scholarly journals Mechanistic Insights Expatiating the Redox-Active-Metal-Mediated Neuronal Degeneration in Parkinson’s Disease

2022 ◽  
Vol 23 (2) ◽  
pp. 678
Author(s):  
Tapan Behl ◽  
Piyush Madaan ◽  
Aayush Sehgal ◽  
Sukhbir Singh ◽  
Md Khalid Anwer ◽  
...  

Parkinson’s disease (PD) is a complicated and incapacitating neurodegenerative malady that emanates following the dopaminergic (DArgic) nerve cell deprivation in the substantia nigra pars compacta (SN-PC). The etiopathogenesis of PD is still abstruse. Howbeit, PD is hypothesized to be precipitated by an amalgamation of genetic mutations and exposure to environmental toxins. The aggregation of α-synucelin within the Lewy bodies (LBs), escalated oxidative stress (OS), autophagy-lysosome system impairment, ubiquitin-proteasome system (UPS) impairment, mitochondrial abnormality, programmed cell death, and neuroinflammation are regarded as imperative events that actively participate in PD pathogenesis. The central nervous system (CNS) relies heavily on redox-active metals, particularly iron (Fe) and copper (Cu), in order to modulate pivotal operations, for instance, myelin generation, synthesis of neurotransmitters, synaptic signaling, and conveyance of oxygen (O2). The duo, namely, Fe and Cu, following their inordinate exposure, are viable of permeating across the blood–brain barrier (BBB) and moving inside the brain, thereby culminating in the escalated OS (through a reactive oxygen species (ROS)-reliant pathway), α-synuclein aggregation within the LBs, and lipid peroxidation, which consequently results in the destruction of DArgic nerve cells and facilitates PD emanation. This review delineates the metabolism of Fe and Cu in the CNS, their role and disrupted balance in PD. An in-depth investigation was carried out by utilizing the existing publications obtained from prestigious medical databases employing particular keywords mentioned in the current paper. Moreover, we also focus on decoding the role of metal complexes and chelators in PD treatment. Conclusively, metal chelators hold the aptitude to elicit the scavenging of mobile/fluctuating metal ions, which in turn culminates in the suppression of ROS generation, and thereby prelude the evolution of PD.

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 283
Author(s):  
Daniel Aghaie Madsen ◽  
Sissel Ida Schmidt ◽  
Morten Blaabjerg ◽  
Morten Meyer

Parkin and α-synuclein are two key proteins involved in the pathophysiology of Parkinson’s disease (PD). Neurotoxic alterations of α-synuclein that lead to the formation of toxic oligomers and fibrils contribute to PD through synaptic dysfunction, mitochondrial impairment, defective endoplasmic reticulum and Golgi function, and nuclear dysfunction. In half of the cases, the recessively inherited early-onset PD is caused by loss of function mutations in the PARK2 gene that encodes the E3-ubiquitin ligase, parkin. Parkin is involved in the clearance of misfolded and aggregated proteins by the ubiquitin-proteasome system and regulates mitophagy and mitochondrial biogenesis. PARK2-related PD is generally thought not to be associated with Lewy body formation although it is a neuropathological hallmark of PD. In this review article, we provide an overview of post-mortem neuropathological examinations of PARK2 patients and present the current knowledge of a functional interaction between parkin and α-synuclein in the regulation of protein aggregates including Lewy bodies. Furthermore, we describe prevailing hypotheses about the formation of intracellular micro-aggregates (synuclein inclusions) that might be more likely than Lewy bodies to occur in PARK2-related PD. This information may inform future studies aiming to unveil primary signaling processes involved in PD and related neurodegenerative disorders.


2020 ◽  
pp. 107385842094221
Author(s):  
Shubhangini Tiwari ◽  
Sarika Singh

Parkinson’s disease (PD) pathology involves degeneration of nigrostriatal pathway, postulating symptoms associated with age, environment, and genetic anomalies, including nonlinear disease progression. Hallmark characteristics of PD include dopaminergic neuronal degeneration and death, which may also be exhibited by other neurological diseases, making the diagnosis of the disease intricate at early stage. Such obscure diagnosis of the disease, limited symptomatic improvements with available therapeutics, and their inability to modify the disease status instigate us to appraise the past research and formulate the colligating comprehensive insights. This review is accentuating on the role of nitric oxide, endoplasmic reticulum stress, and their association with the ubiquitin proteasome system (UPS) during PD pathology involving focus on ubiquitin ligases due to their regulatory functions. Meticulous understanding of these major disease-related pathological events and their functional alliance may render novel dimensions for better understanding of disease etiology, related mechanisms, as well as direction toward witnessing of new therapeutic targets for the management of Parkinson’s patients.


Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1508
Author(s):  
Anna Picca ◽  
Flora Guerra ◽  
Riccardo Calvani ◽  
Roberta Romano ◽  
Hélio José Coelho-Júnior ◽  
...  

Parkinson’s Disease (PD) is a highly prevalent neurodegenerative disease among older adults. PD neuropathology is marked by the progressive loss of the dopaminergic neurons of the substantia nigra pars compacta and the widespread accumulation of misfolded intracellular α-synuclein (α-syn). Genetic mutations and post-translational modifications, such as α-syn phosphorylation, have been identified among the multiple factors supporting α-syn accrual during PD. A decline in the clearance capacity of the ubiquitin-proteasome and the autophagy-lysosomal systems, together with mitochondrial dysfunction, have been indicated as major pathophysiological mechanisms of PD neurodegeneration. The accrual of misfolded α-syn aggregates into soluble oligomers, and the generation of insoluble fibrils composing the core of intraneuronal Lewy bodies and Lewy neurites observed during PD neurodegeneration, are ignited by the overproduction of reactive oxygen species (ROS). The ROS activate the α-syn aggregation cascade and, together with the Lewy bodies, promote neurodegeneration. However, the molecular pathways underlying the dynamic evolution of PD remain undeciphered. These gaps in knowledge, together with the clinical heterogeneity of PD, have hampered the identification of the biomarkers that may be used to assist in diagnosis, treatment monitoring, and prognostication. Herein, we illustrate the main pathways involved in PD pathogenesis and discuss their possible exploitation for biomarker discovery.


2017 ◽  
Vol 158 (17) ◽  
pp. 643-652 ◽  
Author(s):  
János Bencze ◽  
Viktória Simon ◽  
Erika Bereczki ◽  
Réka Majer ◽  
Gréta Varkoly ◽  
...  

Abstract: Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia. The accurate diagnosis is often possible only by neuropathological examination. The morphologic hallmarks are the presence of α-synuclein-rich Lewy bodies and Lewy neurites, identical to those seen in Parkinson’s disease (PD) and Parkinson’s disease dementia (PDD). Neurotransmitter deficits, synaptic and ubiquitin-proteasome system (UPS) dysfunction play major role in the pathomechanism. Characteristic symptoms are cognitive fluctuation, parkinsonism and visual hallucinations. Due to the often atypical clinical presentation novel imaging techniques and biomarkers could help the early diagnosis. Although curative treatment is not available, therapies can improve quality of life. Clinicopathological studies are important in exploring pathomechanisms, ensuring accurate diagnosis and identifying therapeutic targets. Orv Hetil. 2017; 158(17): 643–652.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Juan Antonio Castillo-Gonzalez ◽  
Maria De Jesus Loera-Arias ◽  
Odila Saucedo-Cardenas ◽  
Roberto Montes-de-Oca-Luna ◽  
Aracely Garcia-Garcia ◽  
...  

Parkinson’s disease is the second most important neurodegenerative disorder worldwide. It is characterized by the presence of Lewy bodies, which are mainly composed ofα-synuclein and ubiquitin-bound proteins. Both the ubiquitin proteasome system (UPS) and autophagy-lysosomal pathway (ALS) are altered in Parkinson’s disease, leading to aggregation of proteins, particularlyα-synuclein. Interestingly, it has been observed that copper promotes the protein aggregation process. Additionally, phosphorylation ofα-synuclein along with copper also affects the protein aggregation process. The interrelation amongα-synuclein phosphorylation and its capability to interact with copper, with the subsequent disruption of the protein degradation systems in the neurodegenerative process of Parkinson’s disease, will be analyzed in detail in this review.


Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 804
Author(s):  
Luca Magistrelli ◽  
Elena Contaldi ◽  
Cristoforo Comi

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.


2016 ◽  
Vol 10 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Mohsin H.K. Roshan ◽  
Amos Tambo ◽  
Nikolai P. Pace

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.


2021 ◽  
Vol 44 (1) ◽  
pp. 87-108
Author(s):  
Gabriel E. Vázquez-Vélez ◽  
Huda Y. Zoghbi

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Dinendra L. Abeyawardhane ◽  
Heather R. Lucas

The etiology of Parkinson’s disease (PD) is linked with cellular inclusions in the substantia nigra pars compacta region of the brain that are enriched in the misfolded presynaptic protein α-synuclein (αS) and death of the dopaminergic neurons. Brain iron homeostasis governs both neurotransmission and neurodegeneration; hence, the role of iron in PD progression and neuronal health is apparent. Elevated iron deposits become prevalent in the cerebral region upon aging and even more so in the PD brain. Structural as well as oxidative modifications can result from coordination of αS with redox active iron, which could have functional and/or pathological implications. In this review, we will discuss iron-mediated αS aggregation, alterations in iron metabolism, and the role of the iron-dopamine couple. Moreover, iron interactions with N-terminally acetylated αS, the physiologically relevant form of the human protein, will be addressed to shed light on the current understanding of protein dynamics and the physiological environment in the disease state. Oxidative pathways and biochemical alterations resulting from aberrant iron-induced chemistry are the principal focus of this review in order to highlight the plethora of research that has uncovered this emerging dichotomy of iron playing both functional and disruptive roles in PD pathology.


2019 ◽  
Vol 121 (5) ◽  
pp. 1856-1864 ◽  
Author(s):  
Cecilia Bove ◽  
R. Alberto Travagli

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.


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