Identification of poly-ADP-ribosylated mitochondrial proteins after traumatic brain injury.
Poly-ADP-ribosylation is a post-translational modification performed by poly(ADP-ribose) polymerases (PARP), involved in many diverse cellular functions including DNA repair, transcription, and long-term potentiation. Paradoxically, PARP over-activation under pathologic conditions including traumatic brain injury (TBI) results in cell death. We previously demonstrated that intra-mitochondrial poly-ADP-ribosylation occurs following excitotoxic and oxidative injury in vitro. Here we sought to identify mitochondrial proteins modified by poly-ADP-ribosylation after TBI in vivo. Poly-ADP-ribosylation within mitochondria from injured brain after experimental TBI in rats was first verified using western blot and immuno-electron microscopy. Poly-ADP-ribosylated mitochondrial proteins identified using a targeted proteomic approach included voltage-dependent anion channel-1, mitofilin, mitochondrial stress proteins, and the electron transport chain components F1F0 ATPase, cytochrome c oxidase, and cytochrome c reductase. To examine the functional consequences of mitochondrial poly-ADP-ribosylation, isolated rat brain mitochondria were exposed to conditions of nitrosative stress known to activate PARP. PARP activation-induced reductions in State 3 respiration were prevented by the PARP-1 inhibitor 5-iodo-6-amino-1,2-benzopyrone or exogenous poly(ADP-ribose) glycohydrolase. As the effects of PARP activation on mitochondrial respiration appear regulated by poly(ADP-ribose) glycohydrolase, a direct effect of poly-ADP-ribosylation on electron transport chain function is suggested. These findings may be of relevance to TBI and other diseases where mitochondrial dysfunction occurs.
Lai
Yichen
Y
Department of Critical Care Medicine, the Safar Center for Resuscitation Research and the Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Chen
Yaming
Y
Watkins
Simon C
SC
Nathaniel
Paula D
PD
Guo
Fengli
F
Kochanek
Patrick M
PM
Jenkins
Larry W
LW
Szabó
Csaba
C
Clark
Robert S B
RS
D000818:Animals; D001921:Brain / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology; D019069:Cell Respiration; D004579:Electron Transport; D008928:Mitochondria / Q000378:metabolism; D028361:Mitochondrial Diseases / Q000378:metabolism* / Q000473:pathology; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D000071137:Poly (ADP-Ribose) Polymerase-1; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D024101:Mitochondrial Proteins; D009243:NAD; D011064:Poly Adenosine Diphosphate Ribose; C499322:Parp1 protein, rat; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D009584:Nitrogen