Single and double strand DNA breaks activate the nuclear enzyme poly(ADP-ribose) polymerase (PARP) which catalyzes the cleavage of NAD+ into nicotinamide and ADP-ribose and synthesizes branched polymers of ADP-ribose (PAR) on nuclear acceptor proteins. Although this process ordinarily assists DNA repair and long-term DNA stabilization, severe oxidative damage seen in models of stroke and NMDA excitotoxicity is thought to lead to over-activation of PARP and subsequent neuronal cell death by a mechanism that does not produce classical apoptotic morphology. Previous work demonstrates that NMDA excitotoxicity can produce a novel form of programmed cell death that is independent of caspase activation and that involves the translocation of apoptosis inducing factor (AIF) from mitochondria to the nucleus. This translocation requires PARP activation and may depend on a PAR signaling mechanism in oxidatively stressed cells. Preliminary data shows that PARP2 gene deletion, like PARP1 gene deletion, confers robust ischemic protection. The overall goal of this project is to investigate the potential molecular mechanisms by which activation of PARP promotes cell death in experimental stroke. The time course ofAIF translocation to the nucleus will be contrasted after different durations of transient focal cerebral ischemia in ischemic core and border regions. The dependency of AIF translocation on neuronal generation of nitric oxide and on subsequent activation of PARP1 and PARP2 will be determined with appropriate knockout animals and pharmacological inhibitors. The role of AIF in focal ischemic injury will be determined using conditional AIF knockout and stable AIF knockdown animal strains. Because AIF mediated cell death in C. elegans involves DNA fragmentation by endonuclease G, the role of this endonuclease in ischemic injury will be assessed in endonuclease G knockout animals. Finally, the role of PAR in signaling AIF translocation will be evaluated by manipulating PAR catabolism in animals with increased and decreased expression of PAR glycohydrolase (PARG). Preliminary evidence showing a decrease in infarct volume with PARG over-expression and an increase in infarct volume with PARG knockdown supports a role of PAR in the signaling process. Therefore, the proposed experiments will generate new insights into the potential role of a novel form of programmed cell death in vivo that may be critical during the evolution of injury from stroke.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Program Projects (P01)
Project #
Application #
Study Section
National Institute of Neurological Disorders and Stroke Initial Review Group (NSD)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Johns Hopkins University
United States
Zip Code
Fatokun, A A; Liu, J O; Dawson, V L et al. (2013) Identification through high-throughput screening of 4'-methoxyflavone and 3',4'-dimethoxyflavone as novel neuroprotective inhibitors of parthanatos. Br J Pharmacol 169:1263-78
Wang, Yingfei; Kim, No Soo; Haince, Jean-Francois et al. (2011) Poly(ADP-ribose) (PAR) binding to apoptosis-inducing factor is critical for PAR polymerase-1-dependent cell death (parthanatos). Sci Signal 4:ra20
Andrabi, Shaida A; Kang, Ho Chul; Haince, Jean-Fran├žois et al. (2011) Iduna protects the brain from glutamate excitotoxicity and stroke by interfering with poly(ADP-ribose) polymer-induced cell death. Nat Med 17:692-9
Kang, Ho Chul; Lee, Yun-Il; Shin, Joo-Ho et al. (2011) Iduna is a poly(ADP-ribose) (PAR)-dependent E3 ubiquitin ligase that regulates DNA damage. Proc Natl Acad Sci U S A 108:14103-8
Li, Xiaoling; Klaus, Judith A; Zhang, Jian et al. (2010) Contributions of poly(ADP-ribose) polymerase-1 and -2 to nuclear translocation of apoptosis-inducing factor and injury from focal cerebral ischemia. J Neurochem 113:1012-22
Xu, Zhenfeng; Zhang, Jian; David, Karen K et al. (2010) Endonuclease G does not play an obligatory role in poly(ADP-ribose) polymerase-dependent cell death after transient focal cerebral ischemia. Am J Physiol Regul Integr Comp Physiol 299:R215-21
Kishimoto, Koji; Li, Rung-Chi; Zhang, Jian et al. (2010) Cytosolic phospholipase A2 alpha amplifies early cyclooxygenase-2 expression, oxidative stress and MAP kinase phosphorylation after cerebral ischemia in mice. J Neuroinflammation 7:42
Wang, Yingfei; Kim, No S; Li, Xiaoling et al. (2009) Calpain activation is not required for AIF translocation in PARP-1-dependent cell death (parthanatos). J Neurochem 110:687-96
Yu, Seong-Woon; Wang, Yingfei; Frydenlund, Didrik S et al. (2009) Outer mitochondrial membrane localization of apoptosis-inducing factor: mechanistic implications for release. ASN Neuro 1:
Wang, Yingfei; Dawson, Valina L; Dawson, Ted M (2009) Poly(ADP-ribose) signals to mitochondrial AIF: a key event in parthanatos. Exp Neurol 218:193-202

Showing the most recent 10 out of 27 publications