Respiratory syncytial virus induces insensitivity to beta-adrenergic agonists in mouse lung epithelium in vivo

Am J Physiol Lung Cell Mol Physiol. 2007 Aug;293(2):L281-9. doi: 10.1152/ajplung.00458.2006. Epub 2007 Apr 13.

Abstract

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants and children worldwide. We wished to determine whether intratracheal administration of beta-agonists improved alveolar fluid clearance (AFC) across the distal respiratory epithelium of RSV-infected mice. Following intranasal infection with RSV strain A2, AFC was measured in anesthetized, ventilated BALB/c mice by instillation of 5% BSA into the dependent lung. We found that direct activation of protein kinase A by forskolin or 8-bromo-cAMP increased AFC at day 2 after infection with RSV. In contrast, short- and long-acting beta-agonists had no effect at either day 2 or day 4. Insensitivity to beta-agonists was not a result of elevated plasma catecholamines or lung epithelial cell beta-adrenergic receptor degradation. Instead, RSV-infected mice had significantly higher levels of phosphorylated PKCzeta in the membrane fractions of their lung epithelial cells. In addition, insensitivity to beta-agonists was mediated in a paracrine fashion by KC (the murine homolog of CXCL8) and reversed by inhibition of either PKCzeta or G protein-coupled receptor kinase 2 (GRK2). These results indicate that insufficient response to beta-agonists in RSV may be caused, at least in part, by impaired beta-adrenergic receptor signaling, as a consequence of GRK2-mediated uncoupling of beta-adrenergic receptors from adenylyl cyclase.

Publication types

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

MeSH terms

  • Adrenergic beta-2 Receptor Agonists
  • Adrenergic beta-Agonists / pharmacology
  • Animals
  • Catecholamines / metabolism
  • Chemokine CXCL1
  • Chemokines, CXC / pharmacology
  • Colforsin / pharmacology
  • Extravascular Lung Water / metabolism
  • Female
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Phosphorylation
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism
  • Protein Kinase Inhibitors / pharmacology
  • Pulmonary Alveoli / metabolism
  • Pulmonary Alveoli / virology
  • Receptors, Adrenergic, beta-2 / metabolism*
  • Respiratory Mucosa / metabolism*
  • Respiratory Mucosa / virology*
  • Respiratory Syncytial Virus Infections / metabolism*
  • Respiratory Syncytial Virus, Human / metabolism*
  • Specific Pathogen-Free Organisms
  • Terbutaline / pharmacology

Substances

  • Adrenergic beta-2 Receptor Agonists
  • Adrenergic beta-Agonists
  • Catecholamines
  • Chemokine CXCL1
  • Chemokines, CXC
  • Cxcl1 protein, mouse
  • Protein Kinase Inhibitors
  • Receptors, Adrenergic, beta-2
  • Colforsin
  • protein kinase C zeta
  • Protein Kinase C
  • Terbutaline