Mitochondrial parkin recruitment is impaired in neurons derived from mutant PINK1 induced pluripotent stem cells

Genetic Parkinson disease (PD) has been associated with mutations in PINK1, a gene encoding a mitochondrial kinase implicated in the regulation of mitochondrial degradation. While the studies so far examined PINK1 function in non-neuronal systems or through PINK1 knockdown approaches, there is an imperative to examine the role of endogenous PINK1 in appropriate human-derived and biologically relevant cell models. Here we report the generation of induced pluripotent stem (iPS) cells from skin fibroblasts taken from three PD patients with nonsense (c.1366C>T; p.Q456X) or missense (c.509T>G; p.V170G) mutations in the PINK1 gene. These cells were differentiated into dopaminergic neurons that upon mitochondrial depolarization showed impaired recruitment of lentivirally expressed Parkin to mitochondria, increased mitochondrial copy number, and upregulation of PGC-1α, an important regulator of mitochondrial biogenesis. Importantly, these alterations were corrected by lentiviral expression of wild-type PINK1 in mutant iPS cell-derived PINK1 neurons. In conclusion, our studies suggest that fibroblasts from genetic PD can be reprogrammed and differentiated into neurons. These neurons exhibit distinct phenotypes that should be amenable to further mechanistic studies in this relevant biological context.