Calcium Homeostatasis and Mitochondrial Dysfunction in Dopaminergic Neurons of the Substantia Nigra

2010 ◽  
Author(s):  
D. J. Surmeier
Keyword(s):  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons

scholarly journals Protection from α-Synuclein induced dopaminergic neurodegeneration by overexpression of the mitochondrial import receptor TOM20

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Briana R. De Miranda ◽  
Emily M. Rocha ◽  
Sandra L. Castro ◽  
J. Timothy Greenamyre
Keyword(s):  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Expression System ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Import ◽  
In Vivo Models ◽  
Dopaminergic Neurodegeneration ◽  
Import Receptor

AbstractDopaminergic neurons of the substantia nigra are selectively vulnerable to mitochondrial dysfunction, which is hypothesized to be an early and fundamental pathogenic mechanism in Parkinson’s disease (PD). Mitochondrial function depends on the successful import of nuclear-encoded proteins, many of which are transported through the TOM20–TOM22 outer mitochondrial membrane import receptor machinery. Recent data suggests that post-translational modifications of α-synuclein promote its interaction with TOM20 at the outer mitochondrial membrane and thereby inhibit normal protein import, leading to dysfunction, and death of dopaminergic neurons. As such, preservation of mitochondrial import in the face of α-synuclein accumulation might be a strategy to prevent dopaminergic neurodegeneration, however, this is difficult to assess using current in vivo models of PD. To this end, we established an exogenous co-expression system, utilizing AAV2 vectors to overexpress human α-synuclein and TOM20, individually or together, in the adult Lewis rat substantia nigra to assess whether TOM20 overexpression attenuates α-synuclein-induced dopaminergic neurodegeneration. Twelve weeks after viral injection, we observed that AAV2-TOM20 expression was sufficient to prevent loss of nigral dopaminergic neurons caused by AAV2-αSyn overexpression. The observed TOM20-mediated dopaminergic neuron preservation appeared to be due, in part, to the rescued expression (and presumed import) of nuclear-encoded mitochondrial electron transport chain proteins that were inhibited by α-synuclein overexpression. In addition, TOM20 overexpression rescued the expression of the chaperone protein GRP75/mtHSP70/mortalin, a stress-response protein involved in α-synuclein-induced injury. Collectively, these data indicate that TOM20 expression prevents α-synuclein-induced mitochondrial dysfunction, which is sufficient to rescue dopaminergic neurons in the adult rat brain.

scholarly journals Protection from α-synuclein-induced dopaminergic neurodegeneration by overexpression of the mitochondrial import receptor TOM20 in the rat midbrain

2020 ◽  
Author(s):  
Briana R. De Miranda ◽  
Emily M. Rocha ◽  
Sandra Castro ◽  
J. Timothy Greenamyre
Keyword(s):  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Protein Import ◽  
Expression System ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Import ◽  
Dopaminergic Neurodegeneration ◽  
Import Receptor

Dopaminergic neurons of the substantia nigra are selectively vulnerable to mitochondrial dysfunction, which is hypothesized to be an early and fundamental pathogenic mechanism in Parkinson’s disease (PD). Mitochondrial function depends on the successful import of nuclear-encoded proteins, many of which are transported through the TOM20-TOM22 outer mitochondrial membrane import receptor machinery. Recent data suggests that post-translational modifications of α-synuclein promote its interaction with TOM20 at the outer mitochondrial membrane and thereby inhibit normal protein import, which leads to dysfunction and death of dopaminergic neurons. As such, preservation of mitochondrial import in the face of α-synuclein accumulation might be a strategy to prevent dopaminergic neurodegeneration, however, this is difficult to assess using current in vivo models of PD. To this end, we established an exogenous co-expression system, utilizing AAV2 vectors to overexpress human α-synuclein and TOM20, individually or together, in the adult Lewis rat substantia nigra in order to assess whether TOM20 overexpression attenuates α-synuclein-induced dopaminergic neurodegeneration. Twelve weeks after viral injection, we observed that AAV2-TOM20 expression was sufficient to prevent loss of nigral dopaminergic neurons caused by AAV2-αSyn overexpression. The observed TOM20-mediated dopaminergic neuron preservation appeared to be due, in part, to the rescued import of nuclear-encoded mitochondrial electron transport chain proteins that were inhibited by α-synuclein overexpression. In addition, TOM20 overexpression rescued the import of the chaperone protein GRP75/mtHSP70/mortalin, a stress-response protein involved in α-synuclein-induced injury. Collectively, these data indicate that TOM20 expression prevents α-synuclein-induced mitochondrial dysfunction, which is sufficient to rescue dopaminergic neurons in the adult rat brain.

Neuroinflammation caused by activated microglia and astrocytes can contribute to the progression of pathogenic damage to substantia nigra neurons, playing a role in Parkinson's disease progression

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Oxidative Stress ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Molecular Mechanisms ◽  
High Energy ◽  
Molecular Pathways ◽  
Activated Microglia

Parkinson's disease progresses by a number of regionally specific cellular and molecular mechanisms. Furthermore, these pathways interact and have an influence on one another in both normal and pathological conditions. Neuroinflammation caused by activated microglia and astrocytes can contribute to the progression of pathogenic damage to substantia nigra (SN) neurons. Similarly, oxidative stress may be caused by a variety of stressors, such as contaminants in the environment or age-related mitochondrial dysfunction, leading to the production of reactive oxygen species (ROS). Dopamine auto-oxidation is a significant generator of ROS in dopaminergic neurons, resulting in neuronal oxidative stress. The high energy demands of dopaminergic neurons may result in mitochondrial dysfunction and oxidative damage as they age. Because mitophagy clears dysfunctional mitochondria from SN neurons, mutation-related abnormalities in autophagy of defective proteins might allow damaging proteins to accumulate in the cell. Because the effects of aging on these molecular pathways and cellular activities are unknown, further study into these molecular pathways and their connections in normal and sick states will be essential for developing disease-specific therapies.

scholarly journals Imaging mass cytometry reveals generalised deficiency in OXPHOS complexes in Parkinson’s disease

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chun Chen ◽  
David McDonald ◽  
Alasdair Blain ◽  
Ashwin Sachdeva ◽  
Laura Bone ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Oxidative Phosphorylation ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Disease ◽  
Dopaminergic Neurons ◽  
Neuronal Response ◽  
Proteomic Profiling ◽  
Mass Cytometry ◽  
And Control

AbstractHere we report the application of a mass spectrometry-based technology, imaging mass cytometry, to perform in-depth proteomic profiling of mitochondrial complexes in single neurons, using metal-conjugated antibodies to label post-mortem human midbrain sections. Mitochondrial dysfunction, particularly deficiency in complex I has previously been associated with the degeneration of dopaminergic neurons in Parkinson’s disease. To further our understanding of the nature of this dysfunction, and to identify Parkinson’s disease specific changes, we validated a panel of antibodies targeting subunits of all five mitochondrial oxidative phosphorylation complexes in dopaminergic neurons from Parkinson’s disease, mitochondrial disease, and control cases. Detailed analysis of the expression profile of these proteins, highlighted heterogeneity between individuals. There is a widespread decrease in expression of all complexes in Parkinson’s neurons, although more severe in mitochondrial disease neurons, however, the combination of affected complexes varies between the two groups. We also provide evidence of a potential neuronal response to mitochondrial dysfunction through a compensatory increase in mitochondrial mass. This study highlights the use of imaging mass cytometry in the assessment and analysis of expression of oxidative phosphorylation proteins, revealing the complexity of deficiencies of these proteins within individual neurons which may contribute to and drive neurodegeneration in Parkinson’s disease.

The Effects of Fibrillar Forms of α-Synuclein Protein on Neurogenesis in the Hippocampus, Dopaminergic Neurons of the Substantia Nigra, and the Behavior of Ageing Mice

2018 ◽  
Vol 12 (4) ◽  
pp. 359-365
Author(s):  
V. V. Sherstnev ◽  
O. A. Solov’eva ◽  
M. A. Gruden’ ◽  
A. V. Kedrov ◽  
E. V. Konovalova ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Dopaminergic Neurons

scholarly journals Neuroprotective Effect of Nortriptyline in Overt Hepatic Encephalopathy Through Attenuation of Mitochondrial Dysfunction

ASN NEURO ◽  
2018 ◽  
Vol 10 ◽  
pp. 175909141881058 ◽  
Author(s):  
Ji Heun Jeong ◽  
Do Kyung Kim ◽  
Nam-Seob Lee ◽  
Young-Gil Jeong ◽  
Ho Won Kim ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatic Encephalopathy ◽  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Permeability Transition ◽  
Neuroprotective Effect ◽  
Motor Deficits ◽  
Apoptotic Pathway ◽  
Duct Ligation ◽  
Overt Hepatic Encephalopathy

Hyperammonemia associated with overt hepatic encephalopathy (OHE) causes excitotoxic neuronal death through activation of the cytochrome C (CytC)-mediated mitochondria-dependent apoptotic pathway. We tested the therapeutic effect of nortriptyline (NT), a mitochondrial permeability transition pore (mPTP) blocker that can possibly inhibit mitochondrial CytC efflux to the cytosol on in vivo and in vitro OHE models. After ensuring the generation of OHE rats, established by bile duct ligation (BDL), they were intraperitoneally administered either 20 mg/kg NT (i.e., BDL+NT) or another vehicle (i.e., BDL+VEH) for 14 days. Compared with the control, BDL+VEH showed an increment of motor deficits, cell death, synaptic loss, apoptosis, and mitochondria with aberrant morphology in substantia nigra compacta dopaminergic (DA-ergic) neurons. However, the extent was significantly reversed in BDL+NT. Subsequently, we studied the neuroprotective mechanism of NT using PC-12 cells, a DA-ergic cell line, which exposed glutamate used as an excitotoxin. Compared with the control, the cells exposed to 15 mM glutamate (i.e., GLU) showed incremental cell death, apoptosis, and demise in mitochondrial respiration. Importantly, efflux of CytC from mitochondria to cytosol and the dissipation of mitochondrial membrane potential (△Ψm), an indicator of mPTP opening, were prominent in GLU. However, compared with the GLU, the cells cotreated with 10 μM NT (i.e., GLU+NT) showed a significant reduction in the aforementioned phenomenon. Together, we concluded that NT can be used for OHE therapeutics, mitigating the excitotoxic death of substantia nigra compacta DA-ergic neurons via mPTP-associated mitochondrial dysfunction inhibition.

Cardiovascular depressor responses to stimulation of substantia nigra and ventral tegmental area

1997 ◽  
Vol 273 (6) ◽  
pp. H2549-H2557 ◽  
Author(s):  
Gilbert J. Kirouac ◽  
John Ciriello
Keyword(s):  
Substantia Nigra ◽  
Ventral Tegmental Area ◽  
Intravenous Administration ◽  
Dopaminergic Neurons ◽  
Cardiovascular Responses ◽  
Receptor Blocker ◽  
Transitional Region ◽  
Pars Lateralis ◽  
Ventral Tegmental ◽  
Stimulation Of

Experiments were done in α-chloralose-anesthetized, paralyzed, and artificially ventilated rats to investigate the effect ofl-glutamate (Glu) stimulation of the substantia nigra (SN) and ventral tegmental area (VTA) on arterial pressure (AP) and heart rate (HR). Glu stimulation of the SN pars compacta (SNC) elicited decreases in both mean AP (MAP; −18.9 ± 1.3 mmHg; n = 52) and HR (−26.1 ± 1.6 beats/min; n = 46) at 81% of the sites stimulated. On the other hand, stimulation of the SN pars lateralis or pars reticulata did not elicit cardiovascular responses. Stimulation of the adjacent VTA region elicited similar decreases in MAP (−18.0 ± 2.6 mmHg; n = 20) and HR (−25.4 ± 3.8 beats/min; n = 17) at ∼74% of the sites stimulated. Intravenous administration of the dopamine D2-receptor antagonist raclopride significantly attenuated both the MAP (70%) and the HR (54%) responses elicited by stimulation of the transitional region where the SNC merges with the lateral VTA (SNC-VTA region). Intravenous administration of the muscarinic receptor blocker atropine methyl bromide had no effect on the magnitude of the MAP and HR responses to stimulation of the SNC-VTA region, whereas administration of the nicotinic receptor blocker hexamethonium bromide significantly attenuated both the depressor and the bradycardic responses. These data suggest that dopaminergic neurons in the SNC-VTA region activate a central pathway that exerts cardiovascular depressor effects that are mediated by the inhibition of sympathetic vasoconstrictor fibers to the vasculature and cardioacceleratory fibers to the heart.

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