scholarly journals Nuclear Translocation of Apoptosis-Inducing Factor after Focal Cerebral Ischemia

2004 ◽  
Vol 24 (4) ◽  
pp. 458-466 ◽  
Author(s):  
Nikolaus Plesnila ◽  
Changlian Zhu ◽  
Carsten Culmsee ◽  
Moritz Gröger ◽  
Michael A. Moskowitz ◽  
...  

Signaling cascades associated with apoptosis contribute to cell death after focal cerebral ischemia. Cytochrome c release from mitochondria and the subsequent activation of caspases 9 and 3 are critical steps. Recently, a novel mitochondrial protein, apoptosis-inducing factor (AIF), has been implicated in caspase-independent programmed cell death following its translocation to the nucleus. We, therefore, addressed the question whether AIF also plays a role in cell death after focal cerebral ischemia. We detected AIF relocation from mitochondria to nucleus in primary cultured rat neurons 4 and 8 hours after 4 hours of oxygen/glucose deprivation. In ischemic mouse brain, AIF was detected within the nucleus 1 hour after reperfusion after 45 minutes occlusion of the middle cerebral artery. AIF translocation preceded cell death, occurred before or at the time when cytochrome c was released from mitochondria, and was evident within cells showing apoptosis-related DNA fragmentation. From these findings, we infer that AIF may be involved in neuronal cell death after focal cerebral ischemia and that caspase-independent signaling pathways downstream of mitochondria may play a role in apoptotic-like cell death after experimental stroke.

2010 ◽  
Vol 299 (1) ◽  
pp. R215-R221 ◽  
Author(s):  
Zhenfeng Xu ◽  
Jian Zhang ◽  
Karen K. David ◽  
Zeng-Jin Yang ◽  
Xiaoling Li ◽  
...  

Activation of poly(ADP-ribose) polymerase (PARP) and subsequent translocation of apoptosis-inducing factor contribute to caspase-independent neuronal injury from N-methyl-d-aspartate, oxygen-glucose deprivation, and ischemic stroke. Some studies have implicated endonuclease G in the DNA fragmentation associated with caspase-independent cell death. Here, we compared wild-type and endonuclease G null mice to investigate whether endonuclease G plays a role in the PARP-dependent injury that results from transient focal cerebral ischemia. Latex casts did not reveal differences in the cerebral arterial distribution territory or posterior communicating arterial diameter, and the decrease in laser-Doppler flux during middle cerebral artery occlusion was similar in wild-type and endonuclease G null mice. After 90 min of occlusion and 1 day of reperfusion, similar degrees of nuclear translocation of apoptosis-inducing factor and DNA degradation were evident in male wild-type and null mice. At 3 days of reperfusion, infarct volume and neurological deficit scores were not different between male wild-type and endonuclease G null mice or between female wild-type and endonuclease G null mice. These data demonstrate that endonuclease G is not required for the pathogenesis of transient focal ischemia in either male or female mice. Treatment with a PARP inhibitor decreased infarct volume and deficit scores equivalently in male wild-type and endonuclease G null mice, indicating that the injury in endonuclease G null mice remains dependent on PARP. Thus endonuclease G is not obligatory for executing PARP-dependent injury during ischemic stroke.


2001 ◽  
Vol 21 (5) ◽  
pp. 557-567 ◽  
Author(s):  
Nobuo Noshita ◽  
Taku Sugawara ◽  
Miki Fujimura ◽  
Yuiko Morita-Fujimura ◽  
Pak H. Chan

Release of cytochrome c from mitochondria to cytosol is a critical step in the mitochondrial-dependent signaling pathways of apoptosis. The authors have reported that manganese superoxide dismutase (Mn-SOD) attenuated cytochrome c release and apoptotic cell death after focal cerebral ischemia (FCI). To investigate downstream to the cytochrome c-dependent pathway, the authors examined caspase-9 activation after transient FCI by immunohistochemistry and Western blotting in both wild-type and Sod2 −/+ mice. Mice were subjected to 60 minutes of middle cerebral artery occlusion followed by 1, 2, 4, or 24 hours of reperfusion. Two hours after reperfusion, cytochrome c and caspase-9 were observed in the cytosol and significantly increased in Sod2 −/+ mutants compared with wild-type mice as shown by Western blotting. Immunofluorescent double labeling for cytochrome c and caspase-9 showed cytosolic cytochrome c 1 hour after transient FCI. Cleaved caspase-9 first appeared in the cytosol at 2 hours and colocalized with cytochrome c. Terminal deoxynucleotidyl transferase-mediated uridine 5′-triphosphate-biotin nick and labeling (TUNEL) showed significant increase of positive cells in Sod2 −/+ mice compared with the wild-type in the cortex, but not in the caudate putamen. The current study revealed Mn-SOD might affect cytochrome c translocation and downstream caspase activation in the mitochondrial-dependent cell death pathway after transient FCI.


1998 ◽  
Vol 18 (11) ◽  
pp. 1239-1247 ◽  
Author(s):  
Miki Fujimura ◽  
Yuiko Morita-Fujimura ◽  
Kensuke Murakami ◽  
Makoto Kawase ◽  
Pak H. Chan

Recent in vitro cell-free studies have shown that cytochrome c release from mitochondria is a critical step in the apoptotic process. The present study examined the expression of cytochrome c protein after transient focal cerebral ischemia in rats, in which apoptosis was assumed to contribute to the expansion of the ischemic lesion. In situ labeling of DNA breaks in frozen sections after 90 minutes of middle cerebral artery (MCA) occlusion showed a significant number of striatal and cortical neurons, which were maximized at 24 hours after ischemia, exhibiting chromatin condensation, nuclear segmentation, and apoptotic bodies. Cytosolic localization of cytochrome c was detected immunohistochemically in the ischemic area as early as 4 hours after 90 minutes of MCA occlusion. Western blot analysis of the cytosolic fraction revealed a strong single 15-kDa band, characteristic of cytochrome c, only in the samples from the ischemic hemisphere. Western blot analysis of the mitochondrial fraction showed a significant amount of mitochondrial cytochrome c in nonischemic brain, which was decreased in ischemic brain 24 hours after ischemia. These results provide the first evidence that cytochrome c is being released from mitochondria to the cytosol after transient focal ischemia. Although further evaluation is necessary to elucidate its correlation with DNA fragmentation, our results suggest the possibility that cytochrome c release may play a role in DNA-damaged neuronal cell death after transient focal cerebral ischemia in rats.


Stroke ◽  
2001 ◽  
Vol 32 (8) ◽  
pp. 1906-1911 ◽  
Author(s):  
Shobu Namura ◽  
Izumi Nagata ◽  
Shinya Takami ◽  
Hiroyuki Masayasu ◽  
Haruhiko Kikuchi

2016 ◽  
Vol 37 (6) ◽  
pp. 1982-1993 ◽  
Author(s):  
Jian Zhang ◽  
Xiaoling Li ◽  
Herman Kwansa ◽  
Yun Tai Kim ◽  
Liye Yi ◽  
...  

Tissue acidosis is a key component of cerebral ischemic injury, but its influence on cell death signaling pathways is not well defined. One such pathway is parthanatos, in which oxidative damage to DNA results in activation of poly(ADP-ribose) polymerase and generation of poly(ADP-ribose) polymers that trigger release of mitochondrial apoptosis-inducing factor. In primary neuronal cultures, we first investigated whether acidosis per sé is capable of augmenting parthanatos signaling initiated pharmacologically with the DNA alkylating agent, N-methyl- N′-nitro- N-nitrosoguanidine. Exposure of neurons to medium at pH 6.2 for 4 h after N-methyl- N′-nitro- N-nitrosoguanidine washout increased intracellular calcium and augmented the N-methyl- N′-nitro- N-nitrosoguanidine-evoked increase in poly(ADP-ribose) polymers, nuclear apoptosis-inducing factor , and cell death. The augmented nuclear apoptosis-inducing factor and cell death were blocked by the acid-sensitive ion channel-1a inhibitor, psalmotoxin. In vivo, acute hyperglycemia during transient focal cerebral ischemia augmented tissue acidosis, poly(ADP-ribose) polymers formation, and nuclear apoptosis-inducing factor , which was attenuated by a poly(ADP-ribose) polymerase inhibitor. Infarct volume from hyperglycemic ischemia was decreased in poly(ADP-ribose) polymerase 1-null mice. Collectively, these results demonstrate that acidosis can directly amplify neuronal parthanatos in the absence of ischemia through acid-sensitive ion channel-1a . The results further support parthanatos as one of the mechanisms by which ischemia-associated tissue acidosis augments cell death.


2010 ◽  
Vol 113 (4) ◽  
pp. 1012-1022 ◽  
Author(s):  
Xiaoling Li ◽  
Judith A. Klaus ◽  
Jian Zhang ◽  
Zhenfeng Xu ◽  
Kathleen K. Kibler ◽  
...  

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