Mitochondrial dysfunction in Parkinson's disease

1999 ◽  
Vol 66 ◽  
pp. 85-97 ◽  
Author(s):  
J.Timothy Greenamyre ◽  
Gillian MacKenzie ◽  
Tsung-I Peng ◽  
Stacy E. Stephans

The cause of Parkinson's disease (PD) is unknown, but reduced activity of complex I of the electron-transport chain has been implicated in the pathogenesis of both mitochondrial permeability transition pore-induced Parkinsonism and idiopathic PD. We developed a novel model of PD in which chronic, systemic infusion of rotenone, a complex-I inhibitor, selectively kills dopaminergic nerve terminals and causes retrograde degeneration of substantia nigra neurons over a period of months. The distribution of dopaminergic pathology replicates that seen in PD, and the slow time course of neurodegeneration mimics PD more accurately than current models. Our model should enhance our understanding of neurodegeneration in PD. Metabolic impairment depletes ATP, depresses Na+/K(+)-ATPase activity, and causes graded neuronal depolarization. This relieves the voltage-dependent Mg2+ block of the N-methyl-d-aspartate (NMDA) subtype of the glutamate receptor, which is highly permeable to Ca2+. Consequently, innocuous levels of glutamate become lethal via secondary excitotoxicity. Mitochondrial impairment also disrupts cellular Ca2+ homoeostasis. Moreover, the facilitation of NMDA-receptor function leads to further mitochondrial dysfunction. To a large part, this occurs because Ca2+ entering neurons through NMDA receptors has 'privileged' access to mitochondria, where it causes free-radical production and mitochondrial depolarization. Thus there may be a feed-forward cycle wherein mitochondrial dysfunction causes NMDA-receptor activation, which leads to further mitochondrial impairment. In this scenario, NMDA-receptor antagonists may be neuroprotective.

2020 ◽  
Vol 477 (6) ◽  
pp. 1109-1122 ◽  
Author(s):  
Upasana Ganguly ◽  
Anindita Banerjee ◽  
Sankha Shubhra Chakrabarti ◽  
Upinder Kaur ◽  
Oishimaya Sen ◽  
...  

The toxicity of accumulated α-synuclein plays a key role in the neurodegeneration of Parkinson's disease (PD). This study has demonstrated that iron in varying concentrations (up to 400 µM) causes an increase in α-synuclein content in SH-SY5Y cells associated with mitochondrial depolarization, decreased cellular ATP content and loss of cell viability during incubation up to 96 h. Knocking-down α-synuclein expression prevents cytotoxic actions of iron, which can also be prevented by cyclosporine A (a blocker of mitochondrial permeability transition pore). These results indicate that iron cytotoxicity is mediated by α-synuclein acting on mitochondria. Likewise siRNA mediated knock-down of Parkin causes an accumulation of α-synuclein accompanied by mitochondrial dysfunction and cell death during 48 h incubation under basal conditions, but these changes are not further aggravated by co-incubation with iron (400 µM). We have also analyzed mitochondrial dysfunction and cell viability in SH-SY5Y cells under double knock-down (α-synuclein and Parkin concurrently) conditions during incubation for 48 h with or without iron. Our results tend to suggest that iron inactivates Parkin in SH-SY5Y cells and thereby inhibits the proteasomal degradation of α-synuclein, and the accumulated α-synuclein causes mitochondrial dysfunction and cell death. These results have implications in the pathogenesis of sporadic PD and also familial type with Parkin mutations.


2020 ◽  
Vol 15 (3) ◽  
pp. FNL49
Author(s):  
Sankha S Chakrabarti ◽  
Venkatadri S Sunder ◽  
Upinder Kaur ◽  
Sapna Bala ◽  
Priyanka Sharma ◽  
...  

Aim: A large body of evidence has implicated the cytotoxicity of α-synuclein in Parkinson’s disease (PD). We planned to use a bioinformatics-based approach to gain further insight into this process. Materials & methods: Using STRING version 10, we identified interacting proteins of α-synuclein. Using α-synuclein and one of these interactors involved in apoptosis as query proteins, we identified other linked proteins. We further analyzed the interactions between some of these proteins by Protein–Protein Docking using ClusPro. Results: We identified BAX as an interacting protein of α-synuclein. Interactions of α-synuclein and BAX as well as BAX and BCL2L1 were determined. Conclusion: The interaction of α-synuclein and BAX could play a crucial role in the cell death process of PD where apoptosis and mitochondrial permeability transition-driven necrosis may coexist.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Andrew C. Kent ◽  
Khairat Bahgat Youssef El Baradie ◽  
Mark W. Hamrick

The aging process is associated with significant alterations in mitochondrial function. These changes in mitochondrial function are thought to involve increased production of reactive oxygen species (ROS), which over time contribute to cell death, senescence, tissue degeneration, and impaired tissue repair. The mitochondrial permeability transition pore (mPTP) is likely to play a critical role in these processes, as increased ROS activates mPTP opening, which further increases ROS production. Injury and inflammation are also thought to increase mPTP opening, and chronic, low-grade inflammation is a hallmark of aging. Nicotinamide adenine dinucleotide (NAD+) can suppress the frequency and duration of mPTP opening; however, NAD+ levels are known to decline with age, further stimulating mPTP opening and increasing ROS release. Research on neurodegenerative diseases, particularly on Parkinson’s disease (PD) and Alzheimer’s disease (AD), has uncovered significant findings regarding mPTP openings and aging. Parkinson’s disease is associated with a reduction in mitochondrial complex I activity and increased oxidative damage of DNA, both of which are linked to mPTP opening and subsequent ROS release. Similarly, AD is associated with increased mPTP openings, as evidenced by amyloid-beta (Aβ) interaction with the pore regulator cyclophilin D (CypD). Targeted therapies that can reduce the frequency and duration of mPTP opening may therefore have the potential to prevent age-related declines in cell and tissue function in various systems including the central nervous system.


2006 ◽  
Vol 291 (6) ◽  
pp. C1159-C1171 ◽  
Author(s):  
David D. Arrington ◽  
Terry R. Van Vleet ◽  
Rick G. Schnellmann

Calpains, Ca2+-activated cysteine proteases, are cytosolic enzymes implicated in numerous cellular functions and pathologies. We identified a mitochondrial Ca2+-inducible protease that hydrolyzed a calpain substrate (SLLVY-AMC) and was inhibited by active site-directed calpain inhibitors as calpain 10, an atypical calpain lacking domain IV. Immunoblot analysis and activity assays revealed calpain 10 in the mitochondrial outer membrane, intermembrane space, inner membrane, and matrix fractions. Mitochondrial staining was observed when COOH-terminal green fluorescent protein-tagged calpain 10 was overexpressed in NIH-3T3 cells and the mitochondrial targeting sequence was localized to the NH2-terminal 15 amino acids. Overexpression of mitochondrial calpain 10 resulted in mitochondrial swelling and autophagy that was blocked by the mitochondrial permeability transition (MPT) inhibitor cyclosporine A. With the use of isolated mitochondria, Ca2+-induced MPT was partially decreased by calpain inhibitors. More importantly, Ca2+-induced inhibition of Complex I of the electron transport chain was blocked by calpain inhibitors and two Complex I proteins were identified as targets of mitochondrial calpain 10, NDUFV2, and ND6. In conclusion, calpain 10 is the first reported mitochondrially targeted calpain and is a mediator of mitochondrial dysfunction through the cleavage of Complex I subunits and activation of MPT.


Biomolecules ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 119 ◽  
Author(s):  
Emily N. Cronin-Furman ◽  
Jennifer Barber-Singh ◽  
Kristen E. Bergquist ◽  
Takao Yagi ◽  
Patricia A. Trimmer

Parkinson’s disease (PD) is a neurodegenerative disorder that exhibits aberrant protein aggregation and mitochondrial dysfunction. Ndi1, the yeast mitochondrial NADH dehydrogenase (complex I) enzyme, is a single subunit, internal matrix-facing protein. Previous studies have shown that Ndi1 expression leads to improved mitochondrial function in models of complex I-mediated mitochondrial dysfunction. The trans-mitochondrial cybrid cell model of PD was created by fusing mitochondrial DNA-depleted SH-SY5Y cells with platelets from a sporadic PD patient. PD cybrid cells reproduce the mitochondrial dysfunction observed in a patient’s brain and periphery and form intracellular, cybrid Lewy bodies comparable to Lewy bodies in PD brain. To improve mitochondrial function and alter the formation of protein aggregates, Ndi1 was expressed in PD cybrid cells and parent SH-SY5Y cells. We observed a dramatic increase in mitochondrial respiration, increased mitochondrial gene expression, and increased PGC-1α gene expression in PD cybrid cells expressing Ndi1. Total cellular aggregated protein content was decreased but Ndi1 expression was insufficient to prevent cybrid Lewy body formation. Ndi1 expression leads to improved mitochondrial function and biogenesis signaling, both processes that could improve neuron survival during disease. However, other aspects of PD pathology such as cybrid Lewy body formation were not reduced. Consequently, resolution of mitochondrial dysfunction alone may not be sufficient to overcome other aspects of PD-related cellular pathology.


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