title: Glutaredoxin 1 protects dopaminergic cells by increased protein glutathionylation in experimental Parkinson's disease.
abstract: OBJECTIVE
  Chronic exposure to environmental toxicants, such as paraquat, has been suggested as a risk factor for Parkinson's disease (PD). Although dopaminergic cell death in PD is associated with oxidative damage, the molecular mechanisms involved remain elusive. Glutaredoxins (GRXs) utilize the reducing power of glutathione to modulate redox-dependent signaling pathways by protein glutathionylation. We aimed to determine the role of GRX1 and protein glutathionylation in dopaminergic cell death.
  
  
  RESULTS
  In dopaminergic cells, toxicity induced by paraquat or 6-hydroxydopamine (6-OHDA) was inhibited by GRX1 overexpression, while its knock-down sensitized cells to paraquat-induced cell death. Dopaminergic cell death was paralleled by protein deglutathionylation, and this was reversed by GRX1. Mass spectrometry analysis of immunoprecipitated glutathionylated proteins identified the actin binding flightless-1 homolog protein (FLI-I) and the RalBP1-associated Eps domain-containing protein 2 (REPS2/POB1) as targets of glutathionylation in dopaminergic cells. Paraquat induced the degradation of FLI-I and REPS2 proteins, which corresponded with the activation of caspase 3 and cell death progression. GRX1 overexpression reduced both the degradation and deglutathionylation of FLI-I and REPS2, while stable overexpression of REPS2 reduced paraquat toxicity. A decrease in glutathionylated proteins and REPS2 levels was also observed in the substantia nigra of mice treated with paraquat.
  
  
  METHODS
  We have identified novel protein targets of glutathionylation in dopaminergic cells and demonstrated the protective role of GRX1-mediated protein glutathionylation against paraquat-induced toxicity.
  
  
  CONCLUSIONS
  These results demonstrate a protective role for GRX1 and increased protein glutathionylation in dopaminergic cell death induced by paraquat, and identify a novel protective role for REPS2.
authors: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
authors: Humberto
authors: H
authors: Rodriguez-Rocha
authors: Aracely
authors: A
authors: Garcia Garcia
authors: Laura
authors: L
authors: Zavala-Flores
authors: Sumin
authors: S
authors: Li
authors: Nandakumar
authors: N
authors: Madayiputhiya
authors: Rodrigo
authors: R
authors: Franco
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D005434:Flow Cytometry; D054477:Glutaredoxins / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D020734:Parkinsonian Disorders / Q000235:genetics / Q000378:metabolism*
chemical_list: D054477:Glutaredoxins; D005978:Glutathione