Inhibition of E2F1/CDK1 pathway attenuates neuronal apoptosis in vitro and confers neuroprotection after spinal cord injury in vivo

Junfang Wu*, Giorgi Kharebava, Chunshu Piao, Bogdan A. Stoica, Michael Dinizo, Boris Sabirzhanov, Marie Hanscom, Kelsey Guanciale, Alan I. Faden

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Apoptosis of post-mitotic neurons plays a significant role in secondary tissue damage following traumatic spinal cord injury (SCI). Activation of E2F1-dependent transcription promotes expression of pro-apoptotic factors, including CDK1; this signal transduction pathway is believed to represent an important mechanism for the physiological or pathological neuronal cell death. However, a specific role for this pathway in neuronal apoptosis induced by SCI has not yet been reported. Here we demonstrate up-regulation of the E2F1/CDK1 pathway that is associated with neuronal apoptosis following impact SCI in rats. Expression of E2F1 and CDK1 were robustly up-regulated as early as 15 min after injury and sustained until 3 days post-injury. CDK1 activity and E2F1 downstream targets bim and c-Myb were significantly increased after SCI. Activation of E2F1/CDK1 signaling also was associated with death of neurons in vitro; this was attenuated by shRNA knockdown or pharmacological inhibition of the E2F1/CDK1 pathway. CR8, a novel and potent CDK1 inhibitor, blocked apoptosis of primary cortical neurons at low-micromolar concentrations. Moreover, SCI-induced up-regulation of E2F1/CDK1 and associated neuronal apoptosis was significantly attenuated by systemic injection of CR8 (1 mg/kg, i.p.) at 5 min after injury. CR8 significantly decreased posttraumatic elevation of biochemical markers of apoptosis, such as products of caspase-3 and α-fodrin cleavage, as well as neuronal cell death, as indicated by TUNEL staining. Importantly, CR8 treatment also increased the number of surviving neurons at 5 weeks after injury. Together, these findings indicate that activation of the E2F1/CDK1 pathway contributes to the pathophysiology of SCI and that selective inhibition of this signaling cascade may represent an attractive therapeutic strategy.

Original languageEnglish (US)
Article numbere42129
JournalPloS one
Volume7
Issue number7
DOIs
StatePublished - Jul 25 2012

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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