Mutant Pink1 induces mitochondrial dysfunction in a neuronal cell model of Parkinson's disease by disturbing calcium flux.
Parkinson's disease (PD) is characterized by accumulation of alpha-synuclein (alpha-syn) and degeneration of neuronal populations in cortical and subcortical regions. Mitochondrial dysfunction has been considered a potential unifying factor in the pathogenesis of the disease. Mutations in genes linked to familial forms of PD, including SNCA encoding alpha-syn and Pten-induced putative kinase 1 (PINK1), have been shown to disrupt mitochondrial activity. We investigated the mechanisms through which mutant Pink1 might disrupt mitochondrial function in neuronal cells with alpha-syn accumulation. For this purpose, a neuronal cell model of PD was infected with virally-delivered Pink1, and was analyzed for cell survival, mitochondrial activity and calcium flux. Mitochondrial morphology was analyzed by confocal and electron microscopy. These studies showed that mutant (W437X) but not wildtype Pink1 exacerbated the alterations in mitochondrial function promoted by mutant (A53T) alpha-syn. This effect was associated with increased intracellular calcium levels. Co-expression of both mutant Pink1 and alpha-syn led to alterations in mitochondrial structure and neurite outgrowth that were partially ameliorated by treatment with cyclosporine A, and completely restored by treatment with the mitochondrial calcium influx blocker Ruthenium Red, but not with other cellular calcium flux blockers. Our data suggest a role for mitochondrial calcium influx in the mechanisms of mitochondrial and neuronal dysfunction in PD. Moreover, these studies support an important function for Pink1 in regulating mitochondrial activity under stress conditions.
Marongiu
Roberta
R
Department of Neurosciences, University of California, San Diego, La Jolla, California, USA.
Spencer
Brian
B
Crews
Leslie
L
Adame
Anthony
A
Patrick
Christina
C
Trejo
Margarita
M
Dallapiccola
Bruno
B
Valente
Enza Maria
EM
Masliah
Eliezer
E
D000255:Adenosine Triphosphate / Q000378:metabolism; D000409:Alanine / Q000235:genetics; D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D003035:Cobalt / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005439:Flufenamic Acid / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D009154:Mutation / Q000235:genetics*; D009447:Neuroblastoma / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D011494:Protein Kinases / Q000235:genetics*; D051381:Rats; D013912:Threonine / Q000235:genetics; D014162:Transfection; D014364:Tryptophan / Q000235:genetics; D051844:alpha-Synuclein / Q000235:genetics; D000099202:PTEN-Induced Putative Kinase
D000255:Adenosine Triphosphate; D000409:Alanine; D002118:Calcium; D003035:Cobalt; D005439:Flufenamic Acid; D049452:Green Fluorescent Proteins; D008869:Microtubule-Associated Proteins; D011494:Protein Kinases; D013912:Threonine; D014364:Tryptophan; D051844:alpha-Synuclein; D000099202:PTEN-Induced Putative Kinase; C477012:MAP1LC3A protein, human; C018021:cobaltous chloride