Expressed isolated integrin βI subunit cytodomain induces endothelial cell death secondary to detachment

Meriem Hasmim, Giuseppe Vassalli, Gian Carlo Alghisi, Jeannine Bamat, Lionel Ponsonnet, Grégory Bieler, Claude Bonnard, Cécile Paroz, Delphine Oguey, Curzio Rüegg*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

17 Citations (Scopus)

Abstract

Expression of isolated β integrin cytoplasmic domains in cultured endothelial cells was reported to induce cell detachment and death. To test whether cell death was the cause or the consequence of cell detachment, we expressed isolated integrin β1 cytoplasmic and transmembrane domains (CH1) in cultured human umbilical vein endothelial cells (HUVEC), and monitored detachment, viability, caspase activation and signaling. CH1 expression induced dose-dependent cell detachment. At 24 h over 90% of CH1-expressing HUVEC were detached but largely viable (>85%). No evidence of pro-caspase-8,-3, and PARP cleavage or suppression of phosphorylation of ERK, PKB and Iκ-B was observed. The caspase inhibitor z-VAD did not prevent cell detachment. At 48 h, however, CH1-expressing cells were over 50% dead. As a comparison trypsin-mediated detachment resulted in a time-dependent cell death, paralleled by caspase-3 activation and suppression of ERK, PKB and Iκ-B phosphoyrylation at 24 h or later after detachment. HUVEC stimulation with agents that strengthen integrin-mediated adhesion (i.e. PMA, the Src inhibitor PP2 and COMP-Ang1) did not prevent CH1-induced detachment. Expression of CH1 in rat carotid artery endothelial cells in vivo caused endothelial cell detachment and increased nuclear DNA fragmentation among detached cells. A construct lacking the integrin cytoplasmic domain (CH2) had no effect on adhesion and cell viability in vitro and in vivo. These results demonstrate that isolated β1 cytoplasmic domain expression induces caspase-independent detachment of viable endothelial cells and that death is secondary to detachment (i.e. anoikis). They also reveal an essential role for integrins in the adhesion and survival of quiescent endothelial cells in vivo.

Original languageEnglish
Pages (from-to)1060-1070
Number of pages11
JournalThrombosis and Haemostasis
Volume94
Issue number5
DOIs
Publication statusPublished - Nov 2005
Externally publishedYes

Keywords

  • Adhesion receptors/integrins
  • Cell-matrix interactions
  • Endothelial cells
  • Gene transfer

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