title: Attenuated desensitization of β-adrenergic receptor by water-soluble N-nitrosamines that induce S-nitrosylation without NO release.
abstract: BACKGROUND
  The clinical problem of loss of β-adrenergic receptor (β-AR) response, both in the pathogenesis of heart failure and during therapeutic application of β-agonists, is attributable, at least in part, to desensitization, internalization, and downregulation of the receptors. In the regulation of β-AR signaling, G protein-coupled receptor kinase 2 (GRK2) primarily phosphorylates agonist-occupied β-ARs, and this modification promotes desensitization, internalization, and downregulation of β-ARs. It has been demonstrated that GRK2 is inhibited by its S-nitrosylation. However, compounds that induce S-nitrosylation, such as S-nitrosoglutathione, simultaneously generate NO, which has been demonstrated to operate for cardiovascular protection.
  
  
  OBJECTIVE
  We examine whether S-nitrosylation without NO generation inhibits desensitization of β(2)-AR by GRK2. We thus aim to synthesize compounds that specifically induce S-nitrosylation.
  
  
  RESULTS
  We have developed water-soluble N-nitrosamines that have S-nitrosylating activity but lack NO-generating activity. These compounds, at least partly, rescue β-AR from desensitization in HEK 293 cells expressing FLAG-tagged human β(2)-AR and in rat cardiac myocytes. They inhibit isoproterenol-dependent phosphorylation and internalization of β(2)-AR. Indeed, they nitrosylate GRK2 in vitro and in cells, and their S-nitrosylation of GRK2 likely underlies their inhibition of β(2)-AR desensitization.
  
  
  CONCLUSIONS
  Compounds that induce S-nitrosylation without NO release inhibit GRK2 and attenuate β(2)-AR desensitization. Developing water-soluble drugs that specifically induce S-nitrosylation may be a promising therapeutic strategy for heart failure.
authors.affiliation: Department of Endocrinology and Nephrology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Makita
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kabasawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Otani
authors.lastname: Firman
authors.forename: Junichiro
authors.initials: J
authors.lastname: Sato
authors.forename: Makiko
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Michio
authors.initials: M
authors.lastname: Nakaya
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nishihara
authors.forename: Masaomi
authors.initials: M
authors.lastname: Nangaku
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurose
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ohwada
authors.forename: Taroh
authors.initials: T
authors.lastname: Iiri
mesh_terms: D000818:Animals; D057809:HEK293 Cells; D006801:Humans; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009602:Nitrosamines / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D051381:Rats; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D012995:Solubility / Q000187:drug effects; D014867:Water / Q000737:chemistry / Q000502:physiology*
chemical_list: D009602:Nitrosamines; D018343:Receptors, Adrenergic, beta-2; D014867:Water; D009569:Nitric Oxide