title: Poly(ADP-ribose) (PAR) polymer is a death signal.
abstract: Excessive activation of the nuclear enzyme, poly(ADP-ribose) polymerase-1 (PARP-1) plays a prominent role in various of models of cellular injury. Here, we identify poly(ADP-ribose) (PAR) polymer, a product of PARP-1 activity, as a previously uncharacterized cell death signal. PAR polymer is directly toxic to neurons, and degradation of PAR polymer by poly(ADP-ribose) glycohydrolase (PARG) or phosphodiesterase 1 prevents PAR polymer-induced cell death. PARP-1-dependent, NMDA excitotoxicity of cortical neurons is reduced by neutralizing antibodies to PAR and by overexpression of PARG. Neuronal cultures with reduced levels of PARG are more sensitive to NMDA excitotoxicity than WT cultures. Transgenic mice overexpressing PARG have significantly reduced infarct volumes after focal ischemia. Conversely, mice with reduced levels of PARG have significantly increased infarct volumes after focal ischemia compared with WT littermate controls. These results reveal PAR polymer as a signaling molecule that induces cell death and suggests that interference with PAR polymer signaling may offer innovative therapeutic approaches for the treatment of cellular injury.
authors.affiliation: Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Shaida A
authors.initials: SA
authors.lastname: Andrabi
authors.forename: No Soo
authors.initials: NS
authors.lastname: Kim
authors.forename: Seong-Woon
authors.initials: SW
authors.lastname: Yu
authors.forename: Hongmin
authors.initials: H
authors.lastname: Wang
authors.forename: David W
authors.initials: DW
authors.lastname: Koh
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Judith A
authors.initials: JA
authors.lastname: Klaus
authors.forename: Takashi
authors.initials: T
authors.lastname: Otsuka
authors.forename: Zhizheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Koehler
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Hurn
authors.forename: Guy G
authors.initials: GG
authors.lastname: Poirier
authors.forename: Valina L
authors.initials: VL
authors.lastname: Dawson
authors.forename: Ted M
authors.initials: TM
authors.lastname: Dawson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D051379:Mice; D008970:Molecular Weight; D009474:Neurons / Q000187:drug effects; D011064:Poly Adenosine Diphosphate Ribose / Q000737:chemistry / Q000633:toxicity*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011108:Polymers / Q000737:chemistry / Q000633:toxicity*; D015398:Signal Transduction
chemical_list: D011108:Polymers; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases