scholarly journals Biphasic Cytochrome c Release After Transient Global Ischemia and its Inhibition by Hypothermia

2005 ◽  
Vol 25 (9) ◽  
pp. 1119-1129 ◽  
Author(s):  
Heng Zhao ◽  
Midori A Yenari ◽  
Danye Cheng ◽  
Robert M Sapolsky ◽  
Gary K Steinberg

Hypothermia is effective in preventing ischemic damage. A caspase-dependent apoptotic pathway is involved in ischemic damage, but how hypothermia inhibits this pathway after global cerebral ischemia has not been well explored. It was determined whether hypothermia protects the brain by altering cytochrome c release and caspase activity. Cerebral ischemia was produced by two-vessel occlusion plus hypotension for 10 mins. Body temperature in hypothermic animals was reduced to 33°C before ischemia onset and maintained for 3 h after reperfusion. Western blots of subcellular fractions revealed biphasic cytosolic cytochrome c release, with an initial peak at about 5 h after ischemia, which decreased at 12 to 24 h, and a second, larger peak at 48 h. Caspase-3 and −9 activity increased at 12 and 24 h. A caspase inhibitor, Z-DEVD-FMK, administered 5 and 24 h after ischemia onset, protected hippocampal CA1 neurons from injury and blocked the second cytochrome c peak, suggesting that caspases mediate this second phase. Hypothermia (33°C), which prevented CA1 injury, did not inhibit cytochrome c release at 5 h, but reduced cytochrome c release at 48 h. Caspase-3 and −9 activity was markedly attenuated by hypothermia at 12 and 24 h. Thus, biphasic cytochrome c release occurs after transient global ischemia and mild hypothermia protects against ischemic damage by blocking the second phase of cytochrome c release, possibly by blocking caspase activity.

2002 ◽  
Vol 96 (Sup 2) ◽  
pp. A800
Author(s):  
Baiping Lei ◽  
Susanna Popp ◽  
Christine Capuano-Waters ◽  
James E. Cottrell ◽  
Ira S. Kass

2007 ◽  
Vol 27 (8) ◽  
pp. 1463-1475 ◽  
Author(s):  
Takayoshi Shimohata ◽  
Heng Zhao ◽  
Jae Hoon Sung ◽  
Guohua Sun ◽  
Daria Mochly-Rosen ◽  
...  

Mild hypothermia is a robust neuroprotective treatment for stroke. Understanding the mechanisms underlying hypothermia's benefits will lead to more effective treatments to prevent stroke damage. Delta protein kinase C ( δPKC) is a kinase that has been strongly implicated in executing ischemic damage. We investigated the effects of hypothermia on δPKC activation, as determined by its subcellular translocation, proteolytic cleavage, and phosphorylation in a focal cerebral ischemia model. The amount of constitutively activated C-terminal catalytic fragment of δPKC (CF- δPKC) increased after stroke. Both hypothermia (30 C) and the caspase-3-specific inhibitor, Z-DQMD-FMK, blocked the accumulation of activated δPKC in the penumbra. Other hallmarks of δPKC activation, its translocation to the mitochondria, and nucleus were observed in the penumbra as early as 10 mins after reperfusion. These events were blocked by hypothermia. Hypothermia also blocked CF- δPKC increases in the mitochondria and nuclei. Conversely, a specific δPKC activator, ψδRACK, decreased the neuroprotective effect of hypothermia. Finally, δPKC activity may lead to mitochondrial injury and cytochrome c release, as the timing of cytochrome c release corresponded to the time course of δPKC translocation. Both cytochrome c release and δPKC translocation were blocked by hypothermia. In conclusion, hypothermia protects against ischemic damage in part by suppressing δPKC activation after stroke.


2016 ◽  
Vol 39 (2) ◽  
pp. 511-520 ◽  
Author(s):  
Jihong Xing ◽  
Jian Lu

Background/Aims: This study was to examine the role played by hypoxia inducible factor-1 (HIF-1α) in regulating pro-inflammatory cytokines (PICs) pathway in the rat hippocampus after cardiac arrest (CA) induced-transient global ischemia followed by cardiopulmonary resuscitation (CPR). Those PICs include interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Methods: A rat model of CA induced by asphyxia was used in the current study. Following CPR, the hippocampus CA1 region was obtained for ELISA to determine the levels of HIF-1α and PICs; and Western Blot analysis to determine the protein levels of PIC receptors. Results: Our data show that IL-1β, IL-6 and TNF-α were significant elevated in the hippocampus after CPR as compared with control group. This was companied with increasing of HIF-1α and the time courses for HIF-1α and PICs were similar. In addition, PIC receptors, namely IL-1R, IL-6R and TNFR1 were upregulated in CA rats. Also, stimulation of HIF-1α by systemic administration of ML228, HIF-1α activator, significantly attenuated the amplified IL-6/IL-6R and TNF-α /TNFR1 pathway in the hippocampus of CA rats, but did not modify IL-1β and its receptor. Moreover, ML228 attenuated upregulated expression of Caspase-3 indicating cell apoptosis evoked by CA. Conclusion: Transient global ischemia induced by CA increases the levels of IL-1β, IL-6 and TNF-α and thereby leads to enhancement in their respective receptor in the rat hippocampus. Stabilization of HIF-1α plays a role in attenuating amplified expression IL-6R, TNFR1 and Caspase-3 in the processing of transient global ischemia. Results of our study suggest that PICs contribute to cerebral injuries evoked by transient global ischemia and in this pathophysiological process activation of HIF-1α improves tissues against ischemic injuries. Our data revealed specific signaling pathways in alleviating CA-evoked global cerebral ischemia by elucidating that HIF-1α plays an important role in regulating PIC signal pathways and Caspase-3. The subsequent induction of HIF-1α and its target signals is likely a part of the intrinsic neuroprotective effects aimed at attenuating damage as a result of global cerebral ischemia. Thus, targeting one or more of these signaling molecules has clinical implications for treatment and improvement of CA-evoked global cerebral ischemia often observed in clinics.


2002 ◽  
Vol 22 (4) ◽  
pp. 420-430 ◽  
Author(s):  
Ramanjit Gill ◽  
Marc Soriano ◽  
Klas Blomgren ◽  
Henrik Hagberg ◽  
Remy Wybrecht ◽  
...  

These studies have addressed the role of caspase-3 activation in neuronal death after cerebral ischemia in different animal models. The authors were unable to show activation of procaspase-3 measured as an induction of DEVDase (Asp-Glu-Val-Asp) activity after focal or transient forebrain ischemia in rats. DEVDase activity could not be induced in the cytosolic fraction of the brain tissue obtained from these animals by exogenous cytochrome c/dATP and Ca2+. However, the addition of granzyme B to these cytosolic fractions resulted in a significant activation of DEVDase, confirming that the conditions were permissive to analyze proteolytic cleavage of the DEVD-AMC (7-amino-4-methyl-coumarin) substrate. Consistent with these findings, zVal-Ala-Asp-fluoromethylketone administered after focal ischemia did not have a neuroprotective effect. In contrast to these findings, a large increase in DEVDase activity was detected in a model of hypoxic-ischemia in postnatal-day-7 rats. Furthermore, in postnatal-day-7 animals treated with MK-801, in which it has been suggested that excessive apoptosis is induced, the authors were unable to detect activation of DEVDase activity but were able to induce it in vitro by the addition of cytochrome c/dATP and Ca2+ to the cytosolic fraction. Analysis of cytochrome c distribution did not provide definitive evidence for selective cytochrome c release in the permanent focal ischemia model, whereas in the transient model a small but consistent amount of cytochrome c was found in the cytosolic fraction. However, in both models the majority of cytochrome c remained associated with the mitochondrial fraction. In conclusion, the authors were unable to substantiate a role of mitochondrially derived cytochrome c and procaspase-3 activation in ischemia-induced cell death in adult brain, but did see a clear induction of caspase-3 in neonatal hypoxia.


2019 ◽  
Vol 19 (8) ◽  
pp. 597-604
Author(s):  
Li Pang ◽  
Shouqin Ji ◽  
Jihong Xing

Background: Central pro-inflammatory cytokine (PIC) signal is involved in neurological deficits after transient global ischemia induced by cardiac arrest (CA). The present study was to examine if blocking acid sensing ion channels (ASICs) using amiloride in the Central Nervous System can alleviate neurological deficits after the induction of CA and further examine the participation of PIC signal in the hippocampus for the effects of amiloride. Methods: CA was induced by asphyxia and then cardiopulmonary resuscitation was performed in rats. Western blot analysis and ELISA were used to determine the protein expression of ASIC subunit ASIC1 in the hippocampus, and the levels of PICs. As noted, it is unlikely that this procedure is clinically used although amiloride and other pharmacological agents were given into the brain in this study. Results: CA increased ASIC1 in the hippocampus of rats in comparison with control animals. This was associated with the increase in IL-1β, IL-6 and TNF-α together with Caspase-3 and Caspase-9. The administration of amiloride into the lateral ventricle attenuated the upregulation of Caspase-3/Caspase-9 and this further alleviated neurological severity score and brain edema. Inhibition of central IL-6 and TNF-α also decreased ASIC1 in the hippocampus of CA rats. Conclusion: Transient global ischemia induced by CA amplifies ASIC1a in the hippocampus likely via PIC signal. Amiloride administered into the Central Nervous System plays a neuroprotective role in the process of global ischemia. Thus, targeting ASICs (i.e., ASIC1a) is suggested for the treatment and improvement of CA-evoked global cerebral ischemia.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 182 ◽  
Author(s):  
Massimo Malerba ◽  
Raffaella Cerana

Fusicoccin (FC) is a well-known phytotoxin able to induce in Acer pseudoplatanus L. (sycamore) cultured cells, a set of responses similar to those induced by stress conditions. In this work, the possible involvement of peroxynitrite (ONOO−) in FC-induced stress responses was studied measuring both in the presence and in the absence of 2,6,8-trihydroxypurine (urate), a specific ONOO− scavenger: (1) cell death; (2) specific DNA fragmentation; (3) lipid peroxidation; (4) production of RNS and ROS; (5) activity of caspase-3-like proteases; and (6) release of cytochrome c from mitochondria, variations in the levels of molecular chaperones Hsp90 in the mitochondria and Hsp70 BiP in the endoplasmic reticulum (ER), and of regulatory 14-3-3 proteins in the cytosol. The obtained results indicate a role for ONOO− in the FC-induced responses. In particular, ONOO− seems involved in a PCD form showing apoptotic features such as specific DNA fragmentation, caspase-3-like protease activity, and cytochrome c release from mitochondria.


2005 ◽  
Vol 289 (6) ◽  
pp. H2310-H2318 ◽  
Author(s):  
Takayuki Okada ◽  
Hajime Otani ◽  
Yue Wu ◽  
Shiori Kyoi ◽  
Chiharu Enoki ◽  
...  

Activation of p38 mitogen-activated protein (MAP) kinase (MAPK) has been implicated in the mechanism of cardiomyocyte (CMC) protection and injury. The p38 MAPK controversy may be related to differential effects of this kinase on apoptosis and necrosis. We have hypothesized that p38 MAPK-mediated F-actin reorganization promotes apoptotic cell death, whereas it protects from osmotic stress-induced necrotic cell death. Cultured neonatal rat CMCs were subjected to 2 h of simulated ischemia followed by reoxygenation. p38 MAPK activity measured by phosphorylation of MAP kinase-activated protein (MAPKAP) kinase 2 was increased during simulated ischemia and reoxygenation. This was associated with translocation of heat shock protein 27 (HSP27) from the cytosolic to the cytoskeletal fraction and F-actin reorganization. Cytochrome c release from mitochondria, caspase-3 activation, and DNA fragmentation were increased during reoxygenation. Robust lactate dehydrogenase (LDH) release was observed under hyposmotic (140 mosM) reoxygenation. The p38 MAPK inhibitor SB-203580 abrogated activation of p38 MAPK, translocation of HSP27, and F-actin reorganization and prevented cytochrome c release, caspase-3 activation, and DNA fragmentation. Conversely, SB-203580 enhanced LDH release during hyposmotic reoxygenation. The F-actin disrupting agent cytochalasin D inhibited F-actin reorganization and prevented cytochrome c release, caspase-3 activation, and DNA fragmentation, whereas it enhanced LDH release during hyposmotic reoxygenation. When CMCs were incubated under the isosmotic condition for the first 15 min of reoxygenation, SB-203580 and cytochalasin D increased ATP content of CMCs and prevented LDH release after the conversion to the hyposmotic condition. These results suggest that F-actin reorganization mediated by activation of p38 MAPK plays a differential role in apoptosis and protection against osmotic stress-induced necrosis during reoxygenation in neonatal rat CMCs; however, the sarcolemmal fragility caused by p38 MAPK inhibition can be reversed during temporary blockade of physical stress during reoxygenation.


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.


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.


2003 ◽  
Vol 284 (5) ◽  
pp. G821-G829 ◽  
Author(s):  
Wenlin Deng ◽  
De-An Wang ◽  
Elvira Gosmanova ◽  
Leonard R. Johnson ◽  
Gabor Tigyi

We previously showed ( Gastroenterology 123: 206–216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through Gi-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.


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