ACCUMULATION OF PARIS IN A DOPAMINERGIC CELL LINE MODEL LEADS TO PROGRESSIVE IMPAIRMENT OF MITOCHONDRIAL FUNCTION
Laura Scott1, Daniel Stevens2, Yunjong Lee2, Valina Dawson2, Ted Dawson.
1Campbell University, Buies Creek, NC, 2Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD.
Parkinson’s disease (PD) is a common neurodegenerative disease characterized by progressive motor impairment caused by the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). Significant evidence points to mitochondrial impairment as a key pathogenic event in PD. Parkin interacting substrate (PARIS) is a transcriptional repressor of PGC-1a that is accumulated in post-mortem PD brain samples and is a key mediator of dopaminergic cell death in models of parkin-linked PD. The impact of PARIS on mitochondrial function has not been described. Here we generated a PC-12 dopaminergic cell line model harboring a tet-promoter-driven PARIS transgene in order to investigate the impact of PARIS accumulation on mitochondrial function using microplate-based respirometry. Induction of the transgene by doxycycline removal induces robust PARIS overexpression and suppression of PGC-1a levels. PC-12 cells overexpressing PARIS exhibit a 37.27 (+/- 6)% reduction in maximal (CCCP-induced) mitochondrial respiration and a 64.8 (+/- 3.2)% reduction in respiratory reserve capacity with no significant differences in basal respiration or proton leaks. Continued induction of PARIS leads to progressive basal respiration deficits and a reduction in mitochondrial protein markers. Our findings suggest that PARIS accumulation leads to progressive reductions in mitochondrial health which may underlie dopaminergic cell death in PD.