Szu-Chi Liao, Kohei Kano, Sadhna Phanse, Mai K. Nguyen, Elyssa B. Margolis, YuHong Fu, Jonathan X. Meng, Mohamed Taha Moutaoufik, Zac Chatterton, Tatiana D. Saccon, Kirsten Broderick, H Aoki, Jeffrey A. Simms, Felicia Suteja, Yoshitaka Sei, Eric J. Huang, Kevin McAvoy, Giovanni Manfredi, Glenda M. Halliday, Mohan Babu, Ken Nakamura
Mitochondrial dysfunction is a hallmark of Parkinson’s disease (PD), but the mechanisms by which it drives autosomal dominant and idiopathic forms of PD remain unclear. To investigate this, we generated and performed a comprehensive phenotypic analysis of a knock-in mouse model carrying the T61I mutation in the mitochondrial protein CHCHD2 (coiled-coil–helix–coiled-coil–helix domain–containing 2), which causes late-onset symptoms indistinguishable from idiopathic PD. We observed pronounced mitochondrial disruption in substantia nigra dopaminergic neurons, including distorted ultrastructure and CHCHD2 aggregation, as well as disrupted mitochondrial protein-protein interactions in brain lysates. These abnormalities were associated with a whole-body metabolic shift toward glycolysis, elevated mitochondrial reactive oxygen species (ROS), and progressive accumulation of aggregated α-synuclein. In idiopathic PD, CHCHD2 gene expression also correlated with α-synuclein levels in vulnerable dopaminergic neurons, and CHCHD2 protein accumulated in early Lewy aggregates. These findings delineate a pathogenic cascade in which CHCHD2 accumulation impairs mitochondrial respiration and increases ROS production, driving α-synuclein aggregation and neurodegeneration.