scholarly journals Subfield-Specific Neurovascular Remodeling in the Entorhino-Hippocampal-Organotypic Slice Culture as a Response to Oxygen–Glucose Deprivation and Excitotoxic Cell Death

2012 ◽  
Vol 33 (4) ◽  
pp. 508-518 ◽  
Author(s):  
Sophorn Chip ◽  
Cordula Nitsch ◽  
Sven Wellmann ◽  
Josef P Kapfhammer

Transient ischemia causes delayed neurodegeneration in selective brain areas, particularly in the CA1 field of the hippocampus. This is accompanied by neurovascular impairment. It is unknown whether neurodegeneration is the cause or consequence of vascular changes. In an entorhino-hippocampal-organotypic slice culture system with well-preserved blood vessels, we studied the interplay between neurodegeneration and neurovasculature. Short-term oxygen and glucose deprivation (OGD) resulted in upregulation of hypoxic markers and with a delay of 24 to 48 hours in selective nerve cell death in CA1. In parallel, local vessel density decreased as detected by markers of endothelial cells and of the extracellular matrix. Claudin-5, a tight junction protein and marker of the blood–brain barrier was reduced. Preventing neuronal death with tetrodotoxin or 6-cyano-7-nitroquinoxaline-2,3-dione rescued blood vessels, suggesting that vessel loss is not due to OGD per se but a consequence of neuronal death. Induction of excitotoxic neuronal death with AMPA caused widespread neurodegeneration, but vessel reduction was confined to CA1. In dentate gyrus without neuronal loss, vessel density increased. We propose that neuronal stress and death influence maintenance, loss and remodeling of the neurovasculature and that the type of vascular response is in addition determined by local factors within the hippocampus.

2002 ◽  
Vol 96 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Breandan L. Sullivan ◽  
David Leu ◽  
Donald M. Taylor ◽  
Christian S. Fahlman ◽  
Philip E. Bickler

Background General anesthetics reduce neuronal death caused by focal cerebral ischemia in rodents and by in vitro ischemia in cultured neurons and brain slices. However, in intact animals, the protective effect may enhance neuronal survival for only several days after an ischemic injury, possibly because anesthetics prevent acute but not delayed cell death. To further understand the mechanisms and limitations of volatile anesthetic neuroprotection, the authors developed a rat hippocampal slice culture model of cerebral ischemia that permits assessment of death and survival of neurons for at least 2 weeks after simulated ischemia. Methods Survival of CA1, CA3, and dentate gyrus neurons in cultured hippocampal slices (organotypic slice culture) was examined 2-14 days after 45 min of combined oxygen-glucose deprivation at 37 degrees C (OGD). Delayed cell death was serially measured in each slice by quantifying the binding of propidium iodide to DNA with fluorescence microscopy. Results Neuronal death was greatest in the CA1 region, with maximal death occurring 3-5 days after OGD. In CA1, cell death was 80 +/- 18% (mean +/- SD) 3 days after OGD and was 80-100% after 1 week. Death of 70 +/- 16% of CA3 neurons and 48 +/- 28% of dentate gyrus neurons occurred by the third day after OGD. Both isoflurane (1%) and the N-methyl-D-aspartate antagonist MK-801 (10 microm) reduced cell death to levels similar to controls (no OGD) for 14 days after the injury. Isoflurane also reduced cell death in CA1 and CA3 caused by application of 100 but not 500 microm glutamate. Cellular viability (calcein fluorescence) and morphology were preserved in isoflurane-protected neurons. Conclusions In an in vitro model of simulated ischemia, 1% isoflurane is of similar potency to 10 microm MK-801 in preventing delayed cell death. Modulation of glutamate excitotoxicity may contribute to the protective mechanism.


2007 ◽  
Vol 28 (4) ◽  
pp. 737-746 ◽  
Author(s):  
Jing Luo ◽  
Yanping Wang ◽  
Hai Chen ◽  
Douglas B Kintner ◽  
Sam W Cramer ◽  
...  

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.


2003 ◽  
Vol 23 (3) ◽  
pp. 381-384 ◽  
Author(s):  
Rosalind A. Le Feuvre ◽  
David Brough ◽  
Omar Touzani ◽  
Nancy J. Rothwell

Purinergic P2X7 receptors may affect neuronal cell death through their ability to regulate the processing and release of interleukin-1β (IL-1β), a key mediator in neurodegeneration. The authors tested the hypothesis that ATP, acting at P2X7 receptors, contributes to experimentally induced neuronal death in rodents in vivo. Deletion of P2X7 receptors (P2X7 knockout mice) did not affect cell death induced by temporary cerebral ischemia, which was reduced by treatment with IL-1 receptor antagonist (IL-1RA). Treatment of mice with P2X antagonists did not affect ischemic or excitotoxic cell death, suggesting that P2X7 receptors are not primary mediators of experimentally induced neuronal death.


2020 ◽  
Author(s):  
S. Sadia Ameen ◽  
Antoine Dufour ◽  
M. Iqbal Hossain ◽  
Ashfaqul Hoque ◽  
Sharelle Sturgeon ◽  
...  

SummaryExcitotoxicity, a neuronal death process in neurological disorders, is initiated by over-stimulation of neuronal ionotropic glutamate receptors. The over-stimulated receptors dysregulate proteases, protein kinases and phosphatases, which in turn modify target neuronal proteins to induce cell death. To decipher this cell death mechanism, we used quantitative proteomics, phosphoproteomics and N-terminomics to identify modified proteins in excitotoxic neurons. Data, available in ProteomeXchange (identifiers: PXD019527 and PXD019211), enabled us to identify over one thousand such proteins with calpains, cathepsins and over twenty protein kinases as their major modifiers. These protein modification events can potentially perturb signalling pathways governing cell survival, synaptogenesis, axonal guidance and mRNA processing. Importantly, blocking the modification of Src protein kinase, a signalling hub in excitotoxic neurons, protected against neuronal loss in vivo in a rat model of neurotoxicity. Besides offering new insights into excitotoxic neuronal death mechanism, our findings suggest potential neuroprotective therapeutic targets for treating neurological disorders.Graphical abstractHighlightsMulti-dimensional proteomic analysis identified proteins modified by proteolysis and altered phosphorylation in neurons undergoing excitotoxic cell death.Calpains, cathepsins and over twenty protein kinases are major modifiers of these proteins.These protein modification events are predicted to impact cell survival, axonal guidance, synaptogenesis and mRNA processing.Blocking modification of an identified protein Src, which acts as a major signalling hub in neurons, was protective against excitotoxic injury in vivo.In BriefUsing multidimensional proteomic approaches, Ameen, et al. mapped the changes of proteome, phosphoproteome and N-terminome of cultured primary neurons during excitotoxicity, a crucial neuronal death process in neurological disorders. These proteomic changes document new excitotoxicity-associated molecular events, and offer insights into how these events are organized to induce neuronal death. Potential therapeutic relevance of these molecular events is illustrated by the demonstration that in vivo blockade of one of these events could protect against excitotoxic neuronal loss.


2019 ◽  
Vol 20 (22) ◽  
pp. 5632 ◽  
Author(s):  
Darya V. Telegina ◽  
Gleb K. Suvorov ◽  
Oyuna S. Kozhevnikova ◽  
Nataliya G. Kolosova

Alzheimer’s disease (AD) is the commonest type of late-life dementia and damages the cerebral cortex, a vulnerable brain region implicated in memory, emotion, cognition, and decision-making behavior. AD is characterized by progressive neuronal loss, but the mechanisms of cell death at different stages of the disease remain unknown. Here, by means of OXYS rats as an appropriate model of the most common (sporadic) AD form, we studied the main pathways of cell death during development of AD-like pathology, including the preclinical stage. We found that apoptosis is activated at the pre-symptomatic stage (age 20 days) correlating with the retardation of brain development in the OXYS strain early in life. Progression of the AD-like pathology was accompanied by activation of apoptosis and necroptosis resulting from a decline of autophagy-mediated proteostasis. Our results are consistent with the idea that the nature of changes in the pathways of apoptosis, autophagy, and necrosis depends on the stage of AD.


2010 ◽  
Vol 104 (6) ◽  
pp. 3551-3556 ◽  
Author(s):  
Yongfu Wang ◽  
Janna V. Denisova ◽  
Ki Sung Kang ◽  
Joseph D. Fontes ◽  
Bao Ting Zhu ◽  
...  

N-methyl-d-aspartate receptors (NMDARs) play an important role in cell survival versus cell death decisions during neuronal development, ischemia, trauma, and epilepsy. Coupling of neurons by electrical synapses (gap junctions) is high or increases in neuronal networks during all these conditions. In the developing CNS, neuronal gap junctions are critical for two different types of NMDAR-dependent cell death. However, whether neuronal gap junctions play a role in NMDAR-dependent neuronal death in the mature CNS was not known. Using Fluoro-Jade B staining, we show that a single intraperitoneal administration of NMDA (100 mg/kg) to adult wild-type mice induces neurodegeneration in three forebrain regions, including rostral dentate gyrus. However, the NMDAR-mediated neuronal death is prevented by pharmacological blockade of neuronal gap junctions (with mefloquine, 30 mg/kg) and does not occur in mice lacking neuronal gap junction protein, connexin 36. Using Western blots, electrophysiology, calcium imaging, and gas chromatography–mass spectrometry in wild-type and connexin 36 knockout mice, we show that the reduced level of neuronal death in knockout animals is not caused by the reduced expression of NMDARs, activity of NMDARs, or permeability of the blood–brain barrier to NMDA. In wild-type animals, this neuronal death is not caused by upregulation of connexin 36 by NMDA. Finally, pharmacological and genetic inactivation of neuronal gap junctions in mice also dramatically reduces neuronal death caused by photothrombotic focal cerebral ischemia. The results indicate that neuronal gap junctions are required for NMDAR-dependent excitotoxicity and play a critical role in ischemic neuronal death.


2010 ◽  
Vol 112 (2) ◽  
pp. 373-383 ◽  
Author(s):  
Souhayl Dahmani ◽  
Danielle Rouelle ◽  
Pierre Gressens ◽  
Jean Mantz

Background There is an increasing interest in the use of dexmedetomidine for anesthesia and sedation. Here, we used the mouse organotypic hippocampal slice culture to investigate whether dexmedetomidine exhibits postconditioning properties against oxygen and glucose deprivation (OGD). The role of the focal adhesion and extracellular-regulated kinases pathways in these effects were examined in both postconditioning and preconditioning. Materials and Methods Slices were obtained from P5 mouse. In postconditioning experiments, Dexmedetomidine (1 microm) was incubated 60 min after the end of OGD. In preconditioning experiments, dexmedetomidine was applied 3 h before OGD. Pharmacologic modulation of the studied pathways was achieved by using selective inhibitors of these cascades. Cell death was assessed 72 h after OGD using propidium iodide labeling and protein expression of activated caspase 3. Results Maximum cell death increased with the duration of OGD. Dexmedetomidine induced a postconditioning effect in the CA1 (but not dentate gyrus) subfield area, which was significantly reduced by modulators of the focal adhesion and the extracellular-regulated kinases pathways. The combination of the inhibitors of the two pathways completely abolished the postconditioning effect of dexmedetomidine. The preconditioning effect of dexmedetomidine against ischemia-induced injury was observed in all hippocampal subfield areas. Results obtained with the pharmacologic modulation used for postconditioning also applied to dexmedetomidine-induced preconditioning. Discussion Dexmedetomidine exhibits significant, but moderate, postconditioning properties against oxygen and glucose deprivation-induced injury. Activation of focal adhesion and the imidazoline 1 receptors-extracellular-regulated kinases pathways is involved in dexmedetomidine-induced postconditioning and preconditioning as well.


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