A2B adenosine receptor signaling attenuates acute lung injury by enhancing alveolar fluid clearance in mice

J Clin Invest. 2008 Oct;118(10):3301-15. doi: 10.1172/JCI34203.

Abstract

Although acute lung injury contributes significantly to critical illness, resolution often occurs spontaneously via activation of incompletely understood pathways. We recently found that mechanical ventilation of mice increases the level of pulmonary adenosine, and that mice deficient for extracellular adenosine generation show increased pulmonary edema and inflammation after ventilator-induced lung injury (VILI). Here, we profiled the response to VILI in mice with genetic deletions of each of the 4 adenosine receptors (ARs) and found that deletion of the A2BAR gene was specifically associated with reduced survival time and increased pulmonary albumin leakage after injury. In WT mice, treatment with an A2BAR-selective antagonist resulted in enhanced pulmonary inflammation, edema, and attenuated gas exchange, while an A2BAR agonist attenuated VILI. In bone marrow-chimeric A2BAR mice, although the pulmonary inflammatory response involved A2BAR signaling from bone marrow-derived cells, A2BARs located on the lung tissue attenuated VILI-induced albumin leakage and pulmonary edema. Furthermore, measurement of alveolar fluid clearance (AFC) demonstrated that A2BAR signaling enhanced amiloride-sensitive fluid transport and elevation of pulmonary cAMP levels following VILI, suggesting that A2BAR agonist treatment protects by drying out the lungs. Similar enhancement of pulmonary cAMP and AFC were also observed after beta-adrenergic stimulation, a pathway known to promote AFC. Taken together, these studies reveal a role for A2BAR signaling in attenuating VILI and implicate this receptor as a potential therapeutic target during acute lung injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine A2 Receptor Agonists
  • Adenosine A2 Receptor Antagonists
  • Aminopyridines / pharmacology
  • Animals
  • Chimera / metabolism
  • Extravascular Lung Water / metabolism*
  • Female
  • Gene Expression Regulation
  • Lung Injury*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Pneumonia / etiology
  • Pneumonia / genetics
  • Pulmonary Alveoli / drug effects
  • Pulmonary Alveoli / metabolism*
  • Pulmonary Alveoli / physiopathology
  • Receptor, Adenosine A2B / genetics
  • Receptor, Adenosine A2B / metabolism*
  • Receptors, Purinergic P1 / genetics
  • Signal Transduction*
  • Time Factors
  • Ventilators, Mechanical / adverse effects*
  • Xanthines / pharmacology

Substances

  • 1-propyl-8-(4-sulfophenyl)xanthine
  • Adenosine A2 Receptor Agonists
  • Adenosine A2 Receptor Antagonists
  • Aminopyridines
  • BAY 60-6583
  • Receptor, Adenosine A2B
  • Receptors, Purinergic P1
  • Xanthines