Wild-type PINK1 prevents basal and induced neuronal apoptosis, a protective effect abrogated by Parkinson disease-related mutations.
Mutations in the PTEN-induced kinase 1 (PINK1) gene have recently been implicated in autosomal recessive early onset Parkinson Disease (1, 2). To investigate the role of PINK1 in neurodegeneration, we designed human and murine neuronal cell lines expressing either wild-type PINK1 or PINK1 bearing a mutation associated with Parkinson Disease. We show that under basal and staurosporine-induced conditions, the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive cells was lower in wild-type PINK1 expressing SH-SY5Y cells than in mock-transfected cells. This phenotype was due to a PINK1-mediated reduction in cytochrome c release from mitochondria, which prevents subsequent caspase-3 activation. We show that overexpression of wild-type PINK1 strongly reduced both basal and staurosporine-induced caspase 3 activity. Overexpression of wild-type PINK1 also reduced the levels of cleaved caspase-9, caspase-3, caspase-7, and activated poly(ADP-ribose) polymerase under both basal and staurosporine-induced conditions. In contrast, Parkinson disease-related mutations and a kinase-inactive mutation in PINK1 abrogated the protective effect of PINK1. Together, these results suggest that PINK1 reduces the basal neuronal pro-apoptotic activity and protects neurons from staurosporine-induced apoptosis. Loss of this protective function may therefore underlie the degeneration of nigral dopaminergic neurons in patients with PINK1 mutations.
Petit
Agnes
A
Centre for Research in Neurodegenerative Diseases, Department of Medicine (Neurology), University of Toronto, Toronto, Ontario M5S 3H2, Canada.
Kawarai
Toshitaka
T
Paitel
Erwan
E
Sanjo
Nobuo
N
Maj
Mary
M
Scheid
Michael
M
Chen
Fusheng
F
Gu
Yongjun
Y
Hasegawa
Hiroshi
H
Salehi-Rad
Shabnam
S
Wang
Linda
L
Rogaeva
Ekaterina
E
Fraser
Paul
P
Robinson
Brian
B
St George-Hyslop
Peter
P
Tandon
Anurag
A
D000368:Aged; D000595:Amino Acid Sequence; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D018929:Cell Culture Techniques; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D004252:DNA Mutational Analysis; D005347:Fibroblasts; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology; D010300:Parkinson Disease / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics* / Q000502:physiology*; D011954:Receptors, Dopamine / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099202:PTEN-Induced Putative Kinase
D053148:Caspase 3; D020169:Caspases; D045304:Cytochromes c; D011494:Protein Kinases; D011954:Receptors, Dopamine; D000099202:PTEN-Induced Putative Kinase; C505407:CASP3 protein, human