Mechanisms of protein toxicity in neurodegenerative diseases (original) (raw)
Related papers
Cells
Multiple neurodegenerative diseases (NDDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington’s disease (HD) are being suggested to have common cellular and molecular pathological mechanisms, characterized mainly by protein misfolding and aggregation. These large inclusions, most likely, represent an end stage of a molecular cascade; however, the soluble misfolded proteins, which take part in earlier steps of this cascade, are the more toxic players. These pathological proteins, which characterize each specific disease, lead to the selective vulnerability of different neurons, likely resulting from a combination of different intracellular mechanisms, including mitochondrial dysfunction, ER stress, proteasome inhibition, excitotoxicity, oxidative damage, defects in nucleocytoplasmic transport, defective axonal transport and neuroinflammation. Damage within these neurons is enhanced by damage from the nonneuronal cells, via i...
BMC neuroscience, 2015
Accumulation of protein aggregates is the leading cause of cellular dysfunction in neurodegenerative disorders. Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, Prion disease and motor disorders such as amyotrophic lateral sclerosis, present with a similar pattern of progressive neuronal death, nervous system deterioration and cognitive impairment. The common characteristic is an unusual misfolding of proteins which is believed to cause protein deposition and trigger degenerative signals in the neurons. A similar clinical presentation seen in many neurodegenerative disorders suggests the possibility of shared neuronal responses in different disorders. Despite the difference in core elements of deposits in each neurodegenerative disorder, the cascade of neuronal reactions such as activation of glycogen synthase kinase-3 beta, mitogen-activated protein kinases, cell cycle re-entry and oxidative stress leading to a progressive neurodegeneration are ...
Brain Pathology, 2010
Human neurodegenerative diseases with abnormal protein aggregates are associated with aberrant post-translational modifications, solubility, aggregation and fibril formation of selected proteins which cannot be degraded by cytosolic proteases, ubiquitin–protesome system and autophagy, and, therefore, accumulate in cells and extracellular compartments as residual debris. In addition to the accumulation of “primary” proteins, several other mechanisms are involved in the degenerative process and probably may explain crucial aspects such as the timing, selective cellular vulnerability and progression of the disease in particular individuals. One of these mechanisms is oxidative stress, which occurs in the vast majority of, if not all, degenerative diseases of the nervous system. The present review covers most of the protein targets that have been recognized as modified proteins mainly using bidimensional gel electrophoresis, Western blotting with oxidative and nitrosative markers, and identified by mass spectrometry in Alzheimer disease; certain tauopathies such as progressive supranuclear palsy, Pick disease, argyrophilic grain disease and frontotemporal lobar degeneration linked to mutations in tau protein, for example, FTLD-tau, Parkinson disease and related α-synucleinopathies; Huntington disease; and amyotrophic lateral sclerosis, together with related animal and cellular models. Vulnerable proteins can be mostly grouped in defined metabolic pathways covering glycolysis and energy metabolism, cytoskeletal, chaperoning, cellular stress responses, and members of the ubiquitin–proteasome system. Available information points to the fact that vital metabolic pathways are hampered by protein oxidative damage in several human degenerative diseases and that oxidative damage occurs at very early stages of the disease. Yet parallel functional studies are limited and further work is needed to document whether protein oxidation results in loss of activity and impaired performance. A better understanding of proteins susceptible to oxidation and nitration may serve to define damaged metabolic networks at early stages of disease and to advance therapeutic interventions to attenuate disease progression.
Misfolded proteins toxicity in motor neuron diseases
2015
Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome caused by various conditions such as infection and trauma. [1] During the last five decades, a better understanding of the epidemiology, pathophysiology, and pathogenesis of ARDS has led to new treatment strategies that improved survival rates significantly in patients with ARDS. However, the mortality of severe ARDS is still over 40.0%. [2] Early recognition of ARDS and optimized management are crucial for outcome improvement. hugE BurdEn of acutE rEsPIratory dIstrEss syndromE ARDS is a common disease with a high variation of incidence worldwide. Epidemiological studies of ARDS have revealed an incidence of 10.1 per 100,000 person-years in South America, 17.9/100,000 person-years in Europe, 34/100,000 person-years in Australia, and 78.9/100,000 person-years in the USA. [3-6] In intensive care units (ICUs), the incidence of ARDS is 7.1-12.5% in European countries. A global study conducted over fifty countries showed that 10.4% (95% confidence interval [
Emerging Developments in Targeting Proteotoxicity in Neurodegenerative Diseases
CNS Drugs
The most common neurodegenerative diseases are Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, frontotemporal lobar degeneration, and the motor neuron diseases, with AD affecting approximately 6% of people aged 65 years and older, and PD affecting approximately 1% of people aged over 60 years. Specific proteins are associated with these neurodegenerative diseases, as determined by both immunohistochemical studies on post-mortem tissue and genetic screening, where protein misfolding and aggregation are key hallmarks. Many of these proteins are shown to misfold and aggregate into soluble non-native oligomers and large insoluble protein deposits (fibrils and plaques), both of which may exert a toxic gain of function. Proteotoxicity has been examined intensively in cell culture and in in vivo models, and clinical trials of methods to attenuate proteotoxicity are relatively new. Therapies to enhance cellular protein quality control mechanisms such as upregulation of chaperones and clearance/degradation pathways, as well as immunotherapies against toxic protein conformations, are being actively pursued. In this article, we summarize the common pathophysiology of neurodegenerative disease, and review therapies in early-phase clinical trials that target the proteotoxic component of several neurodegenerative diseases.
Promoting the clearance of neurotoxic proteins in neurodegenerative disorders of ageing
Nature Reviews Drug Discovery
Neurodegenerative disorders of ageing (NDAs) like Alzheimer's disease, Parkinson's disease, frontotemporal dementia, Huntington's disease and amyotrophic lateral sclerosis represent a major socioeconomic challenge in view of their high prevalence yet poor treatment. They are often called proteinopathies in view of the presence of misfolded and aggregated proteins that lose their physiological roles and acquire neurotoxic properties. One reason underlying the accumulation and spread of oligomeric forms of neurotoxic proteins is insufficient clearance by the autophagic-lysosomal network. Several other clearance pathways are likewise compromised in NDAs: chaperone-mediated autophagy, the ubiquitin-proteasome system, extracellular clearance by proteases, and extrusion into the circulation via the blood-brain barrier and glymphatic system. The present article focuses on emerging mechanisms for enhancing neurotoxic protein clearance, a strategy that may curtail the onset and slow the progression of NDAs.
Protein aggregation and degradation mechanisms in neurodegenerative diseases
American Journal of Neurodegenerative Disease, 2013
Neurodegenerative diseases are characterized by selective neuronal vulnerability and neurodegeneration in specific brain regions. The pathogenesis of these disorders centrally involves abnormal accumulation and aggregation of specific proteins, which are deposited in intracellular inclusions or extracellular aggregates that are characteristic for each disease. Increasing evidence suggests that genetic mutations or environmental factors can instigate protein misfolding and aggregation in these diseases. Consequently, neurodegenerative diseases are often considered as conformational diseases. This idea is further supported by studies implicating that impairment of the protein quality control (PQC) and clearance systems, such as the ubiquitin-proteasome system and autophagosome-lysosome pathway, may lead to the abnormal accumulation of disease-specific proteins. This suggests that similar pathological mechanisms may underlie the pathogenesis of the different neurodegenerative disorders. Interestingly, several proteins that are known to associate with neurodegenerative diseases have been identified as important regulators of PQC and clearance systems. In this review, we summarize the central features of abnormal protein accumulation in different common neurodegenerative diseases and discuss some aspects of specific disease-associated proteins regulating the PQC and clearance mechanisms, such as ubiquilin-1.
Editorial: Protein misfolding, altered mechanisms and neurodegeneration
Frontiers in Molecular Neuroscience
Editorial on the Research Topic Protein misfolding, altered mechanisms and neurodegeneration Neurodegenerative diseases (NDs) like Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), Frontotemporal lobe degeneration (FTLD), Polyglutamine diseases such as Huntington's disease (HD), Spinocerebellar ataxias (SCAs) etc., are a group of debilitating disorders that affects millions of people worldwide and have no cure to-date. Despite the advancement in our understanding of molecular and genetic mechanisms underlying these NDs, only a limited symptom-based treatment options are available. As the life expectancy increases there is an increase in the number of ND patients, which will seriously challenge the availability of resources and will impact a nation's economy. There is an urgent need to develop an affordable healthcare system and find effective treatment options to provide better clinical regimens to cure these diseases. NDs affect neurons, neuronal connections associated with memory, cognition, thinking, strength, sensation, movements, learning, coordination , and other abilities. Although the causative factors of NDs varies from one to another and the differences in the disease symptoms could be many, these diseases share some common features. One of the common pathological hallmarks among the most NDs is aggregation or deposition of misfolded proteins. Compelling evidence from neuropathological, genetic, animal models studies, and other approaches have strongly supported the fact that accumulation of misfolded protein aggregates triggers a series of detrimental events, which results in synaptic alterations, neuronal cell loss, and significantly contributes toward disease pathogenesis. This Research Topic highlights the new approaches employed to develop therapeutics, which can effectively block or slow down the onset or progression of these fatal NDs. This manuscripts collection highlights the current advances in the field of neurodegenerative disorders, which may help in addressing some of the unanswered questions pertaining to this Research Topic. This collection of manuscripts is divided into three vital categories: (1) Disease mechanisms, (2) Therapeutic perspectives, and (3) Animal model(s). We hope that this topic may help discern the gaps, connect the missing links, improve our current understanding, knowledge related to this topic and open new avenues of research focuses to improve current treatments options against these deadly yet incurable disorders.
Acta Neuropathologica
Neurodegenerative diseases are an enormous public health problem, affecting tens of millions of people worldwide. Nearly all of these diseases are characterized by oligomerization and fibrillization of neuronal proteins, and there is great interest in therapeutic targeting of these aggregates. Here, we show that soluble aggregates of α-synuclein and tau bind to plate-immobilized PrP in vitro and on mouse cortical neurons, and that this binding requires at least one of the same N-terminal sites at which soluble Aβ aggregates bind. Moreover, soluble aggregates of tau, α-synuclein and Aβ cause both functional (impairment of LTP) and structural (neuritic dystrophy) compromise and these deficits are absent when PrP is ablated, knocked-down, or when neurons are pre-treated with anti-PrP blocking antibodies. Using an all-human experimental paradigm involving: (1) isogenic iPSC-derived neurons expressing or lackingPRNP, and (2) aqueous extracts from brains of individuals who died with Alzhe...
Journal of Neuropathology & Experimental Neurology
Recent studies in animal models demonstrate that certain misfolded proteins associated with neurodegenerative diseases can support templated misfolding of cognate native proteins, to propagate across neural systems, and to therefore have some of the properties of classical prion diseases like Creutzfeldt-Jakob disease. The National Institute of Aging convened a meeting to discuss the implications of these observations for research priorities. A summary of the discussion is presented here, with a focus on limitations of current knowledge, highlighting areas that appear to require further investigation in order to guide scientific practice while minimizing potential exposure or risk in the laboratory setting. The committee concluded that, based on all currently available data, although neurodegenerative disease-associated aggregates of several different non-prion proteins can be propagated from humans to experimental animals, there is currently insufficient evidence to suggest more th...