المؤلفون: Ross Chawner, Sonia Mazzitelli, Ross Jeggo, Claire E. Eyers, David Spanswick, Jasmeet Virdee, J. Mark Treherne, Alun Williams, David I.C. Scopes, Hozefa Amijee, Clive Bate, Andrew J. Doig

المصدر: Biochemistry. 51:8338-8352

مصطلحات موضوعية: Male, Programmed cell death, Circular dichroism, Cell Survival, Long-Term Potentiation, Peptide, Biochemistry, Oligomer, Mice, chemistry.chemical_compound, Alzheimer Disease, Lactate dehydrogenase, Tumor Cells, Cultured, Animals, Humans, Benzothiazoles, Protein Structure, Quaternary, Neurons, chemistry.chemical_classification, Amyloid beta-Peptides, Circular Dichroism, Long-term potentiation, Surface Plasmon Resonance, Peptide Fragments, Rats, Thiazoles, chemistry, Toxicity, Thioflavin, Protein Multimerization, Oligopeptides

الوصف: Oligomeric forms of β-amyloid (Aβ) have potent neurotoxic activity and are the primary cause of neuronal injury and cell death in Alzheimer's disease (AD). Compounds that perturb oligomer formation or structure may therefore be therapeutic for AD. We previously reported that d-[(chGly)-(Tyr)-(chGly)-(chGly)-(mLeu)]-NH(2) (SEN304) is able to inhibit Aβ aggregation and toxicity, shown primarily by thioflavin T fluorescence and MTT (Kokkoni, N. et al. (2006) N-Methylated peptide inhibitors of β-amyloid aggregation and toxicity. Optimisation of inhibitor structure. Biochemistry 45, 9906-9918). Here we extensively characterize how SEN304 affects Aβ(1-42) aggregation and toxicity, using biophysical assays (thioflavin T, circular dichroism, SDS-PAGE, size exclusion chromatography, surface plasmon resonance, traveling wave ion mobility mass spectrometry, electron microscopy, ELISA), toxicity assays in cell culture (MTT and lactate dehydrogenase in human SH-SHY5Y cells, mouse neuronal cell death and synaptophysin) and long-term potentiation in a rat hippocampal brain slice. These data, with dose response curves, show that SEN304 is a powerful inhibitor of Aβ(1-42) toxicity, particularly effective at preventing Aβ inhibition of long-term potentiation. It can bind directly to Aβ(1-42), delay β-sheet formation and promote aggregation of toxic oligomers into a nontoxic form, with a different morphology that cannot bind thioflavin T. SEN304 appears to work by inducing aggregation, and hence removal, of Aβ oligomers. It is therefore a promising lead compound for Alzheimer's disease.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::222e325f86e334145f0d7f75c2c725e9Test
https://doi.org/10.1021/bi300415vTest

المؤلفون: Clive Bate, Alun Williams

المصدر: Neuropharmacology. 61:1406-1412

مصطلحات موضوعية: Time Factors, medicine.medical_treatment, Synaptophysin, Biotin, Enzyme-Linked Immunosorbent Assay, Hippocampal formation, Transfection, Synapse, Amyloid beta-Protein Precursor, Mice, Cellular and Molecular Neuroscience, Cricetulus, Cricetinae, medicine, Animals, Dementia, Cells, Cultured, Cerebral Cortex, Neurons, Pharmacology, Phospholipase A, Amyloid beta-Peptides, Dose-Response Relationship, Drug, Ethanol, biology, Dementia with Lewy bodies, Central Nervous System Depressants, Embryo, Mammalian, medicine.disease, Peptide Fragments, Cell biology, Phospholipases A2, Biochemistry, Synapses, alpha-Synuclein, biology.protein, Calcium, Peptides, Synaptosomes, Prostaglandin E

الوصف: The loss of synapses and a corresponding reduction in synaptic proteins are histopathological features of Alzheimer's disease that correlate strongly with dementia. Here we report that stable Aβ oligomers secreted by 7PA2 cells reduced the amount of synaptophysin, a protein used as an indicator of synapse density, in cultured cortical and hippocampal neurons. Pre-treatment with physiologically relevant concentrations of ethanol (0.02-0.08%) protected neurons against Aβ-induced synapse damage. Ethanol also protected neurons against synapse damage induced by α-synuclein (αSN), pre-synaptic aggregates of which are characteristic of Parkinson's disease and dementia with Lewy bodies. Exposure of neurons to ethanol did not affect the accumulation of Aβ at synapses, rather it reduced the Aβ and αSN-induced activation of cytoplasmic phospholipase A(2) (cPLA(2)) within synapses. Ethanol did not affect synapse damage caused by platelet-activating factor or prostaglandin E(2), bioactive lipids that are formed following the activation of cPLA(2). These results may help explain epidemiological reports that moderate alcohol consumption protects against the development of dementia in Alzheimer's and Parkinson's diseases.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e165fa226f7bb9fbe0aa05544dde0261Test
https://doi.org/10.1016/j.neuropharm.2011.08.030Test

المؤلفون: Victoria Ingham, Alun Williams, Clive Bate

المصدر: Neuropharmacology. 60:365-372

مصطلحات موضوعية: Gene isoform, Phospholipase A2 Inhibitors, Prions, Organophosphonates, Peptide, Arachidonic Acids, Biology, Mice, Cellular and Molecular Neuroscience, chemistry.chemical_compound, Phospholipase A2, Animals, Humans, Receptor, Lipid raft, Cells, Cultured, Cerebral Cortex, Neurons, Pharmacology, chemistry.chemical_classification, Phospholipase A, Platelet-activating factor, Cholesterol, Peptide Fragments, Cell biology, Phospholipases A2, Protein Transport, chemistry, Biochemistry, biology.protein, lipids (amino acids, peptides, and proteins)

الوصف: The prion diseases are characterised by the formation of the disease-associated isoform of the prion protein (PrP(Sc)) and the production of disease-related peptides. The prion derived peptide PrP82-146 bound readily to cortical neurons and was found within detergent resistant membranes that are commonly called lipid rafts. It was not found within lysosomes and the slow degradation of PrP82-146 resulted in a half-life of approximately 5 days. In cortical neurons pre-treated with phospholipase A(2) (PLA(2)) inhibitors (AACOCF(3) or MAFP) less PrP82-146 entered lipid rafts, more PrP82-146 was found within lysosomes and the half-life of PrP82-146 was reduced to 24 h. Similarly, pre-treatment of neurons with platelet-activating factor (PAF) receptor antagonists (Hexa-PAF and ginkgolide B) increased the entry of PrP82-146 into lysosomes and reduced its half-life. Furthermore, the addition of PAF reversed the effects of PLA(2) inhibitors on PrP82-146 trafficking. PAF controlled the amount of cholesterol in cell membranes and the effects of PAF receptor antagonists on the trafficking of PrP82-146 were reversed by the addition of cholesterol. We conclude that activation of PLA(2) and the production of PAF control a cholesterol-sensitive pathway that affects the cellular localisation and hence the fate of PrP82-146 in neurons.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::727fa08e89f717e9c89224629290d756Test
https://doi.org/10.1016/j.neuropharm.2010.10.001Test

المؤلفون: Mourad Tayebi, Alun Williams, Luisa Diomede, Clive Bate, Mario Salmona

المصدر: Neurotoxicity Research. 17:203-214

مصطلحات موضوعية: Simvastatin, Docosahexaenoic Acids, Prions, animal diseases, Synaptophysin, Enzyme-Linked Immunosorbent Assay, In Vitro Techniques, Hippocampal formation, Neurotransmission, Toxicology, Hippocampus, Synapse, Mice, Animals, Humans, Neurotoxin, Drug Interactions, Cells, Cultured, Cerebral Cortex, Mice, Knockout, Neurons, chemistry.chemical_classification, Dose-Response Relationship, Drug, biology, Caspase 3, General Neuroscience, Embryo, Mammalian, Eicosapentaenoic acid, Peptide Fragments, nervous system diseases, Cell biology, Neuroprotective Agents, Eicosapentaenoic Acid, Gene Expression Regulation, nervous system, chemistry, Biochemistry, Docosahexaenoic acid, Fatty Acids, Unsaturated, biology.protein, lipids (amino acids, peptides, and proteins), Hydroxymethylglutaryl-CoA Reductase Inhibitors, Synaptosomes, Polyunsaturated fatty acid

الوصف: A loss of synapses is characteristic of the early stages of the prion diseases. Here we modelled the synapse damage that occurs in prion diseases by measuring the amount of synaptophysin, a pre-synaptic membrane protein essential for neurotransmission, in cortical or hippocampal neurones incubated with the disease associated isoform of the prion protein (PrP(Sc)), or with the prion-derived peptide PrP82-146. The addition of PrP(Sc) or PrP82-146 caused a dose-dependent reduction in the synaptophysin content of PrP wildtype neurones indicative of synapse damage. They did not affect the synaptophysin content of PrP null neurones. The loss of synaptophysin in PrP wildtype neurones was preceded by the accumulation of PrP82-146 within synapses. Since supplements containing polyunsaturated fatty acids (PUFA) are frequently taken for their perceived health benefits including reported amelioration of neurodegenerative conditions, the effects of some common PUFA on prion-mediated synapse damage were examined. Pre-treatment of cortical or hippocampal neurones with docosahexaenoic (DHA) or eicosapentaenoic acids (EPA) protected neurones against the loss of synaptophysin induced by PrP82-146 or PrP(Sc). This effect of DHA and EPA was selective as they did not alter the loss of synaptophysin induced by a snakevenom neurotoxin. The effects of DHA and EPA were associated with a significant reduction in the amount of FITC-PrP82-146 that accumulated within synapses. Such observations raise the possibility that supplements containing PUFA may protect against the synapse damage and cognitive loss seen during the early stages of prion diseases.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5351409a315ff0f09ced6daba2de3c03Test
https://doi.org/10.1007/s12640-009-9093-2Test

المؤلفون: Alun Williams, Harriet McHale-Owen, Clive Bate, William Nolan, Craig Osborne, Ewan West

المصدر: Neuropharmacology. 101

مصطلحات موضوعية: 0301 basic medicine, medicine.medical_specialty, Cell signaling, Prions, Synaptophysin, Enzyme-Linked Immunosorbent Assay, Cell Membrane Structures, Synapse, 03 medical and health sciences, Cellular and Molecular Neuroscience, 0302 clinical medicine, Phospholipase A2, Alzheimer Disease, Internal medicine, medicine, Humans, Cognitive decline, Receptor, Cells, Cultured, Aged, Pharmacology, Neurons, Amyloid beta-Peptides, biology, medicine.disease, Peptide Fragments, Temporal Lobe, Cell biology, Glimepiride, Phospholipases A2, 030104 developmental biology, Endocrinology, Cholesterol, Sulfonylurea Compounds, biology.protein, Female, Alzheimer's disease, 030217 neurology & neurosurgery, Immunosuppressive Agents, medicine.drug, Synaptosomes

الوصف: Alzheimer's disease is associated with the accumulation within the brain of amyloid-β (Aβ) peptides that damage synapses and affect memory acquisition. This process can be modelled by observing the effects of Aβ on synapses in cultured neurons. The addition of picomolar concentrations of soluble Aβ derived from brain extracts triggered the loss of synaptic proteins including synaptophysin, synapsin-1 and cysteine string protein from cultured neurons. Glimepiride, a sulphonylurea used for the treatment of diabetes, protected neurons against synapse damage induced by Aβ. The protective effects of glimepiride were multi-faceted. Glimepiride treatment was associated with altered synaptic membranes including the loss of specific glycosylphosphatidylinositol (GPI)-anchored proteins including the cellular prion protein (PrP(C)) that acts as a receptor for Aβ42, increased synaptic gangliosides and altered cell signalling. More specifically, glimepiride reduced the Aβ-induced increase in cholesterol and the Aβ-induced activation of cytoplasmic phospholipase A2 (cPLA2) in synapses that occurred within cholesterol-dense membrane rafts. Aβ42 binding to glimepiride-treated neurons was not targeted to membrane rafts and less Aβ42 accumulated within synapses. These studies indicate that glimepiride modified the membrane micro-environments in which Aβ-induced signalling leads to synapse damage. In addition, soluble PrP(C), released from neurons by glimepiride, neutralised Aβ-induced synapse damage. Such observations raise the possibility that glimepiride may reduce synapse damage and hence delay the progression of cognitive decline in Alzheimer's disease.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::59d25fa67e0af330b43255e00784097eTest
https://pubmed.ncbi.nlm.nih.gov/26432105Test

المؤلفون: Ronald S. Boshuizen, Clive Bate, Alun Williams

المصدر: Journal of Neuroimmunology. 170:62-70

مصطلحات موضوعية: Cell Survival, Prions, medicine.drug_class, Recombinant Fusion Proteins, CD14, Immunology, Lipopolysaccharide Receptors, Peptide, Monoclonal antibody, Antibodies, Monocytes, Epitope, Epitopes, Mice, Chimera (genetics), medicine, Animals, Humans, Immunology and Allergy, Cells, Cultured, Cerebral Cortex, Mice, Knockout, Neurons, chemistry.chemical_classification, Cell Death, biology, Antibodies, Monoclonal, Molecular biology, Coculture Techniques, Peptide Fragments, In vitro, Mice, Inbred C57BL, nervous system, Neurology, chemistry, Immunoglobulin G, Knockout mouse, biology.protein, Microglia, Neurology (clinical), Antibody, Epitope Mapping

الوصف: Microglial cells killed primary cortical neurons exposed to the prion (PrP)-derived peptide HuPrP106-126. The survival of HuPrP106-126-damaged neurons was increased by pre-treating microglial cells with anti-CD14 antibodies, while microglial cells from CD14 knockout mice failed to kill HuPrP106-126-damaged neurons. In addition, HuPrP106-126-damaged neurons selectively bound a CD14-IgG chimera. The killing of HuPrP106-126-damaged neurons by human monocytes was epitope specific; it was reduced by pre-treating monocytes with some anti-CD14 monoclonal antibodies (mabs) (60bca, 3C10 or MAB3832), but not others (26ic or MAB3831). None of the mabs affected the survival of HuPrP106-126-damaged neurons in the absence of monocytes.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9620daf56f0981058c098de0d6c31155Test
https://doi.org/10.1016/j.jneuroim.2005.08.021Test

المؤلفون: Clive Bate, Robert Veerhuis, Alun Williams, Piet Eikelenboom

المساهمون: Neurology

المصدر: Neuroreport, 15(9), 1427-1430. Lippincott Williams and Wilkins

مصطلحات موضوعية: Cell Survival, Ratón, Recombinant Fusion Proteins, CD14, medicine.medical_treatment, Lipopolysaccharide Receptors, Cell Communication, Mice, medicine, Animals, Interleukin 6, Cells, Cultured, Neurons, Amyloid beta-Peptides, Cell Death, biology, Microglia, General Neuroscience, medicine.disease, Peptide Fragments, Cell biology, medicine.anatomical_structure, Cytokine, nervous system, Immunoglobulin G, biology.protein, Neuroglia, Neuron, Alzheimer's disease, Neuroscience

الوصف: Activated microglia are closely associated with neuronal damage in Alzheimer's disease. In the present study, neurons exposed to low concentrations of amyloid-beta1-42, a toxic fragment of the amyloid-beta protein, were killed by microglia in a process that required cell-cell contact. Pre-treating microglia with polyclonal antibodies to the CD14 protein, or treating neurons exposed to amyloid-beta1-42 with a CD14-IgG chimera, prevented the killing of amyloid-beta1-42 damaged neurons by microglia. Moreover, microglia from CD14 null mice failed to kill amyloid-beta1-42 damaged neurons. Increased neuronal survival was accompanied by a significant reduction in the production of interleukin-6 indicative of reduced microglial activation. These results indicate an important role for CD14 in the recognition and subsequent killing of amyloid-beta damaged neurons by microglia.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f595d61fb54c7128b59ab9bd82f8caebTest
https://doi.org/10.1097/01.wnr.0000132203.76836.16Test

المؤلفون: Clive Bate, Scott Rutherford, Alun Williams, Mike B. Gravenor, Stuart Reid

المصدر: NeuroReport. 13:1933-1938

مصطلحات موضوعية: PrPSc Proteins, Cell Survival, Prions, animal diseases, Glutamic Acid, Prostaglandin, Biology, Dinoprostone, Prion Diseases, Mice, Neuroblastoma, chemistry.chemical_compound, Fetus, Tumor Cells, Cultured, medicine, Animals, Neurotoxin, Cyclooxygenase Inhibitors, Enzyme Inhibitors, Cerebral Cortex, Neurons, chemistry.chemical_classification, Cyclooxygenase 2 Inhibitors, Dose-Response Relationship, Drug, Microglia, General Neuroscience, Anti-Inflammatory Agents, Non-Steroidal, Neurotoxicity, Membrane Proteins, medicine.disease, Peptide Fragments, In vitro, nervous system diseases, Isoenzymes, Mice, Inbred C57BL, Neuroprotective Agents, medicine.anatomical_structure, Enzyme, Animals, Newborn, chemistry, Eicosanoid, Biochemistry, Cyclooxygenase 2, Prostaglandin-Endoperoxide Synthases, Cyclooxygenase 1, Arachidonic acid

الوصف: The mechanisms of neuronal loss during the course of the prion diseases are not fully understood. In this study, neurones treated with certain non-steroidal anti-inflammatory drugs (NSAIDs) were protected against the otherwise toxic effects of a peptide derived from the prion protein, or extracts containing infectious prions (PrP SC ). These NSAIDs inhibit the cyclo-oxygenase (cox) enzymes that metabolise arachidonic acid to prostaglandins (PG). Conversely, drugs that inhibited the metabolism of arachidonic acid to leucotrienes enhanced neurotoxicity. Studies with selective inhibitors highlighted the importance of the cox- 1 isoform in prion-induced neurotoxicity. The cox-I inhibitors also inhibited neuronal PGE 2 production and protected both neuroblastoma cells and primary cortical neurones against prions. They also reduced microglia-mediated killing of prion-treated neurones.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ae6aaf2fc0ce08de17c784ae58693083Test
https://doi.org/10.1097/00001756-200210280-00021Test

المؤلفون: Jan P. M. Langeveld, Ronald S. Boshuizen, Alun Williams, Clive Bate

المصدر: NeuroReport, 13(13), 1695-1700
NeuroReport 13 (2002) 13

مصطلحات موضوعية: Central Nervous System, Programmed cell death, Time Factors, Cell Survival, Prions, animal diseases, Cell Communication, Biology, cultured-cells, Prion Diseases, Mice, Neuroblastoma, Degenerative disease, neurotoxicity, Reaction Time, Tumor Cells, Cultured, medicine, Animals, CIDC - Divisie Bacteriologie en TSE's, Neurons, disease, Microglia, Interleukin-6, Tumor Necrosis Factor-alpha, Cell growth, Chemotaxis, General Neuroscience, Neurotoxicity, medicine.disease, Coculture Techniques, Peptide Fragments, In vitro, nervous system diseases, medicine.anatomical_structure, nervous system, scrapie prion proteins, Culture Media, Conditioned, Nerve Degeneration, Neuroglia, Neuron, Neuroscience, Interleukin-1

الوصف: Previous studies have demonstrated a role for microglia in the neuronal loss that occurs in the transmissible spongiform encephalopathies or prion diseases. In the present studies, the processes that lead to the death of neurones treated with synthetic peptides derived from the prion protein (PrP) were fully activated within 1 h, although neuronal cell death was not seen until 24 h later. Similarly, neurones exposed to PrP peptides for only 1 h activated microglia and a temporal relationship between the production of interleukin-6, an indicator of microglial activation, and microglial killing of PrP-treated neurones was also demonstrated. Activation of microglia and microglia-mediated killing of PrP-treated neurones or scrapie-infected neuroblastoma cells were maximal only when microglia were in direct contact with neurones.

وصف الملف: application/octet-stream; text/html

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::25fd3ea8c66858a797ca4be75a84a2c5Test
https://doi.org/10.1097/00001756-200209160-00025Test

المؤلفون: Victoria Ingham, Alun Williams, Clive Bate

المصدر: Journal of Neuroinflammation

مصطلحات موضوعية: Lipopolysaccharides, Receptor complex, medicine.medical_specialty, Time Factors, Prions, CD14, medicine.medical_treatment, Immunology, Lipopolysaccharide Receptors, Biology, Pharmacology, Cellular and Molecular Neuroscience, Membrane Microdomains, Internal medicine, medicine, Animals, Humans, Hypoglycemic Agents, Cells, Cultured, Mice, Knockout, Amyloid beta-Peptides, Microglia, Dose-Response Relationship, Drug, General Neuroscience, Macrophages, Research, Peptide Fragments, Mice, Inbred C57BL, Glimepiride, Cytokine, medicine.anatomical_structure, Endocrinology, Sulfonylurea Compounds, Neurology, Gene Expression Regulation, Cytokines, Cytokine secretion, Tumor necrosis factor alpha, Cell activation, Neuroglia, Glipizide, Immunosuppressive Agents, medicine.drug

الوصف: Background Activated microglia are associated with deposits of aggregated proteins within the brains of patients with Alzheimer’s disease (AD), Parkinson’s disease (PD) and prion diseases. Since the cytokines secreted from activated microglia are thought to contribute to the pathogenesis of these neurodegenerative diseases, compounds that suppress cytokine production have been identified as potential therapeutic targets. CD14 is a glycosylphosphatidylinositol (GPI)- anchored protein that is part of a receptor complex that mediates microglial responses to peptides that accumulate in prion disease (PrP82-146), AD (amyloid-β (Aβ)42) and PD (α-synuclein (αSN)). As some GPI-anchored proteins are released from cells by treatment with glimepiride, a sulphonylurea used for the treatment of diabetes, the effects of glimepiride upon CD14 expression and cytokine production from cultured macrophages were studied. Methods RAW 264 cells and microglial cells were treated with glimepiride or phosphatidylinositol (PI)-phospholipase C (PLC) and the expression of cell receptors was analysed by ELISA and immunoblot. Treated cells were subsequently incubated with Aβ42, αSN, PrP82-146 or lipopolysaccharide (LPS) and the amounts of Toll-like receptor (TLR)-4, tumour necrosis factor (TNF), interleukin (IL)-1 and IL-6 measured. Results Glimepiride released CD14 from RAW 264 cells and microglial cells. Pre-treatment with glimepiride significantly reduced TNF, IL-1 and IL-6 secretion from RAW 264 and microglial cells incubated with LPS, Aβ42, αSN and PrP82-146. Glimepiride also reduced the LPS, Aβ42, αSN and PrP82-146-induced translocation of TLR-4 into membrane rafts that is associated with cell activation. These effects of glimepiride were also seen after digestion of RAW 264 cells with PI-phospholipase C (PLC). In addition, the effects of glimepiride were blocked by pharmacological inhibition of GPI-PLC. The cytokine production was CD14-dependent; it was reduced in microglia from CD14 knockout mice and was blocked by antiserum to CD14. Conclusions RAW 264 and microglial cell responses to Aβ1–42, αSN, PrP82-146 and LPS are dependent upon CD14 expression. Glimepiride induced the shedding of CD14 from cells by activation of GPI-PLC and consequently reduced cytokine production in response to Aβ42, αSN, PrP82-146 and LPS. These results suggest that glimepiride acts as a novel anti-inflammatory agent that could modify the progression of neurodegenerative diseases.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::05affdca7acbf94273220140472f2c83Test
https://pubmed.ncbi.nlm.nih.gov/24952384Test