Altered Mitochondrial Bioenergetics and Calcium Kinetics in Young-Onset PLA2G6 Parkinson's Disease iPSCs

Parkinson's disease (PD) has emerged as a multisystem disorder affecting multiple cellular and organellar systems in addition to the dopaminergic neurons. Disease-specific induced pluripotent stem cells (iPSCs) model early developmental changes and cellular perturbations that are otherwise inaccessible from clinical settings. Here, we report the early changes in patient-derived iPSCs carrying a homozygous recessive mutation, R741Q, in the PLA2G6 gene. A gene-edited R747W iPSC line mirrored these phenotypes, thus validating our initial findings. Bioenergetic dysfunction and hyperpolarization of mitochondrial membrane potentials were hallmarks of the PD iPSCs. Further, a concomitant increase in glycolytic activity indicated a possible compensation for mitochondrial respiration. Elevated basal reactive oxygen species (ROS) and decreased catalase expression were also observed in the disease iPSCs. No change in autophagy was detected. These inceptive changes could be potential targets for early intervention of prodromal PD in the absence of disease-modifying therapies. However, additional investigations are crucial to delineate the cause-effect relationships of these observations.