Open AccessNitric oxide-mediated apoptosis of neutrophils through caspase-8 and caspase-3-dependent mechanism
Author(s) -
Megha Dubey,
Sheela Nagarkoti,
Deepika Awasthi,
Abhishek Kumar Singh,
Tulika Chandra,
Kumaravelu Jagavelu,
Manoj Kumar Barthwal,
Madhu Dikshit
Publication year - 2016
Publication title -
cell death and disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.482
H-Index - 111
ISSN - 2041-4889
DOI - 10.1038/cddis.2016.248
Subject(s) - apoptosis , microbiology and biotechnology , caspase , reactive oxygen species , nitric oxide synthase , mitochondrion , apoptosis inducing factor , caspase 3 , intrinsic apoptosis , mitochondrial ros , biology , nitric oxide , programmed cell death , chemistry , biochemistry , endocrinology
Neutrophils play an indispensable role in killing of invading pathogens by enhancing reactive oxygen species (ROS) and NO generation, and subsequently undergoing apoptosis. Unlike ROS/NOX2, role of NO/NOS still remains undefined in the apoptosis of neutrophils (PMNs) and the present study attempts to decipher the importance of NO/NOS in the neutrophil apoptosis. Prolonged treatment of human PMNs or mice bone marrow derived neutrophils (BMDN) with NO led to enhanced ROS generation, caspase-8/caspase-3 cleavage, reduced mitochondrial membrane potential and finally cellular apoptosis. NO-induced ROS generation led to caspase-8 deglutathionylation and activation, which subsequently activated mitochondrial death pathway via BID (Bcl-2 family protein) cleavage. NO-mediated augmentation of caspase-8 and BID cleavage was significantly prevented in BMDN from neutrophil cytosolic factor-1 (NCF-1) knockout (KO) mice, implying the involvement of NOX2 in NO-induced apoptosis of PMNs. Furthermore, ROS, NO generation and inducible nitric oxide synthase (iNOS) expression were enhanced in a time-dependent manner in human PMNs and mice BMDN undergoing spontaneous apoptosis. Pharmacological and genetic ablation of iNOS in human PMNs and mice BMDN significantly reduced the levels of apoptosis. Impaired apoptosis of BMDN from iNOS KO mice was due to reduced caspase-8 activity which subsequently prevented caspase-3 and -9 activation. Altogether, our results suggest a crucial role of NO/iNOS in neutrophil apoptosis via enhanced ROS generation and caspase-8 mediated activation of mitochondrial death pathway.