scholarly journals Neurophysiology of the brain stem in Parkinson’s disease

2019 ◽  
Vol 121 (5) ◽  
pp. 1856-1864 ◽  
Author(s):  
Cecilia Bove ◽  
R. Alberto Travagli
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Neuronal Degeneration ◽  
Alternative Hypothesis ◽  
Large Body ◽  
Substantia Nigra Pars Compacta ◽  
Clinical Feature ◽  
Motor Nucleus ◽  
Gi Symptoms

Parkinson’s disease (PD) is predominantly idiopathic in origin, and a large body of evidence indicates that gastrointestinal (GI) dysfunctions are a significant comorbid clinical feature; these dysfunctions include dysphagia, nausea, delayed gastric emptying, and severe constipation, all of which occur commonly before the onset of the well-known motor symptoms of PD. Based on a distinct distribution pattern of Lewy bodies (LB) in the enteric nervous system (ENS) and in the preganglionic neurons of the dorsal motor nucleus of the vagus (DMV), and together with the early onset of GI symptoms, it was suggested that idiopathic PD begins in the ENS and spreads to the central nervous system (CNS), reaching the DMV and the substantia nigra pars compacta (SNpc). These two areas are connected by a recently discovered monosynaptic nigro-vagal pathway, which is dysfunctional in rodent models of PD. An alternative hypothesis downplays the role of LB transport through the vagus nerve and proposes that PD pathology is governed by regional or cell-restricted factors as the leading cause of nigral neuronal degeneration. The purpose of this brief review is to summarize the neuronal electrophysiological findings in the SNpc and DMV in PD.

scholarly journals What Is the Evidence that Parkinson’s Disease Is a Prion Disorder, Which Originates in the Gut?

2018 ◽  
Vol 19 (11) ◽  
pp. 3573 ◽  
Author(s):  
Małgorzata Kujawska ◽  
Jadwiga Jodynis-Liebert
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Neurodegenerative Disorder ◽  
Human Subjects ◽  
Gastrointestinal Symptoms ◽  
Convincing Evidence ◽  
Substantia Nigra Pars Compacta ◽  
Motor Nucleus ◽  
The Brain

Parkinson’s disease (PD) is a neurodegenerative disorder resulting from degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). PD is characterized by motor dysfunctions as well as gastrointestinal symptoms and mental impairment. The pathological hallmark of PD is an accumulation of misfolded α-synuclein aggregates within the brain. The etiology of PD and related synucleinopathy is poorly understood, but recently, the hypothesis that α-synuclein pathology spreads in a prion-like fashion originating in the gut has gained much scientific attention. A crucial clue was the appearance of constipation before the onset of motor symptoms, gut dysbiosis and synucleinopathy in PD patients. Another line of evidence, demonstrating accumulation of α-synuclein within the peripheral autonomic nervous system (PANS), including the enteric nervous system (ENS), and the dorsal motor nucleus of the vagus (DMV) support the concept that α-synuclein can spread from the ENS to the brain by the vagus nerve. The decreased risk of PD following truncal vagotomy supports this. The convincing evidence of the prion-like behavior of α-synuclein came from postmortem observations that pathological α-synuclein inclusions appeared in healthy grafted neurons. In this review, we summarize the available data from human subjects’ research and animal experiments, which seem to be the most suggestive for explaining the hypotheses.

scholarly journals Hypothesis of Ascension in Idiopathic Parkinson’s Disease

2017 ◽  
Vol 01 (01) ◽  
pp. E28-E35
Author(s):  
L. Klingelhoefer ◽  
H. Reichmann
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Olfactory Bulb ◽  
Substantia Nigra Pars Compacta ◽  
Motor Nucleus ◽  
Motor Symptoms ◽  
Idiopathic Parkinson’S Disease ◽  
Idiopathic Parkinson's Disease ◽  
Non Motor Symptoms

AbstractDifferent clinical stages are observed in idiopathic Parkinson’s disease (PD). Non-motor symptoms define in particular the prodromal period of PD whereas primary motor symptoms such as bradykinesia with rigidity, resting tremor or postural instability are mandatory for the diagnosis of PD. Important non-motor symptoms are olfactory dysfunction, constipation, depression and sleep disturbances. Corresponding to the clinical course of PD, the Braak staging system postulates that the neuropathological process of PD starts in the enteric nervous system (ENS) of the gut and in the olfactory bulb. From there, Parkinson pathology spreads by transsynaptic cell-to-cell transfer via the sympathetic and parasympathetic nervous system in a rostrocranial direction. If the central nervous system is reached, typical neuropathological changes of PD with selective degeneration of dopaminergic neurons of the Substantia nigra pars compacta, the formation of Lewy bodies, reactive gliosis and progressive central neurodegeneration appear. Evidence of clinical, pathological and animal studies supporting these hypotheses are summarised in this review article. α-synuclein as PD-specific pathology was found in the olfactory bulb, the ENS, the submandibular gland, the intermediolateral nucleus of the spinal cord and the dorsal motor nucleus of the vagus nerve. In an animal model, in which mice are treated with the pesticide rotenone chronically and intragastrically, we could almost completely reproduce the typical pathological and clinical features of PD as well as their development in a chronological and regional sequence.

scholarly journals Native α-Synuclein, 3-Nitrotyrosine Proteins, and Patterns of Nitro-α-Synuclein-Immunoreactive Inclusions in Saliva and Submandibulary Gland in Parkinson’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 715
Author(s):  
Emilio Fernández-Espejo ◽  
Fernando Rodríguez de Fonseca ◽  
Juan Suárez ◽  
Eduardo Tolosa ◽  
Dolores Vilas ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Clinical Features ◽  
Clinical Feature ◽  
Similar Concentration ◽  
Duct Cells ◽  
Nitrative Stress ◽  
Salivary Concentration

Background. Salivary α-synuclein (aSyn) and its nitrated form, or 3-nitrotyrosine-α-synuclein (3-NT-αSyn), hold promise as biomarkers for idiopathic Parkinson’s disease (IPD). Nitrative stress that is characterized by an excess of 3-nitrotyrosine proteins (3-NT-proteins) has been proposed as a pathogenic mechanism in IPD. The objective is to study the pathological role of native αSyn, 3-NT-αSyn, and 3-NT-proteins in the saliva and submandibulary glands of patients with IPD. Methods. The salivary and serum αSyn and 3-NT-proteins concentration is evaluated with ELISA in patients and controls. Correlations of αSyn and 3-NT-proteins content with clinical features of the disease are examined. Immunohistochemical 3-NT-αSyn expression in submandibulary gland sections is analyzed. Results. (a) Salivary concentration and saliva/serum ratios of native αSyn and 3-NT-proteins are similar in patients and controls; (b) salivary αSyn and 3-NT-proteins do not correlate with any clinical feature; and (c) three patterns of 3-NT-αSyn-positive inclusions are observed on histological sections: rounded “Lewy-type” aggregates of 10–25 µm in diameter, coarse deposits with varied morphology, and spheroid inclusions or bodies of 3–5 µm in diameter. “Lewy-type” and coarse inclusions are observed in the interlobular connective tissue of the gland, and small-sized bodies are located within the cytoplasm of duct cells. “Lewy-type” inclusions are only observed in patients, and the remaining patterns of inclusions are observed in both the patients and controls. Conclusions. The patients’ saliva presents a similar concentration of native αSyn and 3-nitrotyrosine-proteins than that of the controls, and no correlations with clinical features are found. These findings preclude the utility of native αSyn in the saliva as a biomarker, and they indicate the absence of nitrative stress in the saliva and serum of patients. As regards nitrated αSyn, “Lewy-type” inclusions expressing 3-NT-αSyn are observed in the patients, not the controls—a novel finding that suggests that a biopsy of the submandibulary gland, if proven safe, could be a useful technique for diagnosing IPD. Finally, to our knowledge, this is also the first description of 3-NT-αSyn-immunoreactive intracytoplasmic bodies in cells that are located outside the nervous system. These intracytoplasmic bodies are present in duct cells of submandibulary gland sections from all subjects regardless of their pathology, and they can represent an aging or involutional change. Further immunostaining studies with different antibodies and larger samples are needed to validate the data.

scholarly journals miR-335 Targets LRRK2 and Mitigates Inflammation in Parkinson’s Disease

2021 ◽  
Vol 9 ◽  
Author(s):  
Sara R. Oliveira ◽  
Pedro A. Dionísio ◽  
Maria M. Gaspar ◽  
Leonor Correia Guedes ◽  
Miguel Coelho ◽  
...  
Keyword(s):  
Gene Expression ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neuronal Degeneration ◽  
Experimental Models ◽  
Substantia Nigra Pars Compacta ◽  
Microglia Cell ◽  
Chronic Neuroinflammation ◽  
Proinflammatory Gene ◽  
Proinflammatory Gene Expression

Parkinson’s disease (PD) is mainly driven by dopaminergic neuronal degeneration in the substantia nigra pars compacta accompanied by chronic neuroinflammation. Despite being mainly sporadic, approximately 10% of all cases are defined as heritable forms of PD, with mutations in the leucine-rich repeat kinase (LRRK2) gene being the most frequent known cause of familial PD. MicroRNAs (miRNAs or miRs), including miR-335, are frequently deregulated in neurodegenerative diseases, such as PD. Here, we aimed to dissect the protective role of miR-335 during inflammation and/or neurodegenerative events in experimental models of PD. Our results showed that miR-335 is significantly downregulated in different PD-mimicking conditions, including BV2 microglia cells stimulated with lipopolysaccharide (LPS) and/or overexpressing wild-type LRRK2. Importantly, these results were confirmed in serum of mice injected with 1-methyl-1-4-phenyl-1,2,3,6-tetrahydripyridine hydrochloride (MPTP), and further validated in patients with idiopathic PD (iPD) and those harboring mutations in LRRK2 (LRRK2-PD), thus corroborating potential clinical relevance. Mechanistically, miR-335 directly targeted LRRK2 mRNA. In the BV2 and N9 microglia cell lines, miR-335 strongly counteracted LPS-induced proinflammatory gene expression, and downregulated receptor interacting protein 1 (RIP1) and RIP3, two important players of necroptotic and inflammatory signaling pathways. Further, miR-335 inhibited LPS-mediated ERK1/2 activation. LRRK2-Wt-induced proinflammatory gene expression was also significantly reduced by miR-335 overexpression. Finally, in SH-SY5Y neuroblastoma cells, miR-335 decreased the expression of pro-inflammatory genes triggered by α-synuclein. In conclusion, we revealed novel roles for miR-335 in both microglia and neuronal cells that strongly halt the effects of classical inflammatory stimuli or LRRK2-Wt overexpression, thus attenuating chronic neuroinflammation.

scholarly journals Could Small Heat Shock Protein HSP27 Be a First-Line Target for Preventing Protein Aggregation in Parkinson’s Disease?

2021 ◽  
Vol 22 (6) ◽  
pp. 3038
Author(s):  
Javier Navarro-Zaragoza ◽  
Lorena Cuenca-Bermejo ◽  
Pilar Almela ◽  
María-Luisa Laorden ◽  
María-Trinidad Herrero
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Heat Shock ◽  
Stress Proteins ◽  
Small Heat Shock Protein ◽  
Substantia Nigra Pars Compacta ◽  
Motor Symptoms ◽  
Dopaminergic Drugs ◽  
Non Motor Symptoms

Small heat shock proteins (HSPs), such as HSP27, are ubiquitously expressed molecular chaperones and are essential for cellular homeostasis. The major functions of HSP27 include chaperoning misfolded or unfolded polypeptides and protecting cells from toxic stress. Dysregulation of stress proteins is associated with many human diseases including neurodegenerative diseases, such as Parkinson’s disease (PD). PD is characterized by the presence of aggregates of α-synuclein in the central and peripheral nervous system, which induces the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and in the autonomic nervous system. Autonomic dysfunction is an important non-motor phenotype of PD, which includes cardiovascular dysregulation, among others. Nowadays, the therapies for PD focus on dopamine (DA) replacement. However, certain non-motor symptoms with a great impact on quality of life do not respond to dopaminergic drugs; therefore, the development and testing of new treatments for non-motor symptoms of PD remain a priority. Since small HSP27 was shown to prevent α-synuclein aggregation and cytotoxicity, this protein might constitute a suitable target to prevent or delay the motor and non-motor symptoms of PD. In the first part of our review, we focus on the cardiovascular dysregulation observed in PD patients. In the second part, we present data on the possible role of HSP27 in preventing the accumulation of amyloid fibrils and aggregated forms of α-synuclein. We also include our own studies, highlighting the possible protective cardiac effects induced by L-DOPA treatment through the enhancement of HSP27 levels and activity.

scholarly journals Bidirectional gut-to-brain and brain-to-gut propagation of synucleinopathy in non-human primates

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1462-1475 ◽  
Author(s):  
Marie-Laure Arotcarena ◽  
Sandra Dovero ◽  
Alice Prigent ◽  
Mathieu Bourdenx ◽  
Sandrine Camus ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Vagus Nerve ◽  
Enteric Nervous System ◽  
General Circulation ◽  
Motor Nucleus ◽  
Long Distance ◽  
Primate Model ◽  
Systemic Mechanism

Abstract In Parkinson’s disease, synucleinopathy is hypothesized to spread from the enteric nervous system, via the vagus nerve, to the CNS. Here, we compare, in baboon monkeys, the pathological consequences of either intrastriatal or enteric injection of α-synuclein-containing Lewy body extracts from patients with Parkinson’s disease. This study shows that patient-derived α-synuclein aggregates are able to induce nigrostriatal lesions and enteric nervous system pathology after either enteric or striatal injection in a non-human primate model. This finding suggests that the progression of α-synuclein pathology might be either caudo-rostral or rostro-caudal, varying between patients and disease subtypes. In addition, we report that α-synuclein pathological lesions were not found in the vagal nerve in our experimental setting. This study does not support the hypothesis of a transmission of α-synuclein pathology through the vagus nerve and the dorsal motor nucleus of the vagus. Instead, our results suggest a possible systemic mechanism in which the general circulation would act as a route for long-distance bidirectional transmission of endogenous α-synuclein between the enteric and the central nervous systems. Taken together, our study provides invaluable primate data exploring the role of the gut-brain axis in the initiation and propagation of Parkinson’s disease pathology and should open the door to the development and testing of new therapeutic approaches aimed at interfering with the development of sporadic Parkinson’s disease.

scholarly journals Propagated α-synucleinopathy recapitulates REM sleep behaviour disorder followed by parkinsonian phenotypes in mice

Brain ◽  
2020 ◽  
Vol 143 (11) ◽  
pp. 3374-3392
Author(s):  
Yan Shen ◽  
Wen-Bo Yu ◽  
Bo Shen ◽  
Hui Dong ◽  
Jue Zhao ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Animal Model ◽  
Mouse Model ◽  
Experimental Studies ◽  
Substantia Nigra Pars Compacta ◽  
Motor Nucleus ◽  
Behaviour Disorder ◽  
Tegmental Nucleus ◽  
Sleep Behaviour

Abstract Idiopathic rapid eye movement sleep behaviour disorder (RBD) is now recognized as an early manifestation of α-synucleinopathies. Increasing experimental studies demonstrate that manipulative lesion or inactivation of the neurons within the sublaterodorsal tegmental nucleus (also known as the subcoeruleus nucleus in humans) can induce RBD-like behaviours in animals. As current RBD animal models are not established on the basis of α-synucleinopathy, they do not represent the pathological substrate of idiopathic RBD and thus cannot model the phenoconversion to Parkinson’s disease. The purpose of this study was therefore to establish an α-synucleinopathy-based RBD animal model with the potential to convert to parkinsonian disorder. To this end, we first determined the functional neuroanatomical location of the sublaterodorsal tegmental nucleus in wild-type C57BL/6J mice and then validated its function by recapitulating RBD-like behaviours based on this determined nucleus. Next, we injected preformed α-synuclein fibrils into the sublaterodorsal tegmental nucleus and performed regular polysomnographic recordings and parkinsonian behavioural and histopathological studies in these mice. As a result, we recapitulated RBD-like behaviours in the mice and further showed that the α-synucleinopathy and neuron degeneration identified within the sublaterodorsal tegmental nucleus acted as the neuropathological substrates. Subsequent parkinsonian behavioural studies indicated that the α-synucleinopathy-based RBD mouse model were not stationary, but could further progress to display parkinsonian locomotor dysfunction, depression-like disorder, olfactory dysfunction and gastrointestinal dysmotility. Corresponding to that, we determined α-synuclein pathology in the substantia nigra pars compacta, olfactory bulb, enteral neuroplexus and dorsal motor nucleus of vagus nerve, which could underlie the parkinsonian manifestations in mice. In conclusion, we established a novel α-synucleinopathy-based RBD mouse model and further demonstrated the phenoconversion of RBD to Parkinson’s disease in this animal model.

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

2020 ◽  
Vol 21 (9) ◽  
pp. 3254 ◽  
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.

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.

Sign in / Sign up

Export Citation Format

Share Document