Role of Integrin β4 in Lung Endothelial Cell Inflammatory Responses to Mechanical Stress

Sci Rep. 2015 Nov 17:5:16529. doi: 10.1038/srep16529.

Abstract

Simvastatin, an HMG-CoA reductase inhibitor, has lung vascular-protective effects that are associated with decreased agonist-induced integrin β4 (ITGB4) tyrosine phosphorylation. Accordingly, we hypothesized that endothelial cell (EC) protection by simvastatin is dependent on these effects and sought to further characterize the functional role of ITGB4 as a mediator of EC protection in the setting of excessive mechanical stretch at levels relevant to ventilator-induced lung injury (VILI). Initially, early ITGB4 tyrosine phosphorylation was confirmed in human pulmonary artery EC subjected to excessive cyclic stretch (18% CS). EC overexpression of mutant ITGB4 with specific tyrosines mutated to phenylalanine (Y1440, Y1526 Y1640, or Y1422) resulted in significantly attenuated CS-induced cytokine expression (IL6, IL-8, MCP-1, and RANTES). In addition, EC overexpression of ITGB4 constructs with specific structural deletions also resulted in significantly attenuated CS-induced inflammatory cytokine expression compared to overexpression of wildtype ITGB4. Finally, mice expressing a mutant ITGB4 lacking a cytoplasmic signaling domain were found to have attenuated lung injury after VILI-challenge (VT = 40 ml/kg, 4 h). Our results provide mechanistic insights into the anti-inflammatory properties of statins and may ultimately lead to novel strategies targeted at ITGB4 signaling to treat VILI.

Publication types

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

MeSH terms

  • Animals
  • Bronchoalveolar Lavage Fluid / chemistry
  • Cell Line
  • Cytokines / metabolism
  • Disease Models, Animal
  • Endothelial Cells / cytology
  • Endothelial Cells / metabolism
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / therapeutic use
  • Inflammation / prevention & control
  • Integrin beta4 / chemistry
  • Integrin beta4 / genetics
  • Integrin beta4 / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mutagenesis, Site-Directed
  • Permeability / drug effects
  • Phosphorylation
  • Protein Structure, Tertiary
  • Pulmonary Artery / cytology
  • Simvastatin / pharmacology
  • Simvastatin / therapeutic use
  • Stress, Mechanical*
  • Ventilator-Induced Lung Injury / metabolism
  • Ventilator-Induced Lung Injury / pathology
  • Ventilator-Induced Lung Injury / prevention & control

Substances

  • Cytokines
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Integrin beta4
  • Simvastatin