scholarly journals Endonuclease G does not play an obligatory role in poly(ADP-ribose) polymerase-dependent cell death after transient focal cerebral ischemia

2010 ◽  
Vol 299 (1) ◽  
pp. R215-R221 ◽  
Author(s):  
Zhenfeng Xu ◽  
Jian Zhang ◽  
Karen K. David ◽  
Zeng-Jin Yang ◽  
Xiaoling Li ◽  
...  
Keyword(s):  
Cell Death ◽  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Nuclear Translocation ◽  
Focal Cerebral Ischemia ◽  
Infarct Volume ◽  
Wild Type ◽  
Endonuclease G ◽  
Transient Focal Cerebral Ischemia ◽  
Apoptosis Inducing Factor

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.

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 ◽  
...  
Keyword(s):  
Cell Death ◽  
Cerebral Ischemia ◽  
Cytochrome C ◽  
Nuclear Translocation ◽  
Focal Cerebral Ischemia ◽  
Mitochondrial Protein ◽  
Neuronal Cell ◽  
Experimental Stroke ◽  
Cytochrome C Release ◽  
Apoptosis Inducing Factor

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.

scholarly journals Oxidative Stress Transiently Decreases the IKK Complex (IKKα, β, and γ), an Upstream Component of NF-κB Signaling, after Transient Focal Cerebral Ischemia in Mice

2005 ◽  
Vol 25 (10) ◽  
pp. 1301-1311 ◽  
Author(s):  
Yun S Song ◽  
Yong-Sun Lee ◽  
Pak H Chan
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Dna Array ◽  
Wild Type ◽  
Iκb Kinase ◽  
Transient Focal Cerebral Ischemia ◽  
Ikk Complex ◽  
In The Wild

Nuclear factor-κB (NF-κB) has a central role in coordinating the expression of a wide variety of genes that control cerebral ischemia. Although there has been intense research on NF-κB, its mechanisms in the ischemic brain have not been clearly elucidated. We investigated the temporal profile of NF-κB-related genes using a complementary DNA array method in wild-type mice and human copper/zinc-superoxide dismutase transgenic (SOD1 Tg) mice that had low-level reactive oxygen species (ROS) by scavenging superoxide. Our DNA array showed that IκB kinase (IKK) complex (IKKα, β, and γ) mRNA in the wild-type mice was decreased as early as 1 h after reperfusion, after 30 mins of transient focal cerebral ischemia (tFCI). In contrast, tFCI in the SOD1 Tg mice caused an increase in the IKK complex. The IKK complex protein levels were also drastically decreased at 1 h in the wild-type mice, but did not change in the SOD1 Tg mice throughout the 7 days. Electrophoretic mobility shift assay revealed activation of NF-κB DNA binding after tFCI in the wild-type mice. Nuclear factor-κB activation occurred at the same time, as did the phosphorylation and degradation of the inhibitory protein κBα. However, SOD1 prevented NF-κB activation, and phosphorylation and degradation of IκBα after tFCI. Superoxide production and ubiquitinated protein in the SOD1 Tg mice were also lower than in the wild-type mice after tFCI. These results suggest that ROS are implicated in transient downregulation of IKKα, β, and γ in cerebral ischemia.

scholarly journals Oxidative Stress Increases Phosphorylation of IκB Kinase-α by Enhancing NF-κB-Inducing Kinase after Transient Focal Cerebral Ischemia

2010 ◽  
Vol 30 (7) ◽  
pp. 1265-1274 ◽  
Author(s):  
Yun Seon Song ◽  
Min-Soo Kim ◽  
Hyun-Ae Kim ◽  
Bo-In Jung ◽  
Jiwon Yang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Nuclear Factor Κb ◽  
Nuclear Accumulation ◽  
Brain Endothelial Cells ◽  
Iκb Kinase ◽  
Transient Focal Cerebral Ischemia ◽  
Mouse Brain Endothelial Cells

The IκB kinase (IKK) complex is a central component in the classic activation of the nuclear factor-κB (NF-κB) pathway. It has been reported to function in physiologic responses, including cell death and inflammation. We have shown that IKK is regulated by oxidative status after transient focal cerebral ischemia (tFCI) in mice. However, the mechanism by which oxidative stress influences IKKs after tFCI is largely unknown. Nuclear accumulation and phosphorylation of IKKα (pIKKα) were observed 1 h after 30 mins of tFCI in mice. In copper/zinc-superoxide dismutase knockout mice, levels of NF-κB-inducing kinase (NIK) (an upstream kinase of IKKα), pIKKα, and phosphorylation of histone H3 (pH3) on Ser10 were increased after tFCI and were higher than in wild-type mice. Immunohistochemistry showed nuclear accumulation and pIKKα in mouse brain endothelial cells after tFCI. Nuclear factor-κB-inducing kinase was increased, and it enhanced pH3 by inducing pIKKα after oxygen–glucose deprivation (OGD) in mouse brain endothelial cells. Both NIK and pH3 interactions with IKKα were confirmed by coimmunoprecipitation. Treatment with IKKα small interfering RNA significantly reduced cell death after OGD. These results suggest that augmentation of NIK, IKKα, and pH3 in response to oxidative stress is involved in cell death after cerebral ischemia (or stroke).

scholarly journals Transcriptomic characterization of microglia activation in a rat model of ischemic stroke

2020 ◽  
Vol 40 (1_suppl) ◽  
pp. S34-S48
Author(s):  
Wenjun Deng ◽  
Emiri Mandeville ◽  
Yasukazu Terasaki ◽  
Wenlu Li ◽  
Julie Holder ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Phenotypic Diversity ◽  
Focal Cerebral Ischemia ◽  
Wide Spectrum ◽  
Spontaneously Hypertensive ◽  
Transient Focal Cerebral Ischemia ◽  
Microglial Response ◽  
Whole Transcriptome

Microglia are key regulators of inflammatory response after stroke and brain injury. To better understand activation of microglia as well as their phenotypic diversity after ischemic stroke, we profiled the transcriptome of microglia after 75 min transient focal cerebral ischemia in 3-month- and 12-month-old male spontaneously hypertensive rats. Microglia were isolated from the brains by FACS sorting on days 3 and 14 after cerebral ischemia. GeneChip Rat 1.0ST microarray was used to profile the whole transcriptome of sorted microglia. We identified an evolving and complex pattern of activation from 3 to 14 days after stroke onset. M2-like patterns were extensively and persistently upregulated over time. M1-like patterns were only mildly upregulated, mostly at day 14. Younger 3-month-old brains showed a larger microglial response in both pro- and anti-inflammatory pathways, compared to older 12-month-old brains. Importantly, our data revealed that after stroke, most microglia are activated towards a wide spectrum of novel polarization states beyond the standard M1/M2 dichotomy, especially in pathways related to TLR2 and dietary fatty acid signaling. Finally, classes of transcription factors that might potentially regulate microglial activation were identified. These findings should provide a comprehensive database for dissecting microglial mechanisms and pursuing neuroinflammation targets for acute ischemic stroke.

scholarly journals Augmentation of poly(ADP-ribose) polymerase-dependent neuronal cell death by acidosis

2016 ◽  
Vol 37 (6) ◽  
pp. 1982-1993 ◽  
Author(s):  
Jian Zhang ◽  
Xiaoling Li ◽  
Herman Kwansa ◽  
Yun Tai Kim ◽  
Liye Yi ◽  
...  
Keyword(s):  
Cell Death ◽  
Ion Channel ◽  
Focal Cerebral Ischemia ◽  
Infarct Volume ◽  
Neuronal Cell ◽  
Neuronal Cultures ◽  
Primary Neuronal Cultures ◽  
Tissue Acidosis ◽  
Nuclear Apoptosis ◽  
Apoptosis Inducing Factor

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.

VWF-Cleaving Protease ADAMTS13 Reduces Brain Injury Following Ischemic Stroke in Mice: Essential Role for VWF in Stroke

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 259-259
Author(s):  
Bing-Qiao Zhao ◽  
Anil kumar Chauhan ◽  
Ian S. Patten ◽  
Michael Dockal ◽  
Friedrich Scheiflinger ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Essential Role ◽  
Focal Cerebral Ischemia ◽  
Infarct Volume ◽  
Recombinant Tissue Plasminogen Activator ◽  
Protective Role ◽  
Artery Occlusion ◽  
Type I ◽  
Deficient Mice

Abstract Ischemic stroke is the second leading cause of death and disability. The only approved therapy available is recombinant tissue plasminogen activator (tPA), but its use remains limited. Therefore, there is a need for an alternative drug. Platelets and their adhesion receptors play a crucial role in modulating infarct size during ischemic stroke. ADAMTS13 (A Disintegrin-like And Metalloprotease with Thrombospondin type I repeats-13) is a plasma metalloprotease that cleaves von Willebrand factor (VWF) an important adhesion molecule for platelets at sites of vascular injury. In patients, an increase in circulating levels of VWF and a decrease in ADAMTS13 activity are considered risk factors for ischemic stroke. By using genetically-modified mice we have previously shown that ADAMTS13 down regulates both thrombosis and inflammation and recombinant human ADAMTS13 down regulates platelet thrombi in injured arterioles. All these processes were dependent on VWF. We therefore hypothesize that ADAMTS13 has a protective role after ischemic stroke. In this study, we show that VWF deficiency or VWF heterozygosity in mice reduces infarct volume by two-fold after focal cerebral ischemia compared to wild-type (WT) in the middle cerebral artery occlusion (MCAO) stroke model. Furthermore, infusion of recombinant human VWF in WT mice not only accelerates thrombosis in the ferric-chloride injured artery model, but also increases infarct volume compared to vehicle-treated controls. These findings suggest an essential role of VWF in modulating infarction after stroke. We also show that ADAMTS13 deficiency in mice results in approximately 20% larger infarcts after cerebral ischemia compared to WT. The larger infarcts observed in ADAMTS13 deficient mice were due to VWF because mice deficient in both ADAMTS13 and VWF had infarct sizes similar to VWF deficient mice. Importantly, infusion of r-human ADAMTS13 immediately before reperfusion (two hour after occlusion) significantly reduced infarct volume (106.2 ± 9.7 mm3 vs 75.8 ± 6.9 mm3, P<0.05). Of note, we observed that ADAMTS13 protein was induced in the ischemic penumbra region of brain after ischemic stroke. Our findings reveal an important role for VWF in modulating infarct volume after ischemic stroke. In addition, recombinant-ADAMTS13 could become a new therapeutic agent for stroke therapy.

scholarly journals Contributions of poly(ADP-ribose) polymerase-1 and -2 to nuclear translocation of apoptosis-inducing factor and injury from focal cerebral ischemia

2010 ◽  
Vol 113 (4) ◽  
pp. 1012-1022 ◽  
Author(s):  
Xiaoling Li ◽  
Judith A. Klaus ◽  
Jian Zhang ◽  
Zhenfeng Xu ◽  
Kathleen K. Kibler ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Nuclear Translocation ◽  
Focal Cerebral Ischemia ◽  
Apoptosis Inducing Factor
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