Quantification of beta adrenergic receptor subtypes in beta-arrestin knockout mouse airways

PLoS One. 2015 Feb 6;10(2):e0116458. doi: 10.1371/journal.pone.0116458. eCollection 2015.

Abstract

In allergic asthma Beta 2 adrenergic receptors (β2ARs) are important mediators of bronchorelaxation and, paradoxically, asthma development. This contradiction is likely due to the activation of dual signaling pathways that are downstream of G proteins or β-arrestins. Our group has recently shown that β-arrestin-2 acts in its classical role to desensitize and constrain β2AR-induced relaxation of both human and murine airway smooth muscle. To assess the role of β-arrestins in regulating β2AR function in asthma, we and others have utilized β-arrestin-1 and -2 knockout mice. However, it is unknown if genetic deletion of β-arrestins in these mice influences β2AR expression in the airways. Furthermore, there is lack of data on compensatory expression of βAR subtypes when either of the β-arrestins is genetically deleted, thus necessitating a detailed βAR subtype expression study in these β-arrestin knockout mice. Here we standardized a radioligand binding methodology to characterize and quantitate βAR subtype distribution in the airway smooth muscle of wild-type C57BL/6J and β-arrestin-1 and β-arrestin-2 knockout mice. Using complementary competition and single-point saturation binding assays we found that β2ARs predominate over β1ARs in the whole lung and epithelium-denuded tracheobronchial smooth muscle of C57BL/6J mice. Quantification of βAR subtypes in β-arrestin-1 and β-arrestin-2 knockout mouse lung and epithelium-denuded tracheobronchial tissue showed that, similar to the C57BL/6J mice, both knockouts display a predominance of β2AR expression. These data provide further evidence that β2ARs are expressed in greater abundance than β1ARs in the tracheobronchial smooth muscle and that loss of either β-arrestin does not significantly affect the expression or relative proportions of βAR subtypes. As β-arrestins are known to modulate β2AR function, our analysis of βAR subtype expression in β-arrestin knockout mice airways sets a reference point for future studies exploiting these knockout mice in various disease models including asthma.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Arrestins / genetics
  • Arrestins / metabolism*
  • Asthma / genetics
  • Asthma / metabolism*
  • Asthma / pathology
  • Asthma / physiopathology
  • Bronchi / metabolism*
  • Bronchi / pathology
  • Bronchi / physiopathology
  • Humans
  • Mice
  • Mice, Knockout
  • Muscle Relaxation*
  • Muscle, Smooth / metabolism*
  • Muscle, Smooth / pathology
  • Muscle, Smooth / physiopathology
  • Receptors, Adrenergic, beta-2 / genetics
  • Receptors, Adrenergic, beta-2 / metabolism*
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / pathology
  • Respiratory Mucosa / physiopathology
  • Trachea / metabolism*
  • Trachea / pathology
  • Trachea / physiopathology
  • beta-Arrestin 1
  • beta-Arrestin 2
  • beta-Arrestins

Substances

  • ARRB1 protein, human
  • ARRB2 protein, human
  • Arrb1 protein, mouse
  • Arrb2 protein, mouse
  • Arrestins
  • Receptors, Adrenergic, beta-2
  • beta-Arrestin 1
  • beta-Arrestin 2
  • beta-Arrestins