Premium
Mechanism of 3‐nitropropionic acid‐induced membrane permeability transition of isolated mitochondria and its suppression by L ‐carnitine
Author(s) -
Nishimura Makoto,
Okimura Yuya,
Fujita Hirofumi,
Yano Hiromi,
Lee Jintae,
Suzaki Etsuko,
Inoue Masayasu,
Utsumi Kozo,
Sasaki Junzo
Publication year - 2008
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1521
Subject(s) - mitochondrion , mitochondrial permeability transition pore , programmed cell death , oxidative phosphorylation , phospholipase a2 , inner mitochondrial membrane , biochemistry , neuroprotection , biology , microbiology and biotechnology , chemistry , apoptosis , pharmacology , enzyme
3‐Nitropropionic acid (3NP) functions as an irreversible inhibitor of succinic acid dehydrogenase (complex II) and induces neuronal disorders in rats similar to those in patients with Huntington's disease. It is well known that L ‐carnitine (LC), a carrier of long chain fatty acid into the mitochondrial matrix, attenuates the neuronal degeneration in 3NP‐treated rats. From these findings it has been suggested that 3NP induces certain neuronal cell death through mitochondrial dysfunction and that LC preserves the neurons against the dysfunction of mitochondria caused by 3NP. However, the detailed mechanism of cell death by 3NP and the protective actions of LC against the mitochondrial dysfunction have not been fully elucidated yet. Thus, we studied the molecular mechanism of the effects of 3NP and LC on isolated rat liver mitochondria. 3NP inhibited succinate respiration and the decreased respiratory control ratio of isolated mitochondria without affecting oxidative phosphorylation. 3NP induced a membrane permeability transition (MPT), which plays an important role in the mechanism of apoptotic cell death. 3NP stimulated Ca 2+ release from mitochondria, decreased membrane potential, induced mitochondrial swelling, and stimulated cytochrome c release from mitochondria. 3NP‐induced swelling was suppressed by bovine serum albumin, inhibitors of phospholipase A 2 and by an inhibitor of classic MPT, cyclosporin A. Furthermore, LC suppressed the changes brought about by 3NP in mitochondrial functions in the presence of ATP. These results suggest that MPT underlies the mechanism of 3NP‐induced cell death, and that LC attenuates mitochondrial MPT by decreasing long chain fatty acids generated by phospholipase A 2 . Copyright © 2008 John Wiley & Sons, Ltd.