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Neuroscience Jul 2023Levodopa-induced dyskinesia (LID) is a common motor complication of levodopa (L-DOPA) treatment for Parkinson's disease (PD). In recent years, the role of astrocytes in...
BACKGROUND
Levodopa-induced dyskinesia (LID) is a common motor complication of levodopa (L-DOPA) treatment for Parkinson's disease (PD). In recent years, the role of astrocytes in LID has increasingly attracted attention.
OBJECTIVE
To explore the effect of an astrocyte regulator (ONO-2506) on LID in a rat model and the potential underlying physiological mechanism.
METHODS
Unilateral LID rat models, established by administering 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle through stereotactic injection, were injected with ONO-2506 or saline into the striatum through brain catheterization and were administered L-DOPA to induce LID. Through a series of behavioral experiments, LID performance was observed. Relevant indicators were assessed through biochemical experiments.
RESULTS
In the LID model of 6-OHDA rats, ONO-2506 significantly delayed the development and reduced the degree of abnormal involuntary movement in the early stage of L-DOPA treatment and increased glial fibrillary acidic protein and glutamate transporter 1 (GLT-1) expression in the striatum compared to saline. However, there was no significant difference in the improvement in motor function between the ONO-2506 and saline groups.
CONCLUSIONS
ONO-2506 delays the emergence of L-DOPA-induced abnormal involuntary movements in the early stage of L-DOPA administration, without affecting the anti-PD effect of L-DOPA. The delaying effect of ONO-2506 on LID may be linked to the increased expression of GLT-1 in the rat striatum. Interventions targeting astrocytes and glutamate transporters are potential therapeutic strategies to delay the development of LID.
Topics: Rats; Animals; Levodopa; Oxidopamine; Dyskinesia, Drug-Induced; Parkinson Disease; Corpus Striatum; Disease Models, Animal; Antiparkinson Agents
PubMed: 36796751
DOI: 10.1016/j.neuroscience.2023.02.004 -
International Journal of Molecular... Feb 2023The pathogenesis of Parkinson's disease (PD) is very complex and still needs further exploration. Leucine-rich repeat kinase 2 (LRRK2) is associated with familial PD in...
The pathogenesis of Parkinson's disease (PD) is very complex and still needs further exploration. Leucine-rich repeat kinase 2 (LRRK2) is associated with familial PD in mutant forms and sporadic PD in the wild-type form. Abnormal iron accumulation is found in the substantia nigra of PD patients, but its exact effects are not very clear. Here, we show that iron dextran exacerbates the neurological deficit and loss of dopaminergic neurons in 6-OHDA lesioned rats. 6-OHDA and ferric ammonium citrate (FAC) significantly increase the activity of LRRK2 as reflected by the phosphorylation of LRRK2, at S935 and S1292 sites. 6-OHDA-induced LRRK2 phosphorylation is attenuated by the iron chelator deferoxamine, especially at the S1292 site. 6-OHDA and FAC markedly induce the expression of pro-apoptotic molecules and the production of ROS by activating LRRK2. Furthermore, G2019S-LRRK2 with high kinase activity showed the strongest absorptive capacity for ferrous iron and the highest intracellular iron content among WT-LRRK2, G2019S-LRRK2, and kinase-inactive D2017A-LRRK2 groups. Taken together, our results demonstrate that iron promotes the activation of LRRK2, and active LRRK2 accelerates ferrous iron uptake, suggesting that there exists an interplay between iron and LRRK2 in dopaminergic neurons, providing a new perspective to uncover the underlying mechanisms of PD occurrence.
Topics: Animals; Rats; Dopaminergic Neurons; Iron; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Oxidopamine; Parkinson Disease; Substantia Nigra; Disease Models, Animal
PubMed: 36835121
DOI: 10.3390/ijms24043709 -
Cells Nov 2023Parkinson's disease (PD) is the most common movement disorder, characterized by the progressive loss of dopaminergic neurons from the nigrostriatal system. Currently,...
Treating Parkinson's Disease with Human Bone Marrow Mesenchymal Stem Cell Secretome: A Translational Investigation Using Human Brain Organoids and Different Routes of In Vivo Administration.
Parkinson's disease (PD) is the most common movement disorder, characterized by the progressive loss of dopaminergic neurons from the nigrostriatal system. Currently, there is no treatment that retards disease progression or reverses damage prior to the time of clinical diagnosis. Mesenchymal stem cells (MSCs) are one of the most extensively studied cell sources for regenerative medicine applications, particularly due to the release of soluble factors and vesicles, known as secretome. The main goal of this work was to address the therapeutic potential of the secretome collected from bone-marrow-derived MSCs (BM-MSCs) using different models of the disease. Firstly, we took advantage of an optimized human midbrain-specific organoid system to model PD in vitro using a neurotoxin-induced model through 6-hydroxydopamine (6-OHDA) exposure. In vivo, we evaluated the effects of BM-MSC secretome comparing two different routes of secretome administration: intracerebral injections (a two-site single administration) against multiple systemic administration. The secretome of BM-MSCs was able to protect from dopaminergic neuronal loss, these effects being more evident in vivo. The BM-MSC secretome led to motor function recovery and dopaminergic loss protection; however, multiple systemic administrations resulted in larger therapeutic effects, making this result extremely relevant for potential future clinical applications.
Topics: Humans; Parkinson Disease; Secretome; Brain; Oxidopamine; Organoids; Mesenchymal Stem Cells
PubMed: 37947643
DOI: 10.3390/cells12212565 -
European Surgical Research. Europaische... 2023Evidence-based grading of the impact of intracranial surgery on rat's well-being is important for ethical and legal reasons. We assessed the severity of complex and...
INTRODUCTION
Evidence-based grading of the impact of intracranial surgery on rat's well-being is important for ethical and legal reasons. We assessed the severity of complex and repeated intracranial surgery in a 6-hydroxydopamine (6-OHDA) Parkinson's rat model with subsequent intracranial electrode implantation and in an intracranial tumor model with subsequent resection.
METHODS
Stereotactic surgery was performed in adult male rats with the same general anesthesia and perioperative pain management. In Parkinson's model, Sprague Dawley rats received unilateral injection of 6-OHDA (n = 11) or vehicle (n = 7) into the medial forebrain bundle as first operation (1st OP). After four weeks, neural electrodes were implanted in all rats as second operation (2nd OP). For tumor formation, BDIX/UlmHanZtm rats (n = 8) received frontocortical injection of BT4Ca cells as 1st OP, followed by tumor resection as 2nd OP after one week. Multiple measures severity assessment was done two days before and four days after surgery in all rats, comprising clinical scoring, body weight, and detailed behavioral screening. To include a condition with a known burden, rats with intracranial tumors were additionally assessed up to a predefined humane endpoint that has previously been classified as "moderate".
RESULTS
After the 1st OP, only 6-OHDA injection resulted in transient elevated clinical scores, a mild long-lasting weight reduction, and motor disturbances. After the second surgery, body weight was transiently reduced in all groups. All other parameters showed variable results. Principal component analysis showed a separation from the preoperative state driven by motor-related parameters after 6-OHDA injection, while separation after electrode implantation and more clearly after tumor resection was driven by pain-related parameters, although not reaching the level of the humane endpoint of our tumor model.
CONCLUSION
Overall, cranial surgery of different complexity only transiently and rather mildly affects rat's well-being. Multiple measures assessment allows the differentiation of model-related motor disturbances in Parkinson's model from potentially pain-related conditions after tumor resection and electrode implantation.
Topics: Rats; Male; Animals; Rats, Sprague-Dawley; Oxidopamine; Parkinson Disease; Body Weight; Disease Models, Animal
PubMed: 34731861
DOI: 10.1159/000520678 -
PloS One 2023Caenorhabditis elegans (C. elegans) has served as a simple model organism to study dopaminergic neurodegeneration, as it enables quantitative analysis of cellular and...
Caenorhabditis elegans (C. elegans) has served as a simple model organism to study dopaminergic neurodegeneration, as it enables quantitative analysis of cellular and sub-cellular morphologies in live animals. These isogenic nematodes have a rapid life cycle and transparent body, making high-throughput imaging and evaluation of fluorescently tagged neurons possible. However, the current state-of-the-art method for quantifying dopaminergic degeneration requires researchers to manually examine images and score dendrites into groups of varying levels of neurodegeneration severity, which is time consuming, subject to bias, and limited in data sensitivity. We aim to overcome the pitfalls of manual neuron scoring by developing an automated, unbiased image processing algorithm to quantify dopaminergic neurodegeneration in C. elegans. The algorithm can be used on images acquired with different microscopy setups and only requires two inputs: a maximum projection image of the four cephalic neurons in the C. elegans head and the pixel size of the user's camera. We validate the platform by detecting and quantifying neurodegeneration in nematodes exposed to rotenone, cold shock, and 6-hydroxydopamine using 63x epifluorescence, 63x confocal, and 40x epifluorescence microscopy, respectively. Analysis of tubby mutant worms with altered fat storage showed that, contrary to our hypothesis, increased adiposity did not sensitize to stressor-induced neurodegeneration. We further verify the accuracy of the algorithm by comparing code-generated, categorical degeneration results with manually scored dendrites of the same experiments. The platform, which detects 20 different metrics of neurodegeneration, can provide comparative insight into how each exposure affects dopaminergic neurodegeneration patterns.
Topics: Animals; Caenorhabditis elegans; Animals, Genetically Modified; Dopamine; Caenorhabditis elegans Proteins; Oxidopamine; Dopaminergic Neurons
PubMed: 37418455
DOI: 10.1371/journal.pone.0281797 -
Molecular and Cellular Neurosciences May 2022The sympathetic nervous system (SNS) regulates skeletal muscle motor innervation and stabilizes the NMJ in health, disease and aging. Previous studies using both...
The sympathetic nervous system (SNS) regulates skeletal muscle motor innervation and stabilizes the NMJ in health, disease and aging. Previous studies using both chemical (6-hydroxydopamine, 6-OHDA) and microsurgically-induced sympathetic denervation examined the NMJ organization and transmission in the mouse; however, a detailed quantification of the postterminal on larger hindlimb muscles involved in gait mechanics and posture is lacking. The purpose of this study was to determine whether targets of the sympathetic neuron (SN) exhibiting different intrinsic composition such as the fast-twitch extensor digitorum longus (EDL) and the slow-twitch soleus muscles differ in their response to SN deprivation, and to develop a strategy to accurately quantify the impact of sympathectomy on the NMJ postterminal including those fibers located deeper in the muscle. This approach included muscle fixed ex vivo or through transcardial perfusion in mice treated with 6-OHDA or control ascorbic acid. We measured NMJ postterminal mean terminal total area, number of postterminal fragments, mean fragment area, and mean distance between fragments in free-floating alpha-bungarotoxin-stained in 1038 isolated muscle fibers. We found that muscle fiber sympathetic innervation plays a crucial role in the structural organization of the motorneuron-myofiber synapse postterminal and its deprivation leads to AChR cluster dispersion or shrinking as described in various neuromuscular diseases and aging.
Topics: Animals; Mice; Motor Neurons; Muscle, Skeletal; Neuromuscular Junction; Oxidopamine; Sympathectomy
PubMed: 35489637
DOI: 10.1016/j.mcn.2022.103730 -
Journal of Food and Drug Analysis Jan 2020The incidence of neurodegeneration leading to the conditions such as Alzheimer's and Parkinson's diseases are on the increase, they require the approaches that focus on...
The incidence of neurodegeneration leading to the conditions such as Alzheimer's and Parkinson's diseases are on the increase, they require the approaches that focus on protection prevention rather than treatment. Plants are rich sources of many compounds which possess medicinal properties. We sought to investigate the neuroprotective effects of Uncariahirsuta and its compounds on d-galactose-induced stress in BALB/c mice as well as 6-hydroxydopamine (6-OHDA)-induced stress in mouse nerve growth factor (mNGF)-differentiated PC12 cells. Our results demonstrate that the 95% ethanol extract of U. hirsuta reversed the d-galactose-induced learning and memory dysfunctions and decreased the malodialdehyde levels. Furthermore, the isolated compounds, 5β-carboxystrictosidine (1) and chlorogenic acid (2), protected mNGF-differentiated PC12 cells against toxicity induced by 6-OHDA by acting as antiapoptotic agents. The 50% inhibitory concentration (IC) for intracellular reactive oxygen species (ROS) scavenging was found to be 24.5 (for 1) and 19.7 μM (for 2), and both 1 and 2 reduced intracellular calcium levels with respective IC values of 46.9 and 27 μM. Interestingly, both compounds inhibited caspase 3 and 9 activities with respective IC values of 25.6 and 24.5 μM for 1 and 19.4 and 16.3 μM for 2. Our results identify U. hirsuta and its active compounds as potential neuroprotective agents and deserve further evaluation for drug development for neuroprotection in the future.
Topics: Animals; Cell Survival; Learning; Memory; Mice; Mice, Inbred BALB C; Neuroprotective Agents; Oxidative Stress; Oxidopamine; PC12 Cells; Plant Extracts; Rats; Reactive Oxygen Species; Uncaria
PubMed: 31883603
DOI: 10.1016/j.jfda.2019.10.004 -
Yakugaku Zasshi : Journal of the... 2013Parkinson disease is one of the most common neurodegenerative disorders and is characterized by the selective loss of dopaminergic neurons in the substantia nigra.... (Review)
Review
Parkinson disease is one of the most common neurodegenerative disorders and is characterized by the selective loss of dopaminergic neurons in the substantia nigra. Although a decrease in proteasome activity has been found in patients with sporadic Parkinson disease, the relationship between the ubiquitin-proteasome system and dopaminergic neuronal death remains to be elucidated. Here, we review a mechanism in which proteasome inhibition provides dopaminergic neuroprotection from oxidative stress. Treatment with lactacystin, a proteasome inhibitor, significantly suppressed 6-hydroxydopamine (6-OHDA)-induced toxicity and oxidative stress in PC12 cells. In addition, lactacystin enhanced glutathione synthesis via elevation of γ-glutamylcysteine synthetase (γ-GCS) mRNA levels. Expression of antioxidant enzymes, such as γ-GCS and hemeoxygenase-1 (HO-1), is regulated by the nuclear factor-erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway. Lactacystin induced Nrf2 accumulation and increased ARE activity. In mesencephalic cultures, lactacystin-induced upregulation of HO-1 in astrocytes contributed to dopaminergic neuroprotection against 6-OHDA-induced toxicity. These data suggest that proteasome inhibition provides cytoprotection against oxidative stress by activating the Nrf2-ARE pathway. Subsequently, we attempted to identify a novel Nrf2-ARE activator in dietary fruits and vegetables. Using bioactivity-guided fractionation, we identified 2',3'-dihydroxy-4',6'-dimethoxychalcone (DDC) from green perilla leaves as the activator responsible for the increased activation of the ARE pathway. DDC upregulated γ-GCS and HO-1 and protected PC12 cells against 6-OHDA-induced toxicity. In conclusion, the activation of the Nrf2-ARE pathway may be an effective means to prevent dopaminergic neuronal death in patients with Parkinson disease.
Topics: Acetylcysteine; Animals; Antioxidant Response Elements; Cell Death; Chalcones; Dopaminergic Neurons; NF-E2-Related Factor 2; Oxidative Stress; Oxidopamine; Parkinson Disease; Perilla; Proteasome Endopeptidase Complex; Rats
PubMed: 23995806
DOI: 10.1248/yakushi.13-00166 -
Clinics (Sao Paulo, Brazil) 2023The 6-OHDA nigro-striatal lesion model has already been related to disorders in the excitability and synchronicity of neural networks and variation in the expression of...
BACKGROUND
The 6-OHDA nigro-striatal lesion model has already been related to disorders in the excitability and synchronicity of neural networks and variation in the expression of transmembrane proteins that control intra and extracellular ionic concentrations, such as cation-chloride cotransporters (NKCC1 and KCC2) and Na+/K+-ATPase and, also, to the glial proliferation after injury. All these non-synaptic mechanisms have already been related to neuronal injury and hyper-synchronism processes.
OBJECTIVE
The main objective of this study is to verify whether mechanisms not directly related to synaptic neurotransmission could be involved in the modulation of nigrostriatal pathways.
METHODS
Male Wistar rats, 3 months old, were submitted to a unilateral injection of 24 µg of 6-OHDA, in the striatum (n = 8). The animals in the Control group (n = 8) were submitted to the same protocol, with the replacement of 6-OHDA by 0.9% saline. The analysis by optical densitometry was performed to quantify the immunoreactivity intensity of GFAP, NKCC1, KCC2, Na+/K+-ATPase, TH and Cx36.
RESULTS
The 6-OHDA induced lesions in the striatum, were not followed by changes in the expression cation-chloride cotransporters and Na+/K+-ATPase, but with astrocytic reactivity in the lesioned and adjacent regions of the nigrostriatal. Moreover, the dopaminergic degeneration caused by 6-OHDA is followed by changes in the expression of connexin-36.
CONCLUSIONS
The use of the GJ blockers directly along the nigrostriatal pathways to control PD motor symptoms is conjectured. Electrophysiology of the striatum and the substantia nigra, to verify changes in neuronal synchronism, comparing brain slices of control animals and experimental models of PD, is needed.
Topics: Rats; Animals; Male; Parkinson Disease; Oxidopamine; Rats, Wistar; Chlorides; Disease Models, Animal; Adenosine Triphosphatases; Symporters
PubMed: 37480642
DOI: 10.1016/j.clinsp.2023.100242 -
Parkinsonism & Related Disorders Jun 2020Brain organoids are highly complex multi-cellular tissue proxies, which have recently risen as novel tools to study neurodegenerative diseases such as Parkinson's...
INTRODUCTION
Brain organoids are highly complex multi-cellular tissue proxies, which have recently risen as novel tools to study neurodegenerative diseases such as Parkinson's disease (PD). However, with increasing complexity of the system, usage of quantitative tools becomes challenging.
OBJECTIVES
The primary objective of this study was to develop a neurotoxin-induced PD organoid model and to assess the neurotoxic effect on dopaminergic neurons using microscopy-based phenotyping in a high-content fashion.
METHODS
We describe a pipeline for a machine learning-based analytical method, allowing for detailed image-based cell profiling and toxicity prediction in brain organoids treated with the neurotoxic compound 6-hydroxydopamine (6-OHDA).
RESULTS
We quantified features such as dopaminergic neuron count and neuronal complexity and built a machine learning classifier with the data to optimize data processing strategies and to discriminate between different treatment conditions. We validated the approach with high content imaging data from PD patient derived midbrain organoids.
CONCLUSIONS
The here described model is a valuable tool for advanced in vitro PD modeling and to test putative neurotoxic compounds.
Topics: Dopaminergic Neurons; Flow Cytometry; Humans; Induced Pluripotent Stem Cells; Machine Learning; Mesencephalon; Microscopy, Confocal; Neurotoxicity Syndromes; Organoids; Oxidopamine; Proof of Concept Study
PubMed: 32534431
DOI: 10.1016/j.parkreldis.2020.05.011