Mitochondria-targeted oligomeric α-synuclein induces TOM40 degradation and mitochondrial dysfunction in Parkinson's disease and parkinsonism-dementia of Guam.
Velmarini Vasquez, Manohar Kodavati, Joy Mitra, Indira Vedula, Dale J Hamilton, Ralph M Garruto, K S Rao, Muralidhar L Hegde
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引用次数: 0
Abstract
Mitochondrial dysfunction is a central aspect of Parkinson's disease (PD) pathology, yet the underlying mechanisms are not fully understood. This study investigates the link between α-Synuclein (α-Syn) pathology and the loss of translocase of the outer mitochondrial membrane 40 (TOM40), unraveling its implications for mitochondrial dysfunctions in neurons. We discovered that TOM40 protein depletion occurs in the brains of patients with Guam Parkinsonism-Dementia (Guam PD) and cultured neurons expressing α-Syn proteinopathy, notably, without corresponding changes in TOM40 mRNA levels. Cultured neurons expressing α-Syn mutants, with or without a mitochondria-targeting signal (MTS) underscores the role of α-Syn's mitochondrial localization in inducing TOM40 degradation. PDe-related etiological factors, such as 6-hydroxydopamine or ROS/metal ions stress, which promotes α-Syn oligomerization, exacerbate TOM40 depletion in PD patient-derived cells with SNCA gene triplication. Although α-Syn interacts with both TOM40 and TOM20 in the outer mitochondrial membrane, degradation is selective for TOM40, which occurs via the ubiquitin-proteasome system (UPS) pathway. Our comprehensive analyses using Seahorse technology, mitochondrial DNA sequencing, and damage assessments, demonstrate that mutant α-Syn-induced TOM40 loss results in mitochondrial dysfunction, characterized by reduced membrane potential, accumulation of mtDNA damage, deletion/insertion mutations, and altered oxygen consumption rates. Notably, ectopic supplementation of TOM40 or reducing pathological forms of α-Syn using ADP-ribosylation inhibitors ameliorate these mitochondrial defects, suggesting potential therapeutic avenues. In conclusion, our findings provide crucial mechanistic insights into how α-Syn accumulation leads to TOM40 degradation and mitochondrial dysfunction, offering insights for targeted interventions to alleviate mitochondrial defects in PD.
期刊介绍:
Brought to readers by the editorial team of Cell Death & Differentiation, Cell Death & Disease is an online peer-reviewed journal specializing in translational cell death research. It covers a wide range of topics in experimental and internal medicine, including cancer, immunity, neuroscience, and now cancer metabolism.
Cell Death & Disease seeks to encompass the breadth of translational implications of cell death, and topics of particular concentration will include, but are not limited to, the following:
Experimental medicine
Cancer
Immunity
Internal medicine
Neuroscience
Cancer metabolism