title: Nitric oxide-mediated apoptosis of neutrophils through caspase-8 and caspase-3-dependent mechanism.
abstract: 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.
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Megha
authors: M
authors: Dubey
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Sheela
authors: S
authors: Nagarkoti
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Deepika
authors: D
authors: Awasthi
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Abhishek K
authors: AK
authors: Singh
authors: Department of Transfusion Medicine, King George's Medical University, Lucknow, India.
authors: Tulika
authors: T
authors: Chandra
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: J
authors: J
authors: Kumaravelu
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Manoj K
authors: MK
authors: Barthwal
authors: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, India.
authors: Madhu
authors: M
authors: Dikshit
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000166:cytology; D053148:Caspase 3 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D053148:Caspase 3; D053181:Caspase 8