Attenuated Desensitization of β-Adrenergic Receptor by Water-Soluble N-Nitrosamines that Induce S-Nitrosylation Without Nitric Oxide Release
Rationale: 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 due 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 GSNO, simultaneously generate nitric oxide (NO), which has been demonstrated to operate for cardiovascular protection.
Objective: We examine whether S-nitrosylation without NO generation inhibits desensitization of β2-AR by GRK2. We thus aim to synthesize compounds that specifically induce S-nitrosylation.
Methods and 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 HEK293 cells expressing FLAG-tagged human β2-AR and in rat cardiac myocytes. They inhibit isoproterenol-dependent phosphorylation and internalization of β2-AR. Indeed, they nitrosylate GRK2 in vitro and in cells and their S-nitrosylation of GRK2 likely underlies their inhibition of β2-AR desensitization.
Conclusions: Compounds that induce S-nitrosylation without NO release inhibit GRK2 and attenuate β2-AR desensitization. Developing water-soluble drugs that specifically induce S-nitorsylation may be a promising therapeutic strategy for heart failure.
- Received July 15, 2012.
- Accepted December 4, 2012.
- Copyright © 2012, American Heart Association