Regulation of ischemic neuronal death by E2F4-p130 protein complexes.
Inappropriate activation of cell cycle proteins, in particular cyclin D/Cdk4, is implicated in neuronal death induced by various pathologic stresses, including DNA damage and ischemia. Key targets of Cdk4 in proliferating cells include members of the E2F transcription factors, which mediate the expression of cell cycle proteins as well as death-inducing genes. However, the presence of multiple E2F family members complicates our understanding of their role in death. We focused on whether E2F4, an E2F member believed to exhibit crucial control over the maintenance of a differentiated state of neurons, may be critical in ischemic neuronal death. We observed that, in contrast to E2F1 and E2F3, which sensitize to death, E2F4 plays a crucial protective role in neuronal death evoked by DNA damage, hypoxia, and global ischemic insult both in vitro and in vivo. E2F4 occupies promoter regions of proapoptotic factors, such as B-Myb, under basal conditions. Following stress exposure, E2F4-p130 complexes are lost rapidly along with the presence of E2F4 at E2F-containing B-Myb promoter sites. In contrast, the presence of E2F1 at B-Myb sites increases with stress. Furthermore, B-Myb and C-Myb expression increases with ischemic insult. Taken together, we propose a model by which E2F4 plays a protective role in neurons from ischemic insult by forming repressive complexes that prevent prodeath factors such as Myb from being expressed.
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Grace O
GO
Iyirhiaro
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Yi
Y
Zhang
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Carmen
C
Estey
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Michael J
MJ
O'Hare
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Farzaneh
F
Safarpour
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Mohammad
M
Parsanejad
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Suzi
S
Wang
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Elizabeth
E
Abdel-Messih
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Steve M
SM
Callaghan
the Department of Molecular Virology, Immunology, and Medical Genetics, Neurological Surgery, College of Medicine, The Ohio State University, Columbus, Ohio 43210.
Matthew J
MJ
During
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and.
Ruth S
RS
Slack
From the Department of Cellular and Molecular Medicine and Neuroscience, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada and dpark@uottawa.ca.
David S
DS
Park
D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D050704:E2F4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017208:Rats, Wistar; D050717:Retinoblastoma-Like Protein p130 / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D018797:Cell Cycle Proteins; D050704:E2F4 Transcription Factor; C499306:Mybl2 protein, mouse; D050717:Retinoblastoma-Like Protein p130; D015534:Trans-Activators
Apoptosis; Cardiovascular Disease; Cell Biology; Cell Cycle; Cell Death; Cyclin-dependent Kinase (Cdk); E2F Transcription Factor; Hypoxia; Ischemia; Stroke