Agonists and hydrogen peroxide mediate hyperoxidation of β2-adrenergic receptor in airway epithelial cells: Implications for tachyphylaxis to β2-agonists in constrictive airway disorders - 11/11/23
Abstract |
Asthma and other airway obstructive disorders are characterized by heightened inflammation and excessive airway epithelial cell reactive oxygen species (ROS), which give rise to a highly oxidative environment. After decades of use, β2-adrenergic receptor (β2AR) agonists remain at the forefront of treatment options for asthma, however, chronic use of β2-agonists leads to tachyphylaxis to the bronchorelaxant effects, a phenomenon that remains mechanistically unexplained. We have previously demonstrated that β2AR agonism increases ROS generation in airway epithelial cells, which upholds proper receptor function via feedback oxidation of β2AR cysteine thiolates to Cys-S-sulfenic acids (Cys-SOH). Our previous results also demonstrate that prevention of normal redox cycling of this post-translational oxi-modification back to the thiol prevents proper receptor function. Given that Cys-S-sulfenic acids can be irreversibly overoxidized to Cys-S-sulfinic (Cys-SO2H) or S-sulfonic (Cys-SO3H) acids, which are incapable of further participation in redox reactions, we hypothesized that β2-agonist tachyphylaxis may be explained by hyperoxidation of β2AR to S-sulfinic acids. Here, using airway epithelial cell lines and primary small airway epithelial cells from healthy and asthma-diseased donors, we show that β2AR agonism generates H2O2 in a receptor and NAPDH oxidase-dependent manner. We also demonstrate that acute and chronic receptor agonism can facilitate β2AR S-sulfination, and that millimolar H2O2 concentrations are deleterious to β2AR-mediated cAMP formation, an effect that can be rescued to a degree in the presence of the cysteine-donating antioxidant N-acetyl-L-cysteine. Our results reveal that the oxidative state of β2AR may contribute to receptor functionality and may, at least in part, explain β2-agonist tachyphylaxis.
Le texte complet de cet article est disponible en PDF.Highlights |
• | Agonism of β2AR induces H2O2 generation in small airway epithelial cells. |
• | β2AR-mediated H2O2 generation is dependent on NADPH-oxidase isozymes. |
• | β2AR agonists or H2O2 facilitate oxidation of β2AR via cysteine-S-sulfination. |
• | H2O2 treatment can modulate β2AR-driven cAMP formation. |
• | The oxidation state of β2AR may regulate its function in the airway epithelium. |
List of abbreviations : AC, A-SAEC, β2AR, cAMP - adenosine 3', H2O2, PDE, ROS, SAEC, SOH, SO2H
Keywords : Beta-adrenergic receptors, Reactive oxygen species, Asthma, Airway epithelial cells, Cyclic AMP
Plan
Vol 168
Article 115763- décembre 2023 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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