Attenuation of neurotoxicity in cortical cultures and hippocampal slices from E2F1 knockout mice

Gendron, Tania F.; Mealing, Geoff; Paris, James; Lou, Allison; Edwards, Andrei; Hou, Sheng T.; MacManus, J. P.; Hakim, Antoine M.; Morley, Paul

doi:10.1046/j.1471-4159.2001.00423.x

Cited by 53 publications

(44 citation statements)

References 31 publications

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“…E2F1 has been demonstrated to promote apoptosis in postmitotic neurons including cerebellar granule neurons (O'Hare et al, 2000;Gendron et al, 2001;Liu and Greene, 2001b). Consistent with these observations, we found that the dominant interfering form of E2F (E2F-Rb), when expressed in granule neurons, blocked the ability of KCl withdrawal to induce apoptosis (Fig.…”

Section: E2f Mediates Activity Deprivationinduced Cdc2 Transcription supporting

confidence: 87%

The E2F–Cdc2 Cell-Cycle Pathway Specifically Mediates Activity Deprivation-Induced Apoptosis of Postmitotic Neurons

Konishi

Bonni

2003

J. Neurosci.

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Neuronal apoptosis plays a critical role in the normal development of the mammalian brain and is thought to contribute to the pathogenesis of several neurologic disorders. However, the intracellular mechanisms underlying apoptosis of neurons remain incompletely understood. In the present study, we characterized a cell-cycle-based mechanism by which neuronal activity deprivation induces apoptosis of postmitotic neurons. Activity deprivation, but not growth factor withdrawal, was found to induce Cdc2 expression and consequent Cdc2-mediated apoptosis in granule neurons of the developing rat cerebellum. We found that activity deprivation induces cdc2 transcription in neurons via an E2F-binding element (EBE) within the cdc2 promoter. The transcription factor E2F1 that is expressed in granule neurons was found in DNA binding assays to bind to the EBE of the cdc2 gene. In chromatin immunoprecipitation analysis, endogenous E2F1 forms a complex with the promoter of the endogenous cdc2 gene in granule neurons, indicating that endogenous E2F1 is poised to activate transcription of the endogenous cdc2 gene in neurons. Consistent with this conclusion, a dominant interfering form of E2F, when expressed in granule neurons, blocked activity deprivation-induced cdc2 transcription. In other experiments, we found that the expression of E2F1 in granule neurons induces Cdc2 expression and promotes neuronal apoptosis via the activation of Cdc2. Remarkably, in contrast to inducing the E2F-mediated expression and activation of Cdc2 in granule neurons, activity deprivation fails to stimulate the expression of E2F-target genes that trigger DNA synthesis and replication. Together, our findings define a novel apoptotic mechanism whereby E2F selectively couples an activity deprivation-induced signal to cdc2 transcription in the absence of stimulating DNA synthesis and thus culminating in Cdc2-mediated apoptosis of postmitotic neurons.

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Section: E2f Mediates Activity Deprivationinduced Cdc2 Transcription supporting

confidence: 87%

The E2F–Cdc2 Cell-Cycle Pathway Specifically Mediates Activity Deprivation-Induced Apoptosis of Postmitotic Neurons

Konishi

Bonni

2003

J. Neurosci.

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“…It has been proposed that Cdk enzymes that normally regulate cell cycle progression in neurons may participate in the modulation of programmed cell death (Giardina et al, 1998;Hidetoshi and Chiba, 2001). This hypothesis is supported by previous studies in which the death of neurons, evoked by different stimuli such as serum and potassium deprivation (O'Hare et al, 2000;Martín-Romero et al, 2001;Trinh et al, 2001), excitotoxic treatment (Giardina et al, 1998;Park et al, 2000;Verdaguer et al, 2002b), and ␤-amyloid (Copani et al, 1999;Caricasole et al, 2003) and DNA damage agents (Gendron et al, 2001), is regulated, in part, by activation of cyclin-dependent kinases. Furthermore, there is evidence of the expression of cell cycle-related proteins in the brain of patients who have been suffering different neurodegenerative diseases (Jordan-Sciutto, 2002a,b;Yang et al, 2001Yang et al, , 2003.…”

Section: Discussionsupporting

confidence: 71%

Inhibition of Cell Cycle Pathway by Flavopiridol Promotes Survival of Cerebellar Granule Cells after an Excitotoxic Treatment

Verdaguer

Jiménez

Canudas³

et al. 2003

J Pharmacol Exp Ther

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Kainic acid (KA)-induced neuronal damage and the protective effects of flavopiridol were studied in primary cultures of rat cerebellar granule cells (CGNs). When neurons were treated with 500 M KA, the percentage of cells with condensed nuclei measured by nuclear counting increased by up to 55%. After flavopiridol treatment, an antitumoral drug that is a broad inhibitor of cyclin-dependent kinases, the percentage of condensed nuclei decreased by up to 26%. Furthermore, this KA-mediated cell death was only partially dependent on the activation of the initiator caspase-9 and the effector caspases-3 and -6. This argues for a minor role of caspases in the intracellular pathway leading to KA-induced programmed cell death in CGNs. We examined the possible implication of cell cycle proteins in KA-induced neurotoxicity. We found an increase in the expression of proliferating cell nuclear antigen and E2F-1, two proteins implicated in S-phase, by Western blot. KA increased bromodeoxyuridine incorporation in CGNs, a marker of cell proliferation, and flavopiridol attenuated this effect. These results indicated that flavopiridol decreased the expression of cell cycle markers in CGNs after KA treatment. Flavopiridol might thus be used as a preventive agent against neurodegenerative diseases associated with cell cycle activation.

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“…Increasing OGD duration to 100 min in a similar mixed culture also did not give rise to any propidium-stained apoptotic cells [56]. Studies utilising caspase activation as an indication of apoptotic cell death, have also failed to demonstrate any increases in activity after either 60 [53] or 150 min [57] exposure to OGD. Another study which analysed apoptotic cell death using TUNEL combined with morphological analysis after 30-90 min exposure to OGD, found only a tiny proportion of the cells (0.05 %) underwent apoptosis by 48 h [58].…”

Section: Discussionmentioning

confidence: 89%

Apoptosis is not an invariable component of in vitro models of cortical cerebral ischaemia

et al. 2004

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Characterising the mechanisms of cell death following focal cerebral ischaemia has been hampered by a lack of an in vitro assay emulating both the apoptotic and necrotic features observed in vivo. The present study systematically characterised oxygen-glucose-deprivation (OGD) in primary rat cortical neurones to establish a reproducible model with components of both cell-death endpoints. OGD induced a time-dependent reduction in cell viability, with 80% cell death occurring 24 h after 3 h exposure to 0% O 2 and 0.5 mM glucose. Indicative of a necrotic component to OGDinduced cell death, N-methyl-D-aspartate (NMDA) receptor inhibition with MK-801 attenuated neuronal loss by 60%. The lack of protection by the caspase inhibitors DEVD-CHO and z-VAD-fmk suggested that under these conditions neurones did not die by an apoptotic mechanism. Moderating the severity of the insult by decreasing OGD exposure to 60 min did not reduce the amount of necrosis, but did induce a small degree of apoptosis (a slight reduction in cell death was observed in the presence of 10 µM DEVD-CHO). In separate experiments purported to enhance the apoptotic component, cells were gradually deprived of O 2 , exposed to 4% O 2 (as opposed to 0%) during the OGD period, or maintained in serum-containing media throughout. While NMDA receptor antagonism significantly reduced cortical cell death under all conditions, a caspase-inhibitor sensitive component of cell death was not uncovered. These studies suggest that OGD of cultured cortical cells models the excitotoxic, but not the apoptotic component of cell death observed in vivo.

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Attenuation of neurotoxicity in cortical cultures and hippocampal slices from E2F1 knockout mice

Cited by 53 publications

References 31 publications

The E2F–Cdc2 Cell-Cycle Pathway Specifically Mediates Activity Deprivation-Induced Apoptosis of Postmitotic Neurons

The E2F–Cdc2 Cell-Cycle Pathway Specifically Mediates Activity Deprivation-Induced Apoptosis of Postmitotic Neurons

Inhibition of Cell Cycle Pathway by Flavopiridol Promotes Survival of Cerebellar Granule Cells after an Excitotoxic Treatment

Apoptosis is not an invariable component of in vitro models of cortical cerebral ischaemia

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