Cerebral mitochondrial electron transport chain dysfunction in multiple system atrophy and Parkinson’s disease

Despite recent advancements in the biomedical fields, the etiology and pathogenesis of Parkinson’s disease (PD) is still poorly understood, though the crucial roles of oxidative stress and impaired mitochondrial respiration have been suggested in the development of PD. The oxidative modification of the proteins of mitochondrial electron transport chain alters their normal function leading to the state of energy crisis in neurons. Exposure of environmental chemicals such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone in mouse produces the symptoms akin to PD and therefore these neurotoxins are commonly used in experimental studies on PD. Another environmental toxin, paraquat (a commonly used herbicide) has also been implicated with the onset of PD. The neurotoxicity of these chemicals is accompanied by the blockade of electron flow from NADH dehydrogenase to coenzyme Q. The agents with the ability to improve mitochondrial respiration and ATP production have been shown to exert beneficial effects in PD patients as well as in the animal models of PD. This review summarizes the current research implicating the impairment of mitochondrial respiratory chain and the role of environmental toxins in the pathogenesis of PD.

Download Full-text

Mitochondrial Function and Parkinson’s Disease: From the Perspective of the Electron Transport Chain

Frontiers in Molecular Neuroscience ◽

10.3389/fnmol.2021.797833 ◽

2021 ◽

Vol 14 ◽

Author(s):

Jeng-Lin Li ◽

Tai-Yi Lin ◽

Po-Lin Chen ◽

Ting-Ni Guo ◽

Shu-Yi Huang ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Electron Transport ◽

Complex I ◽

Electron Transport Chain ◽

Direct Evidence ◽

Complex Iii ◽

Complex Iv ◽

Transport Chain ◽

Mitochondrial Functions

Parkinson’s disease (PD) is known as a mitochondrial disease. Some even regarded it specifically as a disorder of the complex I of the electron transport chain (ETC). The ETC is fundamental for mitochondrial energy production which is essential for neuronal health. In the past two decades, more than 20 PD-associated genes have been identified. Some are directly involved in mitochondrial functions, such as PRKN, PINK1, and DJ-1. While other PD-associate genes, such as LRRK2, SNCA, and GBA1, regulate lysosomal functions, lipid metabolism, or protein aggregation, some have been shown to indirectly affect the electron transport chain. The recent identification of CHCHD2 and UQCRC1 that are critical for functions of complex IV and complex III, respectively, provide direct evidence that PD is more than just a complex I disorder. Like UQCRC1 in preventing cytochrome c from release, functions of ETC proteins beyond oxidative phosphorylation might also contribute to the pathogenesis of PD.

Download Full-text

AB0031 T HELPER 17 CELLS WERE SIGNIFICANTLY DECREASED BY MITOCHONDRIAL ELECTRON TRANSPORT CHAIN COMPLEX INHIBITOR IN PATIENTS WITH RHEUMATOID ARTHRITIS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.3441 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1318.2-1318

Author(s):

H. R. Lee ◽

S. J. Yoo ◽

J. Kim ◽

I. S. Yoo ◽

C. K. Park ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Electron Transport ◽

Disease Activity ◽

Th17 Cells ◽

Electron Transport Chain ◽

Chain Complex ◽

Complex Iii ◽

Mitochondrial Electron Transport Chain ◽

Transport Chain ◽

Healthy Control

Background:Reactive oxygen species (ROS) and T helper 17 (TH17) cells have been known to play an important role in the pathogenesis of rheumatoid arthritis (RA). However, the interrelationship between ROS and TH17 remains unclear in RAObjectives:To explore whether ROS affect TH17 cells in peripheral blood mononuclear cells (PBMC) of RA patients, we analyzed ROS expressions among T cell subsets following treatment with mitochondrial electron transport chain complex inhibitors.Methods:Blood samples were collected from 40 RA patients and 10 healthy adult volunteers. RA activity was divided according to clinical parameter DAS28. PBMC cells were obtained from the whole blood using lymphocyte separation medium density gradient centrifugation. Following PBMC was stained with Live/Dead stain dye, cells were incubated with antibodies for CD3, CD4, CD8, and CD25. After fixation and permeabilization, samples were stained with antibodies for FoxP3 and IL-17A. MitoSox were used for mitochondrial specific staining.Results:The frequency of TH17 cells was increased by 4.83 folds in moderate disease activity group (5.1>DAS28≥3.2) of RA patients compared to healthy control. Moderate RA activity patients also showed higher ratio of TH17/Treg than healthy control (3.57 folds). All RA patients had elevated expression of mitochondrial specific ROS than healthy control. When PBMC cells were treated with 2.5uM of antimycin A (mitochondrial electron transport chain complex III inhibitor) for 16 h, the frequency of TH17 cells was significantly decreased.Conclusion:The mitochondrial electron transport chain complex III inhibitor markedly downregulated the frequency of TH17 cells in moderate disease activity patients with RA. These findings provide a novel approach to regulate TH17 function in RA through mitochondrial metabolism related ROS production.References:[1]Szekanecz, Z., et al., New insights in synovial angiogenesis. Joint Bone Spine, 2010. 77(1): p. 13-9.[2]Prevoo, M.L., et al., Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum, 1995. 38(1): p. 44-8.Disclosure of Interests:None declared

Download Full-text