z S
authors.initials: ZS
authors.lastname: Katusic
mesh_terms: D000818:Animals; D001488:Basilar Artery / Q000737:chemistry* / Q000201:enzymology*; D016227:Benzoquinones; D006152:Cyclic GMP / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry / Q000201:enzymology; D004285:Dogs; D004730:Endothelium, Vascular / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018841:HSP90 Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D047029:Lactams, Macrocyclic; D016253:Microscopy, Immunoelectron; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D011809:Quinones / Q000494:pharmacology; D011863:Radioimmunoassay; D014544:Uridine Triphosphate / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D011809:Quinones; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D006152:Cyclic GMP; D014544:Uridine Triphosphate; D019331:NG-Nitroarginine Methyl Ester; C001277:geldanamycin