Prions and Neurodegenerative Diseases: A Focus on Alzheimer’s Disease

2021 ◽  
pp. 1-16
Author(s):  
Alessio Crestini ◽  
Francesca Santilli ◽  
Stefano Martellucci ◽  
Elena Carbone ◽  
Maurizio Sorice ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Amyloid Β ◽  
Specific Protein ◽  
Cellular Prion Protein ◽  
Aβ Oligomers ◽  
The Central Nervous System ◽  
Induced Signal

Specific protein misfolding and aggregation are mechanisms underlying various neurodegenerative diseases such as prion disease and Alzheimer’s disease (AD). The misfolded proteins are involved in prions, amyloid-β (Aβ), tau, and α-synuclein disorders; they share common structural, biological, and biochemical characteristics, as well as similar mechanisms of aggregation and self-propagation. Pathological features of AD include the appearance of plaques consisting of deposition of protein Aβ and neurofibrillary tangles formed by the hyperphosphorylated tau protein. Although it is not clear how protein aggregation leads to AD, we are learning that the cellular prion protein (PrPC) plays an important role in the pathogenesis of AD. Herein, we first examined the pathogenesis of prion and AD with a focus on the contribution of PrPC to the development of AD. We analyzed the mechanisms that lead to the formation of a high affinity bond between Aβ oligomers (AβOs) and PrPC. Also, we studied the role of PrPC as an AβO receptor that initiates an AβO-induced signal cascade involving mGluR5, Fyn, Pyk2, and eEF2K linking Aβ and tau pathologies, resulting in the death of neurons in the central nervous system. Finally, we have described how the PrPC-AβOs interaction can be used as a new potential therapeutic target for the treatment of PrPC-dependent AD.

scholarly journals Cu-Based Turn-on Fluorescent Sensors for Cu-rich Amyloid β Aggregates

2021 ◽  
Author(s):  
Yiran Huang ◽  
Liang Sun ◽  
Liviu M. Mirica
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Fluorescence Imaging ◽  
Protein Misfolding ◽  
Picolinic Acid ◽  
Amyloid Β ◽  
Fluorescent Sensors ◽  
Aβ Oligomers ◽  
Turn On ◽  
Aβ Aggregation

<div>Protein misfolding and metal dishomeostasis are two key</div><div>pathological factors of Alzheimer’s disease. Previous studies have showed that Cu‐mediated Aβ aggregation pathways lead to formation of neurotoxic Aβ oligomers. Herein, we reported a series of picolinic acid‐based Cu‐activatable sensors, which can be used for the fluorescence imaging of Cu‐rich Aβ aggregates.</div>

scholarly journals Soluble Prion Peptide 107–120 Protects Neuroblastoma SH-SY5Y Cells against Oligomers Associated with Alzheimer’s Disease

2020 ◽  
Vol 21 (19) ◽  
pp. 7273
Author(s):  
Elham Rezvani Boroujeni ◽  
Seyed Masoud Hosseini ◽  
Giulia Fani ◽  
Cristina Cecchi ◽  
Fabrizio Chiti
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Potential ◽  
Critical Role ◽  
Amyloid Β ◽  
Cellular Prion Protein ◽  
Ros Generation ◽  
Aβ Oligomers ◽  
Self Recognition ◽  
High Affinity Receptor

Alzheimer’s disease (AD) is the most prevalent form of dementia and soluble amyloid β (Aβ) oligomers are thought to play a critical role in AD pathogenesis. Cellular prion protein (PrPC) is a high-affinity receptor for Aβ oligomers and mediates some of their toxic effects. The N-terminal region of PrPC can interact with Aβ, particularly the region encompassing residues 95–110. In this study, we identified a soluble and unstructured prion-derived peptide (PrP107–120) that is external to this region of the sequence and was found to successfully reduce the mitochondrial impairment, intracellular ROS generation and cytosolic Ca2+ uptake induced by oligomeric Aβ42 ADDLs in neuroblastoma SH-SY5Y cells. PrP107–120 was also found to rescue SH-SY5Y cells from Aβ42 ADDL internalization. The peptide did not change the structure and aggregation pathway of Aβ42 ADDLs, did not show co-localization with Aβ42 ADDLs in the cells and showed a partial colocalization with the endogenous cellular PrPC. As a sequence region that is not involved in Aβ binding but in PrP self-recognition, the peptide was suggested to protect against the toxicity of Aβ42 oligomers by interfering with cellular PrPC and/or activating a signaling that protected the cells. These results strongly suggest that PrP107–120 has therapeutic potential for AD.

scholarly journals Rational design of a conformation-specific antibody for the quantification of Aβ oligomers

2020 ◽  
Vol 117 (24) ◽  
pp. 13509-13518 ◽  
Author(s):  
Francesco A. Aprile ◽  
Pietro Sormanni ◽  
Marina Podpolny ◽  
Shianne Chhangur ◽  
Lisa-Maria Needham ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protein Misfolding ◽  
Rational Design ◽  
Design Method ◽  
Amyloid Β ◽  
In Vitro Assays ◽  
Aβ Oligomers ◽  
Detection And Quantification

Protein misfolding and aggregation is the hallmark of numerous human disorders, including Alzheimer’s disease. This process involves the formation of transient and heterogeneous soluble oligomers, some of which are highly cytotoxic. A major challenge for the development of effective diagnostic and therapeutic tools is thus the detection and quantification of these elusive oligomers. Here, to address this problem, we develop a two-step rational design method for the discovery of oligomer-specific antibodies. The first step consists of an “antigen scanning” phase in which an initial panel of antibodies is designed to bind different epitopes covering the entire sequence of a target protein. This procedure enables the determination through in vitro assays of the regions exposed in the oligomers but not in the fibrillar deposits. The second step involves an “epitope mining” phase, in which a second panel of antibodies is designed to specifically target the regions identified during the scanning step. We illustrate this method in the case of the amyloid β (Aβ) peptide, whose oligomers are associated with Alzheimer’s disease. Our results show that this approach enables the accurate detection and quantification of Aβ oligomers in vitro, and inCaenorhabditis elegansand mouse hippocampal tissues.

scholarly journals Cu-Based Turn-on Fluorescent Sensors for Cu-rich Amyloid β Aggregates

2021 ◽  
Author(s):  
Yiran Huang ◽  
Liang Sun ◽  
Liviu M. Mirica
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Fluorescence Imaging ◽  
Protein Misfolding ◽  
Picolinic Acid ◽  
Amyloid Β ◽  
Fluorescent Sensors ◽  
Aβ Oligomers ◽  
Turn On ◽  
Aβ Aggregation

<div>Protein misfolding and metal dishomeostasis are two key</div><div>pathological factors of Alzheimer’s disease. Previous studies have showed that Cu‐mediated Aβ aggregation pathways lead to formation of neurotoxic Aβ oligomers. Herein, we reported a series of picolinic acid‐based Cu‐activatable sensors, which can be used for the fluorescence imaging of Cu‐rich Aβ aggregates.</div>

Is it All Said for NSAIDs in Alzheimer’s Disease? Role of Mitochondrial Calcium Uptake

2018 ◽  
Vol 15 (6) ◽  
pp. 504-510 ◽  
Author(s):  
Sara Sanz-Blasco ◽  
Maria Calvo-Rodríguez ◽  
Erica Caballero ◽  
Monica Garcia-Durillo ◽  
Lucia Nunez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Death ◽  
Amyloid Β ◽  
Epidemiological Data ◽  
Amyloid Β Peptide ◽  
Aβ Oligomers ◽  
Mitochondrial Potential ◽  
Disease Modifying Drugs ◽  
Definitive Evidence

Objectives: Epidemiological data suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may protect against Alzheimer's disease (AD). Unfortunately, recent trials have failed in providing compelling evidence of neuroprotection. Discussion as to why NSAIDs effectivity is uncertain is ongoing. Possible explanations include the view that NSAIDs and other possible disease-modifying drugs should be provided before the patients develop symptoms of AD or cognitive decline. In addition, NSAID targets for neuroprotection are unclear. Both COX-dependent and independent mechanisms have been proposed, including γ-secretase that cleaves the amyloid precursor protein (APP) and yields amyloid β peptide (Aβ). Methods: We have proposed a neuroprotection mechanism for NSAIDs based on inhibition of mitochondrial Ca2+ overload. Aβ oligomers promote Ca2+ influx and mitochondrial Ca2+ overload leading to neuron cell death. Several non-specific NSAIDs including ibuprofen, sulindac, indomethacin and Rflurbiprofen depolarize mitochondria in the low µM range and prevent mitochondrial Ca2+ overload induced by Aβ oligomers and/or N-methyl-D-aspartate (NMDA). However, at larger concentrations, NSAIDs may collapse mitochondrial potential (ΔΨ) leading to cell death. Results: Accordingly, this mechanism may explain neuroprotection at low concentrations and damage at larger doses, thus providing clues on the failure of promising trials. Perhaps lower NSAID concentrations and/or alternative compounds with larger dynamic ranges should be considered for future trials to provide definitive evidence of neuroprotection against AD.

scholarly journals Phosphoinositides signaling modulates microglial actin remodeling and phagocytosis in Alzheimer’s disease

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Smita Eknath Desale ◽  
Subashchandrabose Chinnathambi
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Signaling Pathways ◽  
Amyloid Β ◽  
Dietary Fatty Acids ◽  
Receptor Expression ◽  
Actin Binding ◽  
Actin Remodeling ◽  
Protein Deposits

AbstractAlzheimer’s disease is one of the neurodegenerative diseases, characterized by the accumulation of abnormal protein deposits, which disrupts signal transduction in neurons and other glia cells. The pathological protein in neurodegenerative diseases, Tau and amyloid-β contribute to the disrupted microglial signaling pathways, actin cytoskeleton, and cellular receptor expression. The important secondary messenger lipids i.e., phosphatidylinositols are largely affected by protein deposits of amyloid-β in Alzheimer’s disease. Phosphatidylinositols are the product of different phosphatidylinositol kinases and the state of phosphorylation at D3, D4, and D5 positions of inositol ring. Phosphatidylinositol 3,4,5-triphosphate (PI 3, 4, 5-P3) involves in phagocytic cup formation, cell polarization, whereas Phosphatidylinositol 4,5-bisphosphate (PI 4, 5-P2)-mediates the process of phagosomes formation and further its fusion with early endosome.. The necessary activation of actin-binding proteins such as Rac, WAVE complex, and ARP2/3 complex for the actin polymerization in the process of phagocytosis, migration is regulated and maintained by PI 3, 4, 5-P3 and PI 4, 5-P2. The ratio and types of fatty acid intake can influence the intracellular secondary lipid messengers along with the cellular content of phaphatidylcholine and phosphatidylethanolamine. The Amyloid-β deposits and extracellular Tau seeds disrupt phosphatidylinositides level and actin cytoskeletal network that hamper microglial-signaling pathways in AD. We hypothesize that being a lipid species intracellular levels of phosphatidylinositol would be regulated by dietary fatty acids. Further we are interested to understand phosphoinositide-based signaling cascades in phagocytosis and actin remodeling.

Destabilization of Alzheimer’s Aβ42 protofibrils with acyclovir, carmustine, curcumin, and tetracycline: Insights from molecular dynamics simulations

2021 ◽  
Author(s):  
Ishrat Jahan ◽  
Shahid M Nayeem
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Dynamics ◽  
Neurodegenerative Diseases ◽  
Molecular Dynamics Simulations ◽  
Amyloid Β ◽  
Neural Tissue ◽  
Amyloid Β Peptide ◽  
Characteristic Symptom ◽  
Dynamics Simulations

One of the most common dementia among neurodegenerative diseases is Alzheimer’s disease (AD). The characteristic symptom of AD is the deposition and aggregation of amyloid-β-peptide in the neural tissue. A...

scholarly journals Diagnosing Alzheimer’s Disease from Circulating Blood Leukocytes Using a Fluorescent Amyloid Probe

2021 ◽  
pp. 1-14
Author(s):  
Stefanie A.G. Black ◽  
Anastasiia A. Stepanchuk ◽  
George W. Templeton ◽  
Yda Hernandez ◽  
Tomoko Ota ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protein Misfolding ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Amyloid Β ◽  
Csf Biomarkers ◽  
Blood Leukocytes ◽  
Peripheral Blood Mononuclear ◽  
The Brain

Background: Toxic amyloid-β (Aβ) peptides aggregate into higher molecular weight assemblies and accumulate not only in the extracellular space, but also in the walls of blood vessels in the brain, increasing their permeability, and promoting immune cell migration and activation. Given the prominent role of the immune system, phagocytic blood cells may contact pathological brain materials. Objective: To develop a novel method for early Alzheimer’s disease (AD) detection, we used blood leukocytes, that could act as “sentinels” after trafficking through the brain microvasculature, to detect pathological amyloid by labelling with a conformationally-sensitive fluorescent amyloid probe and imaging with confocal spectral microscopy. Methods: Formalin-fixed peripheral blood mononuclear cells (PBMCs) from cognitively healthy control (HC) subjects, mild cognitive impairment (MCI) and AD patients were stained with the fluorescent amyloid probe K114, and imaged. Results were validated against cerebrospinal fluid (CSF) biomarkers and clinical diagnosis. Results: K114-labeled leukocytes exhibited distinctive fluorescent spectral signatures in MCI/AD subjects. Comparing subjects with single CSF biomarker-positive AD/MCI to negative controls, our technique yielded modest AUCs, which improved to the 0.90 range when only MCI subjects were included in order to measure performance in an early disease state. Combining CSF Aβ 42 and t-Tau metrics further improved the AUC to 0.93. Conclusion: Our method holds promise for sensitive detection of AD-related protein misfolding in circulating leukocytes, particularly in the early stages of disease.

scholarly journals Prion protein stabilizes amyloid-β (Aβ) oligomers and enhances Aβ neurotoxicity in aDrosophilamodel of Alzheimer's disease

2018 ◽  
Vol 293 (34) ◽  
pp. 13090-13099 ◽  
Author(s):  
Nadine D. Younan ◽  
Ko-Fan Chen ◽  
Ruth-Sarah Rose ◽  
Damian C. Crowther ◽  
John H. Viles
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Prion Protein ◽  
Amyloid Β ◽  
Aβ Oligomers

scholarly journals The inhibition of cellular toxicity of amyloid-β by dissociated transthyretin

2020 ◽  
Vol 295 (41) ◽  
pp. 14015-14024 ◽  
Author(s):  
Qin Cao ◽  
Daniel H. Anderson ◽  
Wilson Y. Liang ◽  
Joshua Chou ◽  
Lorena Saelices
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protective Effect ◽  
Amyloid Β ◽  
Inhibitory Effect ◽  
Aβ Oligomers ◽  
Cellular Toxicity ◽  
Computational Docking

The protective effect of transthyretin (TTR) on cellular toxicity of β-amyloid (Aβ) has been previously reported. TTR is a tetrameric carrier of thyroxine in blood and cerebrospinal fluid, the pathogenic aggregation of which causes systemic amyloidosis. However, studies have documented a protective effect of TTR against cellular toxicity of pathogenic Aβ, a protein associated with Alzheimer's disease. TTR binds Aβ, alters its aggregation, and inhibits its toxicity both in vitro and in vivo. In this study, we investigate whether the amyloidogenic ability of TTR and its antiamyloid inhibitory effect are associated. Using protein aggregation and cytotoxicity assays, we found that the dissociation of the TTR tetramer, required for its amyloid pathogenesis, is also necessary to prevent cellular toxicity from Aβ oligomers. These findings suggest that the Aβ-binding site of TTR may be hidden in its tetrameric form. Aided by computational docking and peptide screening, we identified a TTR segment that is capable of altering Aβ aggregation and toxicity, mimicking TTR cellular protection. EM, immune detection analysis, and assessment of aggregation and cytotoxicity revealed that the TTR segment inhibits Aβ oligomer formation and also promotes the formation of nontoxic, nonamyloid amorphous aggregates, which are more sensitive to protease digestion. Finally, this segment also inhibits seeding of Aβ catalyzed by Aβ fibrils extracted from the brain of an Alzheimer's patient. Together, these findings suggest that mimicking the inhibitory effect of TTR with peptide-based therapeutics represents an additional avenue to explore for the treatment of Alzheimer's disease.

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