Effects of distension on airway inflammation and venular P-selectin expression

Am J Physiol Lung Cell Mol Physiol. 2008 Nov;295(5):L941-8. doi: 10.1152/ajplung.90447.2008. Epub 2008 Sep 19.

Abstract

We previously have shown in mice and rats, enhanced leukocyte recruitment to airway postcapillary venules after excessive distention imposed by the application of positive end-expiratory pressure. Because P-selectin was shown to be essential for this outcome, we sought to establish an in vitro endothelial cell model and determine the mechanisms whereby mechanical distension alters adhesion molecule expression. P-selectin surface expression on mouse jugular vein endothelial cells exposed to cyclic stretch (5 or 20% elongation for 5 min; Flexercell) were compared with static cells. The larger, pathophysiological regimen of cyclic stretch showed a 54% increase in P-selectin expression after stretch compared with static cells. This response was attenuated but confirmed in tracheal venular endothelium (29% increase). We questioned whether these changes were dependent on increases in intracellular Ca(2+) through voltage-gated Ca(2+) channels. The stretch-induced increase in P-selectin expression was substantially decreased by pretreatment with the T-type Ca(2+) channel inhibitor mibefradil (76% inhibition). Furthermore, when the Ca(v)3.1 T-type Ca(2+) channel expression was decreased in both endothelial cell subtypes with specific small-interfering RNA, the distension-induced expression of P-selectin decreased to levels less than that observed in static cells. We conclude that P-selectin expression on systemic venular endothelial cells contributes to a proinflammatory phenotype after mechanical stretch and can be selectively modulated by voltage-gated calcium channel inhibition.

Publication types

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

MeSH terms

  • Animals
  • Calcium Channels, T-Type / deficiency
  • Calcium Channels, T-Type / genetics
  • Calcium Channels, T-Type / metabolism
  • Cell Adhesion / drug effects
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Gene Expression Regulation / drug effects
  • In Vitro Techniques
  • Leukocytes / cytology
  • Leukocytes / drug effects
  • Male
  • Mibefradil / pharmacology
  • Mice
  • Mice, Inbred C57BL
  • Microscopy
  • P-Selectin / metabolism*
  • Pneumonia / metabolism*
  • Positive-Pressure Respiration
  • Pulmonary Veins / cytology
  • Pulmonary Veins / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Stress, Mechanical
  • Verapamil / pharmacology

Substances

  • Calcium Channels, T-Type
  • P-Selectin
  • RNA, Messenger
  • Mibefradil
  • Verapamil