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Granzyme B of cytotoxic T cells induces extramitochondrial reactive oxygen species production via caspase‐dependent NADPH oxidase activation
Author(s) -
Aguiló Juan I,
Anel Alberto,
Catalán Elena,
Sebastián Alvaro,
AcínPérez Rebeca,
Naval Javier,
Wallich Reinhard,
Simon Markus M,
Pardo Julián
Publication year - 2010
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.2010.5
Subject(s) - microbiology and biotechnology , reactive oxygen species , nadph oxidase , apocynin , biology , granzyme b , mitochondrial ros , programmed cell death , mitochondrion , cytotoxic t cell , apoptosis , chemistry , biochemistry , in vitro
Induction of reactive oxygen species (ROS) is a hallmark of granzyme B (gzmB)‐mediated pro‐apoptotic processes and target cell death. However, it is unclear to what extent the generated ROS derive from mitochondrial and/or extra‐mitochondrial sources. To clarify this point, we have produced a mutant EL4 cell line, termed EL4‐ρ 0 , which lacks mitochondrial DNA, associated with a decreased mitochondrial membrane potential and a defective ROS production through the electron transport chain of oxidative phosphorylation. When incubated with either recombinant gzmB plus streptolysin or ex vivo gzmB + cytotoxic T cells, EL4‐ρ 0 cells showed phosphatydylserine translocation, caspase 3 activation, Bak conformational change, cytochrome c release and apoptotic morphology comparable to EL4 cells. Moreover, EL4‐ρ 0 cells produced ROS at levels similar to EL4 under these conditions. GzmB‐mediated ROS production was almost totally abolished in both cell lines by the pan‐caspase inhibitor, Z‐VAD‐fmk. However, addition of apocynin, a specific inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, led to a significant reduction of ROS production and cell death only in EL4‐ρ 0 but not EL4 cells. These data suggest that gzmB‐induced cell death is accompanied by a caspase‐dependent pathway of extra‐mitochondrial ROS production, most probably through activation of NADPH oxidase.