Cigarette smoke-induced CXCR3 receptor up-regulation mediates endothelial apoptosis

Am J Respir Cell Mol Biol. 2012 Dec;47(6):807-14. doi: 10.1165/rcmb.2012-0132OC. Epub 2012 Aug 30.

Abstract

Endothelial monocyte-activating polypeptide II (EMAP II) and interferon-inducible protein (IP)-10 are proinflammatory mediators, which in addition to their chemokine activities, selectively induce apoptosis in endothelial cells and are up-regulated in the lungs of cigarette smoke-exposed humans. Previously, we showed that EMAP II is an essential mediator of cigarette smoke-induced lung emphysema in mice linking endothelial cell apoptosis with inflammation. Here we addressed the role of the CXCR3 receptor in EMAP II-induced and IP-10-induced apoptosis in endothelial cells and its regulation by cigarette smoke. We found that both neutralizing antibodies and small inhibitory RNA to CXCR3 abrogated EMAP II-induced and IP-10-induced endothelial caspase-3 activation and DNA fragmentation. CXCR3 receptor surface expression in human lung microvascular endothelial cells and in lung tissue endothelium was up-regulated by exposure to cigarette smoke. In tissue culture conditions, EMAP II-induced and IP-10-induced apoptosis was enhanced by preincubation with cigarette smoke extract. Interestingly, serum starvation also induced CXCR3 up-regulation and enhanced EMAP II-induced endothelial apoptosis. Signal transduction via p38 mitogen-activated protein kinase activation was essential for CXCR3-induced cell death, but not for CXCR3 receptor up-regulation by cigarette smoke. In turn, protein nitration was required for CXCR3 receptor up-regulation by cigarette smoke and consequently for subsequent CXCR3-induced cell death. In conclusion, the concerted up-regulation of proinflammatory EMAP II, IP-10, and CXCR3 by cigarette smoke could sustain a cascade of cell death that may promote the alveolar tissue loss noted in human emphysema.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis*
  • Cells, Cultured
  • Chemokine CXCL10 / pharmacology
  • Culture Media, Serum-Free
  • Cytokines / pharmacology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Endothelial Cells / physiology
  • Endothelium, Vascular / cytology
  • Female
  • Humans
  • Lung / cytology
  • Lung / drug effects
  • MAP Kinase Signaling System
  • Mice
  • Mice, Inbred C57BL
  • Microvessels / cytology
  • Neoplasm Proteins / pharmacology
  • Nicotiana / chemistry*
  • Plant Extracts / pharmacology*
  • RNA-Binding Proteins / pharmacology
  • Receptors, CXCR3 / genetics
  • Receptors, CXCR3 / metabolism*
  • Smoke*
  • Tyrosine / analogs & derivatives
  • Tyrosine / metabolism
  • Up-Regulation / drug effects*

Substances

  • CXCR3 protein, human
  • Chemokine CXCL10
  • Culture Media, Serum-Free
  • Cytokines
  • Neoplasm Proteins
  • Plant Extracts
  • RNA-Binding Proteins
  • Receptors, CXCR3
  • Smoke
  • small inducible cytokine subfamily E, member 1
  • 3-nitrotyrosine
  • Tyrosine