Influence of duration of focal cerebral ischemia and neuronal nitric oxide synthase on translocation of apoptosis-inducing factor to the nucleus.
Translocation of apoptosis-inducing factor (AIF) from the mitochondria to the nucleus can play a major role in neuronal death elicited by oxidant stress. The time course of nuclear translocation of AIF after experimental stroke may vary with the severity of injury and may be accelerated by oxidant stress associated with reperfusion and nitric oxide (NO) production. Western immunoblots of AIF on nuclear fractions of ischemic hemisphere of male mice showed no significant increase with 1 h of middle cerebral artery occlusion and no reperfusion, whereas increases were detectable after 6 and 24 h of permanent ischemia. However, as little as 20 min of reperfusion after 1 h of middle cerebral artery occlusion resulted in an increase in nuclear AIF coincident with an increase in poly(ADP-ribose) polymer (PAR) formation. Further nuclear AIF accumulation was seen at 6 and 24 h of reperfusion. In contrast, 20 min of reperfusion after 2 h of occlusion did not increase nuclear AIF. In this case, nuclear AIF became detectable at 6 and 24 h of reperfusion. With brief occlusion of 30 min duration, nuclear AIF remained undetectable at both 20 min and 6 h and became evident only after 24 h of reperfusion. Inhibition of neuronal NO synthase attenuated formation of PAR and nuclear AIF accumulation. Gene deletion of neuronal NO synthase also attenuated nuclear AIF accumulation. Therefore, reperfusion accelerates AIF translocation to the nucleus when focal ischemia is of moderate duration (1 h), but is markedly delayed after brief ischemia (30 min). Nuclear translocation of AIF eventually occurs with prolonged focal ischemia with or without reperfusion. Neuronally-derived NO is a major factor contributing to nuclear AIF accumulation after stroke.
Li
X
X
Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins Medical Institutions, The Johns Hopkins University, 600 North Wolfe Street, Blalock 1404, Baltimore, MD 21287, USA.
Nemoto
M
M
Xu
Z
Z
Yu
S-W
SW
Shimoji
M
M
Andrabi
S A
SA
Haince
J-F
JF
Poirier
G G
GG
Dawson
T M
TM
Dawson
V L
VL
Koehler
R C
RC
D000818:Animals; D051033:Apoptosis Inducing Factor / Q000378:metabolism*; D001522:Behavior, Animal / Q000502:physiology; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017353:Gene Deletion; D007191:Indazoles / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology / Q000523:psychology; D002546:Ischemic Attack, Transient / Q000473:pathology* / Q000523:psychology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000201:enzymology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism; D021381:Protein Transport; D015427:Reperfusion Injury / Q000473:pathology / Q000523:psychology; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors
D051033:Apoptosis Inducing Factor; D004791:Enzyme Inhibitors; D007191:Indazoles; D011064:Poly Adenosine Diphosphate Ribose; D052248:Nitric Oxide Synthase Type I; C080122:7-nitroindazole