TET2-mediated Cdkn2A DNA hydroxymethylation in midbrain dopaminergic neuron injury of Parkinson’s disease

Abstract It has been reported that abnormal epigenetic modification is associated with the occurrence of Parkinson’s disease (PD). Here, we found that a ten-eleven translocation 2 (TET2), a staff of the DNA hydroxylases family, was increased in dopaminergic neurons in vitro and in vivo. Genome-wide mapping of DNA 5-hydroxymethylcytosine (5-hmC)-sequencing has revealed an aberrant epigenome 5-hmC landscape in 1-methyl-4-phenylpyridinium iodide (MPP+)-induced SH-SY5Y cells. The TET family of DNA hydroxylases could reverse DNA methylation by oxidization of 5-methylcytosine (5-mC) to 5-hmC. However, the relationship between modification of DNA hydroxymethylation and the pathogenesis of PD is not clear. According to the results of 5-hmC-sequencing studies, 5-hmC was associated with gene-rich regions in the genomes related to cell cycle, especially gene-cyclin-dependent kinase inhibitor 2A (Cdkn2A). Downregulation of TET2 expression could significantly rescue MPP+-stimulated SH-SY5Y cell damage and cell cycle arrest. Meanwhile, knockdown of Tet2 expression in the substantia nigra pars compacta of MPTP-induced PD mice resulted in attenuated MPTP-induced motor deficits and dopaminergic neuronal injury via p16 suppression. In this study, we demonstrated a critical function of TET2 in PD development via the CDKN2A activity-dependent epigenetic pathway, suggesting a potential new strategy for epigenetic therapy.

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Emerging regenerative medicine and tissue engineering strategies for Parkinson’s disease

npj Parkinson s Disease ◽

10.1038/s41531-019-0105-5 ◽

2020 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

James P. Harris ◽

Justin C. Burrell ◽

Laura A. Struzyna ◽

H. Isaac Chen ◽

Mijail D. Serruya ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Regenerative Medicine ◽

Treatment Strategies ◽

Current Treatment ◽

Substantia Nigra Pars Compacta ◽

Patient Specific ◽

Motor Deficits ◽

Nigrostriatal Pathway ◽

Future Challenges

AbstractParkinson’s disease (PD) is the second most common progressive neurodegenerative disease, affecting 1–2% of people over 65. The classic motor symptoms of PD result from selective degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc), resulting in a loss of their long axonal projections to the striatum. Current treatment strategies such as dopamine replacement and deep brain stimulation (DBS) can only minimize the symptoms of nigrostriatal degeneration, not directly replace the lost pathway. Regenerative medicine-based solutions are being aggressively pursued with the goal of restoring dopamine levels in the striatum, with several emerging techniques attempting to reconstruct the entire nigrostriatal pathway—a key goal to recreate feedback pathways to ensure proper dopamine regulation. Although many pharmacological, genetic, and optogenetic treatments are being developed, this article focuses on the evolution of transplant therapies for the treatment of PD, including fetal grafts, cell-based implants, and more recent tissue-engineered constructs. Attention is given to cell/tissue sources, efficacy to date, and future challenges that must be overcome to enable robust translation into clinical use. Emerging regenerative medicine therapies are being developed using neurons derived from autologous stem cells, enabling the construction of patient-specific constructs tailored to their particular extent of degeneration. In the upcoming era of restorative neurosurgery, such constructs may directly replace SNpc neurons, restore axon-based dopaminergic inputs to the striatum, and ameliorate motor deficits. These solutions may provide a transformative and scalable solution to permanently replace lost neuroanatomy and improve the lives of millions of people afflicted by PD.

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The Nrf2-NLRP3-Caspase1 axis mediates the neuroprotective effects of Celastrol in Parkinson's disease

10.21203/rs.3.rs-50111/v1 ◽

2020 ◽

Author(s):

Chenyu Zhang ◽

Miao Zhao ◽

Bingwei Wang ◽

Zhijie Su ◽

Bingbing Guo ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dopaminergic Neurons ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Inflammasome Activation ◽

Sequencing Analysis ◽

Pentacyclic Triterpene ◽

Neuroprotective Effects ◽

Neuroprotective Actions

Abstract Background: Parkinson’s disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNc), accompanied by chronic neuroinflammation, oxidative stress, and widespread accumulation of α-synuclein. Celastrol (Cel), a potent anti-inflammatory and anti-oxidative pentacyclic triterpene, has emerged as a neuroprotective agent. However, the mechanisms by which celastrol is neuroprotective in PD has not yet been elucidated. Methods: The MPTP and AAV-mediated human wild-type α-syn overexpression within SNc induced PD mouse models were employed in this study. By using multiple genetically modified mice (Nrf2-KO, NLRP3-KO and Caspase1-KO), we identified that celastrol effectively inhibited the NLRP3 inflammasome activation, mitigated motor deficits and nigrostriatal dopaminergic degeneration through Nrf2-NLRP3-Caspase1 pathway. Results: Here we show that celastrol protected against the loss of dopaminergic neurons, mitigated the neuroinflammation and motor deficits in both MPTP-induced PD mouse model and AAV-mediated human α-syn overexpression PD model. Whole-genome deep sequencing analysis reveals that Nrf2, NLRP3 and Caspase1 in SNc may be associated with the neuroprotective actions of celastrol in PD. Conclusions: These findings suggest that Nrf2-NLRP3-Caspase1 axis may be a key target of celastrol in PD treatment, and highlight the favorable properties linked to neuroprotection of celastrol, making celastrol as a promising disease-modifying agent for PD.

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Alpha-synuclein promotes dopaminergic neuron death in Parkinson’s disease through microglial and NLRP3 activation

USURJ University of Saskatchewan Undergraduate Research Journal ◽

10.32396/usurj.v6i2.425 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Sarah Klein

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Nlrp3 Inflammasome ◽

Neurodegenerative Disorder ◽

Alpha Synuclein ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Inflammasome Activation ◽

Neuron Death ◽

Nlrp3 Inflammasome Activation

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that involves the death of dopaminergic neurons in the substantia nigra pars compacta (SNpc). After neuronal death, the subsequent reduction of dopamine levels in the brain induces motor deficits characteristic of this hypokinetic disorder. Although there is currently no known cause of PD, alpha-synuclein appears to have a prominent role in both microglial and NLRP3 inflammasome activation. The consequential release of the pro-inflammatory cytokine interleukin-1β (IL-1β) has been demonstrated to be responsible for neuroinflammation and neurodegeneration in PD. The present review highlights the role of alpha-synuclein aggregates in Parkinson’s disease pathogenesis. The PD alpha-synuclein preformed fibril (PFF) animal model permits the specific targeting of alpha-synuclein-mediated microglial and NLRP3 inflammasome activation in newly designed therapies. Studies using this model suggest MCC950 and its analogs as a potential new treatment to prevent neurodegeneration in Parkinson’s disease.

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Chondroitinase ABC reduces dopaminergic nigral cell death and striatal terminal loss in a 6-hydroxydopamine partial lesion mouse model of Parkinson’s disease

BMC Neuroscience ◽

10.1186/s12868-019-0543-3 ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Edward J. R. Fletcher ◽

Lawrence D. F. Moon ◽

Susan Duty

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Chondroitin Sulphate ◽

Neurological Injury ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Chondroitinase Abc ◽

Chondroitin Sulphate Proteoglycans ◽

Partial Lesion ◽

6 Hydroxydopamine

Abstract Background Parkinson’s disease (PD) is characterised by dopaminergic cell loss within the substantia nigra pars compacta (SNc) that leads to reduced striatal dopamine content and resulting motor deficits. Identifying new strategies to protect these cells from degeneration and retain striatal dopaminergic innervation is therefore of great importance. Chondroitin sulphate proteoglycans (CSPGs) are recognised contributors to the inhibitory extracellular milieu known to hinder tissue recovery following CNS damage. Digestion of these molecules by the bacterial lyase chondroitinase ABC (ChABC) has been shown to promote functional recovery in animal models of neurological injury. Although ChABC has been shown to promote sprouting of dopaminergic axons following transection of the nigrostriatal pathway, its ability to protect against nigrostriatal degeneration in a toxin-based module with better construct validity for PD has yet to be explored. Here we examined the neuroprotective efficacy of ChABC treatment in the full and partial 6-hydroxydopamine (6-OHDA) lesion mouse models of PD. Results In mice bearing a full 6-OHDA lesion, ChABC treatment failed to protect against the loss of either nigral cells or striatal terminals. In contrast, in mice bearing a partial 6-OHDA lesion, ChABC treatment significantly protected cells of the rostral SNc, which remained at more than double the numbers seen in vehicle-treated animals. In the partial lesion model, ChABC treatment also significantly preserved dopaminergic fibres of the rostral dorsal striatum which increased from 15.3 ± 3.5% of the intact hemisphere in saline-treated animals to 36.3 ± 6.5% in the ChABC-treated group. These protective effects of ChABC treatment were not accompanied by improvements in either the cylinder or amphetamine-induced rotations tests of motor function. Conclusions ChABC treatment provided significant protection against a partial 6-OHDA lesion of the nigrostriatal tract although the degree of protection was not sufficient to improve motor outcomes. These results support further investigations into the benefits of ChABC treatment for providing neuroprotection in PD.

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Chronic Systemic Exposure to Low-Dose Rotenone Induced Central and Peripheral Neuropathology and Motor Deficits in Mice: Reproducible Animal Model of Parkinson’s Disease

International Journal of Molecular Sciences ◽

10.3390/ijms21093254 ◽

2020 ◽

Vol 21 (9) ◽

pp. 3254 ◽

Cited By ~ 5

Author(s):

Ikuko Miyazaki ◽

Nami Isooka ◽

Fuminori Imafuku ◽

Jin Sun ◽

Ryo Kikuoka ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Mouse Model ◽

Myenteric Plexus ◽

Low Dose ◽

Cholinergic Neurons ◽

Systemic Exposure ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Motor Nucleus

Epidemiological studies demonstrated that pesticide exposure, such as rotenone and paraquat, increases the risk of Parkinson’s disease (PD). Chronic systemic exposure to rotenone, a mitochondrial complex I inhibitor, could reproduce many features of PD. However, the adoption of the models is limiting because of variability in animal sensitivity and the inability of other investigators to consistently reproduce the PD neuropathology. In addition, most of rotenone models were produced in rats. Here, we tried to establish a high-reproducible rotenone model using C57BL/6J mice. The rotenone mouse model was produced by chronic systemic exposure to a low dose of rotenone (2.5 mg/kg/day) for 4 weeks by subcutaneous implantation of rotenone-filled osmotic mini pump. The rotenone-treated mice exhibited motor deficits assessed by open field, rotarod and cylinder test and gastrointestinal dysfunction. Rotenone treatment decreased the number of dopaminergic neuronal cells in the substantia nigra pars compacta (SNpc) and lesioned nerve terminal in the striatum. In addition, we observed significant reduction of cholinergic neurons in the dorsal motor nucleus of the vagus (DMV) and the intestinal myenteric plexus. Moreover, α-synuclein was accumulated in neuronal soma in the SNpc, DMV and intestinal myenteric plexus in rotenone-treated mice. These data suggest that the low-dose rotenone mouse model could reproduce behavioral and central and peripheral neurodegenerative features of PD and be a useful model for investigation of PD pathogenesis.

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DNAJB6 Suppresses Alpha-synuclein Induced Pathology in an Animal Model of Parkinson’s Disease

10.21203/rs.3.rs-112939/v1 ◽

2020 ◽

Author(s):

Sertan Arkan ◽

Mårten Ljungberg ◽

Deniz Kirik ◽

Christian Hansen

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Animal Model ◽

Cell Death ◽

Alpha Synuclein ◽

Cellular Level ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Dopaminergic Cell ◽

Knock Out

Abstract Background: α-synuclein (α-syn) aggregation can lead to degeneration of dopaminergic neurons in the substantia nigra pars compacta ( SNpc ) as invariably observed in patients with Parkinson’s Disease (PD). The co-chaperone DNAJB6 has previously been found to be expressed at higher levels in PD patients than in control subjects and was also found in Lewy bodies. Our previous experiments showed that knock out of DNAJB6 induced α-syn aggregation in cellular level. However, effects of overexpression of DNAJB6 against α-syn aggregation remains to be investigated. Methods: we used to α-syn CFP/YFP HEK293 FRET cell line to investigate the effects of overexpression of DNAJB6 in cellular level. α-syn aggregation was induced by transfection α-syn preformed fibrils (PPF), then was measured FRET analysis. We proceeded to investigate if DNAJB6b can impair α-syn aggregation and toxicity in an animal model and used adeno associated vira (AAV6) designed to overexpress of human wt α-syn, GFP-DNAJB6 or GFP in rats. These vectors were injected into the SNpc of the rats, unilaterally. Rats injected with vira to express α-syn along with GFP in the SNpc where compared to rats expressing α-syn and GFP-DNAJB6. We evaluated motor functions, dopaminergic cell death, phosphorylated α-syn in SNpc and axonal degeneration in striatum. Results : We show that DNAJB6 prevent α-syn aggregation induced by α-syn PFF’s, in a cell culture model. Also, we observed α-syn overexpression caused dopaminergic cell death and that this was strongly reduced by co-expression of DNAJB6b. In addition, the lesion caused by α-syn overexpression resulted in behavior deficits, which increased over time as seen in stepping test, which was rescued by co-expression of DNAJB6b. Moreover, we observed an increase in serine 129 (S129) phosphorylated α-syn in SNpc of rats overexpressing α-syn, that was lowered by DNAJB6 co-expression. Conclusion : We here demonstrate for the first time that DNAJB6 is a strong suppressor of α-syn aggregation in cells and in animals and that this results in a suppression of dopaminergic cell death and PD related motor deficits in an animal model of PD. Keywords: Protein homeostasis, Parkinson`s Disease, Alpha-synuclein, Adeno Associated Virus, DNAJB6, Heat Shock Protein 70

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The Pathopharmacological Interplay between Vanadium and Iron in Parkinson’s Disease Models

International Journal of Molecular Sciences ◽

10.3390/ijms21186719 ◽

2020 ◽

Vol 21 (18) ◽

pp. 6719

Author(s):

Samuel Ohiomokhare ◽

Francis Olaolorun ◽

Amany Ladagu ◽

Funmilayo Olopade ◽

Melanie-Jayne R. Howes ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Iron Chelation ◽

Symptomatic Treatment ◽

Iron Chelator ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Environmental Toxicants ◽

Nigrostriatal Pathway ◽

Cad Cells

Parkinson’s disease (PD) pathology is characterised by distinct types of cellular defects, notably associated with oxidative damage and mitochondria dysfunction, leading to the selective loss of dopaminergic neurons in the brain’s substantia nigra pars compacta (SNpc). Exposure to some environmental toxicants and heavy metals has been associated with PD pathogenesis. Raised iron levels have also been consistently observed in the nigrostriatal pathway of PD cases. This study explored, for the first time, the effects of an exogenous environmental heavy metal (vanadium) and its interaction with iron, focusing on the subtoxic effects of these metals on PD-like oxidative stress phenotypes in Catecholaminergic a-differentiated (CAD) cells and PTEN-induced kinase 1 (PINK−1)B9Drosophila melanogaster models of PD. We found that undifferentiated CAD cells were more susceptible to vanadium exposure than differentiated cells, and this susceptibility was modulated by iron. In PINK−1 flies, the exposure to chronic low doses of vanadium exacerbated the existing motor deficits, reduced survival, and increased the production of reactive oxygen species (ROS). Both Aloysia citrodora Paláu, a natural iron chelator, and Deferoxamine Mesylate (DFO), a synthetic iron chelator, significantly protected against the PD-like phenotypes in both models. These results favour the case for iron-chelation therapy as a viable option for the symptomatic treatment of PD.

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To be or not to be pink(1): contradictory findings in an animal model for Parkinson’s disease

Brain Communications ◽

10.1093/braincomms/fcz016 ◽

2019 ◽

Vol 1 (1) ◽

Cited By ~ 2

Author(s):

Ria de Haas ◽

Lisa C M W Heltzel ◽

Denise Tax ◽

Petra van den Broek ◽

Hilbert Steenbreker ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Animal Model ◽

Substantia Nigra ◽

Dopaminergic Neurons ◽

In Vivo Microdialysis ◽

Substantia Nigra Pars Compacta ◽

Laboratory Animals ◽

Motor Deficits

Abstract The PTEN-induced putative kinase 1 knockout rat (Pink1−/−) is marketed as an established model for Parkinson’s disease, characterized by development of motor deficits and progressive degeneration of half the dopaminergic neurons in the substantia nigra pars compacta by 8 months of age. In this study, we address our concerns about the reproducibility of the Pink1−/− rat model. We evaluated behavioural function, number of substantia nigra dopaminergic neurons and extracellular striatal dopamine concentrations by in vivo microdialysis. Strikingly, we and others failed to observe any loss of dopaminergic neurons in 8-month-old male Pink1−/− rats. To understand this variability, we compared key experimental parameters from the different studies and provide explanations for contradictory findings. Although Pink1−/− rats developed behavioural deficits, these could not be attributed to nigrostriatal degeneration as there was no loss of dopaminergic neurons in the substantia nigra and no changes in neurotransmitter levels in the striatum. To maximize the benefit of Parkinson’s disease research and limit the unnecessary use of laboratory animals, it is essential that the research community is aware of the limits of this animal model. Additional research is needed to identify reasons for inconsistency between Pink1−/− rat colonies and why degeneration in the substantia nigra is not consistent.

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The DJ1-Nrf2-STING axis mediates the neuroprotective effects of Withaferin A in Parkinson’s disease

Cell Death and Differentiation ◽

10.1038/s41418-021-00767-2 ◽

2021 ◽

Author(s):

Miao Zhao ◽

Bingwei Wang ◽

Chenyu Zhang ◽

Zhijie Su ◽

Bingbing Guo ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dopaminergic Neurons ◽

Substantia Nigra Pars Compacta ◽

Withaferin A ◽

Motor Deficits ◽

Whole Genome ◽

Potential Candidate ◽

Sequencing Analysis ◽

Neuroprotective Effects

AbstractThe pathogenesis of Parkinson’s disease (PD) remains unclear, and there is no disease-modifying agent for PD. Withaferin A (WA), a naturally occurring compound, has emerged as a neuroprotective agent. However, the mechanisms by which WA is neuroprotective in PD are unknown. Here we show that WA protected against loss of dopaminergic neurons, neuroinflammation, and motor deficits in MPTP-induced PD mouse models. Whole-genome deep sequencing analysis combined with Meta-analysis of human PD studies reveal that DJ1, Nrf2, and STING in substantia nigra pars compacta (SNc) are linked to anti-PD effect of WA. We found that WA activated DJ1 and Nrf2, and suppressed STING within SNc; and overexpression of STING in SNc dampened the effect of WA. Using genetically modified mice (DJ1-KO, Nrf2-KO, STINGgt/gt and STING-KO) and immunolabeling technique, we identified that WA targeted DJ1-Nrf2-STING pathway in dopaminergic neurons; and we demonstrate that STING might be an important factor in PD pathogenesis. In addition, WA alleviated accumulation of phosphorylated α-synuclein (p-α-syn) and insoluble α-syn within SNc in adeno-associated virus (AAV)-mediated human α-syn overexpression PD model. Our comparative analysis on whole-genome transcriptome profiles suggests that STING might be a key target of WA and amantadine in PD treatment. This study highlights a multifaceted role for WA in neuroprotection, and suggests that WA can be a potential candidate for treatment of PD.

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Chondroitinase ABC reduces dopaminergic nigral cell death and striatal terminal loss in a 6-hydroxydopamine partial lesion mouse model of Parkinson’s disease

10.21203/rs.2.11345/v1 ◽

2019 ◽

Author(s):

Edward JR Fletc ◽

Lawrence DF Moon ◽

Susan Duty

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Chondroitin Sulphate ◽

Neurological Injury ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Chondroitinase Abc ◽

Chondroitin Sulphate Proteoglycans ◽

Partial Lesion ◽

6 Hydroxydopamine

Abstract Background Parkinson's disease (PD) is characterised by dopaminergic cell loss within the substantia nigra pars compacta (SNc) that leads to reduced striatal dopamine content and resulting motor deficits. Identifying new strategies to protect these cells from degeneration and retain striatal dopaminergic innervation is therefore of great importance. Chondroitin sulphate proteoglycans (CSPGs) are recognised contributors to the inhibitory extracellular milieu known to hinder tissue recovery following CNS damage. Digestion of these molecules by the bacterial lyase chondroitinase ABC (ChABC) has been shown to promote functional recovery in animal models of neurological injury. Although ChABC has been shown to promote sprouting of dopaminergic axons following transection of the nigrostriatal pathway, its ability to protect against nigrostriatal degeneration in a more clinically-relevant toxin model of PD has yet to be explored. Here we examined the neuroprotective efficacy of ChABC treatment in the full and partial 6-hydroxydopamine (6-OHDA) lesion mouse models of PD. Results In mice bearing a full 6-OHDA lesion, ChABC treatment failed to protect against the loss of either nigral cells or striatal terminals. In contrast, in mice bearing a partial 6-OHDA lesion, ChABC treatment significantly protected cells of the rostral SNc, which remained at more than double the numbers seen in vehicle-treated animals. In the partial lesion model, ChABC treatment also significantly preserved dopaminergic fibres of the rostral dorsal striatum which increased from 15.3 ± 3.5% of the intact hemisphere in saline-treated animals to 36.3 ± 6.5% in the ChABC-treated group. These protective effects of ChABC treatment were not accompanied by improvements in either the cylinder or amphetamine-induced rotations tests of motor function. Conclusions ChABC treatment provided significant protection against a partial 6-OHDA lesion of the nigrostriatal tract although the degree of protection was not sufficient to improve motor outcomes. These results support further investigations into the benefits of ChABC treatment for providing neuroprotection in PD.

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