Effet des angiopoïétines sur la survie des neutrophiles
We reported the expression of angiopoietin receptor Tie2 on the surface of human neutrophils.  In addition, we reported that Ang1 and Ang2 are both capable to promote pro-inflammatory activities in neutrophils, namely their adhesion onto endothelial cells (ECs) and platelet-activating factor (PAF) synthesis.  PAF is known to promote pro-survival activity on neutrophils and since both angiopoietins can modulate ECs viability, we addressed whether Ang1 and/or Ang2 could modulate neutrophil viability.  Human neutrophils were isolated from blood of healthy volunteers in accordance with the guidelines of the Montreal Heart Institute’s ethical committee.  Neutrophil viability was assessed by flow cytometry using apoptotic and necrotic markers. Treatment with anti-apoptotic mediators such as interleukin 8 (IL-8; 25 nM) and PAF (100 nM) increased neutrophil basal viability by 34 and 27%, respectively.  In addition, treatment with Ang1 (1 pM – 10 nM) increased neutrophil viability by up to 35%, while Ang2 had no effect.  Combination of IL-8 or PAF with Ang1 (10 nM) provided an additive effect on neutrophil viability and further increased viability by 56 and 60%, respectively.  Pretreatment of the neutrophils with blocking anti-IL-8 antibodies inhibited the anti-apoptotic effect of IL-8 and Ang1 by 92 and 80%, respectively.  In summary, our data are the first one to report Ang1 pro-survival activity on neutrophils, which is mainly driven through IL-8 release.
interleukine-8 inflammation angiopoietins interleukin-8 neutrophil viability apoptosis inflammation