The role of endogenous PINK1 and Parkin mutations in human dopaminergic neurons

Parkinson disease (PD) is the second most common neurodegenerative disorder, characterized by the loss of dopaminergic neurons in the substantia nigra. A clinical syndrome resembling ‘idiopathic’ PD has been reported for recessively inherited Parkin- and PINK1-linked PD. Our overall hypothesis in this application is that impairment of mitochondrial function in vulnerable neurons plays a key role in the pathogenesis of PD and that restoration of mitochondrial function will result in neuroprotection. As the function of the encoded proteins has been mainly investigated in non-neuronal systems or through knockdown approaches, there is an imperative to examine the role of endogenous mutations in appropriate human-derived and biologically relevant cell models. The objective of this study is to generate and characterize pure populations of iPS cell-derived dopaminergic neurons by using a novel differentiation strategy. Parkin and PINK1 mutant neurons will be examined for toxicity and mitochondrial function and compared to controls. In order to more directly test whether the observed phenotypes are related to pathogenic mutations, we intend to examine rescue strategies. We will express PGC-1α, an important regulator of mitochondrial biogenesis, and employ genetic rescue using zinc finger technology that allows for selective repair of endogenous mutations.