nigrostriatal degeneration
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2022 ◽  
pp. 105612
Author(s):  
Alexia Polissidis ◽  
Effrosyni Koronaiou ◽  
Georgia Nikolopoulou ◽  
Catherine Viel ◽  
Maria Nikatou ◽  
...  

2021 ◽  
Vol 15 ◽  
Author(s):  
Eduard Bentea ◽  
Laura De Pauw ◽  
Lise Verbruggen ◽  
Lila C. Winfrey ◽  
Lauren Deneyer ◽  
...  

The astrocytic cystine/glutamate antiporter system xc– (with xCT as the specific subunit) imports cystine in exchange for glutamate and has been shown to interact with multiple pathways in the brain that are dysregulated in age-related neurological disorders, including glutamate homeostasis, redox balance, and neuroinflammation. In the current study, we investigated the effect of genetic xCT deletion on lactacystin (LAC)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of the nigrostriatal pathway, as models for Parkinson’s disease (PD). Dopaminergic neurons of adult xCT knock-out mice (xCT–/–) demonstrated an equal susceptibility to intranigral injection of the proteasome inhibitor LAC, as their wild-type (xCT+/+) littermates. Contrary to adult mice, aged xCT–/– mice showed a significant decrease in LAC-induced degeneration of nigral dopaminergic neurons, depletion of striatal dopamine (DA) and neuroinflammatory reaction, compared to age-matched xCT+/+ littermates. Given this age-related protection, we further investigated the sensitivity of aged xCT–/– mice to chronic and progressive MPTP treatment. However, in accordance with our previous observations in adult mice (Bentea et al., 2015a), xCT deletion did not confer protection against MPTP-induced nigrostriatal degeneration in aged mice. We observed an increased loss of nigral dopaminergic neurons, but equal striatal DA denervation, in MPTP-treated aged xCT–/– mice when compared to age-matched xCT+/+ littermates. To conclude, we reveal age-related protection against proteasome inhibition-induced nigrostriatal degeneration in xCT–/– mice, while xCT deletion failed to protect nigral dopaminergic neurons of aged mice against MPTP-induced toxicity. Our findings thereby provide new insights into the role of system xc– in mechanisms of dopaminergic cell loss and its interaction with aging.


Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1685
Author(s):  
Rachel Kelly ◽  
Andrew G. Cairns ◽  
Jörgen Ådén ◽  
Fredrik Almqvist ◽  
Alexis-Pierre Bemelmans ◽  
...  

Animal models of Parkinson’s disease, in which the human α-synuclein transgene is overexpressed in the nigrostriatal pathway using viral vectors, are widely considered to be the most relevant models of the human condition. However, although highly valid, these models have major limitations related to reliability and variability, with many animals exhibiting pronounced α-synuclein expression failing to demonstrate nigrostriatal neurodegeneration or motor dysfunction. Therefore, the aim of this study was to determine if sequential intra-nigral administration of AAV-α-synuclein followed by the small α-synuclein aggregating molecule, FN075, would enhance or precipitate the associated α-synucleinopathy, nigrostriatal pathology and motor dysfunction in subclinical models. Rats were given unilateral intra-nigral injections of AAV-α-synuclein (either wild-type or A53T mutant) followed four weeks later by a unilateral intra-nigral injection of FN075, after which they underwent behavioral testing for lateralized motor functionality until they were sacrificed for immunohistological assessment at 20 weeks after AAV administration. In line with expectations, both of the AAV vectors induced widespread overexpression of human α-synuclein in the substantia nigra and striatum. Sequential administration of FN075 significantly enhanced the α-synuclein pathology with increased density and accumulation of the pathological form of the protein phosphorylated at serine 129 (pS129-α-synuclein). However, despite this enhanced α-synuclein pathology, FN075 did not precipitate nigrostriatal degeneration or motor dysfunction in these subclinical AAV models. In conclusion, FN075 holds significant promise as an approach to enhancing the α-synuclein pathology in viral overexpression models, but further studies are required to determine if alternative administration regimes for this molecule could improve the reliability and variability in these models.


2021 ◽  
Author(s):  
Yi-Qing Lv ◽  
Lin Yuan ◽  
Yan Sun ◽  
Hao-Wen Dou ◽  
Ji-Hui Su ◽  
...  

Abstract Background: Growing evidence suggest the association between Parkinson’s disease (PD) and diabetes mellitus (DM). On a cellular level, it was proven that long-term elevated levels of glucose might lead to nigrostriatal degeneration in PD models. However, the underlying mechanism is still unclear. Previously, we have elucidated the potential of type 2 diabetes mellitus (T2DM) in facilitating PD progression, involving aggregation of both alpha-synuclein (α-syn) and islet amyloid polypeptide (IAPP) in the pancreatic and brain tissues. However, due to the complicated effect of insulin resistance on PD onset, the actual mechanism of hyperglycemia-induced dopaminergic degeneration remains unknown. Methods: In the present study, we employed the type 1 diabetes mellitus (T1DM) model induced by streptozotocin (STZ) injection, to investigate the direct effect of elevated blood glucose level on nigrostriatal degeneration. Results: We found that STZ treatment induced more severe pathological alterations in the pancreatic islets and T1DM symptoms in α-syn-overexpression mice than that in wild type (WT) mice, one month and three months after STZ injections. Behavioral tests evaluating motor performance confirmed the nigrostriatal degeneration. Furthermore, we observed a marked decrease in dopaminergic profiles and an increase of α-syn accumulation and Serine 129 (S129) phosphorylation in STZ-treated α-syn mice compared with vehicle-treated mice. At last, we observed more severe neuroinflammation in the brain of the STZ-treated α-syn mice.Conclusion: Our results solidify the potential link between DM and PD, providing insights on how hyperglycemia induces nigrostriatal degeneration and contributes to pathogenetic mechanisms in PD.


2021 ◽  
pp. 1-13
Author(s):  
Nicole K. Polinski

The use of wildtype recombinant alpha-synuclein preformed fibrils (aSyn PFFs) to induce endogenous alpha-synuclein to form pathological phosphorylation and trigger neurodegeneration is a popular model for studying Parkinson’s disease (PD) biology and testing therapeutic strategies. The strengths of this model lie in its ability torecapitulatethe phosphorylation/aggregationof aSyn and nigrostriatal degeneration seen in PD, as well as its suitability for studying the progressive nature of PD and the spread of aSyn pathology. Although the model is commonly used and has been adopted by many labs, variability in observed phenotypes exists. Here we provide summaries of the study design and reported phenotypes frompublished reports characterizing the aSyn PFF in vivo model in rodents following injection into the brain, gut, muscle, vein, peritoneum, and eye. These summariesare designed to facilitate an introduction to the use of aSyn PFFs to generate a rodent model of PD—highlighting phenotypes observed in papers that set out to thoroughly characterize the model.This information will hopefully improve the understanding of this model and clarify when the aSyn PFF model may be an appropriate choice for one’s research.


2021 ◽  
pp. 1-11
Author(s):  
Karoline Knudsen ◽  
Tatyana D. Fedorova ◽  
Jacob Horsager ◽  
Katrine B. Andersen ◽  
Casper Skjærbæk ◽  
...  

Background: We have hypothesized that Parkinson’s disease (PD) comprises two subtypes. Brain-first, where pathogenic α-synuclein initially forms unilaterally in one hemisphere leading to asymmetric nigrostriatal degeneration, and body-first with initial enteric pathology, which spreads through overlapping vagal innervation leading to more symmetric brainstem involvement and hence more symmetric nigrostriatal degeneration. Isolated REM sleep behaviour disorder has been identified as a strong marker of the body-first type. Objective: To analyse striatal asymmetry in [18F]FDOPA PET and [123I]FP-CIT DaT SPECT data from iRBD patients, de novo PD patients with RBD (PD +RBD) and de novo PD patients without RBD (PD - RBD). These groups were defined as prodromal body-first, de novo body-first, and de novo brain-first, respectively. Methods: We included [18F]FDOPA PET scans from 21 iRBD patients, 11 de novo PD +RBD, 22 de novo PD - RBD, and 18 controls subjects. Also, [123I]FP-CIT DaT SPECT data from iRBD and de novo PD patients with unknown RBD status from the PPPMI dataset was analysed. Lowest putamen specific binding ratio and putamen asymmetry index (AI) was defined. Results: Nigrostriatal degeneration was significantly more symmetric in patients with RBD versus patients without RBD or with unknown RBD status in both FDOPA (p = 0.001) and DaT SPECT (p = 0.001) datasets. Conclusion: iRBD subjects and de novo PD +RBD patients present with significantly more symmetric nigrostriatal dopaminergic degeneration compared to de novo PD - RBD patients. The results support the hypothesis that body-first PD is characterized by more symmetric distribution most likely due to more symmetric propagation of pathogenic α-synuclein compared to brain-first PD.


2021 ◽  
Vol 84 (2) ◽  
pp. 110-118
Author(s):  
Makoto Kobayashi ◽  
Satoshi Kuwabara

<b><i>Background:</i></b> In individuals with Parkinson’s disease (PD), visually guided saccades (VGSs) reportedly reflect general motor dysfunction and cognitive impairments. However, it has not been fully elucidated whether the VGS abnormalities result from nigrostriatal degeneration or other PD-related neural changes. <b><i>Methods:</i></b> We measured VGS latency and gain in 50 PD participants and 56 age-matched normal controls (NCs), and PD participants underwent dopamine transporter (DAT) single-photon emission computed tomography (SPECT) within 2 months of the measurement. VGSs were evoked by a white dot on a monitor, which was presented at the center and pseudo-randomly jumped off horizontally (10° or 20° eccentricity) or vertically (10° or 15°). First, we compared the parameters between PD participants and NCs for each target location. Second, in the participants who exhibited striatal DAT asymmetry on SPECT, VGSs contralaterally directed to the more severely affected striatum were compared with those ipsilaterally directed. Third, effects of the DAT-SPECT specific binding ratio (SBR) on VGSs were analyzed. <b><i>Results:</i></b> PD participants demonstrated prolonged latencies when the target was presented at the upward 15° eccentricity and decreased gains at all target locations. Contralateral VGSs relative to the side of the more severely affected striatum were more delayed and hypometric than ipsilateral. The SBR had a significant positive effect on VGS gain. <b><i>Conclusions:</i></b> In participants with PD, saccadic abnormalities were emphasized when VGSs were directed contralaterally to the more severely affected striatum. Moreover, the dopaminergic nigrostriatal degeneration on DAT-SPECT was mainly associated with VGS gain.


2021 ◽  
Author(s):  
Aurelie de Rus Jacquet ◽  
Abeje Ambaw ◽  
Mitali A Tambe ◽  
Sin Ying Ma ◽  
Michael A Timmers ◽  
...  

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently...


2020 ◽  
Vol 78 (4) ◽  
pp. 1721-1729
Author(s):  
Lars Frings ◽  
Bernhard Heimbach ◽  
Philipp T. Meyer ◽  
Sabine Hellwig

Background: Variations in alertness and attention are common in Lewy body diseases (LBD) and among the core features of dementia with Lewy bodies (DLB). Dopamine transporter SPECT is an accurate biomarker of nigrostriatal degeneration (NSD) in LBD. Objective: The present study investigated performance on a computerized alertness test as a potential measure of attention in patients with NSD compared to patients without NSD. Methods: Thirty-six patients with cognitive impairment plus at least one core feature of DLB referred for [123I]FP-CIT SPECT imaging were prospectively recruited. Performance in a computerized test of intrinsic alertness was compared between patients with and those without NSD as assessed by [123I]FP-CIT SPECT. Results: Reaction times to auditory stimuli (adjusted for age, sex, and education) were significantly longer in patients with NSD compared to those with a normal [123I]FP-CIT SPECT scan (p < 0.05). Statistical analyses revealed no significant differences comparing reaction times to visual stimuli or dispersion of reaction times between groups. Exploratory analysis in a subgroup of patients with available [18F]FDG PET revealed that longer reaction times were associated with decreased glucose metabolism in the prefrontal cortex (statistical parametric mapping, adjusted for age and sex; p < 0.005, cluster extent > 50 voxels). Conclusion: Computerized assessment of auditory reaction times is able to detect alertness deficits in patients with NSD and might help to measure alertness deficits in patients with LBD and NSD. Future studies in larger samples are needed to evaluate the diagnostic utility of computerized alertness assessment for the differential diagnosis of LBD.


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