scholarly journals An electrophysiological perspective on Parkinson’s disease: symptomatic pathogenesis and therapeutic approaches

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Lan-Hsin Nancy Lee ◽  
Chen-Syuan Huang ◽  
Hsiang-Hao Chuang ◽  
Hsing-Jung Lai ◽  
Cheng-Kai Yang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Brain Stimulation ◽  
Neuronal Loss ◽  
Substantia Nigra Pars Compacta ◽  
Recent Success ◽  
Cortical Level ◽  
Beta Power ◽  
Locomotor Deficits ◽  
Discharge Patterns

AbstractParkinson’s disease (PD), or paralysis agitans, is a common neurodegenerative disease characterized by dopaminergic deprivation in the basal ganglia because of neuronal loss in the substantia nigra pars compacta. Clinically, PD apparently involves both hypokinetic (e.g. akinetic rigidity) and hyperkinetic (e.g. tremor/propulsion) symptoms. The symptomatic pathogenesis, however, has remained elusive. The recent success of deep brain stimulation (DBS) therapy applied to the subthalamic nucleus (STN) or the globus pallidus pars internus indicates that there are essential electrophysiological abnormalities in PD. Consistently, dopamine-deprived STN shows excessive burst discharges. This proves to be a central pathophysiological element causally linked to the locomotor deficits in PD, as maneuvers (such as DBS of different polarities) decreasing and increasing STN burst discharges would decrease and increase the locomotor deficits, respectively. STN bursts are not so autonomous but show a “relay” feature, requiring glutamatergic synaptic inputs from the motor cortex (MC) to develop. In PD, there is an increase in overall MC activities and the corticosubthalamic input is enhanced and contributory to excessive burst discharges in STN. The increase in MC activities may be relevant to the enhanced beta power in local field potentials (LFP) as well as the deranged motor programming at the cortical level in PD. Moreover, MC could not only drive erroneous STN bursts, but also be driven by STN discharges at specific LFP frequencies (~ 4 to 6 Hz) to produce coherent tremulous muscle contractions. In essence, PD may be viewed as a disorder with deranged rhythms in the cortico-subcortical re-entrant loops, manifestly including STN, the major component of the oscillating core, and MC, the origin of the final common descending motor pathways. The configurations of the deranged rhythms may play a determinant role in the symptomatic pathogenesis of PD, and provide insight into the mechanism underlying normal motor control. Therapeutic brain stimulation for PD and relevant disorders should be adaptively exercised with in-depth pathophysiological considerations for each individual patient, and aim at a final normalization of cortical discharge patterns for the best ameliorating effect on the locomotor and even non-motor symptoms.

scholarly journals When Friendship Turns Sour: Effective Communication Between Mitochondria and Intracellular Organelles in Parkinson's Disease

2020 ◽  
Vol 8 ◽  
Author(s):  
Tsu-Kung Lin ◽  
Kai-Jung Lin ◽  
Kai-Lieh Lin ◽  
Chia-Wei Liou ◽  
Shang-Der Chen ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Stress Responses ◽  
Redox Homeostasis ◽  
Lewy Bodies ◽  
Neuronal Loss ◽  
Physical Contact ◽  
Substantia Nigra Pars Compacta ◽  
Intracellular Organelles ◽  
Pleiotropic Functions

Parkinson's disease (PD) is a complex neurodegenerative disease with pathological hallmarks including progressive neuronal loss from the substantia nigra pars compacta and α-synuclein intraneuronal inclusions, known as Lewy bodies. Although the etiology of PD remains elusive, mitochondrial damage has been established to take center stage in the pathogenesis of PD. Mitochondria are critical to cellular energy production, metabolism, homeostasis, and stress responses; the association with PD emphasizes the importance of maintenance of mitochondrial network integrity. To accomplish the pleiotropic functions, mitochondria are dynamic not only within their own network but also in orchestrated coordination with other organelles in the cellular community. Through physical contact sites, signal transduction, and vesicle transport, mitochondria and intracellular organelles achieve the goals of calcium homeostasis, redox homeostasis, protein homeostasis, autophagy, and apoptosis. Herein, we review the finely tuned interactions between mitochondria and surrounding intracellular organelles, with focus on the nucleus, endoplasmic reticulum, Golgi apparatus, peroxisomes, and lysosomes. Participants that may contribute to the pathogenic mechanisms of PD will be highlighted in this review.

scholarly journals Optogenetic stimulation of glutamatergic neurons in the cuneiform nucleus controls locomotor movements in a mouse model of Parkinson’s disease

2021 ◽  
Author(s):  
Maxime Fougère ◽  
Cornelis Immanuel van der Zouwen ◽  
Joël Boutin ◽  
Kloé Neszvecsko ◽  
Philippe Sarret ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Deep Brain Stimulation ◽  
Mouse Model ◽  
Brain Stimulation ◽  
Glutamatergic Neurons ◽  
Cuneiform Nucleus ◽  
Locomotor Deficits ◽  
Deep Brain ◽  
Stimulation Of

ABSTRACTIn Parkinson’s disease (PD), the loss of midbrain dopaminergic cells results in severe locomotor deficits such a gait freezing and akinesia. Growing evidence indicates that these deficits can be attributed to decreased activity in the Mesencephalic Locomotor Region (MLR), a brainstem region controlling locomotion. Clinicians are exploring deep brain stimulation of the MLR as a treatment option to improve locomotor function. The results are variable, from modest to promising. However, within the MLR, clinicians have targeted the pedunculopontine nucleus exclusively, while leaving the cuneiform nucleus unexplored. To our knowledge, the effects of cuneiform nucleus stimulation have never been determined in parkinsonian conditions in any animal model. Here, we addressed this issue in a mouse model of Parkinson’s disease based on bilateral striatal injection of 6-hydroxydopamine (6-OHDA), which damaged the nigrostriatal pathway and decreased locomotor activity. We show that selective optogenetic stimulation of glutamatergic neurons in the cuneiform nucleus in mice expressing channelrhodopsin in a Cre-dependent manner in Vglut2-positive neurons (Vglut2-ChR2-EYFP mice) increased the number of locomotor initiations, increased the time spent in locomotion, and controlled locomotor speed. Using deep learning-based movement analysis, we found that limb kinematics of optogenetic-evoked locomotion in pathological conditions were largely similar to those recorded in freely moving animals. Our work identifies the glutamatergic neurons of the cuneiform nucleus as a potentially clinically relevant target to improve locomotor activity in parkinsonian conditions. Our study should open new avenues to develop targeted stimulation of these neurons using deep brain stimulation, pharmacotherapy or optogenetics.SIGNIFICANCE STATEMENTIn Parkinson’s disease, alleviating locomotor deficits is a challenge. Clinicians are exploring deep brain stimulation of the Mesencephalic Locomotor Region, a brainstem region controlling locomotion, but results are mixed. However, the best target in this region in Parkinson’s disease remains unknown. Indeed, this region which comprises the pedunculopontine and cuneiform nuclei, contains different cell types with opposing effects on locomotor output. Here, using a mouse model where midbrain dopaminergic cells were damaged by a neurotoxin, we demonstrate that optogenetic activation of glutamatergic neurons in the cuneiform nucleus increases locomotion, controls speed, and evokes limb movements similar to those observed during spontaneous locomotion in intact animals. Our study identifies a potentially clinically relevant target to improve locomotor function in Parkinson’s disease.

scholarly journals A Case of Parkinson’s Disease with No Lewy Body Pathology due to a Homozygous Exon Deletion in Parkin

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Krisztina Kunszt Johansen ◽  
Sverre Helge Torp ◽  
Matthew J. Farrer ◽  
Emil K. Gustavsson ◽  
Jan O. Aasly
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Diagnostic Criteria ◽  
Lewy Body ◽  
Lewy Bodies ◽  
Neuronal Loss ◽  
Homozygous Deletion ◽  
Substantia Nigra Pars Compacta ◽  
Lewy Body Pathology ◽  
Deep Brain

Parkinson’s disease (PD) is a clinical diagnosis based on the presence of cardinal motor signs, good response to levodopa, and no other explanations of the syndrome. Earlier diagnostic criteria required autopsy for a definite diagnosis based on neuronal loss in the substantia nigra pars compacta (SNpc) and the presence of Lewy bodies and neurites. Here, we present a patient who developed parkinsonism around the age of 20, with an excellent response to levodopa who, at age 65, received bilateral STN deep brain stimulation (DBS). The patient died at age 79. The autopsy showed severe neuronal loss in the SN without any Lewy bodies in the brainstem or in the hemispheres. Genetic screening revealed a homozygous deletion of exon 3-4 in the Parkin gene. In this case report we discuss earlier described pathological findings in Parkin cases without Lewy body pathology, the current diagnostic criteria for PD, and their clinical relevance.

scholarly journals Neural substrates and potential treatments for levodopa-induced dyskinesias in Parkinson’s disease

2016 ◽  
Vol 27 (7) ◽  
pp. 729-738 ◽  
Author(s):  
Joseph R. Phillips ◽  
Abeer M. Eissa ◽  
Doaa H. Hewedi ◽  
Marjan Jahanshahi ◽  
Mohamed El-Gamal ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neuronal Loss ◽  
Neural Substrates ◽  
Substantia Nigra Pars Compacta ◽  
Motor Disorder ◽  
Cognitive Correlates ◽  
Downstream Effects ◽  
Gradual Loss ◽  
Dopaminergic Neuronal Loss

AbstractParkinson’s disease (PD) is primarily a motor disorder that involves the gradual loss of motor function. Symptoms are observed initially in the extremities, such as hands and arms, while advanced stages of the disease can effect blinking, swallowing, speaking, and breathing. PD is a neurodegenerative disease, with dopaminergic neuronal loss occurring in the substantia nigra pars compacta, thus disrupting basal ganglia functions. This leads to downstream effects on other neurotransmitter systems such as glutamate, γ-aminobutyric acid, and serotonin. To date, one of the main treatments for PD is levodopa. While it is generally very effective, prolonged treatments lead to levodopa-induced dyskinesia (LID). LID encompasses a family of symptoms ranging from uncontrolled repetitive movements to sustained muscle contractions. In many cases, the symptoms of LID can cause more grief than PD itself. The purpose of this review is to discuss the possible clinical features, cognitive correlates, neural substrates, as well as potential psychopharmacological and surgical (including nondopaminergic and deep brain stimulation) treatments of LID.

scholarly journals MicroRNAs: Game Changers in the Regulation of α-Synuclein in Parkinson’s Disease

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Liang Zhao ◽  
Zhiqin Wang
Keyword(s):  
Gene Expression ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Neurodegenerative Disorder ◽  
Noncoding Rnas ◽  
Lewy Bodies ◽  
Neuronal Loss ◽  
Substantia Nigra Pars Compacta ◽  
Common Neurodegenerative Disorder

Parkinson’s disease (PD) is the second most common neurodegenerative disorder. Its neuropathological hallmarks include neuronal loss in the substantia nigra pars compacta (SNpc) and the presence of Lewy bodies containing aggregates of α-synuclein (α-syn). An imbalance between the rates of α-syn synthesis, aggregation, and clearance can result in abnormal α-syn levels and contribute to the pathogenesis of PD. MicroRNAs (miRNAs) are endogenous single-stranded noncoding RNAs (∼22 nucleotides) that have recently emerged as key posttranscriptional regulators of gene expression. In this review, we summarize the functions of miRNAs that directly target α-syn. We also review miRNAs that indirectly impact α-syn levels or toxicity through different pathways, including those involved in the clearance of α-syn and neuroinflammation.

scholarly journals Dual Roles of Microglia in the Basal Ganglia in Parkinson’s Disease

2021 ◽  
Vol 22 (8) ◽  
pp. 3907
Author(s):  
Mohammed E. Choudhury ◽  
Yuka Kigami ◽  
Junya Tanaka
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Substantia Nigra ◽  
Neuronal Degeneration ◽  
Neuronal Loss ◽  
Therapeutic Interventions ◽  
Substantia Nigra Pars Compacta ◽  
Synapse Elimination ◽  
Dual Roles

With the increasing age of the population, the incidence of Parkinson’s disease (PD) has increased exponentially. The development of novel therapeutic interventions requires an understanding of the involvement of senescent brain cells in the pathogenesis of PD. In this review, we highlight the roles played by microglia in the basal ganglia in the pathophysiological processes of PD. In PD, dopaminergic (DAergic) neuronal degeneration in the substantia nigra pars compacta (SNc) activates the microglia, which then promote DAergic neuronal degeneration by releasing potentially neurotoxic factors, including nitric oxide, cytokines, and reactive oxygen species. On the other hand, microglia are also activated in the basal ganglia outputs (the substantia nigra pars reticulata and the globus pallidus) in response to excess glutamate released from hyperactive subthalamic nuclei-derived synapses. The activated microglia then eliminate the hyperactive glutamatergic synapses. Synapse elimination may be the mechanism underlying the compensation that masks the appearance of PD symptoms despite substantial DAergic neuronal loss. Microglial senescence may correlate with their enhanced neurotoxicity in the SNc and the reduced compensatory actions in the basal ganglia outputs. The dual roles of microglia in different basal ganglia regions make it difficult to develop interventions targeting microglia for PD treatment.

scholarly journals The Impact of SNCA Variations and Its Product Alpha-Synuclein on Non-Motor Features of Parkinson’s Disease

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 804
Author(s):  
Luca Magistrelli ◽  
Elena Contaldi ◽  
Cristoforo Comi
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Decline ◽  
Neuronal Degeneration ◽  
Lewy Bodies ◽  
Neuronal Loss ◽  
Alpha Synuclein ◽  
Substantia Nigra Pars Compacta ◽  
Main Component ◽  
The Impact

Parkinson’s disease (PD) is a common and progressive neurodegenerative disease, caused by the loss of dopaminergic neurons in the substantia nigra pars compacta in the midbrain, which is clinically characterized by a constellation of motor and non-motor manifestations. The latter include hyposmia, constipation, depression, pain and, in later stages, cognitive decline and dysautonomia. The main pathological features of PD are neuronal loss and consequent accumulation of Lewy bodies (LB) in the surviving neurons. Alpha-synuclein (α-syn) is the main component of LB, and α-syn aggregation and accumulation perpetuate neuronal degeneration. Mutations in the α-syn gene (SNCA) were the first genetic cause of PD to be identified. Generally, patients carrying SNCA mutations present early-onset parkinsonism with severe and early non-motor symptoms, including cognitive decline. Several SNCA polymorphisms were also identified, and some of them showed association with non-motor manifestations. The functional role of these polymorphisms is only partially understood. In this review we explore the contribution of SNCA and its product, α-syn, in predisposing to the non-motor manifestations of PD.

scholarly journals Colonic Dopaminergic Neurons Changed Reversely With Those in the Midbrain via Gut Microbiota-Mediated Autophagy in a Chronic Parkinson’s Disease Mice Model

2021 ◽  
Vol 13 ◽  
Author(s):  
Xin Liu ◽  
Zhong-Rui Du ◽  
Xiong Wang ◽  
Kar-Him Luk ◽  
Cheuk-Hin Chan ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Gut Microbiota ◽  
Dopaminergic Neurons ◽  
Short Chain Fatty Acids ◽  
Substantia Nigra Pars Compacta ◽  
Mice Model ◽  
Mptp Injection ◽  
Locomotor Deficits

The role of gut-brain axis in the pathogenesis of Parkinson’s disease (PD) have become a research hotspot, appropriate animal model to study gut-brain axis in PD is yet to be confirmed. Our study employed a classical PD mice model achieved by chronic MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) injection to study concurrent changes of dopaminergic neurons in the midbrain and the colon of mice. Our results showed such a PD model exhibited apparent locomotor deficits but not gastrointestinal dysfunction. Tyrosine hydroxylase expressions and dopamine content reduced greatly in the substantia nigra pars compacta (SNpc) or striatum, but increased in the colon of PD mice. Mechanism investigation indicated autophagy activity and apoptosis were stimulated in the SNpc, but inhibited in the colon of PD mice. Interplay of gut microbiota (GM) and autophagy in response to chronic MPTP injection led to GM dysbiosis and defective autophagy in mice colon. Meanwhile, fecal short chain fatty acids (SCFAs), acetate and propionate in particular, declined greatly in PD mice, which could be attributed to the decreased bacteria abundance of phylum Bacteroidetes, but increased abundance of phylum Firmicutes. GM dysbiosis derived fecal SCFAs might be one of the mediators of downregulated autophagy in the colon of PD mice. In conclusion, colonic dopaminergic neurons changed in the opposition direction with those in the midbrain via GM dysbiosis-mediated autophagy inhibition followed by suppressed apoptosis in response to chronic MPTP injection. Such a chronic PD mice model might not be an ideal model to study role of gut-brain axis in PD progression.

scholarly journals Modulation of beta bursts in subthalamic sensorimotor circuits predicts improvement in bradykinesia

Brain ◽  
2020 ◽  
Author(s):  
Yasmine M Kehnemouyi ◽  
Kevin B Wilkins ◽  
Chioma M Anidi ◽  
Ross W Anderson ◽  
Muhammad Furqan Afzal ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Deep Brain Stimulation ◽  
Subthalamic Nucleus ◽  
Brain Stimulation ◽  
Movement Velocity ◽  
Sensorimotor Region ◽  
Beta Power ◽  
Freely Moving ◽  
Deep Brain

Abstract No biomarker of Parkinson’s disease exists that allows clinicians to adjust chronic therapy, either medication or deep brain stimulation, with real-time feedback. Consequently, clinicians rely on time-intensive, empirical, and subjective clinical assessments of motor behaviour and adverse events to adjust therapies. Accumulating evidence suggests that hypokinetic aspects of Parkinson’s disease and their improvement with therapy are related to pathological neural activity in the beta band (beta oscillopathy) in the subthalamic nucleus. Additionally, effectiveness of deep brain stimulation may depend on modulation of the dorsolateral sensorimotor region of the subthalamic nucleus, which is the primary site of this beta oscillopathy. Despite the feasibility of utilizing this information to provide integrated, biomarker-driven precise deep brain stimulation, these measures have not been brought together in awake freely moving individuals. We sought to directly test whether stimulation-related improvements in bradykinesia were contingent on reduction of beta power and burst durations, and/or the volume of the sensorimotor subthalamic nucleus that was modulated. We recorded synchronized local field potentials and kinematic data in 16 subthalamic nuclei of individuals with Parkinson’s disease chronically implanted with neurostimulators during a repetitive wrist-flexion extension task, while administering randomized different intensities of high frequency stimulation. Increased intensities of deep brain stimulation improved movement velocity and were associated with an intensity-dependent reduction in beta power and mean burst duration, measured during movement. The degree of reduction in this beta oscillopathy was associated with the improvement in movement velocity. Moreover, the reduction in beta power and beta burst durations was dependent on the theoretical degree of tissue modulated in the sensorimotor region of the subthalamic nucleus. Finally, the degree of attenuation of both beta power and beta burst durations, together with the degree of overlap of stimulation with the sensorimotor subthalamic nucleus significantly explained the stimulation-related improvement in movement velocity. The above results provide direct evidence that subthalamic nucleus deep brain stimulation-related improvements in bradykinesia are related to the reduction in beta oscillopathy within the sensorimotor region. With the advent of sensing neurostimulators, this beta oscillopathy combined with lead location could be used as a marker for real-time feedback to adjust clinical settings or to drive closed-loop deep brain stimulation in freely moving individuals with Parkinson’s disease.

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