High-Resolution Respirometry Reveals MPP + Mitochondrial Toxicity Mechanism in a Cellular Model of Parkinson's Disease

• Published in: International journal of molecular sciences 2020-10, Vol.21 (21), p.7809
• Main Authors: Risiglione, Pierpaolo, Leggio, Loredana, Cubisino, Salvatore A M, Reina, Simona, Paternò, Greta, Marchetti, Bianca, Magrì, Andrea, Iraci, Nunzio, Messina, Angela
• Format: Article
• Language: English
• Subjects: 1-Methyl-4-phenylpyridinium - toxicity; Adenosine Diphosphate - metabolism; Apoptosis; Cell culture; Cell Death - drug effects; Cell differentiation; Cell Differentiation - drug effects; Cell Line, Tumor; Cell lines; Degeneration; Depletion; Dopamine; Dopamine receptors; Electron transport; Electron transport chain; Electron Transport Complex III - metabolism; Genotype & phenotype; Herbicides; High resolution; Humans; Metabolites; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondria - pathology; Mitochondrial Membranes - drug effects; Mitochondrial Membranes - pathology; MPP; MPTP; Neuroblastoma; Neuroblasts; Neurodegeneration; Neurons - drug effects; Neurons - metabolism; Neurons - pathology; Neurotoxicity; Oxidative Phosphorylation - drug effects; Oxygen - metabolism; Oxygen consumption; Paraquat; Parkinson Disease - pathology; Parkinson's disease; Phosphorylation; Protocol; Respiration; Respirometry; Standardization; Toxicity; Toxins
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21217809

MPP is the active metabolite of MPTP, a molecule structurally similar to the herbicide Paraquat, known to injure the dopaminergic neurons of the nigrostriatal system in Parkinson's disease models. Within the cells, MPP accumulates in mitochondria where it inhibits complex I of the electron transport chain, resulting in ATP depletion and neuronal impairment/death. So far, MPP is recognized as a valuable tool to mimic dopaminergic degeneration in various cell lines. However, despite a large number of studies, a detailed characterization of mitochondrial respiration in neuronal cells upon MPP treatment is still missing. By using high-resolution respirometry, we deeply investigated oxygen consumption related to each respiratory state in differentiated neuroblastoma cells exposed to the neurotoxin. Our results indicated the presence of extended mitochondrial damage at the inner membrane level, supported by increased LEAK respiration, and a drastic drop in oxygen flow devoted to ADP phosphorylation in respirometry measurements. Furthermore, prior to complex I inhibition, an enhancement of complex II activity was observed, suggesting the occurrence of some compensatory effect. Overall our findings provide a mechanistic insight on the mitochondrial toxicity mediated by MPP , relevant for the standardization of studies that employ this neurotoxin as a disease model.