scholarly journals Increased BDNF Protein Expression after Ischemic Or PKC Epsilon Preconditioning Promotes Electrophysiologic Changes That Lead to Neuroprotection

2014 ◽  
Vol 35 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Jake T Neumann ◽  
John W Thompson ◽  
Ami P Raval ◽  
Charles H Cohan ◽  
Kevin B Koronowski ◽  
...  
Keyword(s):  
Protein Expression ◽  
Cortical Neurons ◽  
Neuronal Excitability ◽  
Hippocampal Slices ◽  
Glucose Deprivation ◽  
Neuronal Firing ◽  
Trk Receptors ◽  
Bdnf Mrna

Ischemic preconditioning (IPC) via protein kinase C epsilon (PKCε) activation induces neuroprotection against lethal ischemia. Brain-derived neurotrophic factor (BDNF) is a pro-survival signaling molecule that modulates synaptic plasticity and neurogenesis. Interestingly, BDNF mRNA expression increases after IPC. In this study, we investigated whether IPC or pharmacological preconditioning (PKCε activation) promoted BDNF-induced neuroprotection, if neuroprotection by IPC or PKCε activation altered neuronal excitability, and whether these changes were BDNF-mediated. We used both in vitro (hippocampal organotypic cultures and cortical neuronal-glial cocultures) and in vivo (acute hippocampal slices 48 hours after preconditioning) models of IPC or PKCε activation. BDNF protein expression increased 24 to 48 hours after preconditioning, where inhibition of the BDNF Trk receptors abolished neuroprotection against oxygen and glucose deprivation (OGD) in vitro. In addition, there was a significant decrease in neuronal firing frequency and increase in threshold potential 48 hours after preconditioning in vivo, where this threshold modulation was dependent on BDNF activation of Trk receptors in excitatory cortical neurons. In addition, 48 hours after PKCε activation in vivo, the onset of anoxic depolarization during OGD was significantly delayed in hippocampal slices. Overall, these results suggest that after IPC or PKCε activation, there are BDNF-dependent electrophysiologic modifications that lead to neuroprotection.

scholarly journals Modulator of apoptosis-1 is a potential therapeutic target in acute ischemic injury

2018 ◽  
Vol 39 (12) ◽  
pp. 2406-2418 ◽  
Author(s):  
Su Jing Chan ◽  
Hui Zhao ◽  
Kazuhide Hayakawa ◽  
Chou Chai ◽  
Chong Teik Tan ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Infarct Volume ◽  
Neuronal Loss ◽  
Ischemic Injury ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
In Vivo Models ◽  
The Brain

Modulator of apoptosis 1 (MOAP-1) is a Bax-associating protein highly enriched in the brain. In this study, we examined the role of MOAP-1 in promoting ischemic injuries following a stroke by investigating the consequences of MOAP-1 overexpression or deficiency in in vitro and in vivo models of ischemic stroke. MOAP-1 overexpressing SH-SY5Y cells showed significantly lower cell viability following oxygen and glucose deprivation (OGD) treatment when compared to control cells. Consistently, MOAP-1−/− primary cortical neurons were observed to be more resistant against OGD treatment than the MOAP-1+/+ primary neurons. In the mouse transient middle cerebral artery occlusion (tMCAO) model, ischemia triggered MOAP-1/Bax association, suggested activation of the MOAP-1-dependent apoptotic cascade. MOAP-1−/− mice were found to exhibit reduced neuronal loss and smaller infarct volume 24 h after tMCAO when compared to MOAP-1+/+ mice. Correspondingly, MOAP-1−/− mice also showed better integrity of neurological functions as demonstrated by their performance in the rotarod test. Therefore, both in vitro and in vivo data presented strongly support the conclusion that MOAP-1 is an important apoptotic modulator in ischemic injury. These results may suggest that a reduction of MOAP-1 function in the brain could be a potential therapeutic approach in the treatment of acute stroke.

scholarly journals Ras-like Gem GTPase induced by Npas4 promotes activity-dependent neuronal tolerance for ischemic stroke

2021 ◽  
Vol 118 (32) ◽  
pp. e2018850118
Author(s):  
Hiroo Takahashi ◽  
Ryo Asahina ◽  
Masayuki Fujioka ◽  
Takeshi K. Matsui ◽  
Shigeki Kato ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cortical Neurons ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Small Gtpase ◽  
Neuroprotective Effects ◽  
Necessary And Sufficient ◽  
Activity Dependent

Ischemic stroke, which results in loss of neurological function, initiates a complex cascade of pathological events in the brain, largely driven by excitotoxic Ca2+ influx in neurons. This leads to cortical spreading depolarization, which induces expression of genes involved in both neuronal death and survival; yet, the functions of these genes remain poorly understood. Here, we profiled gene expression changes that are common to ischemia (modeled by middle cerebral artery occlusion [MCAO]) and to experience-dependent activation (modeled by exposure to an enriched environment [EE]), which also induces Ca2+ transients that trigger transcriptional programs. We found that the activity-dependent transcription factor Npas4 was up-regulated under MCAO and EE conditions and that transient activation of cortical neurons in the healthy brain by the EE decreased cell death after stroke. Furthermore, both MCAO in vivo and oxygen-glucose deprivation in vitro revealed that Npas4 is necessary and sufficient for neuroprotection. We also found that this protection involves the inhibition of L-type voltage-gated Ca2+ channels (VGCCs). Next, our systematic search for Npas4-downstream genes identified Gem, which encodes a Ras-related small GTPase that mediates neuroprotective effects of Npas4. Gem suppresses the membrane localization of L-type VGCCs to inhibit excess Ca2+ influx, thereby protecting neurons from excitotoxic death after in vitro and in vivo ischemia. Collectively, our findings indicate that Gem expression via Npas4 is necessary and sufficient to promote neuroprotection in the injured brain. Importantly, Gem is also induced in human cerebral organoids cultured under an ischemic condition, revealing Gem as a new target for drug discovery.

GATA3 (GATA-Binding Protein 3)/KMT2A (Lysine-Methyltransferase-2A) Complex by Increasing H3K4-3me (Trimethylated Lysine-4 of Histone-3) Upregulates NCX3 (Na + -Ca 2+ Exchanger 3) Transcription and Contributes to Ischemic Preconditioning Neuroprotection

Stroke ◽  
2021 ◽  
Vol 52 (11) ◽  
pp. 3680-3691
Author(s):  
Natascia Guida ◽  
Luigi Mascolo ◽  
Angelo Serani ◽  
Ornella Cuomo ◽  
Serenella Anzilotti ◽  
...  
Keyword(s):  
Ischemic Preconditioning ◽  
Cortical Neurons ◽  
Promoter Region ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Histone 3 ◽  
Lysine Methyltransferase ◽  
Cerebral Artery Occlusion

Background and Purpose: NCX3 (Na + -Ca 2+ exchanger 3) plays a relevant role in stroke; indeed its pharmacological blockade or its genetic ablation exacerbates brain ischemic damage, whereas its upregulation takes part in the neuroprotection elicited by ischemic preconditioning. To identify an effective strategy to induce an overexpression of NCX3, we examined transcription factors and epigenetic mechanisms potentially involved in NCX3 gene regulation. Methods: Brain ischemia and ischemic preconditioning were induced in vitro by exposure of cortical neurons to oxygen and glucose deprivation plus reoxygenation (OGD/Reoxy) and in vivo by transient middle cerebral artery occlusion. Western blot and quantitative real-time polymerase chain reaction were used to evaluate transcripts and proteins of GATA3 (GATA-binding protein 3), KMT2A (lysine-methyltransferase-2A), and NCX3. GATA3 and KMT2A binding on NCX3 gene was evaluated by chromatin immunoprecipitation and Rechromatin immunoprecipitation experiments. Results: Among the putative transcription factors sharing a consensus sequence on the ncx3 brain promoter region, GATA3 was the only able to up-regulate ncx3. Interestingly, GATA3 physically interacted with KMT2A, and their overexpression or knocking-down increased or downregulated NCX3 mRNA and protein, respectively. Notably, site-direct mutagenesis of GATA site on ncx3 brain promoter region counteracted GATA3 and KMT2A binding on NCX3 gene. More importantly, we found that in the perischemic cortical regions of preconditioned rats GATA3 recruited KMT2A and the complex H3K4-3me (trimethylated lysine-4 of histone-3) on ncx3 brain promoter region, thus reducing transient middle cerebral artery occlusion–induced damage. Consistently, in vivo silencing of either GATA3 or KMT2A prevented NCX3 upregulation and consequently the neuroprotective effect of preconditioning stimulus. The involvement of GATA3/KMT2A complex in neuroprotection elicited by ischemic preconditioning was further confirmed by in vitro experiments in which the knocking-down of GATA3 and KMT2A reverted the neuroprotection induced by NCX3 overexpression in cortical neurons exposed to anoxic preconditioning followed by oxygen and glucose deprivation plus reoxygenation. Conclusions: Collectively, our results revealed that GATA3/KMT2A complex epigenetically activates NCX3 gene transcription during ischemic preconditioning.

scholarly journals TRPV1 translocated to astrocytic membrane to promote migration and inflammatory infiltration thus promotes epilepsy after hypoxic ischemia in immature brain

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Xin Wang ◽  
Xing-Liang Yang ◽  
Wei-Lin Kong ◽  
Meng-Liu Zeng ◽  
Lin Shao ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Inflammatory Cytokines ◽  
Neuronal Excitability ◽  
Glucose Deprivation ◽  
Brain Electrical Activity ◽  
Inflammatory Infiltration ◽  
Hypoxic Ischemia ◽  
Pro Inflammatory Cytokines

Abstract Background Neonatal hypoxic-ischemic brain damage (HIBD), a leading cause of neonatal mortality, has intractable sequela such as epilepsy that seriously affected the life quality of HIBD survivors. We have previously shown that ion channel dysfunction in the central nervous system played an important role in the process of HIBD-induced epilepsy. Therefore, we continued to validate the underlying mechanisms of TRPV1 as a potential target for epilepsy. Methods Neonatal hypoxic ischemia and oxygen-glucose deprivation (OGD) were used to simulate HIBD in vivo and in vitro. Primarily cultured astrocytes were used to assess the expression of TRPV1, glial fibrillary acidic protein (GFAP), cytoskeletal rearrangement, and inflammatory cytokines by using Western blot, q-PCR, and immunofluorescence. Furthermore, brain electrical activity in freely moving mice was recorded by electroencephalography (EEG). TRPV1 current and neuronal excitability were detected by whole-cell patch clamp. Results Astrocytic TRPV1 translocated to the membrane after OGD. Mechanistically, astrocytic TRPV1 activation increased the inflow of Ca2+, which promoted G-actin polymerized to F-actin, thus promoted astrocyte migration after OGD. Moreover, astrocytic TRPV1 deficiency decreased the production and release of pro-inflammatory cytokines (TNF, IL-6, IL-1β, and iNOS) after OGD. It could also dramatically attenuate neuronal excitability after OGD and brain electrical activity in HIBD mice. Behavioral testing for seizures after HIBD revealed that TRPV1 knockout mice demonstrated prolonged onset latency, shortened duration, and decreased seizure severity when compared with wild-type mice. Conclusions Collectively, TRPV1 promoted astrocyte migration thus helped the infiltration of pro-inflammatory cytokines (TNF, IL-1β, IL-6, and iNOS) from astrocytes into the vicinity of neurons to promote epilepsy. Our study provides a strong rationale for astrocytic TRPV1 to be a therapeutic target for anti-epileptogenesis after HIBD.

scholarly journals A2B Adenosine Receptors: When Outsiders May Become an Attractive Target to Treat Brain Ischemia or Demyelination

2020 ◽  
Vol 21 (24) ◽  
pp. 9697
Author(s):  
Elisabetta Coppi ◽  
Ilaria Dettori ◽  
Federica Cherchi ◽  
Irene Bulli ◽  
Martina Venturini ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Brain Ischemia ◽  
Hippocampal Slices ◽  
Glucose Deprivation ◽  
Inflammatory Cells ◽  
Demyelinating Diseases ◽  
Receptor Subtype ◽  
Functional Impairments

Adenosine is a signaling molecule, which, by activating its receptors, acts as an important player after cerebral ischemia. Here, we review data in the literature describing A2BR-mediated effects in models of cerebral ischemia obtained in vivo by the occlusion of the middle cerebral artery (MCAo) or in vitro by oxygen-glucose deprivation (OGD) in hippocampal slices. Adenosine plays an apparently contradictory role in this receptor subtype depending on whether it is activated on neuro-glial cells or peripheral blood vessels and/or inflammatory cells after ischemia. Indeed, A2BRs participate in the early glutamate-mediated excitotoxicity responsible for neuronal and synaptic loss in the CA1 hippocampus. On the contrary, later after ischemia, the same receptors have a protective role in tissue damage and functional impairments, reducing inflammatory cell infiltration and neuroinflammation by central and/or peripheral mechanisms. Of note, demyelination following brain ischemia, or autoimmune neuroinflammatory reactions, are also profoundly affected by A2BRs since they are expressed by oligodendroglia where their activation inhibits cell maturation and expression of myelin-related proteins. In conclusion, data in the literature indicate the A2BRs as putative therapeutic targets for the still unmet treatment of stroke or demyelinating diseases.

scholarly journals Intravenous antagomiR-494 lessens brain-infiltrating neutrophils by increasing HDAC2-mediated repression of multiple MMPs in experimental stroke

2019 ◽  
Author(s):  
Fangfang Li ◽  
Haiping Zhao ◽  
Guangwen Li ◽  
Sijia Zhang ◽  
Rongliang Wang ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neuronal Damage ◽  
Neutrophil Migration ◽  
Glucose Deprivation ◽  
Neutrophil Infiltration ◽  
Predictive Biomarker ◽  
Experimental Stroke ◽  
Mmp Genes

Abstract Background: Neutrophil infiltration and phenotypic transformation are believed to contribute to neuronal damage and clinical outcome in ischemic stroke. Emerging evidence suggests that HDAC2 is an epigenetic regulator of inflammatory cells. Here, we investigated whether miR-494 affects HDAC2-mediated neutrophil infiltration and phenotypic shift. Methods: The miR-494 levels in neutrophils from AIS patients were detected by real-time PCR. C57BL/6J mice were subjected to transient middle cerebral artery occlusion, and the N1/N2 neutrophil shift was examined. Cortical neurons were subjected to oxygen-glucose deprivation and stimulated with supernatant from differently treated neutrophils or were cocultured with neutrophils; neuronal injury was detected, and ChIP-Seq was performed to clarify which genes are the binding targets of HDAC2. Finally, a transwell assay was conducted to examine neutrophil migration. Results: Compared to the control subjects, AIS patients had increased neutrophil expression of miR-494, and in AIS patients, elevated miR-494 expression in neutrophils was a predictor of worse neurological outcomes. MiR-494 correlates with the upregulation of adhesion molecules in neutrophils of AIS patients. Systemically administered antagomiR-494 partly shifts neutrophils into the N2 phenotype in MCAO mice. AntagomiR-494-treated neutrophils exert a neuroprotective role in vitro. ChIP-seq revealed that HDAC2 targets multiple MMP genes in neutrophils of AIS patients. Further in vitro and in vivo experiments showed that antagomiR-494 repressed expression of MMP genes, including MMP7, MMP10, MMP13, and MMP16, to reduce the number of brain-infiltrating neutrophils by regulating HDAC2. Conclusion: MiR-494 may serve as an alternative predictive biomarker of the outcome of AIS patients, and antagomiR-494 treatment decreased the expression of multiple MMPs and the infiltration of neutrophils partly by targeting HDAC2.

scholarly journals Cerebroprotective effect of xantohumol sensu experimental stroke model: study design and preliminary results

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Aigul Saitgareyeva ◽  
Leyla Akhmadeyeva
Keyword(s):  
Ischemic Stroke ◽  
Cortical Neurons ◽  
Glucose Deprivation ◽  
Experimental Stroke ◽  
Control Group ◽  
Stroke Model ◽  
Sprague Dawley ◽  
Preliminary Results

The objective of our study was to evaluate the cerebroprotective effect of xanthohumol (ХN) on experimental models of acute ischemic stroke in vivo and in vitro. Materials and methods. We used middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD) as in vivo and in vitro models. Our study subjects were Sprague-Dawley rats, which were randomly assigned to three groups: the control group and two MCAO groups with and without XN. The primary culture of cortical neurons was obtained from newborn rats. We employed the Bederson test and the corner test to evaluate neurological disorders. Results. The preliminary results indicated a possible cerebroprotective effect of XN in an ischemic stroke model. Conclusion. Preventive administration of XN before cerebral ischemia in an experiment can effectively reduce the volume of cerebral infarction and improve neurologic deficit 24 hours after MCAO.

Background Activity Regulates Excitability of Rat Hippocampal CA1 Pyramidal Neurons by Adaptation of a K+ Conductance

2006 ◽  
Vol 95 (3) ◽  
pp. 2007-2012 ◽  
Author(s):  
Ingrid van Welie ◽  
Johannes A. van Hooft ◽  
Wytse J. Wadman
Keyword(s):  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Dynamic Range ◽  
Background Activity ◽  
Hippocampal Slices ◽  
Synaptic Activity ◽  
Input Output ◽  
Ca1 Pyramidal Neurons

In the in vivo brain background synaptic activity has a strong modulatory influence on neuronal excitability. Here we report that in rat hippocampal slices, blockade of endogenous in vitro background activity results in an increased excitability of CA1 pyramidal neurons within tens of minutes. The increase in excitability constitutes a leftward shift in the input–output relationship of pyramidal neurons, indicating a reduced threshold for the induction of action potentials. The increase in excitability results from an adaptive decrease in a sustained K+ conductance, as recorded from somatic cell–attached patches. After 20 min of blockade of background activity, the mean sustained K+ current amplitude in somatic patches was reduced to 46 ± 9% of that in time-matched control patches. Blockade of background activity did not affect fast Na+ conductance. Together, these results suggests that the reduction in K+ conductance serves as an adaptive mechanism to increase the excitability of CA1 pyramidal neurons in response to changes in background activity such that the dynamic range of the input–output relationship is effectively maintained.

scholarly journals HIF1α Signaling in the Endogenous Protective Responses after Neonatal Brain Hypoxia-Ischemia

2018 ◽  
Vol 40 (5-6) ◽  
pp. 617-626 ◽  
Author(s):  
Xiao Liang ◽  
Xuemei Liu ◽  
Fuxin Lu ◽  
Yunling Zhang ◽  
Xiangning Jiang ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Target Genes ◽  
Apoptotic Cell ◽  
Glucose Deprivation ◽  
Brain Maturation ◽  
Maturation Stage ◽  
Hypoxia Ischemia

Hypoxia-inducible factor 1α (HIF1α) is a key regulator of oxygen homeostasis, and its target genes mediate adaptive, protective, and pathological processes. The role of HIF1α in neuronal survival is controversial and the brain maturation stage is important in determining its function in brain ischemia or hypoxia-ischemia (HI). In this study, we used neuron-specific HIF1α knockout mice at postnatal day 9 (P9), and immature cortical neurons (days 7–8 in vitro) treated with the HIF1α inhibitor 2-methoxyestradiol (2ME2) or stabilizer dimethyloxalylglycine (DMOG), to examine the function of neuronal HIF1α in neonatal HI in vivo (Vannucci model) and in vitro (oxygen glucose deprivation, OGD). Inhibition of HIF1α with 2ME2 in primary neurons or deletion of neuronal HIF1α in P9 mice increased both necrotic and apoptotic cell death following HI, as evaluated by the protein levels of 145/150-kDa and 120-kDa spectrin breakdown products 24 h after HI. DMOG attenuated neuronal death right after OGD. Acute pharmacological manipulation of HIF1α synchronously regulated the expression of its targets, vascular endothelial growth factor (VEGF) and erythropoietin (Epo), in the same manner. The in vivo findings agree with our previous data using the same HIF1α-deficient mice at an earlier age. This study confirms the role of neuronal HIF1α signaling in the endogenous protective responses following HI in the developing brain.

scholarly journals Neuroprotective Role of Lactate after Cerebral Ischemia

2009 ◽  
Vol 29 (11) ◽  
pp. 1780-1789 ◽  
Author(s):  
Carole Berthet ◽  
Hongxia Lei ◽  
Jonathan Thevenet ◽  
Rolf Gruetter ◽  
Pierre J Magistretti ◽  
...  
Keyword(s):  
Hippocampal Slices ◽  
Glucose Deprivation ◽  
Lesion Size ◽  
Artery Occlusion ◽  
Neurologic Outcome ◽  
Moderate Increase ◽  
Cerebral Artery Occlusion

It is well established that lactate can be used as an energy substrate by the brain by conversion to pyruvate and a subsequent oxidation in the mitochondria. Knowing the need for readily metabolizable substrates directly after ischemia and the protective effect of lactate after excitotoxicity, the aim of this study was to investigate whether lactate administration directly after ischemia could be neuroprotective. In vitro, the addition of 4 mmol/L l-lactate to the medium of rat organotypic hippocampal slices, directly after oxygen and glucose deprivation (OGD), protected against neuronal death, whereas a higher dose of 20 mmol/L was toxic. In vivo, after middle cerebral artery occlusion in the mouse, an intracerebroventricular injection of 2 μL of 100 mmol/L l-lactate, immediately after reperfusion, led to a significant decrease in lesion size, which was more pronounced in the striatum, and an improvement in neurologic outcome. A later injection 1 h after reperfusion did not reduce lesion size, but significantly improved neurologic outcome, which is an important point in the context of a potential clinical application. Therefore, a moderate increase in lactate after ischemia may be a therapeutic tool.

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