scholarly journals A metastable subproteome underlies inclusion formation in muscle proteinopathies

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Prajwal Ciryam ◽  
Matthew Antalek ◽  
Fernando Cid ◽  
Gian Gaetano Tartaglia ◽  
Christopher M. Dobson ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Pathological Feature ◽  
Protein Aggregate ◽  
Conformational Disorder ◽  
Aggregation Propensity ◽  
Inclusion Formation ◽  
Neuronal Protein ◽  
Conformational Disorders ◽  
The Brain ◽  
Protein Aggregate Myopathy

AbstractProtein aggregation is a pathological feature of neurodegenerative disorders. We previously demonstrated that protein inclusions in the brain are composed of supersaturated proteins, which are abundant and aggregation-prone, and form a metastable subproteome. It is not yet clear, however, whether this phenomenon is also associated with non-neuronal protein conformational disorders. To respond to this question, we analyzed proteomic datasets from biopsies of patients with genetic and acquired protein aggregate myopathy (PAM) by quantifying the changes in composition, concentration and aggregation propensity of proteins in the fibers containing inclusions and those surrounding them. We found that a metastable subproteome is present in skeletal muscle from healthy patients. The expression of this subproteome escalate as proteomic samples are taken more proximal to the pathologic inclusion, eventually exceeding its solubility limits and aggregating. While most supersaturated proteins decrease or maintain steady abundance across healthy fibers and inclusion-containing fibers, proteins within the metastable subproteome rise in abundance, suggesting that they escape regulation. Taken together, our results show in the context of a human conformational disorder that the supersaturation of a metastable subproteome underlies widespread aggregation and correlates with the histopathological state of the tissue.

scholarly journals Escalating protein supersaturation underlies inclusion formation in muscle proteinopathies

2019 ◽  
Author(s):  
Prajwal Ciryam ◽  
Matthew Antalek ◽  
Fernando Cid ◽  
Gian Gaetano Tartaglia ◽  
Christopher M. Dobson ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Selective Vulnerability ◽  
Aggregate Formation ◽  
Protein Aggregate ◽  
Aggregation Propensity ◽  
Inclusion Formation ◽  
Neuronal Protein ◽  
Quantitative Studies ◽  
Conformational Disorders ◽  
Protein Aggregate Myopathy

AbstractAbundant, aggregation prone or “supersaturated” proteins are a feature of neurodegeneration. Whether the principle of supersaturation can similarly explain the widespread aggregation that occurs in non-neuronal protein conformational disorders and underlies pathogenic protein aggregate formation is not established. To test this prediction we analyzed proteomic datasets of biopsies from genetic and acquired protein aggregate myopathy (PAM) patients by quantifying the changes in composition, concentration and aggregation propensity of proteins in the fibers containing inclusions and those surrounding them. We found that similar to neurodegeneration, a supersaturated subproteome of aggregate prone proteins is present in skeletal muscle from healthy patients. This subproteome escalates in degree of supersaturation as proteomic samples are taken more proximal to the pathologic inclusion, eventually exceeding its solubility limits and aggregating. While most supersaturated proteins decrease or maintain steady abundance across healthy fibers and inclusion containing fibers, supersaturated proteins within the aggregate subproteome rise in abundance, suggesting they escape normal regulation. We show in the context of a human conformational disorder that the level of supersaturation of a metastable subproteome helps to explain widespread aggregation and correlates with the histopathological state of the tissue.SignificanceIncreasing evidence implicates the phenomenon of protein supersaturation with the selective vulnerability of specific cells to protein misfolding disorders. Quantitative studies of this phenomenon, however, have only been possible post mortem in the case of neurodegenerative diseases. To overcome this limitation, we study here protein aggregate myopathies (PAMs), for which we were able to carry out systematic single fiber proteomic studies on patient-derived samples. We found not only that proteins associated with PAM inclusions are highly supersaturated in muscle but also that their supersaturation levels increases further in affected fibers. These results provide a clear illustration of how an escalation in supersaturation leads protein inclusions in vulnerable cells.

Brain Drug Delivery: Overcoming the Blood-brain Barrier to Treat Tauopathies

2020 ◽  
Vol 26 (13) ◽  
pp. 1448-1465 ◽  
Author(s):  
Jozef Hanes ◽  
Eva Dobakova ◽  
Petra Majerova
Keyword(s):  
Drug Delivery ◽  
Blood Brain Barrier ◽  
Neurodegenerative Disorders ◽  
Brain Barrier ◽  
Neuronal Function ◽  
Brain Drug Delivery ◽  
Naturally Occurring ◽  
Blood Brain ◽  
Traditional Approaches ◽  
The Brain

Tauopathies are neurodegenerative disorders characterized by the deposition of abnormal tau protein in the brain. The application of potentially effective therapeutics for their successful treatment is hampered by the presence of a naturally occurring brain protection layer called the blood-brain barrier (BBB). BBB represents one of the biggest challenges in the development of therapeutics for central nervous system (CNS) disorders, where sufficient BBB penetration is inevitable. BBB is a heavily restricting barrier regulating the movement of molecules, ions, and cells between the blood and the CNS to secure proper neuronal function and protect the CNS from dangerous substances and processes. Yet, these natural functions possessed by BBB represent a great hurdle for brain drug delivery. This review is concentrated on summarizing the available methods and approaches for effective therapeutics’ delivery through the BBB to treat neurodegenerative disorders with a focus on tauopathies. It describes the traditional approaches but also new nanotechnology strategies emerging with advanced medical techniques. Their limitations and benefits are discussed.

Role of Flavonoids in Neurodegenerative Disorders with Special Emphasis on Tangeritin

2019 ◽  
Vol 18 (8) ◽  
pp. 581-597 ◽  
Author(s):  
Ambreen Fatima ◽  
Yasir Hasan Siddique
Keyword(s):  
Medicinal Plants ◽  
Mechanism Of Action ◽  
Neurodegenerative Disorders ◽  
Treatment Strategies ◽  
Dietary Supplementation ◽  
Plant Polyphenols ◽  
Promising Candidate ◽  
Naturally Occurring ◽  
The Brain

Flavonoids are naturally occurring plant polyphenols found universally in all fruits, vegetables and medicinal plants. They have emerged as a promising candidate in the formulation of treatment strategies for various neurodegenerative disorders. The use of flavonoid rich plant extracts and food in dietary supplementation have shown favourable outcomes. The present review describes the types, properties and metabolism of flavonoids. Neuroprotective role of various flavonoids and the possible mechanism of action in the brain against the neurodegeneration have been described in detail with special emphasis on the tangeritin.

scholarly journals Optical Imaging of Beta-Amyloid Plaques in Alzheimer’s Disease

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 255
Author(s):  
Ziyi Luo ◽  
Hao Xu ◽  
Liwei Liu ◽  
Tymish Y. Ohulchanskyy ◽  
Junle Qu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Imaging ◽  
Imaging Techniques ◽  
High Sensitivity ◽  
Pathological Feature ◽  
Promising Tool ◽  
Abnormal Accumulation ◽  
Accumulation Mechanism ◽  
The Brain

Alzheimer’s disease (AD) is a multifactorial, irreversible, and incurable neurodegenerative disease. The main pathological feature of AD is the deposition of misfolded β-amyloid protein (Aβ) plaques in the brain. The abnormal accumulation of Aβ plaques leads to the loss of some neuron functions, further causing the neuron entanglement and the corresponding functional damage, which has a great impact on memory and cognitive functions. Hence, studying the accumulation mechanism of Aβ in the brain and its effect on other tissues is of great significance for the early diagnosis of AD. The current clinical studies of Aβ accumulation mainly rely on medical imaging techniques, which have some deficiencies in sensitivity and specificity. Optical imaging has recently become a research hotspot in the medical field and clinical applications, manifesting noninvasiveness, high sensitivity, absence of ionizing radiation, high contrast, and spatial resolution. Moreover, it is now emerging as a promising tool for the diagnosis and study of Aβ buildup. This review focuses on the application of the optical imaging technique for the determination of Aβ plaques in AD research. In addition, recent advances and key operational applications are discussed.

scholarly journals Human Monocytes Plasticity in Neurodegeneration

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 717
Author(s):  
Ilenia Savinetti ◽  
Angela Papagna ◽  
Maria Foti
Keyword(s):  
Neurodegenerative Disorders ◽  
Current Knowledge ◽  
Neurological Diseases ◽  
Surface Marker ◽  
First Line ◽  
Surface Marker Expression ◽  
Physiological Properties ◽  
Attractive Therapeutic Target ◽  
The Brain ◽  
Lateral Sclerosis

Monocytes play a crucial role in immunity and tissue homeostasis. They constitute the first line of defense during the inflammatory process, playing a role in the pathogenesis and progression of diseases, making them an attractive therapeutic target. They are heterogeneous in morphology and surface marker expression, which suggest different molecular and physiological properties. Recent evidences have demonstrated their ability to enter the brain, and, as a consequence, their hypothetical role in different neurodegenerative diseases. In this review, we will discuss the current knowledge about the correlation between monocyte dysregulation in the brain and/or in the periphery and neurological diseases in humans. Here we will focus on the most common neurodegenerative disorders, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and multiple sclerosis.

scholarly journals A novel dephosphorylation targeting chimera selectively promoting tau removal in tauopathies

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jie Zheng ◽  
Na Tian ◽  
Fei Liu ◽  
Yidian Zhang ◽  
Jingfen Su ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Protein Phosphatase ◽  
High Efficiency ◽  
Microtubule Assembly ◽  
Hyperphosphorylated Tau ◽  
Phosphatase 2A ◽  
Dependent Learning ◽  
The Brain

AbstractIntraneuronal accumulation of hyperphosphorylated tau is a hallmark pathology shown in over twenty neurodegenerative disorders, collectively termed as tauopathies, including the most common Alzheimer’s disease (AD). Therefore, selectively removing or reducing hyperphosphorylated tau is promising for therapies of AD and other tauopathies. Here, we designed and synthesized a novel DEPhosphorylation TArgeting Chimera (DEPTAC) to specifically facilitate the binding of tau to Bα-subunit-containing protein phosphatase 2A (PP2A-Bα), the most active tau phosphatase in the brain. The DEPTAC exhibited high efficiency in dephosphorylating tau at multiple AD-associated sites and preventing tau accumulation both in vitro and in vivo. Further studies revealed that DEPTAC significantly improved microtubule assembly, neurite plasticity, and hippocampus-dependent learning and memory in transgenic mice with inducible overexpression of truncated and neurotoxic human tau N368. Our data provide a strategy for selective removal of the hyperphosphorylated tau, which sheds new light for the targeted therapy of AD and related-tauopathies.

scholarly journals Environmental and genetic factors support the dissociation between α-synuclein aggregation and toxicity

2016 ◽  
Vol 113 (42) ◽  
pp. E6506-E6515 ◽  
Author(s):  
Anna Villar-Piqué ◽  
Tomás Lopes da Fonseca ◽  
Ricardo Sant’Anna ◽  
Éva Mónika Szegö ◽  
Luis Fonseca-Ornelas ◽  
...  
Keyword(s):  
Genetic Factors ◽  
Strong Support ◽  
Structural Features ◽  
Biological Properties ◽  
Neuronal Cultures ◽  
Unique Combination ◽  
Primary Neuronal Cultures ◽  
Intrinsic Factors ◽  
Inclusion Formation ◽  
Neuronal Protein

Synucleinopathies are a group of progressive disorders characterized by the abnormal aggregation and accumulation of α-synuclein (aSyn), an abundant neuronal protein that can adopt different conformations and biological properties. Recently, aSyn pathology was shown to spread between neurons in a prion-like manner. Proteins like aSyn that exhibit self-propagating capacity appear to be able to adopt different stable conformational states, known as protein strains, which can be modulated both by environmental and by protein-intrinsic factors. Here, we analyzed these factors and found that the unique combination of the neurodegeneration-related metal copper and the pathological H50Q aSyn mutation induces a significant alteration in the aggregation properties of aSyn. We compared the aggregation of WT and H50Q aSyn with and without copper, and assessed the effects of the resultant protein species when applied to primary neuronal cultures. The presence of copper induces the formation of structurally different and less-damaging aSyn aggregates. Interestingly, these aggregates exhibit a stronger capacity to induce aSyn inclusion formation in recipient cells, which demonstrates that the structural features of aSyn species determine their effect in neuronal cells and supports a lack of correlation between toxicity and inclusion formation. In total, our study provides strong support in favor of the hypothesis that protein aggregation is not a primary cause of cytotoxicity.

scholarly journals The eIF2α kinase HRI triggers the autophagic clearance of cytosolic protein aggregates

2020 ◽  
pp. jbc.RA120.014415
Author(s):  
Tapas Mukherjee ◽  
Valeria Ramaglia ◽  
Mena Abdel-Nour ◽  
Athanasia A Bianchi ◽  
Jessica Tsalikis ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Lewy Bodies ◽  
Protein Aggregates ◽  
Distal Colon ◽  
Ubiquitin Proteasome System ◽  
Pathological Feature ◽  
Protein Aggregate ◽  
Sensory Afferents ◽  
Cytosolic Protein ◽  
Eif2α Kinase

Large cytosolic protein aggregates are removed by two main cellular processes, autophagy and the ubiquitin-proteasome system (UPS), and defective clearance of these protein aggregates results in proteotoxicity and cell death. Recently, we found that the eIF2α kinase heme-regulated inhibitory (HRI) induced a cytosolic unfolded protein response (cUPR) to prevent aggregation of innate immune signalosomes, but whether HRI acts as a general sensor of proteotoxicity in the cytosol remains unclear. Here we show that HRI controls autophagy to clear cytosolic protein aggregates when the UPS is inhibited. We further report that silencing HRI expression resulted in decreased levels of BAG3 and HSPB8, two proteins involved in chaperone-assisted selective autophagy (CASA), suggesting that HRI controls proteostasis in the cytosol at least in part through CASA. Moreover, knocking down the expression of HRI resulted in cytotoxic accumulation of over-expressed α-synuclein, a protein known to aggregate in Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. In agreement with these data, protein aggregate accumulation and microglia activation were observed in the spinal cord white matter of 7-month old Hri-/- mice as compared to Hri+/+ littermates. Moreover, aged Hri-/- mice showed accumulation of misfolded α-synuclein, indicative of misfolded proteins, in the lateral collateral pathway, a region of the sacral spinal cord horn that receives visceral sensory afferents from the bladder and distal colon, a pathological feature common to α-synucleinopathies in humans. Together, these results suggest that HRI contributes to a general cUPR that could be leveraged to bolster the clearance of cytotoxic protein aggregates.

scholarly journals RCAN1 Regulates Mitochondrial Function and Increases Susceptibility to Oxidative Stress in Mammalian Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Heshan Peiris ◽  
Daphne Dubach ◽  
Claire F. Jessup ◽  
Petra Unterweger ◽  
Ravinarayan Raghupathi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Function ◽  
Neurodegenerative Disorders ◽  
Mammalian Cells ◽  
Cell Function ◽  
Cellular Energy ◽  
Mitochondrial Ros ◽  
Ros Accumulation ◽  
The Brain ◽  
Increased Susceptibility

Mitochondria are the primary site of cellular energy generation and reactive oxygen species (ROS) accumulation. Elevated ROS levels are detrimental to normal cell function and have been linked to the pathogenesis of neurodegenerative disorders such as Down's syndrome (DS) and Alzheimer’s disease (AD). RCAN1 is abundantly expressed in the brain and overexpressed in brain of DS and AD patients. Data from nonmammalian species indicates that increased RCAN1 expression results in altered mitochondrial function and that RCAN1 may itself regulate neuronal ROS production. In this study, we have utilized mice overexpressing RCAN1RCAN1oxand demonstrate an increased susceptibility of neurons from these mice to oxidative stress. Mitochondria from these mice are more numerous and smaller, indicative of mitochondrial dysfunction, and mitochondrial membrane potential is altered under conditions of oxidative stress. We also generated a PC12 cell line overexpressing RCAN1PC12RCAN1. Similar toRCAN1oxneurons,PC12RCAN1cells have an increased susceptibility to oxidative stress and produce more mitochondrial ROS. This study demonstrates that increasing RCAN1 expression alters mitochondrial function and increases the susceptibility of neurons to oxidative stress in mammalian cells. These findings further contribute to our understanding of RCAN1 and its potential role in the pathogenesis of neurodegenerative disorders such as AD and DS.

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