scholarly journals The cell biology of Parkinson’s disease

2021 ◽  
Vol 220 (4) ◽  
Author(s):  
Nikhil Panicker ◽  
Preston Ge ◽  
Valina L. Dawson ◽  
Ted M. Dawson
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Signaling Pathways ◽  
Cell Biology ◽  
Neurodegenerative Disorder ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Cellular Functions ◽  
Neuron Death ◽  
Associated Proteins

Parkinson’s disease (PD) is a progressive neurodegenerative disorder resulting from the death of dopamine neurons in the substantia nigra pars compacta. Our understanding of PD biology has been enriched by the identification of genes involved in its rare, inheritable forms, termed PARK genes. These genes encode proteins including α-syn, LRRK2, VPS35, parkin, PINK1, and DJ1, which can cause monogenetic PD when mutated. Investigating the cellular functions of these proteins has been instrumental in identifying signaling pathways that mediate pathology in PD and neuroprotective mechanisms active during homeostatic and pathological conditions. It is now evident that many PD-associated proteins perform multiple functions in PD-associated signaling pathways in neurons. Furthermore, several PARK proteins contribute to non–cell-autonomous mechanisms of neuron death, such as neuroinflammation. A comprehensive understanding of cell-autonomous and non–cell-autonomous pathways involved in PD is essential for developing therapeutics that may slow or halt its progression.

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

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.

scholarly journals GRP78/BIP/HSPA5 as a Therapeutic Target in Models of Parkinson’s Disease: A Mini Review

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Adaze Bijou Enogieru ◽  
Sylvester Ifeanyi Omoruyi ◽  
Donavon Charles Hiss ◽  
Okobi Eko Ekpo
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Er Stress ◽  
Neurodegenerative Disorder ◽  
Current Knowledge ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Unfolded Protein ◽  
Folded Proteins ◽  
The Unfolded Protein Response

Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by selective loss of dopamine neurons in the substantia nigra pars compacta of the midbrain. Reports from postmortem studies in the human PD brain, and experimental PD models reveal that endoplasmic reticulum (ER) stress is implicated in the pathogenesis of PD. In times of stress, the unfolded or misfolded proteins overload the folding capacity of the ER to induce a condition generally known as ER stress. During ER stress, cells activate the unfolded protein response (UPR) to handle increasing amounts of abnormal proteins, and recent evidence has demonstrated the activation of the ER chaperone GRP78/BiP (78 kDa glucose-regulated protein/binding immunoglobulin protein), which is important for proper folding of newly synthesized and partly folded proteins to maintain protein homeostasis. Although the activation of this protein is essential for the initiation of the UPR in PD, there are inconsistent reports on its expression in various PD models. Consequently, this review article aims to summarize current knowledge on neuroprotective agents targeting the expression of GRP78/BiP in the regulation of ER stress in experimental PD models.

scholarly journals Loss of mitochondrial complex I activity potentiates dopamine neuron death induced by microtubule dysfunction in a Parkinson’s disease model

2011 ◽  
Vol 192 (5) ◽  
pp. 873-882 ◽  
Author(s):  
Won-Seok Choi ◽  
Richard D. Palmiter ◽  
Zhengui Xia
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Complex I ◽  
Dopamine Neuron ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Neuron Death ◽  
Complex I Activity

Mitochondrial complex I dysfunction is regarded as underlying dopamine neuron death in Parkinson’s disease models. However, inactivation of the Ndufs4 gene, which compromises complex I activity, does not affect the survival of dopamine neurons in culture or in the substantia nigra pars compacta of 5-wk-old mice. Treatment with piericidin A, a complex I inhibitor, does not induce selective dopamine neuron death in either Ndufs4+/+ or Ndufs4−/− mesencephalic cultures. In contrast, rotenone, another complex I inhibitor, causes selective toxicity to dopamine neurons, and Ndufs4 inactivation potentiates this toxicity. We identify microtubule depolymerization and the accumulation of cytosolic dopamine and reactive oxygen species as alternative mechanisms underlying rotenone-induced dopamine neuron death. Enhanced rotenone toxicity to dopamine neurons from Ndufs4 knockout mice may involve enhanced dopamine synthesis caused by the accumulation of nicotinamide adenine dinucleotide reduced. Our results suggest that the combination of disrupting microtubule dynamics and inhibiting complex I, either by mutations or exposure to toxicants, may be a risk factor for Parkinson’s disease.

Simvastatin Prevents Neurodegeneration in the MPTP Mouse Model of Parkinson’s Disease via Inhibition of A1 Reactive Astrocytes

2021 ◽  
pp. 1-8
Author(s):  
Ren-Wei Du ◽  
Wen-Guang Bu
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Mouse Model ◽  
Underlying Mechanism ◽  
Reactive Astrocytes ◽  
Dopamine Neurons ◽  
Neuron Death ◽  
Neurologic Disorders

Emerging evidence indicates that A1 reactive astrocytes play crucial roles in the pathogenesis of Parkinson’s disease (PD). Thus, development of agents that could inhibit the formation of A1 reactive astrocytes could be used to treat PD. Simvastatin has been touted as a potential neuroprotective agent for neurologic disorders such as PD, but the specific underlying mechanism remains unclear. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD and primary astrocytes/neurons were prepared to investigate the effects of simvastatin on PD and its underlying mechanisms in vitro and in vivo. We show that simvastatin protects against the loss of dopamine neurons and behavioral deficits in the MPTP mouse model of PD. We also found that simvastatin suppressed the expression of A1 astrocytic specific markers in vivo and in vitro. In addition, simvastatin alleviated neuron death induced by A1 astrocytes. Our findings reveal that simvastatin is neuroprotective via the prevention of conversion of astrocytes to an A1 neurotoxic phenotype. In light of simvastatin favorable properties, it should be evaluated in the treatment of PD and related neurologic disorders characterized by A1 reactive astrocytes.

scholarly journals Combined knockout of Lrrk2 and Rab29 does not result in behavioral abnormalities in vivo

2020 ◽  
Author(s):  
Melissa Conti Mazza ◽  
Victoria Nguyen ◽  
Alexandra Beilina ◽  
Jinhui Ding ◽  
Mark R. Cookson
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Kinase Activity ◽  
Association Studies ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Genome Wide Association Studies ◽  
Double Knockout ◽  
Knockout Mouse Model

AbstractCoding mutations in the LRRK2 gene, encoding for a large protein kinase, have been shown to cause familial Parkinson’s disease (PD). The immediate biological consequence of LRRK2 mutations is to increase kinase activity, leading to the suggestion that inhibition of this enzyme might be useful therapeutically to slow disease progression. Genome-wide association studies have identified the chromosomal loci around LRRK2 and one of its proposed substrates, RAB29, as contributors towards the lifetime risk of sporadic PD. Considering the evidence for interactions between LRRK2 and RAB29 on the genetic and protein levels, here we generated a double knockout mouse model and determined whether there are any consequences on brain function with aging. From a battery of motor and non-motor behavioral tests, we noted only that 18-24 month Rab29-/- and double (Lrrk2-/-/Rab29-/-) knockout mice had diminished locomotor behavior in open field compared to wildtype mice. However, no genotype differences were seen in number of substantia nigra pars compacta (SNc) dopamine neurons or in tyrosine hydroxylase levels in the SNc and striatum, which might reflect a PD-like pathology. These results suggest that depletion of both Lrrk2 and Rab29 is tolerated, at least in mice, and support that this pathway might be able to be safely targeted for therapeutics in humans.Significance statementGenetic variation in LRRK2 that result in elevated kinase activity can cause Parkinson’s disease (PD), suggesting LRRK2 inhibition as a therapeutic strategy. RAB29, a substrate of LRRK2, has also been associated with increased PD risk. Evidence exists for an interactive relationship between LRRK2 and RAB29. Mouse models lacking either LRRK2 or RAB29 do not show brain pathologies. We hypothesized that the loss of both targets would result in additive effects across in vivo and post-mortem assessments in aging mice. We found that loss of both LRRK2 and RAB29 did not result in significant behavioral deficits or dopamine neuron loss. This evidence suggests that chronic inhibition of this pathway should be tolerated clinically.

scholarly journals Potential Role of Caffeine in the Treatment of Parkinson’s Disease

2016 ◽  
Vol 10 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Mohsin H.K. Roshan ◽  
Amos Tambo ◽  
Nikolai P. Pace
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Randomized Clinical Trials ◽  
Neurodegenerative Disorder ◽  
Lewy Bodies ◽  
Substantia Nigra Pars Compacta ◽  
Muscle Rigidity ◽  
Therapeutic Effects ◽  
Motor Symptoms ◽  
Wide Range

Parkinson’s disease [PD] is the second most common neurodegenerative disorder after Alzheimer’s disease, affecting 1% of the population over the age of 55. The underlying neuropathology seen in PD is characterised by progressive loss of dopaminergic neurons in the substantia nigra pars compacta with the presence of Lewy bodies. The Lewy bodies are composed of aggregates of α-synuclein. The motor manifestations of PD include a resting tremor, bradykinesia, and muscle rigidity. Currently there is no cure for PD and motor symptoms are treated with a number of drugs including levodopa [L-dopa]. These drugs do not delay progression of the disease and often provide only temporary relief. Their use is often accompanied by severe adverse effects. Emerging evidence from bothin vivoandin vitrostudies suggests that caffeine may reduce parkinsonian motor symptoms by antagonising the adenosine A2Areceptor, which is predominately expressed in the basal ganglia. It is hypothesised that caffeine may increase the excitatory activity in local areas by inhibiting the astrocytic inflammatory processes but evidence remains inconclusive. In addition, the co-administration of caffeine with currently available PD drugs helps to reduce drug tolerance, suggesting that caffeine may be used as an adjuvant in treating PD. In conclusion, caffeine may have a wide range of therapeutic effects which are yet to be explored, and therefore warrants further investigation in randomized clinical trials.

scholarly journals Molecular Mechanisms Underlying Synaptic and Axon Degeneration in Parkinson’s Disease

2021 ◽  
Vol 15 ◽  
Author(s):  
Nolwazi Z. Gcwensa ◽  
Drèson L. Russell ◽  
Rita M. Cowell ◽  
Laura A. Volpicelli-Daley
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Molecular Mechanisms ◽  
Disease Onset ◽  
Neuronal Cell ◽  
Rem Sleep Behavior Disorder ◽  
Dopamine Neurons ◽  
Neuronal Cell Body ◽  
Substantia Nigra Pars Compacta ◽  
Cognitive Changes

Parkinson’s disease (PD) is a progressive neurodegenerative disease that impairs movement as well as causing multiple other symptoms such as autonomic dysfunction, rapid eye movement (REM) sleep behavior disorder, hyposmia, and cognitive changes. Loss of dopamine neurons in the substantia nigra pars compacta (SNc) and loss of dopamine terminals in the striatum contribute to characteristic motor features. Although therapies ease the symptoms of PD, there are no treatments to slow its progression. Accumulating evidence suggests that synaptic impairments and axonal degeneration precede neuronal cell body loss. Early synaptic changes may be a target to prevent disease onset and slow progression. Imaging of PD patients with radioligands, post-mortem pathologic studies in sporadic PD patients, and animal models of PD demonstrate abnormalities in presynaptic terminals as well as postsynaptic dendritic spines. Dopaminergic and excitatory synapses are substantially reduced in PD, and whether other neuronal subtypes show synaptic defects remains relatively unexplored. Genetic studies implicate several genes that play a role at the synapse, providing additional support for synaptic dysfunction in PD. In this review article we: (1) provide evidence for synaptic defects occurring in PD before neuron death; (2) describe the main genes implicated in PD that could contribute to synapse dysfunction; and (3) show correlations between the expression of Snca mRNA and mouse homologs of PD GWAS genes demonstrating selective enrichment of Snca and synaptic genes in dopaminergic, excitatory and cholinergic neurons. Altogether, these findings highlight the need for novel therapeutics targeting the synapse and suggest that future studies should explore the roles for PD-implicated genes across multiple neuron types and circuits.

scholarly journals Peptide TFP5/TP5 derived from Cdk5 activator P35 provides neuroprotection in the MPTP model of Parkinson’s disease

2015 ◽  
Vol 26 (24) ◽  
pp. 4478-4491 ◽  
Author(s):  
BK. Binukumar ◽  
Varsha Shukla ◽  
Niranjana D. Amin ◽  
Philip Grant ◽  
M. Bhaskar ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurodegenerative Disorder ◽  
Neuroprotective Effect ◽  
Selective Inhibition ◽  
Motor Dysfunction ◽  
Dopamine Neurons ◽  
Dopamine Depletion ◽  
Neuroprotective Effects

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by the loss of dopamine neurons in the substantia nigra, decreased striatal dopamine levels, and consequent extrapyramidal motor dysfunction. Recent evidence indicates that cyclin-dependent kinase 5 (Cdk5) is inappropriately activated in several neurodegenerative conditions, including PD. To date, strategies to specifically inhibit Cdk5 hyperactivity have not been successful without affecting normal Cdk5 activity. Previously we reported that TFP5 peptide has neuroprotective effects in animal models of Alzheimer’s disease. Here we show that TFP5/TP5 selective inhibition of Cdk5/p25 hyperactivation in vivo and in vitro rescues nigrostriatal dopaminergic neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP/MPP+) in a mouse model of PD. TP5 peptide treatment also blocked dopamine depletion in the striatum and improved gait dysfunction after MPTP administration. The neuroprotective effect of TFP5/TP5 peptide is also associated with marked reduction in neuroinflammation and apoptosis. Here we show selective inhibition of Cdk5/p25 ­hyperactivation by TFP5/TP5 peptide, which identifies the kinase as a potential therapeutic target to reduce neurodegeneration in Parkinson’s disease.

Parkinson's Disease Genetics and Pathophysiology

2021 ◽  
Vol 44 (1) ◽  
pp. 87-108
Author(s):  
Gabriel E. Vázquez-Vélez ◽  
Huda Y. Zoghbi
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Genetic Variants ◽  
Neurodegenerative Disorder ◽  
Disease Risk ◽  
Lewy Bodies ◽  
Substantia Nigra Pars Compacta ◽  
Disease Modifying ◽  
Common Neurodegenerative Disorder

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by degeneration of the substantia nigra pars compacta and by accumulation of α-synuclein in Lewy bodies. PD is caused by a combination of environmental factors and genetic variants. These variants range from highly penetrant Mendelian alleles to alleles that only modestly increase disease risk. Here, we review what is known about the genetics of PD. We also describe how PD genetics have solidified the role of endosomal, lysosomal, and mitochondrial dysfunction in PD pathophysiology. Finally, we highlight how all three pathways are affected by α-synuclein and how this knowledge may be harnessed for the development of disease-modifying therapeutics.

scholarly journals Palmitate and Stearate are Increased in the Plasma in a 6-OHDA Model of Parkinson’s Disease

Metabolites ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 31 ◽  
Author(s):  
Anuri Shah ◽  
Pei Han ◽  
Mung-Yee Wong ◽  
Raymond Chang ◽  
Cristina Legido-Quigley
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Stearic Acid ◽  
Palmitic Acid ◽  
Neurodegenerative Disorder ◽  
Motor Dysfunction ◽  
Substantia Nigra Pars Compacta ◽  
Control Group ◽  
Sprague Dawley ◽  
Curative Therapy

Introduction: Parkinson’s disease (PD) is the second most common neurodegenerative disorder, without any widely available curative therapy. Metabolomics is a powerful tool which can be used to identify unexpected pathway-related disease progression and pathophysiological mechanisms. In this study, metabolomics in brain, plasma and liver was investigated in an experimental PD model, to discover small molecules that are associated with dopaminergic cell loss. Methods: Sprague Dawley (SD) rats were injected unilaterally with 6-hydroxydopamine (6-OHDA) or saline for the vehicle control group into the medial forebrain bundle (MFB) to induce loss of dopaminergic neurons in the substantia nigra pars compacta. Plasma, midbrain and liver samples were collected for metabolic profiling. Multivariate and univariate analyses revealed metabolites that were altered in the PD group. Results: In plasma, palmitic acid (q = 3.72 × 10−2, FC = 1.81) and stearic acid (q = 3.84 × 10−2, FC = 2.15), were found to be increased in the PD group. Palmitic acid (q = 3.5 × 10−2) and stearic acid (q = 2.7 × 10−2) correlated with test scores indicative of motor dysfunction. Monopalmitin (q = 4.8 × 10−2, FC = −11.7), monostearin (q = 3.72 × 10−2, FC = −15.1) and myo-inositol (q = 3.81 × 10−2, FC = −3.32), were reduced in the midbrain. The liver did not have altered levels of these molecules. Conclusion: Our results show that saturated free fatty acids, their monoglycerides and myo-inositol metabolism in the midbrain and enteric circulation are associated with 6-OHDA-induced PD pathology.

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