Protection from apoptosis in human neutrophils is determined by the
surface of adhesion.
Ginis, Irene, and Douglas V. Faller.
Cancer Research Center, and Departments of Medicine, Biochemistry,
Pediatrics, Microbiology, Pathology and Laboratory Medicine, Boston
University School of Medicine, Boston, MA 02118, USA
APStracts 3:0261C, 1996.
Recent work suggests that various neutrophil agonists affect the rate
of apoptosis in these cells. Based on these observations, we
hypothesized that signals triggered in neutrophils via their adhesion
receptors might also modify their lifespan. This hypothesis has been
tested using human neutrophils adherent to tissue culture plastic,
either untreated, or coated with extracellular matrix (ECM) proteins
or with monolayers of human umbilical vein endothelial cells (HUVEC).
To detect and quantitate apoptotic changes in adherent cells, we
developed a microtiter plate assay using a cell-permeable DNA-binding
fluorescent dye, Hoechst 33342. Using this assay, it was demonstrated
that: 1) the number of apoptotic cells among neutrophils adherent to
plastic after 6-20 hours of incubation was significantly lower than
among neutrophils adherent to the ECM proteins, fibronectin or
laminin; 2) adhesion to IL-1- activated endothelial cells delayed
apoptosis, while adhesion to non-activated endothelium accelerated
neutrophil death; 3) MAb directed against ICAM-1, or against the
common beta2-chain of the leukocyte integrins, abolished the
protective effect of IL-1-activated endothelial cells on apoptosis of
adherent neutrophils. These results suggest that the lifespan of
adherent neutrophils depends on the activating signals triggered by
the surface of adhesion.
Received 22 January 1996; accepted in final form 15 July 1996.
APS Manuscript Number C45-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996