scholarly journals Evidence for the Involvement of Par-4 in Ischemic Neuron Cell Death

2001 ◽  
Vol 21 (4) ◽  
pp. 334-343 ◽  
Author(s):  
Carsten Culmsee ◽  
Yuan Zhu ◽  
Josef Krieglstein ◽  
Mark P. Mattson
Keyword(s):  
Cell Death ◽  
Neuronal Death ◽  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Time Course ◽  
Current Data ◽  
Striatal Neurons ◽  
Similar Time ◽  
Chemical Hypoxia ◽  
Cultured Hippocampal Neurons

After a stroke many neurons in the ischemic brain tissue die by a process called apoptosis, a form of cell death that may be preventable. The specific molecular cascades that mediate ischemic neuronal death are not well understood. The authors recently identified prostate apoptosis response-4 (Par-4) as a protein that participates in the death of cultured hippocampal neurons induced by trophic factor withdrawal and exposure to glutamate. Here, the authors show that Par-4 levels increase in vulnerable populations of hippocampal and striatal neurons in rats after transient forebrain ischemia; Par-4 levels increased within 6 hours of reperfusion and remained elevated in neurons undergoing apoptosis 3 days later. After transient focal ischemia in mice, Par-4 levels were increased 6 to12 hours after reperfusion in the infarcted cortex and the striatum, and activation of caspase-8 occurred with a similar time course. Par-4 immunoreactivity was localized predominantly in cortical neurons at the border of the infarct area. A Par-4 antisense oligonucleotide protected cultured hippocampal neurons against apoptosis induced by chemical hypoxia and significantly reduced focal ischemic damage in mice. The current data suggest that early up-regulation of Par-4 plays a pivotal role in ischemic neuronal death in animal models of stroke and cardiac arrest.

Glycine regulation of synaptic NMDA receptors in hippocampal neurons

1996 ◽  
Vol 76 (5) ◽  
pp. 3415-3424 ◽  
Author(s):  
K. S. Wilcox ◽  
R. M. Fitzsimonds ◽  
B. Johnson ◽  
M. A. Dichter
Keyword(s):  
Nmda Receptor ◽  
Nmda Receptors ◽  
Hippocampal Neurons ◽  
Time Course ◽  
Hippocampal Slices ◽  
Maximal Effect ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Dissociated Cell Culture ◽  
Cultured Hippocampal Neurons

1. Although glycine has been identified as a required coagonist with glutamate at N-methyl-D-aspartate (NMDA) receptors, the understanding of glycine's role in excitatory synaptic neurotransmission is quite limited. In the present study, we used the whole cell patch-clamp technique to examine the ability of glycine to regulate current flow through synaptic NMDA receptors at excitatory synapses between cultured hippocampal neurons and in acutely isolated hippocampal slices. 2. These studies demonstrate that the glycine modulatory site on the synaptic NMDA receptor is not saturated under baseline conditions and that increased glycine concentrations can markedly increased NMDA-receptor-mediated excitatory postsynaptic currents (EPSCs) in hippocampal neurons in both dissociated cell culture and in slice. Saturation of the maximal effect of glycine takes place at different concentrations for different cells in culture, suggesting the presence of heterogenous NMDA receptor subunit compositions. 3. Bath-applied glycine had no effect on the time course of EPSCs in either brain slice or culture, indicating that desensitization of the NMDA receptor is not prevented by glycine over the time course of an EPSC. 4. When extracellular glycine concentration is high, all miniature EPSCs recorded in the cultured hippocampal neurons contained NMDA components, indicating that segregation of non-NMDA receptors at individual synaptic boutons does not occur.

Gadolinium Reduces AMPA Receptor Desensitization and Deactivation in Hippocampal Neurons

2001 ◽  
Vol 86 (1) ◽  
pp. 173-182 ◽  
Author(s):  
Saobo Lei ◽  
John F. MacDonald
Keyword(s):  
Steady State ◽  
Ampa Receptor ◽  
Hippocampal Neurons ◽  
Time Course ◽  
Single Channel ◽  
Trivalent Cation ◽  
Receptor Desensitization ◽  
Whole Cell ◽  
Low Concentrations ◽  
Cultured Hippocampal Neurons

The actions of the trivalent cation Gd3+ on whole cell AMPA receptor-mediated currents were studied in isolated hippocampal neurons, in nucleated or outside-out patches taken from cultured hippocampal neurons, and on miniature excitatory postsynaptic currents (mEPSCs) recorded in cultured hippocampal neurons. Glutamate, AMPA, or kainate was employed to activate AMPA receptors. Applications of relatively low concentrations of Gd3+ (0.1–10 μM) substantially enhanced steady-state whole cell glutamate and kainate-evoked currents without altering peak currents, suggesting that desensitization was reduced. However, higher concentrations (>30 μM) depressed steady-state currents, indicating an underlying inhibition of channel activity. Lower concentrations of Gd3+also increased the potency of peak glutamate-evoked currents without altering that of steady-state currents. An ultrafast perfusion system and nucleated patches were then used to better resolve peak glutamate-evoked currents. Low concentrations of Gd3+ reduced peak currents, enhanced steady-state currents, and slowed the onset of desensitization, providing further evidence that this cation reduces desensitization. In the presence of cyclothiazide, a compound that blocks desensitization, a low concentration Gd3+ inhibited both peak and steady-state currents, indicating that Gd3+ both reduces desensitization and inhibits these currents. Gd3+ reduced the probability of channel opening at the peak of the currents but did not alter the single channel conductance calculated using nonstationary variance analysis. Recovery from desensitization was enhanced, and glutamate-evoked current activation and deactivation were slowed by Gd3+. The Gd3+-induced reduction in desensitization did not require the presence of the GluR2 subunit as this effect was seen in hippocampal neurons from GluR2 null-mutant mice. Gd3+ reduced the time course of decay of mEPSCs perhaps as a consequence of its slowing of AMPA receptor deactivation although an increase in the frequency of mEPSCs also suggested enhanced presynaptic release of transmitter. These results demonstrate that Gd3+ potently reduces AMPA receptor desensitization and mimics a number of the properties of the positive modulators of AMPA receptor desensitization such as cyclothiazide.

Dynamic Recording of Cell Death in the In Vitro Dorsal Vagal Nucleus of Rats in Response to Metabolic Arrest

2003 ◽  
Vol 89 (1) ◽  
pp. 551-561 ◽  
Author(s):  
Michael Müller ◽  
Klaus Ballanyi
Keyword(s):  
Cell Death ◽  
Propidium Iodide ◽  
Neuronal Death ◽  
Time Course ◽  
Time Window ◽  
Membrane Integrity ◽  
Brain Slices ◽  
Limited Information ◽  
Histological Techniques ◽  
Metabolic Arrest

Anoxic/ischemic neuronal death is usually assessed in cell cultures or in vivo within a time window of 24 h to several days using the nucleic acid stain propidium iodide or histological techniques. Accordingly, there is limited information on the time course of such neuronal death. We loaded acute rat brain stem slices with propidium iodide for dynamic fluorometric recording of metabolic arrest-related cell death in the dorsal vagal nucleus. This model was chosen because dorsal vagal neurons show a graded response to metabolic inhibition: anoxia and aglycemia cause a sustained hyperpolarization, whereas ischemia induces a glutamate-mediated, irreversible depolarization. We found that the number of propidium iodide–labeled cells increased from 27% to 43% of total cell count within 1–7 h after preparation of slices. Compared with these untreated control slices, cyanide-induced anoxia (30 min) or aglycemia (1 h) did not cause further cell death, whereas 3-h aglycemia destroyed an additional 13% of cells. Ischemia (1 h) due to cyanide plus iodoacetate immediately labeled an additional 20% of cells, and an additional 48% of cells were destroyed within the following 3 h of postischemia. Continuous recording of propidium iodide fluorescence showed that loss of membrane integrity started within 25 min after onset of the ischemic depolarization and the concomitant intracellular Ca2+ rise. The results show that propidium iodide can be used to monitor cell death in acute brain slices. Our findings suggest that pronounced cell death occurs within a period of 1–4 h after onset of metabolic arrest and is apparently due to necrotic/oncotic mechanisms.

Evidence for Involvement of p53 and Bax (but Not ICE-Related Proteases) in Radiation-Induced Cell Death of Primary Cultured Hippocampal Neurons

Neurosurgery ◽  
1997 ◽  
Vol 41 (3) ◽  
pp. 733-734
Author(s):  
Mark Johnson ◽  
Susan London ◽  
Hong Xiang ◽  
Yoshito Kinoshita ◽  
Marc Mayberg ◽  
...  
Keyword(s):  
Cell Death ◽  
Hippocampal Neurons ◽  
Radiation Induced ◽  
Cultured Hippocampal Neurons

Mechanism of glucocorticoid-induced oxidative stress in rat hippocampal slice cultures

2009 ◽  
Vol 87 (6) ◽  
pp. 440-447 ◽  
Author(s):  
Jung-Man You ◽  
Su-Jin Yun ◽  
Kyong Nyon Nam ◽  
Chulhun Kang ◽  
Ran Won ◽  
...  
Keyword(s):  
Cell Death ◽  
Hippocampal Neurons ◽  
Time Course ◽  
Glucocorticoid Receptors ◽  
Hippocampal Slice ◽  
Pcr Analysis ◽  
Ros Generation ◽  
Hippocampal Damage ◽  
Ros Production ◽  
Hippocampal Slice Cultures

Prolonged stress results in elevation of glucocorticoid (GC) hormones, which can have deleterious effects in the brain. The hippocampus, which has a high concentration of glucocorticoid receptors, is especially vulnerable to increasing levels of GCs. GCs have been suggested to endanger hippocampal neurons by exacerbating the excitotoxic glutamate–calcium–reactive oxygen species (ROS) cascade. In an effort to reveal the mechanisms underlying GC-mediated hippocampal neurotoxicity, we aimed to clarify the molecular pathway of GC-induced ROS increase by using organotypic hippocampal slice cultures. Assays for ROS, using 2′,7′-dichlorodihydrofluorescein diacetate fluorescence, showed that treatment of synthetic GC, dexamethasone (DEX) significantly enhanced ROS levels. Time course and dose response analyses indicated that peak amount of ROS was generated at 4 h after treatment with 50 µmol/L DEX. By contrast, other steroid hormones, progesterone and estradiol did not influence ROS production. N-acetyl-l-cysteine completely suppressed ROS produced by DEX. Propidium iodide staining exhibited prominent cell death in the hippocampal layer after 96 h of DEX treatment. RU486, a GC receptor antagonist, almost completely blocked the effect of DEX on ROS production and cell death, indicating that DEX-induced ROS overproduction and hippocampal death are mediated via GC receptors. Real-time reverse transcriptase PCR analysis demonstrated that after DEX treatment the level of glutathione peroxidase mRNA was decreased whereas that of NADPH oxidase mRNA was significantly enhanced. These findings suggest that excess GCs cause hippocampal damage by regulating genes involved in ROS generation.

scholarly journals A Concerted Role of Na+—K+—Cl− Cotransporter and Na+/Ca2+ Exchanger in Ischemic Damage

2007 ◽  
Vol 28 (4) ◽  
pp. 737-746 ◽  
Author(s):  
Jing Luo ◽  
Yanping Wang ◽  
Hai Chen ◽  
Douglas B Kintner ◽  
Sam W Cramer ◽  
...  
Keyword(s):  
Cell Death ◽  
Cerebral Ischemia ◽  
Mortality Rate ◽  
Neuronal Death ◽  
Cortical Neurons ◽  
Infarct Volume ◽  
Glucose Deprivation ◽  
Ischemic Damage ◽  
Oxygen And Glucose Deprivation

Na+–K+–Cl− cotransporter isoform 1 (NKCC1) and Na+/Ca2+ exchanger isoform 1 (NCX1) were expressed in cortical neurons. Three hours of oxygen and glucose deprivation (OGD) significantly increased expression of full-length NCX1 protein (∼116 kDa), which remained elevated during 1 to 21 h reoxygenation (REOX) and was accompanied with concurrent cleavage of NCX1. Na+/Ca2+ exchanger isoform 1 heterozygous (NCX1+/−) neurons with ∼50% less of NCX1 protein exhibited ∼64% reduction in NCX-mediated Ca2+ influx. Expression of NCX1 and NKCC1 proteins was reduced in double heterozygous (NCX1+/−/NKCC1+/−) neurons. NCX-mediated Ca2+ influx was nearly abolished in these neurons. Three-hour OGD and 21-h REOX caused ∼80% mortality rate in NCX1+/+ neurons and in NCX1+/− neurons. In contrast, NKCC1+/− neurons exhibited ∼45% less cell death. The lowest mortality rate was found in NCX1+/−/NKCC1+/− neurons (∼65% less neuronal death). The increased tolerance to ischemic damage was also observed in NCX1+/−/NKCC1+/− brains after transient cerebral ischemia. NCX1+/−/NKCC1+/− mice had a significantly reduced infarct volume at 24 and 72 h reperfusion. In conclusion, these data suggest that NKCC1 in conjunction with NCX1 plays a role in reperfusion-induced brain injury after ischemia.

scholarly journals HIV and FIV glycoproteins increase cellular tau pathology via cGMP-dependent kinase II activation

2022 ◽  
Author(s):  
Matheus F Sathler ◽  
Michael J Doolittle ◽  
James A Cockrell ◽  
India R Nadalin ◽  
Franz Hofmann ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Tau Pathology ◽  
Viral Glycoprotein ◽  
Viral Glycoproteins ◽  
Immunodeficiency Virus ◽  
Hiv Gp120 ◽  
The Brain ◽  
Cultured Hippocampal Neurons

As the development of combination antiretroviral therapy (cART) against human immunodeficiency virus (HIV) drastically improves the lifespan of individuals with HIV, many are now entering the prime age when Alzheimer's disease (AD)-like symptoms begin to manifest. Hyperphosphorylated tau, a known AD pathological characteristic, has been prematurely increased in the brains of HIV-infected patients as early as in their 30s and is increased with age. This thus suggests that HIV infection may lead to accelerated AD phenotypes. However, whether HIV infection causes AD to develop more quickly in the brain is not yet fully determined. Interestingly, we have previously revealed that viral glycoproteins, HIV gp120 and feline immunodeficiency virus (FIV) gp95, induce neuronal hyperexcitation via cGMP-dependent kinase II (cGKII) activation in cultured hippocampal neurons. Here, we use cultured mouse cortical neurons to demonstrate that HIV gp120 and FIV gp95 are sufficient to increase cellular tau pathology, including intracellular tau hyperphosphorylation and tau release to the extracellular space. We further reveal that viral glycoprotein-induced cellular tau pathology requires cGKII activation. Together, HIV infection likely accelerates AD-related tau pathology via cGKII activation.

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