Mitochondrial Parkin Recruitment Is Impaired in Neurons Derived from Mutant PINK1 Induced Pluripotent Stem Cells

Abstract

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 mutations (c.509T>G; p.V170G) 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.

The pathways of mitophagy for quality control and clearance of mitochondria

“…These include application of valinomycin, a K þ ionophore, and antimycin A, a blocker of complex III, and these also induce recruitment of Parkin. 69,89 These compounds, although less drastic than CCCP, also affect the entire population of mitochondria. Damage to subsets of mitochondria has been achieved by photoirradiation 36 and by the inducing mitochondrial DNA damage.…”

A Dimeric PINK1-containing Complex on Depolarized Mitochondria Stimulates Parkin Recruitment

“…PINK1 simultaneously forms a high molecular weight complex with the translocase of the outer membrane (TOM) machinery (18). The ubiquitin ligase (E3) Parkin, another causal gene in autosomal recessive early onset parkinsonism (19,20), is subsequently recruited to the depolarized mitochondria and functions in the sequestration and/or elimination of damaged mitochondria in cultured cells (21), iPS-derived neurons (1,22,23), and mouse primary neurons (24 -26). PINK1 is essential for recruiting Parkin to the depolarized mitochondria; thus, it acts as an upstream factor of Parkin (15,16,(27)(28)(29)(30).…”

Induced pluripotent stem cells in rat models of Parkinson's disease: A systematic review and meta‑analysis

“…Lesions in the nigrostriatal DA neurons of rats are generated with 6-OHDA, which must be injected into the medial forebrain bundle, substantianigra pars compacta or striatum, rather than systemic administration, to produce the PD model, as it cannot cross the blood-brain barrier (34). The pathological and behavioral phenotypes of this model may differ from the human condition due to differences between species, therefore it is difficult to extrapolate the results obtained from animal models to humans (35). However, the results contribute to understanding the underlying genetic forms of PD and facilitate with establishing disease modifiers and novel targets for possible therapeutic intervention (36).…”