Silencing DJ-1 reveals its contribution in paraquat-induced autophagy.
The role of autophagy as a survival strategy of cells constitutes an emerging topic in the study of the pathogenesis of several diseases with autophagic changes being described in a number of age-related neurodegenerative disorders, including Parkinson's disease (PD). Although the etiology of PD is still unknown, both environmental (for example, paraquat exposure) and genetic factors have been investigated as putative causes of the disease. In the latter case, mutations or changes in the protein DJ-1 have been reported to be associated with autosomal recessive, early-onset parkinsonism. In this paper we established a model system to study the involvement of the DJ-1 protein in paraquat-induced autophagy. When human neuroblastoma SH-SY5Y cells were transfected with DJ-1-specific small interfering RNAs and exposed to paraquat, we observed (i) sensitization additive with paraquat-induced apoptotic cell death, (ii) inhibition of the cytoplasmic accumulation of autophagic vacuoles as well as the recruitment of LC3 fusion protein to the vacuoles, (iii) exacerbation of apoptotic cell death in the presence of the autophagy inhibitor 3-methyladenine, and (iv) an increase in mammalian target of rapamycin phosphorylation. Taken together, these findings suggest an active role for DJ-1 in the autophagic response produced by paraquat, providing evidence for the role of PD-related proteins in the autophagic degradation pathway, a factor that should be considered in the design of potential therapies for the treatment of the disease.
CIBER sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, EU Enfermería y Terapia Ocupacional, Universidad de Extremadura, Cáceres, Spain. rosapolo@unex.es
Rosa
R
González-Polo
Mireia
M
Niso-Santano
José M
JM
Morán
Miguel A
MA
Ortiz-Ortiz
José M
JM
Bravo-San Pedro
Germán
G
Soler
José M
JM
Fuentes
D000704:Analysis of Variance; D017304:Annexin A5 / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D005434:Flow Cytometry / Q000379:methods; D006540:Herbicides / Q000494:pharmacology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009447:Neuroblastoma / Q000473:pathology; D015513:Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010269:Paraquat / Q000494:pharmacology*; D000071617:Protein Deglycase DJ-1; D034741:RNA, Small Interfering / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection; D014617:Vacuoles / Q000187:drug effects / Q000473:pathology
D017304:Annexin A5; D006540:Herbicides; D047908:Intracellular Signaling Peptides and Proteins; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D015513:Oncogene Proteins; D034741:RNA, Small Interfering; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1; D010269:Paraquat