| |
|
|
|
|
|
|
|||
|
Blood, 1 September 2008, Vol. 112, No. 5, pp. 2046-2054. Prepublished online as a Blood First Edition Paper on June 4, 2008; DOI 10.1182/blood-2008-04-149575.
PHAGOCYTES Granulocyte colony-stimulating factor delays neutrophil apoptosis by inhibition of calpains upstream of caspase-31 Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research and Phagocytes, Amsterdam; and 2 Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands Neutrophils have a very short life span and undergo apoptosis within 24 hours after leaving the bone marrow. Granulocyte colony-stimulating factor (G-CSF) is essential for the recruitment of fresh neutrophils from the bone marrow but also delays apoptosis of mature neutrophils. To determine the mechanism by which G-CSF inhibits neutrophil apoptosis, the kinetics of neutrophil apoptosis during 24 hours in the absence or presence of G-CSF were analyzed in vitro. G-CSF delayed neutrophil apoptosis for approximately 12 hours and inhibited caspase-9 and -3 activation, but had virtually no effect on caspase-8 and little effect on the release of proapoptotic proteins from the mitochondria. However, G-CSF strongly inhibited the activation of calcium-dependent cysteine proteases calpains, upstream of caspase-3, via apparent control of Ca2+-influx. Calpain inhibition resulted in the stabilization of the X-linked inhibitor of apoptosis (XIAP) and hence inhibited caspase-9 and -3 in human neutrophils. Thus, neutrophil apoptosis is controlled by G-CSF after initial activation of caspase-8 and mitochondrial permeabilization by the control of postmitochondrial calpain activity.
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Copyright © 2008 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||