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1.
Neurochem Int ; 177: 105762, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38723901

ABSTRACT

Linalool is a neuroprotective monoterpene found in essential oils from aromatic plants. Linalool's effectiveness in AD animal models has been established previously, but its mechanisms of action remain unclear. Therefore, this study aims to investigate whether linalool binds directly to the amyloid beta (Aß) fibrils to understand it's role in preventing neurodegeneration. The anti-aggregation ability of Linalool was determined using Dithiothreitol (DTT), and thermal aggregation assays followed by Thioflavin T (ThT) binding assay. AD animals were treated with Linalool, and Thioflavin T staining was used to check the binding of linalool to Aß fibrils in rat brain tissue sections. Preliminary studies revealed the anti-aggregation potential of linalool under the thermal and chemical stimulus. Further, in ThT binding assay Linalool inhibited Aß aggregation, binding directly to Aß fibrils. The reduced fluorescence intensity of ThT in AD brain tissues following linalool administration, highlights its neuroprotective potential as a therapeutic agent for AD.


Subject(s)
Acyclic Monoterpenes , Amyloid beta-Peptides , Amyloid beta-Peptides/metabolism , Amyloid beta-Peptides/antagonists & inhibitors , Acyclic Monoterpenes/pharmacology , Animals , Rats , Male , Monoterpenes/pharmacology , Monoterpenes/therapeutic use , Monoterpenes/chemistry , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Neuroprotective Agents/pharmacology , Brain/metabolism , Brain/drug effects , Rats, Wistar , Protein Aggregates/drug effects , Protein Aggregates/physiology , Rats, Sprague-Dawley , Protein Aggregation, Pathological/drug therapy , Protein Aggregation, Pathological/metabolism , Protein Aggregation, Pathological/prevention & control
3.
Acta Neuropathol ; 143(1): 55-73, 2022 01.
Article in English | MEDLINE | ID: mdl-34741635

ABSTRACT

Alpha synuclein has a key role in the pathogenesis of Parkinson's disease (PD), Dementia with Lewy Bodies (LBD) and Multiple System Atrophy (MSA). Immunotherapies aiming at neutralising toxic αSyn species are being investigated in the clinic as potential disease modifying therapies for PD and other synucleinopathies. In this study, the effects of active immunisation against αSyn with the UB-312 vaccine were investigated in the Thy1SNCA/15 mouse model of PD. Young transgenic and wild-type mice received an immunisation regimen over a period of 6 weeks, then observed for an additional 9 weeks. Behavioural assessment was conducted before immunisation and at 15 weeks after the first dose. UB-312 immunisation prevented the development of motor impairment in the wire test and challenging beam test, which was associated with reduced levels of αSyn oligomers in the cerebral cortex, hippocampus and striatum of Thy1SNCA/15 mice. UB-312 immunotherapy resulted in a significant reduction of theαSyn load in the colon, accompanied by a reduction in enteric glial cell reactivity in the colonic ganglia. Our results demonstrate that immunisation with UB-312 prevents functional deficits and both central and peripheral pathology in Thy1SNCA/15 mice.


Subject(s)
Parkinsonian Disorders/pathology , Protein Aggregation, Pathological/prevention & control , Vaccines, Subunit/pharmacology , alpha-Synuclein/antagonists & inhibitors , Animals , Brain/pathology , Disease Models, Animal , Humans , Intestines/pathology , Mice , Mice, Transgenic , Vaccination/methods
4.
Int J Mol Sci ; 22(24)2021 Dec 13.
Article in English | MEDLINE | ID: mdl-34948195

ABSTRACT

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopamine neurons and the deposition of misfolded proteins known as Lewy bodies (LBs), which contain α-synuclein (α-syn). The causes and molecular mechanisms of PD are not clearly understood to date. However, misfolded proteins, oxidative stress, and impaired autophagy are believed to play important roles in the pathogenesis of PD. Importantly, α-syn is considered a key player in the development of PD. The present study aimed to assess the role of Ellagic acid (EA), a polyphenol found in many fruits, on α-syn aggregation and toxicity. Using thioflavin and seeding polymerization assays, in addition to electron microscopy, we found that EA could dramatically reduce α-syn aggregation. Moreover, EA significantly mitigated the aggregated α-syn-induced toxicity in SH-SY5Y cells and thus enhanced their viability. Mechanistically, these cytoprotective effects of EA are mediated by the suppression of apoptotic proteins BAX and p53 and a concomitant increase in the anti-apoptotic protein, BCL-2. Interestingly, EA was able to activate autophagy in SH-SY5Y cells, as evidenced by normalized/enhanced expression of LC3-II, p62, and pAKT. Together, our findings suggest that EA may attenuate α-syn toxicity by preventing aggregation and improving viability by restoring autophagy and suppressing apoptosis.


Subject(s)
Ellagic Acid/pharmacology , Protein Aggregation, Pathological/prevention & control , alpha-Synuclein/metabolism , Apoptosis/physiology , Autophagy/physiology , Cell Line, Tumor , Dopaminergic Neurons/metabolism , Ellagic Acid/metabolism , Humans , Lewy Bodies/metabolism , Neurodegenerative Diseases/metabolism , Parkinson Disease/metabolism , Protein Aggregates/physiology , Protein Aggregation, Pathological/metabolism , alpha-Synuclein/physiology
5.
PLoS One ; 16(11): e0260519, 2021.
Article in English | MEDLINE | ID: mdl-34847196

ABSTRACT

Endoplasmic reticulum (ER) stress is associated with acute kidney injury (AKI) caused by various mechanisms, including antibiotics, non-steroidal anti-inflammatory drugs, cisplatin, and radiocontrast. Tunicamycin (TM) is a nucleoside antibiotic that induces ER stress and is a commonly used model of AKI. 4-phenylbutyrate (4-PBA) is a chemical chaperone and histone deacetylase (HDAC) inhibitor and has been shown to protect the kidney from ER stress, apoptosis, and structural damage in a tunicamycin model of AKI. The renal protection provided by 4-PBA is attributed to its ability to prevent misfolded protein aggregation and inhibit ER stress; however, the HDAC inhibitor effects of 4-PBA have not been examined in the TM-induced model of AKI. As such, the main objective of this study was to determine if histone hyperacetylation provides any protective effects against TM-mediated AKI. The FDA-approved HDAC inhibitor vorinostat was used, as it has no ER stress inhibitory effects and therefore the histone hyperacetylation properties alone could be investigated. In vitro work demonstrated that vorinostat inhibited histone deacetylation in cultured proximal tubular cells but did not prevent ER stress or protein aggregation induced by TM. Vorinostat induced a significant increase in cell death, and exacerbated TM-mediated total cell death and apoptotic cell death. Wild type male mice were treated with TM (0.5 mg/kg, intraperitoneal injection), with or without vorinostat (50 mg/kg/day) or 4-PBA (1 g/kg/day). Mice treated with 4-PBA or vorinostat exhibited similar levels of histone hyperacetylation. Expression of the pro-apoptotic protein CHOP was induced with TM, and not inhibited by vorinostat. Further, vorinostat did not prevent any renal damage or decline in renal function caused by tunicamycin. These data suggest that the protective mechanisms found by 4-PBA are primarily due to its molecular chaperone properties, and the HDAC inhibitors used did not provide any protection against renal injury caused by ER stress.


Subject(s)
Acute Kidney Injury , Endoplasmic Reticulum Stress/drug effects , Histone Deacetylase Inhibitors/pharmacology , Tunicamycin/adverse effects , Vorinostat/pharmacology , Acute Kidney Injury/chemically induced , Acute Kidney Injury/metabolism , Acute Kidney Injury/prevention & control , Animals , Cell Line , Disease Models, Animal , Male , Mice , Protein Aggregation, Pathological/chemically induced , Protein Aggregation, Pathological/metabolism , Protein Aggregation, Pathological/pathology , Protein Aggregation, Pathological/prevention & control , Tunicamycin/pharmacology
6.
Nature ; 597(7874): 132-137, 2021 09.
Article in English | MEDLINE | ID: mdl-34408321

ABSTRACT

Protein quality control systems are crucial for cellular function and organismal health. At present, most known protein quality control systems are multicomponent machineries that operate via ATP-regulated interactions with non-native proteins to prevent aggregation and promote folding1, and few systems that can broadly enable protein folding by a different mechanism have been identified. Moreover, proteins that contain the extensively charged poly-Asp/Glu (polyD/E) region are common in eukaryotic proteomes2, but their biochemical activities remain undefined. Here we show that DAXX, a polyD/E protein that has been implicated in diverse cellular processes3-10, possesses several protein-folding activities. DAXX prevents aggregation, solubilizes pre-existing aggregates and unfolds misfolded species of model substrates and neurodegeneration-associated proteins. Notably, DAXX effectively prevents and reverses aggregation of its in vivo-validated client proteins, the tumour suppressor p53 and its principal antagonist MDM2. DAXX can also restore native conformation and function to tumour-associated, aggregation-prone p53 mutants, reducing their oncogenic properties. These DAXX activities are ATP-independent and instead rely on the polyD/E region. Other polyD/E proteins, including ANP32A and SET, can also function as stand-alone, ATP-independent molecular chaperones, disaggregases and unfoldases. Thus, polyD/E proteins probably constitute a multifunctional protein quality control system that operates via a distinctive mechanism.


Subject(s)
Co-Repressor Proteins/metabolism , Molecular Chaperones/metabolism , Protein Folding , Animals , Cell Line , Cells/metabolism , Evolution, Molecular , Humans , Models, Molecular , Mutation , Protein Aggregates , Protein Aggregation, Pathological/prevention & control , Protein Conformation , Protein Domains , Protein Unfolding , Proteostasis Deficiencies/prevention & control , Proto-Oncogene Proteins c-mdm2/chemistry , Proto-Oncogene Proteins c-mdm2/metabolism , Tumor Suppressor Protein p53/chemistry , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
7.
Commun Biol ; 4(1): 843, 2021 07 07.
Article in English | MEDLINE | ID: mdl-34234268

ABSTRACT

Age-related changes in cellular metabolism can affect brain homeostasis, creating conditions that are permissive to the onset and progression of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Although the roles of metabolites have been extensively studied with regard to cellular signaling pathways, their effects on protein aggregation remain relatively unexplored. By computationally analysing the Human Metabolome Database, we identified two endogenous metabolites, carnosine and kynurenic acid, that inhibit the aggregation of the amyloid beta peptide (Aß) and rescue a C. elegans model of Alzheimer's disease. We found that these metabolites act by triggering a cytosolic unfolded protein response through the transcription factor HSF-1 and downstream chaperones HSP40/J-proteins DNJ-12 and DNJ-19. These results help rationalise previous observations regarding the possible anti-ageing benefits of these metabolites by providing a mechanism for their action. Taken together, our findings provide a link between metabolite homeostasis and protein homeostasis, which could inspire preventative interventions against neurodegenerative disorders.


Subject(s)
Alzheimer Disease/metabolism , Caenorhabditis elegans/metabolism , Carnosine/metabolism , Disease Models, Animal , Kynurenic Acid/metabolism , Unfolded Protein Response/physiology , Alzheimer Disease/prevention & control , Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/metabolism , Animals , Caenorhabditis elegans Proteins/metabolism , Carnosine/pharmacology , Cytosol/metabolism , HSP40 Heat-Shock Proteins/metabolism , Humans , Kynurenic Acid/pharmacology , Protein Aggregates , Protein Aggregation, Pathological/prevention & control , Transcription Factors/metabolism , Unfolded Protein Response/drug effects
8.
Nat Struct Mol Biol ; 28(6): 465-473, 2021 06.
Article in English | MEDLINE | ID: mdl-34099940

ABSTRACT

Biomolecular condensates that form via phase separation are increasingly regarded as coordinators of cellular reactions that regulate a wide variety of biological phenomena. Mounting evidence suggests that multiple steps of the RNA life cycle are organized within RNA-binding protein-rich condensates. In this Review, we discuss recent insights into the influence of phase separation on RNA biology, which has implications for basic cell biology, the pathogenesis of human diseases and the development of novel therapies.


Subject(s)
RNA-Binding Proteins/chemistry , RNA/chemistry , Ribonucleoproteins/chemistry , Animals , Cell Nucleus/chemistry , Cell Nucleus/physiology , Cytoplasm/chemistry , Cytoplasm/physiology , Humans , Intrinsically Disordered Proteins/chemistry , Mammals/metabolism , Neoplasm Proteins/chemistry , Neoplasms/metabolism , Neurodegenerative Diseases/metabolism , Osmolar Concentration , Phase Transition , Protein Aggregation, Pathological/prevention & control , Protein Conformation , Protein Domains , Protein Isoforms/chemistry , Protein Processing, Post-Translational , RNA/metabolism , RNA Splicing , RNA, Neoplasm/metabolism , Structure-Activity Relationship
9.
J Biol Chem ; 296: 100663, 2021.
Article in English | MEDLINE | ID: mdl-33862084

ABSTRACT

α-synuclein (αSyn) is a protein known to form intracellular aggregates during the manifestation of Parkinson's disease. Previously, it was shown that αSyn aggregation was strongly suppressed in the midbrain region of mice that did not possess the gene encoding the lipid transport protein fatty acid binding protein 3 (FABP3). An interaction between these two proteins was detected in vitro, suggesting that FABP3 may play a role in the aggregation and deposition of αSyn in neurons. To characterize the molecular mechanisms that underlie the interactions between FABP3 and αSyn that modulate the cellular accumulation of the latter, in this report, we used in vitro fluorescence assays combined with fluorescence microscopy, transmission electron microscopy, and quartz crystal microbalance assays to characterize in detail the process and consequences of FABP3-αSyn interaction. We demonstrated that binding of FABP3 to αSyn results in changes in the aggregation mechanism of the latter; specifically, a suppression of fibrillar forms of αSyn and also the production of aggregates with an enhanced cytotoxicity toward mice neuro2A cells. Because this interaction involved the C-terminal sequence region of αSyn, we tested a peptide derived from this region of αSyn (αSynP130-140) as a decoy to prevent the FABP3-αSyn interaction. We observed that the peptide competitively inhibited binding of αSyn to FABP3 in vitro and in cultured cells. We propose that administration of αSynP130-140 might be used to prevent the accumulation of toxic FABP3-αSyn oligomers in cells, thereby preventing the progression of Parkinson's disease.


Subject(s)
Amyloid/antagonists & inhibitors , Fatty Acid Binding Protein 3/metabolism , Neuroblastoma/pathology , Peptide Fragments/pharmacology , Protein Aggregation, Pathological/prevention & control , alpha-Synuclein/metabolism , Amyloid/metabolism , Animals , Fatty Acid Binding Protein 3/genetics , Humans , Mice , Neuroblastoma/genetics , Neuroblastoma/metabolism , Tumor Cells, Cultured , alpha-Synuclein/antagonists & inhibitors , alpha-Synuclein/genetics
10.
J Mol Neurosci ; 71(7): 1425-1435, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33907963

ABSTRACT

Data from preclinical studies propose nicotinamide adenine dinucleotide (NAD+) as a neuroprotective and bioenergetics stimulant agent to treat Alzheimer's disease (AD); however, there seems to be inconsistency between behavioral and molecular outcomes. We performed this systematic review to provide a better understanding of the effects of NAD+ in rodent AD models and to summarize the literature.Studies were identified by searching PubMed, EMBASE, Scopus, Google Scholar, and the reference lists of relevant review articles published through December 2020. The search strategy was restricted to articles about NAD+, its derivatives, and their association with cognitive function in AD rodent models. The initial search yielded 320 articles, of which 11 publications were included in our systematic review.Based on the primary outcomes, it was revealed that NAD+ improves learning and memory. The secondary endpoints also showed neuroprotective effects of NAD+ on different AD models. The proposed neuroprotective mechanisms included, but were not limited to, the attenuation of the oxidative stress, inflammation, and apoptosis, while enhancing the mitochondrial function.The current systematic review summarizes the preclinical studies on NAD+ precursors and provides evidence favoring the pro-cognitive effects of such components in rodent models of AD.


Subject(s)
Alzheimer Disease/drug therapy , NAD/therapeutic use , Neuroprotective Agents/therapeutic use , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Animals , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Apoptosis/drug effects , Behavior, Animal/drug effects , Disease Models, Animal , Drug Evaluation, Preclinical , Energy Metabolism , Mice , Mice, Transgenic , Mitochondria/physiology , NAD/pharmacology , Neuroinflammatory Diseases/drug therapy , Neuroprotective Agents/pharmacology , Niacin/pharmacology , Niacinamide/pharmacology , Niacinamide/therapeutic use , Oxidative Stress/drug effects , Protein Aggregation, Pathological/prevention & control , Rats , Synapses/drug effects , Synapses/metabolism , tau Proteins/metabolism
11.
Mol Cell Neurosci ; 112: 103612, 2021 04.
Article in English | MEDLINE | ID: mdl-33722677

ABSTRACT

The multifactorial neurological condition called Alzheimer's disease (AD) primarily affects elderly individuals. Despite the calamitous consequences of AD, curative strategies for a regimen to apply remain inadequate as several factors contribute to AD etiology. Drug repurposing is an advance strategy prior to drug discovery as various effective drugs perform through alteration of multiple targets, and the present "poly-pharmacology" can be a curative approach to complex disorders. AD's multifactorial behavior actively encourages the hypothesis for a drug design approach focused on drug repurposing. In this study, we discovered that an antifungal drug, Caspofungin (CAS) is a potent Aß aggregation inhibitor that displays significantly reduced toxicity associated with AD. Drug reprofiling and REMD simulations demonstrated that CAS interacts with the ß-sheet section, known as Aß amyloid fibrils hotspot. CAS leads to destabilization of ß-sheet and, conclusively, in its devaluation. Later, in vitro experiments were acquired in which the fibrillar volume was reduced for CAS-treated Aß peptide. For the first time ever, this study has determined an antifungal agent as the Aß amyloid aggregation's potent inhibitor. Several efficient sequence-reliant potent inhibitors can be developed in future against the amyloid aggregation for different amyloid peptide by the processing and conformational optimization of CAS.


Subject(s)
Amyloid beta-Peptides/drug effects , Antifungal Agents/pharmacology , Caspofungin/pharmacology , Protein Aggregation, Pathological/prevention & control , Alzheimer Disease/drug therapy , Amino Acid Sequence , Animals , Antifungal Agents/therapeutic use , Caspofungin/therapeutic use , Drug Repositioning , Humans , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Ligands , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Aggregation, Pathological/drug therapy , Protein Conformation , Protein Structure, Secondary/drug effects
12.
J Oleo Sci ; 70(3): 289-295, 2021 Mar 04.
Article in English | MEDLINE | ID: mdl-33583924

ABSTRACT

Glyceric acid (GA) is an oxidative product of glycerol, and its d-isomer is obtained as a phytochemical from tobacco leaves and fruits of some plants. However, the production and applications of GA have not yet been fully investigated. In this review, recent developments in the microbial production of GA and its application to bio-related materials are summarized. The sodium salt of diacylated GA showed superior surface tension-lowering activity and antitrypsin activity. GA and its glucosyl derivative had positive effects on the viability and collagen production of skin cells in vitro, respectively. Glucosyl derivatives of GA showed protective effects against heat-induced protein aggregation. In addition, the microbial production of GA using raw glycerol as the starting material was investigated. The effect of methanol, a major impurity in raw glycerol, on GA production was investigated, and mutant strains to tolerate methanol in the culture were constructed. Enantioselective production of GA using newly isolated microbial strains has also been developed.


Subject(s)
Acetobacter/metabolism , Gluconobacter/metabolism , Glyceric Acids/metabolism , Antitubercular Agents , Biofuels , Cell Survival/drug effects , Collagen/metabolism , Fermentation , Glyceric Acids/chemistry , Glyceric Acids/pharmacology , Glycerol , Isomerism , Oxidation-Reduction , Protein Aggregation, Pathological/prevention & control , Skin/cytology , Skin/metabolism , Surface-Active Agents
13.
J Phys Chem Lett ; 12(7): 1803-1813, 2021 Feb 25.
Article in English | MEDLINE | ID: mdl-33577334

ABSTRACT

Naturally occurring osmoprotectants are known to prevent aggregation of proteins under various stress factors including extreme pH and elevated temperature conditions. Here, we synthesized gold nanoparticles coated with selected osmolytes (proline, hydroxyproline, and glycine) and examined their effect on temperature-induced amyloid-formation of insulin hormone. These uniform, thermostable, and hemocompatible gold nanoparticles were capable of inhibiting both spontaneous and seed-induced amyloid aggregation of insulin. Both quenching and docking experiments suggest a direct interaction between the osmoprotectant-coated nanoparticles and aggregation-prone hydrophobic stretches of insulin. Circular-dichroism results confirmed the retention of insulin's native structure in the presence of these nanoparticles. Unlike the indirect solvent-mediated effect of free osmolytes, the inhibition effect of osmolyte-coated gold nanoparticles was observed to be mediated through their direct interaction with insulin. The results signify the protection of the exposed aggregation-prone domains of insulin from temperature-induced self-assembly through osmoprotectant-coated nanoparticles, and such effect may inspire the development of osmolyte-based antiamyloid nanoformulations.


Subject(s)
Amyloid/chemistry , Gold/chemistry , Insulin/chemistry , Metal Nanoparticles/chemistry , Protein Aggregation, Pathological/prevention & control , Amino Acid Sequence , Hydrophobic and Hydrophilic Interactions , Hydroxyproline/chemistry , Molecular Docking Simulation , Proline/chemistry , Protein Conformation , Surface Properties , Temperature , Thermodynamics
14.
J Mol Med (Berl) ; 99(3): 383-402, 2021 03.
Article in English | MEDLINE | ID: mdl-33409554

ABSTRACT

Endoplasmic reticulum (ER) stress is a common threat to photoreceptors during the pathogenesis of chronic retinopathies and often results in irreversible visual impairment. 2,3,5,6-Tetramethylpyrazine (TMP), which possesses many beneficial pharmacological activities, is a potential drug that could be used to protect photoreceptors. In the present study, we found that the cellular growth rate of 661 W cells cultured under low glucose conditions was lower than that of control cells, while the G2/M phase of the cell cycle was longer. We further found that the mitochondrial membrane potential (ΔΨm) was lower and that ER stress factor expression was increased in 661 W cells cultured under low glucose conditions. TMP reversed these trends. Visual function and cell counts in the outer nuclear layer (ONL) were low and the TUNEL-positive rate in the ONL was high in a C3H mouse model of spontaneous retinal degeneration. Similarly, visual function was decreased, and the TUNEL-positive rate in the ONL was increased in fasted C57/BL6j mice compared with control mice. On the other hand, ER stress factor expression was found to be increased in the retinas of both mouse models, as shown by reverse transcription real-time PCR (RT-qPCR) and western blotting. TMP reversed the physiological and molecular biological variations observed in both mouse models, and ATF4 expression was enhanced again. Further investigation by using western blotting illustrated that the proportion of insoluble prion protein (PRP) versus soluble PRP was reduced both in vitro and in vivo. Taken together, these results suggest that TMP increased the functions of photoreceptors by alleviating ER stress in vitro and in vivo, and the intrinsic mechanism was the ATF4-mediated inhibition of PRP aggregation. TMP may potentially be used clinically as a therapeutic agent to attenuate the functional loss of photoreceptors during the pathogenesis of chronic retinopathies. KEY MESSAGES: • Already known: TMP is a beneficial drug mainly used in clinic to enhance organ functions, and the intrinsic mechanism is still worthy of exploring. • New in the study: We discovered that TMP ameliorated retinal photoreceptors function via ER stress alleviation, which was promoted by ATF4-mediated inhibition of PRP aggregation. • Application prospect: In prospective clinical practices, TMP may potentially be used in the clinic as a therapeutic agent to attenuate the photoreceptors functional reduction in chronic retinopathies.


Subject(s)
Activating Transcription Factor 4/physiology , Endoplasmic Reticulum Stress/drug effects , Prion Proteins/drug effects , Protein Aggregates/drug effects , Protein Aggregation, Pathological/prevention & control , Pyrazines/pharmacology , Retinal Cone Photoreceptor Cells/drug effects , Retinal Degeneration/prevention & control , Animals , Cell Line, Tumor , Disease Models, Animal , Drug Evaluation, Preclinical , Electroretinography , Eye Proteins/biosynthesis , Eye Proteins/genetics , Fasting , Female , Glucose/pharmacology , Male , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Prion Proteins/chemistry , Protein Aggregation, Pathological/metabolism , Retina/metabolism , Retinal Cone Photoreceptor Cells/metabolism , Retinal Degeneration/physiopathology , Single-Blind Method , Solubility , Specific Pathogen-Free Organisms , Transcription, Genetic/drug effects
15.
Int J Med Sci ; 18(1): 199-206, 2021.
Article in English | MEDLINE | ID: mdl-33390788

ABSTRACT

Islet amyloid polypeptide (amylin), consecrated by the pancreatic ß-cells with insulin, has a significant role to play in maintaining homeostasis of islet cell hormones. Alzheimer's disease is the predominant source of dementia. However, its etiology remains uncertain; it appears that type 2 diabetes mellitus and other prediabetic states of insulin resistance contribute to the intermittent Alzheimer's disease presence. Amylin is abnormally elevated in Type II diabetes patients, accumulated into amylin aggregates, and ultimately causes apoptosis of the ß-cells, and till date, its mechanism remains unclear. Several flavonoids have inhibitory effects on amylin amyloidosis, but its inhibition mechanisms are unknown. Screening a collection of traditional compounds revealed the flavone Chrysin, a potential lead compound. Chrysin inhibits amyloid aggregate formation according to Thioflavin T binding, turbidimetry assay. We report results of molecular interaction analysis of Chrysin with amylin which shows potent binding affinity against amylin. Pharmacokinetics and Drug likeness studies of Chrysin also suggest that it is a potential lead compound. Therefore, Chrysin prevented amylin aggregation.


Subject(s)
Alzheimer Disease/prevention & control , Diabetes Mellitus, Type 2/drug therapy , Flavonoids/pharmacology , Islet Amyloid Polypeptide/metabolism , Protein Aggregation, Pathological/prevention & control , Alzheimer Disease/etiology , Alzheimer Disease/pathology , Animals , Apoptosis/drug effects , Cell Line, Tumor , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/pathology , Flavonoids/therapeutic use , Humans , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/pathology , Molecular Docking Simulation , Protein Aggregation, Pathological/etiology , Protein Aggregation, Pathological/pathology , Protein Binding , Rats
16.
Int J Biol Macromol ; 170: 33-41, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33352157

ABSTRACT

Fast green FCF (FGF) is often used in foods, pharmaceuticals, and cosmetics. However, little is known about the interactions of FGF with amyloid-ß protein (Aß) associated with Alzheimer's disease. In this study, the inhibitory effects of FGF on Aß fibrillogenesis, the disruption of preformed Aß fibrils, the reduction of Aß-induced cytotoxicity, and the attenuation of Aß-induced learning and memory impairments in mice were investigated. FGF significantly inhibited Aß fibrillogenesis and disintegrated the mature fibrils as evidenced by thioflavin T fluorescence and atomic force microscopy studies. Co-incubation of Aß with FGF greatly reduced Aß-induced cytotoxicity in vitro. Moreover, FGF showed a protective effect against cognitive impairment in Aß-treated mice. Molecular dynamics simulations further showed that FGF could synergistically interact with the Aß17-42 pentamer via electrostatic interactions, hydrogen bonds and π-π interactions, which reduced the ß-sheet content, and disordered random coils and bend structures of the Aß17-42 pentamer. This study offers a comprehensive understanding of the inhibitory effects of FGF against Aß neurotoxicity, which is critical for the search of effective food additives that can combat amyloid-associated disease.


Subject(s)
Amyloid beta-Peptides/drug effects , Amyloid/antagonists & inhibitors , Cognitive Dysfunction/prevention & control , Food Additives/therapeutic use , Lissamine Green Dyes/therapeutic use , Neuroprotective Agents/therapeutic use , Protein Aggregation, Pathological/prevention & control , Alzheimer Disease/metabolism , Alzheimer Disease/prevention & control , Amyloid/drug effects , Amyloid/toxicity , Amyloid/ultrastructure , Amyloid beta-Peptides/chemistry , Animals , Cognitive Dysfunction/etiology , Cognitive Dysfunction/metabolism , Exploratory Behavior/drug effects , Food Additives/pharmacology , Humans , Hydrogen Bonding , Lissamine Green Dyes/pharmacology , Mice , Microscopy, Atomic Force , Models, Molecular , Molecular Dynamics Simulation , Morris Water Maze Test/drug effects , Neuroprotective Agents/pharmacology , Peptide Fragments/chemistry , Peptide Fragments/drug effects , Protein Aggregation, Pathological/drug therapy , Protein Structure, Secondary/drug effects , Random Allocation , Static Electricity
17.
J Ethnopharmacol ; 268: 113640, 2021 Mar 25.
Article in English | MEDLINE | ID: mdl-33307058

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Terminalia chebula Retz. (T.chebula) is an important medicinal plant in Tibetan medicine and Ayurveda. T.chebula is known as the "King of Tibetan Medicine", due to its widespread clinical pharmacological activity such as anti-inflammatory, antioxidative, antidiabetic as well as anticancer in lots of in vivo and in vitro models. In this study, we use transgenic and/or RNAi Caenorhabditis elegans (C.elegans) model to simulation the AD pathological features induced by Aß, to detect the effect of TWE on improving Aß-induced toxicity and the corresponding molecular mechanism. AIM OF STUDY: The study aimed to tested the activities and its possible mechanism of T.chebula to against Aß1-42 induced toxicity and Aß1-42 aggregation. MATERIALS AND METHODS: Using transgenic C.elegans strain CL2006 and CL4176 as models respond to paralytic induced by Aß toxicity. The transcription factors DAF-16 and SKN-1 were analyzed used a fluorescence microscope in transgenic strains (DAF-16:GFP, SKN-1:GFP). The function of DAF-16 and SKN-1 was further investigated using loss-of-function strains by feeding RNA interference (RNAi) bacteria. To evaluate the aggregation level of Aß in the transgenic C.elegans, Thioflavin S (ThS) staining and WB visualized the levels of Aß monomers and oligomers. RESULTS: TWE treatment can significantly improve the paralysis of transgenic C.elegans caused by Aß aggregation (up to 14%). The Aß aggregates in transgenic C.elegans are significantly inhibited under TWE exposure (up to 70%). TWE increases the nuclear localization of the key transcription factor DAF-16 and HSF-1, which in turn leads to the expression of downstream Hsp-16.2 protein and exerts its inhibitory effect on Aß aggregation. Meanwhile, paralysis improved has not observed in SKN-1 mutation and/or RNAi C.elegans. CONCLUSION: Our results indicate that TWE can protect C.elegans against the Aß1-42-induced toxicity, inhibition Aß1-42 aggregation and delaying Aß-induced paralysis. The neuroprotective effect of TWE involves the activation of DAF-16/HSF-1/Hsp-16.2 pathway.


Subject(s)
Amyloid beta-Peptides/toxicity , Peptide Fragments/toxicity , Plant Extracts/therapeutic use , Protein Aggregation, Pathological/chemically induced , Protein Aggregation, Pathological/prevention & control , Terminalia , Amyloid beta-Peptides/antagonists & inhibitors , Animals , Animals, Genetically Modified , Caenorhabditis elegans , Dose-Response Relationship, Drug , Humans , Peptide Fragments/antagonists & inhibitors , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Protein Aggregation, Pathological/pathology
18.
Eur J Med Chem ; 209: 112915, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33139110

ABSTRACT

Alzheimer's disease (AD) is the most common form of dementia characterized by presence of extracellular amyloid plaques and intracellular neurofibrillary tangles composed of tau protein. Currently there are close to 50 million people living with dementia and this figure is expected to increase to 75 million by 2030 putting a huge burden on the economy due to the health care cost. Considering the effects on quality of life of patients and the increasing burden on the economy, there is an enormous need of new disease modifying therapies to tackle this disease. The current therapies are dominated by only symptomatic treatments including cholinesterase inhibitors and N-methyl-D-aspartate receptor blockers but no disease modifying treatments exist so far. After several failed attempts to develop drugs against amyloidopathy, tau targeting approaches have been in the main focus of drug development against AD. After an overview of the tauopathy in AD, this review summarizes recent findings on the development of small molecules as therapeutics targeting tau modification, aggregation, and degradation, and tau-oriented multi-target directed ligands. Overall, this work aims to provide a comprehensive and critical overview of small molecules which are being explored as a lead candidate for discovering drugs against tauopathy in AD.


Subject(s)
Alzheimer Disease/drug therapy , Neuroprotective Agents/chemistry , tau Proteins/metabolism , Animals , Benzodioxoles/pharmacology , Cholinesterase Inhibitors/pharmacology , Cholinesterases/metabolism , Curcumin/pharmacology , Humans , Molecular Targeted Therapy , Neurofibrillary Tangles/metabolism , Neuroprotective Agents/pharmacology , Phosphorylation , Plaque, Amyloid/metabolism , Protein Aggregation, Pathological/prevention & control , Protein Processing, Post-Translational , Quinazolines/pharmacology , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Thiadiazoles/pharmacology
19.
J Surg Res ; 259: 296-304, 2021 03.
Article in English | MEDLINE | ID: mdl-33131764

ABSTRACT

BACKGROUND: Chronic traumatic encephalopathy is a consequence of repetitive mild traumatic brain injury (rmTBI). These injuries can result in psychiatric disorders that are treated with amitriptyline. Amitriptyline improves neuronal regeneration in major depression via inhibition of acid sphingomyelinase. We hypothesized that acid sphingomyelinase inhibition would preserve neuronal regeneration and decrease depressive symptoms following rmTBI in a murine model. METHODS: A murine model of rmTBI was established using a weight-drop method. Mice were subjected to mTBI every other day for 7 d. Mice received amitriptyline injection 2 h prior to each mTBI. After the final mTBI, mice underwent behavioral studies or biochemical analysis. Hippocampi were analyzed for markers of neurogenesis and phosphorylated tau aggregation. RESULTS: Mice that underwent rmTBI showed increased hippocampal phosphorylated tau aggregation 1 mo following rmTBI as well as decreased neuronal regeneration by bromodeoxyuridine uptake and doublecortin immunohistochemistry. Mice with either genetic deficiency or pharmacologic inhibition of acid sphingomyelinase demonstrated improved neuronal regeneration and decreased phosphorylated tau aggregation compared to untreated rmTBI mice. Behavioral testing showed rmTBI mice spent significantly more time in the dark and waiting to initiate feeding compared to sham mice. These behaviors were partially prevented by the inhibition of acid sphingomyelinase. CONCLUSIONS: We established a murine model of rmTBI that leads to tauopathy, depression, and impaired hippocampal neurogenesis. Inhibition of acid sphingomyelinase prevented the harmful neurologic and behavioral effects of rmTBI. These findings highlight an important opportunity to improve recovery or prevent neuropsychiatric decline in patients at risk for chronic traumatic encephalopathy.


Subject(s)
Brain Concussion/drug therapy , Sphingomyelin Phosphodiesterase/antagonists & inhibitors , Amitriptyline/therapeutic use , Animals , Brain Concussion/enzymology , Brain Concussion/pathology , Brain Concussion/psychology , Disease Models, Animal , Male , Mice , Mice, Inbred C57BL , Protein Aggregation, Pathological/prevention & control , Sphingomyelin Phosphodiesterase/physiology , tau Proteins/chemistry
20.
Int J Mol Sci ; 21(23)2020 Nov 24.
Article in English | MEDLINE | ID: mdl-33255444

ABSTRACT

The formation of amyloid fibrils is linked to multiple neurodegenerative disorders, including Alzheimer's and Parkinson's disease. Despite years of research and countless studies on the topic of such aggregate formation, as well as their resulting structure, the current knowledge is still fairly limited. One of the main aspects prohibiting effective aggregation tracking is the environment's effect on amyloid-specific dyes, namely thioflavin-T (ThT). Currently, there are only a few studies hinting at ionic strength being one of the factors that modulate the dye's binding affinity and fluorescence intensity. In this work we explore this effect under a range of ionic strength conditions, using insulin, lysozyme, mouse prion protein, and α-synuclein fibrils. We show that ionic strength is an extremely important factor affecting both the binding affinity, as well as the fluorescence intensity of ThT.


Subject(s)
Amyloid/drug effects , Benzothiazoles/pharmacology , Protein Aggregates/drug effects , Protein Aggregation, Pathological/prevention & control , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Animals , Benzothiazoles/chemistry , Binding Sites/drug effects , Fluorescence , Humans , Insulin/chemistry , Kinetics , Mice , Osmolar Concentration , Parkinson Disease/metabolism , Parkinson Disease/prevention & control , Prion Proteins/chemistry , Prion Proteins/drug effects , Protein Aggregation, Pathological/metabolism , Protein Binding/drug effects , alpha-Synuclein/chemistry , alpha-Synuclein/drug effects
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